Nutritional status influences socially regulated foraging ontogeny in honey bees.

PubMed

Toth, Amy L; Kantarovich, Sara; Meisel, Adam F; Robinson, Gene E

2005-12-01

In many social insects, including honey bees, worker energy reserve levels are correlated with task performance in the colony. Honey bee nest workers have abundant stored lipid and protein while foragers are depleted of these reserves; this depletion precedes the shift from nest work to foraging. The first objective of this study was to test the hypothesis that lipid depletion has a causal effect on the age at onset of foraging in honey bees (Apis mellifera L.). We found that bees treated with a fatty acid synthesis inhibitor (TOFA) were more likely to forage precociously. The second objective of this study was to determine whether there is a relationship between social interactions, nutritional state and behavioral maturation. Since older bees are known to inhibit the development of young bees into foragers, we asked whether this effect is mediated nutritionally via the passage of food from old to young bees. We found that bees reared in social isolation have low lipid stores, but social inhibition occurs in colonies in the field, whether young bees are starved or fed. These results indicate that although social interactions affect the nutritional status of young bees, social and nutritional factors act independently to influence age at onset of foraging. Our findings suggest that mechanisms linking internal nutritional physiology to foraging in solitary insects have been co-opted to regulate altruistic foraging in a social context.

Leaders are more attractive: birds with bigger yellow breast patches are followed by more group-mates in foraging groups.

PubMed

Tóth, Zoltán; Griggio, Matteo

2011-01-01

Social network theory provides a perfect tool to better understand the population-level consequences of how individuals interact and make their decisions; however, this approach is generally overlooked among evolutionary biologists interested in social relationships. Here, we used social network analysis to examine the patterns of leader-follower interactions in relation to individual characteristics in foraging groups of free-living rock sparrows (Petronia petronia). We found that yellow feather ornamentation, a carotenoid-based trait, was the best predictor of leadership: birds with bigger ornaments exerted greater influence in the foraging groups and were followed by more group-mates than less elaborate individuals. An individual's tendency for eliciting followings was not influenced by sex, condition or the level of parental investment. None of the above individual characteristics had significant effect on the tendency of individuals to follow others. Our results indicate that a sexually selected trait can also play a significant role in group coordination and social organization of a species.

Patch depletion, niche structuring and the evolution of co-operative foraging

PubMed Central

2011-01-01

Background Many animals live in groups. One proposed reason is that grouping allows cooperative food finding. Group foraging models suggest that grouping could increase food finding rates, but that such group processes could be evolutionarily unstable. These models assume discrete food patches which are fully detectable. However, often animals may only be able to perceive local parts of larger-scale environmental patterns. We therefore use a spatial individual-based model where food patches are aggregates of food items beyond the scale of individual perception. We then study the evolution of foraging and grouping behavior in environments with different resource distributions. Results Our results show that grouping can evolve to increase food intake rates. Two kinds of grouping evolve: traveling pairs and opportunistic grouping, where individuals only aggregate when feeding. Grouping evolves because it allows individuals to better sense and deplete patches. Such enhanced patch depletion is particularly apparent on fragmented and partially depleted patches, which are especially difficult for solitary foragers to deplete. Solitary foragers often leave a patch prematurely because a whole patch cannot be observed directly. In groups, individuals that are still eating allow other individuals that inadvertently leave the patch, to return and continue feeding. For this information sharing a grouping tendency is sufficient and observing whether a neighbor is eating is not necessary. Grouping therefore leads to a release from individual sensing constraints and a shift in niche specialization, allowing individuals to better exploit partially depleted patches. Conclusions The evolved group foraging can be seen as cooperative in the sense that it leads to a mutually-beneficial synergy: together individuals can achieve more than on their own. This cooperation exists as a group-level process generated by the interaction between grouping and the environment. Thus we reveal how such a synergy can originate in evolution as a side-effect of grouping via multi-level selection. Here there is no cooperative dilemma as individuals cannot avoid producing information for their neighbors. This scenario may be a useful starting point for studying the evolution of further social and cooperative complexity. PMID:22093680

Size-mediated response to public cues of predation risk in a tropical stream fish.

PubMed

Elvidge, C K; Ramnarine, I W; Godin, J-G J; Brown, G E

2010-11-01

In order to investigate any size-dependent differences between behavioural patterns, wild-caught Hart's rivulus Rivulus hartii of varying sizes were exposed to chemical alarm cues extracted from the skin of conspecifics or heterospecific Poecilia reticulata, or a tank water control, in a series of laboratory trials. In response to conspecific alarm cues, R. hartii subjects of the range of body sizes tested exhibited consistent, size-independent antipredator behaviours that were characterized by decreased locomotory activity and foraging levels and increased refuging behaviour. Conversely, focal R. hartii demonstrated significant size-dependent trends in response to heterospecific alarm cues, with smaller individuals exhibiting antipredator responses and larger individuals shifting their behaviour to increased levels of activity consistent with a foraging, or predatory, response. These results show that the behavioural responses of individual R. hartii to publicly available chemical alarm cues from heterospecifics are mediated by the size of the receiver. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

Foraging decisions and behavioural flexibility in trap-building predators: a review.

PubMed

Scharf, Inon; Lubin, Yael; Ovadia, Ofer

2011-08-01

Foraging theory was first developed to predict the behaviour of widely-foraging animals that actively search for prey. Although the behaviour of sit-and-wait predators often follows predictions derived from foraging theory, the similarity between these two distinct groups of predators is not always obvious. In this review, we compare foraging activities of trap-building predators (mainly pit-building antlions and web-building spiders), a specific group of sit-and-wait predators that construct traps as a foraging device, with those of widely-foraging predators. We refer to modifications of the trap characteristics as analogous to changes in foraging intensity. Our review illustrates that the responses of trap-building and widely-foraging predators to different internal and external factors, such as hunger level, conspecific density and predation threat are quite similar, calling for additional studies of foraging theory using trap-building predators. In each chapter of this review, we summarize the response of trap-building predators to a different factor, while contrasting it with the equivalent response characterizing widely-foraging predators. We provide here evidence that the behaviour of trap-building predators is not stereotypic or fixed as was once commonly accepted, rather it can vary greatly, depending on the individual's internal state and its interactions with external environmental factors. © 2010 The Authors. Biological Reviews © 2010 Cambridge Philosophical Society.

Effect of corn dry distiller grains plus solubles supplementation level on performance and digestion characteristics of steers grazing native range during forage growing season.

PubMed

Martínez-Pérez, M F; Calderón-Mendoza, D; Islas, A; Encinias, A M; Loya-Olguín, F; Soto-Navarro, S A

2013-03-01

Two experiments were conducted to evaluate effects of corn dry distiller grains plus condensed solubles (DDGS) supplementation level on performance digestion characteristics of steers grazing native range during the forage growing season. In the performance study, 72 (206 ± 23.6 kg; 2008) and 60 (230 ± 11.3 kg; 2009) English crossbred steer calves were used in a randomized complete block design replicated over 2 yr. The grazing periods lasted 56 and 58 d and started on August 11 and 18 for 2008 and 2009, respectively. Each year, steers were blocked by BW (light, medium, and heavy), stratified by BW within blocks, and randomly assigned to 1 of 4 grazing groups. Each grazing group (6 steers in 2008 and 5 in 2009) was assigned to a DDGS supplementation levels (0, 0.2, 0.4, and 0.6% BW). Grazing group served as the experimental unit with 12 groups per year receiving 1 of 4 treatments for 2 yr (n = 6). In the metabolism study, 16 English crossbred steers (360 ± 28.9 kg) fitted with ruminal cannulas grazing native range during the summer growing season were used in a completely randomized design to evaluate treatment effects on forage intake and digestion. The experiment was conducted during the first and second weeks of October 2008. Steers were randomly assigned to supplement level (0, 0.2, 0.4, and 0.6% BW; n = 4) and grazed a single native range pasture with supplements offered individually once daily at 0700 h. In the performance study, ADG (0.64, 0.75, 0.80, and 0.86 ± 0.03 kg/d for 0, 0.2, 0.4, and 0.6% BW, respectively) increased linearly (P = 0.01) with increasing DDGS supplementation level. In the metabolism study, forage OM, NDF, CP, and ether extract (EE) intake decreased (P ≤ 0.05) linearly with increasing DDGS supplementation level. Total CP and EE intake increased (P ≤ 0.002) with increasing DDGS supplementation level. Digestibility of OM, NDF, and EE increased (linear; P ≤ 0.008) whereas the soluble CP fraction of forage masticate sample linearly increased (P = 0.01) and slowly degradable CP fraction linearly decreased (P = 0.05) with increasing DDGS supplementation level. Forage in situ masticate DM and NDF disappearance rate decreased (quadratic; P ≤ 0.05) and DDGS in situ DM disappearance rate increased (linear; P = 0.03) with increasing supplementation levels. These results indicate that DDGS supplementation enhanced grazing performance and total-tract digestion of steers grazing native range during the forage growing season.

Downregulation of vitellogenin gene activity increases the gustatory responsiveness of honey bee workers (Apis mellifera)

PubMed Central

Amdam, Gro V.; Norberg, Kari; Page, Robert E.; Erber, Joachim; Scheiner, Ricarda

2008-01-01

In the honey bee (Apis mellifera), young workers usually perform tasks in the nest while older workers forage in the field. The behavioral shift from nest-task to foraging activity is accompanied by physiological and sensory changes so that foragers can be characterized by a higher juvenile hormone (JH) level, a lower vitellogenin protein titer, and an increased responsiveness to water and sucrose stimuli. JH was hypothesized to be the key mediator of behavioral development, physiology, and sensory sensitivity in honey bee workers. Recent research, however, has shown that JH is controlled by the hemolymph vitellogenin level, which implies that the fat body specific vitellogenin gene can be a key regulator of behavioral change. Here, we show that downregulation of vitellogenin activity by RNA interference (RNAi) causes an increase in the gustatory responsiveness of worker bees. Our observations suggest that vitellogenin is an important regulator of long-term changes in honey bee behavior. PMID:16466813

Trait-mediated trophic interactions: is foraging theory keeping up?

Treesearch

Steven F. Railsback; Bret C. Harvey

2013-01-01

Many ecologists believe that there is a lack of foraging theory that works in community contexts, for populations of unique individuals each making trade-offs between food and risk that are subject to feedbacks from behavior of others. Such theory is necessary to reproduce the trait-mediated trophic interactions now recognized as widespread and strong. Game theory can...

Flight restriction prevents associative learning deficits but not changes in brain protein-adduct formation during honeybee ageing.

PubMed

Tolfsen, Christina C; Baker, Nicholas; Kreibich, Claus; Amdam, Gro V

2011-04-15

Honeybees (Apis mellifera) senesce within 2 weeks after they discontinue nest tasks in favour of foraging. Foraging involves metabolically demanding flight, which in houseflies (Musca domestica) and fruit flies (Drosophila melanogaster) is associated with markers of ageing such as increased mortality and accumulation of oxidative damage. The role of flight in honeybee ageing is incompletely understood. We assessed relationships between honeybee flight activity and ageing by simulating rain that confined foragers to their colonies most of the day. After 15 days on average, flight-restricted foragers were compared with bees with normal (free) flight: one group that foraged for ∼15 days and two additional control groups, for flight duration and chronological age, that foraged for ∼5 days. Free flight over 15 days on average resulted in impaired associative learning ability. In contrast, flight-restricted foragers did as well in learning as bees that foraged for 5 days on average. This negative effect of flight activity was not influenced by chronological age or gustatory responsiveness, a measure of the bees' motivation to learn. Contrasting their intact learning ability, flight-restricted bees accrued the most oxidative brain damage as indicated by malondialdehyde protein adduct levels in crude cytosolic fractions. Concentrations of mono- and poly-ubiquitinated brain proteins were equal between the groups, whereas differences in total protein amounts suggested changes in brain protein metabolism connected to forager age, but not flight. We propose that intense flight is causal to brain deficits in aged bees, and that oxidative protein damage is unlikely to be the underlying mechanism.

Flight restriction prevents associative learning deficits but not changes in brain protein-adduct formation during honeybee ageing

PubMed Central

Tolfsen, Christina C.; Baker, Nicholas; Kreibich, Claus; Amdam, Gro V.

2011-01-01

SUMMARY Honeybees (Apis mellifera) senesce within 2 weeks after they discontinue nest tasks in favour of foraging. Foraging involves metabolically demanding flight, which in houseflies (Musca domestica) and fruit flies (Drosophila melanogaster) is associated with markers of ageing such as increased mortality and accumulation of oxidative damage. The role of flight in honeybee ageing is incompletely understood. We assessed relationships between honeybee flight activity and ageing by simulating rain that confined foragers to their colonies most of the day. After 15 days on average, flight-restricted foragers were compared with bees with normal (free) flight: one group that foraged for ∼15 days and two additional control groups, for flight duration and chronological age, that foraged for ∼5 days. Free flight over 15 days on average resulted in impaired associative learning ability. In contrast, flight-restricted foragers did as well in learning as bees that foraged for 5 days on average. This negative effect of flight activity was not influenced by chronological age or gustatory responsiveness, a measure of the bees' motivation to learn. Contrasting their intact learning ability, flight-restricted bees accrued the most oxidative brain damage as indicated by malondialdehyde protein adduct levels in crude cytosolic fractions. Concentrations of mono- and poly-ubiquitinated brain proteins were equal between the groups, whereas differences in total protein amounts suggested changes in brain protein metabolism connected to forager age, but not flight. We propose that intense flight is causal to brain deficits in aged bees, and that oxidative protein damage is unlikely to be the underlying mechanism. PMID:21430210

Personality, foraging behavior and specialization: integrating behavioral and food web ecology at the individual level.

PubMed

Toscano, Benjamin J; Gownaris, Natasha J; Heerhartz, Sarah M; Monaco, Cristián J

2016-09-01

Behavioral traits and diet were traditionally thought to be highly plastic within individuals. This view was espoused in the widespread use of optimality models, which broadly predict that individuals can modify behavioral traits and diet across ecological contexts to maximize fitness. Yet, research conducted over the past 15 years supports an alternative view; fundamental behavioral traits (e.g., activity level, exploration, sociability, boldness and aggressiveness) and diet often vary among individuals and this variation persists over time and across contexts. This phenomenon has been termed animal personality with regard to behavioral traits and individual specialization with regard to diet. While these aspects of individual-level phenotypic variation have been thus far studied in isolation, emerging evidence suggests that personality and individual specialization may covary, or even be causally related. Building on this work, we present the overarching hypothesis that animal personality can drive specialization through individual differences in various aspects of consumer foraging behavior. Specifically, we suggest pathways by which consumer personality traits influence foraging activity, risk-dependent foraging, roles in social foraging groups, spatial aspects of foraging and physiological drivers of foraging, which in turn can lead to consistent individual differences in food resource use. These pathways provide a basis for generating testable hypotheses directly linking animal personality to ecological dynamics, a major goal in contemporary behavioral ecology.

40 CFR 180.361 - Pendimethalin; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., pome, group 11 0.10 Fruit, stone, group 12 0.10 Garlic 0.1 Grape 0.1 Grass forage, fodder, and hay crop group 17, forage 20 Grass forage, fodder, and hay crop group 17, hay 13 Grass forage, fodder, and hay... specified in the table. Commodity Parts per million Expiration/revocation date Bermuda grass, forage 25 12...

40 CFR 180.361 - Pendimethalin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., pome, group 11 0.10 Fruit, stone, group 12 0.10 Garlic 0.1 Grape 0.1 Grass forage, fodder, and hay crop group 17, forage 20 Grass forage, fodder, and hay crop group 17, hay 13 Grass forage, fodder, and hay... specified in the table. Commodity Parts per million Expiration/revocation date Bermuda grass, forage 25 12...

75 FR 4279 - Pendimethalin; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

...-dimethyl-2,6- dinitrobenzenamine, in or on grass forage, fodder, and hay crop group 17, forage; grass forage, fodder, and hay crop group 17, hay; and grass forage, fodder, and hay crop group 17, straw. BASF...-dinitrobenzyl alcohol, expressed as the stoichiometric equivalent of pendimethalin, in or on grass forage...

Learning to be different: Acquired skills, social learning, frequency dependence, and environmental variation can cause behaviourally mediated foraging specializations

USGS Publications Warehouse

Tinker, M.T.; Mangel, M.; Estes, J.A.

2009-01-01

Question: How does the ability to improve foraging skills by learning, and to transfer that learned knowledge, affect the development of intra-population foraging specializations? Features of the model: We use both a state-dependent life-history model implemented by stochastic dynamic programming (SDPM) and an individual-based model (IBM) to capture the dynamic nature of behavioural preferences in feeding. Variables in the SDPM include energy reserves, skill levels, energy and handling time per single prey item, metabolic rate, the rates at which skills are learned and forgotten, the effect of skills on handling time, and the relationship between energy reserves and fitness. Additional variables in the IBM include the probability of successful weaning, the logistic dynamics of the prey species with stochastic recruitment, the intensity of top-down control of prey by predators, the mean and variance in skill levels of new recruits, and the extent to which learned Information can be transmitted via matrilineal social learning. Key range of variables: We explore the effects of approaching the time horizon in the SDPM, changing the extent to which skills can improve with experience, increasing the rates of learning or forgetting of skills, changing whether the learning curve is constant, accelerating (T-shaped) or decelerating ('r'-shaped), changing both mean and maximum possible energy reserves, changing metabolic costs of foraging, and changing the rate of encounter with prey. Conclusions: The model results show that the following factors increase the degree of prey specialization observed in a predator population: (1) Experience handling a prey type can substantially improve foraging skills for that prey. (2) There is limited ability to retain complex learned skills for multiple prey types. (3) The learning curve for acquiring new foraging skills is accelerating, or J-shaped. (4) The metabolic costs of foraging are high relative to available energy reserves. (5) Offspring can learn foraging skills from their mothers (matrilineal social learning). (6) Food abundance is limited, such that average individual energy reserves are low Additionally, the following factors increase the likelihood of alternative specializations co-occurring in a predator population: (1) The predator exerts effective top-down control of prey abundance, resulting in frequency-dependent dynamics. (2) There is stochastic Variation in prey population dynamics, but this Variation is neither too extreme in magnitude nor too 'slow' with respect to the time required for an individual forager to learn new foraging skills. For a given predator population, we deduce that the degree of specialization will be highest for those prey types requiring complex capture or handling skills, while prey species that are both profitable and easy to capture and handle will be included in the diet of all individuals. Frequency-dependent benefits of selecting alternative prey types, combined with the ability of foragers to improve their foraging skills by learning, and transmit learned skills to offspring, can result in behaviourally mediated foraging specialization, and also lead to the co-existence of alternative specializations. The extent of such specialization is predicted to be a variable trait, increasing in locations or years when intra-specific competition is high relative to inter-specific competition. ?? 2009 M. Tim Tinker.

The answer is blowing in the wind: free-flying honeybees can integrate visual and mechano-sensory inputs for making complex foraging decisions.

PubMed

Ravi, Sridhar; Garcia, Jair E; Wang, Chun; Dyer, Adrian G

2016-11-01

Bees navigate in complex environments using visual, olfactory and mechano-sensorial cues. In the lowest region of the atmosphere, the wind environment can be highly unsteady and bees employ fine motor-skills to enhance flight control. Recent work reveals sophisticated multi-modal processing of visual and olfactory channels by the bee brain to enhance foraging efficiency, but it currently remains unclear whether wind-induced mechano-sensory inputs are also integrated with visual information to facilitate decision making. Individual honeybees were trained in a linear flight arena with appetitive-aversive differential conditioning to use a context-setting cue of 3 m s -1 cross-wind direction to enable decisions about either a 'blue' or 'yellow' star stimulus being the correct alternative. Colour stimuli properties were mapped in bee-specific opponent-colour spaces to validate saliency, and to thus enable rapid reverse learning. Bees were able to integrate mechano-sensory and visual information to facilitate decisions that were significantly different to chance expectation after 35 learning trials. An independent group of bees were trained to find a single rewarding colour that was unrelated to the wind direction. In these trials, wind was not used as a context-setting cue and served only as a potential distracter in identifying the relevant rewarding visual stimuli. Comparison between respective groups shows that bees can learn to integrate visual and mechano-sensory information in a non-elemental fashion, revealing an unsuspected level of sensory processing in honeybees, and adding to the growing body of knowledge on the capacity of insect brains to use multi-modal sensory inputs in mediating foraging behaviour. © 2016. Published by The Company of Biologists Ltd.

Group foraging by a stream minnow: shoals or aggregations?

USGS Publications Warehouse

Freeman, Mary C.; Grossman, G.D.

1992-01-01

The importance of social attraction in the formation of foraging groups was examined for a stream-dwelling cyprinid, the rosyside dace, Clinostomus funduloides. Dace arrivals and departures at natural foraging sites were monitored and tested for (1) tendency of dace to travel in groups, and (2) dependency of arrival and departure rates on group size. Dace usually entered and departed foraging sites independently of each other. Group size usually affected neither arrival rate nor departure probability. Thus, attraction among dace appeared weak; foraging groups most often resulted from dace aggregating in preferred foraging sites. The strongest evidence of social attraction was during autumn, when dace departure probability often decreased with increasing group size, possibly in response to increased threat of predation by a seasonally occurring predator. Dace also rarely avoided conspecifics, except when an aggressive individual defended a foraging site. Otherwise, there was little evidence of exploitative competition among dace for drifting prey or of foraging benefits in groups, because group size usually did not affect individual feeding rates. These results suggest that the benefits of group foraging demonstrated under laboratory conditions in other studies may not always apply to field conditions.

Social reversal of immunosenescence in honey bee workers

PubMed Central

Amdam, Gro V.; Aase, Anne Lene T. O.; Seehuus, Siri-Christine; Fondrk, M. Kim; Norberg, Kari; Hartfelder, Klaus

2008-01-01

A striking example of immunosenescence is seen in the honey bee (Apis mellifera) worker caste. The bees’ age-associated transition from hive duties to more risky foraging activities is linked to a dramatic decline in immunity. Explicitly, it has been shown that an increase in the juvenile hormone (JH) level, which accompanies onset of foraging behavior, induces extensive hemocyte death through nuclear pycnosis. Here, we demonstrate that foragers that are forced to revert to hive-tasks show reversal of immunosenescence, i.e. a recovery of immunity with age. This recovery, which is triggered by a social manipulation, is accompanied by a drop in the endogenous JH titer and an increase in the hemolymph vitellogenin level. Vitellogenin is a zinc binding glycolipoprotein that has been implicated in the regulation of honey bee immune integrity. We also establish that worker immunosenescence is mediated by apoptosis, corroborating that reversal of immunosenescence emerges through proliferation of new cells. The results presented here, consequently, reveal a unique flexibility in honey bee immunity—a regulatory plasticity that may be of general biological interest. PMID:16169181

Effects of tidal cycles on shorebird distribution and foraging behaviour in a coastal tropical wetland: Insights for carrying capacity assessment

NASA Astrophysics Data System (ADS)

Fonseca, Juanita; Basso, Enzo; Serrano, David; Navedo, Juan G.

2017-11-01

Wetland loss has driven negative effects on biodiversity by a reduction in potential available habitats, directly impacting wetland-dependent species such as migratory shorebirds. At coastal areas where tidal cycles can restrict food access, the degree to which density of foraging birds is mediated by conspecific abundance or by the available areas is crucial to understanding patterns of bird distribution and wetland carrying capacity. We used the bathymetry of two sectors modeled with two numerical matrices to determine the availability of intertidal foraging areas in relation to tidal level (spring and neap tides), and this information was used to estimate shorebird density and foraging activity throughout the low-tide cycle in a tropical coastal lagoon in northwestern Mexico. Relative to spring tides, an 80% reduction in available foraging areas occurred during neap tides. Overall shorebird abundance was significantly reduced during neap tide periods, with differences between species. Densities of shorebirds increased during neap tides, particularly in one sector, and remained similar throughout the low-tide period (i.e. 4 h) either during spring or neap tides. Time spent foraging was consistently lower during neap-tides relative to spring-tides, especially for Long-billed curlew (44% reduction), Willet (37% reduction) and Black-necked stilt (29% reduction). These decreases in foraging activity when available habitats became reduced can hamper the opportunities of migratory shorebirds to reach their daily energy requirements to survive during the non-breeding season. This study shows that when intertidal habitats are severely reduced an important fraction of shorebird populations would probably be forced to find alternative areas to forage or increase foraging time during the night. Serving an essential function as top-predators, these results can have important implications on carrying capacity assessment for shorebirds at coastal wetlands.

Physiological effects of increased foraging effort in a small passerine.

PubMed

Yap, Kang Nian; Kim, Oh Run; Harris, Karilyn C; Williams, Tony D

2017-11-15

Foraging to obtain food, either for self-maintenance or at presumably elevated rates to provide for offspring, is thought to be an energetically demanding activity but one that is essential for fitness (higher reproductive success and survival). Nevertheless, the physiological mechanisms that allow some individuals to support higher foraging performance, and the mechanisms underlying costs of high workload, remain poorly understood. We experimentally manipulated foraging behaviour in zebra finches ( Taeniopygia guttata ) using the technique described by Koetsier and Verhulst (2011) Birds in the 'high foraging effort' (HF) group had to obtain food either while flying/hovering or by making repeated hops or jumps from the ground up to the feeder, behaviour typical of the extremely energetically expensive foraging mode observed in many free-living small passerines. HF birds made significantly more trips to the feeder per 10 min, whereas control birds spent more time (perched) at the feeder. Despite this marked change in foraging behaviour, we documented few short- or long-term effects of 'training' (3 days and 90 days of 'training', respectively) and some of these effects were sex specific. There were no effects of treatment on basal metabolic rate, haematocrit, haemoglobin or plasma glycerol, triglyceride and glucose levels, and masses of kidney, crop, large intestine, small intestine, gizzard and liver. HF females had higher masses of flight muscle, leg muscle, heart and lung compared with controls. In contrast, HF males had lower heart mass than controls and there were no differences for other organs. When both sexes were pooled, there were no effects of treatment on body composition. Finally, birds in the HF treatment group had higher levels of reactive oxygen metabolites (dROMs) and, consequently, although treatment did not affect total anti-oxidant capacity, birds in the HF treatment group had higher oxidative stress. © 2017. Published by The Company of Biologists Ltd.

40 CFR 180.481 - Prosulfuron; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., group 16, except rice, fodder 0.01 Grain, cereal, forage, fodder, and straw, group 16, except rice, forage 0.10 Grain, cereal, forage, fodder, and straw, group 16, except rice, hay 0.20 Grain, cereal, forage, fodder, and straw, group 16, except rice, straw 0.02 Grain, cereal, group 15, except rice 0.01 (b...

40 CFR 180.481 - Prosulfuron; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., group 16, except rice, fodder 0.01 Grain, cereal, forage, fodder, and straw, group 16, except rice, forage 0.10 Grain, cereal, forage, fodder, and straw, group 16, except rice, hay 0.20 Grain, cereal, forage, fodder, and straw, group 16, except rice, straw 0.02 Grain, cereal, group 15, except rice 0.01 (b...

Seasonal foraging patterns of forest-grazing Japanese Black heifers with increased plasma total antioxidant capacity.

PubMed

Haga, Satoshi; Nakano, Miwa; Nakao, Seiji; Hirano, Kiyoshi; Yamamoto, Yoshito; Sasaki, Hiroyuki; Ishizaki, Hiroshi

2016-02-01

Forest-grazing enables the intake of high total antioxidant capacity (TAC) plants that might be beneficial for the TAC status of cattle. This study evaluated the relation between the seasonal foraging patterns of forest-grazing Japanese Black (JB) heifers or the TAC levels in shrubs and trees and the changes of plasma TAC. We examined 12 JB heifers, four each of which were allocated to forest-grazing (F), pasture-grazing, and pen-housed groups. The plasma TAC level in F heifers on July 26, August 13, 30 and September 17 were significantly higher than those on April 27 and June 4 (P < 0.05). In F group, the mean rates of foraging frequency (FF) of shrubs and trees during July 5-8 and September 13-16 were much higher than that during May 31-June 3 (P < 0.05). The rate of FF of grass significantly decreased later in the season (P < 0.05). The mean TAC levels in these shrubs and trees were higher than those in grasses, concentrates, and timothy hay. Results suggest that an important factor in the increase of plasma TAC in forest-grazing cattle might be the increased foraging of TAC-rich shrubs and trees during summer-fall. © 2015 Japanese Society of Animal Science.

Stress-mediated Allee effects can cause the sudden collapse of honey bee colonies.

PubMed

Booton, Ross D; Iwasa, Yoh; Marshall, James A R; Childs, Dylan Z

2017-05-07

The recent rapid decline in global honey bee populations could have significant implications for ecological systems, economics and food security. No single cause of honey bee collapse has yet to be identified, although pesticides, mites and other pathogens have all been shown to have a sublethal effect. We present a model of a functioning bee hive and introduce external stress to investigate the impact on the regulatory processes of recruitment to the forager class, social inhibition and the laying rate of the queen. The model predicts that constant density-dependent stress acting through an Allee effect on the hive can result in sudden catastrophic switches in dynamical behaviour and the eventual collapse of the hive. The model proposes that around a critical point the hive undergoes a saddle-node bifurcation, and that a small increase in model parameters can have irreversible consequences for the entire hive. We predict that increased stress levels can be counteracted by a higher laying rate of the queen, lower levels of forager recruitment or lower levels of natural mortality of foragers, and that increasing social inhibition can not maintain the colony under high levels of stress. We lay the theoretical foundation for sudden honey bee collapse in order to facilitate further experimental and theoretical consideration. Copyright © 2017 Elsevier Ltd. All rights reserved.

7 CFR 407.13 - Group risk plan for forage.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 6 2013-01-01 2013-01-01 false Group risk plan for forage. 407.13 Section 407.13..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.13 Group risk plan for forage. The provisions of the Group Risk Plan for Forage for the 2000 and succeeding crop years are as follows: 1...

7 CFR 407.13 - Group risk plan for forage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 6 2012-01-01 2012-01-01 false Group risk plan for forage. 407.13 Section 407.13..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.13 Group risk plan for forage. The provisions of the Group Risk Plan for Forage for the 2000 and succeeding crop years are as follows: 1...

7 CFR 407.13 - Group risk plan for forage.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Group risk plan for forage. 407.13 Section 407.13..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.13 Group risk plan for forage. The provisions of the Group Risk Plan for Forage for the 2000 and succeeding crop years are as follows: 1...

Fisheries research and monitoring activities of the Lake Erie Biological Station, 2015

USGS Publications Warehouse

Bodamer Scarbro, Betsy L.; Edwards, W.H.; Kocovsky, Patrick M.; Kraus, Richard T.; Rogers, M. R.; Schoonyan, A. L.; Stewart, T. R.

2016-01-01

In 2015, the U.S. Geological Survey’s (USGS) Lake Erie Biological Station (LEBS) successfully completed large vessel surveys in all three of Lake Erie’s basins. Lake Erie Biological Station’s primary vessel surveys included the Western Basin Forage Fish Assessment and East Harbor Fish Community Assessment as well as contributing to the cooperative multi-agency Central Basin Hydroacoustics Assessment, the Eastern Basin Coldwater Community Assessment, and Lower Trophic Level Assessment (see Forage and Coldwater Task Group reports). In 2015, LEBS also initiated a Lake Erie Central Basin Trawling survey in response to the need for forage fish data from Management Unit 3 (as defined by the Yellow Perch Task Group). Results from these surveys contribute to Lake Erie Committee Fish Community Goals and Objectives. Our 2015 vessel operations were initiated in early April and continued into late November. During this time, crews of the R/V Muskie and R/V Bowfin deployed 121 bottom trawls covering 83.2 ha of lake-bottom and catching 105,600 fish totaling 4,065 kg during four separate trawl surveys in the western and central basins of Lake Erie. We deployed and lifted 9.5 km of gillnet, which caught an additional 805 fish, 100 (337 kg) of which were the native coldwater predators Lake Trout, Burbot, and Lake Whitefish (these data are reported in the 2016 Coldwater Task Group report). We also conducted 317 km of hydroacoustic survey transects (reported in the 2016 Forage Task Group report), collected 114 lower trophic (i.e. zooplankton and benthos) samples, and obtained 216 water quality observations (e.g., temperature profiles, and water samples). The LEBS also assisted CLC member agencies with the maintenance and expansion of GLATOS throughout all three Lake Erie sub-basins. Within the following report sections, we describe results from three trawl surveys – the spring and autumn Western Basin Forage Fish Assessment and the East Harbor Forage Fish Assessment – and the Lower Trophic Level Assessment conducted in 2015, and examine trends in the fish community structure and trophic status of Lake Erie. Results of our central basin trawl survey are reported in the 2016 Yellow Perch Task Group report.

Differing foraging strategies influence mercury (Hg) exposure in an Antarctic penguin community.

PubMed

Polito, Michael J; Brasso, Rebecka L; Trivelpiece, Wayne Z; Karnovsky, Nina; Patterson, William P; Emslie, Steven D

2016-11-01

Seabirds are ideal model organisms to track mercury (Hg) through marine food webs as they are long-lived, broadly distributed, and are susceptible to biomagnification due to foraging at relatively high trophic levels. However, using these species as biomonitors requires a solid understanding of the degree of species, sexual and age-specific variation in foraging behaviors which act to mediate their dietary exposure to Hg. We combined stomach content analysis along with Hg and stable isotope analyses of blood, feathers and common prey items to help explain inter and intra-specific patterns of dietary Hg exposure across three sympatric Pygoscelis penguin species commonly used as biomonitors of Hg availability in the Antarctic marine ecosystem. We found that penguin tissue Hg concentrations differed across species, between adults and juveniles, but not between sexes. While all three penguins species diets were dominated by Antarctic krill (Euphausia superba) and to a lesser extent fish, stable isotope based proxies of relative trophic level and krill consumption could not by itself sufficiently explain the observed patterns of inter and intra-specific variation in Hg. However, integrating isotopic approaches with stomach content analysis allowed us to identify the relatively higher risk of Hg exposure for penguins foraging on mesopelagic prey relative to congeners targeting epipelagic or benthic prey species. When possible, future seabird biomonitoring studies should seek to combine isotopic approaches with other, independent measures of foraging behavior to better account for the confounding effects of inter and intra-specific variation on dietary Hg exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Honey Bee Inhibitory Signaling Is Tuned to Threat Severity and Can Act as a Colony Alarm Signal

PubMed Central

Li, Xinyu; Liu, Xiwen; Wang, Chao; Li, Jianjun

2016-01-01

Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world’s largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon foragers and nests of the Asian honey bee, Apis cerana. We attacked foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that, like Apis mellifera, A. cerana possesses a vibrational “stop signal,” which can be triggered by predator attacks upon foragers and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS large hornet) had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS small hornet) and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS nest) were produced by foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon foragers (SS forager). Unlike SS forager, SS nest were targeted at dancing and non-dancing foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by the bee alarm pheromone and live hornet presence to heat-ball the hornet. In A. cerana, sophisticated recruitment communication that encodes food location, the waggle dance, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level. PMID:27014876

Honey Bee Inhibitory Signaling Is Tuned to Threat Severity and Can Act as a Colony Alarm Signal.

PubMed

Tan, Ken; Dong, Shihao; Li, Xinyu; Liu, Xiwen; Wang, Chao; Li, Jianjun; Nieh, James C

2016-03-01

Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world's largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon foragers and nests of the Asian honey bee, Apis cerana. We attacked foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that, like Apis mellifera, A. cerana possesses a vibrational "stop signal," which can be triggered by predator attacks upon foragers and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS large hornet) had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS small hornet) and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS nest) were produced by foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon foragers (SS forager). Unlike SS forager, SS nest were targeted at dancing and non-dancing foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by the bee alarm pheromone and live hornet presence to heat-ball the hornet. In A. cerana, sophisticated recruitment communication that encodes food location, the waggle dance, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level.

The Organization of Foraging in the Fire Ant, Solenopsis invicta

PubMed Central

Tschinkel, Walter R.

2011-01-01

Although natural selection in ants acts most strongly at the colony, or superorganismal level, foraging patterns have rarely been studied at that level, focusing instead on the behavior of individual foragers or groups of foragers. The experiments and observations in this paper reveal in broad strokes how colonies of the fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), allocate their available labor to foraging, how they disperse that force within their territory, and how this force changes with colony size, season and worker age. Territory area is positively related to colony size and the number of foragers, more so during the spring than fall. Changes of colony size and territory area are driven by seasonal variation of sexual and worker production, which in turn drive seasonal variation of worker age-distribution. During spring sexual production, colonies shrink because worker production falls below replacement. This loss is proportional to colony size, causing forager density in the spring to be negatively related to colony and territory size. In the fall, colonies emphasize worker production, bringing colony size back up. However, because smaller colonies curtailed spring worker production less than larger ones, their fall forager populations are proportionally greater, causing them to gain territory at the expense of large colonies. Much variation of territory area remains unexplained and can probably be attributed to pressure from neighboring colonies. Boundaries between territories are characterized by “no ants' zones” mostly devoid of fire ants. The forager population can be divided into a younger group of recruitable workers that wait for scouts to activate them to help retrieve large food finds. About one-third of the recruits wait near openings in the foraging tunnels that underlie the entire territory, while two-thirds wait in the nest. Recruitment to food is initially very rapid and local from the foraging tunnels, while sustained recruitment gradually involves the recruits waiting in the nest. As recruits age, they become scouts searching for food on the surface, and die about two weeks later. Foraging tunnels decrease in cross-sectional area with distance from the nest, in keeping with the gradual bleeding off of workers to the surface with distance. Foragers lack route-faithfulness, and having been marked and released at one point within the territory, they can be recaptured at any other point a day later. The size of the territory actually occupied may be limited during dry weather, resulting in very large no-ants' zones. PMID:21529150

Direct fitness benefits and kinship of social foraging groups in an Old World tropical babbler

USGS Publications Warehouse

Kaiser, Sara A.; Martin, Thomas E.; Oteyza, Juan C.; Armstad, Connor E.; Fleischer, Robert C.

2018-01-01

Molecular studies have revealed that social groups composed mainly of nonrelatives may be widespread in group-living vertebrates, but the benefits favoring such sociality are not well understood. In the Old World, birds often form conspecific foraging groups that are maintained year-round and offspring usually disperse to other social groups. We tested the hypothesis that nonbreeding group members are largely unrelated and gain direct fitness benefits through breeding opportunities (males) and brood parasitism (females) in the tropical gray-throated babbler, Stachyris nigriceps, in Malaysian Borneo. Babblers foraged in social groups containing one or more breeding pairs (median = 8 group members of equal sex ratio), but group members rarely assisted with breeding (9% of 67 breeding pairs had a third helper; exhibiting facultative cooperative breeding). Although 20% of 266 group member dyads were first-order relatives of one or both members of the breeding pairs, 80% were unrelated. Male group members gained direct fitness benefits through extrapair and extra-group paternity (25% of 73 offspring), which was independent of their relatedness to the breeding pair and increased with decreasing group size. In contrast, females did not gain direct fitness benefits through brood parasitism. The low levels of relatedness and helping in social groups suggest that most group members do not gain indirect fitness benefits by helping to raise unrelated offspring. These findings highlight the importance of examining benefits of sociality for unrelated individuals that largely do not help and broaden the direct fitness benefits of group foraging beyond assumed survival benefits.

Group foraging increases foraging efficiency in a piscivorous diver, the African penguin

PubMed Central

McGeorge, Cuan; Ginsberg, Samuel; Pichegru, Lorien; Pistorius, Pierre A.

2017-01-01

Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders. Individuals pursued both solitary as well as schooling pelagic fish, and demonstrated independent as well as group foraging behaviour. The most profitable foraging involved herding of fish schools upwards during the ascent phase of a dive where most catches constituted depolarized fish. Catch-per-unit-effort was significantly improved when targeting fish schools as opposed to single fish, especially when foraging in groups. In contrast to more generalist penguin species, African penguins appear to have evolved specialist hunting strategies closely linked to their primary reliance on schooling pelagic fish. The specialist nature of the observed hunting strategies further limits the survival potential of this species if Allee effects reduce group size-related foraging efficiency. This is likely to be exacerbated by diminishing fish stocks due to resource competition and environmental change. PMID:28989785

Echolocation click rates and behavior of foraging Hawaiian spinner dolphins

NASA Astrophysics Data System (ADS)

Benoit-Bird, Kelly J.; Au, Whitlow W. L.

2004-05-01

Groups of spinner dolphins work together to actively aggregate small animals in the deep-scattering layer that serve as their prey. Detailed information on dolphin foraging behavior, obtained with a 200-kHz multibeam sonar (Simrad MS2000), made it possible to correlate echolocation and foraging. Fifty-six groups of spinner dolphins foraging at night within a midwater micronekton sound-scattering layer were observed with the sonar. During sonar surveys, the rates of whistles and echolocation clicks were measured using four hydrophones at 6-m depth intervals. Significant differences in click rates were found between depths and between the different stages of foraging. Groups of foraging dolphins ranged in size from 16 to 28 dolphins. Click rates were not significantly affected by the number of dolphins in a foraging group. Contrary to initial predictions, click rates were relatively low when sonar data indicated that pairs of dolphins were actively feeding. Highest echolocation rates occurred within the scattering layer, during transitions between foraging states. Whistles were only detected when dolphins were not in a foraging formation and when animals were surfacing. This suggests clicks may be used directly or indirectly to cue group movement during foraging.

Effects of Liming on Forage Availability and Nutrient Content in a Forest Impacted by Acid Rain

PubMed Central

Pabian, Sarah E.; Ermer, Nathan M.; Tzilkowski, Walter M.; Brittingham, Margaret C.

2012-01-01

Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer. PMID:22761890

Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

PubMed

Pabian, Sarah E; Ermer, Nathan M; Tzilkowski, Walter M; Brittingham, Margaret C

2012-01-01

Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Emergence of leadership in a robotic fish group under diverging individual personality traits.

PubMed

Wang, Chen; Chen, Xiaojie; Xie, Guangming; Cao, Ming

2017-05-01

Variations of individual's personality traits have been identified before as one of the possible mechanisms for the emergence of leadership in an interactive collective, which may lead to benefits for the group as a whole. Complementing the large number of existing literatures on using simulation models to study leadership, we use biomimetic robotic fish to gain insight into how the fish's behaviours evolve under the influence of the physical hydrodynamics. In particular, we focus in this paper on understanding how robotic fish's personality traits affect the emergence of an effective leading fish in repeated robotic foraging tasks when the robotic fish's strategies, to push or not to push the obstacle in its foraging path, are updated over time following an evolutionary game set-up. We further show that the robotic fish's personality traits diverge when the group carries out difficult foraging tasks in our experiments, and self-organization takes place to help the group to adapt to the level of difficulties of the tasks without inter-individual communication.

Evaluating Energy Flows Through Jellyfish and Forage Fish and the Effects of Fishing on the Northern Humboldt Current Ecosystem

NASA Astrophysics Data System (ADS)

Chiaverano, L.; Robinson, K. L.; Ruzicka, J.; Quiñones, J.; Tam, J.; Acha, M.; Graham, W. M.; Brodeur, R.; Decker, M. B.; Hernandez, F., Jr.; Leaf, R.; Mianzan, H.; Uye, S. I.

2016-02-01

Increases in the frequency of jellyfish mass occurrences in a number of coastal areas around the globe have intensified concerns that some ecosystems are becoming "jellyfish-dominated". Gelatinous planktivores not only compete with forage fish for food, but also feed on fish eggs and larvae. When jellyfish abundance is high, the fraction of the energy and the efficiency at which it is transferred upwards in the food web are reduced compared with times when fish are dominant. Hence, ecosystems supporting major forage fish fisheries are the most likely to experience fish-to-jellyfish shifts due to the harvest pressure on mid-trophic planktivores. Although forage fish-jellyfish replacement cycles have been detected in recent decades in some productive, coastal ecosystems (e.g. Gulf of Mexico, Northern California Current), jellyfish are typically not included in ecosystem-based fisheries management (EBFM) production models. Here we explored the roles of jellyfish and forage fish as trophic energy transfer pathways to higher trophic levels in the Northern Humboldt Current (NHC) ecosystem, one of the most productive ecosystems in the world. A trophic network model with 33 functional groups was developed using ECOPATH and transformed to an end-to-end model using ECOTRAN techniques to map food web energy flows. Predicted, relative changes in functional group productivity were analyzed in simulations with varying forage fish consumption rates, jellyfish consumption rates, and forage fish harvest rates in a suite of static, alternative-energy-demand scenarios. Our modeling efforts will not only improve EBFM of forage fish and their predators in the NHC ecosystem, but also increase our understanding of trophic interactions between forage fish and large jellyfish, an important, but overlooked component in most ecosystem models to date.

40 CFR 180.227 - Dicamba; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... removed 0.04 Corn, sweet, stover 0.50 Cotton, undelinted seed 0.2 Grass, forage, fodder and hay, group 17, forage 125.0 Grass, forage, fodder and hay, group 17, hay 200.0 Millet, proso, forage 90.0 Millet, proso...

A mechanism that maintains alternative life histories in a loggerhead sea turtle population.

PubMed

Hatase, Hideo; Omuta, Kazuyoshi; Tsukamoto, Katsumi

2013-11-01

Intrapopulation variation in habitat use is commonly seen among mobile animals, yet the mechanisms maintaining it have rarely been researched among untrackable species. To investigate how alternative life histories are maintained in a population of the loggerhead sea turtle (Caretta caretta), cumulative reproductive output was evaluated and compared between small planktivores inhabiting oceanic areas (with water depths > 200 m) and large benthivores inhabiting neritic areas (depths < 200 m) that sympatrically nested at Yakushima Island, Japan, from 1986 to 2011. In total, 362 nesting females sampled in three different years were classified into the two foraging groups based on stable isotope ratios in egg yolks. There were significant differences between the two foraging groups in most recorded life history parameters (clutch size, clutch frequency, breeding frequency, and remigration intervals), with the exception of emergence success. We did not find evidence of life history trade-offs, nor age-related changes in fecundity. Over the 26-year study period, we calculated a 2.4-fold greater reproductive output for neritic foragers than for oceanic ones, accounting for breeding and clutch frequency. Temporal consistencies in stable isotope ratios and remigration intervals within females suggested that female Japanese loggerheads show fidelity to respective foraging habitats throughout the adult stage. The large difference in productivity between the two groups was unlikely to be offset by the difference in survival during the period from aboveground emergence to first reproduction, suggesting that oceanic foragers have a lower level of fitness than neritic ones. Together with an absence of genetic structure between foraging groups, we infer that alternative life histories in a loggerhead turtle population are maintained by a conditional strategy.

Hemocyte-mediated phagocytosis differs between honey bee (Apis mellifera) worker castes

PubMed Central

Salmela, Heli; Amdam, Gro Vang; Münch, Daniel

2017-01-01

Honey bees as other insects rely on the innate immune system for protection against diseases. The innate immune system includes the circulating hemocytes (immune cells) that clear pathogens from hemolymph (blood) by phagocytosis, nodulation or encapsulation. Honey bee hemocyte numbers have been linked to hemolymph levels of vitellogenin. Vitellogenin is a multifunctional protein with immune-supportive functions identified in a range of species, including the honey bee. Hemocyte numbers can increase via mitosis, and this recruitment process can be important for immune system function and maintenance. Here, we tested if hemocyte mediated phagocytosis differs among the physiologically different honey bee worker castes (nurses, foragers and winter bees), and study possible interactions with vitellogenin and hemocyte recruitment. To this end, we adapted phagocytosis assays, which—together with confocal microscopy and flow cytometry—allow qualitative and quantitative assessment of hemocyte performance. We found that nurses are more efficient in phagocytic uptake than both foragers and winter bees. We detected vitellogenin within the hemocytes, and found that winter bees have the highest numbers of vitellogenin-positive hemocytes. Connections between phagocytosis, hemocyte-vitellogenin and mitosis were worker caste dependent. Our results demonstrate that the phagocytic performance of immune cells differs significantly between honey bee worker castes, and support increased immune competence in nurses as compared to forager bees. Our data, moreover, provides support for roles of vitellogenin in hemocyte activity. PMID:28877227

Hemocyte-mediated phagocytosis differs between honey bee (Apis mellifera) worker castes.

PubMed

Hystad, Eva Marit; Salmela, Heli; Amdam, Gro Vang; Münch, Daniel

2017-01-01

Honey bees as other insects rely on the innate immune system for protection against diseases. The innate immune system includes the circulating hemocytes (immune cells) that clear pathogens from hemolymph (blood) by phagocytosis, nodulation or encapsulation. Honey bee hemocyte numbers have been linked to hemolymph levels of vitellogenin. Vitellogenin is a multifunctional protein with immune-supportive functions identified in a range of species, including the honey bee. Hemocyte numbers can increase via mitosis, and this recruitment process can be important for immune system function and maintenance. Here, we tested if hemocyte mediated phagocytosis differs among the physiologically different honey bee worker castes (nurses, foragers and winter bees), and study possible interactions with vitellogenin and hemocyte recruitment. To this end, we adapted phagocytosis assays, which-together with confocal microscopy and flow cytometry-allow qualitative and quantitative assessment of hemocyte performance. We found that nurses are more efficient in phagocytic uptake than both foragers and winter bees. We detected vitellogenin within the hemocytes, and found that winter bees have the highest numbers of vitellogenin-positive hemocytes. Connections between phagocytosis, hemocyte-vitellogenin and mitosis were worker caste dependent. Our results demonstrate that the phagocytic performance of immune cells differs significantly between honey bee worker castes, and support increased immune competence in nurses as compared to forager bees. Our data, moreover, provides support for roles of vitellogenin in hemocyte activity.

Octopamine influences honey bee foraging preference.

PubMed

Giray, Tugrul; Galindo-Cardona, Alberto; Oskay, Devrim

2007-07-01

Colony condition and differences in individual preferences influence forage type collected by bees. Physiological bases for the changing preferences of individual foragers are just beginning to be examined. Recently, for honey bees octopamine is shown to influence age at onset of foraging and probability of dance for rewards. However, octopamine has not been causally linked with foraging preference in the field. We tested the hypothesis that changes in octopamine may alter forage type (preference hypothesis). We treated identified foragers orally with octopamine or its immediate precursor, tyramine, or sucrose syrup (control). Octopamine-treated foragers switched type of material collected; control bees did not. Tyramine group results were not different from the control group. In addition, sugar concentrations of nectar collected by foragers after octopamine treatment were lower than before treatment, indicating change in preference. In contrast, before and after nectar concentrations for bees in the control group were similar. These results, taken together, support the preference hypothesis.

Air pollutants degrade floral scents and increase insect foraging times

NASA Astrophysics Data System (ADS)

Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.

2016-09-01

Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

Social foraging with partial (public) information.

PubMed

Mann, Ofri; Kiflawi, Moshe

2014-10-21

Group foragers can utilize public information to better estimate patch quality and arrive at more efficient patch-departure rules. However, acquiring such information may come at a cost; e.g. reduced search efficiency. We present a Bayesian group-foraging model in which social foragers do not require full awareness of their companions' foraging success; only of their number. In our model, patch departure is based on direct estimates of the number of remaining items. This is achieved by considering all likely combinations of initial patch-quality and group foraging-success; given the individual forager's experience within the patch. Slower rates of information-acquisition by our 'partially-aware' foragers lead them to over-utilize poor patches; more than fully-aware foragers. However, our model suggests that the ensuing loss in long-term intake-rates can be matched by a relatively low cost to the acquisition of full public information. In other words, we suggest that group-size offers sufficient information for optimal patch utilization by social foragers. We suggest, also, that our model is applicable to other situations where resources undergo 'background depletion', which is coincident but independent of the consumer's own utilization. Copyright © 2014 Elsevier Ltd. All rights reserved.

Eye Size, Fovea, and Foraging Ecology in Accipitriform Raptors.

PubMed

Potier, Simon; Mitkus, Mindaugas; Bonadonna, Francesco; Duriez, Olivier; Isard, Pierre-François; Dulaurent, Thomas; Mentek, Marielle; Kelber, Almut

2017-01-01

Birds with larger eyes are predicted to have higher spatial resolution because of their larger retinal image. Raptors are well known for their acute vision, mediated by their deep central fovea. Because foraging strategies may demand specific visual adaptations, eye size and fovea may differ between species with different foraging ecology. We tested whether predators (actively hunting mobile prey) and carrion eaters (eating dead prey) from the order Accipitriformes differ in eye size, foveal depth, and retinal thickness using spectral domain optical coherence tomography and comparative phylogenetic methods. We found that (1) all studied predators (except one) had a central and a temporal fovea, but all carrion eaters had only the central fovea; (2) eye size scaled with body mass both in predators and carrion eaters; (3) predators had larger eyes relative to body mass and a thicker retina at the edge of the fovea than carrion eaters, but there was no difference in the depth of the central fovea between the groups. Finally, we found that (4) larger eyes generally had a deeper central fovea. These results suggest that the visual system of raptors within the order Accipitriformes may be highly adapted to the foraging strategy, except for the foveal depth, which seems mostly dependent upon the eye size. © 2017 S. Karger AG, Basel.

Task Allocation of Wasps Governed by Common Stomach: A Model Based on Electric Circuits

PubMed Central

2016-01-01

Simple regulatory mechanisms based on the idea of the saturable ‘common stomach’ can control the regulation of construction behavior and colony-level responses to environmental perturbations in Metapolybia wasp societies. We mapped the different task groups to mutual inductance electrical circuits and used Kirchoff’s basic voltage laws to build a model that uses master equations from physics, yet is able to provide strong predictions for this complex biological phenomenon. Similar to real colonies, independently of the initial conditions, the system shortly sets into an equilibrium, which provides optimal task allocation for a steady construction, depending on the influx of accessible water. The system is very flexible and in the case of perturbations, it reallocates its workforce and adapts to the new situation with different equilibrium levels. Similar to the finding of field studies, decreasing any task groups caused decrease of construction; increasing or decreasing water inflow stimulated or reduced the work of other task groups while triggering compensatory behavior in water foragers. We also showed that only well connected circuits are able to produce adequate construction and this agrees with the finding that this type of task partitioning only exists in larger colonies. Studying the buffer properties of the common stomach and its effect on the foragers revealed that it provides stronger negative feedback to the water foragers, while the connection between the pulp foragers and the common stomach has a strong fixed-point attractor, as evidenced by the dissipative trajectory. PMID:27861633

Identifying preferred habitats of samango monkeys (Cercopithecus (nictitans) mitis erythrarchus) through patch use.

PubMed

Emerson, Sara E; Brown, Joel S

2013-11-01

To examine habitat preferences of two groups of samango monkeys (Cercopithecus (nictitans) mitis erythrarchus) in the Soutpansberg, South Africa, we used experimental food patches in fragments of tall forest and in bordering secondary growth short forest. Additionally, to test for the impacts of group cohesion and movement on habitat use, we tested for the interaction of space and time in our analyses of foraging intensity in the experimental food patches placed throughout the home ranges of the two groups. We expected the monkeys to harvest the most from patches in tall forest habitats and the least from patches in short forest. Further, because the monkeys move through their habitats in groups, we expected to see group cohesion effects illustrated by daily spatial variation in the monkeys’ use of widespread foraging grids. In the forest height experiments, the two groups differed in their foraging responses, with 8% greater foraging overall for one group. However, forest height did not significantly impact foraging in either group, meaning that, given feeding opportunities, samango monkeys are able to utilise secondary growth forest. For one group, missed opportunity costs of staying with the group appeared through the statistical interaction of day with foraging location (the monkeys did not always spread out to take advantage of all available food patches). In several subsequent experiments in widespread grids, significant daily spatial variation in foraging occurred, pointing to spatial cohesion during group movement as likely being an important predictor of habitat use. For an individual social forager, staying with the group may be more important than habitat type in driving habitat selection.

Group choice: the ideal free distribution of human social behavior.

PubMed

Kraft, J R; Baum, W M

2001-07-01

Group choice refers to the distribution of group members between two choice alternatives over time. The ideal free distribution (IFD), an optimal foraging model from behavioral ecology, predicts that the ratio of foragers at two resource sites should equal the ratio of obtained resources, a prediction that is formally analogous to the matching law of individual choice, except that group choice is a social phenomenon. Two experiments investigated the usefulness of IFD analyses of human group choice and individual-based explanations that might account for the group-level events. Instead of nonhuman animals foraging at two sites for resources, a group of humans chose blue and red cards to receive points that could earn cash prizes. The groups chose blue and red cards in ratios in positive relation to the ratios of points associated with the cards. When group choice ratios and point ratios were plotted on logarithmic coordinates and fitted with regression lines, the slopes (i.e., sensitivity measures) approached 1.0 but tended to fall short of it (i.e., undermatching), with little bias and little unaccounted for variance. These experiments demonstrate that an IFD analysis of group choice is possible and useful, and suggest that group choice may be explained by the individual members' tendency to optimize reinforcement.

Transgenic Alfalfa Plants Expressing the Sweetpotato Orange Gene Exhibit Enhanced Abiotic Stress Tolerance

PubMed Central

Wang, Zhi; Ke, Qingbo; Kim, Myoung Duck; Kim, Sun Ha; Ji, Chang Yoon; Jeong, Jae Cheol; Lee, Haeng-Soon; Park, Woo Sung; Ahn, Mi-Jeong; Li, Hongbing; Xu, Bingcheng; Deng, Xiping; Lee, Sang-Hoon; Lim, Yong Pyo; Kwak, Sang-Soo

2015-01-01

Alfalfa (Medicago sativa L.), a perennial forage crop with high nutritional content, is widely distributed in various environments worldwide. We recently demonstrated that the sweetpotato Orange gene (IbOr) is involved in increasing carotenoid accumulation and enhancing resistance to multiple abiotic stresses. In this study, in an effort to improve the nutritional quality and environmental stress tolerance of alfalfa, we transferred the IbOr gene into alfalfa (cv. Xinjiang Daye) under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter through Agrobacterium tumefaciens-mediated transformation. Among the 11 transgenic alfalfa lines (referred to as SOR plants), three lines (SOR2, SOR3, and SOR8) selected based on their IbOr transcript levels were examined for their tolerance to methyl viologen (MV)-induced oxidative stress in a leaf disc assay. The SOR plants exhibited less damage in response to MV-mediated oxidative stress and salt stress than non-transgenic plants. The SOR plants also exhibited enhanced tolerance to drought stress, along with higher total carotenoid levels. The results suggest that SOR alfalfa plants would be useful as forage crops with improved nutritional value and increased tolerance to multiple abiotic stresses, which would enhance the development of sustainable agriculture on marginal lands. PMID:25946429

Transgenic alfalfa plants expressing the sweetpotato Orange gene exhibit enhanced abiotic stress tolerance.

PubMed

Wang, Zhi; Ke, Qingbo; Kim, Myoung Duck; Kim, Sun Ha; Ji, Chang Yoon; Jeong, Jae Cheol; Lee, Haeng-Soon; Park, Woo Sung; Ahn, Mi-Jeong; Li, Hongbing; Xu, Bingcheng; Deng, Xiping; Lee, Sang-Hoon; Lim, Yong Pyo; Kwak, Sang-Soo

2015-01-01

Alfalfa (Medicago sativa L.), a perennial forage crop with high nutritional content, is widely distributed in various environments worldwide. We recently demonstrated that the sweetpotato Orange gene (IbOr) is involved in increasing carotenoid accumulation and enhancing resistance to multiple abiotic stresses. In this study, in an effort to improve the nutritional quality and environmental stress tolerance of alfalfa, we transferred the IbOr gene into alfalfa (cv. Xinjiang Daye) under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter through Agrobacterium tumefaciens-mediated transformation. Among the 11 transgenic alfalfa lines (referred to as SOR plants), three lines (SOR2, SOR3, and SOR8) selected based on their IbOr transcript levels were examined for their tolerance to methyl viologen (MV)-induced oxidative stress in a leaf disc assay. The SOR plants exhibited less damage in response to MV-mediated oxidative stress and salt stress than non-transgenic plants. The SOR plants also exhibited enhanced tolerance to drought stress, along with higher total carotenoid levels. The results suggest that SOR alfalfa plants would be useful as forage crops with improved nutritional value and increased tolerance to multiple abiotic stresses, which would enhance the development of sustainable agriculture on marginal lands.

Seasonal sexual segregation in two Thalassarche albatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?

PubMed

Phillips, R A; Silk, J R D; Phalan, B; Catry, P; Croxall, J P

2004-06-22

Sexual segregation by micro- or macrohabitat is common in birds, and usually attributed to size-mediated dominance and exclusion of females by larger males, trophic niche divergence or reproductive role specialization. Our study of black-browed albatrosses, Thalassarche melanophrys, and grey-headed albatrosses, T. chrysostoma, revealed an exceptional degree of sexual segregation during incubation, with largely mutually exclusive core foraging ranges for each sex in both species. Spatial segregation was not apparent during brood-guard or post-guard chick rearing, when adults are constrained to feed close to colonies, providing no evidence for dominance-related competitive exclusion at the macrohabitat level. A comprehensive morphometric comparison indicated considerable species and sexual dimorphism in wing area and wing loading that corresponded, both within and between species, to broad-scale habitat preferences relating to wind strength. We suggest that seasonal sexual segregation in these two species is attributable to niche divergence mediated by differences in flight performance. Such sexual segregation may also have implications for conservation in relation to sex-specific overlap with commercial fisheries.

Laser-induced Breakdown Spectroscopy used to Detect Endophyte-mediated Accumulation of Metals by Tall Fescue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madhavi Z; Stewart, Arthur J; Gwinn, Dr. Kimberley

Laser-induced breakdown spectroscopy was used to determine the impact of endophyte (Neotyphodium sp.) infection on elemental composition of tall fescue (Festuca arundinacea). Leaf material from endophyte-infected (E+) and endophyte-free (E-) tall fescue populations in established plots was examined. Leaf-tissue digestates were also tested for metals, by ICP-MS. Seven of eleven metals (Ca, Mg, Fe, Mn, Cu, Ni and Zn) were measured by both techniques at concentrations great enough to reliably compare. Mg, Zn, and Cd, a toxic metal that can be present in forage, were readily detected by LIBS, even though Cd concentrations in the plants were below levels typicallymore » achieved using ICP-MS detection. Implications of these results for research on forage analysis and phytoremediation are discussed.« less

Evidence for acoustic communication among bottom foraging humpback whales

PubMed Central

Parks, Susan E.; Cusano, Dana A.; Stimpert, Alison K.; Weinrich, Mason T.; Friedlaender, Ari S.; Wiley, David N.

2014-01-01

Humpback whales (Megaptera novaeangliae), a mysticete with a cosmopolitan distribution, demonstrate marked behavioural plasticity. Recent studies show evidence of social learning in the transmission of specific population level traits ranging from complex singing to stereotyped prey capturing behaviour. Humpback whales have been observed to employ group foraging techniques, however details on how individuals coordinate behaviour in these groups is challenging to obtain. This study investigates the role of a novel broadband patterned pulsed sound produced by humpback whales engaged in bottom-feeding behaviours, referred to here as a ‘paired burst' sound. Data collected from 56 archival acoustic tag deployments were investigated to determine the functional significance of these signals. Paired burst sound production was associated exclusively with bottom feeding under low-light conditions, predominantly with evidence of associated conspecifics nearby suggesting that the sound likely serves either as a communicative signal to conspecifics, a signal to affect prey behaviour, or possibly both. This study provides additional evidence for individual variation and phenotypic plasticity of foraging behaviours in humpback whales and provides important evidence for the use of acoustic signals among foraging individuals in this species. PMID:25512188

Evidence for acoustic communication among bottom foraging humpback whales.

PubMed

Parks, Susan E; Cusano, Dana A; Stimpert, Alison K; Weinrich, Mason T; Friedlaender, Ari S; Wiley, David N

2014-12-16

Humpback whales (Megaptera novaeangliae), a mysticete with a cosmopolitan distribution, demonstrate marked behavioural plasticity. Recent studies show evidence of social learning in the transmission of specific population level traits ranging from complex singing to stereotyped prey capturing behaviour. Humpback whales have been observed to employ group foraging techniques, however details on how individuals coordinate behaviour in these groups is challenging to obtain. This study investigates the role of a novel broadband patterned pulsed sound produced by humpback whales engaged in bottom-feeding behaviours, referred to here as a 'paired burst' sound. Data collected from 56 archival acoustic tag deployments were investigated to determine the functional significance of these signals. Paired burst sound production was associated exclusively with bottom feeding under low-light conditions, predominantly with evidence of associated conspecifics nearby suggesting that the sound likely serves either as a communicative signal to conspecifics, a signal to affect prey behaviour, or possibly both. This study provides additional evidence for individual variation and phenotypic plasticity of foraging behaviours in humpback whales and provides important evidence for the use of acoustic signals among foraging individuals in this species.

40 CFR 180.451 - Tribenuron methyl; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... raw agricultural commodities: Commodity Parts per million Grass, forage, fodder and hay, group 17, except bermudagrass; forage 0.10 Grass, forage, fodder and hay, group 17, except bermudagrass; hay 0.10...

40 CFR 180.451 - Tribenuron methyl; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... raw agricultural commodities: Commodity Parts per million Grass, forage, fodder and hay, group 17, except bermudagrass; forage 0.10 Grass, forage, fodder and hay, group 17, except bermudagrass; hay 0.10...

Identifying preferred habitats of samango monkeys (Cercopithecus (nictitans) mitis, erythrarchus) through patch use.

PubMed

Emerson, Sara E; Brown, Joel S

2013-10-26

To examine habitat preferences of two groups of samango monkeys (Cercopithecus (nictitans) mitis erythrarchus) in the Soutpansberg, South Africa, we used experimental food patches in fragments of tall forest and in bordering secondary growth short forest. Additionally, to test for the impacts of group cohesion and movement on habitat use, we tested for the interaction of space and time in our analyses of foraging intensity in the experimental food patches placed throughout the home ranges of the two groups. We expected the monkeys to harvest the most from patches in tall forest habitats and the least from patches in short forest. Further, because the monkeys move through their habitats in groups, we expected to see group cohesion effects illustrated by daily spatial variation in the monkeys' use of widespread foraging grids. In the forest height experiments, the two groups differed in their foraging responses, with 8% greater foraging overall for one group. However, forest height did not significantly impact foraging in either group, meaning that, given feeding opportunities, samango monkeys are able to utilize secondary growth forest. For one group, missed opportunity costs of staying with the group appeared through the statistical interaction of day with foraging location (the monkeys did not always spread out to take advantage of all available food patches). In several subsequent experiments in widespread grids, significant daily spatial variation in foraging occurred, pointing to spatial cohesion during group movement as likely being an important predictor of habitat use. For an individual social forager, staying with the group may be more important than habitat type in driving habitat selection. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of Fat and Protein Levels on Foraging Preferences of Tannin in Scatter-Hoarding Rodents

PubMed Central

Wang, Bo; Chen, Jin

2012-01-01

Both as consumers and dispersers of seeds, scatter-hoarding rodents often play an important role in the reproductive ecology of many plant species. However, the seeds of many plant species contain tannins, which are a diverse group of water-soluble phenolic compounds that have a high affinity for proteins. The amount of tannins in seeds is expected to affect rodent foraging preferences because of their major impact on rodent physiology and survival. However, variable results have been obtained in studies that evaluated the effects of tannin on rodent foraging behavior. Hence, in this study, we aimed to explain these inconsistent results and proposed that a combination of seed traits might be important in rodent foraging behavior, because it is difficult to distinguish between the effects of individual traits on rodent foraging behavior and the interactions among them. By using a novel artificial seed system, we manipulated seed tannin and fat/protein levels to examine directly the univariate effects of each component on the seed preferences of free-ranging forest rats (Apodemus latronum and Apodemus chevrieri) during the behavioral process of scatter hoarding. Our results showed that both tannin and fat/protein had significant effects on rodent foraging behavior. Although only a few interactive effects of tannin and fat/protein were recorded, higher concentrations of both fat and protein could attenuate the exclusion of seeds with higher tannin concentrations by rodents, thus influencing seed fate. Furthermore, aside from the concentrations of tannin, fat, and protein, numerous other traits of plant seeds may also influence rodent foraging behavior. We suggest that by clarifying rodent foraging preferences, a better understanding of the evolution of plant seed traits may be obtained because of their strong potential for selective pressure. PMID:22808217

Behavioural environments and niche construction: the evolution of dim-light foraging in bees.

PubMed

Wcislo, William T; Tierney, Simon M

2009-02-01

Most bees forage for floral resources during the day, but temporal patterns of foraging activity vary extensively, and foraging in dim-light environments has evolved repeatedly. Facultative dim-light foraging behaviour is known in five of nine families of bees, while obligate behaviour is known in four families and evolved independently at least 19 times. The light intensity under which bees forage varies by a factor of 10(8), and therefore the evolution of dim-light foraging represents the invasion of a new, extreme niche. The repeated evolution of dim-light foraging behaviour in bees allows tests of the hypothesis that behaviour acts as an evolutionary pacemaker. With the exception of one species of Apis, facultative dim-light foragers show no external structural traits that are thought to enable visually mediated flight behaviour in low-light environments. By contrast, most obligate dim-light foragers show a suite of convergent optical traits such as enlarged ocelli and compound eyes. In one intensively studied species (Megalopta genalis) these optical changes are associated with neurobiological changes to enhance photon capture. The available ecological evidence suggests that an escape from competition for pollen and nectar resources and avoidance of natural enemies are driving factors in the evolution of obligate dim-light foraging.

Resource base influences genome-wide DNA methylation levels in wild baboons (Papio cynocephalus)

PubMed Central

Lea, Amanda J.; Altmann, Jeanne; Alberts, Susan C.; Tung, Jenny

2015-01-01

Variation in resource availability commonly exerts strong effects on fitness-related traits in wild animals. However, we know little about the molecular mechanisms that mediate these effects, or about their persistence over time. To address these questions, we profiled genome-wide whole blood DNA methylation levels in two sets of wild baboons: (i) ‘wild-feeding’ baboons that foraged naturally in a savanna environment and (ii) ‘Lodge’ baboons that had ready access to spatially concentrated human food scraps, resulting in high feeding efficiency and low daily travel distances. We identified 1,014 sites (0.20% of sites tested) that were differentially methylated between wild-feeding and Lodge baboons, providing the first evidence that resource availability shapes the epigenome in a wild mammal. Differentially methylated sites tended to occur in contiguous stretches (i.e., in differentially methylated regions or DMRs), in promoters and enhancers, and near metabolism-related genes, supporting their functional importance in gene regulation. In agreement, reporter assay experiments confirmed that methylation at the largest identified DMR, located in the promoter of a key glycolysis-related gene, was sufficient to causally drive changes in gene expression. Intriguingly, all dispersing males carried a consistent epigenetic signature of their membership in a wild-feeding group, regardless of whether males dispersed into or out of this group as adults. Together, our findings support a role for DNA methylation in mediating ecological effects on phenotypic traits in the wild, and emphasize the dynamic environmental sensitivity of DNA methylation levels across the life course. PMID:26508127

Salinity-mediated cyanogenesis in white clover (Trifolium repens) affects trophic interactions

PubMed Central

Ballhorn, Daniel J.; Elias, Jacob D.

2014-01-01

Background and Aims Increasing soil salinity poses a major plant stress in agro-ecosystems worldwide. Surprisingly little is known about the quantitative effect of elevated salinity on secondary metabolism in many agricultural crops. Such salt-mediated changes in defence-associated compounds may significantly alter the quality of food and forage plants as well as their resistance against pests. In the present study, the effects of soil salinity on cyanogenesis in white clover (Trifolium repens), a forage crop of international importance, are analysed. Methods Experimental clonal plants were exposed to five levels of soil salinity, and cyanogenic potential (HCNp, total amount of accumulated cyanide in a given plant tissue), β-glucosidase activity, soluble protein concentration and biomass production were quantified. The attractiveness of plant material grown under the different salt treatments was tested using cafeteria-style feeding trials with a generalist (grey garden slug, Deroceras reticulatum) and a specialist (clover leaf weevil, Hypera punctata) herbivore. Key Results Salt treatment resulted in an upregulation of HCNp, whereas β-glucosidase activity and soluble protein concentration showed no significant variation among treatments. Leaf area consumption of both herbivore species was negatively correlated with HCNp, indicating bottom-up effects of salinity-mediated changes in HCNp on plant consumers. Conclusions The results suggest that soil salinity leads to an upregulation of cyanogenesis in white clover, which results in enhanced resistance against two different natural herbivores. The potential implications for such salinity-mediated changes in plant defence for livestock grazing remain to be tested. PMID:25006176

Influence of Landmarks on Spatial Memory in Short-nosed Fruit Bat, Cynopterus sphinx.

PubMed

Zeng, Yu; Zhang, Xin-Wen; Zhu, Guang-Jian; Gong, Yan-Yan; Yang, Jian; Zhang, Li-Biao

2010-04-01

In order to study the relationship between landmarks and spatial memory in short-nosed fruit bat, Cynopterus sphinx (Megachiroptera, Pteropodidae), we simulated a foraging environment in the laboratory. Different landmarks were placed to gauge the spatial memory of C. sphinx. We changed the number of landmarks every day with 0 landmarks again on the fifth day (from 0, 2, 4, 8 to 0). Individuals from the control group were exposed to the identical artificial foraging environment, but without landmarks. The results indicated that there was significant correlation between the time of the first foraging and the experimental days in both groups (Pearson Correlation: experimental group: r=-0.593, P<0.01; control group: r=-0.581, P<0.01). There was no significant correlation between the success rates of foraging and the experimental days in experimental groups (Pearson Correlation: r=0.177, P>0.05), but there was significant correlation between the success rates of foraging and the experimental days in the control groups (Pearson Correlation: r=0.445, P<0.05). There was no significant difference for the first foraging time between experimental and control groups (GLM: F(0.05,1 )=4.703, P>0.05); also, there was no significant difference in success rates of foraging between these two groups (GLM: F(0.05,1 )=0.849, P>0.05). The results of our experiment suggest that spatial memory in C. sphinx was formed gradually and that the placed landmarks appeared to have no discernable effects on the memory of the foraging space.

Social cohesion among kin, gene flow without dispersal and the evolution of population genetic structure in the killer whale (Orcinus orca).

PubMed

Pilot, M; Dahlheim, M E; Hoelzel, A R

2010-01-01

In social species, breeding system and gregarious behavior are key factors influencing the evolution of large-scale population genetic structure. The killer whale is a highly social apex predator showing genetic differentiation in sympatry between populations of foraging specialists (ecotypes), and low levels of genetic diversity overall. Our comparative assessments of kinship, parentage and dispersal reveal high levels of kinship within local populations and ongoing male-mediated gene flow among them, including among ecotypes that are maximally divergent within the mtDNA phylogeny. Dispersal from natal populations was rare, implying that gene flow occurs without dispersal, as a result of reproduction during temporary interactions. Discordance between nuclear and mitochondrial phylogenies was consistent with earlier studies suggesting a stochastic basis for the magnitude of mtDNA differentiation between matrilines. Taken together our results show how the killer whale breeding system, coupled with social, dispersal and foraging behaviour, contributes to the evolution of population genetic structure.

Environmental enrichment of brown capuchins (Cebus apella): Behavioral and plasma and fecal cortisol measures of effectiveness

USGS Publications Warehouse

Boinski, S.; Swing, S.P.; Gross, T.S.; Davis, J.K.

1999-01-01

No consensus exists about the quantity and variety of environmental enrichment needed to achieve an acceptable level of psychological well-being among singly housed primates. Behavioral and plasma and fecal cortisol measures were used to evaluate the effectiveness of four levels of toy and foraging enrichment provided to eight wild-caught, singly housed adult male brown capuchins (Cebus apella). The 16-week-long study comprised six conditions and began with a 4-week-long preexperimental and ended with a 4-week-long postexperimental period during which the subjects were maintained at baseline enrichment levels. During the intervening 8 weeks, the subjects were randomly assigned to a sequence of four 2-week-long experimental conditions: control (baseline conditions), toy (the addition of two plastic toys to each cage), box (access to a foraging box with food treats hidden within crushed alfalfa), and box and toy (the addition of two plastic toys and access to a foraging box). Behavioral responses to changes in enrichment were rapid and extensive. Within-subject repeated-measure ANOVAs with planned post hoc contrasts identified highly significant reductions in abnormal and undesirable behaviors (and increases in normal behaviors) as the level of enrichment increased from control to toy to box to box and toy. No significant behavioral differences were found between the control and pre- and postexperimental conditions. Plasma and fecal cortisol measures revealed a different response to changing enrichment levels. Repeated-measure ANOVA models found significant changes in both these measures across the six conditions. The planned post hoc analyses, however, while finding dramatic increases in cortisol titers in both the pre- and postexperimental conditions relative to the control condition, did not distinguish cortisol responses among the four enrichment levels. Linear regressions among weekly group means in behavioral and cortisol measures (n = 16) found that plasma cortisol was significantly predicted by the proportions of both normal and abnormal behaviors; as the proportion of normal behaviors increased, the plasma cortisol measures decreased. Plasma cortisol weekly group means were also significantly and positively predicted by fecal cortisol weekly group means, but no behavioral measure significantly predicted fecal cortisol weekly group means. In sum, these findings argue strongly that access to a variety of toy and foraging enrichment positively affects behavioral and physiological responses to stress and enhances psychological well-being in singly housed brown capuchins.

Environmental enrichment of brown capuchins (Cebus apella): behavioral and plasma and fecal cortisol measures of effectiveness.

PubMed

Boinski, S; Swing, S P; Gross, T S; Davis, J K

1999-01-01

No consensus exists about the quantity and variety of environmental enrichment needed to achieve an acceptable level of psychological well-being among singly housed primates. Behavioral and plasma and fecal cortisol measures were used to evaluate the effectiveness of four levels of toy and foraging enrichment provided to eight wild-caught, singly housed adult male brown capuchins (Cebus apella). The 16-week-long study comprised six conditions and began with a 4-week-long preexperimental and ended with a 4-week-long postexperimental period during which the subjects were maintained at baseline enrichment levels. During the intervening 8 weeks, the subjects were randomly assigned to a sequence of four 2-week-long experimental conditions: control (baseline conditions), toy (the addition of two plastic toys to each cage), box (access to a foraging box with food treats hidden within crushed alfalfa), and box & toy (the addition of two plastic toys and access to a foraging box). Behavioral responses to changes in enrichment were rapid and extensive. Within-subject repeated-measure ANOVAs with planned post hoc contrasts identified highly significant reductions in abnormal and undesirable behaviors (and increases in normal behaviors) as the level of enrichment increased from control to toy to box to box & toy. No significant behavioral differences were found between the control and pre- and postexperimental conditions. Plasma and fecal cortisol measures revealed a different response to changing enrichment levels. Repeated-measure ANOVA models found significant changes in both these measures across the six conditions. The planned post hoc analyses, however, while finding dramatic increases in cortisol titers in both the pre- and postexperimental conditions relative to the control condition, did not distinguish cortisol responses among the four enrichment levels. Linear regressions among weekly group means in behavioral and cortisol measures (n=16) found that plasma cortisol was significantly predicted by the proportions of both normal and abnormal behaviors; as the proportion of normal behaviors increased, the plasma cortisol measures decreased. Plasma cortisol weekly group means were also significantly and positively predicted by fecal cortisol weekly group means, but no behavioral measure significantly predicted fecal cortisol weekly group means. In sum, these findings argue strongly that access to a variety of toy and foraging enrichment positively affects behavioral and physiological responses to stress and enhances psychological well-being in singly housed brown capuchins.

Effects of currents and tides on fine-scale use of marine bird habitats in a Southeast Alaska hotspot

USGS Publications Warehouse

Drew, Gary S.; Piatt, John F.; Hill, David J.

2013-01-01

Areas with high species richness have become focal points in the establishment of marine protected areas, but an understanding of the factors that support this diversity is still incomplete. In coastal areas, tidal currents—modulated by bathymetry and manifested in variable speeds—are a dominant physical feature of the environment. However, difficulties resolving tidally affected currents and depths at fine spatial-temporal scales have limited our ability to understand their influence the distribution of marine birds. We used a hydrographic model of the water mass in Glacier Bay, Alaska to link depths and current velocities with the locations of 15 common marine bird species observed during fine-scale boat-based surveys of the bay conducted during June of four consecutive years (2000-2003). Marine birds that forage on the bottom tended to occupy shallow habitats with slow-moving currents; mid-water foragers used habitats with intermediate depths and current speeds; and surface-foraging species tended to use habitats with fast-moving, deep waters. Within foraging groups there was variability among species in their use of habitats. While species obligated to foraging near bottom were constrained to use similar types of habitat, species in the mid-water foraging group were associated with a wider range of marine habitat characteristics. Species also showed varying levels of site use depending on tide stage. The dramatic variability in bottom topography—especially the presence of numerous sills, islands, headlands and channels—and large tidal ranges in Glacier Bay create a wide range of current-affected fine-scale foraging habitats that may contribute to the high diversity of marine bird species found there.

Laser-induced breakdown spectroscopy used to detect endophyte-mediated accumulation of metals by tall fescue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madhavi Z.; Stewart, Arthur J.; Gwinn, Kimberley D.

Laser-induced breakdown spectroscopy (LIBS) was used to determine the impact of endophyte (Neotyphodium sp.) infection on elemental composition of tall fescue (Festuca arundinacea). Leaf material from endophyte-infected (E+) and endophyte-free (E-) tall fescue populations in established plots was examined. Leaf-tissue digestates were also tested for metals, by inductively coupled plasma (ICP) mass spectrometry (MS). Seven of eleven metals (Ca, Mg, Fe, Mn, Cu, Ni, and Zn) were measured by both techniques at concentrations great enough for a reliable comparison. Mg, Zn, and Cd, a toxic metal that can be present in forage, were readily detected by LIBS, even though Cdmore » concentrations in the plants were below levels typically achieved using ICP MS detection. Implications of these results for research on forage analysis and phytoremediation are discussed.« less

The effects of facilitation and competition on group foraging in patches

PubMed Central

Laguë, Marysa; Tania, Nessy; Heath, Joel; Edelstein-Keshet, Leah

2012-01-01

Significant progress has been made towards understanding the social behaviour of animal groups, but the patch model, a foundation of foraging theory, has received little attention in a social context. The effect of competition on the optimal time to leave a foraging patch was considered as early as the original formulation of the marginal value theorem, but surprisingly, the role of facilitation (where foraging in groups decreases the time to find food in patches), has not been incorporated. Here we adapt the classic patch model to consider how the trade-off between facilitation and competition influence optimal group size. Using simple assumptions about the effect of group size on the food-finding time and the sharing of resources, we find conditions for existence of optima in patch residence time and in group size. When patches are close together (low travel times), larger group sizes are optimal. Groups are predicted to exploit patches differently than individual foragers and the degree of patch depletion at departure depends on the details of the trade-off between competition and facilitation. A variety of currencies and group-size effects are also considered and compared. Using our simple formulation, we also study the effects of social foraging on patch exploitation which to date have received little empirical study. PMID:22743132

The effects of facilitation and competition on group foraging in patches.

PubMed

Laguë, Marysa; Tania, Nessy; Heath, Joel; Edelstein-Keshet, Leah

2012-10-07

Significant progress has been made towards understanding the social behaviour of animal groups, but the patch model, a foundation of foraging theory, has received little attention in a social context. The effect of competition on the optimal time to leave a foraging patch was considered as early as the original formulation of the marginal value theorem, but surprisingly, the role of facilitation (where foraging in groups decreases the time to find food in patches), has not been incorporated. Here we adapt the classic patch model to consider how the trade-off between facilitation and competition influences optimal group size. Using simple assumptions about the effect of group size on the food-finding time and the sharing of resources, we find conditions for existence of optima in patch residence time and in group size. When patches are close together (low travel times), larger group sizes are optimal. Groups are predicted to exploit patches differently than individual foragers and the degree of patch depletion at departure depends on the details of the trade-off between competition and facilitation. A variety of currencies and group-size effects are also considered and compared. Using our simple formulation, we also study the effects of social foraging on patch exploitation which to date have received little empirical study. Copyright © 2012 Elsevier Ltd. All rights reserved.

Scavengers on the move: behavioural changes in foraging search patterns during the annual cycle.

PubMed

López-López, Pascual; Benavent-Corai, José; García-Ripollés, Clara; Urios, Vicente

2013-01-01

Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal response at the individual level has received little attention. We used GPS satellite-telemetry data of Egyptian vultures Neophron percnopterus to examine movement patterns at the individual level during consecutive years, with particular interest in the variations in foraging search patterns during the different periods of the annual cycle (i.e. breeding vs. non-breeding). Our results show that vultures followed a brownian search strategy in their wintering sojourn in Africa, whereas they exhibited a more complex foraging search pattern at breeding grounds in Europe, including Lévy motion. Interestingly, our results showed that individuals shifted between search strategies within the same period of the annual cycle in successive years. Results could be primarily explained by the different environmental conditions in which foraging activities occur. However, the high degree of behavioural flexibility exhibited during the breeding period in contrast to the non-breeding period is challenging, suggesting that not only environmental conditions explain individuals' behaviour but also individuals' cognitive abilities (e.g., memory effects) could play an important role. Our results support the growing awareness about the role of behavioural flexibility at the individual level, adding new empirical evidence about how animals in general, and particularly scavengers, solve the problem of efficiently finding food resources.

Determination of Phytoestrogen Content in Fresh-Cut Legume Forage

PubMed Central

Hloucalová, Pavlína; Skládanka, Jiří; Horký, Pavel; Klejdus, Bořivoj; Pelikán, Jan; Knotová, Daniela

2016-01-01

Simple Summary Phytoestrogens comprise a group of substances negatively influencing the development and function of animal reproductive organs. Their appearance in forage crops can reduce feeding values, cause dietary disorders, and lead to animal health damage. This study evaluated the occurrence of individual phytoestrogens in various species of annual and perennial legumes and their levels in dry forage. It appeared that feeding large amounts of red clover presents a potential risk, but red clover can be replaced with the annual Persian clover, in which markedly lower phytoestrogen levels were detected. Abstract The aim of the study was to determine phytoestrogen content in fresh-cut legume forage. This issue has been much discussed in recent years in connection with the health and safety of feedstuffs and thus livestock health. The experiments were carried out on two experimental plots at Troubsko and Vatín, Czech Republic during June and July in 2015. Samples were collected of the four forage legume species perennial red clover (variety “Amos”), alfalfa (variety “Holyně”), and annuals Persian clover and Alexandrian clover. Forage was sampled twice at regular three to four day intervals leading up to harvest and a third time on the day of harvest. Fresh and wilted material was analyzed using liquid chromatography–mass spectrometry (LC-MS). Higher levels (p < 0.05) of isoflavones biochanin A (3.697 mg·g−1 of dry weight) and formononetin (4.315 mg·g−1 of dry weight) were found in red clover than in other species. The highest isoflavone content was detected in red clover, reaching 1.001% of dry matter (p < 0.05), representing a risk for occurrence of reproduction problems and inhibited secretion of animal estrogen. The phytoestrogen content was particularly increased in wilted forage. Significant isoflavone reduction was observed over three to four day intervals leading up to harvest. PMID:27429009

Body size mediated coexistence in swans.

PubMed

Engelhardt, Katharina A M; Ritchie, Mark E; Powell, James A

2014-01-01

Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource.

Body Size Mediated Coexistence in Swans

PubMed Central

Engelhardt, Katharina A. M.; Ritchie, Mark E.; Powell, James A.

2014-01-01

Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource. PMID:24672347

Composite collective decision-making

PubMed Central

Czaczkes, Tomer J.; Czaczkes, Benjamin; Iglhaut, Carolin; Heinze, Jürgen

2015-01-01

Individual animals are adept at making decisions and have cognitive abilities, such as memory, which allow them to hone their decisions. Social animals can also share information. This allows social animals to make adaptive group-level decisions. Both individual and collective decision-making systems also have drawbacks and limitations, and while both are well studied, the interaction between them is still poorly understood. Here, we study how individual and collective decision-making interact during ant foraging. We first gathered empirical data on memory-based foraging persistence in the ant Lasius niger. We used these data to create an agent-based model where ants may use social information (trail pheromones), private information (memories) or both to make foraging decisions. The combined use of social and private information by individuals results in greater efficiency at the group level than when either information source was used alone. The modelled ants couple consensus decision-making, allowing them to quickly exploit high-quality food sources, and combined decision-making, allowing different individuals to specialize in exploiting different resource patches. Such a composite collective decision-making system reaps the benefits of both its constituent parts. Exploiting such insights into composite collective decision-making may lead to improved decision-making algorithms. PMID:26019155

Two Loci on Chromosome 5 Are Associated with Serum IgE Levels in Labrador Retrievers

PubMed Central

Owczarek-Lipska, Marta; Lauber, Béatrice; Molitor, Vivianne; Meury, Sabrina; Kierczak, Marcin; Tengvall, Katarina; Webster, Matthew T.; Jagannathan, Vidhya; Schlotter, Yvette; Willemse, Ton; Hendricks, Anke; Bergvall, Kerstin; Hedhammar, Åke; Andersson, Göran; Lindblad-Toh, Kerstin; Favrot, Claude; Roosje, Petra; Marti, Eliane; Leeb, Tosso

2012-01-01

Crosslinking of immunoglobulin E antibodies (IgE) bound at the surface of mast cells and subsequent mediator release is considered the most important trigger for allergic reactions. Therefore, the genetic control of IgE levels is studied in the context of allergic diseases, such as asthma, atopic rhinitis, or atopic dermatitis (AD). We performed genome-wide association studies in 161 Labrador Retrievers with regard to total and allergen-specific immunoglobulin E (IgE) levels. We identified a genome-wide significant association on CFA 5 with the antigen-specific IgE responsiveness to Acarus siro. We detected a second genome-wide significant association with respect to the antigen-specific IgE responsiveness to Tyrophagus putrescentiae at a different locus on chromosome 5. A. siro and T. putrescentiae both belong to the family Acaridae and represent so-called storage or forage mites. These forage mites are discussed as major allergen sources in canine AD. No obvious candidate gene for the regulation of IgE levels is located under the two association signals. Therefore our studies offer a chance of identifying a novel mechanism controlling the host's IgE response. PMID:22720065

Physiology of reproductive worker honey bees (Apis mellifera): insights for the development of the worker caste.

PubMed

Peso, Marianne; Even, Naïla; Søvik, Eirik; Naeger, Nicholas L; Robinson, Gene E; Barron, Andrew B

2016-02-01

Reproductive and behavioural specialisations characterise advanced social insect societies. Typically, the honey bee (Apis mellifera) shows a pronounced reproductive division of labour between worker and queen castes, and a clear division of colony roles among workers. In a queenless condition, however, both of these aspects of social organisation break down. Queenless workers reproduce, forage and maintain their colony operating in a manner similar to communal bees, rather than as an advanced eusocial group. This plasticity in social organisation provides a natural experiment for exploring physiological mechanisms of division of labour. We measured brain biogenic amine (BA) levels and abdominal fat body vitellogenin gene expression levels of workers in queenright and queenless colonies. Age, ovary activation and social environment influenced brain BA levels in honey bees. BA levels were most influenced by ovary activation state in queenless bees. Vitellogenin expression levels were higher in queenless workers than queenright workers, but in both colony environments vitellogenin expression was lower in foragers than non-foragers. We propose this plasticity in the interacting signalling systems that influence both reproductive and behavioural development allows queenless workers to deviate significantly from the typical worker bee reaction norm and develop as reproductively active behavioural generalists.

Robustness of self-organised systems to changes in behaviour: an example from real and simulated self-organised snail aggregations.

PubMed

Stafford, Richard; Williams, Gray A; Davies, Mark S

2011-01-01

Group or population level self-organised systems comprise many individuals displaying group-level emergent properties. Current theory indicates that individual-level behaviours have an effect on the final group-level behaviour; that is, self-organised systems are sensitive to small changes in individual behaviour. Here we examine a self-organised behaviour in relation to environmentally-driven individual-level changes in behaviour, using both natural systems and computer simulations. We demonstrate that aggregations of intertidal snails slightly decrease in size when, owing to hotter and more desiccating conditions, individuals forage for shorter periods--a seemingly non-adaptive behaviour for the snails since aggregation reduces desiccation stress. This decrease, however, only occurs in simple experimental systems (and simulations of these systems). When studied in their natural and more complex environment, and simulations of such an environment, using the same reduced foraging time, no difference in aggregation behaviour was found between hot and cool days. These results give an indication of how robust self-organised systems are to changes in individual-level behaviour. The complexity of the natural environment and the interactions of individuals with this environment, therefore, can result in self-organised systems being more resilient to individual-level changes than previously assumed.

Bigger is better: honeybee colonies as distributed information-gathering systems.

PubMed

Donaldson-Matasci, Matina C; DeGrandi-Hoffman, Gloria; Dornhaus, Anna

2013-03-01

In collectively foraging groups, communication about food resources can play an important role in the organization of the group's activity. For example, the honeybee dance communication system allows colonies to selectively allocate foragers among different floral resources according to their quality. Because larger groups can potentially collect more information than smaller groups, they might benefit more from communication because it allows them to integrate and use that information to coordinate forager activity. Larger groups might also benefit more from communication because it allows them to dominate high-value resources by recruiting large numbers of foragers. By manipulating both colony size and the ability to communicate location information in the dance, we show that larger colonies of honeybees benefit more from communication than do smaller colonies. In fact, colony size and dance communication worked together to improve foraging performance; the estimated net gain per foraging trip was highest in larger colonies with unimpaired communication. These colonies also had the earliest peaks in foraging activity, but not the highest ones. This suggests they may find and recruit to resources more quickly, but not more heavily. The benefits of communication we observed in larger colonies are thus likely a result of more effective informationgathering due to massive parallel search rather than increased competitive ability due to heavy recruitment.

The effect of olfactory exposure to non-insecticidal agrochemicals on bumblebee foraging behavior.

PubMed

Sprayberry, Jordanna D H; Ritter, Kaitlin A; Riffell, Jeffrey A

2013-01-01

Declines in bumblebee populations have led to investigations into potential causes - including agrochemical effects on bumblebee physiology. The indirect effects of agrochemicals (i.e. behavior modulation) have been postulated, but rarely directly tested. Olfactory information is critical in mediating bumblebee-floral interactions. As agrochemicals emit volatiles, they may indirectly modify foraging behavior. We tested the effects of olfactory contamination of floral odor by agrochemical scent on foraging activity of Bombus impatiens using two behavioral paradigms: localization of food within a maze and forced-choice preference. The presence of a fungicide decreased bumblebees' ability to locate food within a maze. Additionally, bumblebees preferred to forage in non-contaminated feeding chambers when offered a choice between control and either fertilizer- or fungicide-scented chambers.

Shedding light on light: benefits of anthropogenic illumination to a nocturnally foraging shorebird.

PubMed

Dwyer, Ross G; Bearhop, Stuart; Campbell, Hamish A; Bryant, David M

2013-03-01

Intertidal habitats provide important feeding areas for migratory shorebirds. Anthropogenic developments along coasts can increase ambient light levels at night across adjacent inter-tidal zones. Here, we report the effects of elevated nocturnal light levels upon the foraging strategy of a migratory shorebird (common redshank Tringa totanus) overwintering on an industrialised estuary in Northern Europe. To monitor behaviour across the full intertidal area, individuals were located by day and night using VHF transmitters, and foraging behaviour was inferred from inbuilt posture sensors. Natural light was scored using moon-phase and cloud cover information and nocturnal artificial light levels were obtained using geo-referenced DMSP/OLS night-time satellite imagery at a 1-km resolution. Under high illumination levels, the commonest and apparently preferred foraging behaviour was sight-based. Conversely, birds feeding in areas with low levels of artificial light had an elevated foraging time and fed by touch, but switched to visual rather than tactile foraging behaviour on bright moonlit nights in the absence of cloud cover. Individuals occupying areas which were illuminated continuously by lighting from a large petrochemical complex invariably exhibited a visually based foraging behaviour independently of lunar phase and cloud cover. We show that ambient light levels affect the timing and distribution of foraging opportunities for redshank. We argue that light emitted from an industrial complex improved nocturnal visibility. This allowed sight-based foraging in place of tactile foraging, implying both a preference for sight-feeding and enhanced night-time foraging opportunities under these conditions. The study highlights the value of integrating remotely sensed data and telemetry techniques to assess the effect of anthropogenic change upon nocturnal behaviour and habitat use. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Flight is the key to postprandial blood glucose balance in the fruit bats Eonycteris spelaea and Cynopterus sphinx.

PubMed

Peng, Xingwen; He, Xiangyang; Liu, Qi; Sun, Yunxiao; Liu, Hui; Zhang, Qin; Liang, Jie; Peng, Zhen; Liu, Zhixiao; Zhang, Libiao

2017-11-01

Excessive sugar consumption could lead to high blood glucose levels that are harmful to mammalian health and life. Despite consuming large amounts of sugar-rich food, fruit bats have a longer lifespan, raising the question of how these bats overcome potential hyperglycemia. We investigated the change of blood glucose level in nectar-feeding bats ( Eonycteris spelaea ) and fruit-eating bats ( Cynopterus sphinx ) via adjusting their sugar intake and time of flight. We found that the maximum blood glucose level of C. sphinx was higher than 24 mmol/L that is considered to be pathological in other mammals. After C. sphinx bats spent approximately 75% of their time to fly, their blood glucose levels dropped markedly, and the blood glucose of E. spelaea fell to the fast levels after they spent 70% time of fly. Thus, the level of blood glucose elevated with the quantity of sugar intake but declined with the time of flight. Our results indicate that high-intensive flight is a key regulator for blood glucose homeostasis during foraging. High-intensive flight may confer benefits to the fruit bats in foraging success and behavioral interactions and increases the efficiency of pollen and seed disposal mediated by bats.

Foraging for brain stimulation: toward a neurobiology of computation.

PubMed

Gallistel, C R

1994-01-01

The self-stimulating rat performs foraging tasks mediated by simple computations that use interreward intervals and subjective reward magnitudes to determine stay durations. This is a simplified preparation in which to study the neurobiology of the elementary computational operations that make cognition possible, because the neural signal specifying the value of a computationally relevant variable is produced by direct electrical stimulation of a neural pathway. Newly developed measurement methods yield functions relating the subjective reward magnitude to the parameters of the neural signal. These measurements also show that the decision process that governs foraging behavior divides the subjective reward magnitude by the most recent interreward interval to determine the preferability of an option (a foraging patch). The decision process sets the parameters that determine stay durations (durations of visits to foraging patches) so that the ratios of the stay durations match the ratios of the preferabilities.

Systematic review of the influence of foraging habitat on red-cockaded woodpecker reproductive success.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garabedian, James E.

Relationships between foraging habitat and reproductive success provide compelling evidence of the contribution of specific vegetative features to foraging habitat quality, a potentially limiting factor for many animal populations. For example, foraging habitat quality likely will gain importance in the recovery of the threatened red-cockaded woodpecker Picoides borealis (RCW) in the USA as immediate nesting constraints are mitigated. Several researchers have characterized resource selection by foraging RCWs, but emerging research linking reproductive success (e.g. clutch size, nestling and fledgling production, and group size) and foraging habitat features has yet to be synthesized. Therefore, we reviewed peer-refereed scientific literature and technicalmore » resources (e.g. books, symposia proceedings, and technical reports) that examined RCW foraging ecology, foraging habitat, or demography to evaluate evidence for effects of the key foraging habitat features described in the species’ recovery plan on group reproductive success. Fitness-based habitat models suggest foraging habitat with low to intermediate pine Pinus spp. densities, presence of large and old pines, minimal midstory development, and herbaceous groundcover support more productive RCW groups. However, the relationships between some foraging habitat features and RCW reproductive success are not well supported by empirical data. In addition, few regression models account for > 30% of variation in reproductive success, and unstandardized multiple and simple linear regression coefficient estimates typically range from -0.100 to 0.100, suggesting ancillary variables and perhaps indirect mechanisms influence reproductive success. These findings suggest additional research is needed to address uncertainty in relationships between foraging habitat features and RCW reproductive success and in the mechanisms underlying those relationships.« less

40 CFR 180.515 - Carfentrazone-ethyl; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., green 0.10 Corn, field, forage 0.20 Corn, sweet, forage 0.20 Corn, sweet, kernel plus cob with husk....8 Grain, cereal, forage, fodder and straw group 16, except corn and sorghum; forage 1.0 Grain...

40 CFR 180.515 - Carfentrazone-ethyl; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., green 0.10 Corn, field, forage 0.20 Corn, sweet, forage 0.20 Corn, sweet, kernel plus cob with husk....8 Grain, cereal, forage, fodder and straw group 16, except corn and sorghum; forage 1.0 Grain...

78 FR 53139 - Pesticide Product Registration; Receipt of Application for New Uses

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-28

...: Flonicamid. Product Name: Technical Flonicamid Insecticide. Proposed Use(s): Alfalfa, forage; alfalfa, hay; alfalfa, seed; clover, forage; clover, hay; fruit, pome (crop group 11-10); fruit, stone (crop group 12-12...: Flonicamid. Product Name: Technical Flonicamid Insecticide. Proposed Use(s): Alfalfa, forage; alfalfa, hay...

Four types of interference competition and their impacts on the ecology and evolution of size-structured populations and communities.

PubMed

Zhang, Lai; Andersen, Ken H; Dieckmann, Ulf; Brännström, Åke

2015-09-07

We investigate how four types of interference competition - which alternatively affect foraging, metabolism, survival, and reproduction - impact the ecology and evolution of size-structured populations. Even though all four types of interference competition reduce population biomass, interference competition at intermediate intensity sometimes significantly increases the abundance of adult individuals and the population׳s reproduction rate. We find that foraging and metabolic interference evolutionarily favor smaller maturation size when interference is weak and larger maturation size when interference is strong. The evolutionary response to survival interference and reproductive interference is always larger maturation size. We also investigate how the four types of interference competition impact the evolutionary dynamics and resultant diversity and trophic structure of size-structured communities. Like other types of trait-mediated competition, all four types of interference competition can induce disruptive selection and thus promote initial diversification. Even though foraging interference and reproductive interference are more potent in promoting initial diversification, they catalyze the formation of diverse communities with complex trophic structure only at high levels of interference intensity. By contrast, survival interference does so already at intermediate levels, while reproductive interference can only support relatively smaller communities with simpler trophic structure. Taken together, our results show how the type and intensity of interference competition jointly affect coexistence patterns in structured population models. Copyright © 2015 Elsevier Ltd. All rights reserved.

Colony-level behavioural variation correlates with differences in expression of the foraging gene in red imported fire ants.

PubMed

Bockoven, Alison A; Coates, Craig J; Eubanks, Micky D

2017-11-01

Among social insects, colony-level variation is likely to be widespread and has significant ecological consequences. Very few studies, however, have documented how genetic factors relate to behaviour at the colony level. Differences in expression of the foraging gene have been associated with differences in foraging and activity of a wide variety of organisms. We quantified expression of the red imported fire ant foraging gene (sifor) in workers from 21 colonies collected across the natural range of Texas fire ant populations, but maintained under standardized, environmentally controlled conditions. Colonies varied significantly in their behaviour. The most active colonies had up to 10 times more active foragers than the least active colony and more than 16 times as many workers outside the nest. Expression differences among colonies correlated with this colony-level behavioural variation. Colonies with higher sifor expression in foragers had, on average, significantly higher foraging activity, exploratory activity and recruitment to nectar than colonies with lower expression. Expression of sifor was also strongly correlated with worker task (foraging vs. working in the interior of the nest). These results provide insight into the genetic and physiological processes underlying collective differences in social behaviour. Quantifying variation in expression of the foraging gene may provide an important tool for understanding and predicting the ecological consequences of colony-level behavioural variation. © 2017 John Wiley & Sons Ltd.

75 FR 17564 - Chlorantraniliprole; Extension of Time-Limited Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-07

... at 0.20 ppm; grass, forage, fodder and hay, crop group 17 at 0.20 ppm; vegetable, leaves of root and... hay (includes cowpea, forage and hay; field pea, vines and hay); grass, forage, fodder and hay, crop...-limited tolerances for cowpea, forage and hay; field pea, vines and hay; grass, forage, fodder and hay...

Non-random nectar unloading interactions between foragers and their receivers in the honeybee hive

NASA Astrophysics Data System (ADS)

Goyret, Joaquín; Farina, Walter M.

2005-09-01

Nectar acquisition in the honeybee Apis mellifera is a partitioned task in which foragers gather nectar and bring it to the hive, where nest mates unload via trophallaxis (i.e. mouth-to-mouth transfer) the collected food for further storage. Because forager mates exploit different feeding places simultaneously, this study addresses the question of whether nectar unloading interactions between foragers and hive-bees are established randomly, as it is commonly assumed. Two groups of foragers were trained to exploit a different scented food source for 5 days. We recorded their trophallaxes with hive-mates, marking the latter ones according to the forager group they were unloading. We found non-random probabilities for the occurrence of trophallaxes between experimental foragers and hive-bees, instead, we found that trophallactic interactions were more likely to involve groups of individuals which had formerly interacted orally. We propose that olfactory cues present in the transferred nectar promoted the observed bias, and we discuss this bias in the context of the organization of nectar acquisition: a partitioned task carried out in a decentralized insect society.

Seasonal Food Scarcity Prompts Long-Distance Foraging by a Wild Social Bee.

PubMed

Pope, Nathaniel S; Jha, Shalene

2018-01-01

Foraging is an essential process for mobile animals, and its optimization serves as a foundational theory in ecology and evolution; however, drivers of foraging are rarely investigated across landscapes and seasons. Using a common bumblebee species from the western United States (Bombus vosnesenskii), we ask whether seasonal decreases in food resources prompt changes in foraging behavior and space use. We employ a unique integration of population genetic tools and spatially explicit foraging models to estimate foraging distances and rates of patch visitation for wild bumblebee colonies across three study regions and two seasons. By mapping the locations of 669 wild-caught individual foragers, we find substantial variation in colony-level foraging distances, often exhibiting a 60-fold difference within a study region. Our analysis of visitation rates indicates that foragers display a preference for destination patches with high floral cover and forage significantly farther for these patches, but only in the summer, when landscape-level resources are low. Overall, these results indicate that an increasing proportion of long-distance foraging bouts take place in the summer. Because wild bees are pollinators, their foraging dynamics are of urgent concern, given the potential impacts of global change on their movement and services. The behavioral shift toward long-distance foraging with seasonal declines in food resources suggests a novel, phenologically directed approach to landscape-level pollinator conservation and greater consideration of late-season floral resources in pollinator habitat management.

The Effect of Olfactory Exposure to Non-Insecticidal Agrochemicals on Bumblebee Foraging Behavior

PubMed Central

Sprayberry, Jordanna D. H.; Ritter, Kaitlin A.; Riffell, Jeffrey A.

2013-01-01

Declines in bumblebee populations have led to investigations into potential causes – including agrochemical effects on bumblebee physiology. The indirect effects of agrochemicals (i.e. behavior modulation) have been postulated, but rarely directly tested. Olfactory information is critical in mediating bumblebee-floral interactions. As agrochemicals emit volatiles, they may indirectly modify foraging behavior. We tested the effects of olfactory contamination of floral odor by agrochemical scent on foraging activity of Bombus impatiens using two behavioral paradigms: localization of food within a maze and forced-choice preference. The presence of a fungicide decreased bumblebees’ ability to locate food within a maze. Additionally, bumblebees preferred to forage in non-contaminated feeding chambers when offered a choice between control and either fertilizer- or fungicide-scented chambers. PMID:24204608

Breeding short-tailed shearwaters buffer local environmental variability in south-eastern Australia by foraging in Antarctic waters.

PubMed

Berlincourt, Maud; Arnould, John P Y

2015-01-01

Establishing patterns of movements of free-ranging animals in marine ecosystems is crucial for a better understanding of their feeding ecology, life history traits and conservation. As central place foragers, the habitat use of nesting seabirds is heavily influenced by the resources available within their foraging range. We tested the prediction that during years with lower resource availability, short-tailed shearwaters (Puffinus tenuirostris) provisioning chicks should increase their foraging effort, by extending their foraging range and/or duration, both when foraging in neritic (short trips) and distant oceanic waters (long trips). Using both GPS and geolocation data-loggers, at-sea movements and habitat use were investigated over three breeding seasons (2012-14) at two colonies in southeastern Australia. Most individuals performed daily short foraging trips over the study period and inter-annual variations observed in foraging parameters where mainly due to few individuals from Griffith Island, performing 2-day trips in 2014. When performing long foraging trips, this study showed that individuals from both colonies exploited similar zones in the Southern Ocean. The results of this study suggest that individuals could increase their foraging range while exploiting distant feeding zones, which could indicate that short-tailed shearwaters forage in Antarctic waters not only to maintain their body condition but may also do so to buffer against local environmental stochasticity. Lower breeding performances were associated with longer foraging trips to distant oceanic waters in 2013 and 2014 indicating they could mediate reductions in food availability around the breeding colonies by extending their foraging range in the Southern Ocean. This study highlights the importance of foraging flexibility as a fundamental aspect of life history in coastal/pelagic marine central place foragers living in highly variable environments and how these foraging strategies are use to buffer this variability.

Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade

USGS Publications Warehouse

Kauffman, Matthew J.; Brodie, Jedediah F.; Jules, Erik S.

2010-01-01

Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passive (sit-and-wait) predators have much stronger effects than active (coursing) predators. One BMTC that has been proposed for a wide-ranging active predator system involves the reintroduction of wolves (Canis lupus) to Yellowstone National Park, USA, which is thought to be leading to a recovery of trembling aspen (Populus tremuloides) by causing elk (Cervus elaphus) to avoid foraging in risky areas. Although this BMTC has been generally accepted and highly popularized, it has never been adequately tested. We assessed whether wolves influence aspen by obtaining detailed demographic data on aspen stands using tree rings and by monitoring browsing levels in experimental elk exclosures arrayed across a gradient of predation risk for three years. Our study demonstrates that the historical failure of aspen to regenerate varied widely among stands (last recruitment year ranged from 1892 to 1956), and our data do not indicate an abrupt cessation of recruitment. This pattern of recruitment failure appears more consistent with a gradual increase in elk numbers rather than a rapid behavioral shift in elk foraging following wolf extirpation. In addition, our estimates of relative survivorship of young browsable aspen indicate that aspen are not currently recovering in Yellowstone, even in the presence of a large wolf population. Finally, in an experimental test of the BMTC hypothesis we found that the impacts of elk browsing on aspen demography are not diminished in sites where elk are at higher risk of predation by wolves. These findings suggest the need to further evaluate how trophic cascades are mediated by predator–prey life history and ecological context.

Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade.

PubMed

Kauffman, Matthew J; Brodie, Jedediah F; Jules, Erik S

2010-09-01

Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passive (sit-and-wait) predators have much stronger effects than active (coursing) predators. One BMTC that has been proposed for a wide-ranging active predator system involves the reintroduction of wolves (Canis lupus) to Yellowstone National Park, USA, which is thought to be leading to a recovery of trembling aspen (Populus tremuloides) by causing elk (Cervus elaphus) to avoid foraging in risky areas. Although this BMTC has been generally accepted and highly popularized, it has never been adequately tested. We assessed whether wolves influence aspen by obtaining detailed demographic data on aspen Stands using tree rings and by monitoring browsing levels in experimental elk exclosures arrayed across a gradient of predation risk for three years. Our study demonstrates that the historical failure of aspen to regenerate varied widely among stands (last recruitment year ranged from 1892 to 1956), and our data do not indicate an abrupt cessation of recruitment. This pattern of recruitment failure appears more consistent with a gradual increase in elk numbers rather than a rapid behavioral shift in elk foraging following wolf extirpation. In addition, our estimates of relative survivorship of young browsable aspen indicate that aspen are not currently recovering in Yellowstone, even in the presence of a large wolf population. Finally, in an experimental test of the BMTC hypothesis we found that the impacts of elk browsing on aspen demography are not diminished in sites where elk are at higher risk of predation by wolves. These findings suggest the need to further evaluate how trophic cascades are mediated by predator-prey life history and ecological context.

Bigger is better: honeybee colonies as distributed information-gathering systems

PubMed Central

Donaldson-Matasci, Matina C.; DeGrandi-Hoffman, Gloria; Dornhaus, Anna

2015-01-01

In collectively foraging groups, communication about food resources can play an important role in the organization of the group’s activity. For example, the honeybee dance communication system allows colonies to selectively allocate foragers among different floral resources according to their quality. Because larger groups can potentially collect more information than smaller groups, they might benefit more from communication because it allows them to integrate and use that information to coordinate forager activity. Larger groups might also benefit more from communication because it allows them to dominate high-value resources by recruiting large numbers of foragers. By manipulating both colony size and the ability to communicate location information in the dance, we show that larger colonies of honeybees benefit more from communication than do smaller colonies. In fact, colony size and dance communication worked together to improve foraging performance; the estimated net gain per foraging trip was highest in larger colonies with unimpaired communication. These colonies also had the earliest peaks in foraging activity, but not the highest ones. This suggests they may find and recruit to resources more quickly, but not more heavily. The benefits of communication we observed in larger colonies are thus likely a result of more effective informationgathering due to massive parallel search rather than increased competitive ability due to heavy recruitment. PMID:26213412

Role of social interactions in dynamic patterns of resource patches and forager aggregation.

PubMed

Tania, Nessy; Vanderlei, Ben; Heath, Joel P; Edelstein-Keshet, Leah

2012-07-10

The dynamics of resource patches and species that exploit such patches are of interest to ecologists, conservation biologists, modelers, and mathematicians. Here we consider how social interactions can create unique, evolving patterns in space and time. Whereas simple prey taxis (with consumable prey) promotes spatial uniform distributions, here we show that taxis in producer-scrounger groups can lead to pattern formation. We consider two types of foragers: those that search directly ("producers") and those that exploit other foragers to find food ("scroungers" or exploiters). We show that such groups can sustain fluctuating spatiotemporal patterns, akin to "waves of pursuit." Investigating the relative benefits to the individuals, we observed conditions under which either strategy leads to enhanced success, defined as net food consumption. Foragers that search for food directly have an advantage when food patches are localized. Those that seek aggregations of group mates do better when their ability to track group mates exceeds the foragers' food-sensing acuity. When behavioral switching or reproductive success of the strategies is included, the relative abundance of foragers and exploiters is dynamic over time, in contrast with classic models that predict stable frequencies. Our work shows the importance of considering two-way interaction--i.e., how food distribution both influences and is influenced by social foraging and aggregation of predators.

Hunter-gatherer residential mobility and the marginal value of rainforest patches.

PubMed

Venkataraman, Vivek V; Kraft, Thomas S; Dominy, Nathaniel J; Endicott, Kirk M

2017-03-21

The residential mobility patterns of modern hunter-gatherers broadly reflect local resource availability, but the proximate ecological and social forces that determine the timing of camp movements are poorly known. We tested the hypothesis that the timing of such moves maximizes foraging efficiency as hunter-gatherers move across the landscape. The marginal value theorem predicts when a group should depart a camp and its associated foraging area and move to another based on declining marginal return rates. This influential model has yet to be directly applied in a population of hunter-gatherers, primarily because the shape of gain curves (cumulative resource acquisition through time) and travel times between patches have been difficult to estimate in ethnographic settings. We tested the predictions of the marginal value theorem in the context of hunter-gatherer residential mobility using historical foraging data from nomadic, socially egalitarian Batek hunter-gatherers ( n  = 93 d across 11 residential camps) living in the tropical rainforests of Peninsular Malaysia. We characterized the gain functions for all resources acquired by the Batek at daily timescales and examined how patterns of individual foraging related to the emergent property of residential movements. Patterns of camp residence times conformed well with the predictions of the marginal value theorem, indicating that communal perceptions of resource depletion are closely linked to collective movement decisions. Despite (and perhaps because of) a protracted process of deliberation and argument about when to depart camps, Batek residential mobility seems to maximize group-level foraging efficiency.

Hunter-gatherer residential mobility and the marginal value of rainforest patches

PubMed Central

Venkataraman, Vivek V.; Kraft, Thomas S.; Endicott, Kirk M.

2017-01-01

The residential mobility patterns of modern hunter-gatherers broadly reflect local resource availability, but the proximate ecological and social forces that determine the timing of camp movements are poorly known. We tested the hypothesis that the timing of such moves maximizes foraging efficiency as hunter-gatherers move across the landscape. The marginal value theorem predicts when a group should depart a camp and its associated foraging area and move to another based on declining marginal return rates. This influential model has yet to be directly applied in a population of hunter-gatherers, primarily because the shape of gain curves (cumulative resource acquisition through time) and travel times between patches have been difficult to estimate in ethnographic settings. We tested the predictions of the marginal value theorem in the context of hunter-gatherer residential mobility using historical foraging data from nomadic, socially egalitarian Batek hunter-gatherers (n = 93 d across 11 residential camps) living in the tropical rainforests of Peninsular Malaysia. We characterized the gain functions for all resources acquired by the Batek at daily timescales and examined how patterns of individual foraging related to the emergent property of residential movements. Patterns of camp residence times conformed well with the predictions of the marginal value theorem, indicating that communal perceptions of resource depletion are closely linked to collective movement decisions. Despite (and perhaps because of) a protracted process of deliberation and argument about when to depart camps, Batek residential mobility seems to maximize group-level foraging efficiency. PMID:28265058

Facilitation and Dominance in a Schooling Predator: Foraging Behavior of Florida Pompano, Trachinotus carolinus

PubMed Central

2015-01-01

Presumably an individual’s risk of predation is reduced by group membership and this ‘safety in numbers’ concept has been readily applied to investigations of schooling prey; however, foraging in groups may also be beneficial. We tested the hypothesis that, when feeding in groups, foraging of a coastal fish (Florida Pompano, Trachinotus carolinus) on a benthic prey source would be facilitated (i.e. fish feeding in groups will consume more prey items). Although this question has been addressed for other fish species, it has not been previously addressed for Florida Pompano, a fish known to exhibit schooling behavior and that is used for aquaculture, where understanding the feeding ecology is important for healthy and efficient grow-out. In this experiment, juvenile Florida Pompano were offered a fixed number of coquina clams (Donax spp.) for one hour either in a group or as individuals. The following day they were tested in the opposite configuration. Fish in groups achieved greater consumption (average of 26 clams consumed by the entire group) than the individuals comprising the group (average of 14 clams consumed [sum of clams consumed by all individuals of the group]). Fish in groups also had fewer unsuccessful foraging attempts (2.75 compared to 4.75 hr-1) and tended to have a shorter latency until the first feeding activity. Our results suggest fish in groups were more comfortable feeding and more successful in their feeding attempts. Interestingly, the consumption benefit of group foraging was not shared by all – not all fish within a group consumed equal numbers of clams. Taken together, the results support our hypothesis that foraging in a group provides facilitation, but the short-term benefits are not equally shared by all individuals. PMID:26068114

Prey state shapes the effects of temporal variation in predation risk

PubMed Central

Matassa, Catherine M.; Trussell, Geoffrey C.

2014-01-01

The ecological impacts of predation risk are influenced by how prey allocate foraging effort across periods of safety and danger. Foraging decisions depend on current danger, but also on the larger temporal, spatial or energetic context in which prey manage their risks of predation and starvation. Using a rocky intertidal food chain, we examined the responses of starved and fed prey (Nucella lapillus dogwhelks) to different temporal patterns of risk from predatory crabs (Carcinus maenas). Prey foraging activity declined during periods of danger, but as dangerous periods became longer, prey state altered the magnitude of risk effects on prey foraging and growth, with likely consequences for community structure (trait-mediated indirect effects on basal resources, Mytilus edulis mussels), prey fitness and trophic energy transfer. Because risk is inherently variable over time and space, our results suggest that non-consumptive predator effects may be most pronounced in productive systems where prey can build energy reserves during periods of safety and then burn these reserves as ‘trophic heat’ during extended periods of danger. Understanding the interaction between behavioural (energy gain) and physiological (energy use) responses to risk may illuminate the context dependency of trait-mediated trophic cascades and help explain variation in food chain length. PMID:25339716

Composite collective decision-making.

PubMed

Czaczkes, Tomer J; Czaczkes, Benjamin; Iglhaut, Carolin; Heinze, Jürgen

2015-06-22

Individual animals are adept at making decisions and have cognitive abilities, such as memory, which allow them to hone their decisions. Social animals can also share information. This allows social animals to make adaptive group-level decisions. Both individual and collective decision-making systems also have drawbacks and limitations, and while both are well studied, the interaction between them is still poorly understood. Here, we study how individual and collective decision-making interact during ant foraging. We first gathered empirical data on memory-based foraging persistence in the ant Lasius niger. We used these data to create an agent-based model where ants may use social information (trail pheromones), private information (memories) or both to make foraging decisions. The combined use of social and private information by individuals results in greater efficiency at the group level than when either information source was used alone. The modelled ants couple consensus decision-making, allowing them to quickly exploit high-quality food sources, and combined decision-making, allowing different individuals to specialize in exploiting different resource patches. Such a composite collective decision-making system reaps the benefits of both its constituent parts. Exploiting such insights into composite collective decision-making may lead to improved decision-making algorithms. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Predator crypsis enhances behaviourally mediated indirect effects on plants by altering bumblebee foraging preferences

PubMed Central

Ings, Thomas C.; Chittka, Lars

2009-01-01

Predators of pollinators can influence pollination services and plant fitness via both consumptive (reducing pollinator density) and non-consumptive (altering pollinator behaviour) effects. However, a better knowledge of the mechanisms underlying behaviourally mediated indirect effects of predators is necessary to properly understand their role in community dynamics. We used the tripartite relationship between bumblebees, predatory crab spiders and flowers to ask whether behaviourally mediated effects are localized to flowers harbouring predators, or whether bees extend their avoidance to entire plant species. In a tightly controlled laboratory environment, bumblebees (Bombus terrestris) were exposed to a random mixture of equally rewarding yellow and white artificial flowers, but foraging on yellow flowers was very risky: bees had a 25 per cent chance of receiving a simulated predation attempt by ‘robotic’ crab spiders. As bees learnt to avoid ‘dangerous’ flowers, their foraging preferences changed and they began to visit fewer yellow flowers than expected by chance. Bees avoided spider-free yellow flowers as well as dangerous yellow flowers when spiders were more difficult to detect (the colour of yellow spiders was indistinguishable from that of yellow flowers). Therefore, this interaction between bee learning and predator crypsis could lead flower species harbouring cryptic predators to suffer from reduced reproductive success. PMID:19324797

Roosevelt elk density and social segregation: Foraging behavior and females avoiding larger groups of males

USGS Publications Warehouse

Weckerly, F.; McFarland, K.; Ricca, M.; Meyer, K.

2004-01-01

Intersexual social segregation at small spatial scales is prevalent in ruminants that are sexually dimorphic in body size. Explaining social segregation, however, from hypotheses of how intersexual size differences affects the foraging process of males and females has had mixed results. We studied whether body size influences on forage behavior, intersexual social incompatibility or both might influence social segregation in a population of Roosevelt elk (Cervus elaphus roosevelt) that declined 40% over 5 y. Most males and females in the population occurred in the same forage patches, meadows, but occupied different parts of meadows and most groups were overwhelming comprised of one sex. The extent of segregation varied slightly with changing elk density. Cropping rate, our surrogate of forage ingestion, of males in mixed-sex groups differed from males in male-only groups at high, but not low, elk density. In a prior study of intersexual social interactions it was shown that females avoided groups containing ???6 males. Therefore, we predicted that females should avoid parts of meadows where groups of males ???6 were prevalent. Across the 5 y of study this prediction held because ???5% of all females were found in parts of meadows where median aggregation sizes of males were ???6. Social segregation was coupled to body size influences on forage ingestion at high density and social incompatibility was coupled to social segregation regardless of elk density.

Fast carnivores and slow herbivores: differential foraging strategies among grizzly bears in the Canadian Arctic.

PubMed

Edwards, Mark A; Derocher, Andrew E; Hobson, Keith A; Branigan, Marsha; Nagy, John A

2011-04-01

Categorizing animal populations by diet can mask important intrapopulation variation, which is crucial to understanding a species' trophic niche width. To test hypotheses related to intrapopulation variation in foraging or the presence of diet specialization, we conducted stable isotope analysis (δ(13)C, δ(15)N) on hair and claw samples from 51 grizzly bears (Ursus arctos) collected from 2003 to 2006 in the Mackenzie Delta region of the Canadian Arctic. We examined within-population differences in the foraging patterns of males and females and the relationship between trophic position (derived from δ(15)N measurements) and individual movement. The range of δ(15)N values in hair and claw (2.0-11.0‰) suggested a wide niche width and cluster analyses indicated the presence of three foraging groups within the population, ranging from near-complete herbivory to near-complete carnivory. We found no linear relationship between home range size and trophic position when the data were continuous or when grouped by foraging behavior. However, the movement rate of females increased linearly with trophic position. We used multisource dual-isotope mixing models to determine the relative contributions of seven prey sources within each foraging group for both males and females. The mean bear dietary endpoint across all foraging groups for each sex fell toward the center of the mixing polygon, which suggested relatively well-mixed diets. The primary dietary difference across foraging groups was the proportional contribution of herbaceous foods, which decreased for both males and females from 42-76 to 0-27% and 62-81 to 0-44%, respectively. Grizzlies of the Mackenzie Delta live in extremely harsh conditions and identifying within-population diet specialization has improved our understanding of varying habitat requirements within the population.

A gravity model for the spread of a pollinator-borne plant pathogen.

PubMed

Ferrari, Matthew J; Bjørnstad, Ottar N; Partain, Jessica L; Antonovics, Janis

2006-09-01

Many pathogens of plants are transmitted by arthropod vectors whose movement between individual hosts is influenced by foraging behavior. Insect foraging has been shown to depend on both the quality of hosts and the distances between hosts. Given the spatial distribution of host plants and individual variation in quality, vector foraging patterns may therefore produce predictable variation in exposure to pathogens. We develop a "gravity" model to describe the spatial spread of a vector-borne plant pathogen from underlying models of insect foraging in response to host quality using the pollinator-borne smut fungus Microbotryum violaceum as a case study. We fit the model to spatially explicit time series of M. violaceum transmission in replicate experimental plots of the white campion Silene latifolia. The gravity model provides a better fit than a mean field model or a model with only distance-dependent transmission. The results highlight the importance of active vector foraging in generating spatial patterns of disease incidence and for pathogen-mediated selection for floral traits.

40 CFR 180.497 - Clofencet; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., except rice, sweet corn, wheat, and wild rice; forage 4.0 7/14/12 Grain, cereal, forage, fodder and straw, group 16, except rice, sweet corn, wheat, and wild rice; hay 15.0 7/14/12 Grain, cereal, forage, fodder and straw, group 16, except rice, sweet corn, wheat, and wild rice; stover 1.0 7/14/12 Grain, cereal...

40 CFR 180.497 - Clofencet; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., except rice, sweet corn, wheat, and wild rice; forage 4.0 7/14/12 Grain, cereal, forage, fodder and straw, group 16, except rice, sweet corn, wheat, and wild rice; hay 15.0 7/14/12 Grain, cereal, forage, fodder and straw, group 16, except rice, sweet corn, wheat, and wild rice; stover 1.0 7/14/12 Grain, cereal...

40 CFR 180.497 - Clofencet; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., except rice, sweet corn, wheat, and wild rice; forage 4.0 7/14/12 Grain, cereal, forage, fodder and straw, group 16, except rice, sweet corn, wheat, and wild rice; hay 15.0 7/14/12 Grain, cereal, forage, fodder and straw, group 16, except rice, sweet corn, wheat, and wild rice; stover 1.0 7/14/12 Grain, cereal...

Specialization on pollen or nectar in bumblebee foragers is not associated with ovary size, lipid reserves or sensory tuning

PubMed Central

Graystock, Peter; Hughes, William O.H.

2016-01-01

Foraging specialization allows social insects to more efficiently exploit resources in their environment. Recent research on honeybees suggests that specialization on pollen or nectar among foragers is linked to reproductive physiology and sensory tuning (the Reproductive Ground-Plan Hypothesis; RGPH). However, our understanding of the underlying physiological relationships in non-Apis bees is still limited. Here we show that the bumblebee Bombus terrestris has specialist pollen and nectar foragers, and test whether foraging specialization in B. terrestris is linked to reproductive physiology, measured as ovarian activation. We show that neither ovary size, sensory sensitivity, measured through proboscis extension response (PER), or whole-body lipid stores differed between pollen foragers, nectar foragers, or generalist foragers. Body size also did not differ between any of these three forager groups. Non-foragers had significantly larger ovaries than foragers. This suggests that potentially reproductive individuals avoid foraging. PMID:27812411

Field evidence for pervasive indirect effects of fishing on prey foraging behavior.

PubMed

Madin, Elizabeth M P; Gaines, Steven D; Warner, Robert R

2010-12-01

The indirect, ecosystem-level consequences of ocean fishing, and particularly the mechanisms driving them, are poorly understood. Most studies focus on density-mediated trophic cascades, where removal of predators alternately causes increases and decreases in abundances of lower trophic levels. However, cascades could also be driven by where and when prey forage rather than solely by prey abundance. Over a large gradient of fishing intensity in the central Pacific's remote northern Line Islands, including a nearly pristine, baseline coral reef system, we found that changes in predation risk elicit strong behavioral responses in foraging patterns across multiple prey fish species. These responses were observed as a function of both short-term ("acute") risk and longer-term ("chronic") risk, as well as when prey were exposed to model predators to isolate the effect of perceived predation risk from other potentially confounding factors. Compared to numerical prey responses, antipredator behavioral responses such as these can potentially have far greater net impacts (by occurring over entire assemblages) and operate over shorter temporal scales (with potentially instantaneous response times) in transmitting top-down effects. A rich body of literature exists on both the direct effects of human removal of predators from ecosystems and predators' effects on prey behavior. Our results draw together these lines of research and provide the first empirical evidence that large-scale human removal of predators from a natural ecosystem indirectly alters prey behavior. These behavioral changes may, in turn, drive previously unsuspected alterations in reef food webs.

Bias to pollen odors is affected by early exposure and foraging experience.

PubMed

Arenas, A; Farina, W M

2014-07-01

In many pollinating insects, foraging preferences are adjusted on the basis of floral cues learned at the foraging site. In addition, olfactory experiences gained at early adult stages might also help them to initially choose food sources. To understand pollen search behavior of honeybees, we studied how responses elicited by pollen-based odors are biased in foraging-age workers according to (i) their genetic predisposition to collect pollen, (ii) pollen related information gained during foraging and (iii) different experiences with pollen gained at early adult ages. Bees returning to the hive carrying pollen loads, were strongly biased to unfamiliar pollen bouquets when tested in a food choice device against pure odors. Moreover, pollen foragers' orientation response was specific to the odors emitted by the pollen type they were carrying on their baskets, which suggests that foragers retrieve pollen odor information to recognize rewarding flowers outside the hive. We observed that attraction to pollen odor was mediated by the exposure to a pollen diet during the first week of life. We did not observe the same attraction in foraging-age bees early exposed to an artificial diet that did not contain pollen. Contrary to the specific response observed to cues acquired during foraging, early exposure to single-pollen diets did not bias orientation response towards a specific pollen odor in foraging-age bees (i.e. bees chose equally between the exposed and the novel monofloral pollen odors). Our results show that pollen exposure at early ages together with olfactory experiences gained in a foraging context are both relevant to bias honeybees' pollen search behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

40 CFR 180.585 - Pyraflufen-ethyl; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

.../revocation date Almond, hulls 0.02 None. Cattle, meat byproducts 0.02 10/15/12 Corn, field, forage 0.01 None..., undelinted seed 0.04 None Fruit, pome, group 11-10 0.01 None. Fruit, stone, group 12 0.01 None. Grape 0.01... Soybean, forage 0.05 None Soybean, hay 0.10 None Soybean, seed 0.01 None Wheat, forage 0.02 None Wheat...

40 CFR 180.585 - Pyraflufen-ethyl; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

.../revocation date Almond, hulls 0.02 None. Cattle, meat byproducts 0.02 10/15/12 Corn, field, forage 0.01 None..., undelinted seed 0.04 None Fruit, pome, group 11-10 0.01 None. Fruit, stone, group 12 0.01 None. Grape 0.01... Soybean, forage 0.05 None Soybean, hay 0.10 None Soybean, seed 0.01 None Wheat, forage 0.02 None Wheat...

Feeding guild of non-host community members affects host-foraging efficiency of a parasitic wasp.

PubMed

De Rijk, Marjolein; Yang, Daowei; Engel, Bas; Dicke, Marcel; Poelman, Erik H

2016-06-01

Interactions between predator and prey, or parasitoid and host, are shaped by trait- and density-mediated processes involving other community members. Parasitoids that lay their eggs in herbivorous insects locate their hosts through infochemicals such as herbivore-induced plant volatiles (HIPVs) and host-produced kairomones. Hosts are frequently accompanied by non-host herbivores that are unsuitable for the parasitoid. These non-hosts may interfere with host location primarily through trait-mediated processes, by their own infochemicals, and their induction of the emission of plant volatiles. Although it is known that single non-hosts can interfere with parasitoid host location, it is still unknown whether the observed effects are due to species specific characteristics or to the feeding habits of the non-host herbivores. Here we addressed whether the feeding guild of non-host herbivores differentially affects foraging of the parasitoid Cotesia glomerata for its common host, caterpillars of Pieris brassicae feeding on Brassica oleracea plants. We used different phloem-feeding and leaf-chewing non-hosts to study their effects on host location by the parasitoid when searching for host-infested plants based on HIPVs and when searching for hosts on the plant using infochemicals. To evaluate the ultimate effect of these two phases in host location, we studied parasitism efficiency of parasitoids in small plant communities under field-tent conditions. We show that leaf-chewing non-hosts primarily affected host location through trait-mediated effects via plant volatiles, whereas phloem-feeding non-hosts exerted trait-mediated effects by affecting foraging efficiency of the parasitoid on the plant. These trait-mediated effects resulted in associational susceptibility of hosts in environments with phloem feeders and associational resistance in environments with non-host leaf chewers.

The patch distributed producer-scrounger game.

PubMed

Ohtsuka, Yasunori; Toquenaga, Yukihiko

2009-09-21

Grouping in animals is ubiquitous and thought to provide group members antipredatory advantages and foraging efficiency. However, parasitic foraging strategy often emerges in a group. The optimal parasitic policy has given rise to the producer-scrounger (PS) game model, in which producers search for food patches, and scroungers parasitize the discovered patches. The N-persons PS game model constructed by Vickery et al. (1991. Producers, scroungers, and group foraging. American Naturalist 137, 847-863) predicts the evolutionarily stable strategy (ESS) of frequency of producers (q;) that depends on the advantage of producers and the number of foragers in a group. However, the model assumes that the number of discovered patches in one time unit never exceeds one. In reality, multiple patches could be found in one time unit. In the present study, we relax this assumption and assumed that the number of discovered patches depends on the producers' variable encounter rate with patches (lambda). We show that q; strongly depends on lambda within a feasible range, although it still depends on the advantage of producer and the number of foragers in a group. The basic idea of PS game is the same as the information sharing (parasitism), because scroungers are also thought to parasitize informations of locations of food patches. Horn (1968) indicated the role of information-parasitism in animal aggregation (Horn, H.S., 1968. The adaptive significance of colonial nesting in the Brewer's blackbird (euphagus cyanocephalus). Ecology 49, 682-646). Our modified PS game model shows the same prediction as the Horn's graphical animal aggregation model; the proportion of scroungers will increase or animals should adopt colonial foraging when resource is spatiotemporally clumped, but scroungers will decrease or animals should adopt territorial foraging if the resource is evenly distributed.

The interplay between scent trails and group-mass recruitment systems in ants.

PubMed

Planqué, Robert; van den Berg, Jan Bouwe; Franks, Nigel R

2013-10-01

Large ant colonies invariably use effective scent trails to guide copious ant numbers to food sources. The success of mass recruitment hinges on the involvement of many colony members to lay powerful trails. However, many ant colonies start off as single queens. How do these same colonies forage efficiently when small, thereby overcoming the hurdles to grow large? In this paper, we study the case of combined group and mass recruitment displayed by some ant species. Using mathematical models, we explore to what extent early group recruitment may aid deployment of scent trails, making such trails available at much smaller colony sizes. We show that a competition between group and mass recruitment may cause oscillatory behaviour mediated by scent trails. This results in a further reduction of colony size to establish trails successfully.

Effects of dietary forage level and monensin on lactation performance, digestibility and fecal excretion of nutrients, and efficiency of feed nitrogen utilization of Holstein dairy cows.

PubMed

Martinez, C M; Chung, Y-H; Ishler, V A; Bailey, K W; Varga, G A

2009-07-01

Two experiments (Exp. 1 and 2) were conducted using a 4 x 4 Latin square design with 2 replications (n = 8) to evaluate effects of feeding Holstein dairy cows a total mixed ration containing 50 or 60% of ration dry matter (DM) from forages with or without supplementation of monensin. In Exp. 1, alfalfa silage (AS) was used as the major forage (55% forage DM), and corn silage (CS; 45% forage DM) was used to make up the rest of the forage portion of diets (55AS:45CS). In Exp. 2, CS was used as the major forage (70% forage DM) and alfalfa hay (AH; 30% forage DM) was used to make up the rest of the forage portion of diets (70CS:30AH). Experimental diets were arranged in a 2 x 2 factorial with 50 or 60% ration DM from forages and monensin supplemented at 0 or 300 mg/cow daily. In Exp. 1 (55AS:45CS), feeding 60% forage diets decreased DM intake (DMI; 27.3 vs. 29.6 kg/d) but maintained the same levels of milk (45.8 vs. 47.0 kg/d) compared with 50% forage diets. The efficiency of converting feed to milk or 3.5% fat-corrected milk was greater for cows fed 60% compared with 50% forage diets (1.7 vs. 1.6 kg milk or 3.5% fat-corrected milk/kg of DMI, respectively). Increasing dietary forage level from 50 to 60% of ration DM increased milk fat percentage (3.4 to 3.5%); however, adding monensin to the 60% forage diet inhibited the increase in milk fat percentage. Feeding 60% forage diets decreased feed cost, but this decrease ($0.5/head per day) in feed cost did not affect income over feed cost. Feeding 60% forage diets decreased fecal excretion of DM (10.6 to 9.6 kg/d) and nitrogen (N; 354 to 324 g/d) and improved apparent digestibility of neutral detergent fiber from 43 to 49% and apparent efficiency of feed N utilization from 32.3 to 35.9% compared with 50% forage diets. In Exp. 2 (70CS:30AH), feeding 60% forage diets decreased DMI from 29.6 to 28.2 kg but maintained the same level of milk (41.1 vs. 40.8 kg/d) and therefore increased the efficiency of converting feed to milk (1.46 vs. 1.38 kg milk/kg DMI) compared with 50% forage diets. Daily feed cost for feeding 60% forage diets was $0.3/head lower than for the 50% forage diets. Fecal excretion of DM (10.3 vs. 11.5 kg/d) was lower and fecal excretion of N (299 vs. 328 g/d) tended to be lower for 60% compared with 50% forage diets. Results from these 2 experiments suggest that a 60% forage diet consisting of either AS or CS as the major forage can be fed to high producing Holstein dairy cows without affecting milk production while improving or maintaining the efficiency of converting feed to milk and the apparent efficiency of utilization of feed N. Cows receiving a 60% forage diet had a similar or improved digestibility of nutrients with a similar or reduced fecal excretion of nutrients. Effects of monensin under the conditions of the current experiments were minimal.

Chemically mediated group formation in soil-dwelling larvae and pupae of the beetle Trypoxylus dichotomus

NASA Astrophysics Data System (ADS)

Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

2014-09-01

Many insects form groups through interactions among individuals, and these are often mediated by chemical, acoustic, or visual cues and signals. In spite of the diversity of soil-dwelling insects, their aggregation behaviour has not been examined as extensively as that of aboveground species. We investigated the aggregation mechanisms of larvae of the Japanese rhinoceros beetle Trypoxylus dichotomus, which live in groups in humus soil. In two-choice laboratory tests, 2nd- and 3rd-instar larvae gathered at conspecific larvae irrespective of the kinship. The ablation of maxillae, which bear chemosensilla, abolished aggregation behaviour. Intact larvae also exhibited aggregation behaviour towards a larval homogenate. These results suggest that larval aggregation is mediated by chemical cues. We also demonstrated that the mature larvae of T. dichotomus built their pupal cells close to a mesh bag containing a conspecific pupal cell, which indicated that larvae utilize chemical cues emanating from these cells to select the pupation site. Thus, the larvae of T. dichotomus may use chemical cues from the conspecifics in two different contexts, i.e. larval aggregation and pupation site selection. Using conspecific cues, larvae may be able to choose suitable locations for foraging or building pupal cells. The results of the present study highlight the importance of chemical information in belowground ecology.

Chemically mediated group formation in soil-dwelling larvae and pupae of the beetle Trypoxylus dichotomus.

PubMed

Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

2014-09-01

Many insects form groups through interactions among individuals, and these are often mediated by chemical, acoustic, or visual cues and signals. In spite of the diversity of soil-dwelling insects, their aggregation behaviour has not been examined as extensively as that of aboveground species. We investigated the aggregation mechanisms of larvae of the Japanese rhinoceros beetle Trypoxylus dichotomus, which live in groups in humus soil. In two-choice laboratory tests, 2nd- and 3rd-instar larvae gathered at conspecific larvae irrespective of the kinship. The ablation of maxillae, which bear chemosensilla, abolished aggregation behaviour. Intact larvae also exhibited aggregation behaviour towards a larval homogenate. These results suggest that larval aggregation is mediated by chemical cues. We also demonstrated that the mature larvae of T. dichotomus built their pupal cells close to a mesh bag containing a conspecific pupal cell, which indicated that larvae utilize chemical cues emanating from these cells to select the pupation site. Thus, the larvae of T. dichotomus may use chemical cues from the conspecifics in two different contexts, i.e. larval aggregation and pupation site selection. Using conspecific cues, larvae may be able to choose suitable locations for foraging or building pupal cells. The results of the present study highlight the importance of chemical information in belowground ecology.

Effect of fall-grazed sericea lespedeza (Lespedeza cuneata) on gastrointestinal nematode infections of growing goats.

PubMed

Mechineni, A; Kommuru, D S; Gujja, S; Mosjidis, J A; Miller, J E; Burke, J M; Ramsay, A; Mueller-Harvey, I; Kannan, G; Lee, J H; Kouakou, B; Terrill, T H

2014-08-29

High prevalence of anthelmintic-resistant gastrointestinal nematodes (GIN) in goats has increased pressure to find effective, alternative non-synthetic control methods, one of which is adding forage of the high condensed tannin (CT) legume sericea lespedeza (SL; Lespedeza cuneata) to the animal's diet. Previous work has demonstrated good efficacy of dried SL (hay, pellets) against small ruminant GIN, but information is lacking on consumption of fresh SL, particularly during the late summer-autumn period in the southern USA when perennial warm-season grass pastures are often low in quality. A study was designed to determine the effects of autumn (September-November) consumption of fresh SL forage, grass pasture (predominantly bermudagrass, BG; Cynodon dactylon), or a combination of SL+BG forage by young goats [intact male Spanish kids, 9 months old (20.7 ± 1.1 kg), n = 10/treatment group] on their GIN infection status. Three forage paddocks (0.40 ha) were set up at the Fort Valley State University Agricultural Research Station (Fort Valley, GA) for an 8-week trial. The goats in each paddock were supplemented with a commercial feed pellet at 0.45 kg/head/d for the first 4 weeks of the trial, and 0.27 kg/head/d for the final 4 weeks. Forage samples taken at the start of the trial were analyzed for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) content, and a separate set of SL samples was analyzed for CT in leaves, stems, and whole plant using the benzyl mercaptan thiolysis method. Animal weights were taken at the start and end of the trial, and fecal and blood samples were collected weekly for determination of fecal egg counts (FEC) and packed cell volume (PCV), respectively. Adult GIN was recovered from the abomasum and small intestines of all goats at the end of the experiment for counting and speciation. The CP levels were highest for SL forage, intermediate for SL+BG, and lowest for BG forage samples, while NDF and ADF values were the opposite, with highest levels in BG and lowest in SL forage samples. Sericea lespedeza leaves had more CT than stems (16.0 g vs. 3.3g/100g dry weight), a slightly higher percentage of PDs (98% vs. 94%, respectively) and polymers of larger mean degrees of polymerization (42 vs. 18, respectively). There were no differences in average daily gain or blood PCV between the treatment groups, but SL goats had lower FEC (P < 0.05) than the BG or SL+BG forage goats throughout most of the trial. The SL+BG goats had lower FEC than the BG forage animals by the end of the trial (week 8, P < 0.05). The SL goats had lower numbers (P < 0.05) of male Haemonchus contortus and tended to have fewer female (P < 0.10) and total (P < 0.07) H. contortus compared with the BG goats. The predominant GIN in all the goats was Trichostrongylus colubriformis (73% of total GIN). As a low-input forage with activity against pathogenic GIN (H. contortus), SL has a potential to reduce producers' dependence upon synthetic anthelmintics and also to fill the autumn 'window' in good-quality fresh forages for goat grazing in the southern USA. Copyright © 2014 Elsevier B.V. All rights reserved.

Hunter-Gatherer Energetics and Human Obesity

PubMed Central

Pontzer, Herman; Raichlen, David A.; Wood, Brian M.; Mabulla, Audax Z. P.; Racette, Susan B.; Marlowe, Frank W.

2012-01-01

Western lifestyles differ markedly from those of our hunter-gatherer ancestors, and these differences in diet and activity level are often implicated in the global obesity pandemic. However, few physiological data for hunter-gatherer populations are available to test these models of obesity. In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups. The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure. We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences. PMID:22848382

Hunter-gatherer energetics and human obesity.

PubMed

Pontzer, Herman; Raichlen, David A; Wood, Brian M; Mabulla, Audax Z P; Racette, Susan B; Marlowe, Frank W

2012-01-01

Western lifestyles differ markedly from those of our hunter-gatherer ancestors, and these differences in diet and activity level are often implicated in the global obesity pandemic. However, few physiological data for hunter-gatherer populations are available to test these models of obesity. In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg(-1) m(-1)) and resting (kcal kg(-1) s(-1)) were also similar among Hadza and Western groups. The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure. We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences.

Determination of Tropical Forage Preferences Using Two Offering Methods in Rabbits

PubMed Central

Safwat, A. M.; Sarmiento-Franco, L.; Santos-Ricalde, R. H.; Nieves, D.

2014-01-01

Two methods of feed preference trials were compared to evaluate the acceptability of 5 fresh foliages: Leucaena leucocephala, Moringa oleifera, Portulaca oleracea, Guazuma ulmifolia, and Brosimum alicastrum that was included as control. The evaluation included chemical analyses and forage intake by rabbits. The first method was a cafeteria trial; 12 California growing rabbits aged 8 wk, allocated in individual cages, were offered the five forage plants at the same time inside the cage, while in the second trial 60 California growing rabbits aged 8 wk, allocated individually, were randomly distributed into 5 experimental groups (n = 12/group); for each group just one forage species was offered at a time. The testing period for each method lasted for 7 d, preceded by one week of adaptation. The results showed that B. alicastrum and L. lecocephala were the most preferred forages while on the contrary G. ulmifolia was the least preferred one by rabbits. The results also revealed that the CV% value for the 2nd method (16.32%), which the tested forages were presented separately to rabbits, was lower and methodologically more acceptable than such value for the 1st method (34.28%), which all forages were presented together at the same time. It can be concluded that a range of tropical forages were consumed in acceptable quantities by rabbits, suggesting that diets based on such forages with a concentrate supplement could be used successfully for rabbit production. However, growth performance studies are still needed before recommendations could be made on appropriate ration formulations for commercial use. PMID:25049983

A new navigational mechanism mediated by ant ocelli.

PubMed

Schwarz, Sebastian; Wystrach, Antoine; Cheng, Ken

2011-12-23

Many animals rely on path integration for navigation and desert ants are the champions. On leaving the nest, ants continuously integrate their distance and direction of travel so that they always know their current distance and direction from the nest and can take a direct path to home. Distance information originates from a step-counter and directional information is based on a celestial compass. So far, it has been assumed that the directional information obtained from ocelli contribute to a single global path integrator, together with directional information from the dorsal rim area (DRA) of the compound eyes and distance information from the step-counter. Here, we show that ocelli mediate a distinct compass from that mediated by the compound eyes. After travelling a two-leg outbound route, untreated foragers headed towards the nest direction, showing that both legs of the route had been integrated. In contrast, foragers with covered compound eyes but uncovered ocelli steered in the direction opposite to the last leg of the outbound route. Our findings suggest that, unlike the DRA, ocelli cannot by themselves mediate path integration. Instead, ocelli mediate a distinct directional system, which buffers the most recent leg of a journey.

Spatiotemporal resource distribution and foraging strategies of ants (Hymenoptera: Formicidae)

PubMed Central

Lanan, Michele

2014-01-01

The distribution of food resources in space and time is likely to be an important factor governing the type of foraging strategy used by ants. However, no previous systematic attempt has been made to determine whether spatiotemporal resource distribution is in fact correlated with foraging strategy across the ants. In this analysis, I present data compiled from the literature on the foraging strategy and food resource use of 402 species of ants from across the phylogenetic tree. By categorizing the distribution of resources reported in these studies in terms of size relative to colony size, spatial distribution relative to colony foraging range, frequency of occurrence in time relative to worker life span, and depletability (i.e., whether the colony can cause a change in resource frequency), I demonstrate that different foraging strategies are indeed associated with specific spatiotemporal resource attributes. The general patterns I describe here can therefore be used as a framework to inform predictions in future studies of ant foraging behavior. No differences were found between resources collected via short-term recruitment strategies (group recruitment, short-term trails, and volatile recruitment), whereas different resource distributions were associated with solitary foraging, trunk trails, long-term trail networks, group raiding, and raiding. In many cases, ant species use a combination of different foraging strategies to collect diverse resources. It is useful to consider these foraging strategies not as separate options but as modular parts of the total foraging effort of a colony. PMID:25525497

Foraging behavior of redheads (Aythya americana) wintering in Texas and Louisiana

USGS Publications Warehouse

Woodin, M.C.; Michot, T.C.

2006-01-01

Redheads, Aythya americana, concentrate in large numbers annually in traditional wintering areas along the western and northern rim of the Gulf of Mexico. Two of these areas are the Laguna Madre of Texas and Chandeleur Sound of Louisiana. We collected data on 54,340 activities from 103 redhead flocks in Texas and 51,650 activities from 57 redhead flocks in Louisiana. Males and females fed similarly, differing neither in levels of feeding (percent of all birds in flock that were feeding) (p>0.90) nor in percentages of birds feeding by diving, tipping, dipping, or gleaning from the surface (p>0.10). The foraging level of redheads in the upper Laguna Madre region was relatively constant throughout two winters. Foraging of redheads in early winter in Louisiana was significantly greater than redhead foraging in the upper Laguna Madre, but by late winter, foraging by redheads in Louisiana had declined to the same level as that shown by redheads foraging in the upper Laguna Madre. The overall foraging level of redheads from Chandeleur Sound was greater (41%) than that of redheads in the upper Laguna Madre (26%), yet it was quite similar to the 46% foraging level reported for redheads from the lower Laguna Madre. Redheads in the upper Laguna Madre region of Texas fed more by diving than did those in the Chandeleur Sound and the lower Laguna Madre. Diving increased in frequency in late winter. Greater reliance by redheads on diving in January and February indicates that the birds altered their foraging to feed in deeper water, suggesting that the large concentrations of redheads staging at this time for spring migration may have displaced some birds to alternative foraging sites. Our results imply that the most likely period for food resources to become limiting for wintering redheads is when they are staging in late winter. ?? Springer 2006.

The Trail Less Traveled: Individual Decision-Making and Its Effect on Group Behavior

PubMed Central

Lanan, Michele C.; Dornhaus, Anna; Jones, Emily I.; Waser, Andrew; Bronstein, Judith L.

2012-01-01

Social insect colonies are complex systems in which the interactions of many individuals lead to colony-level collective behaviors such as foraging. However, the emergent properties of collective behaviors may not necessarily be adaptive. Here, we examine symmetry breaking, an emergent pattern exhibited by some social insects that can lead colonies to focus their foraging effort on only one of several available food patches. Symmetry breaking has been reported to occur in several ant species. However, it is not clear whether it arises as an unavoidable epiphenomenon of pheromone recruitment, or whether it is an adaptive behavior that can be controlled through modification of the individual behavior of workers. In this paper, we used a simulation model to test how symmetry breaking is affected by the degree of non-linearity of recruitment, the specific mechanism used by individuals to choose between patches, patch size, and forager number. The model shows that foraging intensity on different trails becomes increasingly asymmetric as the recruitment response of individuals varies from linear to highly non-linear, supporting the predictions of previous work. Surprisingly, we also found that the direction of the relationship between forager number (i.e., colony size) and asymmetry varied depending on the specific details of the decision rule used by individuals. Limiting the size of the resource produced a damping effect on asymmetry, but only at high forager numbers. Variation in the rule used by individual ants to choose trails is a likely mechanism that could cause variation among the foraging behaviors of species, and is a behavior upon which selection could act. PMID:23112880

The importance of delineating networks by activity type in bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida.

PubMed

Gazda, Stefanie; Iyer, Swami; Killingback, Timothy; Connor, Richard; Brault, Solange

2015-03-01

Network analysis has proved to be a valuable tool for studying the behavioural patterns of complex social animals. Often such studies either do not distinguish between different behavioural states of the organisms or simply focus attention on a single behavioural state to the exclusion of all others. In either of these approaches it is impossible to ascertain how the behavioural patterns of individuals depend on the type of activity they are engaged in. Here we report on a network-based analysis of the behavioural associations in a population of bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida. We consider three distinct behavioural states-socializing, travelling and foraging-and analyse the association networks corresponding to each activity. Moreover, in constructing the different activity networks we do not simply record a spatial association between two individuals as being either present or absent, but rather quantify the degree of any association, thus allowing us to construct weighted networks describing each activity. The results of these weighted activity networks indicate that networks can reveal detailed patterns of bottlenose dolphins at the population level; dolphins socialize in large groups with preferential associations; travel in small groups with preferential associates; and spread out to forage in very small, weakly connected groups. There is some overlap in the socialize and travel networks but little overlap between the forage and other networks. This indicates that the social bonds maintained in other activities are less important as they forage on dispersed, solitary prey. The overall network, not sorted by activity, does not accurately represent any of these patterns.

Analysis of Inter- and Intra-individual Variation in Foraging Habits of the Endangered Hawaiian Petrel Using Stables Isotopes

NASA Astrophysics Data System (ADS)

Morra, K. E.; Ostrom, P. H.; Wiley, A. E.; James, H. F.; Stricker, C. A.; Gandhi, H.

2014-12-01

Stable isotope analysis of the endangered Hawaiian petrel's (Pterodroma sandwichensis, HAPE) feathers provides otherwise intractable information regarding non-breeding season foraging habits. Adult HAPE spend 3.5-6 months at sea during the non-breeding season, at which time they sequentially molt their flight feathers. Because feathers are metabolically inert once synthesized, they capture isotopic signals while they are grown, providing an opportunity to study foraging habits over time. Here we use stable hydrogen (δD), carbon (δ13C) and nitrogen (δ15N) isotopes to assess variation in foraging habits within and between individuals, and among four breeding colonies. δD is an indicator of prevalence of fish vs. invertebrates in the diet. In one analysis, we observed large variation in feather δD (125‰), with adults from Maui and Kauai having significantly higher δD values than corresponding hatch-year birds, indicating significant dietary differences between age groups. In a second analysis, we utilized δ13C and δ15N of Hawaii, Maui and Lanai adults, values which vary with trophic level and also at the base of the food web across HAPE's foraging range, potentially revealing information about feeding location, as well as diet. Furthermore, because the sequence of molt is known, we are able to determine whether individual foraging specialization (continued use of the same foraging behavior over time) exists in this species. To do this, we analyzed two primary feathers, P1 and P6, which reflect the beginning and the middle of the non-breeding season, respectively. We did not find significant differences in δ13C or δ15N between P1 and P6, suggesting consistent foraging habits within individuals over time. This provides evidence that individual foraging specialization exists within these populations. Analysis of a secondary feather grown late in the molt sequence would further illuminate the extent of foraging specialization. Finally, δ15N differs significantly between Hawaii and Maui adults, suggesting foraging segregation between these two populations. HAPE may be sensitive to changes in prey availability, given evidence of foraging specialization. However, conserving HAPE populations with apparently different foraging habits may be critical to preserve ecological diversity within the species.

Evidence for ship noise impacts on humpback whale foraging behaviour.

PubMed

Blair, Hannah B; Merchant, Nathan D; Friedlaender, Ari S; Wiley, David N; Parks, Susan E

2016-08-01

Noise from shipping activity in North Atlantic coastal waters has been steadily increasing and is an area of growing conservation concern, as it has the potential to disrupt the behaviour of marine organisms. This study examines the impacts of ship noise on bottom foraging humpback whales (Megaptera novaeangliae) in the western North Atlantic. Data were collected from 10 foraging whales using non-invasive archival tags that simultaneously recorded underwater movements and the acoustic environment at the whale. Using mixed models, we assess the effects of ship noise on seven parameters of their feeding behaviours. Independent variables included the presence or absence of ship noise and the received level of ship noise at the whale. We found significant effects on foraging, including slower descent rates and fewer side-roll feeding events per dive with increasing ship noise. During 5 of 18 ship passages, dives without side-rolls were observed. These findings indicate that humpback whales on Stellwagen Bank, an area with chronically elevated levels of shipping traffic, significantly change foraging activity when exposed to high levels of ship noise. This measureable reduction in within-dive foraging effort of individual whales could potentially lead to population-level impacts of shipping noise on baleen whale foraging success. © 2016 The Author(s).

Common carp disrupt ecosystem structure and function through middle-out effects

USGS Publications Warehouse

Kaemingk, Mark A.; Jolley, Jeffrey C.; Paukert, Craig P.; Willis, David W.; Henderson, Kjetil R.; Holland, Richard S.; Wanner, Greg A.; Lindvall, Mark L.

2016-01-01

Middle-out effects or a combination of top-down and bottom-up processes create many theoretical and empirical challenges in the realm of trophic ecology. We propose using specific autecology or species trait (i.e. behavioural) information to help explain and understand trophic dynamics that may involve complicated and non-unidirectional trophic interactions. The common carp (Cyprinus carpio) served as our model species for whole-lake observational and experimental studies; four trophic levels were measured to assess common carp-mediated middle-out effects across multiple lakes. We hypothesised that common carp could influence aquatic ecosystems through multiple pathways (i.e. abiotic and biotic foraging, early life feeding, nutrient). Both studies revealed most trophic levels were affected by common carp, highlighting strong middle-out effects likely caused by common carp foraging activities and abiotic influence (i.e. sediment resuspension). The loss of water transparency, submersed vegetation and a shift in zooplankton dynamics were the strongest effects. Trophic levels furthest from direct pathway effects were also affected (fish life history traits). The present study demonstrates that common carp can exert substantial effects on ecosystem structure and function. Species capable of middle-out effects can greatly modify communities through a variety of available pathways and are not confined to traditional top-down or bottom-up processes.

Consistent Individual Differences Drive Collective Behavior and Group Functioning of Schooling Fish.

PubMed

Jolles, Jolle W; Boogert, Neeltje J; Sridhar, Vivek H; Couzin, Iain D; Manica, Andrea

2017-09-25

The ubiquity of consistent inter-individual differences in behavior ("animal personalities") [1, 2] suggests that they might play a fundamental role in driving the movements and functioning of animal groups [3, 4], including their collective decision-making, foraging performance, and predator avoidance. Despite increasing evidence that highlights their importance [5-16], we still lack a unified mechanistic framework to explain and to predict how consistent inter-individual differences may drive collective behavior. Here we investigate how the structure, leadership, movement dynamics, and foraging performance of groups can emerge from inter-individual differences by high-resolution tracking of known behavioral types in free-swimming stickleback (Gasterosteus aculeatus) shoals. We show that individual's propensity to stay near others, measured by a classic "sociability" assay, was negatively linked to swim speed across a range of contexts, and predicted spatial positioning and leadership within groups as well as differences in structure and movement dynamics between groups. In turn, this trait, together with individual's exploratory tendency, measured by a classic "boldness" assay, explained individual and group foraging performance. These effects of consistent individual differences on group-level states emerged naturally from a generic model of self-organizing groups composed of individuals differing in speed and goal-orientedness. Our study provides experimental and theoretical evidence for a simple mechanism to explain the emergence of collective behavior from consistent individual differences, including variation in the structure, leadership, movement dynamics, and functional capabilities of groups, across social and ecological scales. In addition, we demonstrate individual performance is conditional on group composition, indicating how social selection may drive behavioral differentiation between individuals. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Experimental field study of problem-solving using tools in free-ranging capuchins (Sapajus nigritus, formerly Cebus nigritus).

PubMed

Garber, P A; Gomes, D F; Bicca-Marques, J C

2012-04-01

Some populations of capuchins are reported to use tools to solve foraging problems in the wild. In most cases, this involves the act of pounding and digging. The use of probing tools by wild capuchins is considerably less common. Here we report on the results of an experimental field study conducted in southern Brazil designed to examine the ability of wild black-horned capuchins (Sapajus nigritus) to use a wooden dowel as a lever or a probe to obtain an embedded food reward. A group of eight capuchins was presented with two experimental platforms, each housing a clear Plexiglas box containing two bananas on a shelf and four inserted dowels. Depending on the conditions of the experiment, the capuchins were required either to pull (Condition I) or push (Conditions II and III) the dowels, in order to dislodge the food reward from the shelf so that it could be manually retrieved. In Condition I, four individuals spontaneously solved the foraging problem by pulling the dowels in 25% (72/291) of visits. In Conditions II and III, however, no capuchin successfully pushed the dowels forward to obtain the food reward. During these latter two experimental conditions, the capuchins continued to pull the dowels (41/151 or 27% of visits), even though this behavior did not result in foraging success. The results of these field experiments are consistent with an identical study conducted on wild Cebus capucinus in Costa Rica, and suggest that when using an external object as a probe to solve a foraging problem, individual capuchins were able to rapidly learn an association between the tool and the food reward, but failed to understand exactly how the tool functioned in accomplishing the task. The results also suggest that once a capuchin learned to solve this tool-mediated foraging problem, the individual persisted in using the same solution even in the face of repeated failure (slow rate of learning extinction). © 2011 Wiley Periodicals, Inc.

Skills, division of labour and economies of scale among Amazonian hunters and South Indian honey collectors.

PubMed

Hooper, Paul L; Demps, Kathryn; Gurven, Michael; Gerkey, Drew; Kaplan, Hillard S

2015-12-05

In foraging and other productive activities, individuals make choices regarding whether and with whom to cooperate, and in what capacities. The size and composition of cooperative groups can be understood as a self-organized outcome of these choices, which are made under local ecological and social constraints. This article describes a theoretical framework for explaining the size and composition of foraging groups based on three principles: (i) the sexual division of labour; (ii) the intergenerational division of labour; and (iii) economies of scale in production. We test predictions from the theory with data from two field contexts: Tsimane' game hunters of lowland Bolivia, and Jenu Kuruba honey collectors of South India. In each case, we estimate the impacts of group size and individual group members' effort on group success. We characterize differences in the skill requirements of different foraging activities and show that individuals participate more frequently in activities in which they are more efficient. We evaluate returns to scale across different resource types and observe higher returns at larger group sizes in foraging activities (such as hunting large game) that benefit from coordinated and complementary roles. These results inform us that the foraging group size and composition are guided by the motivated choice of individuals on the basis of relative efficiency, benefits of cooperation, opportunity costs and other social considerations. © 2015 The Author(s).

Fall-grown oat to extend the fall grazing season for replacement dairy heifers.

PubMed

Coblentz, W K; Brink, G E; Hoffman, P C; Esser, N M; Bertram, M G

2014-03-01

Our objective was to assess the pasture productivity and forage characteristics of 2 fall-grown oat (Avena sativa L.) cultivars, specifically for extending the grazing season and reducing reliance on harvested forages by replacement dairy heifers. A total of 160 gravid Holstein heifers (80 heifers/yr) were stratified by weight, and assigned to 1 of 10 identical research pens (8 heifers/pen). Initial body weights were 480 ± 43.5 kg in 2011 and 509 ± 39.4 kg in 2012. During both years of the trial, four 1.0-ha pasture replicates were seeded in August with Ogle oat (Schumitsch Seed Inc., Antigo, WI), and 4 separate, but similarly configured, pasture replicates were seeded with Forage Plus oat (Kratz Farms, Slinger, WI). Heifer groups were maintained as units, assigned to specific pastures, and then allowed to graze fall-oat pastures for 6h daily before returning to the barn, where they were offered a forage-based basal total mixed ration. Two heifer groups were retained in confinement (without grazing) as controls and offered the identical total mixed ration as pasture groups. During 2011, available forage mass increased with strong linear and quadratic effects for both cultivars, peaking at almost 9 Mg/ha on October 31. In contrast, forage mass was not affected by evaluation date in 2012, remaining ≤ 2,639 kg/ha across all dates because of droughty climatic conditions. During 2012, Ogle exhibited greater forage mass than Forage Plus across all sampling dates (2,678 vs. 1,856 kg/ha), largely because of its more rapid maturation rate and greater canopy height. Estimates of energy density for oat forage ranged from 59.6 to 69.1% during 2011, and ranged narrowly from 68.4 to 70.4% during 2012. For 2011, responses for both cultivars had strong quadratic character, in which the most energy-dense forages occurred in mid November, largely due to accumulation of water-soluble carbohydrates that reached maximum concentrations of 18.2 and 15.1% for Forage Plus and Ogle, respectively. Across the 2-yr trial, average daily gain for grazing heifer groups tended to be greater than heifers remaining in confinement (0.85 vs. 0.74 kg/d), but both management strategies produced weight gains within reasonable proximity to normal targets for heifers in this weight range. Fall-grown oat should be managed as stockpiled forage for deferred grazing, and good utilization of fall-oat forage can be accomplished by a one-time removal of standing forage, facilitated by a single lead wire advanced daily to prevent waste. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Chaos-order transition in foraging behavior of ants.

PubMed

Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

2014-06-10

The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants' physical abilities, and ants' knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal.

Chaos–order transition in foraging behavior of ants

PubMed Central

Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

2014-01-01

The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants’ physical abilities, and ants’ knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal. PMID:24912159

The dynamics of foraging trails in the tropical arboreal ant Cephalotes goniodontus.

PubMed

Gordon, Deborah M

2012-01-01

The foraging behavior of the arboreal turtle ant, Cephalotes goniodontus, was studied in the tropical dry forest of western Mexico. The ants collected mostly plant-derived food, including nectar and fluids collected from the edges of wounds on leaves, as well as caterpillar frass and lichen. Foraging trails are on small pieces of ephemeral vegetation, and persist in exactly the same place for 4-8 days, indicating that food sources may be used until they are depleted. The species is polydomous, occupying many nests which are abandoned cavities or ends of broken branches in dead wood. Foraging trails extend from trees with nests to trees with food sources. Observations of marked individuals show that each trail is travelled by a distinct group of foragers. This makes the entire foraging circuit more resilient if a path becomes impassable, since foraging in one trail can continue while a different group of ants forms a new trail. The colony's trails move around the forest from month to month; from one year to the next, only one colony out of five was found in the same location. There is continual searching in the vicinity of trails: ants recruited to bait within 3 bifurcations of a main foraging trail within 4 hours. When bait was offered on one trail, to which ants recruited, foraging activity increased on a different trail, with no bait, connected to the same nest. This suggests that the allocation of foragers to different trails is regulated by interactions at the nest.

Diffusion of novel foraging behaviour in Amazon parrots through social learning.

PubMed

Morales Picard, Alejandra; Hogan, Lauren; Lambert, Megan L; Wilkinson, Anna; Seed, Amanda M; Slocombe, Katie E

2017-03-01

While social learning has been demonstrated in species across many taxa, the role it plays in everyday foraging decisions is not well understood. Investigating social learning during foraging could shed light on the emergence of cultural variation in different groups. We used an open diffusion experiment to examine the spread of a novel foraging technique in captive Amazon parrots. Three groups were tested using a two-action foraging box, including experimental groups exposed to demonstrators using different techniques and control birds. We also examined the influence of agonistic and pilfering behaviour on task acquisition. We found evidence of social learning: more experimental birds than control birds interacted with and opened the box. The birds were, however, no more likely to use the demonstrated technique than the non-demonstrated one, making local or stimulus enhancement the most likely mechanism. Exhibiting aggression was positively correlated with box opening, whilst receiving aggression did not reduce motivation to engage with the box, indicating that willingness to defend access to the box was important in task acquisition. Pilfering food and success in opening the box were also positively correlated; however, having food pilfered did not affect victims' motivation to interact with the box. In a group context, pilfering may promote learning of new foraging opportunities. Although previous studies have demonstrated that psittacines are capable of imitation, in this naturalistic set-up there was no evidence that parrots copied the demonstrated opening technique. Foraging behaviour in wild populations of Amazons could therefore be facilitated by low-fidelity social learning mechanisms.

Foraging habits in a generalist predator: sex and age influence habitat selection and resource use among bottlenose dolphins (Tursiops truncatus)

USGS Publications Warehouse

Sam Rossman,; McCabe, Elizabeth Berens; Nelio B. Barros,; Hasand Gandhi,; Peggy H. Ostrom,; Stricker, Craig A.; Randall S. Wells,

2015-01-01

This study examines resource use (diet, habitat use, and trophic level) within and among demographic groups (males, females, and juveniles) of bottlenose dolphins (Tursiops truncatus). We analyzed the δ13C and δ15N values of 15 prey species constituting 84% of the species found in stomach contents. We used these data to establish a trophic enrichment factor (TEF) to inform dietary analysis using a Bayesian isotope mixing model. We document a TEF of 0‰ and 2.0‰ for δ13C and δ15N, respectively. The dietary results showed that all demographic groups relied heavily on low trophic level seagrass-associated prey. Bayesian standard ellipse areas (SEAb) were calculated to assess diversity in resource use. The SEAb of females was nearly four times larger than that of males indicating varied resource use, likely a consequence of small home ranges and habitat specialization. Juveniles possessed an intermediate SEAb, generally feeding at a lower trophic level compared to females, potentially an effect of natal philopatry and immature foraging skills. The small SEAb of males reflects a high degree of specialization on seagrass associated prey. Patterns in resource use by the demographic groups are likely linked to differences in the relative importance of social and ecological factors.

Effect of Saccharomyces cerevisiae on alfalfa nutrient degradation characteristics and rumen microbial populations of steers fed diets with different concentrate-to-forage ratios.

PubMed

Ding, Gengzhi; Chang, Ying; Zhao, Liping; Zhou, Zhenming; Ren, Liping; Meng, Qingxiang

2014-01-01

Live yeast (Saccharomyces cerevisiae) constitutes an effective additive for animal production; its probiotic effect may be related to the concentrate-to-forage ratio (CTFR). The objective of this study was to assess the effects of S. cerevisiae (SC) on fiber degradation and rumen microbial populations in steers fed diets with different levels of dietary concentrate. Ten Simmental × Local crossbred steers (450 ± 50 kg BW) were assigned to a control group or an SC group. Both groups were fed the same basal diet but the SC group received SC supplementation (8 × 10(9) cfu/h/d through the ruminal fistula) following a two-period crossover design. Each period consisted of four phases, each of which lasted 17 d: 10 d for dietary adaptation, 6 d for degradation study, and 1 d for rumen sample collection. From the 1(st) to the 4(th) phase, steers were fed in a stepwise fashion with increasing CTFRs, i.e., 30:70, 50:50, 70:30, and 90:10. The kinetics of dry matter and fiber degradation of alfalfa pellets were evaluated; the rumen microbial populations were detected using real-time PCR. The results revealed no significant (P > 0.05) interactions between dietary CTFR and SC for most parameters. Dietary CTFR had a significant effect (P < 0.01) on degradation characteristics of alfalfa pellets and the copies of rumen microorganism; the increasing concentrate level resulted in linear, quadratic or cubic variation trend for these parameters. SC supplementation significantly (P < 0.05) affected dry matter (DM) and neutral detergent fiber (NDF) degradation rates (c DM, c NDF) and NDF effective degradability (EDNDF). Compared with the control group, there was an increasing trend of rumen fungi and protozoa in SC group (P < 0.1); copies of total bacteria in SC group were significantly higher (P < 0.05). Additionally, percentage of Ruminobacter amylophilus was significantly lower (P < 0.05) but percentage of Selenomonas ruminantium was significantly higher (P < 0.05) in the SC group. In a word, dietary CTFR had a significant effect on degradation characteristics of forage and rumen microbial population. S. cerevisiae had positive effects on DM and NDF degradation rate or effective degradability of forage; S. cerevisiae increased rumen total bacteria, fungi, protozoa, and lactate-utilizing bacteria but reduced starch-degrading and lactate-producing bacteria.

Foraging preferences influence microplastic ingestion by six marine fish species from the Texas Gulf Coast.

PubMed

Peters, Colleen A; Thomas, Peyton A; Rieper, Kaitlyn B; Bratton, Susan P

2017-11-15

This study evaluated the influence of foraging preferences on microplastic ingestion by six marine fish species from the Texas Gulf Coast. A total of 1381 fish were analyzed and 42.4% contained ingested microplastic, inclusive of fiber (86.4%), microbead (12.9% %), and fragment (<1.0%) forms. Despite a substantial overlap in diet, ordination of ingested prey items clustered samples into distinctive species groupings, reflective of the foraging gradient among species. Orthopristis chrysoptera displayed the lowest overall frequency of microplastic ingestion and the most distinctive ordination grouping, indicating their selective invertebrate foraging preferences. Cluster analysis of O. chrysoptera most closely classified microplastic with the ingestion of benthic invertebrates, whereas the ingestion of microplastic by all other species most closely classified with the ingestion of vegetation and shrimp. O. chrysoptera, as selective invertebrate foragers, are less likely to ingest microplastics than species exhibiting generalist foraging preferences and methods of prey capture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Role of social interactions in dynamic patterns of resource patches and forager aggregation

PubMed Central

Tania, Nessy; Vanderlei, Ben; Heath, Joel P.; Edelstein-Keshet, Leah

2012-01-01

The dynamics of resource patches and species that exploit such patches are of interest to ecologists, conservation biologists, modelers, and mathematicians. Here we consider how social interactions can create unique, evolving patterns in space and time. Whereas simple prey taxis (with consumable prey) promotes spatial uniform distributions, here we show that taxis in producer–scrounger groups can lead to pattern formation. We consider two types of foragers: those that search directly (“producers”) and those that exploit other foragers to find food (“scroungers” or exploiters). We show that such groups can sustain fluctuating spatiotemporal patterns, akin to “waves of pursuit.” Investigating the relative benefits to the individuals, we observed conditions under which either strategy leads to enhanced success, defined as net food consumption. Foragers that search for food directly have an advantage when food patches are localized. Those that seek aggregations of group mates do better when their ability to track group mates exceeds the foragers’ food-sensing acuity. When behavioral switching or reproductive success of the strategies is included, the relative abundance of foragers and exploiters is dynamic over time, in contrast with classic models that predict stable frequencies. Our work shows the importance of considering two-way interaction—i.e., how food distribution both influences and is influenced by social foraging and aggregation of predators. PMID:22745167

Ant-like task allocation and recruitment in cooperative robots

NASA Astrophysics Data System (ADS)

Krieger, Michael J. B.; Billeter, Jean-Bernard; Keller, Laurent

2000-08-01

One of the greatest challenges in robotics is to create machines that are able to interact with unpredictable environments in real time. A possible solution may be to use swarms of robots behaving in a self-organized manner, similar to workers in an ant colony. Efficient mechanisms of division of labour, in particular series-parallel operation and transfer of information among group members, are key components of the tremendous ecological success of ants. Here we show that the general principles regulating division of labour in ant colonies indeed allow the design of flexible, robust and effective robotic systems. Groups of robots using ant-inspired algorithms of decentralized control techniques foraged more efficiently and maintained higher levels of group energy than single robots. But the benefits of group living decreased in larger groups, most probably because of interference during foraging. Intriguingly, a similar relationship between group size and efficiency has been documented in social insects. Moreover, when food items were clustered, groups where robots could recruit other robots in an ant-like manner were more efficient than groups without information transfer, suggesting that group dynamics of swarms of robots may follow rules similar to those governing social insects.

Measurements of Chlorpyrifos Levels in Forager Bees and Comparison with Levels that Disrupt Honey Bee Odor-Mediated Learning Under Laboratory Conditions.

PubMed

Urlacher, Elodie; Monchanin, Coline; Rivière, Coraline; Richard, Freddie-Jeanne; Lombardi, Christie; Michelsen-Heath, Sue; Hageman, Kimberly J; Mercer, Alison R

2016-02-01

Chlorpyrifos is an organophosphate pesticide used around the world to protect food crops against insects and mites. Despite guidelines for chlorpyrifos usage, including precautions to protect beneficial insects, such as honeybees from spray drift, this pesticide has been detected in bees in various countries, indicating that exposure still occurs. Here, we examined chlorpyrifos levels in bees collected from 17 locations in Otago, New Zealand, and compared doses of this pesticide that cause sub-lethal effects on learning performance under laboratory conditions with amounts of chlorpyrifos detected in the bees in the field. The pesticide was detected at 17 % of the sites sampled and in 12 % of the colonies examined. Amounts detected ranged from 35 to 286 pg.bee(-1), far below the LD50 of ~100 ng.bee(-1). We detected no adverse effect of chlorpyrifos on aversive learning, but the formation and retrieval of appetitive olfactory memories was severely affected. Chlorpyrifos fed to bees in amounts several orders of magnitude lower than the LD50, and also lower than levels detected in bees, was found to slow appetitive learning and reduce the specificity of memory recall. As learning and memory play a central role in the behavioral ecology and communication of foraging bees, chlorpyrifos, even in sublethal doses, may threaten the success and survival of this important insect pollinator.

Army ants dynamically adjust living bridges in response to a cost-benefit trade-off.

PubMed

Reid, Chris R; Lutz, Matthew J; Powell, Scott; Kao, Albert B; Couzin, Iain D; Garnier, Simon

2015-12-08

The ability of individual animals to create functional structures by joining together is rare and confined to the social insects. Army ants (Eciton) form collective assemblages out of their own bodies to perform a variety of functions that benefit the entire colony. Here we examine ‟bridges" of linked individuals that are constructed to span gaps in the colony's foraging trail. How these living structures adjust themselves to varied and changing conditions remains poorly understood. Our field experiments show that the ants continuously modify their bridges, such that these structures lengthen, widen, and change position in response to traffic levels and environmental geometry. Ants initiate bridges where their path deviates from their incoming direction and move the bridges over time to create shortcuts over large gaps. The final position of the structure depended on the intensity of the traffic and the extent of path deviation and was influenced by a cost-benefit trade-off at the colony level, where the benefit of increased foraging trail efficiency was balanced by the cost of removing workers from the foraging pool to form the structure. To examine this trade-off, we quantified the geometric relationship between costs and benefits revealed by our experiments. We then constructed a model to determine the bridge location that maximized foraging rate, which qualitatively matched the observed movement of bridges. Our results highlight how animal self-assemblages can be dynamically modified in response to a group-level cost-benefit trade-off, without any individual unit's having information on global benefits or costs.

Army ants dynamically adjust living bridges in response to a cost–benefit trade-off

PubMed Central

Reid, Chris R.; Lutz, Matthew J.; Powell, Scott; Kao, Albert B.; Couzin, Iain D.; Garnier, Simon

2015-01-01

The ability of individual animals to create functional structures by joining together is rare and confined to the social insects. Army ants (Eciton) form collective assemblages out of their own bodies to perform a variety of functions that benefit the entire colony. Here we examine ‟bridges” of linked individuals that are constructed to span gaps in the colony’s foraging trail. How these living structures adjust themselves to varied and changing conditions remains poorly understood. Our field experiments show that the ants continuously modify their bridges, such that these structures lengthen, widen, and change position in response to traffic levels and environmental geometry. Ants initiate bridges where their path deviates from their incoming direction and move the bridges over time to create shortcuts over large gaps. The final position of the structure depended on the intensity of the traffic and the extent of path deviation and was influenced by a cost–benefit trade-off at the colony level, where the benefit of increased foraging trail efficiency was balanced by the cost of removing workers from the foraging pool to form the structure. To examine this trade-off, we quantified the geometric relationship between costs and benefits revealed by our experiments. We then constructed a model to determine the bridge location that maximized foraging rate, which qualitatively matched the observed movement of bridges. Our results highlight how animal self-assemblages can be dynamically modified in response to a group-level cost–benefit trade-off, without any individual unit’s having information on global benefits or costs. PMID:26598673

Breeding Better Forages to Help Feed Man and Preserve and Enhance the Environment

ERIC Educational Resources Information Center

Burton, Glenn W.

1973-01-01

Discusses the importance of forages in agriculture, and expresses the need for the same high level of technology that is used in the production of corn, wheat, and rice to be applied to forage production. Describes promising forage species, breeding objectives, and breeding procedures used in research. (JR)

A Unique Assemblage of Engraved Plaquettes from Ein Qashish South, Jezreel Valley, Israel: Figurative and Non-Figurative Symbols of Late Pleistocene Hunters-Gatherers in the Levant.

PubMed

Yaroshevich, Alla; Bar-Yosef, Ofer; Boaretto, Elisabeta; Caracuta, Valentina; Greenbaum, Noam; Porat, Naomi; Roskin, Joel

2016-01-01

Three engraved limestone plaquettes from the recently excavated Epipaleolithic open-air site Ein Qashish South in the Jezreel Valley, Israel comprise unique evidence for symbolic behavior of Late Pleistocene foragers in the Levant. The engravings, uncovered in Kebaran and Geometric Kebaran deposits (ca. 23ka and ca. 16.5ka BP), include the image of a bird-the first figurative representation known so far from a pre-Natufian Epipaleolithic-along with geometric motifs such as chevrons, crosshatchings and ladders. Some of the engravings closely resemble roughly contemporary European finds interpreted as "systems of notations" or "artificial memory systems"-records related to timing of seasonal resources and associated aggregation events of nomadic groups. Moreover, similarly looking signs and patterns are well known from the context of the local Natufian-a final Epipaleolithic culture of sedentary or semi-sedentary foragers who started practicing agriculture. The investigation of the engravings found in Ein Qashish South involves conceptualizations developed in studies of European and local parallels, a selection of ethnographic examples and preliminary microscopic observations of the plaquettes. This shows that the figurative and non-figurative images comprise a coherent assemblage of symbols that might have been applied in order to store, share and transmit information related to social and subsistence realms of mobile bands. It further suggests that the site functioned as a locality of groups' aggregation and indicates social complexity of pre-Natufian foragers in the Levant. While alterations in social and subsistence strategies can explain the varying frequency of image use characterizing different areas of the Late Pleistocene world-the apparent similarity in graphics and the mode of their application support the possibility that symbol-mediated behavior has a common and much earlier origin.

Intraspecific Variation among Social Insect Colonies: Persistent Regional and Colony-Level Differences in Fire Ant Foraging Behavior

PubMed Central

Bockoven, Alison A.; Wilder, Shawn M.; Eubanks, Micky D.

2015-01-01

Individuals vary within a species in many ecologically important ways, but the causes and consequences of such variation are often poorly understood. Foraging behavior is among the most profitable and risky activities in which organisms engage and is expected to be under strong selection. Among social insects there is evidence that within-colony variation in traits such as foraging behavior can increase colony fitness, but variation between colonies and the potential consequences of such variation are poorly documented. In this study, we tested natural populations of the red imported fire ant, Solenopsis invicta, for the existence of colony and regional variation in foraging behavior and tested the persistence of this variation over time and across foraging habitats. We also reared single-lineage colonies in standardized environments to explore the contribution of colony lineage. Fire ants from natural populations exhibited significant and persistent colony and regional-level variation in foraging behaviors such as extra-nest activity, exploration, and discovery of and recruitment to resources. Moreover, colony-level variation in extra-nest activity was significantly correlated with colony growth, suggesting that this variation has fitness consequences. Lineage of the colony had a significant effect on extra-nest activity and exploratory activity and explained approximately half of the variation observed in foraging behaviors, suggesting a heritable component to colony-level variation in behavior. PMID:26197456

Foraging performance of two fishes, the threespine stickleback and the Cumaná guppy, under different light backgrounds.

PubMed

Zukoshi, Reo; Savelli, Ilaria; Novales Flamarique, Iñigo

2018-04-01

Many vertebrates have cone photoreceptors that are most sensitive to ultraviolet (UV) light termed UV cones. The ecological functions that these cones contribute to are seldom known though they are suspected of improving foraging and communication in a variety of fishes. In this study, we used several spectral backgrounds to assess the contribution of UV and violet cones, or long wavelength (L) cones, in the foraging performance of juvenile Cumaná guppy, Poecilia reticulata, or marine stickleback, Gasterosteus aculeatus. Regardless of whether the light spectrum contained or not wavelengths below 450 nm (the limiting wavelength for UV cone stimulation), the foraging performance of both species was statistically the same, as judged by the mean distance and angle associated with attacks on prey (Daphnia magna). Our experiments also showed that the foraging performance of sticklebacks when only the double cones (and, almost exclusively, the L cones) were active was similar to that when all cones were functional, demonstrating that the double cone was sufficient for prey detection. This result indicates that foraging potentially relied on an achromatic channel serving prey motion detection, as the two spectral cone types that make up the double cone [maximally sensitive to middle (M) and long (L) wavelengths, respectively] form the input to the achromatic channel in cyprinid fishes and double cones are widely associated with achromatic tasks in other vertebrates including reptiles and birds. Stickleback performance was also substantially better when foraging under a 100% linearly polarized light field than when under an unpolarized light field. Together, our results suggest that in some teleost species UV cones exert visually-mediated ecological functions different from foraging, and furthermore that polarization sensitivity could improve the foraging performance of sticklebacks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of acidification on olfactory-mediated behaviour in freshwater and marine ecosystems: a synthesis

PubMed Central

Leduc, Antoine O. H. C.; Munday, Philip L.; Brown, Grant E.; Ferrari, Maud C. O.

2013-01-01

For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices. PMID:23980246

Effects of acidification on olfactory-mediated behaviour in freshwater and marine ecosystems: a synthesis.

PubMed

Leduc, Antoine O H C; Munday, Philip L; Brown, Grant E; Ferrari, Maud C O

2013-01-01

For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices.

Chronic exposure to a neonicotinoid pesticide alters the interactions between bumblebees and wild plants.

PubMed

Stanley, Dara A; Raine, Nigel E

2016-07-01

Insect pollinators are essential for both the production of a large proportion of world crops and the health of natural ecosystems. As important pollinators, bumblebees must learn to forage on flowers to feed both themselves and provision their colonies.Increased use of pesticides has caused concern over sublethal effects on bees, such as impacts on reproduction or learning ability. However, little is known about how sublethal exposure to field-realistic levels of pesticide might affect the ability of bees to visit and manipulate flowers.We observed the behaviour of individual bumblebees from colonies chronically exposed to a neonicotinoid pesticide (10 ppb thiamethoxam) or control solutions foraging for the first time on an array of morphologically complex wildflowers ( Lotus corniculatus and Trifolium repens ) in an outdoor flight arena.We found that more bees released from pesticide-treated colonies became foragers, and that they visited more L. corniculatus flowers than controls. Interestingly, bees exposed to pesticide collected pollen more often than controls, but control bees learnt to handle flowers efficiently after fewer learning visits than bees exposed to pesticide. There were also different initial floral preferences of our treatment groups; control bees visited a higher proportion of T. repens flowers, and bees exposed to pesticide were more likely to choose L. corniculatus on their first visit.Our results suggest that the foraging behaviour of bumblebees on real flowers can be altered by sublethal exposure to field-realistic levels of pesticide. This has implications for the foraging success and persistence of bumblebee colonies, but perhaps more importantly for the interactions between wild plants and flower-visiting insects and ability of bees to deliver the crucial pollination services to plants necessary for ecosystem functioning.

Evolution mediates the effects of apex predation on aquatic food webs

PubMed Central

Urban, Mark C.

2013-01-01

Ecological and evolutionary mechanisms are increasingly thought to shape local community dynamics. Here, I evaluate if the local adaptation of a meso-predator to an apex predator alters local food webs. The marbled salamander (Ambystoma opacum) is an apex predator that consumes both the spotted salamander (Ambystoma maculatum) and shared zooplankton prey. Common garden experiments reveal that spotted salamander populations which co-occur with marbled salamanders forage more intensely than those that face other predator species. These foraging differences, in turn, alter the diversity, abundance and composition of zooplankton communities in common garden experiments and natural ponds. Locally adapted spotted salamanders exacerbate prey biomass declines associated with apex predation, but dampen the top-down effects of apex predation on prey diversity. Countergradient selection on foraging explains why locally adapted spotted salamanders exacerbate prey biomass declines. The two salamander species prefer different prey species, which explains why adapted spotted salamanders buffer changes in prey composition owing to apex predation. Results suggest that local adaptation can strongly mediate effects from apex predation on local food webs. Community ecologists might often need to consider the evolutionary history of populations to understand local diversity patterns, food web dynamics, resource gradients and their responses to disturbance. PMID:23720548

Evolution mediates the effects of apex predation on aquatic food webs.

PubMed

Urban, Mark C

2013-07-22

Ecological and evolutionary mechanisms are increasingly thought to shape local community dynamics. Here, I evaluate if the local adaptation of a meso-predator to an apex predator alters local food webs. The marbled salamander (Ambystoma opacum) is an apex predator that consumes both the spotted salamander (Ambystoma maculatum) and shared zooplankton prey. Common garden experiments reveal that spotted salamander populations which co-occur with marbled salamanders forage more intensely than those that face other predator species. These foraging differences, in turn, alter the diversity, abundance and composition of zooplankton communities in common garden experiments and natural ponds. Locally adapted spotted salamanders exacerbate prey biomass declines associated with apex predation, but dampen the top-down effects of apex predation on prey diversity. Countergradient selection on foraging explains why locally adapted spotted salamanders exacerbate prey biomass declines. The two salamander species prefer different prey species, which explains why adapted spotted salamanders buffer changes in prey composition owing to apex predation. Results suggest that local adaptation can strongly mediate effects from apex predation on local food webs. Community ecologists might often need to consider the evolutionary history of populations to understand local diversity patterns, food web dynamics, resource gradients and their responses to disturbance.

Case study: dairies utilizing ultra-high stock density grazing in the Northeast

USDA-ARS?s Scientific Manuscript database

Ultra-high stock density (UHSD) grazing has gained interest in the forage industry. However, little credible research exists to support anecdotal claims that forage and soil improvement occur through trampling high proportions (75+%) of mature forage into the soil by grazing dense groups of cattle o...

Group-size-mediated habitat selection and group fusion-fission dynamics of bison under predation risk.

PubMed

Fortin, Daniel; Fortin, Marie-Eve; Beyer, Hawthorne L; Duchesne, Thierry; Courant, Sabrina; Dancose, Karine

2009-09-01

For gregarious animals the cost-benefit trade-offs that drive habitat selection may vary dynamically with group size, which plays an important role in foraging and predator avoidance strategies. We examined how habitat selection by bison (Bison bison) varied as a function of group size and interpreted these patterns by testing whether habitat selection was more strongly driven by the competing demands of forage intake vs. predator avoidance behavior. We developed an analytical framework that integrated group size into resource selection functions (RSFs). These group-size-dependent RSFs were based on a matched case-control design and were estimated using conditional logistic regression (mixed and population-averaged models). Fitting RSF models to bison revealed that bison groups responded to multiple aspects of landscape heterogeneity and that selection varied seasonally and as a function of group size. For example, roads were selected in summer, but not in winter. Bison groups avoided areas of high snow water equivalent in winter. They selected areas composed of a large proportion of meadow area within a 700-m radius, and within those areas, bison selected meadows. Importantly, the strength of selection for meadows varied as a function of group size, with stronger selection being observed in larger groups. Hence the bison-habitat relationship depended in part on the dynamics of group formation and division. Group formation was most likely in meadows. In contrast, risk of group fission increased when bison moved into the forest and was higher during the time of day when movements are generally longer and more variable among individuals. We also found that stronger selection for meadows by large rather than small bison groups was caused by longer residence time in individual meadows by larger groups and that departure from meadows appears unlikely to result from a depression in food intake rate. These group-size-dependent patterns were consistent with the hypothesis that avoidance of predation risk is the strongest driver of habitat selection.

Effects of dietary forage and calf starter on ruminal pH and transcriptomic adaptation of the rumen epithelium in Holstein calves during the weaning transition.

PubMed

Kim, Yo-Han; Toji, Noriyuki; Kizaki, Keiichiro; Kushibiki, Shiro; Ichijo, Toshihiro; Sato, Shigeru

2016-11-01

We investigated the relationship between ruminal pH and transcriptomic adaptation of the rumen epithelium (RE) of calves fed calf starter with and without forage during the weaning transition. Holstein calves were assigned to groups fed calf starter either with forage (HAY group, n = 3) or without forage (CON group, n = 4). Ruminal pH was measured continuously, and rumen fluid and epithelium were collected 3 wk after weaning. mRNA expression profiles of the RE were examined by one-color microarray. Differentially expressed genes (DEGs) were investigated using the Ingenuity Pathway Analysis (IPA). Mean and maximum ruminal pH were significantly (P < 0.05) higher, and the duration of pH < 5.8 during 1 day was significantly (P < 0.05) shorter, in the HAY group. The proportion of ruminal acetate and the acetate-to-propionate ratio were significantly (P < 0.05) lower in the CON group. DEGs encoding transcription regulators (SREBP1), insulin-like growth factor binding proteins (IGFBP7 and CTGF), ketogenic enzymes (HMGCL, BDH1, and BDH2), and a transporter (SLC16A3) were identified (P < 0.05) between the two groups. A growth factor (TGFB1) and signaling pathway (EGF and EGFR) were activated as upstream regulators. These results suggest that dietary forage alleviates ruminal acidosis, and the decrease in ruminal pH may damage the RE, leading to changes in gene expression to repair the damage. Furthermore, rumen development may be regulated by growth factor (TGFB1) and signaling pathways (EGF and IGFBP) for adaptation to feeding on calf starter with and without forage during the weaning transition. Copyright © 2016 the American Physiological Society.

Effects of environmental complexity and temporary captivity on foraging behavior of wild-caught meadow voles.

PubMed

Kozuch, Amaranta E; McPhee, M Elsbeth

2014-01-01

Increased housing of wild nonhuman animals in captivity for conservation, research, and rehabilitation has revealed the importance of systematically analyzing effects of the captive environment on behavior. This study focused on the effects of complexity and time held in captivity on foraging behaviors of wild-caught, adult meadow voles (Microtus pennsylvanicus). Forty-six individuals captured from a meadow outside Oshkosh, WI, were assigned to 1 of 4 captive treatment groups: simple/<50 days (SS), simple/>50 days, complex/<50 days, and complex/>50 days. Number of dish visits, proportion foraging, and frequency of nonforaging behaviors recorded during a 15-min foraging trial were measured for all subjects. Kruskal-Wallis and Mann-Whitney U Tests were conducted to analyze 4 different comparisons within this behavioral data. Overall, neither time in captivity or environmental complexity affected nonforaging behaviors. In contrast, foraging behaviors did change with treatment: Voles were less active at food dishes and visited control dishes more in treatment group SS than in the other treatment groups. In addition, sex-related differences in foraging behaviors were maintained when voles were exposed to environmental complexity. This article includes options for wildlife managers to adapt captive environments to meet the welfare and behavioral needs of translocated wild nonhuman mammals.

Gene-Silencing-Induced Changes in Carbohydrate Conformation in Relation to Bioenergy Value and Carbohydrate Subfractions in Modeled Plant (Medicago sativa) with Down-Regulation of HB12 and TT8 Transcription Factors

PubMed Central

Li, Xinxin; Hannoufa, Abdelali; Zhang, Yonggen; Yu, Peiqiang

2016-01-01

Gene silencing with RNA interference (RNAi) technology may be capable of modifying internal structure at a molecular level. This structural modification could affect biofunctions in terms of biodegradation, biochemical metabolism, and bioactive compound availability. The objectives of this study were to (1) Detect gene silencing-induced changes in carbohydrate molecular structure in an alfalfa forage (Medicago sativa spp. sativa: alfalfa) with down-regulation of genes that encode transcription factors TT8 and HB12; (2) Determine gene silencing-induced changes in nutrient bioutilization and bioavailability in the alfalfa forage (Medicago sativa); and (3) Quantify the correlation between gene silencing-induced molecular structure changes and the nutrient bioutilization and bioavailability in animals of ruminants. The experimental treatments included: T1 = Non-transgenic and no-gene silenced alfalfa forage (code “NT”); T2 = HB12-RNAi forage with HB12 gene down regulation (code “HB12”); T3 = TT8-RNAi forage with TT8 gene down regulation (code “TT8”). The HB12 and TT8 gene silencing-induced molecular structure changes were determined by non-invasive and non-destructive advanced molecular spectroscopy in a middle infrared radiation region that focused on structural, non-structural and total carbohydrate compounds. The nutrient bioutilization and bioavailability of the modified forage were determined using NRC-2001 system in terms of total digestive nutrient (TDN), truly digestible fiber (tdNDF), non-fiber carbohydrate (tdNDF), fatty acid (tdFA), crude protein (tdCP) and bioenergy profiles (digestible energy, metabolizable energy, net energy) for ruminants. The carbohydrate subfractions were evaluated using the updated CNCPS 6.0 system. The results showed that gene silencing significantly affected tdNFC (42.3 (NT) vs. 38.7 (HB12) vs. 37.4% Dry Matter (TT8); p = 0.016) and tdCP (20.8 (NT) vs. 19.4 (HB12) vs. 22.3% DM (TT8); p = 0.009). The gene-silencing also affected carbohydrate CA4 (7.4 (NT) vs. 4.2 (HB12) and 4.4% carbohydrate (CHO) (TT8), p = 0.063) and CB1 fractions (5.3 (NT) vs. 2.0 (HB12) and 2.6% CHO (TT8), p = 0.006). The correlation study showed that the structural CHO functional group peak area intensity at ca. 1315 cm−1 was significantly correlated to the TDN1x (r = −0.83, p = 0.042) and the tdNFC (r = −0.83, p = 0.042), the structural CHO functional group height intensity at ca. 1370 cm−1 was significantly correlated to the tdNDF (r = −0.87, p = 0.025). The A_Non-stCHO to A_StCHO ratio and A_Non-stCHO to A_CHO ratio were significantly correlated to the tdFA (r = 0.83–0.91, p < 0.05). As to carbohydrate fractions, both CA4 and CB1 correlated with carbohydrate spectral intensity of the H_1415 and the H_1315 (p = 0.039; p = 0.059, respectively), CB3 tended to correlate with the H_1150, H_1100 and H_1025 (p < 0.10). In conclusion, RNAi-mediated silencing of HB12 and TT8 modified not only inherent CHO molecular structure but also the biofunctions. The CHO molecular structure changes induced by RNAi gene silencing were associated with biofunctions in terms of the carbohydrate subfractions and nutrient digestion. PMID:27187372

Gene-Silencing-Induced Changes in Carbohydrate Conformation in Relation to Bioenergy Value and Carbohydrate Subfractions in Modeled Plant (Medicago sativa) with Down-Regulation of HB12 and TT8 Transcription Factors.

PubMed

Li, Xinxin; Hannoufa, Abdelali; Zhang, Yonggen; Yu, Peiqiang

2016-05-13

Gene silencing with RNA interference (RNAi) technology may be capable of modifying internal structure at a molecular level. This structural modification could affect biofunctions in terms of biodegradation, biochemical metabolism, and bioactive compound availability. The objectives of this study were to (1) Detect gene silencing-induced changes in carbohydrate molecular structure in an alfalfa forage (Medicago sativa spp. sativa: alfalfa) with down-regulation of genes that encode transcription factors TT8 and HB12; (2) Determine gene silencing-induced changes in nutrient bioutilization and bioavailability in the alfalfa forage (Medicago sativa); and (3) Quantify the correlation between gene silencing-induced molecular structure changes and the nutrient bioutilization and bioavailability in animals of ruminants. The experimental treatments included: T1 = Non-transgenic and no-gene silenced alfalfa forage (code "NT"); T2 = HB12-RNAi forage with HB12 gene down regulation (code "HB12"); T3 = TT8-RNAi forage with TT8 gene down regulation (code "TT8"). The HB12 and TT8 gene silencing-induced molecular structure changes were determined by non-invasive and non-destructive advanced molecular spectroscopy in a middle infrared radiation region that focused on structural, non-structural and total carbohydrate compounds. The nutrient bioutilization and bioavailability of the modified forage were determined using NRC-2001 system in terms of total digestive nutrient (TDN), truly digestible fiber (tdNDF), non-fiber carbohydrate (tdNDF), fatty acid (tdFA), crude protein (tdCP) and bioenergy profiles (digestible energy, metabolizable energy, net energy) for ruminants. The carbohydrate subfractions were evaluated using the updated CNCPS 6.0 system. The results showed that gene silencing significantly affected tdNFC (42.3 (NT) vs. 38.7 (HB12) vs. 37.4% Dry Matter (TT8); p = 0.016) and tdCP (20.8 (NT) vs. 19.4 (HB12) vs. 22.3% DM (TT8); p = 0.009). The gene-silencing also affected carbohydrate CA4 (7.4 (NT) vs. 4.2 (HB12) and 4.4% carbohydrate (CHO) (TT8), p = 0.063) and CB1 fractions (5.3 (NT) vs. 2.0 (HB12) and 2.6% CHO (TT8), p = 0.006). The correlation study showed that the structural CHO functional group peak area intensity at ca. 1315 cm(-1) was significantly correlated to the TDN1x (r = -0.83, p = 0.042) and the tdNFC (r = -0.83, p = 0.042), the structural CHO functional group height intensity at ca. 1370 cm(-1) was significantly correlated to the tdNDF (r = -0.87, p = 0.025). The A_Non-stCHO to A_StCHO ratio and A_Non-stCHO to A_CHO ratio were significantly correlated to the tdFA (r = 0.83-0.91, p < 0.05). As to carbohydrate fractions, both CA4 and CB1 correlated with carbohydrate spectral intensity of the H_1415 and the H_1315 (p = 0.039; p = 0.059, respectively), CB3 tended to correlate with the H_1150, H_1100 and H_1025 (p < 0.10). In conclusion, RNAi-mediated silencing of HB12 and TT8 modified not only inherent CHO molecular structure but also the biofunctions. The CHO molecular structure changes induced by RNAi gene silencing were associated with biofunctions in terms of the carbohydrate subfractions and nutrient digestion.

The Dynamics of Foraging Trails in the Tropical Arboreal Ant Cephalotes goniodontus

PubMed Central

Gordon, Deborah M.

2012-01-01

The foraging behavior of the arboreal turtle ant, Cephalotes goniodontus, was studied in the tropical dry forest of western Mexico. The ants collected mostly plant-derived food, including nectar and fluids collected from the edges of wounds on leaves, as well as caterpillar frass and lichen. Foraging trails are on small pieces of ephemeral vegetation, and persist in exactly the same place for 4–8 days, indicating that food sources may be used until they are depleted. The species is polydomous, occupying many nests which are abandoned cavities or ends of broken branches in dead wood. Foraging trails extend from trees with nests to trees with food sources. Observations of marked individuals show that each trail is travelled by a distinct group of foragers. This makes the entire foraging circuit more resilient if a path becomes impassable, since foraging in one trail can continue while a different group of ants forms a new trail. The colony’s trails move around the forest from month to month; from one year to the next, only one colony out of five was found in the same location. There is continual searching in the vicinity of trails: ants recruited to bait within 3 bifurcations of a main foraging trail within 4 hours. When bait was offered on one trail, to which ants recruited, foraging activity increased on a different trail, with no bait, connected to the same nest. This suggests that the allocation of foragers to different trails is regulated by interactions at the nest. PMID:23209749

Foraging Allocation in the Honey Bee, Apis mellifera L. (Hymenoptera, Apidae), Tuned by the Presence of the Spinosad-Based Pesticide GF-120.

PubMed

Cabrera-Marín, N V; Liedo, P; Vandame, R; Sánchez, D

2015-04-01

Agroecosystem management commonly involves the use of pesticides. As a result, a heterogeneous landscape is created, in which suitable and unsuitable spaces are defined by the absence/presence of pesticides. In this study, we explored how foragers of the honey bee, Apis mellifera L., adapt to such context. We specifically evaluated the effect of GF-120, a spinosad-based fruit fly toxic bait, on the allocation of foragers between food sources under the hypothesis that foragers will move from food sources with GF-120 to food sources without it. We thus carried out three experiments: in experiment 1, a group of foragers was trained to collect honey solution from a feeder; next, this feeder offered a GF-120/honey solution. A minority of foragers continued collecting the GF-120/honey solution. In experiment 2, we trained two groups of foragers from a colony to two food sources equally rewarding. Next, GF-120 was added to one of the food sources. We found that the majority of foragers moved from the GF-120-treated feeder to the feeder without GF-120 and that the minority that continued visiting the GF-120-treated feeder did not collect the GF-120/honey solution. In a third experiment, we wanted to know if foragers in an experimental setup as in experiment 1 would perform waggle dances: none of the foragers that collected GF-120/honey were observed dancing. Our results emphasize the importance of "food refuges" for non-target species, since they minimize the impact of agrochemicals upon them.

Stable Isotopic Insights into the Foraging Ecology of an Endangered Marine Predator, the Hawaiian Petrel

NASA Astrophysics Data System (ADS)

Wiley, A. E.; Ostrom, P. H.; James, H. F.

2010-12-01

Seabirds play vital roles in their ecosystems, both as predators in their oceanic foraging grounds and conduits of marine nutrients to island nesting sites. Despite growing evidence that food availability limits seabird populations, characterization of the diet and even foraging locations of some seabird species remains elusive. Here, we use stable carbon (δ13C) and nitrogen (δ15N) isotopes to study the foraging ecology of an endangered and poorly known seabird, the Hawaiian petrel (Pterodroma sandwichensis). This species nests solely on the main Hawaiian Islands but forages widely across the NE Pacific, sometimes traveling over 10,000km on single foraging trips. δ13C and δ15N values vary with trophic level and at the base of food webs throughout the marine range of the Hawaiian petrel. Thus, we are able to use isotope signatures in modern and ancient petrel tissues to track spatial and temporal variation in foraging location and diet. We find strong evidence of foraging segregation between populations, with hatch-year birds from the island of Hawaii exhibiting feather δ15N and δ13C values over 3‰ and 1 ‰ higher, respectively, than those found in Maui and Kauai hatch-year birds. There is also significant variation in δ15N values between feathers from Kauai, Hawaii, and Maui adults, indicating additional foraging segregation during the winter molt. To distinguish between the effects of trophic level and foraging location, we relate our data to those from seabirds with known diet and foraging location, as well as to previous characterizations of isoscapes in the NE Pacific and at-sea observations of our study species. Finally, we track Hawaiian petrel foraging ecology back in time through examination of stable isotope values in historical feathers and ancient bone collagen. We find that, despite a species-wide decline in δ15N values (consistent with trophic level decline), populations have maintained divergent isotopic niches through at least the past 1,000 years. These data offer rare insight into the long-term fluxuations of seabird foraging habits as well as important information for the conservation of Hawaiian petrels and ultimately, the ecosystems they inhabit.

The effects of chlorpyrifos on cholinesterase activity and foraging behavior in the dragonfly, Anax junius (Odonata)

USGS Publications Warehouse

Brewer, S.K.; Atchison, G.J.

1999-01-01

We examined head capsule cholinesterase (ChE) and foraging behavior in nymphs of the dragonfly, Anax junius, exposed for 24 h to 0.2, 0.6 and 1.0 ??g l-1 of the organophosphorus (OP) insecticide, chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate]. The invertebrate community is an important component of the structure and function of wetland ecosystems, yet the potential effects of insecticides on wetland ecosystems are largely unknown. Our objectives were to determine if exposure to environmentally realistic concentrations of chlorpyrifos affected foraging behavior and ChE activity in head capsules of dragonfly nymphs. Nymphs were exposed to different concentrations of chlorpyrifos and different prey densities in a factorial design. ChE activities and foraging behaviors of treated nymphs were not statistically different (p ??? 0.05) from control groups. Prey density effects exerted a greater effect on dragonfly foraging than toxicant exposures. Nymphs offered higher prey densities exhibited more foraging behaviors but also missed their prey more often. High variability in ChE activities within the control group and across treated groups precluded determination of relationships between ChE and foraging behaviors. It appears that A. junius is relatively tolerant of chlorpyrifos, although the concentrations we tested have been shown in other work to adversely affect the prey base; therefore the introduction of this insecticide may have indirect adverse affects on top invertebrate predators such as Odonata.

Relative importance of social factors, conspecific density, and forest structure on space use by the endangered Red-cockaded Woodpecker: A new consideration for habitat restoration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garabedian, James E.; Moorman, Christopher E.; Peterson, M. Nils

Understanding how the interplay between social behaviors and habitat structure influences space use is important for conservation of birds in restored habitat. We integrated fine-grained LiDAR-derived habitat data, spatial distribution of cavity trees, and spatially explicit behavioral observations in a multi-scale model to determine the relative importance of conspecific density, intraspecific interactions, and the distribution of cavities on space use by Red-cockaded Woodpeckers (Picoides borealis) on 2 sites in South Carolina, USA. We evaluated candidate models using information theoretic methods. Top scale-specific models included effects of conspecific density and number of cavity tree starts within 200 m of Red-cockaded Woodpeckermore » foraging locations, and effects of the number of intraspecific interactions within 400 m of Red-cockaded Woodpecker foraging locations. The top multi-scale model for 22 of 34 Red-cockaded Woodpecker groups included covariates for the number of groups within 200 m of foraging locations and LiDARderived habitat with moderate densities of large pines (Pinus spp.) and minimal hardwood overstory. These results indicate distribution of neighboring groups was the most important predictor of space use once a minimal set of structural habitat thresholds was reached, and that placing recruitment clusters as little as 400 m from foraging partitions of neighboring groups may promote establishment of new breeding groups in unoccupied habitat. The presence of neighboring groups likely provides cues to foraging Red-cockaded Woodpeckers that facilitate prospecting prior to juvenile dispersal and, to a lesser extent, indicates high-quality forage resources. Careful consideration of local distribution of neighboring groups in potential habitat may improve managers’ ability to increase Red-cockaded Woodpecker density on restored landscapes and mitigate isolation of Red-cockaded Woodpecker groups, a problem that negatively affects fitness across the species’ range.« less

Foraging recruitment by the Giant Tropical Ant Paraponera clavata (Hymenoptera, Formicidae)

USGS Publications Warehouse

Barrett, Bruce A.; Jorgenson, Clive D.; Looman, Sandra J.

1985-01-01

Increased foraging of an exceptionally abundant, but ephemeral, food source by ants can result from foraging excitement that does not include pheromone trails, tandem running, or from recruitment of other workers along pheromone trails (Carrol and Janzen, 1973). They also provided rationale for two types of short-lived pheromone trails resulting in mass or group recruitment. These both seem to fall into the Type II foraging strategy described by Oster and Wilson (1978). Neither of these discussions conveniently allow for pheromone recruitment by relatively small colonies of a primitive monomorphic species such as Paraponera clavata. Our observations suggest that recruitment to an abundant ephemeral food source does occur naturally and can be induced artificially in colonies of P. clavata.Paraponera clavata is considered primitive (Wilson, 1958), particularly in foraging habits (Young and Hermann, 1980; Young, 1977). Hermann (1973, 1975) reported the P. clavata, unlike more advanced species, forages independently; following shot periods of apparent group activity outside of the colony (Young and Hermann, 1980). It reportedly does not return to a food source when only part has been harvested. After returning to its colony with booty, a single worker resumes foraging independently, with no observable tendency to return to partially harvested booty or without recruiting additional workers to collect the remaining food (Hermann, 1973; Young and Hermann, 1980). Reports of independent foraging, lack of forager recruitment, and apparent lack of food source fidelity resulted in the assumption that P. clavata probably lacks an effective pheromone trail communication system (Young and Hermann, 1980).

Studying sea otter foraging ecology: A review of some methodological approaches

USGS Publications Warehouse

Tinker, M.T.; Estes, J.A.; Bodkin, James L.; Staedler, M.M.; Monson, Daniel H.; Maldini, Daniela; Calkins, Donald; Atkinson, Shannon; Meehan, Rosa

2004-01-01

The study of foraging ecology plays a central role in our understanding of animal populations and natural communities, and can also provide information necessary for the effective conservation of rare or endangered species. Sea otter researchers are interested in foraging ecology for many different reasons, but for heuristic purposes we identify three general types of research questions: (1) questions about the implications of foraging decisions to individual fitness, the evolutionary significance of feeding strategies, and the selective forces and constraints that shape an individual’s diet and feeding behavior; (2) questions about the population- level implications of foraging ecology; for example, how is the status of a population (with respect to carrying capacity) reflected by the foraging success or diet composition of individuals within the population (Fig. 1); and (3) questions about the community-level consequences of sea otter foraging. Sea otters provide an excellent study system for all three types of questions because they are a tractable species to study (generally feeding near shore and bringing all prey to the surface to consume), they exhibit a wide range of diets and foraging strategies in different habitats and at different population densities, they tend to have strong trophic interactions with their prey species, and their foraging behavior can have profound effects on community structure in the nearshore marine community.

Analysis of lead concentration in forager stingless bees Trigona sp. (hymenoptera: Apidae) and propolis at Cilutung and Maribaya, West Java

NASA Astrophysics Data System (ADS)

Safira, Nabila; Anggraeni, Tjandra

2015-09-01

Several studies had shown that lead (Pb) in the environment could accumulate in bees, which in turn could affect the quality of the resulting product. In this study, forager stingless bees (Trigona sp.) and its product (propolis) collected from a stingless bees apiculture. This apiculture had two apiary sites which were distinguished by its environmental setting. Apiary site in Cilutung had a forest region environmental setting, while apiary site in Maribaya was located beside the main road. The objective of this study was to determine the extent of lead concentration in propolis originated from both apiary sites and establish the correlation between lead concentration in propolis and lead level in forager stingless bees. Forager bees and propolis samples were originated from 50 bees colonies (Cilutung) and 44 bees colonies (Maribaya). They were analyzed using AAS-GF (Atomic Absorption Spectrometre-Graphite Furnace) to determine the level of lead concentration. The results showed that the average level of lead in propolis originated from Cilutung (298.08±73.71 ppb) was lower than the average level of lead in forager bees which originated from Maribaya (330.64±156.34 ppb). However, these values did not show significant difference (p>0.05). There was no significant difference (p>0.05) between the average level of lead in forager bees which originated from Cilutung (118.08±30.46 ppb) and Maribaya (128.82±39.66 ppb). However, these values did not show significant difference (p>0.05). In conclusion, the average level of lead concentration in propolis in both sites had passed the maximum permission standard of lead for food in Indonesia. There was no correlation between lead concentration in propolis and forager stingless bees.

Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season

PubMed Central

Murillo, M.; Herrera, E.; Ruiz, O.; Reyes, O.; Carrete, F. O.; Gutierrez, H.

2016-01-01

Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with increasing levels of CDDGS supplementation (p<0.05). However, acetate concentrations decreased with increasing levels of CDDGS supplementation (p<0.05). Liquid dilution rate increased with increasing levels of CDDGS supplementation but ruminal liquid volume decreased (p<0.05). On the basis of these findings, we can conclude that CDDGS supplementation enhanced the productive performance of cattle grazing native rangeland without negatively affecting forage intake, glucose and urea-nitrogen blood concentrations, ruminal degradation and ruminal fermentation patterns. PMID:26954168

Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season.

PubMed

Murillo, M; Herrera, E; Ruiz, O; Reyes, O; Carrete, F O; Gutierrez, H

2016-05-01

Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with increasing levels of CDDGS supplementation (p<0.05). However, acetate concentrations decreased with increasing levels of CDDGS supplementation (p<0.05). Liquid dilution rate increased with increasing levels of CDDGS supplementation but ruminal liquid volume decreased (p<0.05). On the basis of these findings, we can conclude that CDDGS supplementation enhanced the productive performance of cattle grazing native rangeland without negatively affecting forage intake, glucose and urea-nitrogen blood concentrations, ruminal degradation and ruminal fermentation patterns.

Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins

NASA Astrophysics Data System (ADS)

Ji, Cuiying; Zhang, Xuewei; Yu, Peiqiang

2016-03-01

The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653 cm- 1 and 1545 cm- 1, respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties.

Plant guide: Nineleaf biscuitroot (Lomatium triternatum)

Treesearch

Derek Tilley; Loren St. John; Dan Ogle; Nancy Shaw

2010-01-01

Nineleaf biscuitroot begins growth very early in the spring, often just following snow melt, providing crucial early forage for many wildlife and domestic animals. It is considered one of the most valuable forage species of the genus due to its large stature and high production levels. It is rated as having fair to very good forage for sheep and poor to good forage for...

State of emergency: behavior of gerbils is affected by the hunger state of their predators.

PubMed

Berger-Tal, Oded; Kotler, Burt P

2010-02-01

Predator-prey interactions are usually composed of behaviorally sophisticated games in which the values of the strategies of foraging prey individuals may depend on those of their predators, and vice versa. Therefore, any change in the behavior of the predator should result in changes to the behavior of the prey. However, this key prediction has rarely been tested. To examine the effects of the predator state on prey behavior, we manipulated the state of captive Barn Owls, Tyto alba, and released them into an enclosure containing Allenby's gerbils, Gerbillus andersoni allenbyi, a common prey of the owls. The owls were significantly more active when hungry. In response, the gerbils altered their behavior according to the state of the owl. When the owl was hungry, the gerbils visited fewer food patches, foraged in fewer patches, and harvested less food from each patch. Moreover, the gerbils kept their foraging bouts closer to their burrow, which reduced the overlap among foraging ranges of individual gerbils. Thus, changes in the state of the predator affect the foraging behavior of its prey and can also mediate competition among prey individuals.

Habitat use by female caribou: Tradeoffs associated with parturition

USGS Publications Warehouse

Barten, Neil L.; Bowyer, R.T.; Jenkins, Kurt J.

2001-01-01

We compared habitat use, forage characteristics, and group size among preparturient, parturient, and nonparturient female caribou (Rangifer tarandus) during and after the birthing season to test hypotheses involving acquisition of forage and risk of predation. We monitored 39 radiocollared females from the Mentasta caribou herd, Alaska, in 1994 and 40 animals in 1995. Group size of females giving birth at higher elevations was smaller (P 0.5). During peak parturition, females with young used sites with fewer predators (P < 0.05), a lower abundance of forage (P < 0.05), but with variable forage quality compared with those sites used by females without young. We hypothesized that parturient females used birth sites that lowered risk of predation, and traded-off forage abundance for increased safety. Nonetheless, few differences existed between parturient and nonparturient females in composition of diet or in indices of diet quality; we could not demonstrate a nutritional cost to maternal females from our analyses. We suggest that increasing population density might intensify intraspecific competition among females for birth sites, and thereby increase nutritional costs of using high-elevation areas with less forage but fewer predators.

Comparison of laboratory and field remote sensing methods to measure forage quality.

PubMed

Guo, Xulin; Wilmshurst, John F; Li, Zhaoqin

2010-09-01

Recent research in range ecology has emphasized the importance of forage quality as a key indicator of rangeland condition. However, we lack tools to evaluate forage quality at scales appropriate for management. Using canopy reflectance data to measure forage quality has been conducted at both laboratory and field levels separately, but little work has been conducted to evaluate these methods simultaneously. The objective of this study is to find a reliable way of assessing grassland quality through measuring forage chemistry with reflectance. We studied a mixed grass ecosystem in Grasslands National Park of Canada and surrounding pastures, located in southern Saskatchewan. Spectral reflectance was collected at both in-situ field level and in the laboratory. Vegetation samples were collected at each site, sorted into the green grass portion, and then sent to a chemical company for measuring forage quality variables, including protein, lignin, ash, moisture at 135 °C, Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Total Digestible, Digestible Energy, Net Energy for Lactation, Net Energy for Maintenance, and Net Energy for Gain. Reflectance data were processed with the first derivative transformation and continuum removal method. Correlation analysis was conducted on spectral and forage quality variables. A regression model was further built to investigate the possibility of using canopy spectral measurements to predict the grassland quality. Results indicated that field level prediction of protein of mixed grass species was possible (r² = 0.63). However, the relationship between canopy reflectance and the other forage quality variables was not strong.

A global comparison of the nutritive values of forage plants grown in contrasting environments.

PubMed

Lee, Mark A

2018-03-17

Forage plants are valuable because they maintain wild and domesticated herbivores, and sustain the delivery of meat, milk and other commodities. Forage plants contain different quantities of fibre, lignin, minerals and protein, and vary in the proportion of their tissue that can be digested by herbivores. These nutritive components are important determinants of consumer growth rates, reproductive success and behaviour. A dataset was compiled to quantify variation in forage plant nutritive values within- and between-plant species, and to assess variation between plant functional groups and bioclimatic zones. 1255 geo-located records containing 3774 measurements of nutritive values for 136 forage plant species grown in 30 countries were obtained from published articles. Spatial variability in forage nutritive values indicated that climate modified plant nutritive values. Forage plants grown in arid and equatorial regions generally contained less digestible material than those grown in temperate and tundra regions; containing more fibre and lignin, and less protein. These patterns may reveal why herbivore body sizes, digestion and migration strategies are different in warmer and drier regions. This dataset also revealed the capacity for variation in the nutrition provided by forage plants, which may drive consumer species coexistence. The proportion of the plant tissue that was digestible ranged between species from 2 to 91%. The amount of fibre contained within plant material ranged by 23-90%, protein by 2-36%, lignin by 1-21% and minerals by 2-22%. On average, grasses and tree foliage contained the most fibre, whilst herbaceous legumes contained the most protein and tree foliage contained the most lignin. However, there were individual species within each functional group that were highly nutritious. This dataset may be used to identify forage plant species or mixtures of species from different functional groups with useful nutritional traits which can be cultivated to enhance livestock productivity and inform wild herbivore conservation strategies.

The Impact of Detoxification Costs and Predation Risk on Foraging: Implications for Mimicry Dynamics

PubMed Central

Skelhorn, John; Rowe, Candy; Ruxton, Graeme D.; Higginson, Andrew D.

2017-01-01

Prey often evolve defences to deter predators, such as noxious chemicals including toxins. Toxic species often advertise their defence to potential predators by distinctive sensory signals. Predators learn to associate toxicity with the signals of these so-called aposematic prey, and may avoid them in future. In turn, this selects for mildly toxic prey to mimic the appearance of more toxic prey. Empirical evidence shows that mimicry could be either beneficial (‘Mullerian’) or detrimental (‘quasi-Batesian’) to the highly toxic prey, but the factors determining which are unknown. Here, we use state-dependent models to explore how tri-trophic interactions could influence the evolution of prey defences. We consider how predation risk affects predators’ optimal foraging strategies on aposematic prey, and explore the resultant impact this has on mimicry dynamics between unequally defended species. In addition, we also investigate how the potential energetic cost of metabolising a toxin can alter the benefits to eating toxic prey and thus impact on predators’ foraging decisions. Our model predicts that both how predators perceive their own predation risk, and the cost of detoxification, can have significant, sometimes counterintuitive, effects on the foraging decisions of predators. For example, in some conditions predators should: (i) avoid prey they know to be undefended, (ii) eat more mildly toxic prey as detoxification costs increase, (iii) increase their intake of highly toxic prey as the abundance of undefended prey increases. These effects mean that the relationship between a mimic and its model can qualitatively depend on the density of alternative prey and the cost of metabolising toxins. In addition, these effects are mediated by the predators’ own predation risk, which demonstrates that, higher trophic levels than previously considered can have fundamental impacts on interactions among aposematic prey species. PMID:28045959

Group cohesion in foraging meerkats: follow the moving 'vocal hot spot'.

PubMed

Gall, Gabriella E C; Manser, Marta B

2017-04-01

Group coordination, when 'on the move' or when visibility is low, is a challenge faced by many social living animals. While some animals manage to maintain cohesion solely through visual contact, the mechanism of group cohesion through other modes of communication, a necessity when visual contact is reduced, is not yet understood. Meerkats ( Suricata suricatta ), a small, social carnivore, forage as a cohesive group while moving continuously. While foraging, they frequently emit 'close calls', soft close-range contact calls. Variations in their call rates based on their local environment, coupled with individual movement, produce a dynamic acoustic landscape with a moving 'vocal hotspot' of the highest calling activity. We investigated whether meerkats follow such a vocal hotspot by playing back close calls of multiple individuals to foraging meerkats from the front and back edge of the group simultaneously. These two artificially induced vocal hotspots caused the group to spatially elongate and split into two subgroups. We conclude that meerkats use the emergent dynamic call pattern of the group to adjust their movement direction and maintain cohesion. Our study describes a highly flexible mechanism for the maintenance of group cohesion through vocal communication, for mobile species in habitats with low visibility and where movement decisions need to be adjusted continuously to changing environmental conditions.

Associations between male testosterone and immune function in a pathogenically stressed forager-horticultural population

PubMed Central

Trumble, Benjamin C; Blackwell, Aaron D; Stieglitz, Jonathan; Thompson, Melissa Emery; Suarez, Ivan Maldonado; Kaplan, Hillard; Gurven, Michael

2016-01-01

Objectives Despite well-known fitness advantages to males who produce and maintain high endogenous testosterone levels, such phenotypes may be costly if testosterone-mediated investment in reproductive effort trade-off against investment in somatic maintenance. Previous studies of androgen-mediated trade-offs in human immune function find mixed results, in part because most studies either focus on a few indicators of immunity, are confounded by phenotypic correlation, or are observational. Here the association between male endogenous testosterone and 13 circulating cytokines are examined before and after ex vivo antigen stimulation with phytohaemagglutinin (PHA) and lipopolysaccharides (LPS) in a high pathogen population of Bolivian forager-horticulturalists. Materials and Methods A Milliplex 13-plex cytokine panel measured cytokine concentration in whole blood samples from 109 Tsimane men aged 40–89 (median=50 years) before and after antigen stimulation with PHA and LPS. Urinary testosterone was measured via enzyme immunoassay; demographic and anthropometric data were collected as part of the Tsimane Health and Life History Project. Results Higher endogenous testosterone was associated with down-regulated responses in all cytokines after PHA stimulation (but significantly in only 2/13 cytokines), controlling for age and body mass index. In contrast, testosterone was not significantly associated with down-regulation of cytokines after LPS stimulation. MANOVAs indicate that men with higher testosterone showed reduced cytokine responses to PHA compared to LPS (p=0.0098). Discussion Endogenous testosterone appears to be immunomodulatory rather than immunosuppressive. Potentially costlier forms of immune activation like those induced by PHA (largely T-cell biased immune activation) are down-regulated in men with higher testosterone, but testosterone has less impact on potentially less costly immune activation following LPS stimulation (largely B-cell mediated immunity). PMID:27465811

A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation.

PubMed

Brasso, Rebecka L; Chiaradia, André; Polito, Michael J; Raya Rey, Andrea; Emslie, Steven D

2015-08-15

The wide geographic distribution of penguins (Order Sphenisciformes) throughout the Southern Hemisphere provided a unique opportunity to use a single taxonomic group as biomonitors of mercury among geographically distinct marine ecosystems. Mercury concentrations were compared among ten species of penguins representing 26 geographically distinct breeding populations. Mercury concentrations were relatively low (⩽2.00ppm) in feathers from 18/26 populations considered. Population-level differences in trophic level explained variation in mercury concentrations among Little, King, and Gentoo penguin populations. However, Southern Rockhopper and Magellanic penguins breeding on Staten Island, Tierra del Fuego, had the highest mercury concentrations relative to their conspecifics despite foraging at a lower trophic level. The concurrent use of stable isotope and mercury data allowed us to document penguin populations at the greatest risk of exposure to harmful concentrations of mercury as a result of foraging at a high trophic level or in geographic 'hot spots' of mercury availability. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 180.370 - 5-Ethoxy-3-(trichloromethyl)-1,2,4-thiadiazole; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., seed 0.1 Sorghum, grain, forage 0.1 Sorghum, grain, grain 0.1 Tomato 0.15 Vegetable, foliage of legume, group 7 0.1 Vegetable, legume, group 6 0.1 Wheat, forage 0.1 Wheat, grain 0.1 Wheat, straw 0.1 (b...

40 CFR 180.370 - 5-Ethoxy-3-(trichloromethyl)-1,2,4-thiadiazole; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., seed 0.1 Sorghum, grain, forage 0.1 Sorghum, grain, grain 0.1 Tomato 0.15 Vegetable, foliage of legume, group 7 0.1 Vegetable, legume, group 6 0.1 Wheat, forage 0.1 Wheat, grain 0.1 Wheat, straw 0.1 (b...

The price of associating with breeders in the cooperatively breeding chestnut-crowned babbler: foraging constraints, survival and sociality.

PubMed

Sorato, Enrico; Griffith, Simon C; Russell, Andy F

2016-09-01

Understanding the costs of living with breeders might offer new insights into the factors that counter evolutionary transitions from selfish individuals to cooperative societies. While selection on early dispersal is well understood, it is less clear whether costs are also associated with remaining with family members during subsequent breeding, a prerequisite to the evolution of kin-based cooperation. We propose and test the hypothesis that living in groups containing breeders is costly and that such costs are exacerbated by increasing group size. For example, in group-living central-place foragers, group members might suffer from resource depletion when foraging in a restricted area during breeding and significant costs of repeatedly travelling between foraging patches and the site of offspring. Using the cooperatively breeding chestnut-crowned babbler (Pomatostomus ruficeps), for which grouping during breeding is obligatory, we show that reproduction is associated with substantially reduced foraging areas and evidence of resource depletion, particularly in larger groups. Such effects largely persisted from the onset of incubation through to offspring independence 4-5 months later. All group members, irrespective of their breeder or helper status, lost significant body mass over this period, and, in males, mass loss was associated with reduced interannual survival. Although babblers are constrained from living outside of breeding groups due to high risks of predation and the poor success of breeding without helpers, we suggest that the effects we describe may generally select against group living during breeding attempts in species where constraints to independent breeding and costs of dispersal are less acute. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Determinants of spatial behavior of a tropical forest seed predator: The roles of optimal foraging, dietary diversification, and home range defense.

PubMed

Palminteri, Suzanne; Powell, George V N; Peres, Carlos A

2016-05-01

Specialized seed predators in tropical forests may avoid seasonal food scarcity and interspecific feeding competition but may need to diversify their daily diet to limit ingestion of any given toxin. Seed predators may, therefore, adopt foraging strategies that favor dietary diversity and resource monitoring, rather than efficient energy intake, as suggested by optimal foraging theory. We tested whether fine-scale space use by a small-group-living seed predator-the bald-faced saki monkey (Pithecia irrorata)-reflected optimization of short-term foraging efficiency, maximization of daily dietary diversity, and/or responses to the threat of territorial encroachment by neighboring groups. Food patches across home ranges of five adjacent saki groups were widely spread, but areas with higher densities of stems or food species were not allocated greater feeding time. Foraging patterns-specifically, relatively long daily travel paths that bypassed available fruiting trees and relatively short feeding bouts in undepleted food patches-suggest a strategy that maximizes dietary diversification, rather than "optimal" foraging. Travel distance was unrelated to the proportion of seeds in the diet. Moreover, while taxonomically diverse, the daily diets of our study groups were no more species-rich than randomly derived diets based on co-occurring available food species. Sakis preferentially used overlapping areas of their HRs, within which adjacent groups shared many food trees, yet the density of food plants or food species in these areas was no greater than in other HR areas. The high likelihood of depletion by neighboring groups of otherwise enduring food sources may encourage monitoring of peripheral food patches in overlap areas, even if at the expense of immediate energy intake, suggesting that between-group competition is a key driver of fine-scale home range use in sakis. © 2015 Wiley Periodicals, Inc.

Changes in period mRNA levels in the brain and division of labor in honey bee colonies

PubMed Central

Toma, Dan P.; Bloch, Guy; Moore, Darrell; Robinson, Gene E.

2000-01-01

Previous research showed that age-related division of labor in honey bees is associated with changes in activity rhythms; young adult bees perform hive tasks with no daily rhythms, whereas older bees forage with strong daily rhythms. We report that this division of labor is also associated with differences in both circadian rhythms and mRNA levels of period, a gene well known for its role in circadian rhythms. The level of period mRNA in the brain oscillated in bees of all ages, but was significantly higher at all times in foragers. Elevated period mRNA levels cannot be attributed exclusively to aging, because bees induced to forage precociously because of a change in social environment had levels similar to normal age foragers. These results extend the regulation of a “clock gene” to a social context and suggest that there are connections at the molecular level between division of labor and chronobiology in social insects. PMID:10841583

Plant Guide: Nineleaf biscuitroot (Lomatium triternatum [Pursh] Coulter and Rose)

Treesearch

Derek Tilley; Loren St. John; Dan Ogle; Nancy Shaw

2011-01-01

Nineleaf biscuitroot begins growth very early in the spring, often just following snow melt, providing crucial early forage for many wildlife and domestic animals. It is considered one of the most valuable forage species of the genus due to its large stature and high production levels. It is rated as having fair to very good forage for sheep and poor to good forage for...

Nocturnal activity and foraging of prairie raccoons (Procyon lotor) in North Dakota

USGS Publications Warehouse

Greenwood, R.J.

1982-01-01

Nocturnal activity and foraging of 39 radio-equipped raccoons (Procyon lotor) in eastern North Dakota were studied from April-July in 1974-1976. Sixteen of the raccoons were collected after foraging bouts for stomach content analysis. Raccoon activity consisted of running (13%), walking (49%) and local movement in confined areas (38%). Local movement was foraging on large or locally abundant food items. Adult males traveled farther in a night, ran twice as often, and moved locally only half as often as adult females and yearlings. Differences in activity patterns between adult females and yearlings were not detected. There was no difference among age-sex groups in use of foraging habitats. All raccoons foraged extensively in farmyards and wetlands. Stomach content analysis substantiated foraging determinations obtained by radiotelemetry. Principal foods were grain, aquatic animals, rodents, birds and bird eggs.

Increased plastic litter cover affects the foraging activity of the sandy intertidal gastropod Nassarius pullus.

PubMed

Aloy, Alexander B; Vallejo, Benjamin M; Juinio-Meñez, Marie Antonette

2011-08-01

This study analyzed the foraging behavior of the gastropod Nassarius pullus on garbage-impacted sandy shores of Talim Bay, Batangas, Philippines. The effect of different levels of plastic garbage cover on foraging efficiency was investigated. Controlled in situ baiting experiments were conducted to quantify aspects of foraging behavior as affected by the levels of plastic litter cover in the foraging area. The results of the study indicated that the gastropod's efficiency in locating and in moving towards a food item generally decreased as the level of plastic cover increased. Prolonged food searching time and increased self-burial in sand were highly correlated with increased plastic cover. The accuracy of orientation towards the actual position of the bait decreased significantly when the amount of plastic cover increased to 50%. These results are consistent with the significant decreases in the abundance of the gastropod observed during periods of deposition of large amounts of plastic and other debris on the shore. Copyright © 2011 Elsevier Ltd. All rights reserved.

Life-Long Radar Tracking of Bumblebees

PubMed Central

Lim, Ka S.; Reynolds, Andrew M.; Chittka, Lars

2016-01-01

Insect pollinators such as bumblebees play a vital role in many ecosystems, so it is important to understand their foraging movements on a landscape scale. We used harmonic radar to record the natural foraging behaviour of Bombus terrestris audax workers over their entire foraging career. Every flight ever made outside the nest by four foragers was recorded. Our data reveal where the bees flew and how their behaviour changed with experience, at an unprecedented level of detail. We identified how each bee’s flights fit into two categories—which we named exploration and exploitation flights—examining the differences between the two types of flight and how their occurrence changed over the course of the bees’ foraging careers. Exploitation of learned resources takes place during efficient, straight trips, usually to a single foraging location, and is seldom combined with exploration of other areas. Exploration of the landscape typically occurs in the first few flights made by each bee, but our data show that further exploration flights can be made throughout the bee’s foraging career. Bees showed striking levels of variation in how they explored their environment, their fidelity to particular patches, ratio of exploration to exploitation, duration and frequency of their foraging bouts. One bee developed a straight route to a forage patch within four flights and followed this route exclusively for six days before abandoning it entirely for a closer location; this second location had not been visited since her first exploratory flight nine days prior. Another bee made only rare exploitation flights and continued to explore widely throughout its life; two other bees showed more frequent switches between exploration and exploitation. Our data shed light on the way bumblebees balance exploration of the environment with exploitation of resources and reveal extreme levels of variation between individuals. PMID:27490662

Life-Long Radar Tracking of Bumblebees.

PubMed

Woodgate, Joseph L; Makinson, James C; Lim, Ka S; Reynolds, Andrew M; Chittka, Lars

2016-01-01

Insect pollinators such as bumblebees play a vital role in many ecosystems, so it is important to understand their foraging movements on a landscape scale. We used harmonic radar to record the natural foraging behaviour of Bombus terrestris audax workers over their entire foraging career. Every flight ever made outside the nest by four foragers was recorded. Our data reveal where the bees flew and how their behaviour changed with experience, at an unprecedented level of detail. We identified how each bee's flights fit into two categories-which we named exploration and exploitation flights-examining the differences between the two types of flight and how their occurrence changed over the course of the bees' foraging careers. Exploitation of learned resources takes place during efficient, straight trips, usually to a single foraging location, and is seldom combined with exploration of other areas. Exploration of the landscape typically occurs in the first few flights made by each bee, but our data show that further exploration flights can be made throughout the bee's foraging career. Bees showed striking levels of variation in how they explored their environment, their fidelity to particular patches, ratio of exploration to exploitation, duration and frequency of their foraging bouts. One bee developed a straight route to a forage patch within four flights and followed this route exclusively for six days before abandoning it entirely for a closer location; this second location had not been visited since her first exploratory flight nine days prior. Another bee made only rare exploitation flights and continued to explore widely throughout its life; two other bees showed more frequent switches between exploration and exploitation. Our data shed light on the way bumblebees balance exploration of the environment with exploitation of resources and reveal extreme levels of variation between individuals.

The influence of foraging mode and arid adaptation on the basal metabolic rates of burrowing mammals.

PubMed

White, Craig R

2003-01-01

Two competing but nonexclusive hypotheses to explain the reduced basal metabolic rate (BMR) of mammals that live and forage underground (fossorial species) are examined by comparing this group with burrowing mammals that forage on the surface (semifossorial species). These hypotheses suggest that the low BMR of fossorial species either compensates for the enormous energetic demands of subterranean foraging (the cost-of-burrowing hypothesis) or prevents overheating in closed burrow systems (the thermal-stress hypothesis). Because phylogentically informed allometric analysis showed that arid burrowing mammals have a significantly lower BMR than mesic ones, fossorial and semifossorial species were compared within these groups. The BMRs of mesic fossorial and semifossorial mammals could not be reliably distinguished, nor could the BMRs of large (>77 g) arid fossorial and semifossorial mammals. This finding favours the thermal-stress hypothesis, because the groups appear to have similar BMRs despite differences in foraging costs. However, in support of the cost-of-burrowing hypothesis, small (<77 g) arid fossorial mammals were found to have a significantly lower BMR than semifossorial mammals of the similar size. Given the high mass-specific metabolic rates of small animals, they are expected to be under severe energy and water stress in arid environments. Under such conditions, the greatly reduced BMR of small fossorial species may compensate for the enormous energetic demands of subterranean foraging.

Is genetic engineering ever going to take off in forage, turf and bioenergy crop breeding?

PubMed

Wang, Zeng-Yu; Brummer, E Charles

2012-11-01

Genetic engineering offers the opportunity to generate unique genetic variation that is either absent in the sexually compatible gene pool or has very low heritability. The generation of transgenic plants, coupled with breeding, has led to the production of widely used transgenic cultivars in several major cash crops, such as maize, soybean, cotton and canola. The process for regulatory approval of genetically engineered crops is slow and subject to extensive political interference. The situation in forage grasses and legumes is more complicated. Most widely grown forage, turf and bioenergy species (e.g. tall fescue, perennial ryegrass, switchgrass, alfalfa, white clover) are highly self-incompatible and outcrossing. Compared with inbreeding species, they have a high potential to pass their genes to adjacent plants. A major biosafety concern in these species is pollen-mediated transgene flow. Because human consumption is indirect, risk assessment of transgenic forage, turf and bioenergy species has focused on their environmental or ecological impacts. Although significant progress has been made in genetic modification of these species, commercialization of transgenic cultivars is very limited because of the stringent and costly regulatory requirements. To date, the only transgenic forage crop deregulated in the US is 'Roundup Ready' (RR) alfalfa. The approval process for RR alfalfa was complicated, involving several rounds of regulation, deregulation and re-regulation. Nevertheless, commercialization of RR alfalfa is an important step forward in regulatory approval of a perennial outcrossing forage crop. As additional transgenic forage, turf and bioenergy crops are generated and tested, different strategies have been developed to meet regulatory requirements. Recent progress in risk assessment and deregulation of transgenic forage and turf species is summarized and discussed.

Is genetic engineering ever going to take off in forage, turf and bioenergy crop breeding?

PubMed Central

Wang, Zeng-Yu; Brummer, E. Charles

2012-01-01

Background Genetic engineering offers the opportunity to generate unique genetic variation that is either absent in the sexually compatible gene pool or has very low heritability. The generation of transgenic plants, coupled with breeding, has led to the production of widely used transgenic cultivars in several major cash crops, such as maize, soybean, cotton and canola. The process for regulatory approval of genetically engineered crops is slow and subject to extensive political interference. The situation in forage grasses and legumes is more complicated. Scope Most widely grown forage, turf and bioenergy species (e.g. tall fescue, perennial ryegrass, switchgrass, alfalfa, white clover) are highly self-incompatible and outcrossing. Compared with inbreeding species, they have a high potential to pass their genes to adjacent plants. A major biosafety concern in these species is pollen-mediated transgene flow. Because human consumption is indirect, risk assessment of transgenic forage, turf and bioenergy species has focused on their environmental or ecological impacts. Although significant progress has been made in genetic modification of these species, commercialization of transgenic cultivars is very limited because of the stringent and costly regulatory requirements. To date, the only transgenic forage crop deregulated in the US is ‘Roundup Ready’ (RR) alfalfa. The approval process for RR alfalfa was complicated, involving several rounds of regulation, deregulation and re-regulation. Nevertheless, commercialization of RR alfalfa is an important step forward in regulatory approval of a perennial outcrossing forage crop. As additional transgenic forage, turf and bioenergy crops are generated and tested, different strategies have been developed to meet regulatory requirements. Recent progress in risk assessment and deregulation of transgenic forage and turf species is summarized and discussed. PMID:22378838

Avoidance of plants unsuitable for the symbiotic fungus in leaf-cutting ants: Learning can take place entirely at the colony dump.

PubMed

Arenas, Andrés; Roces, Flavio

2017-01-01

Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump. In order to investigate whether cues available in the waste chamber induce plant avoidance in naïve subcolonies, we exchanged the waste produced by subcolonies fed either fungicide-treated privet leaves or untreated leaves and measured the acceptance of untreated privet leaves before and after the exchange of waste. Second, we evaluated whether foragers could perceive the avoidance cues directly at the dump by quantifying the visits of labeled foragers to the waste chamber. Finally, we asked whether foragers learn to specifically avoid untreated leaves of a plant after a confinement over 3 hours in the dump of subcolonies that were previously fed fungicide-treated leaves of that species. After the exchange of the waste chambers, workers from subcolonies that had access to waste from fungicide-treated privet leaves learned to avoid that plant. One-third of the labeled foragers visited the dump. Furthermore, naïve foragers learned to avoid a specific, previously unsuitable plant if exposed solely to cues of the dump during confinement. We suggest that cues at the dump enable foragers to predict the unsuitable effects of plants even if they had never been experienced in the fungus garden.

Avoidance of plants unsuitable for the symbiotic fungus in leaf-cutting ants: Learning can take place entirely at the colony dump

PubMed Central

Roces, Flavio

2017-01-01

Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump. In order to investigate whether cues available in the waste chamber induce plant avoidance in naïve subcolonies, we exchanged the waste produced by subcolonies fed either fungicide-treated privet leaves or untreated leaves and measured the acceptance of untreated privet leaves before and after the exchange of waste. Second, we evaluated whether foragers could perceive the avoidance cues directly at the dump by quantifying the visits of labeled foragers to the waste chamber. Finally, we asked whether foragers learn to specifically avoid untreated leaves of a plant after a confinement over 3 hours in the dump of subcolonies that were previously fed fungicide-treated leaves of that species. After the exchange of the waste chambers, workers from subcolonies that had access to waste from fungicide-treated privet leaves learned to avoid that plant. One-third of the labeled foragers visited the dump. Furthermore, naïve foragers learned to avoid a specific, previously unsuitable plant if exposed solely to cues of the dump during confinement. We suggest that cues at the dump enable foragers to predict the unsuitable effects of plants even if they had never been experienced in the fungus garden. PMID:28273083

Late-instar Behavior of Aedes aegypti (Diptera: Culicidae) Larvae in Different Thermal and Nutritive Environments.

PubMed

Reiskind, Michael H; Janairo, M Shawn

2015-09-01

The effects of temperature on ectotherm growth have been well documented. How temperature affects foraging behavior is less well explored, and has not been studied in larval mosquitoes. We hypothesized that temperature changes foraging behavior in the aquatic larval phase of the mosquito, Aedes aegypti L. Based on empirical results in other systems, we predicted that foraging effort would increase at higher temperatures in these insects. We tested this prediction over three temperature conditions at two food levels. We measured behaviors by video recording replicated cohorts of fourth-instar mosquitoes and assessing individual behavior and time budgets using an ethogram. We found both food level and temperature had significant impacts on larval foraging behavior, with more time spent actively foraging at low food levels and at low temperatures, and more occurrences of active foraging at both temperature extremes. These results are contrary to some of our predictions, but fit into theoretical responses to temperature based upon dynamic energy budget models. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Three-dimensional interstitial space mediates predator foraging success in different spatial arrangements.

PubMed

Hesterberg, Stephen G; Duckett, C Cole; Salewski, Elizabeth A; Bell, Susan S

2017-04-01

Identifying and quantifying the relevant properties of habitat structure that mediate predator-prey interactions remains a persistent challenge. Most previous studies investigate effects of structural density on trophic interactions and typically quantify refuge quality using one or two-dimensional metrics. Few consider spatial arrangement of components (i.e., orientation and shape) and often neglect to measure the total three-dimensional (3D) space available as refuge. This study tests whether the three-dimensionality of interstitial space, an attribute produced by the spatial arrangement of oyster (Crassostrea virginica) shells, impacts the foraging success of nektonic predators (primary blue crab, Callinectes sapidus) on mud crab prey (Eurypanopeus depressus) in field and mesocosm experiments. Interstices of 3D-printed shell mimics were manipulated by changing either their orientation (angle) or internal shape (crevice or channel). In both field and mesocosm experiments, under conditions of constant structural density, predator foraging success was influenced by 3D aspects of interstitial space. Proportional survivorship of tethered mud crabs differed significantly as 3D interstitial space varied by orientation, displaying decreasing prey survivorship as angle of orientation increased (0° = 0.76, 22.5° = 0.13, 45° = 0.0). Tethered prey survivorship was high when 3D interstitial space of mimics was modified by internal shape (crevice survivorship = 0.89, channel survivorship = 0.96) and these values did not differ significantly. In mesocosms, foraging success of blue crabs varied with 3D interstitial space as mean proportional survivorship (± SE) of mud crabs was significantly lower in 45° (0.27 ± 0.06) vs. 0° (0.86 ± 0.04) orientations and for crevice (0.52 ± 0.11) vs. channel shapes (0.95 ± 0.02). These results suggest that 3D aspects of interstitial space, which have direct relevance to refuge quality, can strongly influence foraging success in our oyster reef habitat. Our findings highlight the importance of spatial arrangement in mediating consumptive pathways in hard-structured habitats and demonstrate how quantifying the three-dimensionality of living space captures aspects of habitat structure that have been missing from previous empirical studies of trophic interactions and structural complexity. © 2017 by the Ecological Society of America.

Foundations of cumulative culture in apes: improved foraging efficiency through relinquishing and combining witnessed behaviours in chimpanzees (Pan troglodytes).

PubMed

Davis, Sarah J; Vale, Gillian L; Schapiro, Steven J; Lambeth, Susan P; Whiten, Andrew

2016-10-24

A vital prerequisite for cumulative culture, a phenomenon often asserted to be unique to humans, is the ability to modify behaviour and flexibly switch to more productive or efficient alternatives. Here, we first established an inefficient solution to a foraging task in five captive chimpanzee groups (N = 19). Three groups subsequently witnessed a conspecific using an alternative, more efficient, solution. When participants could successfully forage with their established behaviours, most individuals did not switch to this more efficient technique; however, when their foraging method became substantially less efficient, nine chimpanzees with socially-acquired information (four of whom witnessed additional human demonstrations) relinquished their old behaviour in favour of the more efficient one. Only a single chimpanzee in control groups, who had not witnessed a knowledgeable model, discovered this. Individuals who switched were later able to combine components of their two learned techniques to produce a more efficient solution than their extensively used, original foraging method. These results suggest that, although chimpanzees show a considerable degree of conservatism, they also have an ability to combine independent behaviours to produce efficient compound action sequences; one of the foundational abilities (or candidate mechanisms) for human cumulative culture.

RNAi-mediated silencing of vitellogenin gene function turns honeybee ( Apis mellifera) workers into extremely precocious foragers

NASA Astrophysics Data System (ADS)

Marco Antonio, David Santos; Guidugli-Lazzarini, Karina Rosa; Do Nascimento, Adriana Mendes; Simões, Zilá Luz Paulino; Hartfelder, Klaus

2008-10-01

The switch from within-hive activities to foraging behavior is a major transition in the life cycle of a honeybee ( Apis mellifera) worker. A prominent regulatory role in this switch has long been attributed to juvenile hormone (JH), but recent evidence also points to the yolk precursor protein vitellogenin as a major player in behavioral development. In the present study, we injected vitellogenin double-stranded RNA (dsVg) into newly emerged worker bees of Africanized genetic origin and introduced them together with controls into observation hives to record flight behavior. RNA interference-mediated silencing of vitellogenin gene function shifted the onset of long-duration flights (>10 min) to earlier in life (by 3 4 days) when compared with sham and untreated control bees. In fact, dsVg bees were observed conducting such flights extremely precociously, when only 3 days old. Short-duration flights (<10 min), which bees usually perform for orientation and cleaning, were not affected. Additionally, we found that the JH titer in dsVg bees collected after 7 days was not significantly different from the controls. The finding that depletion of the vitellogenin titer can drive young bees to become extremely precocious foragers could imply that vitellogenin is the primary switch signal. At this young age, downregulation of vitellogenin gene activity apparently had little effect on the JH titer. As this unexpected finding stands in contrast with previous results on the vitellogenin/JH interaction at a later age, when bees normally become foragers, we propose a three-step sequence in the constellation of physiological parameters underlying behavioral development.

Short-term prey field lability constrains individual specialisation in resource selection and foraging site fidelity in a marine predator.

PubMed

Courbin, Nicolas; Besnard, Aurélien; Péron, Clara; Saraux, Claire; Fort, Jérôme; Perret, Samuel; Tornos, Jérémy; Grémillet, David

2018-04-16

Spatio-temporally stable prey distributions coupled with individual foraging site fidelity are predicted to favour individual resource specialisation. Conversely, predators coping with dynamic prey distributions should diversify their individual diet and/or shift foraging areas to increase net intake. We studied individual specialisation in Scopoli's shearwaters (Calonectris diomedea) from the highly dynamic Western Mediterranean, using daily prey distributions together with resource selection, site fidelity and trophic-level analyses. As hypothesised, we found dietary diversification, low foraging site fidelity and almost no individual specialisation in resource selection. Crucially, shearwaters switched daily foraging tactics, selecting areas with contrasting prey of varying trophic levels. Overall, information use and plastic resource selection of individuals with reduced short-term foraging site fidelity allow predators to overcome prey field lability. Our study is an essential step towards a better understanding of individual responses to enhanced environmental stochasticity driven by global changes, and of pathways favouring population persistence. © 2018 John Wiley & Sons Ltd/CNRS.

Vision, touch and object manipulation in Senegal parrots Poicephalus senegalus

PubMed Central

Demery, Zoe P.; Chappell, Jackie; Martin, Graham R.

2011-01-01

Parrots are exceptional among birds for their high levels of exploratory behaviour and manipulatory abilities. It has been argued that foraging method is the prime determinant of a bird's visual field configuration. However, here we argue that the topography of visual fields in parrots is related to their playful dexterity, unique anatomy and particularly the tactile information that is gained through their bill tip organ during object manipulation. We measured the visual fields of Senegal parrots Poicephalus senegalus using the ophthalmoscopic reflex technique and also report some preliminary observations on the bill tip organ in this species. We found that the visual fields of Senegal parrots are unlike those described hitherto in any other bird species, with both a relatively broad frontal binocular field and a near comprehensive field of view around the head. The behavioural implications are discussed and we consider how extractive foraging and object exploration, mediated in part by tactile cues from the bill, has led to the absence of visual coverage of the region below the bill in favour of more comprehensive visual coverage above the head. PMID:21525059

The nurse's load: early-life exposure to brood-rearing affects behavior and lifespan in honey bees (Apis mellifera).

PubMed

Amdam, Gro V; Rueppell, Olav; Fondrk, M Kim; Page, Robert E; Nelson, C Mindy

2009-01-01

Long-lived honey bees (Apis mellifera) develop in fall. This pattern may be explained by reduced nurse loads. When the amount of brood in colonies declines as a function of adverse foraging conditions, adult bees build up surplus nutrient stores that include vitellogenin, a behavioral affector protein that also can increase lifespan. Although the seasonal reduction in exposure to nursing tasks predictably results in vitellogenin accumulation, the assumption that long-lived adults thereby develop is confounded by a concomitant decline in foraging effort. Foraging activity reduces lifespan, and is influenced by colony resource consumption, brood pheromones, availability of nectar and pollen, and weather. Here, we perform the first controlled experiment where the nursing environment of pre-foraging sister bees was set to vary, while their foraging environment later was set to be the same. We measure vitellogenin, age at foraging onset and lifespan. We establish that reduced brood-rearing increases vitellogenin levels, and delays foraging onset and death. Longevity is largely explained by the effect of nursing on the onset of foraging behavior, but is also influenced by the level of brood-rearing independent of behavioral change. Our findings are consistent with the roles of vitellogenin in regulation of honey bee behavior and lifespan.

Children's Learning of Number Words in an Indigenous Farming-Foraging Group

ERIC Educational Resources Information Center

Piantadosi, Steven T.; Jara-Ettinger, Julian; Gibson, Edward

2014-01-01

We show that children in the Tsimane', a farming-foraging group in the Bolivian rain-forest, learn number words along a similar developmental trajectory to children from industrialized countries. Tsimane' children successively acquire the first three or four number words before fully learning how counting works. However, their learning is…

The ontogeny of handling hard-to-process food in wild brown capuchins (Cebus apella apella): evidence from foraging on the fruit of Maximiliana maripa.

PubMed

Gunst, Noëlle; Leca, Jean-Baptiste; Boinski, Sue; Fragaszy, Dorothy

2010-11-01

We examined age-related differences in wild brown capuchins' foraging efficiency and the food-processing behaviors directed toward maripa palm fruit (Maximiliana maripa). A detailed comparison of the different foraging techniques showed that plucking the fruit from the infructescence constituted the main difficulty of this task. Foraging efficiency tended to increase with age, with a threshold at which sufficient strength allowed immatures by the age of three to reach adult-level efficiency. Youngsters spent more time than older individuals browsing the infructescence and pulling the fruit in an attempt to harvest it. Infants tried to compensate for their inability to pluck fruit by adopting alternative strategies but with low payback, such as gnawing unplucked fruit and opportunistically scrounging others' partially processed food. Although around 2 years of age, young capuchins exhibited all of the behaviors used by adults, they did not reach adult-level proficiency at feeding on maripa until about 3 years (older juveniles). We compared this developmental pattern with that of extractive foraging on beetle larvae (Myelobia sp.) hidden in bamboo stalks, a more difficult food for these monkeys [Gunst N, Boinski S, Fragaszy DM. Behaviour 145:195-229, 2008]. For maripa, the challenge was mainly physical (plucking the fruit) once a tree was encountered, whereas for larvae, the challenge was primarily perceptual (locating the hidden larvae). For both foods, capuchins practice for years before achieving adult-level foraging competence, and the timeline is extended for larvae foraging (until 6 years) compared with maripa (3 years). The differing combinations of opportunities and challenges for learning to forage on these different foods illustrate how young generalist foragers (i.e. exploiting a large number of animal and plant species) may compensate for their low efficiency in extractive foraging tasks by showing earlier competence in processing less difficult but nutritious foods, such as maripa fruit. © 2010 Wiley-Liss, Inc.

Effect of Interactions between Harvester Ants on Forager Decisions

PubMed Central

Davidson, Jacob D.; Arauco-Aliaga, Roxana P.; Crow, Sam; Gordon, Deborah M.; Goldman, Mark S.

2017-01-01

Harvester ant colonies adjust their foraging activity to day-to-day changes in food availability and hour-to-hour changes in environmental conditions. This collective behavior is regulated through interactions, in the form of brief antennal contacts, between outgoing foragers and returning foragers with food. Here we consider how an ant, waiting in the entrance chamber just inside the nest entrance, uses its accumulated experience of interactions to decide whether to leave the nest to forage. Using videos of field observations, we tracked the interactions and foraging decisions of ants in the entrance chamber. Outgoing foragers tended to interact with returning foragers at higher rates than ants that returned to the deeper nest and did not forage. To provide a mechanistic framework for interpreting these results, we develop a decision model in which ants make decisions based upon a noisy accumulation of individual contacts with returning foragers. The model can reproduce core trends and realistic distributions for individual ant interaction statistics, and suggests possible mechanisms by which foraging activity may be regulated at an individual ant level. PMID:28758093

Breeding chronology and social interactions affect ungulate foraging behavior at a concentrated food resource

PubMed Central

Cohen, Bradley S.; Miller, Karl V.

2017-01-01

Prey species must balance predator avoidance behavior with other essential activities including foraging, breeding, and social interactions. Anti-predator behaviors such as vigilance can impede resource acquisition rates by altering foraging behavior. However, in addition to predation risk, foraging behavior may also be affected by socio-sexual factors including breeding chronology and social interactions. Therefore, we investigated how time-of-day, distance-to-forest, group size, social interactions (presence of different sex-age class), and breeding chronology (pre-breeding, breeding, post-breeding seasons) affected probability of feeding (hereafter: feeding) for different sex and age-classes (mature males, immature males, adult females, and juveniles) of white-tailed deer at feed sites. We developed a set of candidate models consisting of social, habitat, reproductive, and abiotic factors and combinations of these factors. We then used generalized linear mixed models (GLMMs) to estimate the probability of feeding and used model averaging of competing models for multimodel inference. Each adult sex-age class’ feeding was influenced by breeding chronology. Juveniles were more likely to be feeding than adults in all seasons. Feeding increased with group size for all sex-age classes. The presence of a mature male negatively influenced the feeding of immature males and juveniles were more likely to be feeding when an adult female was present. Feeding decreased with increasing distance-to-forest for mature males but not for other sex-age classes. Our results indicate that each sex-age class modulates vigilance levels in response to socio-sexual factors according to the unique pressures placed upon them by their reproductive status and social rank. PMID:28591136

Plasticity of collective behavior in a nomadic early spring folivore

PubMed Central

Despland, Emma

2013-01-01

Collective behavior in the forest tent caterpillar (Malacosoma disstria) meets the thermal constraints of being an early spring folivore, but introduces other constraints in food choice. These are minimized by state-dependent, inter-individual, and ontogenetic variations in responses to social cues. Forest tent caterpillars use pheromone trails and tactile communication among colony members to stay together during foraging. At the group level, these rules lead to cohesive synchronized collective nomadic foraging, in which the colony travels en masse between feeding and resting sites. This paper proposes that synchronized collective locomotion prevents individuals from becoming separated from the colony and hence permits them to reap the advantages of group-living, notably collective basking to increase their body temperature above ambient and collective defense against natural enemies. However, this cohesive behavior also implies conservative foraging, and colonies can become trapped on poor food sources. High fidelity to pheromone trails leads to strong amplification of an initial choice, such that colonies seldom abandon the first food source contacted, even if a better one is nearby. The risk of this trapping is modulated both by consistent inter-individual variations in exploratory behavior and by inner state. Colonies consisting of active-phenotype or protein-deprived individuals that explore more-off trails exhibit greater collective flexibility in foraging. An ontogenetic shift toward more independent movement occurs as caterpillars grow. This leads to colony break-up as the season advances. Selection pressures facing older caterpillars favor solitary living more than in the earlier instars. Caterpillars respond to this predictably changing environment by altering their behavioral rules as they grow. PMID:23526800

The Evolution of Different Forms of Sociality: Behavioral Mechanisms and Eco-Evolutionary Feedback

PubMed Central

van der Post, Daniel J.; Verbrugge, Rineke; Hemelrijk, Charlotte K.

2015-01-01

Different forms of sociality have evolved via unique evolutionary trajectories. However, it remains unknown to what extent trajectories of social evolution depend on the specific characteristics of different species. Our approach to studying such trajectories is to use evolutionary case-studies, so that we can investigate how grouping co-evolves with a multitude of individual characteristics. Here we focus on anti-predator vigilance and foraging. We use an individual-based model, where behavioral mechanisms are specified, and costs and benefits are not predefined. We show that evolutionary changes in grouping alter selection pressures on vigilance, and vice versa. This eco-evolutionary feedback generates an evolutionary progression from “leader-follower” societies to “fission-fusion” societies, where cooperative vigilance in groups is maintained via a balance between within- and between-group selection. Group-level selection is generated from an assortment that arises spontaneously when vigilant and non-vigilant foragers have different grouping tendencies. The evolutionary maintenance of small groups, and cooperative vigilance in those groups, is therefore achieved simultaneously. The evolutionary phases, and the transitions between them, depend strongly on behavioral mechanisms. Thus, integrating behavioral mechanisms and eco-evolutionary feedback is critical for understanding what kinds of intermediate stages are involved during the evolution of particular forms of sociality. PMID:25629313

The evolution of different forms of sociality: behavioral mechanisms and eco-evolutionary feedback.

PubMed

van der Post, Daniel J; Verbrugge, Rineke; Hemelrijk, Charlotte K

2015-01-01

Different forms of sociality have evolved via unique evolutionary trajectories. However, it remains unknown to what extent trajectories of social evolution depend on the specific characteristics of different species. Our approach to studying such trajectories is to use evolutionary case-studies, so that we can investigate how grouping co-evolves with a multitude of individual characteristics. Here we focus on anti-predator vigilance and foraging. We use an individual-based model, where behavioral mechanisms are specified, and costs and benefits are not predefined. We show that evolutionary changes in grouping alter selection pressures on vigilance, and vice versa. This eco-evolutionary feedback generates an evolutionary progression from "leader-follower" societies to "fission-fusion" societies, where cooperative vigilance in groups is maintained via a balance between within- and between-group selection. Group-level selection is generated from an assortment that arises spontaneously when vigilant and non-vigilant foragers have different grouping tendencies. The evolutionary maintenance of small groups, and cooperative vigilance in those groups, is therefore achieved simultaneously. The evolutionary phases, and the transitions between them, depend strongly on behavioral mechanisms. Thus, integrating behavioral mechanisms and eco-evolutionary feedback is critical for understanding what kinds of intermediate stages are involved during the evolution of particular forms of sociality.

Volatile fatty acid profile for grass hay or alfalfa hay fed to alpacas (Vicugna pacos).

PubMed

Oldham, C L; Robinson, T F; Hunter, Z R; Taylor, L; White, J; Johnston, N P

2014-10-01

The purpose of this study was to determine the diurnal composition and concentration of volatile fatty acids (VFA) and to determine VFA composition and concentration differences between stomach compartment 1 (C1) and caecum of alpacas fed grass and alfalfa hay. The study was divided into two experiments. In Experiment 1 (EXP 1), 10 male alpacas (3+ years old, 65 kg BW) were divided into two groups, housed in drylot pens, provided ad libitum water and fed alfalfa (AH) or grass hay (GH) for 30 days. The alpacas were slaughtered and the digestive tract collected, divided into sub-tract sections, weighed and digesta sampled for pH, dry matter (DM) and NDF. Volatile fatty acid composition and concentration were determined on C1 and caecal material. Four adult male (3+ years old, 60 kg BW), C1 fistulated alpacas were housed in metabolism crates and divided into two forage groups for Experiment 2 (EXP 2). Alpacas were fed the forages as in EXP 1. Diurnal C1 VFA samples were drawn at 1, 3, 6, 9, 12, 18 and 24 h post-feeding. There were no differences between forages for tract weight, C1 and caecum digesta DM or NDF. Differences were noted (p < 0.05) for pH between forages and sub-tract site. Volatile fatty acids concentrations were different (p < 0.05) for forage and site, and total VFA was higher for AH than GH (110.6 and 79.1 mm) and C1 than caecum (40.7 and 27.6 mm). Proportion of VFA was significant (p < 0.05) for forage and site, C1 acetate highest for GH (84.8 vs. 74.0 mm) and caecum acetate 83.7 and 76.2 mm for GH and AH respectively. These data demonstrate the level of VFA produced in C1 and the caecum of alpacas and the diurnal VFA patterns. Composition of VFA is similar to other ruminant species. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

Persistent producer-scrounger relationships in bats.

PubMed

Harten, Lee; Matalon, Yasmin; Galli, Naama; Navon, Hagit; Dor, Roi; Yovel, Yossi

2018-02-01

Social foraging theory suggests that group-living animals gain from persistent social bonds, which lead to increased tolerance in competitive foraging and information sharing. Bats are among the most social mammals, often living in colonies of tens to thousands of individuals for dozens of years, yet little is known about their social foraging dynamics. We observed three captive bat colonies for over a year, quantifying >13,000 social foraging interactions. We found that individuals consistently used one of two foraging strategies, either producing (collecting) food themselves or scrounging it directly from the mouth of other individuals. Individual foraging types were consistent over at least 16 months except during the lactation period when females shifted toward producing. Scroungers intentionally selected whom to interact with when socially foraging, thus generating persistent nonrandom social relationships with two to three specific producers. These persistent producer-scrounger relationships seem to reduce aggression over time. Finally, scrounging was highly correlated with vigilance, and we hypothesize that vigilant-prone individuals turn to scrounging in the wild to mitigate the risk of landing on a potentially unsafe fruit tree. We find the bat colony to be a rich and dynamic social system, which can serve as a model to study the role that social foraging plays in the evolution of mammalian sociality. Our results highlight the importance of considering individual tendencies when exploring social behavior patterns of group-living animals. These tendencies further emphasize the necessity of studying social networks over time.

Persistent producer-scrounger relationships in bats

PubMed Central

Harten, Lee; Matalon, Yasmin; Galli, Naama; Navon, Hagit; Dor, Roi; Yovel, Yossi

2018-01-01

Social foraging theory suggests that group-living animals gain from persistent social bonds, which lead to increased tolerance in competitive foraging and information sharing. Bats are among the most social mammals, often living in colonies of tens to thousands of individuals for dozens of years, yet little is known about their social foraging dynamics. We observed three captive bat colonies for over a year, quantifying >13,000 social foraging interactions. We found that individuals consistently used one of two foraging strategies, either producing (collecting) food themselves or scrounging it directly from the mouth of other individuals. Individual foraging types were consistent over at least 16 months except during the lactation period when females shifted toward producing. Scroungers intentionally selected whom to interact with when socially foraging, thus generating persistent nonrandom social relationships with two to three specific producers. These persistent producer-scrounger relationships seem to reduce aggression over time. Finally, scrounging was highly correlated with vigilance, and we hypothesize that vigilant-prone individuals turn to scrounging in the wild to mitigate the risk of landing on a potentially unsafe fruit tree. We find the bat colony to be a rich and dynamic social system, which can serve as a model to study the role that social foraging plays in the evolution of mammalian sociality. Our results highlight the importance of considering individual tendencies when exploring social behavior patterns of group-living animals. These tendencies further emphasize the necessity of studying social networks over time. PMID:29441356

Ploidy level and genetic diversity in the Genus Paspalum, group disticha

USDA-ARS?s Scientific Manuscript database

Paspalum vaginatum Sw. is a grass species of increasing importance worldwide due to its salt tolerance and its ability to serve as forage, as ground cover for erosion control, and as turf for sports surfaces in vulnerable areas in the tropics and sub-tropics. Though it is a member of one of the lar...

[Effects of Electroacupunctrue Combined with Dietary Control on Peroxisome Proliferator-activa- ted Receptor-α, and Liver Fatty Acid-binding Protein Levels in Non-alcoholic Fatty Liver Disease Rats].

PubMed

Zhang, Yi; Tang, Cheng-lin; Tian, Yuan; Yuan, Hai-zhou; Yang, Hui; Tang, Nian-zhen; Gao, Rui-qi; Cao, Jing

2015-10-01

To observe the effect of electroacupunctrue (EA) intervention or EA combined with dietary control on peroxisome proliferator-activated receptor (PPAR)-α, and liver fatty acid-binding protein (L-FABP) levels in non-alcoholic fatty liver disease (NAFLD) rats, so as to reveal its mechanism underlying improvement of NAFLD. Sixty SD male rats were randomly divided into common diet (control) group (n = 10) and high-fat diet group (n = 45). The NAFLD model was established by feeding the animals with high-fat forage (HFF, including cholesterol, sodium cholate, propylthiouracil, sucrose, lard and common forage) for 5 weeks. Forty NAFLD rats were then randomized into model, EA + HFF, low-fat forage (LFF) and EA+ LFF groups (n = 10 rats in each group). EA (4 Hz/20 Hz, 3 mA) was applied to ipsilateral "Zusanli" (ST 36),"Sanyinjiao" (SP 6) and "Taichong" (LR 3) for 20 min, once daily for 4 weeks. The pathologic changes of the hepatic tissue were detected by H. E. staining. Serum total cholesterol (TC) and triglyceride (TG) contents were determined by using enzymatic methods, serum free fat acids (FFA) content was detected by colorimetry. The expression levels of PPAR-α and L-FABP protein and gene of the liver tissue were determined by Western blot and RT-PCR, respectively. H. E. staining showed that the hepatocytes presented moderate or severe bullous adipose degeneration in rats of the model group, vesicular steatosis in the EA + HFF and LFF groups, turned to almost normal but with small amount of lipid droplets in the EA + LFF group. The contents of serum TC, TG and FFA were significantly higher in the model group than in the control group (P < 0.05), and were obviously decreased in the EA + HFF, LFF and EA + LFF groups in comparison with the model group (P < 0.05). Compared to the control group, hepatic PPAR-α protein and mRNA were markedly down-regulated in the model group, and hepatic L-FABP protein and mRNA considerably up-regulated in the model group (P < 0.05). Following EA intervention and low fat diet feeding, PPAR-α protein and mRNA were markedly up-regulated while L-FABP protein and mRNA remarkably down-regulated in the EA + HFF, LFF and EA + LFF groups (P < 0.05). EA intervention or EA combined with dietary control can relieve hepatic pathological changes in NAFLD rats, which may be related to its effects in down-regulating blood lipid level and hepatic L-FABP protein and mRNA expression and in up-regulating PPAR-α protein and mRNA expression, and the effect of combined treatment was relatively better than simple EA or LFF treatment.

Behavioral and physiological responses to subgroup size and number of people in howler monkeys inhabiting a forest fragment used for nature-based tourism.

PubMed

Aguilar-Melo, Adriana R; Andresen, Ellen; Cristóbal-Azkarate, Jurgi; Arroyo-Rodríguez, Victor; Chavira, Roberto; Schondube, Jorge; Serio-Silva, Juan Carlos; Cuarón, Alfredo D

2013-11-01

Animals' responses to potentially threatening factors can provide important information for their conservation. Group size and human presence are potentially threatening factors to primates inhabiting small reserves used for recreation. We tested these hypotheses by evaluating behavioral and physiological responses in two groups of mantled howler monkeys (Alouatta palliata mexicana) at the "Centro Ecológico y Recreativo El Zapotal", a recreational forest reserve and zoo located in the Mexican state of Chiapas. Both groups presented fission-fusion dynamics, splitting into foraging subgroups which varied in size among, but not within days. Neither subgroup size nor number of people had an effect on fecal cortisol. Out of 16 behavioral response variables tested, the studied factors had effects on six: four were affected by subgroup size and two were affected by number of people. With increasing subgroup size, monkeys increased daily path lengths, rested less, increased foraging effort, and used more plant individuals for feeding. As the number of people increased, monkeys spent more time in lower-quality habitat, and less time engaged in social interactions. Although fecal cortisol levels were not affected by the factors studied, one of the monkey groups had almost twice the level of cortisol compared to the other group. The group with higher cortisol levels also spent significantly more time in the lower-quality habitat, compared to the other group. Our results suggest that particular behavioral adjustments might allow howler monkeys at El Zapotal to avoid physiological stress due to subgroup size and number of people. However, the fact that one of the monkey groups is showing increased cortisol levels may be interpreted as a warning sign, indicating that an adjustment threshold is being reached, at least for part of the howler monkey population in this forest fragment. © 2013 Wiley Periodicals, Inc.

Leader-based and self-organized communication: modelling group-mass recruitment in ants.

PubMed

Collignon, Bertrand; Deneubourg, Jean Louis; Detrain, Claire

2012-11-21

For collective decisions to be made, the information acquired by experienced individuals about resources' location has to be shared with naïve individuals through recruitment. Here, we investigate the properties of collective responses arising from a leader-based recruitment and a self-organized communication by chemical trails. We develop a generalized model based on biological data drawn from Tetramorium caespitum ant species of which collective foraging relies on the coupling of group leading and trail recruitment. We show that for leader-based recruitment, small groups of recruits have to be guided in a very efficient way to allow a collective exploitation of food while large group requires less attention from their leader. In the case of self-organized recruitment through a chemical trail, a critical value of trail amount has to be laid per forager in order to launch collective food exploitation. Thereafter, ants can maintain collective foraging by emitting signal intensity below this threshold. Finally, we demonstrate how the coupling of both recruitment mechanisms may benefit to collectively foraging species. These theoretical results are then compared with experimental data from recruitment by T. caespitum ant colonies performing group-mass recruitment towards a single food source. We evidence the key role of leaders as initiators and catalysts of recruitment before this leader-based process is overtaken by self-organised communication through trails. This model brings new insights as well as a theoretical background to empirical studies about cooperative foraging in group-living species. Copyright © 2012 Elsevier Ltd. All rights reserved.

40 CFR 180.298 - Methidathion; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Nut, tree, group 14 0.05 Olive 0.05 Safflower, seed 0.5 Sorghum, forage, forage 2.0 Sorghum, grain, forage 2.0 Sorghum, grain, grain 0.2 Sorghum, grain, stover 2.0 Sunflower, seed 0.5 Tangerine 6.0 (b... million Almond, hulls 6.0 Artichoke, globe 0.05 Citrus, oil 420.0 Cotton, undelinted seed 0.2 Fruit...

40 CFR 180.298 - Methidathion; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Nut, tree, group 14 0.05 Olive 0.05 Safflower, seed 0.5 Sorghum, forage, forage 2.0 Sorghum, grain, forage 2.0 Sorghum, grain, grain 0.2 Sorghum, grain, stover 2.0 Sunflower, seed 0.5 Tangerine 6.0 (b... million Almond, hulls 6.0 Artichoke, globe 0.05 Citrus, oil 420.0 Cotton, undelinted seed 0.2 Fruit...

Harvest-related edge effects on prey availability and foraging of hooded warblers in a bottomland hardwood forest

Treesearch

John C. Kilgo

2005-01-01

The effects of harvest-created canopy gaps in bottomland hardwood forests on arthropod abundance and, hence, the foraging ecology of birds are poorly understood. I predicted that arthropod abundance would be high near edges of group-selection harvest gaps and lower in the surrounding forest, and that male Hooded Warblers (Wilsonia citrina) foraging...

Helminths and human ancestral immune ecology: What is the evidence for high helminth loads among foragers?

PubMed

London, Douglas; Hruschka, Daniel

2014-01-01

Recent theories of human immune ecology have invoked high helminth loads as an important selection factor among early humans. However, few studies have assessed this assumption among extant human foragers. We review the current evidence for high helminth loads in documented forager populations and present new data from members of a Kawymeno Waorani forager group in Amazonian Ecuador (n = 16) compared with neighboring Kichwa subsistence farmers (n = 63). Stool samples indicated a near absence of helminths among the Kawymeno foraging group (6.25% with Ascaris lumbricoides and 0% with Ancylostoma duodenale or Trichuris trichiura). In contrast neighboring, isolated Kichwa subsistence farmers in a similar ecosystem had abundant helminth infestations (76.1% with Ascaris lumbricoides, 11.1% with Ancylostoma duodenale, and 1.5% with Trichuris trichiura). The presence of helminths among the Waorani and Kichwa was triangulated across multiple data sources, including presence in stool samples, medical exams, and 3 years of participant observation. These findings, coupled with the modern forager literature, raise questions as to whether helminths were prevalent enough in Paleolithic humans to be a unique evolutionary selective force in human physiology. Copyright © 2014 Wiley Periodicals, Inc.

Experimental evidence for route integration and strategic planning in wild capuchin monkeys.

PubMed

Janson, Charles H

2007-07-01

Both in captivity and the wild, primates are found to travel mostly to the nearest available resource, but they may skip over the closest resource and travel to more distant resources, which are often found to be more productive. This study examines the tradeoff between distance and reward in the foraging choices of one group of wild capuchin monkeys (Cebus apella nigritus) using feeding platforms in large-scale foraging experiments conducted over four years. Three feeding sites were arrayed in an oblique triangle, such that once the monkey group had chosen one site to feed, they had a choice between two remaining sites, a close one with less food and the other up to 2.3 times as far away but with more food. Sites were provisioned once per day. The capuchins generally chose the closer feeding site, even when the more distant site offered up to 12 times as much food. The distances to, rewards of, or various profitability measures applied to each alternative site individually did not explain the group's choices in ways consistent with foraging theory or principles of operant psychology. The group's site choices were predicted only by comparing efficiency measures of entire foraging pathways: (1) direct travel to the more rewarding distant site, versus (2) the longer 'detour' through the closer site on the way to the more distant one. The group chose the detour more often when the reward was larger and the added detour distance shorter. They appeared to be more sensitive to the absolute increase in detour distance than to the relative increase compared to the straight route. The qualitative and quantitative results agree with a simple rule: do not use the detour unless the energy gain from extra food outweighs the energy cost of extra travel. These results suggest that members of this group integrate information on spatial location, reward, and perhaps potential food competition in their choice of multi-site foraging routes, with important implications for social foraging.

Maintaining social cohesion is a more important determinant of patch residence time than maximizing food intake rate in a group-living primate, Japanese macaque (Macaca fuscata).

PubMed

Kazahari, Nobuko

2014-04-01

Animals have been assumed to employ an optimal foraging strategy (e.g., rate-maximizing strategy). In patchy food environments, intake rate within patches is positively correlated with patch quality, and declines as patches are depleted through consumption. This causes patch-leaving and determines patch residence time. In group-foraging situations, patch residence times are also affected by patch sharing. Optimal patch models for groups predict that patch residence times decrease as the number of co-feeding animals increases because of accelerated patch depletion. However, group members often depart patches without patch depletion, and their patch residence time deviates from patch models. It has been pointed out that patch residence time is also influenced by maintaining social proximity with others among group-living animals. In this study, the effects of maintaining social cohesion and that of rate-maximizing strategy on patch residence time were examined in Japanese macaques (Macaca fuscata). I hypothesized that foragers give up patches to remain in the proximity of their troop members. On the other hand, foragers may stay for a relatively long period when they do not have to abandon patches to follow the troop. In this study, intake rate and foraging effort (i.e., movement) did not change during patch residency. Macaques maintained their intake rate with only a little foraging effort. Therefore, the patches were assumed to be undepleted during patch residency. Further, patch residence time was affected by patch-leaving to maintain social proximity, but not by the intake rate. Macaques tended to stay in patches for short periods when they needed to give up patches for social proximity, and remained for long periods when they did not need to leave to keep social proximity. Patch-leaving and patch residence time that prioritize the maintenance of social cohesion may be a behavioral pattern in group-living primates.

Aging- and task-related resilience decline is linked to food responsiveness in highly social honey bees.

PubMed

Speth, Martin T; Kreibich, Claus D; Amdam, Gro V; Münch, Daniel

2015-05-01

Conventional invertebrate models of aging have provided striking examples for the influence of food- and nutrient-sensing on lifespan and stress resilience. On the other hand, studies in highly social insects, such as honey bees, have revealed how social context can shape very plastic life-history traits, for example flexible aging dynamics in the helper caste (workers). It is, however, not understood how food perception and stress resilience are connected in honey bee workers with different social task behaviors and aging dynamics. To explore this linkage, we tested if starvation resilience, which normally declines with age, depends on food responsiveness in honey bees. We studied two typically non-senesced groups of worker bees with different social task behaviors: mature nurses (caregivers) and mature foragers (food collectors). In addition, we included a group of old foragers for which functional senescence is well-established. Bees were individually scored for their food perception by measuring the gustatory response to different sucrose concentrations. Subsequently, individuals were tested for survival under starvation stress. We found that starvation stress resilience, but not gustatory responsiveness differed between workers with different social task behaviors (mature nurses vs. mature foragers). In addition starvation stress resilience differed between foragers with different aging progressions (mature foragers vs. old foragers). Control experiments confirmed that differences in starvation resilience between mature nurses and mature foragers were robust against changing experimental conditions, such as water provision and activity. For all worker groups we established that individuals with low gustatory responsiveness were more resilient to starvation stress. Finally, for the group of rapidly aging foragers we found that low food responsiveness was linked to a delayed age-related decline in starvation resilience. Our study highlights associations between reduced food perception, increased survival capacity and delayed aging in highly social honey bees. We discuss that these associations may involve canonical internal nutrient sensing pathways, which are shared between honey bees and animal models with less plastic aging dynamics. Copyright © 2015 Elsevier Inc. All rights reserved.

Isolation of Pseudobutyrivibrio ruminis and Pseudobutyrivibrio xylanivorans from rumen of Creole goats fed native forage diet.

PubMed

Grilli, D J; Cerón, M E; Paez, S; Egea, V; Schnittger, L; Cravero, S; Escudero, M Sosa; Allegretti, L; Arenas, G N

2013-09-01

We isolated and identified functional groups of bacteria in the rumen of Creole goats involved in ruminal fermentation of native forage shrubs. The functional bacterial groups were evaluated by comparing the total viable, total anaerobic, cellulolytic, hemicellulolytic, and amylolytic bacterial counts in the samples taken from fistulated goats fed native forage diet (Atriplex lampa and Prosopis flexuosa). Alfalfa hay and corn were used as control diet. The roll tubes method increased the possibility of isolating and 16S rDNA gene sequencing allowed definitive identification of bacterial species involved in the ruminal fermentation. The starch and fiber contents of the diets influenced the number of total anaerobic bacteria and fibrolytic and amylolytic functional groups. Pseudobutyrivibrio ruminis and Pseudobutyrivibrio xylanivorans were the main species isolated and identified. The identification of bacterial strains involved in the rumen fermentation helps to explain the ability of these animals to digest fiber plant cell wall contained in native forage species.

Differences in Forage-Acquisition and Fungal Enzyme Activity Contribute to Niche Segregation in Panamanian Leaf-Cutting Ants

PubMed Central

Kooij, Pepijn W.; Liberti, Joanito; Giampoudakis, Konstantinos; Schiøtt, Morten; Boomsma, Jacobus J.

2014-01-01

The genera Atta and Acromyrmex are often grouped as leaf-cutting ants for pest management assessments and ecological surveys, although their mature colony sizes and foraging niches may differ substantially. Few studies have addressed such interspecific differences at the same site, which prompted us to conduct a comparative study across six sympatric leaf-cutting ant species in Central Panama. We show that foraging rates during the transition between dry and wet season differ about 60 fold between genera, but are relatively constant across species within genera. These differences appear to match overall differences in colony size, especially when Atta workers that return to their nests without leaves are assumed to carry liquid food. We confirm that Panamanian Atta specialize primarily on tree-leaves whereas Acromyrmex focus on collecting flowers and herbal leaves and that species within genera are similar in these overall foraging strategies. Species within genera tended to be spaced out over the three habitat categories that we distinguished (forest, forest edge, open grassland), but each of these habitats normally had only a single predominant Atta and Acromyrmex species. We measured activities of twelve fungus garden decomposition enzymes, belonging to the amylases, cellulases, hemicellulases, pectinases and proteinases, and show that average enzyme activity per unit of fungal mass in Atta gardens is lower than in Acromyrmex gardens. Expression profiles of fungal enzymes in Atta also appeared to be more specialized than in Acromyrmex, possibly reflecting variation in forage material. Our results suggest that species- and genus-level identities of leaf-cutting ants and habitat-specific foraging profiles may give predictable differences in the expression of fungal genes coding for decomposition enzymes. PMID:24718261

Sheep numbers required for dry matter digestibility evaluations when fed fresh perennial ryegrass or forage rape.

PubMed

Sun, Xuezhao; Krijgsman, Linda; Waghorn, Garry C; Kjestrup, Holly; Koolaard, John; Pacheco, David

2017-03-01

Research trials with fresh forages often require accurate and precise measurement of digestibility and variation in digestion between individuals, and the duration of measurement periods needs to be established to ensure reliable data are obtained. The variation is likely to be greater when freshly harvested feeds are given, such as perennial ryegrass ( Lolium perenne L.) and forage rape ( Brassica napus L.), because the nutrient composition changes over time and in response to weather conditions. Daily feed intake and faeces output data from a digestibility trial with these forages were used to calculate the effects of differing lengths of the measurement period and differing numbers of sheep, on the precision of digestibility, with a view towards development of a protocol. Sixteen lambs aged 8 months and weighing 33 kg at the commencement of the trial were fed either perennial ryegrass or forage rape (8/treatment group) over 2 periods with 35 d between measurements. They had been acclimatised to the diets, having grazed them for 42 d prior to 11 days of indoor measurements. The sheep numbers required for a digestibility trial with different combinations of acclimatisation and measurement period lengths were subsequently calculated for 3 levels of imposed precision upon the estimate of mean dry matter (DM) digestibility. It is recommended that if the standard error of the mean for digestibility is equal to or higher than 5 g/kg DM, and if sheep are already used to a fresh perennial ryegrass or forage rape diet, then a minimum of 6 animals are needed and 4 acclimatisation days being fed individually in metabolic crates followed by 7 days of measurement.

Predator avoidance as a function of flocking in the sexually dichromatic Hawaii akepa

USGS Publications Warehouse

Hart, P.J.; Freed, L.A.

2005-01-01

Hypotheses for joining a mixed-species bird flock consider each species as a single unit. In sexually dichromatic birds, differential conspicuousness between the sexes may result in differences in vigilance for predators. Aspects of the predator avoidance and foraging enhancement hypotheses for the selective value of joining a mixed-species flock were assessed for the strongly sexually dichromatic Hawaii akepa (Loxops coccineus coccineus). There was support for the primary predictions of the predator avoidance hypothesis: vigilance levels decreased with increasing group size, and with membership in a flock, but only for brightly colored adult males. There was little support for the hypothesis that the primary benefit of joining a mixed-species flock is to enhance foraging efficiency through "local enhancement".

Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands.

PubMed

Loucougaray, Grégory; Dobremez, Laurent; Gos, Pierre; Pauthenet, Yves; Nettier, Baptiste; Lavorel, Sandra

2015-11-01

Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

Extreme mobility in the Late Pleistocene? Comparing limb biomechanics among fossil Homo, varsity athletes and Holocene foragers.

PubMed

Shaw, Colin N; Stock, Jay T

2013-04-01

Descriptions of Pleistocene activity patterns often derive from comparisons of long bone diaphyseal robusticity across contemporaneous fossilized hominins. The purpose of this study is to augment existing understanding of Pleistocene hominin mobility patterns by interpreting fossil variation through comparisons with a) living human athletes with known activity patterns, and b) Holocene foragers where descriptions of group-level activity patterns are available. Relative tibial rigidity (midshaft tibial rigidity (J)/midshaft humeral rigidity (J)) was compared amongst Levantine and European Neandertals, Levantine and Upper Palaeolithic Homo sapiens, Holocene foragers and living human athletes and controls. Cross-country runners exhibit significantly (p<0.05) greater relative tibial rigidity compared with swimmers, and higher values compared with controls. In contrast, swimmers displayed significantly (p<0.05) lower relative tibial rigidity than both runners and controls. While variation exists among all Holocene H. sapiens, highly terrestrially mobile Later Stone Age (LSA) southern Africans and cross-country runners display the highest relative tibial rigidity, while maritime Andaman Islanders and swimmers display the lowest, with controls falling between. All fossil hominins displayed relative tibial rigidity that exceeded, or was similar to, the highly terrestrially mobile Later Stone Age southern Africans and modern human cross-country runners. The more extreme skeletal structure of most Neandertals and Levantine H. sapiens, as well as the odd Upper Palaeolithic individual, appears to reflect adaptation to intense and/or highly repetitive lower limb (relative to upper limb) loading. This loading may have been associated with bipedal travel, and appears to have been more strenuous than that encountered by even university varsity runners, and Holocene foragers with hunting grounds 2000-3000 square miles in size. Skeletal variation among the athletes and foraging groups is consistent with known or inferred activity profiles, which support the position that the Pleistocene remains reflect adaptation to extremely active and mobile lives. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nectar Yeasts in the Tall Larkspur Delphinium barbeyi (Ranunculaceae) and Effects on Components of Pollinator Foraging Behavior

PubMed Central

Schaeffer, Robert N.; Phillips, Cody R.; Duryea, M. Catherine; Andicoechea, Jonathan; Irwin, Rebecca E.

2014-01-01

Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae) and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54–77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. Female-phase flowers of D. barbeyi were more likely to have higher densities of yeasts in comparison to male-phase flowers. Pollinators were likely vectors of yeasts, as virgin (unvisited) flowers rarely contained yeasts compared to flowers open to pollinator visitation, which were frequently colonized. Finally, pollinators responded positively to the presence of yeasts. Bombus foragers both visited and probed more flowers inoculated with yeasts in comparison to uninoculated controls. Taken together, our results suggest that variation in the occurrence and density of nectar-inhabiting yeasts have the potential to alter components of pollinator foraging behavior linked to pollen transfer and plant fitness. PMID:25272164

[Application of near infrared spectroscopy technology (NIRS) in forage field].

PubMed

Yan, Xu; Bai, Shi-Qie; Yan, Jia-Jun; Gan, You-Min; Dao, Zhi-Xue

2012-07-01

The majority of nutrients in ruminants and other herbivores come from forages. Forage quality not only affects the growth and production efficiency of livestock, but also determines the final output and quality of livestock products. Forage quality mainly depends on nutrient concentrations and their digestibility, palatability and the level of presence of antiquality factors and mycotoxins in forage. Near infrared reflectance spectroscopy (NIRS) has been widely used in many research areas because it is a inexpensive, rapid, simple and nondestructive technique offering the potential for qualitative and quantitative analysis. The present paper briefly introduces the principle and characteristics of NIRS, detailedly expounds the application of NIRS in forage quality. In addition, other applications of near infrared spectroscopy technique in forage are also discussed, including forage breeding, identification of variety and classification by kind. This paper comprehensively reviews the status quo of application of NIRS in forage filed, in order to contribute to promoting development of NIRS in this field in China.

Variability in individual activity bursts improves ant foraging success.

PubMed

Campos, Daniel; Bartumeus, Frederic; Méndez, Vicenç; Andrade, José S; Espadaler, Xavier

2016-12-01

Using experimental and computational methods, we study the role of behavioural variability in activity bursts (or temporal activity patterns) for individual and collective regulation of foraging in A. senilis ants. First, foraging experiments were carried out under special conditions (low densities of ants and food and absence of external cues or stimuli) where individual-based strategies are most prevalent. By using marked individuals and recording all foraging trajectories, we were then able to precisely quantify behavioural variability among individuals. Our main conclusions are that (i) variability of ant trajectories (turning angles, speed, etc.) is low compared with variability of temporal activity profiles, and (ii) this variability seems to be driven by plasticity of individual behaviour through time, rather than the presence of fixed behavioural stereotypes or specialists within the group. The statistical measures obtained from these experimental foraging patterns are then used to build a general agent-based model (ABM) which includes the most relevant properties of ant foraging under natural conditions, including recruitment through pheromone communication. Using the ABM, we are able to provide computational evidence that the characteristics of individual variability observed in our experiments can provide a functional advantage (in terms of foraging success) to the group; thus, we propose the biological basis underpinning our observations. Altogether, our study reveals the potential utility of experiments under simplified (laboratory) conditions for understanding information-gathering in biological systems. © 2016 The Author(s).

Effects of corn straw or mixed forage diet on rumen fermentation parameters of lactating cows using a wireless data logger.

PubMed

Qin, Chunfu; Bu, Dengpan; Sun, Peng; Zhao, Xiaowei; Zhang, Peihua; Wang, Jiaqi

2017-02-01

The objective of this study was to evaluate the effect of two different forage types on rumen fermentation parameters and profiles using a wireless data logger. Eight lactating cows were randomly assigned to one of two dietary treatments with a low forage diet with corn straw (CS) or a high forage diet with mixed forage (MF) as the forage source, respectively. Dietary physically effective neutral detergent fiber (peNDF) content was 11.3% greater in CS. Dry matter intake and milk fatty acid content decreased upon CS (P < 0.05). Ruminal pH, temperature and oxidation reduction potential (ORP) were monitored for 14 weeks. The CS group had significantly higher pH but lower temperature and ORP compared to MF (P < 0.01). With the CS diet regime, pH at the time before morning feeding, rumination and post-ingestion were significantly higher than those in the MF group (P < 0.05). However, times with the ruminal pH below 6.0 and 5.8 were significantly reduced (P < 0.05), whereas ruminal pH below 5.6 tended to be lower (P = 0.07). The results indicated that rumen fermentation parameters were affected by forage types and dietary peNDF content might be predominant in ruminal pH regulation. © 2016 Japanese Society of Animal Science.

Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins.

PubMed

Ji, Cuiying; Zhang, Xuewei; Yu, Peiqiang

2016-03-05

The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653 cm(-1) and 1545 cm(-1), respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of delignification upon in vitro digestion of forage cellulose.

PubMed

Darcy, B K; Belyea, R L

1980-10-01

Orchardgrass forages harvested at two maturities (early and late) were ground through two screens (1 and 8 mm) and digested in vitro as intact forage and forage delignified by permanganate oxidation. Initial and residual cell wall, initial and residual cellulose and potentially digestible cellulose were greater in late intact forage than in the early. In the delignified forage, late cut forage had less residual cellulose than did the early, but initial and potentially digestible cellulose were similar. Particle size had less consistent and smaller effects upon cell wall and cellulose than did maturity. Cellulose of intact orchardgrass was 64% digested at 72 h vs 94% for cellulose of delignified orchardgrass. Digestion rate of cellulose was .0197 and .0220 logn units/hr for early and late cut intact forage and .0554 and .0719 logn units/hr for early and late cut delignified forage. Removal of the inhibitory effects of lignin increased the amount of digestible cellulose, increased the rate at which cellulose degraded and decreased the indigestible cellulose residue. Reduction in lignin could greatly improve forage intake and utilization at moderate levels of animal production.

Early Visual Foraging in Relationship to Familial Risk for Autism and Hyperactivity/Inattention.

PubMed

Gliga, Teodora; Smith, Tim J; Likely, Noreen; Charman, Tony; Johnson, Mark H

2015-12-04

Information foraging is atypical in both autism spectrum disorders (ASDs) and ADHD; however, while ASD is associated with restricted exploration and preference for sameness, ADHD is characterized by hyperactivity and increased novelty seeking. Here, we ask whether similar biases are present in visual foraging in younger siblings of children with a diagnosis of ASD with or without additional high levels of hyperactivity and inattention. Fifty-four low-risk controls (LR) and 50 high-risk siblings (HR) took part in an eye-tracking study at 8 and 14 months and at 3 years of age. At 8 months, siblings of children with ASD and low levels of hyperactivity/inattention (HR/ASD-HI) were more likely to return to previously visited areas in the visual scene than were LR and siblings of children with ASD and high levels of hyperactivity/inattention (HR/ASD+HI). We show that visual foraging is atypical in infants at-risk for ASD. We also reveal a paradoxical effect, in that additional family risk for ADHD core symptoms mitigates the effect of ASD risk on visual information foraging. © The Author(s) 2015.

Baseline glucose level is an individual trait that is negatively associated with lifespan and increases due to adverse environmental conditions during development and adulthood.

PubMed

Montoya, Bibiana; Briga, Michael; Jimeno, Blanca; Moonen, Sander; Verhulst, Simon

2018-05-01

High baseline glucose levels are associated with pathologies and shorter lifespan in humans, but little is known about causes and consequences of individual variation in glucose levels in other species. We tested to what extent baseline blood glucose level is a repeatable trait in adult zebra finches, and whether glucose levels were associated with age, manipulated environmental conditions during development (rearing brood size) and adulthood (foraging cost), and lifespan. We found that: (1) repeatability of glucose levels was 30%, both within and between years. (2) Having been reared in a large brood and living with higher foraging costs as adult were independently associated with higher glucose levels. Furthermore, the finding that baseline glucose was low when ambient temperature was high, and foraging costs were low, indicates that glucose is regulated at a lower level when energy turnover is low. (3) Survival probability decreased with increasing baseline glucose. We conclude that baseline glucose is an individual trait negatively associated with survival, and increases due to adverse environmental conditions during development (rearing brood size) and adulthood (foraging cost). Blood glucose may be, therefore, part of the physiological processes linking environmental conditions to lifespan.

The Mechanisms of Water Exchange: The Regulatory Roles of Multiple Interactions in Social Wasps.

PubMed

Agrawal, Devanshu; Karsai, Istvan

2016-01-01

Evolutionary benefits of task fidelity and improving information acquisition via multiple transfers of materials between individuals in a task partitioned system have been shown before, but in this paper we provide a mechanistic explanation of these phenomena. Using a simple mathematical model describing the individual interactions of the wasps, we explain the functioning of the common stomach, an information center, which governs construction behavior and task change. Our central hypothesis is a symmetry between foragers who deposit water and foragers who withdraw water into and out of the common stomach. We combine this with a trade-off between acceptance and resistance to water transfer. We ultimately derive a mathematical function that relates the number of interactions that foragers complete with common stomach wasps during a foraging cycle. We use field data and additional model assumptions to calculate values of our model parameters, and we use these to explain why the fullness of the common stomach stabilizes just below 50 percent, why the average number of successful interactions between foragers and the wasps forming the common stomach is between 5 and 7, and why there is a variation in this number of interactions over time. Our explanation is that our proposed water exchange mechanism places natural bounds on the number of successful interactions possible, water exchange is set to optimize mediation of water through the common stomach, and the chance that foragers abort their task prematurely is very low.

Nutrient-mediated architectural plasticity of a predatory trap.

PubMed

Blamires, Sean J; Tso, I-Min

2013-01-01

Nutrients such as protein may be actively sought by foraging animals. Many predators exhibit foraging plasticity, but how their foraging strategies are affected when faced with nutrient deprivation is largely unknown. In spiders, the assimilation of protein into silk may be in conflict with somatic processes so we predicted web building to be affected under protein depletion. To assess the influence of protein intake on foraging plasticity we fed the orb-web spiders Argiope aemula and Cyclosa mulmeinensis high, low or no protein solutions over 10 days and allowed them to build webs. We compared post-feeding web architectural components and major ampullate (MA) silk amino acid compositions. We found that the number of radii in webs increased in both species when fed high protein solutions. Mesh size increased in A. aemula when fed a high protein solution. MA silk proline and alanine compositions varied in each species with contrasting variations in alanine between the two species. Glycine compositions only varied in C. mulmeinensis silk. No spiders significantly lost or gained mass on any feeding treatment, so they did not sacrifice somatic maintenance for amino acid investment in silk. Our results show that the amount of protein taken in significantly affects the foraging decisions of trap-building predators, such as orb web spiders. Nevertheless, the subtle differences found between species in the association between protein intake, the amino acids invested in silk and web architectural plasticity show that the influence of protein deprivation on specific foraging strategies differs among different spiders.

The Mechanisms of Water Exchange: The Regulatory Roles of Multiple Interactions in Social Wasps

PubMed Central

Agrawal, Devanshu; Karsai, Istvan

2016-01-01

Evolutionary benefits of task fidelity and improving information acquisition via multiple transfers of materials between individuals in a task partitioned system have been shown before, but in this paper we provide a mechanistic explanation of these phenomena. Using a simple mathematical model describing the individual interactions of the wasps, we explain the functioning of the common stomach, an information center, which governs construction behavior and task change. Our central hypothesis is a symmetry between foragers who deposit water and foragers who withdraw water into and out of the common stomach. We combine this with a trade-off between acceptance and resistance to water transfer. We ultimately derive a mathematical function that relates the number of interactions that foragers complete with common stomach wasps during a foraging cycle. We use field data and additional model assumptions to calculate values of our model parameters, and we use these to explain why the fullness of the common stomach stabilizes just below 50 percent, why the average number of successful interactions between foragers and the wasps forming the common stomach is between 5 and 7, and why there is a variation in this number of interactions over time. Our explanation is that our proposed water exchange mechanism places natural bounds on the number of successful interactions possible, water exchange is set to optimize mediation of water through the common stomach, and the chance that foragers abort their task prematurely is very low. PMID:26751076

Effects of water level changes and wading bird abundance on the foraging behaviour of blacknecked storks Ephippiorhynchus asiaticus in Dudwa National Park, India.

PubMed

Maheswaran, G; Rahmani, A R

2001-09-01

The effect of water level changes and wading birds' abundance on the foraging behaviour of the blacknecked stork (BNS) Ephippiorhynchus asiaticus was studied from January 1995 to June 1997 in Dudwa National Park, Uttar Pradesh. Our observations indicate that BNS territoriality increased as food levels became depleted, resulting in increased rates of aggression towards intruders. Chasing or aggression was more intense during the early period (February and March) than the late period (April, May and June). Most of (> 50%) the aggressive encounters were observed between 0600 and 1000 h of the day. Seventeen species (including BNS) were observed interacting with BNS, throughout the study period. Most interactions were with the spoonbill, Platalea leucorodia (67.4%), followed by the whitenecked stork, Ciconia episcopus (16.6%). The distance (while foraging) between BNS and other wading birds varied significantly (P < 0.001) between years indicating that BNS and other water birds foraged at different water depths and thereby explored the wetlands fully. Spoonbills were chased often; the number varied from 1 to 43 birds. BNS occasionally accepted the presence of other wading birds, including spoonbills and started foraging amidst them. This led to successful foraging of BNS (solitary feeder). Other fish-eating bird species and their numbers also limited the food consumption of foraging BNS as they had to spend time chasing away the intruders. Availability of the preferred prey fish species, Heteropnestus fossilis, forced BNS to stay throughout the year in their respective territories. High (> 60 cm) water levels were not suitable for BNS even though the patch had high prey abundance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safira, Nabila, E-mail: safira.nabila@ymail.com; Anggraeni, Tjandra, E-mail: tjandra@sith.itb.ac.id

Several studies had shown that lead (Pb) in the environment could accumulate in bees, which in turn could affect the quality of the resulting product. In this study, forager stingless bees (Trigona sp.) and its product (propolis) collected from a stingless bees apiculture. This apiculture had two apiary sites which were distinguished by its environmental setting. Apiary site in Cilutung had a forest region environmental setting, while apiary site in Maribaya was located beside the main road. The objective of this study was to determine the extent of lead concentration in propolis originated from both apiary sites and establish themore » correlation between lead concentration in propolis and lead level in forager stingless bees. Forager bees and propolis samples were originated from 50 bees colonies (Cilutung) and 44 bees colonies (Maribaya). They were analyzed using AAS-GF (Atomic Absorption Spectrometre–Graphite Furnace) to determine the level of lead concentration. The results showed that the average level of lead in propolis originated from Cilutung (298.08±73.71 ppb) was lower than the average level of lead in forager bees which originated from Maribaya (330.64±156.34 ppb). However, these values did not show significant difference (p>0.05). There was no significant difference (p>0.05) between the average level of lead in forager bees which originated from Cilutung (118.08±30.46 ppb) and Maribaya (128.82±39.66 ppb). However, these values did not show significant difference (p>0.05). In conclusion, the average level of lead concentration in propolis in both sites had passed the maximum permission standard of lead for food in Indonesia. There was no correlation between lead concentration in propolis and forager stingless bees.« less

Sensory response system of social behavior tied to female reproductive traits.

PubMed

Tsuruda, Jennifer M; Amdam, Gro V; Page, Robert E

2008-01-01

Honey bees display a complex set of anatomical, physiological, and behavioral traits that correlate with the colony storage of surplus pollen (pollen hoarding). We hypothesize that the association of these traits is a result of pleiotropy in a gene signaling network that was co-opted by natural selection to function in worker division of labor and foraging specialization. By acting on the gene network, selection can change a suite of traits, including stimulus/response relationships that affect individual foraging behavior and alter the colony level trait of pollen hoarding. The 'pollen-hoarding syndrome' of honey bees is the best documented syndrome of insect social organization. It can be exemplified as a link between reproductive anatomy (ovary size), physiology (yolk protein level), and foraging behavior in honey bee strains selected for pollen hoarding, a colony level trait. The syndrome gave rise to the forager-Reproductive Ground Plan Hypothesis (RGPH), which proposes that the regulatory control of foraging onset and foraging preference toward nectar or pollen was derived from a reproductive signaling network. This view was recently challenged. To resolve the controversy, we tested the associations between reproductive anatomy, physiology, and stimulus/response relationships of behavior in wild-type honey bees. Central to the stimulus/response relationships of honey bee foraging behavior and pollen hoarding is the behavioral trait of sensory sensitivity to sucrose (an important sugar in nectar). To test the linkage of reproductive traits and sensory response systems of social behavior, we measured sucrose responsiveness with the proboscis extension response (PER) assay and quantified ovary size and vitellogenin (yolk precursor) gene expression in 6-7-day-old bees by counting ovarioles (ovary filaments) and by using semiquantitative real time RT-PCR. We show that bees with larger ovaries (more ovarioles) are characterized by higher levels of vitellogenin mRNA expression and are more responsive to sucrose solutions, a trait that is central to division of labor and foraging specialization. Our results establish that in wild-type honey bees, ovary size and vitellogenin mRNA level covary with the sucrose sensory response system, an important component of foraging behavior. This finding validates links between reproductive physiology and behavioral-trait associations of the pollen-hoarding syndrome of honey bees, and supports the forager-RGPH. Our data address a current evolutionary debate, and represent the first direct demonstration of the links between reproductive anatomy, physiology, and behavioral response systems that are central to the control of complex social behavior in insects.

Acetone Enhances the Direct Analysis of Total Condensed Tannins in Forage Legumes by the Butanol-HCl Assay

USDA-ARS?s Scientific Manuscript database

Depending on concentration, condensed tannins (CT) in forages have no effect, enhance, or impede protein utilization and performance of ruminants. Defining optimal forage CT levels has been elusive, partly because current methods for estimating total soluble plus insoluble CT are laborious or inaccu...

Influence of protein type and level on nitrogen and forage utilization in cows consuming low-quality forage

USDA-ARS?s Scientific Manuscript database

Minimal quantities of ruminally degradable protein from supplements may improve supplement utilization efficiency of ruminants grazing dormant forages. In Exp. 1, N retention, ruminal NH3, serum urea N, and NDF digestibility was evaluated for 12 ruminally cannulated cows in an incomplete Latin Squa...

Comparative proteomic analysis of alfalfa revealed new salt and drought stress-related factors involved in seed germination.

PubMed

Ma, Qiaoli; Kang, Junmei; Long, Ruicai; Zhang, Tiejun; Xiong, Junbo; Zhang, Kun; Wang, Tenghua; Yang, Qingchuan; Sun, Yan

2017-07-01

Salinity and drought are two major environmental factors that limit the growth and yield of many forage crops in semi-arid and arid regions. Alfalfa (Medicago sativa L.) is one of the most important forage crops in many countries. We aim to investigate the molecular mechanisms of alfalfa in response to salt and drought stresses in this study. Physiological and proteomic analyses were applied to examine the Zhongmu NO.3 alfalfa seed germination stage with 200 mM NaCl and 180 g·L -1 polyethylene glycol (PEG) treatments. The germination ability of the seed and the accumulation of osmotic solutes were quite different between the NaCl and PEG treatments. More than 800 protein spots were detected by proteomics technology on two-dimensional electrophoresis (2-DE) gels. The abundance of twenty-eight proteins were decreased or increased after salt and drought stress. Seventeen of these proteins were identified and classified into six functional categories through mass spectrometry (MS). The six groups involved in salt- and PEG-mediated stress included defense response, energy metabolism, protein synthesis and degradation, oxidative stress, carbohydrate metabolism-associated proteins, and unknown proteins. We discovered that some proteins related to carbohydrate metabolism and energy production increased in abundance under salt- and PEG-mediated drought stress. This demonstrates a common mechanism of energy consumption during abiotic stresses. Further study of these proteins with unknown function will provide insights into the molecular mechanisms of abiotic stress and the discovery of new candidate markers.

[Occurrence and behavioral patterns of the spotted coastal dolphin Stenella attenuata (Cetacea: delphinidae) in the Gulf of Papagayo, Costa Rica].

PubMed

May-Collado, Laura; Ramírez, Alvaro Morales

2005-01-01

Dolphins are characterized by a significant behavioral versatility, which allows them to respond to environmental seasonality. Seasonal variation in dolphin behavior in tropical waters is not well known. Stenella attenuata graffmani is a resident dolphin in the clearly defined seasonal Gulf of Papagayo, Costa Rica, and we studied if dolphin group size, occurrence and behavioral patterns were associated with season and time of day in the gulf. Using strip transects we surveyed two locations for three consecutive years. School size ranged from 1 to 50 individuals, mean group size was 10.16 (SD = 9.61) individuals. Overall, foraging activities were the most frequent, followed by social interactions and travel. From 6:00 AM to 9:00 AM we mostly observed social interactions, followed by feeding-socializing (9:00 AM-12:00 PM) and feeding exclusively (12:00 PM-3:00 PM). Social activities intensified afterwards (3:00 PM-6:00 PM). Behavior and gulf seasonality were associated (chi2 = 90.52, gl = 6, p<0.05, n = 99). In the dry season (December-April) feeding predominated over other activities, but socializing was more frequent in the early rainy season (May-July). Larger groups (mean 12 dolphins) forage actively; smaller groups (mean 6 dolphins 6.51 +/- 5.12) foraged more passively. Seasonal variation in dolphin activities are likely to be associated with food availability, as observed in the high number of groups involved in foraging behaviors, and a high investment in foraging activities during the dry season.

Chromatic signals control proboscis movements during hovering flight in the hummingbird hawkmoth Macroglossum stellatarum.

PubMed

Goyret, Joaquín; Kelber, Almut

2012-01-01

Most visual systems are more sensitive to luminance than to colour signals. Animals resolve finer spatial detail and temporal changes through achromatic signals than through chromatic ones. Probably, this explains that detection of small, distant, or moving objects is typically mediated through achromatic signals. Macroglossum stellatarum are fast flying nectarivorous hawkmoths that inspect flowers with their long proboscis while hovering. They can visually control this behaviour using floral markings known as nectar guides. Here, we investigate whether this is mediated by chromatic or achromatic cues. We evaluated proboscis placement, foraging efficiency, and inspection learning of naïve moths foraging on flower models with coloured markings that offered either chromatic, achromatic or both contrasts. Hummingbird hawkmoths could use either achromatic or chromatic signals to inspect models while hovering. We identified three, apparently independent, components controlling proboscis placement: After initial contact, 1) moths directed their probing towards the yellow colour irrespectively of luminance signals, suggesting a dominant role of chromatic signals; and 2) moths tended to probe mainly on the brighter areas of models that offered only achromatic signals. 3) During the establishment of the first contact, naïve moths showed a tendency to direct their proboscis towards the small floral marks independent of their colour or luminance. Moths learned to find nectar faster, but their foraging efficiency depended on the flower model they foraged on. Our results imply that M. stellatarum can perceive small patterns through colour vision. We discuss how the different informational contents of chromatic and luminance signals can be significant for the control of flower inspection, and visually guided behaviours in general.

The role of ecological factors in shaping bat cone opsin evolution.

PubMed

Gutierrez, Eduardo de A; Schott, Ryan K; Preston, Matthew W; Loureiro, Lívia O; Lim, Burton K; Chang, Belinda S W

2018-04-11

Bats represent one of the largest and most striking nocturnal mammalian radiations, exhibiting many visual system specializations for performance in light-limited environments. Despite representing the greatest ecological diversity and species richness in Chiroptera, Neotropical lineages have been undersampled in molecular studies, limiting the potential for identifying signatures of selection on visual genes associated with differences in bat ecology. Here, we investigated how diverse ecological pressures mediate long-term shifts in selection upon long-wavelength ( Lws ) and short-wavelength ( Sws1 ) opsins, photosensitive cone pigments that form the basis of colour vision in most mammals, including bats. We used codon-based likelihood clade models to test whether ecological variables associated with reliance on visual information (e.g. echolocation ability and diet) or exposure to varying light environments (e.g. roosting behaviour and foraging habitat) mediated shifts in evolutionary rates in bat cone opsin genes. Using additional cone opsin sequences from newly sequenced eye transcriptomes of six Neotropical bat species, we found significant evidence for different ecological pressures influencing the evolution of the cone opsins. While Lws is evolving under significantly lower constraint in highly specialized high-duty cycle echolocating lineages, which have enhanced sonar ability to detect and track targets, variation in Sws1 constraint was significantly associated with foraging habitat, exhibiting elevated rates of evolution in species that forage among vegetation. This suggests that increased reliance on echolocation as well as the spectral environment experienced by foraging bats may differentially influence the evolution of different cone opsins. Our study demonstrates that different ecological variables may underlie contrasting evolutionary patterns in bat visual opsins, and highlights the suitability of clade models for testing ecological hypotheses of visual evolution. © 2018 The Author(s).

40 CFR 180.434 - Propiconazole; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., leaves 13 Citrus, oil 1000 Corn, field, forage 12 Corn, field, grain 0.2 Corn, field, stover 30 Corn, pop, grain 0.2 Corn, pop, stover 30 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 30 Fruit, citrus, group 10-10 8.0 Fruit, stone, group 12, except plum 4.0 Goat...

40 CFR 180.434 - Propiconazole; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., leaves 13 Citrus, oil 1000 Corn, field, forage 12 Corn, field, grain 0.2 Corn, field, stover 30 Corn, pop, grain 0.2 Corn, pop, stover 30 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 30 Fruit, citrus, group 10-10 8.0 Fruit, stone, group 12, except plum 4.0 Goat...

40 CFR 180.478 - Rimsulfuron; tolerances for residues

Code of Federal Regulations, 2010 CFR

2010-07-01

... the commodities. Commodity Parts per million Almond, hulls 0.09 Corn, field, forage 0.4 Corn, field, grain 0.1 Corn, field, stover 2.5 Fruit, citrus, group 10 0.01 Fruit, pome, group 11 0.01 Fruit, stone....1 Soybean, forage 0.25 Soybean, hay 1.2 Soybean, hulls 0.04 Soybean, seed 0.01 Tomato 0.05 (b...

Benefits of Group Foraging Depend on Prey Type in a Small Marine Predator, the Little Penguin.

PubMed

Sutton, Grace J; Hoskins, Andrew J; Arnould, John P Y

2015-01-01

Group foraging provides predators with advantages in over-powering prey larger than themselves or in aggregating small prey for efficient exploitation. For group-living predatory species, cooperative hunting strategies provide inclusive fitness benefits. However, for colonial-breeding predators, the benefit pay-offs of group foraging are less clear due to the potential for intra-specific competition. We used animal-borne cameras to determine the prey types, hunting strategies, and success of little penguins (Eudyptula minor), a small, colonial breeding air-breathing marine predator that has recently been shown to display extensive at-sea foraging associations with conspecifics. Regardless of prey type, little penguins had a higher probability of associating with conspecifics when hunting prey that were aggregated than when prey were solitary. In addition, success was greater when individuals hunted schooling rather than solitary prey. Surprisingly, however, success on schooling prey was similar or greater when individuals hunted on their own than when with conspecifics. These findings suggest individuals may be trading-off the energetic gains of solitary hunting for an increased probability of detecting prey within a spatially and temporally variable prey field by associating with conspecifics.

Risk of predation makes foragers less choosy about their food.

PubMed

Charalabidis, Alice; Dechaume-Moncharmont, François-Xavier; Petit, Sandrine; Bohan, David A

2017-01-01

Animals foraging in the wild have to balance speed of decision making and accuracy of assessment of a food item's quality. If resource quality is important for maximizing fitness, then the duration of decision making may be in conflict with other crucial and time consuming tasks, such as anti-predator behaviours or competition monitoring. Individuals facing the risk of predation and/or competition should adjust the duration of decision making and, as a consequence, their level of choosiness for resources. When exposed to predation, the forager could either maintain its level of choosiness for food items but accept a reduction in the amount of food items consumed or it could reduce its level of choosiness and accept all prey items encountered. Under competition risk, individuals are expected to reduce their level of choosiness as slow decision making exposes individuals to a higher risk of opportunity costs. To test these predictions, the level of choosiness of a seed-eating carabid beetle, Harpalus affinis, was examined under 4 different experimental conditions of risk: i) predation risk; ii) intraspecific competition; iii) interspecific competition; and, iv) control. All the risks were simulated using chemical cues from individual conspecifics or beetles of different species that are predatory or granivorous. Our results show that when foraging under the risk of predation, H. affinis individuals significantly reduce their level of choosiness for seeds. Reductions in level of choosiness for food items might serve as a sensible strategy to reduce both the total duration of a foraging task and the cognitive load of the food quality assessment. No significant differences were observed when individuals were exposed to competition cues. Competition, (i.e opportunity cost) may not be perceived as risk high enough to induce changes in the level of choosiness. Our results suggest that considering the amount of items consumed, alone, would be a misleading metric when assessing individual response to a risk of predation. Foraging studies should therefore also take in account the decision making process.

Humans Strengthen Bottom-Up Effects and Weaken Trophic Cascades in a Terrestrial Food Web

PubMed Central

Muhly, Tyler B.; Hebblewhite, Mark; Paton, Dale; Pitt, Justin A.; Boyce, Mark S.; Musiani, Marco

2013-01-01

Ongoing debate about whether food webs are primarily regulated by predators or by primary plant productivity, cast as top-down and bottom-up effects, respectively, may becoming superfluous. Given that most of the world's ecosystems are human dominated we broadened this dichotomy by considering human effects in a terrestrial food-web. We studied a multiple human-use landscape in southwest Alberta, Canada, as opposed to protected areas where previous terrestrial food-web studies have been conducted. We used structural equation models (SEMs) to assess the strength and direction of relationships between the density and distribution of: (1) humans, measured using a density index; (2) wolves (Canis lupus), elk (Cervus elpahus) and domestic cattle (Bos taurus), measured using resource selection functions, and; (3) forage quality, quantity and utilization (measured at vegetation sampling plots). Relationships were evaluated by taking advantage of temporal and spatial variation in human density, including day versus night, and two landscapes with the highest and lowest human density in the study area. Here we show that forage-mediated effects of humans had primacy over predator-mediated effects in the food web. In our parsimonious SEM, occurrence of humans was most correlated with occurrence of forage (β = 0.637, p<0.0001). Elk and cattle distribution were correlated with forage (elk day: β = 0.400, p<0.0001; elk night: β = 0.369, p<0.0001; cattle day: β = 0.403, p<0.0001; cattle, night: β = 0.436, p<0.0001), and the distribution of elk or cattle and wolves were positively correlated during daytime (elk: β = 0.293, p <0.0001, cattle: β = 0.303, p<0.0001) and nighttime (elk: β = 0.460, p<0.0001, cattle: β = 0.482, p<0.0001). Our results contrast with research conducted in protected areas that suggested human effects in the food web are primarily predator-mediated. Instead, human influence on vegetation may strengthen bottom-up predominance and weaken top-down trophic cascades in ecosystems. We suggest that human influences on ecosystems may usurp top-down and bottom-up effects. PMID:23667705

Male group size, female distribution and changes in sexual segregation by Roosevelt elk

PubMed Central

Peterson, Leah M.

2017-01-01

Sexual segregation, or the differential use of space by males and females, is hypothesized to be a function of body size dimorphism. Sexual segregation can also manifest at small (social segregation) and large (habitat segregation) spatial scales for a variety of reasons. Furthermore, the connection between small- and large-scale sexual segregation has rarely been addressed. We studied a population of Roosevelt elk (Cervus elaphus roosevelti) across 21 years in north coastal California, USA, to assess small- and large-scale sexual segregation in winter. We hypothesized that male group size would associate with small-scale segregation and that a change in female distribution would associate with large-scale segregation. Variation in forage biomass might also be coupled to small and large-scale sexual segregation. Our findings were consistent with male group size associating with small-scale segregation and a change in female distribution associating with large-scale segregation. Females appeared to avoid large groups comprised of socially dominant males. Males appeared to occupy a habitat vacated by females because of a wider forage niche, greater tolerance to lethal risks, and, perhaps, to reduce encounters with other elk. Sexual segregation at both spatial scales was a poor predictor of forage biomass. Size dimorphism was coupled to change in sexual segregation at small and large spatial scales. Small scale segregation can seemingly manifest when all forage habitat is occupied by females and large scale segregation might happen when some forage habitat is not occupied by females. PMID:29121076

Biosynthesis of hydroxycinnamoyl esters and amides in legume species

USDA-ARS?s Scientific Manuscript database

In forage crops, protein that is degraded following harvest is poorly utilized by ruminant animals, resulting in both economic and environmental consequences. In red clover, secondary reactions of quinones resulting from polyphenol oxidase (PPO)-mediated oxidation of the caffeic acid derivatives pha...

A Unique Assemblage of Engraved Plaquettes from Ein Qashish South, Jezreel Valley, Israel: Figurative and Non-Figurative Symbols of Late Pleistocene Hunters-Gatherers in the Levant

PubMed Central

Yaroshevich, Alla; Bar-Yosef, Ofer; Boaretto, Elisabeta; Caracuta, Valentina; Greenbaum, Noam; Porat, Naomi; Roskin, Joel

2016-01-01

Three engraved limestone plaquettes from the recently excavated Epipaleolithic open-air site Ein Qashish South in the Jezreel Valley, Israel comprise unique evidence for symbolic behavior of Late Pleistocene foragers in the Levant. The engravings, uncovered in Kebaran and Geometric Kebaran deposits (ca. 23ka and ca. 16.5ka BP), include the image of a bird—the first figurative representation known so far from a pre-Natufian Epipaleolithic—along with geometric motifs such as chevrons, crosshatchings and ladders. Some of the engravings closely resemble roughly contemporary European finds interpreted as "systems of notations" or "artificial memory systems"–records related to timing of seasonal resources and associated aggregation events of nomadic groups. Moreover, similarly looking signs and patterns are well known from the context of the local Natufian—a final Epipaleolithic culture of sedentary or semi-sedentary foragers who started practicing agriculture. The investigation of the engravings found in Ein Qashish South involves conceptualizations developed in studies of European and local parallels, a selection of ethnographic examples and preliminary microscopic observations of the plaquettes. This shows that the figurative and non-figurative images comprise a coherent assemblage of symbols that might have been applied in order to store, share and transmit information related to social and subsistence realms of mobile bands. It further suggests that the site functioned as a locality of groups' aggregation and indicates social complexity of pre-Natufian foragers in the Levant. While alterations in social and subsistence strategies can explain the varying frequency of image use characterizing different areas of the Late Pleistocene world—the apparent similarity in graphics and the mode of their application support the possibility that symbol-mediated behavior has a common and much earlier origin. PMID:27557110

Resource diversity and landscape-level homogeneity drive native bee foraging.

PubMed

Jha, Shalene; Kremen, Claire

2013-01-08

Given widespread declines in pollinator communities and increasing global reliance on pollinator-dependent crops, there is an acute need to develop a mechanistic understanding of native pollinator population and foraging biology. Using a population genetics approach, we determine the impact of habitat and floral resource distributions on nesting and foraging patterns of a critical native pollinator, Bombus vosnesenskii. Our findings demonstrate that native bee foraging is far more plastic and extensive than previously believed and does not follow a simple optimal foraging strategy. Rather, bumble bees forage further in pursuit of species-rich floral patches and in landscapes where patch-to-patch variation in floral resources is less, regardless of habitat composition. Thus, our results reveal extreme foraging plasticity and demonstrate that floral diversity, not density, drives bee foraging distance. Furthermore, we find a negative impact of paved habitat and a positive impact of natural woodland on bumble bee nesting densities. Overall, this study reveals that natural and human-altered landscapes can be managed for increased native bee nesting and extended foraging, dually enhancing biodiversity and the spatial extent of pollination services.

Behavioral Effects of an Enhanced Enrichment Program for Group-Housed Sooty Mangabeys (Cercocebus atys)

PubMed Central

Crast, Jessica; Bloomsmith, Mollie A; Jonesteller, Trina J

2016-01-01

Evaluating the behavioral effects of enrichment on animals housed in biomedical facilities is necessary to effectively support their care and wellbeing. We tested the cumulative effects of an enhanced enrichment program on sooty mangabey behavior: locomotion, feeding and foraging, manipulating items in the enclosure, social affiliation, aggression, and abnormal behavior. The enhanced enrichment program included the addition of a substrate (timothy hay), widely distributing small pieces of produce and a forage mixture in the hay, adding structures and perching, and increasing the variety of food items, foraging devices, and other manipulable items. We tested 10 groups living in runs (n = 54) by using an ABA experimental design (phase A, standard enrichment; phase B, enhanced enrichment) and Wilcoxon signed-rank tests to compare behavior across phases. During phase B, subjects significantly increased feeding, foraging, and manipulation of items, and they decreased self-grooming, social affiliation, and aggression. Combined enrichment use increased from approximately 10% to 21% of the mangabeys’ time. Enhanced enrichment did not affect locomotion or abnormal behavior. The increases in feeding, foraging, and manipulation during enhanced enrichment were driven primarily by the subjects’ preference for foraging in the hay: it was the most effective component of the program in promoting feeding and foraging behavior, which comprises the majority of wild sooty mangabeys’ daily activity. Developing an effective, species-appropriate, and comprehensive enrichment program is essential to successfully promote the health and wellbeing of captive NHP. PMID:27931313

Behavioral Effects of an Enhanced Enrichment Program for Group-Housed Sooty Mangabeys (Cercocebus atys).

PubMed

Crast, Jessica; Bloomsmith, Mollie A; Jonesteller, Trina J

2016-11-01

Evaluating the behavioral effects of enrichment on animals housed in biomedical facilities is necessary to effectively support their care and wellbeing. We tested the cumulative effects of an enhanced enrichment program on sooty mangabey behavior: locomotion, feeding and foraging, manipulating items in the enclosure, social affiliation, aggression, and abnormal behavior. The enhanced enrichment program included the addition of a substrate (timothy hay), widely distributing small pieces of produce and a forage mixture in the hay, adding structures and perching, and increasing the variety of food items, foraging devices, and other manipulable items. We tested 10 groups living in runs (n = 54) by using an ABA experimental design (phase A, standard enrichment; phase B, enhanced enrichment) and Wilcoxon signed-rank tests to compare behavior across phases. During phase B, subjects significantly increased feeding, foraging, and manipulation of items, and they decreased self-grooming, social affiliation, and aggression. Combined enrichment use increased from approximately 10% to 21% of the mangabeys' time. Enhanced enrichment did not affect locomotion or abnormal behavior. The increases in feeding, foraging, and manipulation during enhanced enrichment were driven primarily by the subjects' preference for foraging in the hay: it was the most effective component of the program in promoting feeding and foraging behavior, which comprises the majority of wild sooty mangabeys' daily activity. Developing an effective, species-appropriate, and comprehensive enrichment program is essential to successfully promote the health and wellbeing of captive NHP.

Social effects on foraging behavior and success depend on local environmental conditions

PubMed Central

Marshall, Harry H; Carter, Alecia J; Ashford, Alexandra; Rowcliffe, J Marcus; Cowlishaw, Guy

2015-01-01

In social groups, individuals' dominance rank, social bonds, and kinship with other group members have been shown to influence their foraging behavior. However, there is growing evidence that the particular effects of these social traits may also depend on local environmental conditions. We investigated this by comparing the foraging behavior of wild chacma baboons, Papio ursinus, under natural conditions and in a field experiment where food was spatially clumped. Data were collected from 55 animals across two troops over a 5-month period, including over 900 agonistic foraging interactions and over 600 food patch visits in each condition. In both conditions, low-ranked individuals received more agonism, but this only translated into reduced foraging performances for low-ranked individuals in the high-competition experimental conditions. Our results suggest one possible reason for this pattern may be low-ranked individuals strategically investing social effort to negotiate foraging tolerance, but the rank-offsetting effect of this investment being overwhelmed in the higher-competition experimental environment. Our results also suggest that individuals may use imbalances in their social bonds to negotiate tolerance from others under a wider range of environmental conditions, but utilize the overall strength of their social bonds in more extreme environments where feeding competition is more intense. These findings highlight that behavioral tactics such as the strategic investment of social effort may allow foragers to mitigate the costs of low rank, but that the effectiveness of these tactics is likely to be limited in certain environments. PMID:25691973

Predator Cue and Prey Density Interactively Influence Indirect Effects on Basal Resources in Intertidal Oyster Reefs

PubMed Central

Hughes, A. Randall; Rooker, Kelly; Murdock, Meagan; Kimbro, David L.

2012-01-01

Predators can influence prey abundance and traits by direct consumption, as well as by non-consumptive effects of visual, olfactory, or tactile cues. The strength of these non-consumptive effects (NCEs) can be influenced by a variety of factors, including predator foraging mode, temporal variation in predator cues, and the density of competing prey. Testing the relative importance of these factors for determining NCEs is critical to our understanding of predator-prey interactions in a variety of settings. We addressed this knowledge gap by conducting two mesocosm experiments in a tri-trophic intertidal oyster reef food web. More specifically, we tested how a predatory fish (hardhead catfish, Ariopsis felis) directly influenced their prey (mud crabs, Panopeus spp.) and indirectly affected basal resources (juvenile oysters, Crassostrea virginica), as well as whether these direct and indirect effects changed across a density gradient of competing prey. Per capita crab foraging rates were inversely influenced by crab density, but they were not affected by water-borne predator cues. As a result, direct consumptive effects on prey foraging rates were stronger than non-consumptive effects. In contrast, predator cue and crab density interactively influenced indirect predator effects on oyster mortality in two experiments, with trait-mediated and density-mediated effects of similar magnitude operating to enhance oyster abundance. Consistent differences between a variable predator cue environment and other predator cue treatments (no cue and constant cue) suggests that an understanding of the natural risk environment experienced by prey is critical to testing and interpreting trait-mediated indirect interactions. Further, the prey response to the risk environment may be highly dependent on prey density, particularly in prey populations with strong intra-specific interactions. PMID:22970316

Determinants and outcomes of decision-making, group coordination and social interactions during a foraging experiment in a wild primate.

PubMed

Pyritz, Lennart W; Fichtel, Claudia; Huchard, Elise; Kappeler, Peter M

2013-01-01

Social animals have to coordinate joint movements to maintain group cohesion, but the latter is often compromised by diverging individual interests. A widespread behavioral mechanism to achieve coordination relies on shared or unshared consensus decision-making. If consensus costs are high, group fission represents an alternative tactic. Exploring determinants and outcomes of spontaneous group decisions and coordination of free-ranging animals is methodologically challenging. We therefore conducted a foraging experiment with a group of wild redfronted lemurs (Eulemur rufifrons) to study decision outcomes, coordination of movements, individual foraging benefits and social interactions in response to the presentation of drinking platforms with varying baiting patterns. Behavioral observations were complemented with data from recordings of motion detector cameras installed at the platforms. The animal's behavior in the experimental conditions was compared to natural group movements. We could not determine the type of consensus decision-making because the group visited platforms randomly. The group fissioned during 23.3% of platform visits, and fissioning resulted in more individuals drinking simultaneously. As under natural conditions, adult females initiated most group movements, but overtaking by individuals of different age and sex classes occurred in 67% of movements to platforms, compared to only 18% during other movements. As a result, individual resource intake at the platforms did not depend on departure position, age or sex, but on arrival order. Aggression at the platforms did not affect resource intake, presumably due to low supplanting rates. Our findings highlight the diversity of coordination processes and related consequences for individual foraging benefits in a primate group living under natural conditions.

Altered concentrate to forage ratio in cows ration enhanced bioproduction of specific size subpopulation of milk fat globules.

PubMed

Mesilati-Stahy, Ronit; Moallem, Uzi; Magen, Yogev; Argov-Argaman, Nurit

2015-07-15

The mechanism underlying the shift in milk-fat-globule (MFG) mean diameter upon changing the concentrate-to-forage ratio in dairy cow rations was investigated. Cows were fed high-concentrate low-forage (HCLF) or high-forage low-concentrate (LCHF) rations for 4 weeks. Mean diameter of MFG, determined in raw whole milk, was 0.4 μm larger in the LCHF-fed vs. HCLF-fed group. The main compositional differences between treatments were found in a specific MFG subgroup with the diameter of 3.3 μm (F1), with higher capric, lauric, myristic and lower oleic acid concentrations in HCLF vs. LCHF milk. Similarly, lipid concentration differences between treatments were only found in F1, with higher triglyceride and phosphatidylethanolamine, and lower sphingomyelin concentrations in LCHF vs. HCLF milk. The higher MFG mean diameter in whole raw LCHF milk might therefore be attributed to increased secretion of F1-group MFG, while fat content and composition in the other MFG size groups remains unchanged. Copyright © 2015 Elsevier Ltd. All rights reserved.

Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

USGS Publications Warehouse

Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

2015-01-01

Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation.

Bats aggregate to improve prey search but might be impaired when their density becomes too high.

PubMed

Cvikel, Noam; Egert Berg, Katya; Levin, Eran; Hurme, Edward; Borissov, Ivailo; Boonman, Arjan; Amichai, Eran; Yovel, Yossi

2015-01-19

Social foraging is a very common yet extremely complex behavior. Numerous studies attempted to model it with little supporting evidence. Studying it in the wild is difficult because it requires monitoring the animal's movement, its foraging success, and its interactions with conspecifics. We present a novel system that enables full night ultrasonic recording of freely foraging bats, in addition to GPS tracking. As they rely on echolocation, audio recordings of bats allow tapping into their sensory acquisition of the world. Rapid changes in echolocation allowed us to reveal the bats' dynamic reactions in response to prey or conspecifics—two key behaviors that are extremely difficult to assess in most animals. We found that bats actively aggregate and forage as a group. However, we also found that when the group became too dense, bats were forced to devote sensory attention to conspecifics that frequently entered their biosonar "field of view," impairing the bats' prey detection performance. Why then did bats fly in such high densities? By emitting echolocation calls, bats constantly provide public information about their detection of prey. Bats could therefore benefit from intentionally flying at a distance that enables eavesdropping on conspecifics. Group foraging, therefore, probably allowed bats to effectively operate as an array of sensors, increasing their searching efficiency. We suggest that two opposing forces are at play in determining the efficient foraging density: on the one hand, higher densities improve prey detection, but on the other hand, they increase conspecific interference. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatio-Temporal Dynamics of Foraging Networks in the Grass-Cutting Ant Atta bisphaerica Forel, 1908 (Formicidae, Attini)

PubMed Central

Lopes, Juliane F. S.; Brugger, Mariana S.; Menezes, Regys B.; Camargo, Roberto S.; Forti, Luiz Carlos; Fourcassié, Vincent

2016-01-01

Foraging networks are a key element for ant colonies because they facilitate the flow of resources from the environment to the nest and they allow the sharing of information among individuals. Here we report the results of an 8-month survey, extending from November 2009 to June 2010, of the foraging networks of four mature colonies of Atta bisphaerica, a species of grass-cutting ant which is considered as a pest in Brazil. We found that the distribution of foraging effort was strongly influenced by the landscape features around the nests, in particular by the permanently wet parts of the pasture in which the nests were located. The foraging networks consisted of underground tunnels which opened on average at 21.5m from the nests and of above-ground physical trails that reached on average 4.70m in length. The use of the foraging networks was highly dynamic, with few sections of the networks used for long periods of time. Three different phases, which could be linked to the seasonal change in the local rainfall regime, could be identified in the construction and use of the foraging networks. The first phase corresponded to the beginning of the rainy season and was characterized by a low foraging activity, as well as a low excavation and physical trail construction effort. The second phase, which began in February and extended up to the end of the humid season at the end of March, was characterized by an intense excavation and trail construction effort, resulting in an expansion of the foraging networks. Finally, in the third phase, which corresponded to the beginning of the dry season, the excavation and trail construction effort leveled off or decreased while foraging activity kept increasing. Our hypothesis is that ants could benefit from the underground tunnels and physical trails built during the humid season to maintain their foraging activity at a high level. PMID:26752413

40 CFR 180.418 - Cypermethrin and an isomer zeta-cypermethrin; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... on the following raw agricultural commodities: Commodity Parts per million Alfalfa, hay 15.00 Alfalfa, forage 5.00 Alfalfa, seed 0.50 Almond, hulls 6 Animal feed, nongrass, group 18, forage 8 Animal feed...

Foraging to settled life: a comparative study of anthropometry and nutrition of Onges of Little Andaman Island.

PubMed

Sahani, Ramesh

2013-10-01

The aim of this study is to examine the impact of forced settlement among the foraging Onges, which induced them to change their subsistence from full time foragers to settled consumer. Anthropometric study along with dietary investigation was considered before and afterwards they were forcibly settled. The anthropometric variables and indices show gradual increase among the Onges males but not so much in females. High prevalence of overweight and obesity is also reported. Comparison with other Andaman Islanders indicates that the group which was under the developmental schemes (forced to settle), is showing more mean values of anthropometric variables with prevalence of overweight and obesity than the group, which was not under the influence of developmental programme. Their dietary pattern and physical activity changed to a great extent. The protein content of the diets reduced significantly and the fat along with carbohydrates increased to a substantial amount. The contribution of protein to calories has been reduced substantially and now it is only around 10%, whereas in the past it was above 30%. Caloric intakes increased more than two times, while the physical activity level reduced to about half time. Decreased mobility and altered food habits are the probable reason for the gradual increase of body dimensions and prevalent overweight and obesity, which are the outcomes of forced settlement. Copyright © 2013 Elsevier GmbH. All rights reserved.

Sperm whales reduce foraging effort during exposure to 1-2 kHz sonar and killer whale sounds.

PubMed

Isojunno, Saana; Cure, Charlotte; Kvadsheim, Petter Helgevold; Lam, Frans-Peter Alexander; Tyack, Peter Lloyd; Wensveen, Paul Jacobus; Miller, Patrick James O'Malley

2016-01-01

The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 µPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kHz, source level 199 re 1 µPa m, received sound pressure level [SPL] = 73-158 dB re 1 µPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kHz sonar signals received at lower levels (SPL = 89-133 dB re 1 µPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.

Vessel Noise Affects Beaked Whale Behavior: Results of a Dedicated Acoustic Response Study

DTIC Science & Technology

2012-08-01

the analysis. Gaussian Models Shapiro-Wilk test (Normality) Breusch - Pagan test (Heteroscedasticity) Durbin-Watson test (Independence) Foraging duration...noise) may disrupt behavior. An experiment involving the exposure of target whale groups to intense vessel-generated noise tested how these exposures...exposure of target whale groups to intense vessel-generated noise tested how these exposures influenced the foraging behavior of Blainville?s beaked

Variations in protein and fat contents and their fractions in milk from two species fed different forages.

PubMed

Kholif, S M; El-Shewy, A A; Morsy, T A; Abd El-Rahman, H H

2015-02-01

This study aimed at determining the variations in milk constituents which could be varied by feed and animal species. To achieve this goal, two groups of homoparity Baladi cows and Egyptian buffaloes (n = 20 per species) were used. Each group was divided into two subgroups (n = 10): subgroup I received legume forage (Egyptian clover) and subgroup II received grass forage (sorghum forage). All experimental animals were fed the diet consisting of concentrate, forage and rice straw as 50, 25 and 25% of dry matter intake respectively. Milk samples were taken for analysis. The trial lasted until the 3rd month of parturition. The main results indicated that lactating cattle fed legume forage significantly (p ≤ 0.01) had more content of casein nitrogen (513 mg/100 ml milk), lower content of glutamic acid (23.56 g/100 g milk protein) and more content of cis-9, trans-11 18:2 conjugated linoleic acid (CLA) (0.77 g/100 g milk fat) compared with 433, 26.67 and 0.53, respectively, for cattle fed grass forage. With regard to the species effect, results showed that buffalo milk appeared to contain significantly higher (p ≤ 0.01) contents of casein nitrogen, phenylalanine, glutamic and arachidonic acid compared with cow's milk. However, the latter was significantly (p ≤ 0.01) more in the cis-9, trans-11CLA (0.59 g/100 g milk fat) than that in buffalo milk (0.47 g/100 g milk fat). The results revealed that not only forage type played a critical role in determining the variations of milk nitrogen distribution, milk amino acids and fatty acids but also animal species had a significant effect on these parameters. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

Regulation of C:N:P stoichiometry of microbes and soil organic matter by optimizing enzyme allocation: an omics-informed model study

NASA Astrophysics Data System (ADS)

Song, Y.; Yao, Q.; Wang, G.; Yang, X.; Mayes, M. A.

2017-12-01

Increasing evidences is indicating that soil organic matter (SOM) decomposition and stabilization process is a continuum process and controlled by both microbial functions and their interaction with minerals (known as the microbial efficiency-matrix stabilization theory (MEMS)). Our metagenomics analysis of soil samples from both P-deficit and P-fertilization sites in Panama has demonstrated that community-level enzyme functions could adapt to maximize the acquisition of limiting nutrients and minimize energy demand for foraging (known as the optimal foraging theory). This optimization scheme can mitigate the imbalance of C/P ratio between soil substrate and microbial community and relieve the P limitation on microbial carbon use efficiency over the time. Dynamic allocation of multiple enzyme groups and their interaction with microbial/substrate stoichiometry has rarely been considered in biogeochemical models due to the difficulties in identifying microbial functional groups and quantifying the change in enzyme expression in response to soil nutrient availability. This study aims to represent the omics-informed optimal foraging theory in the Continuum Microbial ENzyme Decomposition model (CoMEND), which was developed to represent the continuum SOM decomposition process following the MEMS theory. The SOM pools in the model are classified based on soil chemical composition (i.e. Carbohydrates, lignin, N-rich SOM and P-rich SOM) and the degree of SOM depolymerization. The enzyme functional groups for decomposition of each SOM pool and N/P mineralization are identified by the relative composition of gene copy numbers. The responses of microbial activities and SOM decomposition to nutrient availability are simulated by optimizing the allocation of enzyme functional groups following the optimal foraging theory. The modeled dynamic enzyme allocation in response to P availability is evaluated by the metagenomics data measured from P addition and P-deficit soil samples in Panama sites.The implementation of dynamic enzyme allocation in response to nutrient availability in the CoMEND model enables us to capture the varying microbial C/P ratio and soil carbon dynamics in response to shifting nutrient constraints over time in tropical soils.

Virus induced gene silencing in Lolium temulentum

USDA-ARS?s Scientific Manuscript database

Lolium temulentum L. is valuable as a model species for studying abiotic stress in closely related forage and turf grasses, many of which are polyploid outcrossing species. As with most monocot species, Agrobacterium-mediated transformation of L. temulentum is still challenging, time consuming and n...

Modification of feeding circuits in the evolution of social behavior.

PubMed

Fischer, Eva K; O'Connell, Lauren A

2017-01-01

Adaptive trade-offs between foraging and social behavior intuitively explain many aspects of individual decision-making. Given the intimate connection between social behavior and feeding/foraging at the behavioral level, we propose that social behaviors are linked to foraging on a mechanistic level, and that modifications of feeding circuits are crucial in the evolution of complex social behaviors. In this Review, we first highlight the overlap between mechanisms underlying foraging and parental care and then expand this argument to consider the manipulation of feeding-related pathways in the evolution of other complex social behaviors. We include examples from diverse taxa to highlight that the independent evolution of complex social behaviors is a variation on the theme of feeding circuit modification. © 2017. Published by The Company of Biologists Ltd.

Effects of Dietary Forage and Calf Starter Diet on Ruminal pH and Bacteria in Holstein Calves during Weaning Transition

PubMed Central

Kim, Yo-Han; Nagata, Rie; Ohtani, Natsuki; Ichijo, Toshihiro; Ikuta, Kentaro; Sato, Shigeru

2016-01-01

We investigated the relationship between ruminal pH and bacteria in calves fed calf starter with and without forage during weaning transition. First, 16 Holstein bull calves were obtained from dairy farms and equipped with rumen cannulas by cannulation surgery. Then, calves (73.5 ± 4.2 kg; mean ± SE) were assigned to groups fed calf starter either with forage (HAY, n = 8) or without forage (CON, n = 8), and all calves were weaned at 8 weeks of age. Ruminal pH was measured continuously, and rumen fluid samples were collected at 7, 8, 9, and 11 weeks of age, namely −1, 0, 1, and 3 weeks after weaning, respectively, to assess volatile fatty acid concentrations and bacterial DNA. The 24-h mean ruminal pH was significantly (P < 0.05) different between the two groups. Diurnal changes in the 1-h mean ruminal pH were observed throughout the study in the HAY group; however, they were not observed at 0 and 1 weeks after weaning in the CON group. Moreover, the HAY group had significantly (P < 0.05) higher proportions of acetate and butyrate and lower proportion of propionate, and significantly (P < 0.05) lower ruminal acetate-to-propionate ratios were observed in the CON group. The ruminal bacterial diversity indices decreased after −1 week in both groups and increased at 0 and 1 weeks after weaning in the HAY and CON groups, respectively. From the 454 pyrosequencing analysis, significant differences (P < 0.05) were observed in the relative abundance of several phyla (Bacteroidetes, Actinobacteria, and Tenericutes) and one genus (Prevotella) between the two groups. From quantitative real-time PCR analysis, the HAY group had the higher copy numbers of cellulolytic bacteria (Ruminococcus flavefaciens and Ruminococcus albus) compared with the CON group. This study demonstrated that feeding of dietary forage alleviates subacute ruminal acidosis due to diurnal changes in ruminal pH. Furthermore, changes in ruminal pH affect the ruminal bacterial diversity and relative abundance, and these changes might have influenced the establishment of fermentative ruminal functions during weaning transition. PMID:27818645

Cooperation and the evolution of hunter-gatherer storytelling.

PubMed

Smith, Daniel; Schlaepfer, Philip; Major, Katie; Dyble, Mark; Page, Abigail E; Thompson, James; Chaudhary, Nikhil; Salali, Gul Deniz; Mace, Ruth; Astete, Leonora; Ngales, Marilyn; Vinicius, Lucio; Migliano, Andrea Bamberg

2017-12-05

Storytelling is a human universal. From gathering around the camp-fire telling tales of ancestors to watching the latest television box-set, humans are inveterate producers and consumers of stories. Despite its ubiquity, little attention has been given to understanding the function and evolution of storytelling. Here we explore the impact of storytelling on hunter-gatherer cooperative behaviour and the individual-level fitness benefits to being a skilled storyteller. Stories told by the Agta, a Filipino hunter-gatherer population, convey messages relevant to coordinating behaviour in a foraging ecology, such as cooperation, sex equality and egalitarianism. These themes are present in narratives from other foraging societies. We also show that the presence of good storytellers is associated with increased cooperation. In return, skilled storytellers are preferred social partners and have greater reproductive success, providing a pathway by which group-beneficial behaviours, such as storytelling, can evolve via individual-level selection. We conclude that one of the adaptive functions of storytelling among hunter gatherers may be to organise cooperation.

Vessel Noise Affects Beaked Whale Behavior: Results of a Dedicated Acoustic Response Study

PubMed Central

Pirotta, Enrico; Milor, Rachael; Quick, Nicola; Moretti, David; Di Marzio, Nancy; Tyack, Peter; Boyd, Ian; Hastie, Gordon

2012-01-01

Some beaked whale species are susceptible to the detrimental effects of anthropogenic noise. Most studies have concentrated on the effects of military sonar, but other forms of acoustic disturbance (e.g. shipping noise) may disrupt behavior. An experiment involving the exposure of target whale groups to intense vessel-generated noise tested how these exposures influenced the foraging behavior of Blainville’s beaked whales (Mesoplodon densirostris) in the Tongue of the Ocean (Bahamas). A military array of bottom-mounted hydrophones was used to measure the response based upon changes in the spatial and temporal pattern of vocalizations. The archived acoustic data were used to compute metrics of the echolocation-based foraging behavior for 16 targeted groups, 10 groups further away on the range, and 26 non-exposed groups. The duration of foraging bouts was not significantly affected by the exposure. Changes in the hydrophone over which the group was most frequently detected occurred as the animals moved around within a foraging bout, and their number was significantly less the closer the whales were to the sound source. Non-exposed groups also had significantly more changes in the primary hydrophone than exposed groups irrespective of distance. Our results suggested that broadband ship noise caused a significant change in beaked whale behavior up to at least 5.2 kilometers away from the vessel. The observed change could potentially correspond to a restriction in the movement of groups, a period of more directional travel, a reduction in the number of individuals clicking within the group, or a response to changes in prey movement. PMID:22880022

Improving diet and activity of insectivorous primates in captivity: Naturalizing the diet of Northern Ceylon gray slender loris, Loris lydekkerianus nordicus.

PubMed

Williams, Emma; Cabana, Francis; Nekaris, K A I

2015-01-01

Data on in-situ diet and nutritional requirements should inform the provision of food to captive insectivorous primates. Despite the growing availability of such information an over-reliance on commercially available primate foods and fruit continues in many captive establishments. Wild slender lorises are almost exclusively insectivorous, yet captive conspecifics are fed a primarily frugivorous diet that is likely to contribute to behavioral and health problems. We investigated the effect of naturalizing diet in the Northern Ceylon grey slender loris (Loris lydekkerianus nordicus) by providing live insect prey to a captive group of five individuals. We calculated activity budgets in accordance with six established categories and recorded positional behaviors. We collected data over 30 hours for each of three conditions: pre-enrichment, enrichment, post-enrichment. We hypothesized that increased opportunity for the display of natural behaviors would be stimulated by the dietary enrichment of live insects and made the following predictions; 1) Percentage time spent foraging would increase and time spent inactive would decrease; 2) behavioral repertoires would increase; 3) foraging patterns would be more constant over time with reduced feeding-time peaks. We analyzed time budget and behavioral changes using Friedman tests. We found significant changes in activity budgets with inactivity reduced and foraging levels increased to levels seen in wild slender lorises. We found a significant increase in postures used in foraging and a wider behavioral repertoire. We discuss the benefits of providing free-ranging live food in relation to enhancing the temporal-spatial distribution of food acquisition, satisfying nutritional requirements, balancing energy intake, and expenditure, expanding sensory stimulation, and promoting behavioral competence. We discuss our findings in relation to other insectivorous primates. © 2015 Wiley Periodicals, Inc.

The effects of age and past and present behavioral specialization on behavior of workers of the red wood ant Formica polyctena Först. during nestmate reunion tests.

PubMed

Korczyńska, Julita; Szczuka, Anna; Symonowicz, Beata; Wnuk, Andrzej; Anna, Gonzalez Szwacka; Mazurkiewicz, Paweł Jarosław; Studnicki, Marcin; Godzińska, Ewa Joanna

2014-09-01

Social insect workers usually participate first in intranidal tasks and then switch to extranidal ones. However, foragers may switch again to intranidal brood care. This process is called the behavioral reversion. We applied dyadic nestmate reunion tests to explore behavioral differences between five groups of workers of the red wood ant Formica polyctena: callows (newly eclosed workers), nurses, reverted nurses (foragers that switched back to intranidal brood care in response to exposure to brood in absence of nurses), and two groups of foragers. Inter-group differences between the tested ants were related both to age and past and present behavioral specialization. Callows were the least active and their behavior was characterized by the lowest tempo. Nurses usually behaved in a way intermediate in respect to behavior of callows and the ants that had already passed the transition to extranidal tasks. The behavior of reverted nurses showed both similarities and differences with respect to behavior of foragers. Some traits of behavior of reverted nurses were similar as in the case of nurses, or intermediate in respect to both nurses and foragers. Behavioral reversion of workers of F. polyctena has thus other behavioral correlates besides the reappearance of intranidal brood care. Copyright © 2014 Elsevier B.V. All rights reserved.

Nutrient-Mediated Architectural Plasticity of a Predatory Trap

PubMed Central

Blamires, Sean J.; Tso, I-Min

2013-01-01

Background Nutrients such as protein may be actively sought by foraging animals. Many predators exhibit foraging plasticity, but how their foraging strategies are affected when faced with nutrient deprivation is largely unknown. In spiders, the assimilation of protein into silk may be in conflict with somatic processes so we predicted web building to be affected under protein depletion. Methodology/Principal Findings To assess the influence of protein intake on foraging plasticity we fed the orb-web spiders Argiope aemula and Cyclosa mulmeinensis high, low or no protein solutions over 10 days and allowed them to build webs. We compared post-feeding web architectural components and major ampullate (MA) silk amino acid compositions. We found that the number of radii in webs increased in both species when fed high protein solutions. Mesh size increased in A. aemula when fed a high protein solution. MA silk proline and alanine compositions varied in each species with contrasting variations in alanine between the two species. Glycine compositions only varied in C. mulmeinensis silk. No spiders significantly lost or gained mass on any feeding treatment, so they did not sacrifice somatic maintenance for amino acid investment in silk. Conclusions/Significance Our results show that the amount of protein taken in significantly affects the foraging decisions of trap-building predators, such as orb web spiders. Nevertheless, the subtle differences found between species in the association between protein intake, the amino acids invested in silk and web architectural plasticity show that the influence of protein deprivation on specific foraging strategies differs among different spiders. PMID:23349928

The Fungus Aspergillus aculeatus Enhances Salt-Stress Tolerance, Metabolite Accumulation, and Improves Forage Quality in Perennial Ryegrass

PubMed Central

Li, Xiaoning; Han, Shijuan; Wang, Guangyang; Liu, Xiaoying; Amombo, Erick; Xie, Yan; Fu, Jinmin

2017-01-01

Perennial ryegrass (Lolium perenne) is an important forage grass with high yield and superior quality in temperate regions which is widely used in parks, sport field, and other places. However, perennial ryegrass is moderately tolerant to salinity stress compared to other commercial cultivars and salt stress reduces their growth and productivity. Aspergillus aculeatus has been documented to participate in alleviating damage induced by salinity. Therefore, the objective of this study was to investigate the mechanisms underlying A. aculeatus-mediated salt tolerance, and forage quality of perennial ryegrass exposed to 0, 200, and 400 mM NaCl concentrations. Physiological markers and forage quality of perennial ryegrass to salt stress were evaluated based on the growth rate, photosynthesis, antioxidant enzymes activity, lipid peroxidation, ionic homeostasis, the nutritional value of forage, and metabolites. Plants inoculated with A. aculeatus exhibited higher relative growth rate (RGR), turf and forage quality under salt stress than un-inoculated plants. Moreover, in inoculated plants, the fungus remarkably improved plant photosynthetic efficiency, reduced the antioxidant enzymes activity (POD and CAT), and attenuated lipid peroxidation (decreased H2O2 and MDA accumulation) induced by salinity, compared to un-inoculated plants. Furthermore, the fungus also acts as an important role in maintaining the lower Na/K ratio and metabolites and lower the amino acids (Alanine, Proline, GABA, and Asparagine), and soluble sugars (Glucose and Fructose) for inoculated plants than un-inoculated ones. Our results suggest that A. aculeatus may be involved in modulating perennial ryegrass tolerance to salinity in various ways. PMID:28936200

Accelerated behavioural development changes fine-scale search behaviour and spatial memory in honey bees (Apis mellifera L.).

PubMed

Ushitani, Tomokazu; Perry, Clint J; Cheng, Ken; Barron, Andrew B

2016-02-01

Normally, worker honey bees (Apis mellifera) begin foraging when more than 2 weeks old as adults, but if individual bees or the colony is stressed, bees often begin foraging precociously. Here, we examined whether bees that accelerated their behavioural development to begin foraging precociously differed from normal-aged foragers in cognitive performance. We used a social manipulation to generate precocious foragers from small experimental colonies and tested their performance in a free-flight visual reversal learning task, and a test of spatial memory. To assess spatial memory, bees were trained to learn the location of a small sucrose feeder within an array of three landmarks. In tests, the feeder and one landmark were removed and the search behaviour of the bees was recorded. Performance of precocious and normal-aged foragers did not differ in a visual reversal learning task, but the two groups showed a clear difference in spatial memory. Flight behaviour suggested normal-aged foragers were better able to infer the position of the removed landmark and feeder relative to the remaining landmarks than precocious foragers. Previous studies have documented the cognitive decline of old foragers, but this is the first suggestion of a cognitive deficit in young foragers. These data imply that worker honey bees continue their cognitive development during the adult stage. These findings may also help to explain why precocious foragers perform quite poorly as foragers and have a higher than normal loss rate. © 2016. Published by The Company of Biologists Ltd.

Info-gap robust-satisficing model of foraging behavior: do foragers optimize or satisfice?

PubMed

Carmel, Yohay; Ben-Haim, Yakov

2005-11-01

In this note we compare two mathematical models of foraging that reflect two competing theories of animal behavior: optimizing and robust satisficing. The optimal-foraging model is based on the marginal value theorem (MVT). The robust-satisficing model developed here is an application of info-gap decision theory. The info-gap robust-satisficing model relates to the same circumstances described by the MVT. We show how these two alternatives translate into specific predictions that at some points are quite disparate. We test these alternative predictions against available data collected in numerous field studies with a large number of species from diverse taxonomic groups. We show that a large majority of studies appear to support the robust-satisficing model and reject the optimal-foraging model.

Long-term effects of the 'Exxon Valdez' oil spill: Sea otter foraging in the intertidal as a pathway of exposure to lingering oil

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Coletti, Heather A.; Esslinger, George G.; Kloecker, Kimberly A.; Rice, Stanley D.; Reed, John; Monson, Daniel H.

2012-01-01

The protracted recovery of some bird and mammal populations in western Prince William Sound (WPWS), Alaska, and the persistence of spilled 'Exxon Valdez' oil in intertidal sediments, suggests a pathway of exposure to consumers that occupy nearshore habitats. To evaluate the hypothesis that sea otter (Enhydra lutris) foraging allows access to lingering oil, we contrast spatial relations between foraging behavior and documented oil distribution. We recovered archival time-depth recorders implanted in 19 sea otters in WPWS, where lingering oil and delayed ecosystem recovery are well documented. Sea otter foraging dives ranged from +2.7 to -92 m below sea level (MLLW), with intertidal accounting for 5 to 38% of all foraging. On average, female sea otters made 16050 intertidal dives per year and 18% of these dives were at depths above the +0.80 m tidal elevation. Males made 4100 intertidal dives per year and 26% of intertidal foraging took place at depths above the +0.80 m tidal elevation. Estimated annual oil encounter rates ranged from 2 to 24 times yr-1 for females, and 2 to 4 times yr-1 for males. Exposure rates increased in spring when intertidal foraging doubled and females were with small pups. In summer 2008, we found sea otter foraging pits on 13.5 of 24.8 km of intertidal shoreline surveyed. Most pits (82%) were within 0.5 m of the zero tidal elevation and 15% were above 0.5 m, the level above which most (65%) lingering oil remains. In August 2008, we detected oil above background concentrations in 18 of 41 (44%) pits excavated by sea otters on beaches with prior evidence of oiling, with total PAH concentrations up to 56000 ng g−1 dry weight. Our estimates of intertidal foraging, the widespread presence of foraging pits in the intertidal, and the presence of oil in and near sea otter foraging pits documents a pathway of exposure from lingering intertidal oil to sea otters foraging in WPWS.

Cumulative Effects of Foraging Behavior and Social Dominance on Brain Development in a Facultatively Social Bee (Ceratina australensis).

PubMed

Rehan, Sandra M; Bulova, Susan J; O'Donnell, Sean

2015-01-01

In social insects, both task performance (foraging) and dominance are associated with increased brain investment, particularly in the mushroom bodies. Whether and how these factors interact is unknown. Here we present data on a system where task performance and social behavior can be analyzed simultaneously: the small carpenter bee Ceratina australensis. We show that foraging and dominance have separate and combined cumulative effects on mushroom body calyx investment. Female C. australensis nest solitarily and socially in the same populations at the same time. Social colonies comprise two sisters: the social primary, which monopolizes foraging and reproduction, and the social secondary, which is neither a forager nor reproductive but rather remains at the nest as a guard. We compare the brains of solitary females that forage and reproduce but do not engage in social interactions with those of social individuals while controlling for age, reproductive status, and foraging experience. Mushroom body calyx volume was positively correlated with wing wear, a proxy for foraging experience. We also found that, although total brain volume did not vary among reproductive strategies (solitary vs. social nesters), socially dominant primaries had larger mushroom body calyx volumes (corrected for both brain and body size variation) than solitary females; socially subordinate secondaries (that are neither dominant nor foragers) had the least-developed mushroom body calyces. These data demonstrate that sociality itself does not explain mushroom body volume; however, achieving and maintaining dominance status in a group was associated with mushroom body calyx enlargement. Dominance and foraging effects were cumulative; dominant social primary foragers had larger mushroom body volumes than solitary foragers, and solitary foragers had larger mushroom body volumes than nonforaging social secondary guards. This is the first evidence for cumulative effects on brain development by dominance and task performance.

Age-related variation in limb bone diaphyseal structure among Inuit foragers from Point Hope, northern Alaska.

PubMed

Wallace, I J; Nesbitt, A; Mongle, C; Gould, E S; Grine, F E

2014-01-01

Age-related deterioration of limb bone diaphyseal structure is documented among precontact Inuit foragers from northern Alaska. These findings challenge the concept that bone loss and fracture susceptibility among modern Inuit stem from their transition away from a physically demanding traditional lifestyle toward a more sedentary Western lifestyle. Skeletal fragility is rare among foragers and other traditional-living societies, likely due to their high physical activity levels. Among modern Inuit, however, severe bone loss and fractures are apparently common. This is possibly because of recent Western influences and increasing sedentism. To determine whether compromised bone structure and strength among the Inuit are indeed aberrant for a traditional-living group, data were collected on age-related variation in limb bone diaphyseal structure from a group predating Western influences. Skeletons of 184 adults were analyzed from the Point Hope archaeological site. Mid-diaphyseal structure was measured in the humerus, radius, ulna, femur, and tibia using CT. Structural differences were assessed between young, middle-aged, and old individuals. In all bones examined, both females and males exhibited significant age-related reductions in bone quantity. With few exceptions, total bone (periosteal) area did not significantly increase between young and old age in either sex, nor did geometric components of bending rigidity (second moments of area). While the physically demanding lifestyles of certain traditional-living groups may protect against bone loss and fracture susceptibility, this is not the case among the Inuit. It remains possible, however, that Western characteristics of the modern Inuit lifestyle exacerbate age-related skeletal deterioration.

Coordination and Synchronisation of Anti-Predation Vigilance in Two Crane Species

PubMed Central

Ge, Chen; Beauchamp, Guy; Li, Zhongqiu

2011-01-01

Much of the previous research on anti-predation vigilance in groups has assumed independent scanning for threats among group members. Alternative patterns that are based on monitoring the vigilance levels of companions can also be adaptive. Coordination of vigilance, in which foragers avoid scanning at the same time as others, should decrease the odds that no group member is alert. Synchronisation of vigilance implies that individuals are more likely to be vigilant when companions are already vigilant. While synchronisation will increase the odds that no one is vigilant, it may allow a better assessment of potential threats. We investigated temporal sequences of vigilance in family flocks consisting of two parents and at most two juveniles in two species of cranes in coastal China. We established whether the observed probability that at least one parent is alert was greater (coordination) or lower (synchronisation) than that predicted under the null hypothesis of independent vigilance. We documented coordination of vigilance in common cranes (Grus grus) foraging in an area with high potential for disturbance by people. We documented synchronisation of vigilance in red-crowned cranes (Grus japonensis) in the less but not in the more disturbed area. Coordination in small flocks leads to high collective vigilance but low foraging rates that may not be suitable in areas with low disturbance. We also argue that synchronisation should break down in areas with high disturbance because periods with low vigilance are riskier. Results highlight the view that temporal patterns of vigilance can take many forms depending on ecological factors. PMID:22028880

Coordination and synchronisation of anti-predation vigilance in two crane species.

PubMed

Ge, Chen; Beauchamp, Guy; Li, Zhongqiu

2011-01-01

Much of the previous research on anti-predation vigilance in groups has assumed independent scanning for threats among group members. Alternative patterns that are based on monitoring the vigilance levels of companions can also be adaptive. Coordination of vigilance, in which foragers avoid scanning at the same time as others, should decrease the odds that no group member is alert. Synchronisation of vigilance implies that individuals are more likely to be vigilant when companions are already vigilant. While synchronisation will increase the odds that no one is vigilant, it may allow a better assessment of potential threats. We investigated temporal sequences of vigilance in family flocks consisting of two parents and at most two juveniles in two species of cranes in coastal China. We established whether the observed probability that at least one parent is alert was greater (coordination) or lower (synchronisation) than that predicted under the null hypothesis of independent vigilance. We documented coordination of vigilance in common cranes (Grus grus) foraging in an area with high potential for disturbance by people. We documented synchronisation of vigilance in red-crowned cranes (Grus japonensis) in the less but not in the more disturbed area. Coordination in small flocks leads to high collective vigilance but low foraging rates that may not be suitable in areas with low disturbance. We also argue that synchronisation should break down in areas with high disturbance because periods with low vigilance are riskier. Results highlight the view that temporal patterns of vigilance can take many forms depending on ecological factors.

The importance of delineating networks by activity type in bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida

PubMed Central

Gazda, Stefanie; Iyer, Swami; Killingback, Timothy; Connor, Richard; Brault, Solange

2015-01-01

Network analysis has proved to be a valuable tool for studying the behavioural patterns of complex social animals. Often such studies either do not distinguish between different behavioural states of the organisms or simply focus attention on a single behavioural state to the exclusion of all others. In either of these approaches it is impossible to ascertain how the behavioural patterns of individuals depend on the type of activity they are engaged in. Here we report on a network-based analysis of the behavioural associations in a population of bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida. We consider three distinct behavioural states—socializing, travelling and foraging—and analyse the association networks corresponding to each activity. Moreover, in constructing the different activity networks we do not simply record a spatial association between two individuals as being either present or absent, but rather quantify the degree of any association, thus allowing us to construct weighted networks describing each activity. The results of these weighted activity networks indicate that networks can reveal detailed patterns of bottlenose dolphins at the population level; dolphins socialize in large groups with preferential associations; travel in small groups with preferential associates; and spread out to forage in very small, weakly connected groups. There is some overlap in the socialize and travel networks but little overlap between the forage and other networks. This indicates that the social bonds maintained in other activities are less important as they forage on dispersed, solitary prey. The overall network, not sorted by activity, does not accurately represent any of these patterns. PMID:26064611

Kidnapping of chicks in emperor penguins: a hormonal by-product?

PubMed

Angelier, Frédéric; Barbraud, Christophe; Lormée, Hervé; Prud'homme, François; Chastel, Olivier

2006-04-01

The function and causes of kidnapping juveniles are little understood because individuals sustain some breeding costs to rear an unrelated offspring. Here we focus on the proximal causes of this behaviour in emperor penguins (Aptenodytes forsteri), whose failed breeders often kidnap chicks. We experimentally tested the hypothesis that kidnapping behaviour was the result of high residual levels of prolactin (PRL), a hormone involved in parental behaviour. Penguins with artificially decreased PRL levels by bromocriptine administration kidnapped chicks less often than control penguins. Within the bromocriptine treated group, kidnapping behaviour was not totally suppressed and the probability of kidnapping a chick was positively correlated to PRL levels measured before treatment. During breeding, emperor penguins have to forage in remote ice-free areas. In these birds, PRL secretion is poorly influenced by chick stimuli and has probably evolved to maintain a willingness to return to the colony after a long absence at sea. Therefore, penguins that have lost their chick during a foraging trip still maintain high residual PRL levels and this, combined with colonial breeding, probably facilitates kidnapping. We suggest that kidnapping in non-cooperative systems may result from a hormonal byproduct of a reproductive adaptation to extreme conditions.

Delineation of the southern elephant seal's main foraging environments defined by temperature and light conditions

NASA Astrophysics Data System (ADS)

Vacquié-Garcia, Jade; Guinet, Christophe; Laurent, Cécile; Bailleul, Frédéric

2015-03-01

Changes in marine environments, induced by the global warming, are likely to influence the prey field distribution and consequently the foraging behaviour and the distribution of top marine predators. Thanks to bio-logging, the simultaneous measurements of fine-scale foraging behaviors and oceanographic parameters by predators allow characterizing their foraging environments and provide insights into their prey distribution. In this context, we propose to delimit and to characterize the foraging environments of a marine predator, the Southern Elephant Seal (SES). To do so, the relationship between oceanographic factors and prey encounter events (PEE) was investigated in 12 females SES from Kerguelen Island simultaneously equipped with accelerometers and with a range of physical sensors (temperature, light and depth). PEEs were assessed from the accelerometer data at high spatio-temporal precision while the physical sensors allowed the continuous monitoring of environmental conditions encountered by the SES when diving. First, visited and foraging environments were distinguished according to the oceanographic conditions encountered in the absence and in presence of PEE. Then, a hierarchical classification of the physical parameters recorded during PEEs led to the distinction of five different foraging environments. These foraging environments were structured according to the main frontal systems of the SO. One was located north to the subantarctic front (SAF) and characterized by high temperature and depth, and low light levels. Another, characterized by intermediate levels of temperature, light and depth, was located between the SAF and the polar front (PF). And finally, the last three environments were all found south to the PF and, characterized by low temperature but highly variable depth and light levels. The large physical and/or spatial differences found between these environments suggest that, depending on the location, different prey communities are targeted by SES over a broad range of water temperature, light level and depth conditions. This result highlights the versatility of this marine predator. In addition, in most cases, PEEs were found deeper during the day than during the night, which is indicative of mesopelagic prey performing nycthemeral migration, a behaviour consistent with myctophids species thought to represent the bulk of Kerguelen SES female diets.

Lotus tenuis x L. corniculatus interspecific hybridization as a means to breed bloat-safe pastures and gain insight into the genetic control of proanthocyanidin biosynthesis in legumes

PubMed Central

2014-01-01

Background Proanthocyanidins (PAs) are secondary metabolites that strongly affect plant quality traits. The concentration and the structure of these metabolites influence the palatability and nutritional value of forage legumes. Hence, modulating PAs in the leaves of forage legumes is of paramount relevance for forage breeders worldwide. The lack of genetic variation in the leaf PA trait within the most important forage species and the difficulties in engineering this pathway via the ectopic expression of regulatory genes, prompted us to pursue alternative strategies to enhance this trait in forage legumes of agronomic interest. The Lotus genus includes forage species which accumulate PAs in edible organs and can thus be used as potential donor parents in breeding programs. Results We recovered a wild, diploid and PA-rich population of L. corniculatus and crossed with L. tenuis. The former grows in an alkaline-salty area in Spain while the latter is a diploid species, grown extensively in South American pastures, which does not accumulate PAs in the herbage. The resulting interspecific hybrids displayed several traits of outstanding agronomic relevance such as rhizome production, PA levels in edible tissues sufficient to prevent ruminal bloating (around 5 mg of PAs/g DW), biomass production similar to the cultivated parent and potential for adaptability to marginal lands. We show that PA levels correlate with expression levels of the R2R3MYB transcription factor TT2 and, in turn, with those of the key structural genes of the epicatechin and catechin biosynthetic pathways leading to PA biosynthesis. Conclusions The L. tenuis x L. corniculatus hybrids, reported herein, represent the first example of the introgression of the PA trait in forage legumes to levels known to provide nutritional and health benefits to ruminants. Apart from PAs, the hybrids have additional traits which may prove useful to breed forage legumes with increased persistence and adaptability to marginal conditions. Finally, our study suggests the hybrids and their progeny are an invaluable tool to gain a leap forward in our understanding of the genetic control of PA biosynthesis and tolerance to stresses in legumes. PMID:24490637

Comparison of 3 tall fescue-based stocker systems.

PubMed

Bailey, N J; Kallenbach, R L

2010-05-01

A 2-yr production study was conducted to evaluate 3 systems of growing stocker calves under rotational stocking. One group of steers was stocked on pasture from early April to mid August (spring-stocked steers = SSS), and another group of steers was stocked from early July to late October (fall-stocked steers = FSS). Steers were stratified by BW (n = 72, BW = 229 +/- 11 kg for SSS; n = 72, BW = 248 +/- 18 kg for FSS) and randomly assigned to 1 of 3 treatments. The 3 treatments were 1) rotationally stocked only (control; CON), steers rotated to a new paddock as forage availability dropped below acceptable levels in the occupied paddock; 2) rotationally stocked with distillers grains (DIST); this was the same as CON except steers were supplemented with varying amounts of distillers dried grains with solubles (DDGS) based on forage nutritive value; and 3) rotationally stocked with round-bale silage (SIL); excess forage in spring was harvested and stored as round-bale silage and fed back as needed. Total BW gain/ha over the entire grazing season did not differ between DIST and SIL (P = 0.09) steers, but both were greater than CON (P < 0.01). Total BW gain/ha for DIST, SIL, and CON was 459 (SEM = 11.5), 402 (SEM = 31.0), and 276 (SEM = 26.2) kg, respectively. For ADG, there was a group x year (P < 0.01) and group x treatment (P = 0.02) interaction. Steer ADG for SSS did not differ between SIL and DIST (P = 0.51), but was greater than the CON (P = 0.01). The ADG for SSS was 0.79 (SEM = 0.04), 0.81 (SEM = 0.05), and 0.62 (SEM = 0.05) kg for DIST, SIL, and CON, respectively. For the FSS, ADG for all 3 treatments was different (P = 0.02). The FSS ADG was 0.72 (SEM = 0.03), 0.53 (SEM = 0.04), and 0.29 (SEM = 0.04) kg for DIST, SIL, and CON, respectively. The only treatment with equivalent (P = 0.07) ADG between early and late-stocked steers (SSS vs. FSS) was DIST. Adjusting the amount of DDGS supplemented to steers based on forage nutritive value resulted in consistent BW gains throughout the grazing study, whereas steers in the SIL and CON treatments gained less BW during the latter portion of the season. Controlling forage maturity by removal in the SIL treatment resulted in total BW gains/ha that were not different than the DIST treatment.

Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects.

PubMed

Travers-Trolet, Morgane; Shin, Yunne-Jai; Shannon, Lynne J; Moloney, Coleen L; Field, John G

2014-01-01

The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N2P2Z2D2-OSMOSE). Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects of fishing and environmental variability.

Combined Fishing and Climate Forcing in the Southern Benguela Upwelling Ecosystem: An End-to-End Modelling Approach Reveals Dampened Effects

PubMed Central

Travers-Trolet, Morgane; Shin, Yunne-Jai; Shannon, Lynne J.; Moloney, Coleen L.; Field, John G.

2014-01-01

The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N2P2Z2D2-OSMOSE). Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects of fishing and environmental variability. PMID:24710351

Wheat pasture bloat dynamics, in vitro ruminal gas production, and potential bloat mitigation with condensed tannins.

PubMed

Min, B R; Pinchak, W E; Fulford, J D; Puchala, R

2005-06-01

The aim of this study was to determine the effect of winter wheat (Triticum aestivum L.) forage growth stage, forage allowance, time of day, and commercial condensed tannins (CT) on steer bloat dynamics and in vitro ruminal gas production. Twenty-six crossbreed steers (Angus x Hereford x Salers; average initial BW = 194 +/- 26 kg) were used. Wheat forage allowances were either 18 kg (high forage allowance) and 6 kg (low forage allowance) of DM/(100 kg BW.d). In each bloat observation period, fresh wheat forage samples were hand-clipped to ground level in all study pastures for nutrient and in vitro ruminal gas production analyses. In vitro ruminal gas accumulation was measured at 0, 1, 2, 3, 4, 5, 6, and 12 h. Commercial CT was added at 0, 10, 15, and 20 mg of CT/g of DM. Bloat was scored once per week on two consecutive days at 0800 and 1500 during the vegetative stage and once every 2 wk during the reproductive stage of wheat development. Mean bloat score was calculated for each steer by time of day, stage of plant growth, and forage allowance. Bloat was detected in 65.8% of the observation periods. Average bloat scores were four and 2.5 times greater (P < 0.05) in cattle grazing at a high forage allowance than at a low forage allowance in the vegetative and reproductive growth phases of wheat, respectively. Rate of gas production was greater (P < 0.001) in the vegetative stage than in the reproductive stage. Steer bloat score was positively correlated with forage CP (r = 0.22; P < 0.05) and IVDMD (r = 0.32; P < 0.05). Rate of ruminal gas production was positively correlated (P < 0.01) to forage CP (r = 0.48), NPN (r = 0.40), soluble protein (r = 0.32), and IVDMD (r = 0.47). Conversely, negative correlations were found for forage DM (r = -0.20; P < 0.05), insoluble protein (r = -0.40), NDF (r = -0.69), and forage height (r = -0.49; P < 0.01) on the rate of ruminal gas production. Addition of CT at levels greater than 10 mg of CT/g of DM decreased (P < 0.05) the rate of in vitro ruminal gas and methane gas production after 5 h of incubation. Wheat pasture bloat is a complex disorder that varies across an array of forage and environmental conditions. Condensed tannins have the potential to decrease bloat by altering ruminal gas production and soluble protein digestibility from wheat forage.

Behavioural and physiological responses of birds to environmentally relevant concentrations of an antidepressant

PubMed Central

Bean, Tom G.; Boxall, Alistair B. A.; Lane, Julie; Herborn, Katherine A.; Pietravalle, Stéphane; Arnold, Kathryn E.

2014-01-01

Many wildlife species forage on sewage-contaminated food, for example, at wastewater treatment plants and on fields fertilized with sewage sludge. The resultant exposure to human pharmaceuticals remains poorly studied for terrestrial species. On the basis of predicted exposure levels in the wild, we administered the common antidepressant fluoxetine (FLUOX) or control treatment via prey to wild-caught starlings (Sturnus vulgaris) for 22 weeks over winter. To investigate responses to fluoxetine, birds were moved from their group aviaries into individual cages for 2 days. Boldness, exploration and activity levels showed no treatment effects but controls and FLUOX birds habituated differently to isolation in terms of the concentration of corticosterone (CORT) metabolites in faeces. The controls that excreted higher concentrations of CORT metabolites on day 1 lost more body mass by day 2 of isolation than those which excreted lower levels of CORT metabolites. CORT metabolites and mass loss were unrelated in FLUOX birds. When we investigated the movements of birds in their group aviaries, we found the controls made a higher frequency of visits to food trays than FLUOX birds around the important foraging periods of sunrise and sunset, as is optimal for wintering birds. Although individual variability makes interpreting the sub-lethal endpoints measured challenging, our data suggest that fluoxetine at environmentally relevant concentrations can significantly alter behaviour and physiology. PMID:25405964

Social familiarity modulates group living and foraging behaviour of juvenile predatory mites

NASA Astrophysics Data System (ADS)

Strodl, Markus A.; Schausberger, Peter

2012-04-01

Environmental stressors during early life may have persistent consequences for phenotypic development and fitness. In group-living species, an important stressor during juvenile development is the presence and familiarity status of conspecific individuals. To alleviate intraspecific conflicts during juvenile development, many animals evolved the ability to discriminate familiar and unfamiliar individuals based on prior association and use this ability to preferentially associate with familiar individuals. Assuming that familiar neighbours require less attention than unfamiliar ones, as predicted by limited attention theory, assorting with familiar individuals should increase the efficiency in other tasks. We assessed the influence of social familiarity on within-group association behaviour, development and foraging of juvenile life stages of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. The observed groups consisted either of mixed-age familiar and unfamiliar juvenile mites or of age-synchronized familiar or unfamiliar juvenile mites or of pairs of familiar or unfamiliar larvae. Overall, familiar mites preferentially grouped together and foraged more efficiently, i.e. needed less prey at similar developmental speed and body size at maturity, than unfamiliar mites. Preferential association of familiar mites was also apparent in the inter-exuviae distances. Social familiarity was established by imprinting in the larval stage, was not cancelled or overridden by later conspecific contacts and persisted into adulthood. Life stage had an effect on grouping with larvae being closer together than nymphal stages. Ultimately, optimized foraging during the developmental phase may relax within-group competition, enhance current and future food supply needed for optimal development and optimize patch exploitation and leaving under limited food.

Electrocommunication behaviour during social interactions in two species of pulse-type weakly electric fishes (Mormyridae).

PubMed

Gebhardt, K; Böhme, M; von der Emde, G

2012-12-01

This study compares electrocommunication behaviour in groups of freely swimming weakly electric fishes of two species, Marcusenius altisambesi and Mormyrus rume. Animals emitted variable temporal sequences of stereotyped electric organ discharges (EOD) that served as communication signals. While the waveform of individual signals remained constant, the inter-discharge interval (IDI) patterns conveyed situation-specific information. Both species showed different types of group behaviour, e.g. they engaged in collective (group) foraging. The results show that in each species, during different behavioural conditions (resting, foraging and agonistic encounters), certain situation-specific IDI patterns occurred. In both species, neighbouring fishes swimming closely together interacted electrically by going in and out of synchronization episodes, i.e. periods of temporally correlated EOD production. These often resulted in echo responses between neighbours. During group foraging, fishes often signalled in a repetitive fixed order (fixed-order signalling). During foraging, EOD emission rates of M. altisambesi were higher and more regular than those of M. rume. The two species also differed in the quantity of group behaviours with M. altisambesi being more social than M. rume, which was reflected in the lack of specific agonistic IDI patterns, more fixed-order signalling and more communal resting behaviour in M. altisambesi. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Seabird acoustic communication at sea: a new perspective using bio-logging devices.

PubMed

Thiebault, Andréa; Pistorius, Pierre; Mullers, Ralf; Tremblay, Yann

2016-08-05

Most seabirds are very noisy at their breeding colonies, when aggregated in high densities. Calls are used for individual recognition and also emitted during agonistic interactions. When at sea, many seabirds aggregate over patchily distributed resources and may benefit from foraging in groups. Because these aggregations are so common, it raises the question of whether seabirds use acoustic communication when foraging at sea? We deployed video-cameras with built in microphones on 36 Cape gannets (Morus capensis) during the breeding season of 2010-2011 at Bird Island (Algoa Bay, South Africa) to study their foraging behaviour and vocal activity at sea. Group formation was derived from the camera footage. During ~42 h, calls were recorded on 72 occasions from 16 birds. Vocalization exclusively took place in the presence of conspecifics, and mostly in feeding aggregations (81% of the vocalizations). From the observation of the behaviours of birds associated with the emission of calls, we suggest that the calls were emitted to avoid collisions between birds. Our observations show that at least some seabirds use acoustic communication when foraging at sea. These findings open up new perspectives for research on seabirds foraging ecology and their interactions at sea.

Seabird acoustic communication at sea: a new perspective using bio-logging devices

PubMed Central

Thiebault, Andréa; Pistorius, Pierre; Mullers, Ralf; Tremblay, Yann

2016-01-01

Most seabirds are very noisy at their breeding colonies, when aggregated in high densities. Calls are used for individual recognition and also emitted during agonistic interactions. When at sea, many seabirds aggregate over patchily distributed resources and may benefit from foraging in groups. Because these aggregations are so common, it raises the question of whether seabirds use acoustic communication when foraging at sea? We deployed video-cameras with built in microphones on 36 Cape gannets (Morus capensis) during the breeding season of 2010–2011 at Bird Island (Algoa Bay, South Africa) to study their foraging behaviour and vocal activity at sea. Group formation was derived from the camera footage. During ~42 h, calls were recorded on 72 occasions from 16 birds. Vocalization exclusively took place in the presence of conspecifics, and mostly in feeding aggregations (81% of the vocalizations). From the observation of the behaviours of birds associated with the emission of calls, we suggest that the calls were emitted to avoid collisions between birds. Our observations show that at least some seabirds use acoustic communication when foraging at sea. These findings open up new perspectives for research on seabirds foraging ecology and their interactions at sea. PMID:27492779

The effect of the lunar cycle on fecal cortisol metabolite levels and foraging ecology of nocturnally and diurnally active spiny mice.

PubMed

Gutman, Roee; Dayan, Tamar; Levy, Ofir; Schubert, Iris; Kronfeld-Schor, Noga

2011-01-01

We studied stress hormones and foraging of nocturnal Acomys cahirinus and diurnal A. russatus in field populations as well as in two field enclosures populated by both species and two field enclosures with individuals of A. russatus alone. When alone, A. russatus individuals become also nocturnally active. We asked whether nocturnally active A. russatus will respond to moon phase and whether this response will be obtained also in diurnally active individuals. We studied giving-up densities (GUDs) in artificial foraging patches and fecal cortisol metabolite levels. Both species exhibited elevated fecal cortisol metabolite levels and foraged to higher GUDs in full moon nights; thus A. russatus retains physiological response and behavioral patterns that correlate with full moon conditions, as can be expected in nocturnal rodents, in spite of its diurnal activity. The endocrinological and behavioral response of this diurnal species to moon phase reflects its evolutionary heritage.

Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

PubMed Central

Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

2015-01-01

Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation. PMID:26085591

Pollen foraging: learning a complex motor skill by bumblebees (Bombus terrestris)

NASA Astrophysics Data System (ADS)

Raine, Nigel E.; Chittka, Lars

2007-06-01

To investigate how bumblebees (Bombus terrestris) learn the complex motor skills involved in pollen foraging, we observed naïve workers foraging on arrays of nectarless poppy flowers (Papaver rhoeas) in a greenhouse. Foraging skills were quantified by measuring the pollen load collected during each foraging bout and relating this to the number of flowers visited and bout duration on two consecutive days. The pollen standing crop (PSC) in each flower decreased drastically from 0530 to 0900 hours. Therefore, we related foraging performance to the changing levels of pollen available (per flower) and found that collection rate increased over the course of four consecutive foraging bouts (comprising between 277 and 354 individual flower visits), suggesting that learning to forage for pollen represents a substantial time investment for individual foragers. The pollen collection rate and size of pollen loads collected at the start of day 2 were markedly lower than at the end of day 1, suggesting that components of pollen foraging behaviour could be subject to imperfect overnight retention. Our results suggest that learning the necessary motor skills to collect pollen effectively from morphologically simple flowers takes three times as many visits as learning how to handle the most morphologically complex flowers to extract nectar, potentially explaining why bees are more specialised in their choice of pollen flowers.

Thiamethoxam: Assessing flight activity of honeybees foraging on treated oilseed rape using radio frequency identification technology.

PubMed

Thompson, Helen; Coulson, Mike; Ruddle, Natalie; Wilkins, Selwyn; Harkin, Sarah

2016-02-01

The present study was designed to assess homing behavior of bees foraging on winter oilseed rape grown from seed treated with thiamethoxam (as Cruiser OSR), with 1 field drilled with thiamethoxam-treated seed and 2 control fields drilled with fungicide-only-treated seed. Twelve honeybee colonies were used per treatment group, 4 each located at the field edge (on-field site), at approximately 500 m and 1000 m from the field. A total of nearly 300 newly emerged bees per colony were fitted (tagged) with Mic3 radio frequency identification (RFID) transponders and introduced into each of the 36 study hives. The RFID readers fitted to the entrances of the test colonies were used to monitor the activity of the tagged bees for the duration of the 5-wk flowering period of the crop. These activity data were analyzed to assess any impact on flight activity of bees foraging on the treated compared with untreated crops. Honeybees were seen to be actively foraging within all 3 treatment groups during the exposure period. The data for the more than 3000 RFID-tagged bees and more than 90 000 foraging flights monitored throughout the exposure phase for the study follow the same trends across the treatment and controls and at each of the 3 apiary distances, indicating that there were no effects from foraging on the treated crop. Under the experimental conditions, there was no effect of foraging on thiamethoxam-treated oilseed rape on honeybee flight activity or on their ability to return to the hive. © 2015 SETAC.

Differential responses of seabirds to environmental variability over 2 years in the continental shelf and oceanic habitats of southeastern Bering Sea

NASA Astrophysics Data System (ADS)

Yamamoto, Takashi; Kokubun, Nobuo; Kikuchi, Dale M.; Sato, Nobuhiko; Takahashi, Akinori; Will, Alexis P.; Kitaysky, Alexander S.; Watanuki, Yutaka

2016-04-01

Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI) and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU) to different marine environmental conditions over 2 years. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. Between the study years, winter ice retreated earlier and summer water temperatures were relatively warmer in 2014 compared to those in 2013. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf but showed a relatively higher use of the shelf break and oceanic basin in 2013. The foraging distances from the colony peaked at 250-300 km in 2013 and bimodally at 150-250 and 300-350 km in 2014 for RLKI and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between the years in RLKI but differed in TBMU, showing higher levels of physiological stress incurred by murres in 2013, the year of relatively cooler sea surface temperatures with later sea-ice retreat. δ13N (a proxy of trophic level of prey) did not differ between the years in either RLKI or TBMU. These results suggest that the response of ecosystem dynamics to climate variability in the southeastern Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds relying on those habitats for foraging.

Environmental conditions and prey-switching by a seabird predator impact juvenile salmon survival

USGS Publications Warehouse

Wells, Brian K.; Santora, Jarrod A.; Henderson, Mark J.; Warzybok, Pete; Jahncke, Jaime; Bradley, Russell W.; Huff, David D.; Schroeder, Isaac D.; Nelson, Peter; Field, John C.; Ainley, David G.

2017-01-01

Due to spatio-temporal variability of lower trophic-level productivity along the California Current Ecosystem (CCE), predators must be capable of switching prey or foraging areas in response to changes in environmental conditions and available forage. The Gulf of the Farallones in central California represents a biodiversity hotspot and contains the largest common murre (Uria aalge) colonies along the CCE. During spring, one of the West Coast's most important Chinook salmon (Oncorhynchus tshawytscha) populations out-migrates into the Gulf of the Farallones. We quantify the effect of predation on juvenile Chinook salmon associated with ecosystem-level variability by integrating long-term time series of environmental conditions (upwelling, river discharge), forage species abundance within central CCE, and population size, at-sea distribution, and diet of the common murre. Our results demonstrate common murres typically forage in the vicinity of their offshore breeding sites, but in years in which their primary prey, pelagic young-of-year rockfish (Sebastesspp.), are less available they forage for adult northern anchovies (Engraulis mordax) nearshore. Incidentally, while foraging inshore, common murre consumption of out-migrating juvenile Chinook salmon, which are collocated with northern anchovy, increases and population survival of the salmon is significantly reduced. Results support earlier findings that show timing and strength of upwelling, and the resultant forage fish assemblage, is related to Chinook salmon recruitment variability in the CCE, but we extend those results by demonstrating the significance of top-down impacts associated with these bottom-up dynamics. Our results demonstrate the complexity of ecosystem interactions and impacts between higher trophic-level predators and their prey, complexities necessary to quantify in order to parameterize ecosystem models and evaluate likely outcomes of ecosystem management options.

Environmental conditions and prey-switching by a seabird predator impact juvenile salmon survival

NASA Astrophysics Data System (ADS)

Wells, Brian K.; Santora, Jarrod A.; Henderson, Mark J.; Warzybok, Pete; Jahncke, Jaime; Bradley, Russell W.; Huff, David D.; Schroeder, Isaac D.; Nelson, Peter; Field, John C.; Ainley, David G.

2017-10-01

Due to spatio-temporal variability of lower trophic-level productivity along the California Current Ecosystem (CCE), predators must be capable of switching prey or foraging areas in response to changes in environmental conditions and available forage. The Gulf of the Farallones in central California represents a biodiversity hotspot and contains the largest common murre (Uria aalge) colonies along the CCE. During spring, one of the West Coast's most important Chinook salmon (Oncorhynchus tshawytscha) populations out-migrates into the Gulf of the Farallones. We quantify the effect of predation on juvenile Chinook salmon associated with ecosystem-level variability by integrating long-term time series of environmental conditions (upwelling, river discharge), forage species abundance within central CCE, and population size, at-sea distribution, and diet of the common murre. Our results demonstrate common murres typically forage in the vicinity of their offshore breeding sites, but in years in which their primary prey, pelagic young-of-year rockfish (Sebastes spp.), are less available they forage for adult northern anchovies (Engraulis mordax) nearshore. Incidentally, while foraging inshore, common murre consumption of out-migrating juvenile Chinook salmon, which are collocated with northern anchovy, increases and population survival of the salmon is significantly reduced. Results support earlier findings that show timing and strength of upwelling, and the resultant forage fish assemblage, is related to Chinook salmon recruitment variability in the CCE, but we extend those results by demonstrating the significance of top-down impacts associated with these bottom-up dynamics. Our results demonstrate the complexity of ecosystem interactions and impacts between higher trophic-level predators and their prey, complexities necessary to quantify in order to parameterize ecosystem models and evaluate likely outcomes of ecosystem management options.

Determinants and Outcomes of Decision-Making, Group Coordination and Social Interactions during a Foraging Experiment in a Wild Primate

PubMed Central

Pyritz, Lennart W.; Fichtel, Claudia; Huchard, Elise; Kappeler, Peter M.

2013-01-01

Social animals have to coordinate joint movements to maintain group cohesion, but the latter is often compromised by diverging individual interests. A widespread behavioral mechanism to achieve coordination relies on shared or unshared consensus decision-making. If consensus costs are high, group fission represents an alternative tactic. Exploring determinants and outcomes of spontaneous group decisions and coordination of free-ranging animals is methodologically challenging. We therefore conducted a foraging experiment with a group of wild redfronted lemurs (Eulemur rufifrons) to study decision outcomes, coordination of movements, individual foraging benefits and social interactions in response to the presentation of drinking platforms with varying baiting patterns. Behavioral observations were complemented with data from recordings of motion detector cameras installed at the platforms. The animal's behavior in the experimental conditions was compared to natural group movements. We could not determine the type of consensus decision-making because the group visited platforms randomly. The group fissioned during 23.3% of platform visits, and fissioning resulted in more individuals drinking simultaneously. As under natural conditions, adult females initiated most group movements, but overtaking by individuals of different age and sex classes occurred in 67% of movements to platforms, compared to only 18% during other movements. As a result, individual resource intake at the platforms did not depend on departure position, age or sex, but on arrival order. Aggression at the platforms did not affect resource intake, presumably due to low supplanting rates. Our findings highlight the diversity of coordination processes and related consequences for individual foraging benefits in a primate group living under natural conditions. PMID:23326392

Corn bran versus corn grain at 2 levels of forage: Intake, apparent digestibility, and production responses by lactating dairy cows

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the effect of substituting corn bran (CB) for dried ground corn grain (CG) in the supplement portion of high-forage (HF) and low-forage (LF) diets. Twelve multiparous and 12 primiparous Holsteins were assigned to 4 diets using six 4 x 4 Latin squares with...

Differential responses of seabirds to inter-annual environmental change in the continental shelf and oceanic habitats of southeastern Bering Sea

NASA Astrophysics Data System (ADS)

Yamamoto, T.; Kokubun, N.; Kikuchi, D. M.; Sato, N.; Takahashi, A.; Will, A.; Kitaysky, A. S.; Watanuki, Y.

2015-11-01

Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI) and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU) to the inter-annual change in environmental conditions. Between the study years, winter ice retreated earlier and summer water temperatures were warmer in 2014 compared to those in 2013. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf, but showed a relatively higher use of the shelf break and oceanic basin in the colder year, 2013. The foraging distances from the colony peaked at 250-300 km in 2013 and, bimodally, at 150-250 and 300-350 km in 2014 for RLKI, and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between years in RLKI, but differed in TBMU, showing higher levels of physiological stress incurred by murres during the colder year, 2013. δ13N (a proxy of trophic level of prey) did not differ between the years in either RLKI or TBMU, while δ13C (a proxy of prey origin) were lower in 2014 than in 2013 in both species, suggesting possible differences in influx of oceanic prey items into foraging areas. These results suggest that the response of ecosystem dynamics to climate variability in the southeast Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds relying on those habitats for foraging.

Feeding-Related Traits Are Affected by Dosage of the foraging Gene in Drosophila melanogaster

PubMed Central

Allen, Aaron M.; Anreiter, Ina; Neville, Megan C.; Sokolowski, Marla B.

2017-01-01

Nutrient acquisition and energy storage are critical parts of achieving metabolic homeostasis. The foraging gene in Drosophila melanogaster has previously been implicated in multiple feeding-related and metabolic traits. Before foraging’s functions can be further dissected, we need a precise genetic null mutant to definitively map its amorphic phenotypes. We used homologous recombination to precisely delete foraging, generating the for0 null allele, and used recombineering to reintegrate a full copy of the gene, generating the {forBAC} rescue allele. We show that a total loss of foraging expression in larvae results in reduced larval path length and food intake behavior, while conversely showing an increase in triglyceride levels. Furthermore, varying foraging gene dosage demonstrates a linear dose-response on these phenotypes in relation to foraging gene expression levels. These experiments have unequivocally proven a causal, dose-dependent relationship between the foraging gene and its pleiotropic influence on these feeding-related traits. Our analysis of foraging’s transcription start sites, termination sites, and splicing patterns using rapid amplification of cDNA ends (RACE) and full-length cDNA sequencing, revealed four independent promoters, pr1–4, that produce 21 transcripts with nine distinct open reading frames (ORFs). The use of alternative promoters and alternative splicing at the foraging locus creates diversity and flexibility in the regulation of gene expression, and ultimately function. Future studies will exploit these genetic tools to precisely dissect the isoform- and tissue-specific requirements of foraging’s functions and shed light on the genetic control of feeding-related traits involved in energy homeostasis. PMID:28007892

Caffeinated forage tricks honeybees into increasing foraging and recruitment behaviors.

PubMed

Couvillon, Margaret J; Al Toufailia, Hasan; Butterfield, Thomas M; Schrell, Felix; Ratnieks, Francis L W; Schürch, Roger

2015-11-02

In pollination, plants provide food reward to pollinators who in turn enhance plant reproduction by transferring pollen, making the relationship largely cooperative; however, because the interests of plants and pollinators do not always align, there exists the potential for conflict, where it may benefit both to cheat the other [1, 2]. Plants may even resort to chemistry: caffeine, a naturally occurring, bitter-tasting, pharmacologically active secondary compound whose main purpose is to detract herbivores, is also found in lower concentrations in the nectar of some plants, even though nectar, unlike leaves, is made to be consumed by pollinators. [corrected]. A recent laboratory study showed that caffeine may lead to efficient and effective foraging by aiding honeybee memory of a learned olfactory association [4], suggesting that caffeine may enhance bee reward perception. However, without field data, the wider ecological significance of caffeinated nectar remains difficult to interpret. Here we demonstrate in the field that caffeine generates significant individual- and colony-level effects in free-flying worker honeybees. Compared to a control, a sucrose solution with field-realistic doses of caffeine caused honeybees to significantly increase their foraging frequency, waggle dancing probability and frequency, and persistency and specificity to the forage location, resulting in a quadrupling of colony-level recruitment. An agent-based model also demonstrates how caffeine-enhanced foraging may reduce honey storage. Overall, caffeine causes bees to overestimate forage quality, tempting the colony into sub-optimal foraging strategies, which makes the relationship between pollinator and plant less mutualistic and more exploitative. VIDEO ABSTRACT. Copyright © 2015 Elsevier Ltd. All rights reserved.

Food searching behaviour of a Lepidoptera pest species is modulated by the foraging gene polymorphism.

PubMed

Chardonnet, Floriane; Capdevielle-Dulac, Claire; Chouquet, Bastien; Joly, Nicolas; Harry, Myriam; Le Ru, Bruno; Silvain, Jean-François; Kaiser, Laure

2014-10-01

The extent of damage to crop plants from pest insects depends on the foraging behaviour of the insect's feeding stage. Little is known, however, about the genetic and molecular bases of foraging behaviour in phytophagous pest insects. The foraging gene (for), a candidate gene encoding a PKG-I, has an evolutionarily conserved function in feeding strategies. Until now, for had never been studied in Lepidoptera, which includes major pest species. The cereal stem borer Sesamia nonagrioides is therefore a relevant species within this order with which to study conservation of and polymorphism in the for gene, and its role in foraging - a behavioural trait that is directly associated with plant injuries. Full sequencing of for cDNA in S. nonagrioides revealed a high degree of conservation with other insect taxa. Activation of PKG by a cGMP analogue increased larval foraging activity, measured by how frequently larvae moved between food patches in an actimeter. We found one non-synonymous allelic variation in a natural population that defined two allelic variants. These variants presented significantly different levels of foraging activity, and the behaviour was positively correlated to gene expression levels. Our results show that for gene function is conserved in this species of Lepidoptera, and describe an original case of a single nucleotide polymorphism associated with foraging behaviour variation in a pest insect. By illustrating how variation in this single gene can predict phenotype, this work opens new perspectives into the evolutionary context of insect adaptation to plants, as well as pest management. © 2014. Published by The Company of Biologists Ltd.

Predator identity and time of day interact to shape the risk-reward trade-off for herbivorous coral reef fishes.

PubMed

Catano, Laura B; Barton, Mark B; Boswell, Kevin M; Burkepile, Deron E

2017-03-01

Non-consumptive effects (NCEs) of predators occur as prey alters their habitat use and foraging decisions to avoid predation. Although NCEs are recognized as being important across disparate ecosystems, the factors influencing their strength and importance remain poorly understood. Ecological context, such as time of day, predator identity, and prey condition, may modify how prey species perceive and respond to risk, thereby altering NCEs. To investigate how predator identity affects foraging of herbivorous coral reef fishes, we simulated predation risk using fiberglass models of two predator species (grouper Mycteroperca bonaci and barracuda Sphyraena barracuda) with different hunting modes. We quantified how predation risk alters herbivory rates across space (distance from predator) and time (dawn, mid-day, and dusk) to examine how prey reconciles the conflicting demands of avoiding predation vs. foraging. When we averaged the effect of both predators across space and time, they suppressed herbivory similarly. Yet, they altered feeding differently depending on time of day and distance from the model. Although feeding increased strongly with increasing distance from the predators particularly during dawn, we found that the barracuda model suppressed herbivory more strongly than the grouper model during mid-day. We suggest that prey hunger level and differences in predator hunting modes could influence these patterns. Understanding how context mediates NCEs provides insight into the emergent effects of predator-prey interactions on food webs. These insights have broad implications for understanding how anthropogenic alterations to predator abundances can affect the spatial and temporal dynamics of important ecosystem processes.

Sympatric Masticophis flagellum and Coluber constrictor select vertebrate prey at different levels of taxonomy

USGS Publications Warehouse

Halstead, B.J.; Mushinsky, H.R.; McCoy, E.D.

2008-01-01

Masticophis flagellum (Coachwhip) and Coluber constrictor (Eastern Racer) are widespread North American snakes with similar foraging modes and habits. Little is known about the selection of prey by either species, and despite their apparently similar foraging habits, comparative studies of the foraging ecology of sympatric M. flagellum and C. constrictor are lacking. We examined the foraging ecology and prey selection of these actively foraging snakes in xeric, open-canopied Florida scrub habitat by defining prey availability separately for each snake to elucidate mechanisms underlying geographic, temporal, and interspecific variation in predator diets. Nineteen percent of M. flagellum and 28% of C. constrictor contained stomach contents, and most snakes contained only one prey item. Mean relative prey mass for both species was less than 10%. Larger C. constrictor consumed larger prey than small individuals, but this relationship disappeared when prey size was scaled to snake size. Masticophis flagellum was selective at the prey category level, and positively selected lizards and mammals; however, within these categories it consumed prey species in proportion to their availability. In contrast, C. constrictor preyed upon prey categories opportunistically, but was selective with regard to species. Specifically, C. constrictor positively selected Hyla femoralis (Pine Woods Treefrog) and negatively selected Bufo querclcus (Oak Toad), B. terrestris (Southern Toad), and Gastrophryne carolinensis (Eastern Narrowmouth Toad). Thus, despite their similar foraging habits, M. flagellum and C. constrictor select different prey and are selective of prey at different levels of taxonomy. ?? 2008 by the American Society of Ichthyologists and Herpetologists.

Coral reef fish predator maintains olfactory acuity in degraded coral habitats.

PubMed

Natt, Michael; Lönnstedt, Oona M; McCormick, Mark I

2017-01-01

Coral reefs around the world are rapidly degrading due to a range of environmental stressors. Habitat degradation modifies the sensory landscape within which predator-prey interactions occur, with implications for olfactory-mediated behaviours. Predator naïve settlement-stage damselfish rely on conspecific damage-released odours (i.e., alarm odours) to inform risk assessments. Yet, species such as the Ambon damselfish, Pomacentrus amboinensis, become unable to respond appropriately to these cues when living in dead-degraded coral habitats, leading to increased mortality through loss of vigilance. Reef fish predators also rely on odours from damaged prey to locate, assess prey quality and engage in prey-stealing, but it is unknown whether their responses are also modified by the change to dead-degraded coral habitats. Implications for prey clearly depend on how their predatory counterparts are affected, therefore the present study tested whether olfactory-mediated foraging responses in the dusky dottyback, Pseudochromis fuscus, a common predator of P. amboinensis, were similarly affected by coral degradation. A y-maze was used to measure the ability of Ps. fuscus to detect and move towards odours, against different background water sources. Ps. fuscus were exposed to damage-released odours from juvenile P. amboinensis, or a control cue of seawater, against a background of seawater treated with either healthy or dead-degraded hard coral. Predators exhibited an increased time allocation to the chambers of y-mazes injected with damage-released odours, with comparable levels of response in both healthy and dead-degraded coral treated waters. In control treatments, where damage-released odours were replaced with a control seawater cue, fish showed no increased preference for either chamber of the y-maze. Our results suggest that olfactory-mediated foraging behaviours may persist in Ps. fuscus within dead-degraded coral habitats. Ps. fuscus may consequently gain a sensory advantage over P. amboinensis, potentially altering the outcome of predator-prey interactions.

Bat Response to Differing Fire Severity in Mixed-Conifer Forest California, USA

PubMed Central

Heady, Paul A.; Hayes, John P.; Frick, Winifred F.

2013-01-01

Wildlife response to natural disturbances such as fire is of conservation concern to managers, policy makers, and scientists, yet information is scant beyond a few well-studied groups (e.g., birds, small mammals). We examined the effects of wildfire severity on bats, a taxon of high conservation concern, at both the stand (<1 ha) and landscape scale in response to the 2002 McNally fire in the Sierra Nevada region of California, USA. One year after fire, we conducted surveys of echolocation activity at 14 survey locations, stratified in riparian and upland habitat, in mixed-conifer forest habitats spanning three levels of burn severity: unburned, moderate, and high. Bat activity in burned areas was either equivalent or higher than in unburned stands for all six phonic groups measured, with four groups having significantly greater activity in at least one burn severity level. Evidence of differentiation between fire severities was observed with some Myotis species having higher levels of activity in stands of high-severity burn. Larger-bodied bats, typically adapted to more open habitat, showed no response to fire. We found differential use of riparian and upland habitats among the phonic groups, yet no interaction of habitat type by fire severity was found. Extent of high-severity fire damage in the landscape had no effect on activity of bats in unburned sites suggesting no landscape effect of fire on foraging site selection and emphasizing stand-scale conditions driving bat activity. Results from this fire in mixed-conifer forests of California suggest that bats are resilient to landscape-scale fire and that some species are preferentially selecting burned areas for foraging, perhaps facilitated by reduced clutter and increased post-fire availability of prey and roosts. PMID:23483936

Sediment-induced turbidity impairs foraging performance and prey choice of planktivorous coral reef fishes.

PubMed

Johansen, J L; Jones, G P

2013-09-01

Sedimentation is a substantial threat to aquatic ecosystems and a primary cause of habitat degradation on near-shore coral reefs. Although numerous studies have demonstrated major impacts of sedimentation and turbidity on corals, virtually nothing is known of the sensitivity of reef fishes. Planktivorous fishes are an important trophic group that funnels pelagic energy sources into reef ecosystems. These fishes are visual predators whose foraging is likely to be impaired by turbidity, but the threshold for such effects and their magnitude are unknown. This study examined the effect of sediment-induced turbidity on foraging in four species of planktivorous damselfishes (Pomacentridae) of the Great Barrier Reef, including inshore and offshore species that potentially differ in tolerance for turbidity. An experimental flow tunnel was used to quantify their ability to catch mobile and immobile planktonic prey under different levels of turbidity and velocity in the range encountered on natural and disturbed reefs. Turbidity of just 4 NTU (nephelometric turbidity units) reduced average attack success by up to 56%, with higher effect sizes for species with offshore distributions. Only the inshore species (Neopomacentrus bankieri), which frequently encounters this turbidity on coastal reefs, could maintain high prey capture success. At elevated turbidity similar to that found on disturbed reefs (8 NTU), attack success was reduced in all species examined by up to 69%. These reductions in attack success led to a 21-24% decrease in foraging rates for all mid to outer-shelf species, in spite of increasing attack rates at high turbidity. Although effects of turbidity varied among species, it always depended heavily on prey mobility and ambient velocity. Attack success was up to 14 times lower on mobile prey, leaving species relatively incapable of foraging on anything but immobile prey at high turbidity. Effects of turbidity were particularly prominent at higher velocities, as attack success was overall 20-fold lower and foraging rates 3.3-fold lower at flow velocities > 30 cm/s relative to < or = 10 cm/s. Given that many planktivorous reef fishes predominantly occupy exposed, high-flow habitats, these results provide a reasonable explanation for the lack of planktivores on inshore coral reefs and warn that the performance of visual predators could be impaired at turbidity levels of only 4 NTU.

Food foraging of honey bees in a microwave field (2. 45 GHz CW)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gary, N.E.; Westerdahl, B.B.

1982-02-15

Honey bees were trained to fly 400 m from their colony to an indoor laboratory foraging arena exposed to 2.45 GHz continuous wave microwaves at 5 power densities (0, 5, 10, 20, and 40 mW/cm/sup 2/). Foraging behavior did not differ from controls foraging within an unexposed sham arena in (1) number of round trips completed during a 3-h exposure session, (2) round trip time between the colony and the foraging arena, and (3) the length of time required to navigate the illuminated foraging arena. This study indicates that honey bees would not be adversely affected by foraging within amore » similar microwave field that would exist in future receiving antennae for the proposed solar power satellite energy transmission system in which power levels are expected to range from 23 mW/cm/sup 2/ at the antenna center to 1 mW/cm/sup 2/ at the edge.« less

Spatial fidelity of workers predicts collective response to disturbance in a social insect.

PubMed

Crall, James D; Gravish, Nick; Mountcastle, Andrew M; Kocher, Sarah D; Oppenheimer, Robert L; Pierce, Naomi E; Combes, Stacey A

2018-04-03

Individuals in social insect colonies cooperate to perform collective work. While colonies often respond to changing environmental conditions by flexibly reallocating workers to different tasks, the factors determining which workers switch and why are not well understood. Here, we use an automated tracking system to continuously monitor nest behavior and foraging activity of uniquely identified workers from entire bumble bee (Bombus impatiens) colonies foraging in a natural outdoor environment. We show that most foraging is performed by a small number of workers and that the intensity and distribution of foraging is actively regulated at the colony level in response to forager removal. By analyzing worker nest behavior before and after forager removal, we show that spatial fidelity of workers within the nest generates uneven interaction with relevant localized information sources, and predicts which workers initiate foraging after disturbance. Our results highlight the importance of spatial fidelity for structuring information flow and regulating collective behavior in social insect colonies.

Foraging modality and plasticity in foraging traits determine the strength of competitive interactions among carnivorous plants, spiders and toads.

PubMed

Jennings, David E; Krupa, James J; Rohr, Jason R

2016-07-01

Foraging modalities (e.g. passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear. Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities. Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited. Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance. These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Magnitude differences in agronomic, chemical, nutritional, and structural features among different varieties of forage corn grown on dry land and irrigated land.

PubMed

Xin, Hangshu; Abeysekara, Samen; Zhang, Xuewei; Yu, Peiqiang

2015-03-11

In this study, eight varieties of corn forage grown in semiarid western Canada (including Pioneer P2501, Pioneer P39m26, Pioneer P7443, Hyland HL3085, Hyland HLBaxxos, Hyland HLR219, Hyland HLSR22, and Pickseed Silex BT) were selected to explore the effect of irrigation implementation in comparison with nonirrigation on (1) agronomic characteristics, (2) basic chemical profiles explored by using a near-infrared reflectance (NIR) system, and (3) protein and carbohydrate internal structural parameters revealed by using an attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) system. Also, principal component analysis (PCA) was performed on spectroscopic data for clarification of differences in molecular structural makeup among the varieties. The results showed that irrigation treatment significantly increased (P < 0.05) contents of dry matter (DM) and organic matter (OM) but decreased crude protein (CP) of corn forages. Significant interactions of irrigation treatment and corn variety were observed on most agronomic characteristics (DM yield, T/ha, days to tasseling, days to silking) and crude fiber (CF) and ether extract (EE) contents as well as some spectral data such as cellulosic compounds (CELC) peak intensity, peak ratios of CHO third peak to CELC, α-helix to β-sheet, and CHO third peak to amide I. Additionally, the spectral ratios of chemical functional groups that related to structural and nonstructural carbohydrates and protein polymers in forages did not remain constant over corn varieties cultivated with and without water treatment. Moreover, different cultivars had different growth, structure, and nutrition performances in this study. Although significant differences could be found in peak intensities, PCA results indicated some structural similarities existed between two treated corn forages with the exception of HL3085 and HLBaxxos. In conclusion, irrigation and corn variety had interaction effects on agronomic, chemical, nutritional, and structural features. Further study on the optimum level of irrigation for corn forage cultivation might be helpful in semiarid regions such as western Canada.

Energy reallocation during and after periods of nutritional stress in Steller sea lions: low-quality diet reduces capacity for physiological adjustments.

PubMed

Jeanniard du Dot, Tiphaine; Rosen, David A S; Trites, Andrew W

2009-01-01

Two groups of female Steller sea lions (groups H and P) were subjected to periods of energy restriction and subsequent refeeding during winter and summer to determine changes in energy partitioning among principal physiological functions and the potential consequences to their fitness. Both sea lion groups consumed high-quality fish (herring) before and after the energy restrictions. During restrictions, group H was fed a lower quantity of herring and group P a caloric equivalent of low-quality fish (pollock). Quantitative estimates of maintenance and production energies and qualitative estimates of thermoregulation, activity, and basal metabolic rate were measured. During summer, all animals compensated for the imposed energy deficit by releasing stored energy (production energy). Group H also optimized the energy allocation to seasonal conditions by increasing activity during summer, when fish are naturally abundant (foraging effort), and by decreasing thermoregulation capacity when waters are warmer. During winter, both groups decreased the energy allocated to overall maintenance functions (basal metabolic rate, thermoregulation, and activity together) in addition to releasing stored energy, but they preserved thermoregulatory capacity. Group H also decreased activity levels in winter, when foraging in the wild is less efficient, unlike group P. Overall, sea lions fed pollock did not change energy allocation to suit environmental conditions as readily as those fed herring. This implies that a low energy-density diet may further reduce fitness of animals in the wild during periods of nutritional stress.

Can schooling regulate marine populations and ecosystems?

NASA Astrophysics Data System (ADS)

Maury, Olivier

2017-08-01

Schools, shoals and swarms are pervasive in the oceans. They have to provide very strong advantages to have been selected and generalized in the course of evolution. Auto-organized groups are usually assumed to provide facilitated encounters of reproduction partners, improved protection against predation, better foraging efficiency, and hydrodynamic gains. However, present theories regarding their evolutionary advantages do not provide an unambiguous explanation to their universality. In particular, the mechanisms commonly proposed to explain grouping provide little support to the formation of very large groups that are common in the sea (e.g. Rieucau et al., 2014). From literature review, data analysis and using a simple mathematical model, I show that large auto-organized groups appear at high population density while only small groups or dispersed individuals remain at low population density. Following, an analysis of tuna tagging data and simple theoretical developments show that large groups are likely to expose individuals to a dramatic decrease of individual foraging success and simultaneous increase of predatory and disease mortality, while small groups avoid those adverse feedbacks and provide maximum foraging success and protection against predation, as it is usually assumed. This would create an emergent density-dependent regulation of marine populations, preventing them from outbursts at high density, and protecting them at low density. This would be a major contribution to their resilience and a crucial process of ecosystems dynamics. A two-step evolutionary process acting at the individual level is proposed to explain how this apparently suicidal behaviour could have been selected and generalized. It explains how grouping would have permitted the emergence of extremely high fecundity life histories, despite their notorious propensity to destabilize populations. The potential implications of the ;grouping feedback; on population resilience, ecosystem stability and the persistence of marine biodiversity are discussed. The risk of harvesting marine species with fishing gears that enable catching dispersed individuals (such as longline, gillnet, trawl or using fishing aggregative devices for instance) is underlined. Finally, tropical tunas are used to exemplify the potential importance of schooling in shaping complex life histories and species interaction.

Estimating Radiological Doses to Predators Foraging in a Low-Level Radioactive Waste Management Area

DOE Office of Scientific and Technical Information (OSTI.GOV)

L.Soholt; G.Gonzales; P.Fresquez

2003-03-01

Since 1957, Los Alamos National Laboratory has operated Area G as its low-level, solid radioactive waste management and disposal area. Although the waste management area is developed, plants, small mammals, and avian and mammalian predators still occupy the less disturbed and revegetated portions of the land. For almost a decade, we have monitored the concentrations of selected radionuclides in soils, plants, and small mammals at Area G. The radionuclides tritium, plutonium-238, and plutonium-239 are regularly found at levels above regional background in all three media. Based on radionuclide concentrations in mice collected from 1994 to 1999, we calculated doses tomore » higher trophic levels (owl, hawk, kestrel, and coyote) that forage on the waste management area. These predators play important functions in the regional ecosystems and are an important part of local Native American traditional tales that identify the uniqueness of their culture. The estimated doses are compared to Department of Energy's interim limit of 0.1 rad/day for the protection of terrestrial wildlife. We used exposure parameters that were derived from the literature for each receptor, including Environmental Protection Agency's exposure factors handbook. Estimated doses to predators ranged from 9E-06 to 2E-04 rad/day, assuming that they forage entirely on the waste management area. These doses are greater than those calculated for predators foraging exclusively in reference areas, but are still well below the interim dose limit. We believe that these calculated doses represent upper-bound estimates of exposure for local predators because the larger predators forage over areas that are much greater than the 63-acre waste management area. Based on these results, we concluded that predators foraging on this area do not face a hazard from radiological exposure under current site conditions.« less

Floral scent in natural hybrids of Ipomopsis (Polemoniaceae) and their parental species

PubMed Central

Bischoff, Mascha; Jürgens, Andreas; Campbell, Diane R.

2014-01-01

Background and Aims Floral traits, such as floral volatiles, can contribute to pre-zygotic reproductive isolation by promoting species-specific pollinator foraging. When hybrid zones form, floral traits could also influence post-zygotic isolation. This study examined floral volatiles in parental species and natural hybrids in order to explore potential scent mediation of pre-zygotic and post-zygotic isolation. Methods Floral bouquets were analysed for the sister species Ipomopsis aggregata and I. tenuituba and their natural hybrids at two contact sites differing in both hybridization rate and temporal foraging pattern of hawkmoth pollinators. Floral volatiles were quantified in diurnal and nocturnal scent samples using gas chromatography–mass spectrometry. Key Results The bouquets of parental species and hybrids showed qualitative overlap. All flowers emitted similar sets of monoterpenoid, sesquiterpenoid, aliphatic and benzenoid compounds, but separated into groups defined by multivariate analysis of quantitative emissions. The parental species differed most strikingly in the nitrogenous compound indole, which was found almost exclusively in nocturnal bouquets of I. tenuituba. Natural hybrid bouquets were highly variable, and showed emission rates of several compounds that appeared transgressive. However, indole emission rates were intermediate in the hybrids compared with rates in the parents. Volatile bouquets at the contact site with lower hybridization did not show greater species specificity in overall scent emission, but I. tenuituba presented a stronger indole signal during peak hawkmoth activity at that site. Conclusions The two species of Ipomopsis differed in patterns of floral bouquets, with indole emitted in nocturnal I. tenuituba, but not in I. aggregata. Natural hybrid bouquets were not consistently intermediate between the parents, although hybrids were intermediate in indole emission. The indole signal could potentially serve as a hawkmoth attractant that mediates reproductive isolation both before and after hybrid formation. PMID:24355404

Experience- and egg-mediated oviposition behaviour in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti)

USDA-ARS?s Scientific Manuscript database

Animals may adapt foraging behavior in variable environments using environmental information. For repeated behaviors such as feeding or reproduction, past experiences can provide this information to guide future decision-making. By changing behavior to be more efficient in an animal’s specific env...

Nest-mediated seed dispersal

Treesearch

Robert J. Warren; Jason P. Love; Mark A. Bradford

2017-01-01

Many plant seeds travel on the wind and through animal ingestion or adhesion; however, an overlooked dispersal mode may lurk within those dispersal modes. Viable seeds may remain attached or embedded within materials birds gather for nest building. Our objective was to determine if birds inadvertently transport seeds when they forage for plant materials to...

Effects of Stage of Lactation and Dietary Forage Level on Body Composition of Alpine Dairy Goats

USDA-ARS?s Scientific Manuscript database

Multiparous Alpine does (42) were used to determine how stage of lactation and dietary forage level affect body composition. Initial measures were made with six does a few days after kidding (0 mo). Before parturition does were fed a 50% concentrate diet free-choice. Eighteen does were fed a 40% ...

Faecal Microbiota of Forage-Fed Horses in New Zealand and the Population Dynamics of Microbial Communities following Dietary Change

PubMed Central

Fernandes, Karlette A.; Kittelmann, Sandra; Rogers, Christopher W.; Gee, Erica K.; Bolwell, Charlotte F.; Bermingham, Emma N.; Thomas, David G.

2014-01-01

The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet (“Group A”; n = 6) or pasture (“Group B”; n = 6) for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S and 18S rRNA gene amplicons were generated and analysed by pyrosequencing. The faecal bacterial communities of both groups of horses were highly diverse (Simpson’s index of diversity >0.8), with differences between the two groups on Day 0 (P<0.017 adjusted for multiple comparisons). There were differences between Groups A and B in the relative abundances of four genera, BF311 (family Bacteroidaceae; P = 0.003), CF231 (family Paraprevotellaceae; P = 0.004), and currently unclassified members within the order Clostridiales (P = 0.003) and within the family Lachnospiraceae (P = 0.006). The bacterial community of Group A horses became similar to Group B within four days of feeding on pasture, whereas the structure of the archaeal community remained constant pre- and post-dietary change. The community structure of the faecal microbiota (bacteria, archaea and ciliate protozoa) of pasture-fed horses was also identified. The initial differences observed appeared to be linked to recent dietary history, with the bacterial community of the forage-fed horses responding rapidly to abrupt dietary change. PMID:25383707

Faecal microbiota of forage-fed horses in New Zealand and the population dynamics of microbial communities following dietary change.

PubMed

Fernandes, Karlette A; Kittelmann, Sandra; Rogers, Christopher W; Gee, Erica K; Bolwell, Charlotte F; Bermingham, Emma N; Thomas, David G

2014-01-01

The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet ("Group A"; n = 6) or pasture ("Group B"; n = 6) for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S and 18S rRNA gene amplicons were generated and analysed by pyrosequencing. The faecal bacterial communities of both groups of horses were highly diverse (Simpson's index of diversity > 0.8), with differences between the two groups on Day 0 (P < 0.017 adjusted for multiple comparisons). There were differences between Groups A and B in the relative abundances of four genera, BF311 (family Bacteroidaceae; P = 0.003), CF231 (family Paraprevotellaceae; P = 0.004), and currently unclassified members within the order Clostridiales (P = 0.003) and within the family Lachnospiraceae (P = 0.006). The bacterial community of Group A horses became similar to Group B within four days of feeding on pasture, whereas the structure of the archaeal community remained constant pre- and post-dietary change. The community structure of the faecal microbiota (bacteria, archaea and ciliate protozoa) of pasture-fed horses was also identified. The initial differences observed appeared to be linked to recent dietary history, with the bacterial community of the forage-fed horses responding rapidly to abrupt dietary change.

Behavioural Repertoires and Time Budgets of Semi-Free-Ranging and Captive Groups of Wedge-Capped Capuchin Monkeys, Cebus olivaceus, in Zoo Exhibits in Venezuela.

PubMed

Tárano, Zaida; López, Marie Charlotte

2015-01-01

The behavioural repertoires and time budgets of 2 captive groups and 1 semi-free-ranging group of Cebus olivaceus were determined with the aim to assess the impact of the zoo environment on behaviour. The repertoires were qualitatively similar between groups and to those reported for wild troops, but the captive groups showed self-directed and stereotyped behaviours not reported in the wild. The differences in repertoires between groups were easily associated with the opportunity to interact directly with the visitors, with particularities of the enclosure and with the severity of confinement. Overall, females spent more time foraging than males in the 2 captive groups, and adults rested and watched more than subadults in all the groups. Time budgets were dominated by foraging, resting, movement and affiliative interactions, but their relative importance varied between groups, with foraging being especially prominent in the most confined group. The time budgets also varied qualitatively from those reported for wild troops. We conclude the species is behaviourally able to adjust to captivity, but the slight differences along the continuum from wild to semi-free to captive are suggestive of mild stress or social tension probably due to unstimulating environmental conditions, high visitor pressure and deviations from typical sex-age group composition.

Source levels of foraging humpback whale calls.

PubMed

Fournet, Michelle E H; Matthews, Leanna P; Gabriele, Christine M; Mellinger, David K; Klinck, Holger

2018-02-01

Humpback whales produce a wide range of low- to mid-frequency vocalizations throughout their migratory range. Non-song "calls" dominate this species' vocal repertoire while on high-latitude foraging grounds. The source levels of 426 humpback whale calls in four vocal classes were estimated using a four-element planar array deployed in Glacier Bay National Park and Preserve, Southeast Alaska. There was no significant difference in source levels between humpback whale vocal classes. The mean call source level was 137 dB RMS re 1 μPa @ 1 m in the bandwidth of the call (range 113-157 dB RMS re 1 μPa @ 1 m), where bandwidth is defined as the frequency range from the lowest to the highest frequency component of the call. These values represent a robust estimate of humpback whale source levels on foraging grounds and should append earlier estimates.

Fidelity and over-wintering of sea turtles.

PubMed

Broderick, Annette C; Coyne, Michael S; Fuller, Wayne J; Glen, Fiona; Godley, Brendan J

2007-06-22

While fidelity to breeding sites is well demonstrated in marine turtles, emerging knowledge of migratory routes and key foraging sites is of limited conservation value unless levels of fidelity can be established. We tracked green (Chelonia mydas, n=10) and loggerhead (Caretta caretta, n=10) turtles during their post-nesting migration from the island of Cyprus to their foraging grounds. After intervals of 2-5 years, five of these females were recaptured at the nesting beach and tracked for a second migration. All five used highly similar migratory routes to return to the same foraging and over-wintering areas. None of the females visited other foraging habitats over the study period (units lasted on average 305 days; maximum, 1356 days), moving only to deeper waters during the winter months where they demonstrated extremely long resting dives of up to 10.2h (the longest breath-holding dive recorded for a marine vertebrate). High levels of fidelity and the relatively discrete nature of the home ranges demonstrate that protection of key migratory pathways, foraging and over-wintering sites can serve as an important tool for the future conservation of marine turtles.

Responses of legumes and grasses to non-, moderate, and dense shade in Missouri, USA. I. Forage yield and its species-level plasticity

Treesearch

Kejia Pang; J.W. Van Sambeek; Nadia E. Navarrete-Tindall; Chung-Ho Lin; Shibu Jose; H. E. Garrett

2017-01-01

Annual screenings of forage grasses and legumes for shade tolerance were conducted from 1996 to 2001 in the outdoor Shade Tolerance Screening Laboratory at the Horticulture and Agroforestry Research Center, University of Missouri. Forty-three forages were grown under non-shade (100% of full sunlight), moderate shade (45%), and dense shade (20%) without competition for...

Climate warming causes life-history evolution in a model for Atlantic cod (Gadus morhua).

PubMed

Holt, Rebecca E; Jørgensen, Christian

2014-01-01

Climate change influences the marine environment, with ocean warming being the foremost driving factor governing changes in the physiology and ecology of fish. At the individual level, increasing temperature influences bioenergetics and numerous physiological and life-history processes, which have consequences for the population level and beyond. We provide a state-dependent energy allocation model that predicts temperature-induced adaptations for life histories and behaviour for the North-East Arctic stock (NEA) of Atlantic cod (Gadus morhua) in response to climate warming. The key constraint is temperature-dependent respiratory physiology, and the model includes a number of trade-offs that reflect key physiological and ecological processes. Dynamic programming is used to find an evolutionarily optimal strategy of foraging and energy allocation that maximizes expected lifetime reproductive output given constraints from physiology and ecology. The optimal strategy is then simulated in a population, where survival, foraging behaviour, growth, maturation and reproduction emerge. Using current forcing, the model reproduces patterns of growth, size-at-age, maturation, gonad production and natural mortality for NEA cod. The predicted climate responses are positive for this stock; under a 2°C warming, the model predicted increased growth rates and a larger asymptotic size. Maturation age was unaffected, but gonad weight was predicted to more than double. Predictions for a wider range of temperatures, from 2 to 7°C, show that temperature responses were gradual; fish were predicted to grow faster and increase reproductive investment at higher temperatures. An emergent pattern of higher risk acceptance and increased foraging behaviour was also predicted. Our results provide important insight into the effects of climate warming on NEA cod by revealing the underlying mechanisms and drivers of change. We show how temperature-induced adaptations of behaviour and several life-history traits are not only mediated by physiology but also by trade-offs with survival, which has consequences for conservation physiology.

Climate warming causes life-history evolution in a model for Atlantic cod (Gadus morhua)

PubMed Central

Holt, Rebecca E.; Jørgensen, Christian

2014-01-01

Climate change influences the marine environment, with ocean warming being the foremost driving factor governing changes in the physiology and ecology of fish. At the individual level, increasing temperature influences bioenergetics and numerous physiological and life-history processes, which have consequences for the population level and beyond. We provide a state-dependent energy allocation model that predicts temperature-induced adaptations for life histories and behaviour for the North-East Arctic stock (NEA) of Atlantic cod (Gadus morhua) in response to climate warming. The key constraint is temperature-dependent respiratory physiology, and the model includes a number of trade-offs that reflect key physiological and ecological processes. Dynamic programming is used to find an evolutionarily optimal strategy of foraging and energy allocation that maximizes expected lifetime reproductive output given constraints from physiology and ecology. The optimal strategy is then simulated in a population, where survival, foraging behaviour, growth, maturation and reproduction emerge. Using current forcing, the model reproduces patterns of growth, size-at-age, maturation, gonad production and natural mortality for NEA cod. The predicted climate responses are positive for this stock; under a 2°C warming, the model predicted increased growth rates and a larger asymptotic size. Maturation age was unaffected, but gonad weight was predicted to more than double. Predictions for a wider range of temperatures, from 2 to 7°C, show that temperature responses were gradual; fish were predicted to grow faster and increase reproductive investment at higher temperatures. An emergent pattern of higher risk acceptance and increased foraging behaviour was also predicted. Our results provide important insight into the effects of climate warming on NEA cod by revealing the underlying mechanisms and drivers of change. We show how temperature-induced adaptations of behaviour and several life-history traits are not only mediated by physiology but also by trade-offs with survival, which has consequences for conservation physiology. PMID:27293671

Adverse foraging conditions may impact body mass and survival of a high Arctic seabird

USGS Publications Warehouse

Harding, A.M.A.; Welcker, J.; Steen, H.; Hamer, K.C.; Kitaysky, A.S.; Fort, J.; Talbot, S.L.; Cornick, L.A.; Karnovsky, N.J.; Gabrielsen, G.W.; Gremillet, D.

2011-01-01

Tradeoffs between current reproduction and future survival are widely recognized, but may only occur when food is limited: when foraging conditions are favorable, parents may be able to reproduce without compromising their own survival. We investigated these tradeoffs in the little auk (Alle alle), a small seabird with a single-egg clutch. During 2005-2007, we examined the relationship between body mass and survival of birds breeding under contrasting foraging conditions at two Arctic colonies. We used corticosterone levels of breeding adults as a physiological indicator of the foraging conditions they encountered during each reproductive season. We found that when foraging conditions were relatively poor (as reflected in elevated levels of corticosterone), parents ended the reproductive season with low body mass and suffered increased post-breeding mortality. A positive relationship between body mass and post-breeding survival was found in one study year; light birds incurred higher survival costs than heavy birds. The results of this study suggest that reproducing under poor foraging conditions may affect the post-breeding survival of long-lived little auks. They also have important demographic implications because even a small change in adult survival may have a large effect on populations of long-lived species. ?? 2011 Springer-Verlag.

Contrasting Patterns of Gene Flow for Amazonian Snakes That Actively Forage and Those That Wait in Ambush.

PubMed

de Fraga, Rafael; Lima, Albertina P; Magnusson, William E; Ferrão, Miquéias; Stow, Adam J

2017-07-01

Knowledge of genetic structure, geographic distance and environmental heterogeneity can be used to identify environmental features and natural history traits that influence dispersal and gene flow. Foraging mode is a trait that might predict dispersal capacity in snakes, because actively foragers typically have greater movement rates than ambush predators. Here, we test the hypothesis that 2 actively foraging snakes have higher levels of gene flow than 2 ambush predators. We evaluated these 4 co-distributed species of snakes in the Brazilian Amazon. Snakes were sampled along an 880 km transect from the central to the southwest of the Amazon basin, which covered a mosaic of vegetation types and seasonal differences in climate. We analyzed thousands of single nucleotide polymorphisms to compare patterns of neutral gene flow based on isolation by geographic distance (IBD) and environmental resistance (IBR). We show that IBD and IBR were only evident in ambush predators, implying lower levels of dispersal than the active foragers. Therefore, gene flow was high enough in the active foragers analyzed here to prevent any build-up of spatial genotypic structure with respect to geographic distance and environmental heterogeneity. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of food availability on serum insulin and lipid concentrations in free-ranging baboons.

PubMed

Kemnitz, Joseph W; Sapolsky, Robert M; Altmann, Jeanne; Muruthi, Philip; Mott, Glen E; Stefanick, Marcia L

2002-05-01

The relationship between food availability and metabolic physiology was studied in groups of free-ranging baboons (Papio spp.) living in the Amboseli National Park and the Masai Mara National Reserve of Kenya. Three groups subsisted entirely on natural forage, while two other groups lived near tourist facilities and often consumed food wastes from these lodges. The refuse provided a very accessible food source with relatively high caloric density. Consumption of the refuse was associated with reduced locomotion. Sexually mature individuals from all five groups were sedated surreptitiously in the early morning and blood samples were collected. Compared to animals foraging exclusively in the wild, animals that supplemented their diet with the refuse items had two- to threefold elevations in serum insulin concentrations, as well as increased total cholesterol (C), HDL-C, and VLDL+LDL-C levels. No sex differences in physiological measures were observed except in body mass. Elevated serum insulin, and cholesterol and lipoprotein concentrations influence the development of cardiovascular disease and have been shown to be subject to dietary manipulation and exercise under controlled conditions. The present results suggest potentially deleterious effects of a highly accessible, calorically dense food source, and associated reduction of physical activity for baboons living in an otherwise natural environment. Copyright 2002 Wiley-Liss, Inc.

Structure and performance of Awassi and Assaf dairy sheep farms in northwestern Spain.

PubMed

Milán, M J; Caja, G; González-González, R; Fernández-Pérez, A M; Such, X

2011-02-01

Data of 69 dairy sheep farms (70% Assaf and 30% Awassi crossbred), located in the Spanish Autonomous Community of Castilla y León and grouped for receiving technical advice, were used to study their structure and performance. Farm surface was 55.4ha, on average. Approximately 25% of the farms did not have cultivation land, and the other 75% had, on average, 73ha (from which 67% were devoted to forage). Farms used 2.1 annual work units (familiar, 90%), 493 ewes, and yielded 147,000 L/yr of milk. Farmers were tenant (84%), younger than 45 yr (70%), had new houses, and were grouped in cooperatives (83%). Sheep were fed indoors (occasional grazing only) in modern loose stalls and had machine milking. Planned mating (summer to fall) was done in 91% of farms (hormonal treatment, 54%) but artificial insemination was scarce (23%). Annual milk sales averaged 309 L/ewe (fat, 6.5%; protein, 5.3%; log(10) somatic cell count, 5.7), and milk was sent to local dairy industries for cheese production, and 1.35 lambs/ewe were harvested as milk-fed lambs (lechazo). Artificial lamb rearing was done in 38% of farms (automatic, 81%; manual, 19%). Total mixed rations were used in 33% of farms, and the rest used rationed concentrate (including self-produced cereals) according to physiological stage of the ewes (0.45 to 1.97 kg/d) and ad libitum forage (dehydrated, 70%; hay, 68%; fresh, 25%; silage, 12%). The concentrate-to-forage ratio ranged between 32 and 61%. In total, 68% of farms bought more than half of the forage, and 87% of them bought more than half of the required concentrates. According to structural, productive, and managerial traits, 4 types of farms were differentiated by using multiple correspondence analysis and cluster analysis. Type groups were: 1) large-surface farms, devoted to cereal and forage production, predominantly with Awassi crossbreed sheep and a high level of self-consumed commodities (12% of the farms); 2) large flocks with intermediate farm surfaces devoted to forage production and predominantly with Assaf sheep (30% of the farms); 3) high-yielding farms, with intermediate sized flocks of Assaf sheep and very intensive management (42% of the farms); and, 4) no-land farms predominantly with Assaf sheep (16% of the farms). In conclusion, the dairy sheep farms studied showed more adoption of intensive production systems than traditional farms, which resulted in higher milk and lamb yields. Despite all of them being based on familiar units, as traditional farms, they were highly dependent on external resources and became more vulnerable, faced with future uncertainties of the market. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effects of cultivar and grazing initiation date on fall-grown oat for replacement dairy heifers.

PubMed

Coblentz, W K; Brink, G E; Esser, N M; Cavadini, J S

2015-09-01

Fall-grown oat has shown promise for extending the grazing season in Wisconsin, but the optimum date for initiating grazing has not been evaluated. Our objectives for this project were (1) to assess the pasture productivity and nutritive value of 2 oat cultivars [Ogle and ForagePlus (OG and FP, respectively)] with late-September (EG) or mid-October (LG) grazing initiation dates; and (2) to evaluate growth performance by heifers grazing these oat forages compared with heifers reared in confinement (CON). A total of 160 gravid Holstein heifers (80 heifers/yr) were assigned to 10 research groups (8 heifers/group). Mean initial body weight was 509±40.5 kg in 2013 and 517±30.2 kg in 2014. Heifer groups were assigned to specific pastures arranged as a 2×2 factorial of oat cultivars and grazing initiation dates. Grazing heifer groups were allowed to strip-graze oat pastures for 6 h daily before returning to the barn, where they were offered a forage-based basal total mixed ration. Main effects of oat cultivar and sampling date interacted for forage characteristics in 2013, but not in 2014. During 2013, oat forage mass increased until early November before declining in response to freezing weather conditions, thereby exhibiting linear and quadratic effects of sampling date, regardless of oat cultivar. Similar trends over time were observed in 2014. For 2013, the maximum forage mass was 5,329 and 5,046 kg/ha for FP and OG, respectively, whereas the mean maximum forage mass for 2014 was 4,806 kg/ha. ForagePlus did not reach the boot stage of growth during either year of the trial; OG matured more rapidly, reaching the late-heading stage during 2013, but exhibited only minor maturity differences from FP in 2014. For 2013, average daily gain for CON did not differ from grazing heifer groups (overall mean=0.63 kg/d); however, average daily gain from FP was greater than OG (0.68 vs. 0.57 kg/d), and greater from EG compared with LG (0.82 vs. 0.43 kg/d). For 2013, advantages in average daily gain for heifers grazing FP pastures were likely related to the greater energy density of FP oat throughout the fall that reached a maximum of 68.8% total digestible nutrients on November 27 compared with only 63.7% for OG on October 10. During 2014, average daily gain from CON exceeded all grazing heifer groups (0.81 vs. 0.57 kg/d), and average daily gain from EG again exceeded LG (0.70 vs. 0.44 kg/d). These results suggest that delaying grazing until mid-October will consistently suppress heifer growth performance, particularly if rapidly maturing cultivars are used. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Nectar loads as fuel for collecting nectar and pollen in honeybees: adjustment by sugar concentration.

PubMed

Harano, Ken-Ichi; Nakamura, Jun

2016-06-01

When honeybee foragers leave the nest, they receive nectar from nest mates for use as fuel for flight or as binding material to build pollen loads. We examined whether the concentration of nectar carried from the nest changes with the need for sugar. We found that pollen foragers had more-concentrated nectar (61.8 %) than nectar foragers (43.8 %). Further analysis revealed that the sugar concentration of the crop load increased significantly with waggle duration, an indicator of food-source distance, in both groups of foragers. Crop volume also increased with waggle duration. The results support our argument that foragers use concentrated nectar when the need for sugar is high and suggest that they precisely adjust the amount of sugar in the crop by altering both volume and nectar concentrations. We also investigated the impact of the area where foragers receive nectar on the crop load concentration at departure. Although nectar and pollen foragers tend to load nectar at different areas in the nest, area did not have a significant effect on crop load concentration. Departing foragers showed an average of 2.2 momentary (<1 s) begging trophallactic contacts before leaving the nest. They might be rejecting nectar with inappropriate concentrations during these contacts.

Distributed leadership and adaptive decision-making in the ant Tetramorium caespitum.

PubMed

Collignon, B; Detrain, C

2010-04-22

In the ant species Tetramorium caespitum, communication and foraging patterns rely on group-mass recruitment. Scouts having discovered food recruit nestmates and behave as leaders by guiding groups of recruits to the food location. After a while, a mass recruitment takes place in which foragers follow a chemical trail. Since group recruitment is crucial to the whole foraging process, we investigated whether food characteristics induce a tuning of recruiting stimuli by leaders that act upon the dynamics and size of recruited groups. High sucrose concentration triggers the exit of a higher number of groups that contain twice as many ants and reach the food source twice as fast than towards a weakly concentrated one. Similar trends were found depending on food accessibility: for a cut mealworm, accessibility to haemolymph results in a faster formation of larger groups than for an entire mealworm. These data provide the background for developing a stochastic model accounting for exploitation patterns by group-mass recruiting species. This model demonstrates how the modulations performed by leaders drive the colony to select the most profitable food source among several ones. Our results highlight how a minority of individuals can influence collective decisions in societies based on a distributed leadership.

Fishing amplifies forage fish population collapses.

PubMed

Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

2015-05-26

Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

Fisheries research and monitoring activities of the Lake Erie Biological Station, 2016

USGS Publications Warehouse

Bodamer Scarbro, Betsy L.; Kraus, Richard T.; Kocovsky, Patrick; Vandergoot, Christopher

2017-01-01

We conducted a biomass-based assessment of the Lake Erie Western Basin fish community using data collected from 2013-2016 Western Basin (spring and autumn) bottom trawl surveys. Biomass of total catch per hectare has decreased 75 percent since 2013. Declines were observed across all functional groups, but most notable was the decline of Emerald Shiner, which decreased from 25.3 kg/ha in spring 2013 to <0.01 kg/ha by autumn 2013. The four primary predator species – Walleye, Yellow Perch, White Perch, and White Bass – all decreased from 2013 to 2015. In 2016, White Bass and Yellow Perch (all lifestages combined) continued to decline, while Walleye and White Perch (all ages combined) increased slightly from 5.6 kg/ha and 3.4 kg/ha to 9.0 kg/ha and 5.0 kg/ha, respectively (autumn catches). Despite decreasing trends in biomass, there was little change in biodiversity. Declines in forage biomass, i.e. Emerald Shiner and age-0 White Perch, resulted in an increased mean trophic level of catches. Forage fish to piscivore ratios reflected marked shifts in species composition toward greater forage in 2014 and 2016.

A Breath of Fresh Air in Foraging Theory: The Importance of Wind for Food Size Selection in a Central-Place Forager.

PubMed

Alma, Andrea Marina; Farji-Brener, Alejandro G; Elizalde, Luciana

2017-09-01

Empirical data about food size carried by central-place foragers do not often fit with the optimum predicted by classical foraging theory. Traditionally, biotic constraints such as predation risk and competition have been proposed to explain this inconsistency, leaving aside the possible role of abiotic factors. Here we documented how wind affects the load size of a central-place forager (leaf-cutting ants) through a mathematical model including the whole foraging process. The model showed that as wind speed at ground level increased from 0 to 2 km/h, load size decreased from 91 to 30 mm 2 , a prediction that agreed with empirical data from windy zones, highlighting the relevance of considering abiotic factors to predict foraging behavior. Furthermore, wind reduced the range of load sizes that workers should select to maintain a similar rate of food intake and decreased the foraging rate by ∼70% when wind speed increased 1 km/h. These results suggest that wind could reduce the fitness of colonies and limit the geographic distribution of leaf-cutting ants. The developed model offers a complementary explanation for why load size in central-place foragers may not fit theoretical predictions and could serve as a basis to study the effects of other abiotic factors that influence foraging.

Multiple-stage decisions in a marine central-place forager

NASA Astrophysics Data System (ADS)

Friedlaender, Ari S.; Johnston, David W.; Tyson, Reny B.; Kaltenberg, Amanda; Goldbogen, Jeremy A.; Stimpert, Alison K.; Curtice, Corrie; Hazen, Elliott L.; Halpin, Patrick N.; Read, Andrew J.; Nowacek, Douglas P.

2016-05-01

Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator-prey interactions and underscores the need to simultaneously measure prey distribution in marine central place forager studies.

Multiple-stage decisions in a marine central-place forager.

PubMed

Friedlaender, Ari S; Johnston, David W; Tyson, Reny B; Kaltenberg, Amanda; Goldbogen, Jeremy A; Stimpert, Alison K; Curtice, Corrie; Hazen, Elliott L; Halpin, Patrick N; Read, Andrew J; Nowacek, Douglas P

2016-05-01

Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator-prey interactions and underscores the need to simultaneously measure prey distribution in marine central place forager studies.

Stingless bees (Melipona scutellaris) learn to associate footprint cues at food sources with a specific reward context.

PubMed

Roselino, Ana Carolina; Rodrigues, André Vieira; Hrncir, Michael

2016-10-01

Foraging insects leave chemical footprints on flowers that subsequent foragers may use as indicators for recent flower visits and, thus, potential resource depletion. Accordingly, foragers should reject food sources presenting these chemical cues. Contrasting this assumption, experimental studies in stingless bees (Apidae, Meliponini), so far, demonstrated an attractive effect of footprints. These findings lead to doubts about the meaning of these chemical cues in natural foraging contexts. Here, we asked whether foragers of stingless bees (Melipona scutellaris) use footprints according to the previously experienced reward level of visited food sources. Bees were trained to artificial flower patches, at which the reward of a flower either decreased or, alternatively, increased after a visit by a forager. Individuals were allowed a total of nine foraging bouts to the patch, after which their preference for visited or unvisited flowers was tested. In the choice tests, bees trained under the decreasing reward context preferred unvisited flowers, whereas individuals trained under the increasing reward context preferred visited flowers. Foragers without experience chose randomly between visited and unvisited flowers. These results demonstrate that M. scutellaris learns to associate unspecific footprint cues at food sources with differential, specific reward contexts, and uses these chemical cues accordingly for their foraging decisions.

Supplementing a ruminally undegradable protein supplement to maintain essential amino acid supply to the small intestine when forage intake is restricted in beef cattle.

PubMed

Scholljegerdes, E J; Weston, T R; Ludden, P A; Hess, B W

2005-09-01

Twelve Angus crossbred cattle (eight heifers and four steers; average initial BW = 594 +/- 44.4 kg) fitted with ruminal and duodenal cannulas and fed restricted amounts of forage plus a ruminally undegradable protein (RUP) supplement were used in a triplicated 4 x 4 Latin square design experiment to determine intestinal supply of essential AA. Cattle were fed four different levels of chopped (2.54 cm) bromegrass hay (11.4% CP, 57% NDF; OM basis): 30, 55, 80, or 105% of the forage intake required for maintenance. Cattle fed below maintenance were given specified quantities of a RUP supplement (6.8% porcine blood meal, 24.5% hydrolyzed feather meal, and 68.7% menhaden fish meal; DM basis) designed to provide duodenal essential AA flow equal to that of cattle fed forage at 105% of maintenance. Experimental periods lasted 21 d (17 d of adaptation and 4 d of sampling). Total OM intake and duodenal OM flow increased linearly (P < 0.001) as cattle consumed more forage; however, OM truly digested in the rumen (% of intake) did not change (P = 0.43) as intake increased. True ruminal N degradation (% of intake) tended (P = 0.07) to increase linearly, and true ruminal N degradation (g/d) decreased quadratically (P = 0.02) as intake increased from 30 to 105%. Duodenal N flow was equal (P = 0.33) across intake levels, even though microbial N flow increased linearly (P < 0.001) as forage OM intake increased. Total and individual essential AA intake decreased (cubic; P < 0.001) as forage intake increased because the supply of nonammonia, nonmicrobial N flow from RUP was decreased (linear; P < 0.001) by design. Total duodenal flow of essential AA did not differ (P = 0.39) across these levels of forage intake. Although the profile of essential AA reaching the duodenum differed (P < or = 0.02) for all 10 essential AA, the range of each essential AA as a proportion of total essential AA was low (11.1 to 11.2% of total essential AA for phenylalanine to 12.3 to 14.3% of total essential AA for lysine). Duodenal essential AA flow did not differ (P = 0.10 to 0.65) with forage intake level for eight of the 10 essential AA. Duodenal flow of arginine decreased linearly (P = 0.01), whereas duodenal flow of tryptophan increased linearly (P = 0.002) as forage intake increased from 30 to 105% of maintenance. Balancing intestinal essential AA supply in beef cattle can be accomplished by varying intake of a RUP supplement.

Balancing personal maintenance with parental investment in a chick-rearing seabird: physiological indicators change with foraging conditions.

PubMed

Storey, Anne E; Ryan, Morag G; Fitzsimmons, Michelle G; Kouwenberg, Amy-Lee; Takahashi, Linda S; Robertson, Gregory J; Wilhelm, Sabina I; McKay, Donald W; Herzberg, Gene R; Mowbray, Frances K; MacMillan, Luke; Walsh, Carolyn J

2017-01-01

Seabird parents use a conservative breeding strategy that favours long-term survival over intensive parental investment, particularly under harsh conditions. Here, we examine whether variation in several physiological indicators reflects the balance between parental investment and survival in common murres ( Uria aalge ) under a wide range of foraging conditions. Blood samples were taken from adults during mid-chick rearing from 2007 to 2014 and analysed for corticosterone (CORT, stress hormone), beta-hydroxybutyrate (BUTY, lipid metabolism reflecting ongoing mass loss), and haematocrit (reflecting blood oxygen capacity). These measures, plus body mass, were related to three levels of food availability (good, intermediate, and poor years) for capelin, the main forage fish for murres in this colony. Adult body mass and chick-feeding rates were higher in good years than in poor years and heavier murres were more likely to fledge a chick than lighter birds. Contrary to prediction, BUTY levels were higher in good years than in intermediate and poor years. Murres lose body mass just after their chicks hatch and these results for BUTY suggest that mass loss may be delayed in good years. CORT levels were higher in intermediate years than in good or poor years. Higher CORT levels in intermediate years may reflect the necessity of increasing foraging effort, whereas extra effort is not needed in good years and it is unlikely to increase foraging success in poor years. Haematocrit levels were higher in poor years than in good years, a difference that may reflect either their poorer condition or increased diving requirements when food is less available. Our long-term data set provided insight into how decisions about resource allocation under different foraging conditions are relating to physiological indicators, a relationship that is relevant to understanding how seabirds may respond to changes in marine ecosystems as ocean temperatures continue to rise.

Sexual segregation in Roosevelt Elk: Cropping rates and aggression in mixed sex groups

USGS Publications Warehouse

Weckerly, Floyd F.; Ricca, Mark A.; Meyer, Katherin P.

2001-01-01

Few studies of sexual segregation in ruminants have tested widely invoked mechanisms of segregation in mixed-sex groups. In a sexually segregated population of Roosevelt elk (Cervus elaphus roosevelti), we examined if adult males had reduced intake of forage when in mixed-sex groups and if intersexual differences in aggression caused females to avoid males. Based on a mechanistic model of forage intake, animals with lower instantaneous feed intake should have higher cropping rates. Focal animal sampling indicated that adult males and females in summer and winter had similar cropping rates in mixed-sex groups, whereas males in male-only groups had lower rates of cropping than males in mixed-sex groups. Outside the mating season, males in male groups spent proportionally less time ≤1 body length of congenders than females in female groups, and the rate of aggression ≤1 body length was higher for males. Female–female aggression was higher in mixed-sex groups that contained more males than the median proportion of males in mixed-sex groups. Female and mixed-sex groups walked away when groups of males numbering >6 were ≤50 m but did not walk away when male groups ≤50 m had ≤5 individuals. Sexual segregation was associated with behaviors of sexes in mixed-sex groups: reduced intake of forage by males and increased female–female aggression with more males.

Mastracchio works with the Ant Forage Habitat Facility

NASA Image and Video Library

2014-01-13

ISS038-E-031992 (13 Jan. 2014) --- NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, works with the Ant Forage Habitat Facility in the Destiny laboratory of the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

Effects of alfalfa hay and its physical form (chopped versus pelleted) on performance of Holstein calves.

PubMed

Jahani-Moghadam, M; Mahjoubi, E; Hossein Yazdi, M; Cardoso, F C; Drackley, J K

2015-06-01

Inclusion of forage and its physical form in starter may affect rumen development, average daily gain (ADG), and dry matter intake (DMI) of dairy calves. To evaluate the effects of forage and its physical form (chopped vs. pelleted) on growth of calves under a high milk feeding regimen, 32 Holstein calves (38.8±1.1kg) were assigned at birth to 1 of 3 treatments in a completely randomized block design. Dietary treatments (% of dry matter) were (1) 100% semi-texturized starter (CON); (2) 90% semi-texturized starter + 10% chopped alfalfa hay (mean particle size=5.4mm) as a total mixed ration (TMR; CH); and (3) 90% semi-texturized starter + 10% pelleted alfalfa (mean=5.8mm) hay as a TMR (PH). Data were subjected to mixed model analysis with contrasts used to evaluate effect of forage inclusion. Calves were weaned at 76 d of age and the experiment finished 2 wk after weaning. Individual milk and solid feed consumption were recorded daily. Solid feed consumption and ADG increased as age increased (effect of week), but neither forage inclusion nor physical form of forage affected these variables pre- or postweaning. Plasma urea N was affected by treatments such that the CON group had a lower concentration than forage-fed groups. Forage inclusion, but not physical form, resulted in increased total protein in plasma. Although days with elevated rectal temperature, fecal score, and general appearance were not affected by dietary treatments, calves fed alfalfa hay during the first month of life had fewer days with respiratory issues, regardless of physical form of hay. We concluded that provision of forage does have some beneficial effects in calves fed large amounts of milk replacer, but pelleted alfalfa hay did not result in any improvement in calf performance or health. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Social Differentiation in Common Bottlenose Dolphins (Tursiops truncatus) that Engage in Human-Related Foraging Behaviors

PubMed Central

2017-01-01

Both natural and human-related foraging strategies by the common bottlenose dolphin (Tursiops truncatus) have resulted in social segregation in several areas of the world. Bottlenose dolphins near Savannah, Georgia beg at an unprecedented rate and also forage behind commercial shrimp trawlers, providing an opportunity to study the social ramifications of two human-related foraging behaviors within the same group of animals. Dolphins were photo-identified via surveys conducted throughout estuarine waterways around Savannah in the summers of 2009–2011. Mean half-weight indices (HWI) were calculated for each foraging class, and community division by modularity was used to cluster animals based on association indices. Pairs of trawler dolphins had a higher mean HWI (0.20 ± 0.07) than pairs of non-trawler dolphins (0.04 ± 0.02) or mixed pairs (0.02 ± 0.02). In contrast, pairs of beggars, non-beggars, and mixed pairs all had similar means, with HWI between 0.05–0.07. Community division by modularity produced a useful division (0.307) with 6 clusters. Clusters were predominately divided according to trawler status; however, beggars and non-beggars were mixed throughout clusters. Both the mean HWI and social clusters revealed that the social structure of common bottlenose dolphins near Savannah, Georgia was differentiated based on trawler status but not beg status. This finding may indicate that foraging in association with trawlers is a socially learned behavior, while the mechanisms for the propagation of begging are less clear. This study highlights the importance of taking into account the social parameters of a foraging behavior, such as how group size or competition for resources may affect how the behavior spreads. The positive or negative ramifications of homophily may influence whether the behaviors are exhibited by individuals within the same social clusters and should be considered in future studies examining social relationships and foraging behaviors. PMID:28146563

Rescue of newborn ants by older Cataglyphis cursor adult workers.

PubMed

Nowbahari, Elise; Amirault, Céline; Hollis, Karen L

2016-05-01

Cataglyphis cursor worker ants are capable of highly sophisticated rescue behaviour in which individuals are able to identify what has trapped a nestmate and to direct their behaviour towards that obstacle. Nonetheless, rescue behaviour is constrained by workers' subcaste: whereas foragers, the oldest workers, are able both to give and to receive the most help, the youngest workers, inactives, neither give nor receive any help whatsoever; nurses give and receive intermediate levels of aid, reflecting their intermediate age. Such differences in rescue behaviour across subcastes suggest that age and experience play a critical role. In this species, as in many others in which a sensitive period for nestmate recognition exists, newly enclosed ants, called callows, are adopted by ants belonging not only to different colonies but also to different species; foreign callows receive nearly the same special care provided to resident newborns. Because callows are younger than inactives, which are incapable of soliciting rescue, we wondered whether entrapped callows would receive such aid. In the present study, we artificially ensnared individual callows from their own colony (homocolonial), from a different colony (heterocolonial), and from a different species (heterospecific), and tested each one with groups of five potential C. cursor rescuers, either all foragers or all nurses. Our results show that all three types of callows are able to elicit rescue behaviour from both foragers and nurses. Nonetheless, nurse rescuers are better able to discriminate between the three types of callow victims than are foragers.

Seasonal assessment of selenium as a hazardous element in pasture and animal system: a case study of Kajli sheep in Sargodha, Pakistan.

PubMed

Khan, Zafar Iqbal; Ashraf, Muhammad; Ahmad, Kafeel; Al-Qurainy, F

2010-07-15

Grazing Kajli Pakistani sheep (30 in number) with mean body weight of 35 kg and of 36 months old were investigated to evaluate seasonal influence on Se levels of three different sheep classes including lactating and non-lactating ewes and male sheep. Samples of forage and blood were obtained four times after one month interval during summer and winter seasons and these were analyzed to assess the Se contents. Forage Se content was higher in winter than that in summer, while the reverse was true during summer. Blood plasma Se contents were higher in summer, particularly in male sheep compared to those in lactating and non lactating ewes. High incidence of deficiency was found in lactating ewes compared to the other groups of animal. The plasma concentrations of all sheep classes were found in the acceptable range required for normal metabolism and reproduction. Although there is no urgent need for supplementing the animals with mineral mixture with higher availability of selenium, forage plants and lactating sheep in some instances were found deficient in Se during this investigation, therefore, their low Se concentrations may pose a threat for grazing ruminants at this livestock farm. So, a Se supplementation in the form of forages with high Se contents or mineral mixture is required at this animal ranch to prevent the potential hazards of Se deficiency. 2010 Elsevier B.V. All rights reserved.

Integrating feeding behavior, ecological data, and DNA barcoding to identify developmental differences in invertebrate foraging strategies in wild white-faced capuchins (Cebus capucinus).

PubMed

Mallott, Elizabeth K; Garber, Paul A; Malhi, Ripan S

2017-02-01

Invertebrate foraging strategies in nonhuman primates often require complex extractive foraging or prey detection techniques. As these skills take time to master, juveniles may have reduced foraging efficiency or concentrate their foraging efforts on easier to acquire prey than adults. We use DNA barcoding, behavioral observations, and ecological data to assess age-based differences in invertebrate prey foraging strategies in a group of white-faced capuchins (Cebus capucinus) in northeastern Costa Rica. Invertebrate availability was monitored using canopy traps and sweep netting. Fecal samples were collected from adult female, adult male, and juvenile white-faced capuchins (n = 225). COI mtDNA sequences were compared with known sequences in GenBank and the Barcode of Life Database. Frequencies of Lepidoptera and Hymenoptera consumption were higher in juveniles than in adults. A significantly smaller proportion of juvenile fecal samples contained Gryllidae and Cercopidae sequences, compared with adults (0% and 4.2% vs. 4.6% and 12.5%), and a significantly larger proportion contained Tenthredinidae, Culicidae, and Crambidae (5.6%, 9.7%, and 5.6% vs. 1.3%, 0.7%, and 1.3%). Juveniles spent significantly more time feeding and foraging than adults, and focused their foraging efforts on prey that require different skills to capture or extract. Arthropod availability was not correlated with foraging efficiency, and the rate of consumption of specific orders of invertebrates was not correlated with the availability of those same taxa. Our data support the hypothesis that juveniles are concentrating their foraging efforts on different prey than adults, potentially focusing their foraging efforts on more easily acquired types of prey. © 2016 Wiley Periodicals, Inc.

Responses of legumes and grasses to non-, moderate, and dense shade in Missouri, USA. II. Forage quality and its species-level plasticity

Treesearch

Kejia Pang; J.W. Van Sambeek; Nadia E. Navarrete-Tindall; Chung-Ho Lin; Shibu Jose; H. E. Garrett

2017-01-01

From a series of shade tolerance screening trials conducted in an outdoor Shade Tolerance Screening Laboratory, 22 forages (16 grasses and 6 legumes) were selected for quality evaluation. The forages were grown under non-shade (100% of full sun, the control), moderate shade (45%), and dense shade (20%) with adequate water and nutrients and free of competition from...

Influence of Soil Properties on Soldierless Termite Distribution.

PubMed

Bourguignon, Thomas; Drouet, Thomas; Šobotník, Jan; Hanus, Robert; Roisin, Yves

2015-01-01

In tropical rainforests, termites constitute an important part of the soil fauna biomass, and as for other soil arthropods, variations in soil composition create opportunities for niche partitioning. The aim of this study was twofold: first, we tested whether soil-feeding termite species differ in the foraging substrate; second, we investigated whether soil-feeding termites select their foraging sites to enhance nutrients intake. To do so, we collected termites and analysed the composition and structure of their feeding substrates. Although Anoplotermes-group members are all considered soil-feeders, our results show that some species specifically feed on abandoned termite nests and very rotten wood, and that this substrate selection is correlated with previous stable isotope analyses, suggesting that one component of niche differentiation among species is substrate selection. Our results show that the composition and structure of bare soils on which different termite species foraged do not differ, suggesting that there is no species specialization for a particular type of bare soil. Finally, the bare soil on which termites forage does not differ from random soil samples. Overall, our results suggest that few species of the Anoplotermes-group are specialized toward substrates rich in organic matter, but that the vast majority forage on soil independently of its structural and chemical composition, being ecologically equivalent for this factor.

Maternal hypothalamic-pituitary-adrenal axis response to foraging uncertainty: A model of individual vs. social allostasis and the "Superorganism Hypothesis"

PubMed Central

Coplan, Jeremy D.; Karim, Asif; Rozenboym, Anna; Smith, Eric L. P.; Kral, John G.; Rosenblum, Leonard A.

2017-01-01

Introduction Food insecurity is a major global contributor to developmental origins of adult disease. The allostatic load of maternal food uncertainty from variable foraging demand (VFD) activates corticotropin-releasing factor (CRF) without eliciting hypothalamic-pituitary-adrenal (HPA) activation measured on a group level. Individual homeostatic adaptations of the HPA axis may subserve second-order homeostasis, a process we provisionally term “social allostasis.” We postulate that maternal food insecurity induces a “superorganism” state through coordination of individual HPA axis response. Methods Twenty-four socially-housed bonnet macaque maternal-infant dyads were exposed to 16 weeks of alternating two-week epochs of low or high foraging demand shown to compromise normative maternal-infant rearing. Cerebrospinal fluid (CSF) CRF concentrations and plasma cortisol were measured pre- and post-VFD. Dyadic distance was measured, and blinded observers performed pre-VFD social ranking assessments. Results Despite marked individual cortisol responses (mean change = 20%) there was an absence of maternal HPA axis group mean response to VFD (0%). Whereas individual CSF CRF concentrations change = 56%, group mean did increase 25% (p = 0.002). Our "dyadic vulnerability" index (low infant weight, low maternal weight, subordinate maternal social status and reduced dyadic distance) predicted maternal cortisol decreases (p < 0.0001) whereas relatively “advantaged” dyads exhibited maternal cortisol increases in response to VFD exposure. Comment In response to a chronic stressor, relative dyadic vulnerability plays a significant role in determining the directionality and magnitude of individual maternal HPA axis responses in the service of maintaining a “superorganism” version of HPA axis homeostasis, provisionally termed “social allostasis.” PMID:28880949

Harvest-related edge effects on prey availability and foraging of hooded warblers in a bottomland hardwood forest.

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Kilgo

2005-04-20

The effects of harvest-created canopy gaps in bottomland hardwood forests on arthropod abundance and, hence, the foraging ecology of birds are poorly understood. I predicted that arthropod abundance would be high near edges of group-selection harvest gaps and lower in the surrounding forest, and that male Hooded Warblers (Wilsonia citrina) foraging near gaps would find more prey per unit time than those foraging in the surrounding forest. In fact, arthropod abundance was greater >100 m from a gap edge than at 0-30 m or 30-100 m from an edge, due to their abundance on switchcane (Arundinaria gigantea); arthropods did notmore » differ in abundance among distances from gaps on oaks (Quercus spp.) or red maple (Acer rubrum). Similarly, Hooded Warbler foraging attack rates were not higher near gap edges: when foraging for fledglings, attack rate did not differ among distances from gaps, but when foraging for themselves, attack rates actually were lower 0-30 m from gap edges than 30-100 m or >100 m from a gap edge. Foraging attack rate was positively associated with arthropod abundance. Hooded Warblers apparently encountered fewer prey and presumably foraged less efficiently where arthropods were least abundant, i.e., near gaps. That attack rates among birds foraging for fledglings were not affected by distance from gap (and hence arthropod abundance) suggests that prey availability may not be limiting at any location across the forest, despite the depressing effects of gaps on arthropod abundance.« less

Fitness consequences of spousal relatedness in 46 small-scale societies.

PubMed

Bailey, Drew H; Hill, Kim R; Walker, Robert S

2014-05-01

Social norms that regulate reproductive and marital decisions generate impressive cross-cultural variation in the prevalence of kin marriages. In some societies, marriages among kin are the norm and this inbreeding creates intensive kinship networks concentrated within communities. In others, especially forager societies, most marriages are between more genealogically and geographically distant individuals, which generates a larger number of kin and affines of lesser relatedness in more extensive kinship networks spread out over multiple communities. Here, we investigate the fitness consequence of kin marriages across a sample of 46 small-scale societies (12,439 marriages). Results show that some non-forager societies (including horticulturalists, agriculturalists and pastoralists), but not foragers, have intensive kinship societies where fitness outcomes (measured as the number of surviving children in genealogies) peak at commonly high levels of spousal relatedness. By contrast, the extensive kinship systems of foragers have worse fitness outcomes at high levels of spousal relatedness. Overall, societies with greater levels of inbreeding showed a more positive relationship between fitness and spousal relatedness. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Large pollen loads of a South African asclepiad do not interfere with the foraging behaviour or efficiency of pollinating honey bees

NASA Astrophysics Data System (ADS)

Coombs, G.; Dold, A. P.; Brassine, E. I.; Peter, C. I.

2012-07-01

The pollen of asclepiads (Asclepiadoideae, Apocynaceae) and most orchids (Orchidaceae) are packaged as large aggregations known as pollinaria that are removed as entire units by pollinators. In some instances, individual pollinators may accumulate large loads of these pollinaria. We found that the primary pollinator of Cynanchum ellipticum (Apocynaceae—Asclepiadoideae), the honey bee Apis mellifera, accumulate very large agglomerations of pollinaria on their mouthparts when foraging on this species. We tested whether large pollinarium loads negatively affected the foraging behaviour and foraging efficiency of honey bees by slowing foraging speeds or causing honey bees to visit fewer flowers, and found no evidence to suggest that large pollinarium loads altered foraging behaviour. C. ellipticum displayed consistently high levels of pollination success and pollen transfer efficiency (PTE). This may be a consequence of efficiently loading large numbers of pollinaria onto pollinators even when primary points of attachment on pollinators are already occupied and doing so in a manner that does not impact the foraging behaviour of pollinating insects.

Thigmotaxis Mediates Trail Odour Disruption.

PubMed

Stringer, Lloyd D; Corn, Joshua E; Sik Roh, Hyun; Jiménez-Pérez, Alfredo; Manning, Lee-Anne M; Harper, Aimee R; Suckling, David M

2017-05-10

Disruption of foraging using oversupply of ant trail pheromones is a novel pest management application under investigation. It presents an opportunity to investigate the interaction of sensory modalities by removal of one of the modes. Superficially similar to sex pheromone-based mating disruption in moths, ant trail pheromone disruption lacks an equivalent mechanistic understanding of how the ants respond to an oversupply of their trail pheromone. Since significant compromise of one sensory modality essential for trail following (chemotaxis) has been demonstrated, we hypothesised that other sensory modalities such as thigmotaxis could act to reduce the impact on olfactory disruption of foraging behaviour. To test this, we provided a physical stimulus of thread to aid trailing by Argentine ants otherwise under disruptive pheromone concentrations. Trail following success was higher using a physical cue. While trail integrity reduced under continuous over-supply of trail pheromone delivered directly on the thread, provision of a physical cue in the form of thread slightly improved trail following and mediated trail disruption from high concentrations upwind. Our results indicate that ants are able to use physical structures to reduce but not eliminate the effects of trail pheromone disruption.

Optimisation of a honeybee-colony's energetics via social learning based on queuing delays

NASA Astrophysics Data System (ADS)

Thenius, Ronald; Schmickl, Thomas; Crailsheim, Karl

2008-06-01

Natural selection shaped the foraging-related processes of honeybees in such a way that a colony can react to changing environmental conditions optimally. To investigate this complex dynamic social system, we developed a multi-agent model of the nectar flow inside and outside of a honeybee colony. In a honeybee colony, a temporal caste collects nectar in the environment. These foragers bring their harvest into the colony, where they unload their nectar loads to one or more storer bees. Our model predicts that a cohort of foragers, collecting nectar from a single nectar source, is able to detect changes in quality in other food sources they have never visited, via the nectar processing system of the colony. We identified two novel pathways of forager-to-forager communication. Foragers can gain information about changes in the nectar flow in the environment via changes in their mean waiting time for unloadings and the number of experienced multiple unloadings. This way two distinct groups of foragers that forage on different nectar sources and that never communicate directly can share information via a third cohort of worker bees. We show that this noisy and loosely knotted social network allows a colony to perform collective information processing, so that a single forager has all necessary information available to be able to 'tune' its social behaviour, like dancing or dance-following. This way the net nectar gain of the colony is increased.

Foraging behaviour, nutrient intake from pasture and performance of free-range growing pigs in relation to feed CP level in two organic cropping systems.

PubMed

Jakobsen, M; Kongsted, A G; Hermansen, J E

2015-12-01

In organic pig production one of the major challenges is to be able to fulfil amino acid requirements based on organic and locally grown protein feed crops. The pig is an opportunistic omnivore with a unique capacity for foraging above and below the soil surface. It is hypothesized that direct foraging in the range area can pose an important contribution in terms of fulfilling nutrient requirements of growing pigs. Foraging activity, lucerne nutrient intake and pig performance were investigated in 36 growing pigs, foraging on lucerne or grass and fed either a standard organic pelleted feed mixture (HP: high protein) or a grain mixture containing 48% less CP (LP: low protein) compared with the high protein feed mixture, from an average live weight of 58 kg to 90 kg in a complete block design in three replicates. The pigs were fed 80% of energy recommendations and had access to 4 m2 of pasture/pig per day during the 40 days experimental period from September to October 2013. Behavioural observations were carried out 12 times over the entire experimental period. For both crops, LP pigs rooted significantly more compared with HP pigs but the effect of CP level was more pronounced in grass (44% v. 19% of all observations) compared with lucerne (28% v. 16% of all observations). Feed protein level turned out not to have any significant effect on grazing behaviour but pigs foraging on lucerne grazed significantly more than pigs foraging on grass (10% v. 4% of all observations). Daily weight gain and feed conversion ratio were significantly affected by feed protein and forage crop interactions. Compared to HP pigs, LP treated pigs had 33% lower daily weight gain (589 v. 878 g) and 31% poorer feed conversion ratio (3.75 v. 2.59 kg feed/kg weight gain) in grass paddocks, whereas in lucerne paddocks LP pigs only had 18% lower daily weight gain (741 v. 900 g) and a 14% poorer feed conversion ratio (2.95 v. 2.54 kg feed/kg weight gain) compared with HP pigs. LP pigs foraging on lucerne used 169 g less concentrate CP/kg weight gain, compared with HP pigs, indicating the nitrogen efficiency of the system. The results indicate that direct foraging of lucerne may be a valuable strategy in terms of accommodating CP and lysine requirements of organic growing pigs.

Biological mechanisms associated with increased perseveration and hyperactivity in a genetic mouse model of neurodevelopmental disorder.

PubMed

Trent, Simon; Dean, Rachel; Veit, Bonnie; Cassano, Tommaso; Bedse, Gaurav; Ojarikre, Obah A; Humby, Trevor; Davies, William

2013-08-01

Chromosomal deletions at Xp22.3 appear to influence vulnerability to the neurodevelopmental disorders attention deficit hyperactivity disorder (ADHD) and autism. 39,X(Y*)O mice, which lack the murine orthologue of the Xp22.3 ADHD candidate gene STS (encoding steroid sulfatase), exhibit behavioural phenotypes relevant to such disorders (e.g. hyperactivity), elevated hippocampal serotonin (5-HT) levels, and reduced serum levels of dehydroepiandrosterone (DHEA). Here we initially show that 39,X(Y*)O mice are also deficient for the recently-characterised murine orthologue of the Xp22.3 autism candidate gene ASMT (encoding acetylserotonin-O-methyltransferase). Subsequently, to specify potential behavioural correlates of elevated hippocampal 5-HT arising due to the genetic lesion, we compared 39,X(Y*)O MF1 mice to 40,XY MF1 mice on behavioural tasks taxing hippocampal and/or 5-HT function (a 'foraging' task, an object-location task, and the 1-choice serial reaction time task of impulsivity). Although Sts/Asmt deficiency did not influence foraging behaviour, reactivity to familiar objects in novel locations, or 'ability to wait', it did result in markedly increased response rates; these rates correlated with hippocampal 5-HT levels and are likely to index behavioural perseveration, a frequent feature of neurodevelopmental disorders. Additionally, we show that whilst there was no systematic relationship between serum DHEA levels and hippocampal 5-HT levels across 39,X(Y*)O and 40,XY mice, there was a significant inverse linear correlation between serum DHEA levels and activity. Our data suggest that deficiency for genes within Xp22.3 could influence core behavioural features of neurodevelopmental disorders via dissociable effects on hippocampal neurochemistry and steroid hormone levels, and that the mediating neurobiological mechanisms may be investigated in the 39,X(Y*)O model. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulating secondary succession of elk forage values in a managed forest landscape, western Washington

USGS Publications Warehouse

Jenkins, Kurt J.; Starkey, Edward E.

1996-01-01

Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.

Emergence of Leadership in a Group of Autonomous Robots

PubMed Central

Pugliese, Francesco; Acerbi, Alberto; Marocco, Davide

2015-01-01

In this paper we examine the factors contributing to the emergence of leadership in a group, and we explore the relationship between the role of the leader and the behavioural capabilities of other individuals. We use a simulation technique where a group of foraging robots must coordinate to choose between two identical food zones in order to forage collectively. Behavioural and quantitative analysis indicate that a form of leadership emerges, and that groups with a leader are more effective than groups without. Moreover, we show that the most skilled individuals in a group tend to be the ones that assume a leadership role, supporting biological findings. Further analysis reveals the emergence of different “styles” of leadership (active and passive). PMID:26340449

Variability in energy density of forage fishes from the Bay of Biscay (north-east Atlantic Ocean): reliability of functional grouping based on prey quality.

PubMed

Spitz, J; Jouma'a, J

2013-06-01

Energy densities of 670 fishes belonging to nine species were measured to evaluate intraspecific variability. Functional groups based on energy density appeared to be sufficiently robust to individual variability to provide a classification of forage fish quality applicable in a variety of ecological fields including ecosystem modelling. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae.

PubMed

Sivinski, John; Aluja, Martin

2012-07-20

Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research.

Contrafreeloading in grizzly bears: implications for captive foraging enrichment.

PubMed

McGowan, Ragen T S; Robbins, Charles T; Alldredge, J Richard; Newberry, Ruth C

2010-01-01

Although traditional feeding regimens for captive animals were focused on meeting physiological needs to assure good health, more recently emphasis has also been placed on non-nutritive aspects of feeding. The provision of foraging materials to diversify feeding behavior is a common practice in zoos but selective consumption of foraging enrichment items over more balanced "chow" diets could lead to nutrient imbalance. One alternative is to provide balanced diets in a contrafreeloading paradigm. Contrafreeloading occurs when animals choose resources that require effort to exploit when identical resources are freely available. To investigate contrafreeloading and its potential as a theoretical foundation for foraging enrichment, we conducted two experiments with captive grizzly bears (Ursus arctos horribilis). In Experiment 1, bears were presented with five foraging choices simultaneously: apples, apples in ice, salmon, salmon in ice, and plain ice under two levels of food restriction. Two measures of contrafreeloading were considered: weight of earned food consumed and time spent working for earned food. More free than earned food was eaten, with only two bears consuming food extracted from ice, but all bears spent more time manipulating ice containing salmon or apples than plain ice regardless of level of food restriction. In Experiment 2, food-restricted bears were presented with three foraging choices simultaneously: apples, apples inside a box, and an empty box. Although they ate more free than earned food, five bears consumed food from boxes and all spent more time manipulating boxes containing apples than empty boxes. Our findings support the provision of contrafreeloading opportunities as a foraging enrichment strategy for captive wildlife. (c) 2009 Wiley-Liss, Inc.

Fearful Foragers: Honey Bees Tune Colony and Individual Foraging to Multi-Predator Presence and Food Quality

PubMed Central

Tan, Ken; Hu, Zongwen; Chen, Weiwen; Wang, Zhengwei; Wang, Yuchong; Nieh, James C.

2013-01-01

Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller) and V. tropica (bigger) preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive) as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w), colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55–79% and residence times by 17–33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose), colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger), colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees. PMID:24098734

Antennal proteome comparison of sexually mature drone and forager honeybees.

PubMed

Feng, Mao; Song, Feifei; Aleku, Dereje Woltedji; Han, Bin; Fang, Yu; Li, Jianke

2011-07-01

Honeybees have evolved an intricate system of chemical communication to regulate their complex social interactions. Specific proteins involved in odorant detection most likely supported this chemical communication. Odorant reception takes place mainly in the antennae within hairlike structures called olfactory sensilla. Antennal proteomes of sexually mature drone and forager worker bees (an age group of bees assigned to perform field tasks) were compared using two-dimensional electrophoresis, mass spectrometry, quantitative real-time polymerase chain reaction, and bioinformatics. Sixty-one differentially expressed proteins were identified in which 67% were highly upregulated in the drones' antennae whereas only 33% upregulated in the worker bees' antennae. The antennae of the worker bees strongly expressed carbohydrate and energy metabolism and molecular transporters signifying a strong demand for metabolic energy and odorant binding proteins for their foraging activities and other olfactory responses, while proteins related to fatty acid metabolism, antioxidation, and protein folding were strongly upregulated in the drones' antennae as an indication of the importance for the detection and degradation of sex pheromones during queen identification for mating. On the basis of both groups of altered antenna proteins, carbohydrate metabolism and energy production and molecular transporters comprised more than 80% of the functional enrichment analysis and 45% of the constructed biological interaction networks (BIN), respectively. This suggests these two protein families play crucial roles in the antennal olfactory function of sexually mature drone and forager worker bees. Several key node proteins in the BIN were validated at the transcript level. This first global proteomic comparative analysis of antennae reveals sex-biased protein expression in both bees, indicating that odorant response mechanisms are sex-specific because of natural selection for different olfactory functions. To the best of our knowledge, this result further provides extensive insight into the expression of the proteins in the antennae of drone and worker honeybees and adds vital information to the previous findings. It also provides a new angle for future detailed functional analysis of the antennae of the honeybee castes.

40 CFR 180.527 - Flufenacet, N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1, 3, 4-thiadiazol-2-yl...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Parts per million Grass, forage 7.0 Grass, hay 0.4 (d) Indirect or inadvertent residues. Tolerances are..., except rice 0.1 Grass, forage, fodder, and hay, group 17 0.1 [63 FR 26473, May 13, 1998, as amended by 63...

40 CFR 180.527 - Flufenacet, N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1, 3, 4-thiadiazol-2-yl...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Parts per million Grass, forage 7.0 Grass, hay 0.4 (d) Indirect or inadvertent residues. Tolerances are..., except rice 0.1 Grass, forage, fodder, and hay, group 17 0.1 [63 FR 26473, May 13, 1998, as amended by 63...

The Socioecology of Territory Size and a "Work-Around" Hypothesis for the Adoption of Farming

PubMed Central

Freeman, Jacob

2016-01-01

This paper combines theory from ecology and anthropology to investigate variation in the territory sizes of subsistence oriented agricultural societies. The results indicate that population and the dependence of individuals within a society on “wild” foods partly determine the territory sizes of agricultural societies. In contrast, the productivity of an agroecosystem is not an important determinant of territory size. A comparison of the population-territory size scaling dynamics of agricultural societies and human foragers indicates that foragers and farmers face the same constraints on their ability to expand their territory and intensify their use of resources within a territory. However, the higher density of food in an agroecosystem allows farmers, on average, to live at much higher population densities than human foragers. These macroecological patterns are consistent with a “work-around hypothesis” for the adoption of farming. This hypothesis is that as residential groups of foragers increase in size, farming can sometimes better reduce the tension between an individual’s autonomy over resources and the need for social groups to function to provide public goods like defense and information. PMID:27391955

8. The development and evolution of division of labor and foraging specialization in a social insect (Apis mellifera L.).

PubMed

Page, Robert E; Scheiner, Ricarda; Erber, Joachim; Amdam, Gro V

2006-01-01

How does complex social behavior evolve? What are the developmental building blocks of division of labor and specialization, the hallmarks of insect societies? Studies have revealed the developmental origins in the evolution of division of labor and specialization in foraging worker honeybees, the hallmarks of complex insect societies. Selective breeding for a single social trait, the amount of surplus pollen stored in the nest (pollen hoarding) revealed a phenotypic architecture of correlated traits at multiple levels of biological organization in facultatively sterile female worker honeybees. Verification of this phenotypic architecture in "wild-type" bees provided strong support for a "pollen foraging syndrome" that involves increased senso-motor responses, motor activity, associative learning, reproductive status, and rates of behavioral development, as well as foraging behavior. This set of traits guided further research into reproductive regulatory systems that were co-opted by natural selection during the evolution of social behavior. Division of labor, characterized by changes in the tasks performed by bees, as they age, is controlled by hormones linked to ovary development. Foraging specialization on nectar and pollen results also from different reproductive states of bees where nectar foragers engage in pre-reproductive behavior, foraging for nectar for self-maintenance, while pollen foragers perform foraging tasks associated with reproduction and maternal care, collecting protein.

Fidelity and over-wintering of sea turtles

PubMed Central

Broderick, Annette C; Coyne, Michael S; Fuller, Wayne J; Glen, Fiona; Godley, Brendan J

2007-01-01

While fidelity to breeding sites is well demonstrated in marine turtles, emerging knowledge of migratory routes and key foraging sites is of limited conservation value unless levels of fidelity can be established. We tracked green (Chelonia mydas, n=10) and loggerhead (Caretta caretta, n=10) turtles during their post-nesting migration from the island of Cyprus to their foraging grounds. After intervals of 2–5 years, five of these females were recaptured at the nesting beach and tracked for a second migration. All five used highly similar migratory routes to return to the same foraging and over-wintering areas. None of the females visited other foraging habitats over the study period (units lasted on average 305 days; maximum, 1356 days), moving only to deeper waters during the winter months where they demonstrated extremely long resting dives of up to 10.2 h (the longest breath-holding dive recorded for a marine vertebrate). High levels of fidelity and the relatively discrete nature of the home ranges demonstrate that protection of key migratory pathways, foraging and over-wintering sites can serve as an important tool for the future conservation of marine turtles. PMID:17456456

Anylisis of botanical composition and nutrient content on natural pastures in Samosir Island of Samosir Regency

NASA Astrophysics Data System (ADS)

Hanafi, N. D.; Tafsin, M.; Hutasuhut, U.; Lubis, E.

2018-02-01

Samosir regency is one of the areas that have large grazing area. The potential of grazing production in the area plays an important role for the development of livestock, especially on ruminant livestock.The study aims to know the botanical composition and the nutritional content of forage on natural pasture at the Samosir Island. Animal feed assessment method on natural pastures in Samosir regency includes the determination of research location points based on the altitude through the survey method. Location of the study amounted to 15 locations. The result showed that at altitude 905 - 1200 meters above sea level had a botanical composition were 31 species with ratio of grass 80.58 %, legumes 9.14 % and weeds 9.63 % and the most dominant forage is Imperata cylindrica l. The botanical composition at altitude more than 1205 meters above sea level is 15 species with ratio of grass 92.72 %, legumes 2.87 % and weeds 4.39 % and the most dominant forage is Axonopus compressus. The forage which has the highest crude protein is Starkuak 15.13 %. The conclusion that the altitude in pastures give effect on the botanical composition of forages.

Nectar profitability, not empty honey stores, stimulate recruitment and foraging in Melipona scutellaris (Apidae, Meliponini).

PubMed

Schorkopf, Dirk Louis P; de Sá Filho, Geovan Figueirêdo; Maia-Silva, Camila; Schorkopf, Martina; Hrncir, Michael; Barth, Friedrich G

2016-10-01

In stingless bees (Meliponini) like in many other eusocial insect colonies food hoarding plays an important role in colony survival. However, very little is known on how Meliponini, a taxon restricted to tropical and subtropical regions, respond to different store conditions. We studied the impact of honey removal on nectar foraging activity and recruitment behaviour in Melipona scutellaris and compared our results with studies of the honey bee Apis mellifera. As expected, foraging activity increased significantly during abundance of artificial nectar and when increasing its profitability. Foraging activity on colony level could thereby frequently increase by an order of magnitude. Intriguingly, however, poor honey store conditions did not induce increased nectar foraging or recruitment activity. We discuss possible reasons explaining why increasing recruitment and foraging activity are not used by meliponines to compensate for poor food conditions in the nest. Among these are meliponine specific adaptations to climatic and environmental conditions, as well as physiology and brood rearing, such as mass provisioning of the brood.

Foraging ecology of the endangered wood stork recorded in the stable isotope signature of feathers.

PubMed

Romanek, C S; Gaines, K F; Bryan, A L; Brisbin, I L

2000-12-01

Down feathers and regurgitant were collected from nestling wood storks (Mycteria americana) from two inland and two coastal breeding colonies in Georgia. The stable isotopic ratios of carbon ( 13 C/ 12 C) and nitrogen ( 15 N/ 14 N) in these materials were analyzed to gain insights into the natal origins of juvenile storks and the foraging activities of adults. Down feathers differed in δ 13 C between inland and coastal colonies, having average isotopic values that reflected the sources of carbon fixed in biomass at the base of the food web. Feathers from the inland colonies differed between colonies in δ 15 N, while those from the coastal colonies did not. These patterns primarily reflected the foraging activities of parent storks, with individuals capturing differing percentages of prey of distinct trophic status at each colony. Collectively, the carbon and nitrogen isotopic signatures of feather keratin were used to distinguish nestlings from each colony, except for instances where storks from different colonies foraged in common wetlands. The stable isotopic composition of food items in regurgitant was used to reconstruct the trophic structure of the ecosystems in which wood storks foraged. Predicted foraging activities based on the isotopic composition of keratin were generally consistent with the percentage of prey types (freshwater vs. saltwater and lower trophic level vs. upper trophic level consumer) observed in regurgitant, except for the coastal colony at St. Simons Island, where the δ 13 C of feathers strongly suggested that freshwater prey were a significant component of the diet. This inconsistency was resolved by aerial tracking of adults during foraging excursions using a fixed-wing aircraft. Observed foraging activities supported interpretations based on the stable isotope content of feathers, suggesting that the latter provided a better record of overall foraging activity than regurgitant analysis alone. Observed foraging patterns were compared to the predictions of a statistical model that determined habitat utilization based on habitat availability using a geographic information system (GIS) database. Observed foraging activities and those predicted from feathers both suggested that some adult storks preferred to feed their young freshwater prey, even when saltwater resources were more accessible in the local environment. This conclusion supports the contention that wood stork populations are sensitive to changes in the distribution of freshwater habitats along the southeastern coastal plain of the United States.

The Physiological Suppressing Factors of Dry Forage Intake and the Cause of Water Intake Following Dry Forage Feeding in Goats — A Review

PubMed Central

Sunagawa, Katsunori; Nagamine, Itsuki

2016-01-01

The goats raised in the barn are usually fed on fresh grass. As dry forage can be stored for long periods in large amounts, dry forage feeding makes it possible to feed large numbers of goats in barns. This review explains the physiological factors involved in suppressing dry forage intake and the cause of drinking following dry forage feeding. Ruminants consume an enormous amount of dry forage in a short time. Eating rates of dry forage rapidly decreased in the first 40 min of feeding and subsequently declined gradually to low states in the remaining time of the feeding period. Saliva in large-type goats is secreted in large volume during the first hour after the commencement of dry forage feeding. It was elucidated that the marked suppression of dry forage intake during the first hour was caused by a feeding-induced hypovolemia and the loss of NaHCO3 due to excessive salivation during the initial stages of dry forage feeding. On the other hand, it was indicated that the marked decrease in feed intake observed in the second hour of the 2 h feeding period was related to ruminal distension caused by the feed consumed and the copious amount of saliva secreted during dry forage feeding. In addition, results indicate that the marked decreases in dry forage intake after 40 min of feeding are caused by increases in plasma osmolality and subsequent thirst sensations produced by dry forage feeding. After 40 min of the 2 h dry forage feeding period, the feed salt content is absorbed into the rumen and plasma osmolality increases. The combined effects of ruminal distension and increased plasma osmolality accounted for 77.6% of the suppression of dry forage intake 40 min after the start of dry forage feeding. The results indicate that ruminal distension and increased plasma osmolality are the main physiological factors in suppression of dry forage intake in large-type goats. There was very little drinking behavior observed during the first hour of the 2 h feeding period most water consumption occurring in the second hour. The cause of this thirst sensation during the second hour of dry forage feeding period was not hypovolemia brought about by excessive salivation, but rather increases in plasma osmolality due to the ruminal absorption of salt from the consumed feed. This suggests the water intake following dry forage feeding is determined by the level of salt content in the feed. PMID:26732440

Forage choice in pasturelands: influence on cattle foraging behavior and production

USDA-ARS?s Scientific Manuscript database

We determined if trinary combinations of plants led to complementary relationships that influenced animal behavior and performance over combinations of lower diversity (monocultures). Grazing bouts, behavioral levels of activity, blood urea nitrogen, chemical composition of feces, body weight, and h...

Pteridine levels and head weights are correlated with age and colony task in the honey bee, Apis mellifera

PubMed Central

Rinkevich, Frank D.; Margotta, Joseph W.; Pittman, Jean M.; Ottea, James A.

2016-01-01

Background. The age of an insect strongly influences many aspects of behavior and reproduction. The interaction of age and behavior is epitomized in the temporal polyethism of honey bees in which young adult bees perform nurse and maintenance duties within the colony, while older bees forage for nectar and pollen. Task transition is dynamic and driven by colony needs. However, an abundance of precocious foragers or overage nurses may have detrimental effects on the colony. Additionally, honey bee age affects insecticide sensitivity. Therefore, determining the age of a set of individual honey bees would be an important measurement of colony health. Pteridines are purine-based pigment molecules found in many insect body parts. Pteridine levels correlate well with age, and wild caught insects may be accurately aged by measuring pteridine levels. The relationship between pteridines and age varies with a number of internal and external factors among many species. Thus far, no studies have investigated the relationship of pteridines with age in honey bees. Methods. We established single-cohort colonies to obtain age-matched nurse and forager bees. Bees of known ages were also sampled from colonies with normal demographics. Nurses and foragers were collected every 3–5 days for up to 42 days. Heads were removed and weighed before pteridines were purified and analyzed using previously established fluorometric methods. Results. Our analysis showed that pteridine levels significantly increased with age in a linear manner in both single cohort colonies and colonies with normal demography. Pteridine levels were higher in foragers than nurses of the same age in bees from single cohort colonies. Head weight significantly increased with age until approximately 28-days of age and then declined for both nurse and forager bees in single cohort colonies. A similar pattern of head weight in bees from colonies with normal demography was observed but head weight was highest in 8-day old nurse bees and there was no relationship of head weight with age of foragers. Discussion. Although the relationship between pteridine levels and age was significant, variation in the data yielded a +4-day range in age estimation. This allows an unambiguous method to determine whether a bee may be a young nurse or old forager in colonies with altered demographics as in the case of single cohort colonies. Pteridine levels in bees do not correlate with age as well as in other insects. However, most studies used insects reared under tightly controlled laboratory conditions, while we used free-living bees. The dynamics of head weight change with age is likely to be due to growth and atrophy of the hypopharyngeal glands. Taken together, these methods represent a useful tool for assessing the age of an insect. Future studies utilizing these methods will provide a more holistic view of colony health. PMID:27413635

Foragers of sympatric Asian honey bee species intercept competitor signals by avoiding benzyl acetate from Apis cerana alarm pheromone.

PubMed

Wen, Ping; Cheng, Yanan; Qu, Yufeng; Zhang, Hongxia; Li, Jianjun; Bell, Heather; Tan, Ken; Nieh, James

2017-07-27

While foraging, animals can form inter- and intraspecific social signalling networks to avoid similar predators. We report here that foragers of different native Asian honey bee species can detect and use a specialized alarm pheromone component, benzyl acetate (BA), to avoid danger. We analysed the volatile alarm pheromone produced by attacked workers of the most abundant native Asian honey bee, Apis cerana and tested the responses of other bee species to these alarm signals. As compared to nest guards, A. cerana foragers produced 3.38 fold higher levels of BA. In foragers, BA and (E)-dec-2-en-1-yl acetate (DA) generated the strongest antennal electrophysiological responses. BA was also the only compound that alerted flying foragers and inhibited A. cerana foraging. BA thereby decreased A. cerana foraging for risky sites. Interestingly, although BA occurs only in trace amounts and is nearly absent in sympatric honeybee species (respectively only 0.07% and 0.44% as much in A. dorsata and A. florea), these floral generalists detected and avoided BA as strongly as they did to their own alarm pheromone on natural inflorescences. These results demonstrate that competing pollinators can take advantage of alarm signal information provided by other species.

Imidacloprid slows the development of preference for rewarding food sources in bumblebees (Bombus impatiens).

PubMed

Phelps, Jordan D; Strang, Caroline G; Gbylik-Sikorska, Malgorzata; Sniegocki, Tomasz; Posyniak, Andrzej; Sherry, David F

2018-03-01

Bee pollination is economically and ecologically vital and recent declines in bee populations are therefore a concern. One possible cause of bee declines is pesticide use. Bumblebees exposed to imidacloprid, a neonicotinoid pesticide, have been shown to be less efficient foragers and collect less pollen on foraging trips than unexposed bees. We investigated whether bumblebees (Bombus impatiens) chronically exposed to imidacloprid at field-realistic levels of 2.6 and 10 ppb showed learning deficits that could affect foraging. Bumblebees were tested for their ability to associate flower colour with reward value in a simulated foraging environment. Bumblebees completed 10 foraging trips in which they collected sucrose solution from artificial flowers that varied in sucrose concentration. The reward quality of each artificial flower was predicted by corolla colour. Unexposed bumblebees acquired a preference for feeding on the most rewarding flower colour on the second foraging trip, while bumblebees exposed at 2.6 and 10 ppb did not until their third and fifth trip, respectively. The delay in preference acquisition in exposed bumblebees may be due to reduced flower sampling and shorter foraging trips. These results show that bumblebees exposed to imidacloprid are slow to learn the reward value of flowers and this may explain previously observed foraging inefficiencies associated with pesticide exposure.

Bat guilds, a concept to classify the highly diverse foraging and echolocation behaviors of microchiropteran bats

PubMed Central

Denzinger, Annette; Schnitzler, Hans-Ulrich

2013-01-01

Throughout evolution the foraging and echolocation behaviors as well as the motor systems of bats have been adapted to the tasks they have to perform while searching and acquiring food. When bats exploit the same class of environmental resources in a similar way, they perform comparable tasks and thus share similar adaptations independent of their phylogeny. Species with similar adaptations are assigned to guilds or functional groups. Habitat type and foraging mode mainly determine the foraging tasks and thus the adaptations of bats. Therefore, we use habitat type and foraging mode to define seven guilds. The habitat types open, edge and narrow space are defined according to the bats' echolocation behavior in relation to the distance between bat and background or food item and background. Bats foraging in the aerial, trawling, flutter detecting, or active gleaning mode use only echolocation to acquire their food. When foraging in the passive gleaning mode bats do not use echolocation but rely on sensory cues from the food item to find it. Bat communities often comprise large numbers of species with a high diversity in foraging areas, foraging modes, and diets. The assignment of species living under similar constraints into guilds identifies patterns of community structure and helps to understand the factors that underlie the organization of highly diverse bat communities. Bat species from different guilds do not compete for food as they differ in their foraging behavior and in the environmental resources they use. However, sympatric living species belonging to the same guild often exploit the same class of resources. To avoid competition they should differ in their niche dimensions. The fine grain structure of bat communities below the rather coarse classification into guilds is determined by mechanisms that result in niche partitioning. PMID:23840190

Hooded seal Cystophora cristata foraging areas in the Northeast Atlantic Ocean—Investigated using three complementary methods

PubMed Central

Lydersen, Christian; Biuw, Martin; Haug, Tore; Fedak, Mike A.; Kovacs, Kit M.

2017-01-01

Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs) to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles). Three different methods were used in combination to achieve maximum insight regarding key foraging areas for hooded seals in this region, which have decline by 85% in recent decades: 1) first passage time (FPT); 2) vertical transit rate and; 3) change in dive drift rate. Generalized additive mixed models (GAMM) were applied to each method to determine whether specific habitat characteristics were associated with foraging. Separate models were run for the post-molting and the post-breeding seasons; sex and age classes were included in the GAMMs. All three methods highlighted a few common geographic areas as being important foraging zones; however, there were also some different areas identified by the different methods, which highlights the importance of using multiple indexes when analyzing tracking and diving data to study foraging behavior. Foraging occurred most commonly in relatively shallow areas with high Sea Surface Temperatures (SST), corresponding to continental shelf areas with Atlantic Water masses. All age and sex classes overlapped spatially to some extent, but the different age and sex groups showed differences in the bathymetry of their foraging areas as well as in their vertical use of the water column. When foraging, pups dove in the upper part of the water column in relatively deep areas. Adult females foraged relatively shallowly in deep water areas too, though in shallower areas than pups. Adult males foraged close to the bottom in shallower areas. PMID:29211797

Effects of habitat composition and landscape structure on worker foraging distances of five bumble bee species.

PubMed

Redhead, John W; Dreier, Stephanie; Bourke, Andrew F G; Heard, Matthew S; Jordan, William C; Sumner, Seirian; Wang, Jinliang; Carvell, Claire

2016-04-01

Bumble bees (Bombus spp.) are important pollinators of both crops and wildflowers. Their contribution to this essential ecosystem service has been threatened over recent decades by changes in land use, which have led to declines in their populations. In order to design effective conservation measures, it is important to understand the effects of variation in landscape composition and structure on the foraging activities of worker bumble bees. This is because the viability of individual colonies is likely to be affected by the trade-off between the energetic costs of foraging over greater distances and the potential gains from access to additional resources. We used field surveys, molecular genetics, and fine resolution remote sensing to estimate the locations of wild bumble bee nests and to infer foraging distances across a 20-km² agricultural landscape in southern England, UK. We investigated five species, including the rare B. ruderatus and ecologically similar but widespread B. hortorum. We compared worker foraging distances between species and examined how variation in landscape composition and structure affected foraging distances at the colony level. Mean worker foraging distances differed significantly between species. Bombus terrestris, B. lapidarius, and B. ruderatus exhibited significantly greater mean foraging distances (551, 536, and 501 m, respectively) than B. hortorum and B. pascuorum (336 and 272 m, respectively). There was wide variation in worker foraging distances between colonies of the same species, which was in turn strongly influenced by the amount and spatial configuration of available foraging habitats. Shorter foraging distances were found for colonies where the local landscape had high coverage and low fragmentation of semi-natural vegetation, including managed agri-environmental field margins. The strength of relationships between different landscape variables and foraging distance varied between species, for example the strongest relationship for B. ruderatus being with floral cover of preferred forage plants. Our findings suggest that management of landscape composition and configuration has the potential to reduce foraging distances across a range of bumble bee species. There is thus potential for improvements in the design and implementation of landscape management options, such as agri-environment schemes, aimed at providing foraging habitat for bumble bees and enhancing crop pollination services.

Possible use of heterospecific food-associated calls of macaques by sika deer for foraging efficiency.

PubMed

Koda, Hiroki

2012-09-01

Heterospecific communication signals sometimes convey relevant information for animal survival. For example, animals use or eavesdrop on heterospecific alarm calls concerning common predators. Indeed, most observations have been reported regarding anti-predator strategies. Use of heterospecific signals has rarely been observed as part of a foraging strategy. Here, I report empirical evidence, collected using playback experiments, showing that Japanese sika deer, Cevus nippon, use heterospecific food calls of Japanese macaques, Macaca fuscata yakui, for foraging efficiency. The deer and macaques both inhabit the wild forest of Yakushima Island with high population densities and share many food items. Anecdotal observations suggest that deer often wait to browse fruit falls under the tree where a macaque group is foraging. Furthermore, macaques frequently produce food calls during their foraging. If deer effectively obtain fruit from the leftovers of macaques, browsing fruit fall would provide a potential benefit to the deer, and, further, deer are likely to associate macaque food calls with feeding activity. The results showed that playback of macaque food calls under trees gathered significantly more deer than silence control periods. These results suggest that deer can associate macaque food calls with foraging activities and use heterospecific calls for foraging efficiency. Copyright © 2012 Elsevier B.V. All rights reserved.

Multiple-stage decisions in a marine central-place forager

PubMed Central

Friedlaender, Ari S.; Johnston, David W.; Tyson, Reny B.; Kaltenberg, Amanda; Goldbogen, Jeremy A.; Stimpert, Alison K.; Curtice, Corrie; Hazen, Elliott L.; Halpin, Patrick N.; Read, Andrew J.; Nowacek, Douglas P.

2016-01-01

Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator–prey interactions and underscores the need to simultaneously measure prey distribution in marine central place forager studies. PMID:27293784

Stopover ecology of Semipalmated Sandpipers (Calidris pusilla) at coastal deltas of the Beaufort Sea, Alaska

NASA Astrophysics Data System (ADS)

Churchwell, Roy T.

Avian migration is one of the wonders of the natural world. Stored fats are the main source of nutrients and fuel for avian migration and it is assumed the fat deposition at stopover sites is a critical component of a successful migration. Stopover sites are crucial in the successful migration of many birds, but particularly for arctic-breeding shorebirds that migrate long distances from breeding to wintering grounds. Despite the importance of stopover sites, it is often difficult to determine the importance of these sites to migrating shorebirds. I investigated three aspects of stopover ecology of Semipalmated Sandpipers (Calidris pusilla) foraging at coastal deltas on the Beaufort Sea coast, Alaska. First, I quantified the spatial and temporal distribution and abundance of the benthic macroinvertebrate community living within the mudflats. I found that there were two ecological groups of macroinvertebrates using river deltas, one originated in terrestrial freshwater habitats and most importantly could withstand freezing in delta sediments over the winter, and the other originated from the marine environment, could not withstand freezing and had to migrate to intertidal habitats each summer from deeper water areas that did not freeze over the winter. Stable isotope analysis allowed me to describe the origin of carbon consumed by invertebrates in intertidal habitats. I predicted freshwater invertebrates would consume terrestrial carbon, and marine invertebrates would consume marine carbon, but I found that both groups utilized the same carbon, which was a mixture of terrestrial and marine sources. My second research question determined the importance of delta foraging habitat for fall migrating Semipalmated Sandpipers. I mapped the temporal distribution and abundance of birds and quantified this relationship to invertebrate distribution and abundance. I researched fattening rates of shorebirds by measuring triglycerides in the blood of shorebirds I captured. I hypothesized that triglyceride levels would be correlated with invertebrate abundance and related to habitat quality; however, I found no relationship. Next, I determined shorebird dependence on marine invertebrates using the stable isotope signature of invertebrates and shorebird plasma. I found that shorebird abundance was associated with invertebrate abundance, and that shorebirds did feed almost exclusively on invertebrates from the mudflats later in the season. I did not find a significant difference in habitat quality among the deltas, although more birds were counted at the Jago Delta than at the other two deltas. Finally, I researched the question of how change in water levels due to lunar tides and storm surge events impacted the availability of foraging habitat. I assessed the phenology of Semipalmated Sandpiper migration and how this related to the availability of forage based on abundance, distribution, and accessibility of macroinvertebrates. There was a significant decline in the calories available for forage when there was a lunar tide and when there was a storm surge event. The most foraging habitat was available late in the migration period, while the peak in Semipalmated Sandpiper migration was early in the period. Late in the season there is also a greater chance of a storm surge event occurring due to the lack of sea ice during that period. In summary, I found Beaufort Sea deltas were more diverse than I expected both in macroinvertebrate community and in how shorebirds use the available foraging habitat. After completing this research I feel this habitat is critical to Semipalmated Sandpiper migration; however, there is a real risk of extensive change to these deltas due to future warming with negative consequences for shorebirds.

Chemical discrimination by tongue-flicking in lizards: A review with hypotheses on its origin and its ecological and phylogenetic relationships.

PubMed

Cooper, W E

1994-02-01

Tongue-flicking is a synapomorphy of squamate reptiles functioning to sample chemicals for vomerolfactory analysis, which became possible in primitive squamates when ducts opened from the vomeronasal organs to the roof of the mouth. Extant iguanian lizards in families that do not use the tongue to sample chemical prey cues prior to attack partially protrude it in two feeding contexts: during capture by lingual prehension and after oral contact with prey. These lizards do not exhibit strike-induced chemosensory searching. Lingual prey prehension is present in iguanian lizards and inSphenodon, the sister taxon of Squamata. During attempts to capture prey, the tongues of primitive squamates inevitably made incidental contact with environmental substrates bearing chemicals deposited by prey, conspecifics, and predators. Such contact presumably induced selection for tongue-flicking and ability to identify biologically important chemicals. Most iguanian lizards are ambush foragers that use immobility as a major antipredatory defense. Because tongue-flicking at an ambush post would not allow chemical search beyond the vicinity of the head and would render them easier for predators and prey to detect, typical iguanians tongue-flick neither while foraging nor to identify predators. They do detect pheromones by tongue-flicking. Scleroglossan lizards are typically active foragers that rely on speed to escape. Being freer to move the tongue, they have evolved lingual sampling allowing detection of chemical cues of conspecifics, predators, and prey, as well as strike-induced chemosensory searching, some can follow pheromone trails by tongue-flicking. Some families have lingual morphology and behavior specialized for chemosensory sampling. In varanids and snakes, the taxa showing the greatest lingual specialization, additional prey-related chemosensory behaviors have evolved. In iguanian and scleroglossan families that have secondarily adopted the foraging mode typical of the other taxon, prey chemical discrimination involving tongue-flicking and strike-induced chemosensory searching are typical for the foraging mode rather than the taxon. Because foraging mode and state of prey chemical discrimination are stable within squamate families and to a large extent in higher taxa, both features have been retained from the ancestral condition in most families. However, in three cases in which foraging mode has changed from its ancestral state, the state of prey chemical discrimination has also changed, indicating that prey chemical discrimination is adaptively adjusted to foraging mode. Indeed, acquisition of lingually mediated prey chemical discrimination may have made feasible the evolution of active foraging, which in turn appears to have profoundly influenced the further evolution of squamate chemosensory structures and behavior, placing a selective premium on features enhancing the tongue's efficiency as a chemical sampling device. The advent of tongue-flicking to sample prey chemicals and thus detect hidden prey may have allowed generalist (cruise) or ambush foragers, if early squamates were such, to become specialists in active foraging. Alternatively, if the common ancestors of squamates were active foragers, the adoption of ambush foraging would have selected against participation of the tongue in locating prey. Acting jointly, tongue-flicking and active foraging have had momentous consequences for squamate diversification. Specialization for active foraging would appear to have had ramifying effects on antipredatory defenses, body form, territoriality, mating systems, and reproductive physiology.

Sexual division of labor: energetic and evolutionary scenarios.

PubMed

Panter-Brick, Catherine

2002-01-01

This article examines comparative energetic data on hunter-gatherers in the context of evolutionary scenarios of the sexual division of labor, with respect to both specific task allocation and overall levels of daily physical activity. The division of labor between men and women, well marked in contemporary foraging societies, was once posited as the "true watershed" for the evolution of the genus Homo. Some research on brain-wiring even links sex differences in cognitive and spatial abilities to sex-specific foraging activities. Most recent evolutionary arguments posit that men focus on hunting and women on gathering activities to realize potentially conflicting mating and parenting goals. A range of cooperative strategies (male/female and female/female) for child provisioning is also under investigation. Attention to energetic and reproductive trade-offs has usefully challenged the proposition that women are excluded from big-game hunting due to constraints of foraging ecology and reproduction. Simplistic assumptions about gender roles are thus increasingly questioned in anthropology, as well as in archaeology. Current models in behavioral ecology explore ways in which foraging practices vary with ecological circumstances, aiming to derive testable hypotheses from fine-grained data on the behavior of contemporary hunter-gatherers. Data on overall physical activity levels (PAL) can also serve to evaluate relative male/female workloads in modern groups, reconstruct hominid energy requirements and activity profiles, and examine changes with subsistence intensification. Male/female PAL ratios show that a task-specific division of labor does not readily extrapolate to 24-hour energy expenditure and that male/female differences in workloads were not necessarily reduced with the transition to agriculture. With respect to gender roles and PAL, a shift away from facile stereotypes of human behavior is evident. The challenge is to incorporate a range of behavioral responses to ecological circumstances in reconstructions of our evolutionary past. Copyright 2002 Wiley-Liss, Inc.

Sward structure and nutritive value of Alexandergrass fertilized with nitrogen.

PubMed

Salvador, Paulo R; Pötter, Luciana; Rocha, Marta G; Hundertmarck, Anelise P; Sichonany, Maria José O; Amaral Neto, Luiz G; Negrini, Mateus; Moterle, Paulo H

2016-03-01

This experiment evaluated forage production, sward structure, stocking rate, weight gain per area and nutritive value of forage as grazed by beef heifers on Alexandergrass (Urochloa plantaginea (Link) Hitch) pasture fertilized with nitrogen (N): 0; 100; 200 or 300 kg of N/ha. The experiment was a completely randomized design following a repeated measurement arrangement. The experimental animals were Angus heifers with initial age and weight of 15 months and 241.5±5 kg, respectively. The grazing method was continuous, with put-and-take stocking. N utilization, regardless of the level, increase by 25% the daily forage accumulation rate and the weight gain per area by 23%. The level of 97.2 kg N/ha leads to a higher leaf blade mass and increases by 20% the leaf:stem ratio. Alterations in sward structure changes the nutritive value of forage as grazed. The utilization of 112.7 kg of N/ha allows the highest stocking rate (2049.8 kg of BW/ha), equivalent to 7.5 heifers per hectare.

Social-bond strength influences vocally mediated recruitment to mobbing

PubMed Central

2016-01-01

Strong social bonds form between individuals in many group-living species, and these relationships can have important fitness benefits. When responding to vocalizations produced by groupmates, receivers are expected to adjust their behaviour depending on the nature of the bond they share with the signaller. Here we investigate whether the strength of the signaller–receiver social bond affects response to calls that attract others to help mob a predator. Using field-based playback experiments on a habituated population of wild dwarf mongooses (Helogale parvula), we first demonstrate that a particular vocalization given on detecting predatory snakes does act as a recruitment call; receivers were more likely to look, approach and engage in mobbing behaviour than in response to control close calls. We then show that individuals respond more strongly to these recruitment calls if they are from groupmates with whom they are more strongly bonded (those with whom they preferentially groom and forage). Our study, therefore, provides novel evidence about the anti-predator benefits of close bonds within social groups. PMID:27903776

Wood bison population recovery and forage availability in northwestern Canada.

PubMed

Strong, Wayne L; Gates, C Cormack

2009-01-01

Forage availability was assessed to determine sustainable stocking rates for eight broadly defined vegetation types (Treed Uplands, Treed Lowlands, Mixed Tall Shrub/Sedge, Closed-canopied Willow, and Open-canopied Willow, Meadow, Wetland Grass, Wetland Sedge) for use by wood bison (Bison bison athabascae), a threatened subspecies, in the Canadian boreal forest of northern Alberta. Clip plots (n=108) were used to sample peak availability of herbs and current annual growth of Salix spp. in late summer. Graminoid wetlands dominated by Carex atherodes, Carex aquatilis, Carex utriculata, Scolochloa festucacea, or Calamagrostis stricta produced 1975-4575 kg ha(-1) of fair to good quality forage, whereas treed stands produced < 250 kg ha(-1) of forb-dominated forage (>85% content), which was below a published 25% foraging efficiency threshold of 263 kg ha(-1) for bison. Upland forests that dominate the region produced < or = 1 animal unit day (AUD) of forage per hectare in summer. Most forest understory plants were of poor forage value, suggesting the potential sustainable stocking rate of such areas was actually < or = 0.3 AUD ha(-1), with even lower rates during winter due to snow cover. Herbaceous wetlands contained approximately 78 AUD ha(-1) of forage, but were considered largely unavailable in summer because of flooding and soft organic soils that make access difficult. Conversion of prime foraging habitat to agricultural land, forest expansion due to fire control, and a warmer and wetter climatic regime after the mid-1900s likely contributed to a regional reduction in carrying capacity. It is hypothesized that substantial recovery of the wood bison population toward historical levels will be constrained in northern Alberta by the availability of summer forage, and the limited extent of graminoid wetlands that provide winter foraging habitat.

Linking Foraging Decisions to Residential Yard Bird Composition

PubMed Central

Lerman, Susannah B.; Warren, Paige S.; Gan, Hilary; Shochat, Eyal

2012-01-01

Urban bird communities have higher densities but lower diversity compared with wildlands. However, recent studies show that residential urban yards with native plantings have higher native bird diversity compared with yards with exotic vegetation. Here we tested whether landscape designs also affect bird foraging behavior. We estimated foraging decisions by measuring the giving-up densities (GUD; amount of food resources remaining when the final forager quits foraging on an artificial food patch, i.e seed trays) in residential yards in Phoenix, AZ, USA. We assessed how two yard designs (mesic: lush, exotic vegetation; xeric: drought-tolerant and native vegetation) differed in foraging costs. Further, we developed a statistical model to calculate GUDs for every species visiting the seed tray. Birds foraging in mesic yards depleted seed trays to a lower level (i.e. had lower GUDs) compared to birds foraging in xeric yards. After accounting for bird densities, the lower GUDs in mesic yards appeared largely driven by invasive and synanthropic species. Furthermore, behavioral responses of individual species were affected by yard design. Species visiting trays in both yard designs had lower GUDs in mesic yards. Differences in resource abundance (i.e., alternative resources more abundant and of higher quality in xeric yards) contributed to our results, while predation costs associated with foraging did not. By enhancing the GUD, a common method for assessing the costs associated with foraging, our statistical model provided insights into how individual species and bird densities influenced the GUD. These differences we found in foraging behavior were indicative of differences in habitat quality, and thus our study lends additional support for native landscapes to help reverse the loss of urban bird diversity. PMID:22927974

The forager oral tradition and the evolution of prolonged juvenility.

PubMed

Scalise Sugiyama, Michelle

2011-01-01

The foraging niche is characterized by the exploitation of nutrient-rich resources using complex extraction techniques that take a long time to acquire. This costly period of development is supported by intensive parental investment. Although human life history theory tends to characterize this investment in terms of food and care, ethnographic research on foraging skill transmission suggests that the flow of resources from old-to-young also includes knowledge. Given the adaptive value of information, parents may have been under selection pressure to invest knowledge - e.g., warnings, advice - in children: proactive provisioning of reliable information would have increased offspring survival rates and, hence, parental fitness. One way that foragers acquire subsistence knowledge is through symbolic communication, including narrative. Tellingly, oral traditions are characterized by an old-to-young transmission pattern, which suggests that, in forager groups, storytelling might be an important means by which adults transfer knowledge to juveniles. In particular, by providing juveniles with vicarious experience, storytelling may expand episodic memory, which is believed to be integral to the generation of possible future scenarios (i.e., planning). In support of this hypothesis, this essay reviews evidence that: mastery of foraging knowledge and skill sets takes a long time to acquire; foraging knowledge is transmitted from parent to child; the human mind contains adaptations specific to social learning; full assembly of learning mechanisms is not complete in early childhood; and forager oral traditions contain a wide range of information integral to occupation of the foraging niche. It concludes with suggestions for tests of the proposed hypothesis.

The Forager Oral Tradition and the Evolution of Prolonged Juvenility

PubMed Central

Scalise Sugiyama, Michelle

2011-01-01

The foraging niche is characterized by the exploitation of nutrient-rich resources using complex extraction techniques that take a long time to acquire. This costly period of development is supported by intensive parental investment. Although human life history theory tends to characterize this investment in terms of food and care, ethnographic research on foraging skill transmission suggests that the flow of resources from old-to-young also includes knowledge. Given the adaptive value of information, parents may have been under selection pressure to invest knowledge – e.g., warnings, advice – in children: proactive provisioning of reliable information would have increased offspring survival rates and, hence, parental fitness. One way that foragers acquire subsistence knowledge is through symbolic communication, including narrative. Tellingly, oral traditions are characterized by an old-to-young transmission pattern, which suggests that, in forager groups, storytelling might be an important means by which adults transfer knowledge to juveniles. In particular, by providing juveniles with vicarious experience, storytelling may expand episodic memory, which is believed to be integral to the generation of possible future scenarios (i.e., planning). In support of this hypothesis, this essay reviews evidence that: mastery of foraging knowledge and skill sets takes a long time to acquire; foraging knowledge is transmitted from parent to child; the human mind contains adaptations specific to social learning; full assembly of learning mechanisms is not complete in early childhood; and forager oral traditions contain a wide range of information integral to occupation of the foraging niche. It concludes with suggestions for tests of the proposed hypothesis. PMID:21897825

Tropical tannin-rich fodder intake modifies saliva-binding capacity in growing sheep.

PubMed

Vargas-Magaña, J J; Aguilar-Caballero, A J; Torres-Acosta, J F J; Sandoval-Castro, C A; Hoste, H; Capetillo-Leal, C M

2013-12-01

We evaluated the effect of feeding dietary tannins from Lysiloma latisiliquum fresh forage on the saliva tannin-binding capacity of hair sheep lambs without previous exposure to tannin-rich (TR) fodder. Twenty-four hair sheep lambs (13.6±3.04 kg LW) were fed a tannin-free diet at the beginning of the experimental period (from day 10 to 13). On day 14, lambs were distributed into three groups (n=8): control group (CG), fed with the tannin-free diet (from D10 to D112); tannin short-term group (TST), fed the basal diet and 650 g of L. latisiliquum forage (from D14 to D55); tannin long-term group (TLT), fed the basal diet and 650 g of L. latisiliquum forage (from D14 to D112). Saliva samples were collected from the mouth of each lamb in the morning before feeding time on D10 and D14 (baseline period), on D49 and D56 (period 1) and on D97 and D112 (period 2). The tannin binding response of salivary protein (∆% turbidity) was determined with the haze development test (HDT) using either tannic acid or L. latisiliquum forage acetone extract. A turbidity protein index (TPI) was calculated as (∆% turbidity/[salivary protein (mg)]). Differences in HDT and TPI in the different groups were compared by repeated measures ANOVA using Proc Mixed. All groups had similar ∆% turbidity throughout the experiment (P>0.05). At baseline and period 1, the TPI of the different groups was similar (P>0.05). On period 2 the TLT group showed higher TPI compared with CG (P<0.05). Meanwhile, CG and TST showed similar salivary TPI. The saliva of hair sheep lambs consuming TR L. latisiliquum fresh fodder (TLT group) increased their TPI compared with control lambs not exposed to tannins.

Some correlations between the foraging behavior of common nighthawks, Cbordeiles minor (Forester), and the swarming behavior of two species of ants, Atta texana (Buckley) and Iridomyrmex pruinosis (Roger)

Treesearch

Stuart L. Warter; John C. Moser; Murray S. Blum

1962-01-01

At about 5:30 AM, may 24, 1961, four Common Nighthawks, Chordeiles minor, were collected from a group of nearly a dozen feeding at low level along a roadside in Rapides Parish, west of Alexandria, Louisiana. Upon subsequent examination of the distended stomachs of these birds, it was found that approximately 70% of the contents consisted of winged...

Major Quantitative Trait Loci Affecting Honey Bee Foraging Behavior

PubMed Central

Hunt, G. J.; Page-Jr., R. E.; Fondrk, M. K.; Dullum, C. J.

1995-01-01

We identified two genomic regions that affect the amount of pollen stored in honey bee colonies and influence whether foragers will collect pollen or nectar. We selected for the amount of pollen stored in combs of honey bee colonies, a colony-level trait, and then used random amplified polymorphic DNA (RAPD) markers and interval mapping procedures with data from backcross colonies to identify two quantitative trait loci (pln1 and pln2, LOD 3.1 and 2.3, respectively). Quantitative trait loci effects were confirmed in a separate cross by demonstrating the cosegregation of marker alleles with the foraging behavior of individual workers. Both pln1 and pln2 had an effect on the amount of pollen carried by foragers returning to the colony, as inferred by the association between linked RAPD marker alleles, D8-.3f and 301-.55, and the individual pollen load weights of returning foragers. The alleles of the two marker loci were nonrandomly distributed with respect to foraging task. The two loci appeared to have different effects on foraging behavior. Individuals with alternative alleles for the marker linked to pln2 (but not pln1) differed with respect to the nectar sugar concentration of their nectar loads. PMID:8601492

Scrounging by foragers can resolve the paradox of enrichment

PubMed Central

2017-01-01

Theoretical models of predator–prey systems predict that sufficient enrichment of prey can generate large amplitude limit cycles, paradoxically causing a high risk of extinction (the paradox of enrichment). Although real ecological communities contain many gregarious species, whose foraging behaviour should be influenced by socially transmitted information, few theoretical studies have examined the possibility that social foraging might resolve this paradox. I considered a predator population in which individuals play the producer–scrounger foraging game in one-prey-one-predator and two-prey-one-predator systems. I analysed the stability of a coexisting equilibrium point in the one-prey system and that of non-equilibrium dynamics in the two-prey system. The results revealed that social foraging could stabilize both systems, and thereby resolve the paradox of enrichment when scrounging behaviour (i.e. kleptoparasitism) is prevalent in predators. This suggests a previously neglected mechanism underlying a powerful effect of group-living animals on the sustainability of ecological communities. PMID:28405371

Combining LANDSAT MSS, aerial photographs and ground measurements to estimate rangeland productivity

NASA Technical Reports Server (NTRS)

Gialdini, M. J.

1981-01-01

The production of a vegetation map of over 2.2 million acres with detail down to the plant community level, and the production of estimates of rangeland productivity (pounds of usable forage per acre for cattle) for a 500,000 acre subset of area with a design goal for accuracy and precision of + or - 20% at the 80% confidence level, are considered. The data consist of five groups: maps of area, LANDSAT data, digital terrain data, large scale aerial photography, and ground plots. An outline of the data acquisition and data reduction schemes are presented.

Can Foraging Ecology Drive the Evolution of Body Size in a Diving Endotherm?

PubMed Central

Cook, Timothée R.; Lescroël, Amélie; Cherel, Yves; Kato, Akiko; Bost, Charles-André

2013-01-01

Within a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes. PMID:23409169

Can foraging ecology drive the evolution of body size in a diving endotherm?

PubMed

Cook, Timothée R; Lescroël, Amélie; Cherel, Yves; Kato, Akiko; Bost, Charles-André

2013-01-01

Within a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes.

The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae

PubMed Central

Sivinski, John; Aluja, Martin

2012-01-01

Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research. PMID:26466622

Traffic noise reduces foraging efficiency in wild owls

NASA Astrophysics Data System (ADS)

Senzaki, Masayuki; Yamaura, Yuichi; Francis, Clinton D.; Nakamura, Futoshi

2016-08-01

Anthropogenic noise has been increasing globally. Laboratory experiments suggest that noise disrupts foraging behavior across a range of species, but to reveal the full impacts of noise, we must examine the impacts of noise on foraging behavior among species in the wild. Owls are widespread nocturnal top predators and use prey rustling sounds for localizing prey when hunting. We conducted field experiments to examine the effect of traffic noise on owls’ ability to detect prey. Results suggest that foraging efficiency declines with increasing traffic noise levels due to acoustic masking and/or distraction and aversion to traffic noise. Moreover, we estimate that effects of traffic noise on owls’ ability to detect prey reach >120 m from a road, which is larger than the distance estimated from captive studies with bats. Our study provides the first evidence that noise reduces foraging efficiency in wild animals, and highlights the possible pervasive impacts of noise.

Traffic noise reduces foraging efficiency in wild owls.

PubMed

Senzaki, Masayuki; Yamaura, Yuichi; Francis, Clinton D; Nakamura, Futoshi

2016-08-18

Anthropogenic noise has been increasing globally. Laboratory experiments suggest that noise disrupts foraging behavior across a range of species, but to reveal the full impacts of noise, we must examine the impacts of noise on foraging behavior among species in the wild. Owls are widespread nocturnal top predators and use prey rustling sounds for localizing prey when hunting. We conducted field experiments to examine the effect of traffic noise on owls' ability to detect prey. Results suggest that foraging efficiency declines with increasing traffic noise levels due to acoustic masking and/or distraction and aversion to traffic noise. Moreover, we estimate that effects of traffic noise on owls' ability to detect prey reach >120 m from a road, which is larger than the distance estimated from captive studies with bats. Our study provides the first evidence that noise reduces foraging efficiency in wild animals, and highlights the possible pervasive impacts of noise.

Burrowing and foraging activity of marsh crabs under different inundation regimes

EPA Science Inventory

New England salt marshes are susceptible to degradation and habitat loss as a result of increased periods of inundation as sea levels rise. Increased inundation may exacerbate marsh degradation that can result from crab burrowing and foraging. Most studies to date have focused on...

Precision-feeding dairy heifers a high rumen-undegradable protein diet with different proportions of dietary fiber and forage-to-concentrate ratios.

PubMed

Koch, L E; Gomez, N A; Bowyer, A; Lascano, G J

2017-12-01

The addition of dietary fiber can alter nutrient and N utilization in precision-fed dairy heifers and may further benefit from higher inclusion levels of RUP. The objective of this experiment was to determine the effects of feeding a high-RUP diet when dietary fiber content was manipulated within differing forage-to-concentrate ratios (F:C) on nutrient utilization of precision-fed dairy heifers. Six rumen-cannulated Holstein heifers (555.4 ± 31.4 kg BW; 17.4 ± 0.1 mo) were randomly assigned to 2 levels of forage, high forage (HF; 60% forage) or low forage (LF; 45% forage), and to a fiber proportion sequence (low fiber: 100% oat hay and silage [OA], 0% wheat straw [WS]; medium fiber: 83.4% OA, 16.6% WS; and high fiber: 66.7% OA, 33.3% WS) administered according to a split-plot 3 × 3 Latin square design (21-d periods). Similar levels of N intake (1.70 g N/kg BW) and RUP (55% of CP) were provided. Data were analyzed as a split-plot, 3 × 3 Latin square design using a mixed model with fixed effects of period and treatment. A repeated measures model was used with data that had multiple measurements over time. No differences were observed for DM, OM, NDF, or ADF apparent digestibility coefficients (dC) between HF- and LF-fed heifers. Heifers receiving LF diets had greater starch dC compared to HF heifers. Increasing the fiber level through WS addition resulted in a linear reduction of OM dC. There was a linear interaction for DM dC with a concurrent linear interaction in NDF dC. Nitrogen intake, dC, and retention did not differ; however, urine and total N excretion increased linearly with added fiber. Predicted microbial CP flow (MP) linearly decreased with WS inclusion mainly in LF heifers, as indicated by a significant interaction between F:C and WS. Rumen pH linearly increased with WS addition, although no F:C effect was detected. Ruminal ammonia concentration had an opposite linear effect with respect to MP as WS increased. Diets with the higher proportion of fiber benefited the most from a high RUP supply, complementing the substantial reduction in predicted MP caused by the incremental dietary fiber concentration. These results suggest that RUP supplementation is a practical method for reestablishing optimal ruminal N balance in the event of increased dietary fiber through forage inclusion in precision-fed dairy heifer diets.

Evolution of population structure in a highly social top predator, the killer whale.

PubMed

Hoelzel, A Rus; Hey, Jody; Dahlheim, Marilyn E; Nicholson, Colin; Burkanov, Vladimir; Black, Nancy

2007-06-01

Intraspecific resource partitioning and social affiliations both have the potential to structure populations, though it is rarely possible to directly assess the impact of these mechanisms on genetic diversity and population divergence. Here, we address this for killer whales (Orcinus orca), which specialize on prey species and hunting strategy and have long-term social affiliations involving both males and females. We used genetic markers to assess the structure and demographic history of regional populations and test the hypothesis that known foraging specializations and matrifocal sociality contributed significantly to the evolution of population structure. We find genetic structure in sympatry between populations of foraging specialists (ecotypes) and evidence for isolation by distance within an ecotype. Fitting of an isolation with migration model suggested ongoing, low-level migration between regional populations (within and between ecotypes) and small effective sizes for extant local populations. The founding of local populations by matrifocal social groups was indicated by the pattern of fixed mtDNA haplotypes in regional populations. Simulations indicate that this occurred within the last 20,000 years (after the last glacial maximum). Our data indicate a key role for social and foraging behavior in the evolution of genetic structure among conspecific populations of the killer whale.

It's not black or white—on the range of vision and echolocation in echolocating bats

PubMed Central

Boonman, Arjan; Bar-On, Yinon; Cvikel, Noam; Yovel, Yossi

2013-01-01

Around 1000 species of bats in the world use echolocation to navigate, orient, and detect insect prey. Many of these bats emerge from their roost at dusk and start foraging when there is still light available. It is however unclear in what way and to which extent navigation, or even prey detection in these bats is aided by vision. Here we compare the echolocation and visual detection ranges of two such species of bats which rely on different foraging strategies (Rhinopoma microphyllum and Pipistrellus kuhlii). We find that echolocation is better than vision for detecting small insects even in intermediate light levels (1–10 lux), while vision is advantageous for monitoring far-away landscape elements in both species. We thus hypothesize that, bats constantly integrate information acquired by the two sensory modalities. We suggest that during evolution, echolocation was refined to detect increasingly small targets in conjunction with using vision. To do so, the ability to hear ultrasonic sound is a prerequisite which was readily available in small mammals, but absent in many other animal groups. The ability to exploit ultrasound to detect very small targets, such as insects, has opened up a large nocturnal niche to bats and may have spurred diversification in both echolocation and foraging tactics. PMID:24065924

Why Do Kestrels Soar?

PubMed Central

Hernández-Pliego, Jesús; Rodríguez, Carlos; Bustamante, Javier

2015-01-01

Individuals allocate considerable amounts of energy to movement, which ultimately affects their ability to survive and reproduce. Birds fly by flapping their wings, which is dependent on the chemical energy produced by muscle work, or use soaring-gliding flight, in which chemical energy is replaced with energy harvested from moving air masses, such as thermals. Flapping flight requires more energy than soaring-gliding flight, and this difference in the use of energy increases with body mass. However, soaring-gliding results in lower speeds than flapping, especially for small species. Birds therefore face a trade-off between energy and time costs when deciding which flight strategy to use. Raptors are a group of large birds that typically soar. As relatively light weight raptors, falcons can either soar on weak thermals or fly by flapping with low energy costs. In this paper, we study the flight behavior of the insectivorous lesser kestrel (Falco naumanni) during foraging trips and the influence of solar radiation, which we have adopted as a proxy for thermal formation, on kestrel flight variables. We tracked 35 individuals from two colonies using high frequency GPS-dataloggers over four consecutive breeding seasons. Contrary to expectations, kestrels relied heavily on thermal soaring when foraging, especially during periods of high solar radiation. This produced a circadian pattern in the kestrel flight strategy that led to a spatial segregation of foraging areas. Kestrels flapped towards foraging areas close to the colony when thermals were not available. However, as soon as thermals were formed, they soared on them towards foraging areas far from the colony, especially when they were surrounded by poor foraging habitats. This reduced the chick provisioning rate at the colony. Given that lesser kestrels have a preference for feeding on large insects, and considering the average distance they cover to capture them during foraging trips, to commute using flapping flight would result in a negative energy balance for the family group. Our results show that lesser kestrels prioritize saving energy when foraging, suggesting that kestrels are more energy than time-constrained during the breeding season. PMID:26689780

Patch dynamics of a foraging assemblage of bees.

PubMed

Wright, David Hamilton

1985-03-01

The composition and dynamics of foraging assemblages of bees were examined from the standpoint of species-level arrival and departure processes in patches of flowers. Experiments with bees visiting 4 different species of flowers in subalpine meadows in Colorado gave the following results: 1) In enriched patches the rates of departure of bees were reduced, resulting in increases in both the number of bees per species and the average number of species present. 2) The reduction in bee departure rates from enriched patches was due to mechanical factors-increased flower handling time, and to behavioral factors-an increase in the number of flowers visited per inflorescence and in the number of inflorescences visited per patch. Bees foraging in enriched patches could collect nectar 30-45% faster than those foraging in control patches. 3) The quantitative changes in foraging assemblages due to enrichment, in terms of means and variances of species population sizes, fraction of time a species was present in a patch, and in mean and variance of the number of species present, were in reasonable agreement with predictions drawn from queuing theory and studies in island biogeography. 4) Experiments performed with 2 species of flowers with different corolla tube lengths demonstrated that manipulation of resources of differing availability had unequal effects on particular subsets of the larger foraging community. The arrival-departure process of bees on flowers and the immigration-extinction process of species on islands are contrasted, and the value of the stochastic, species-level approach to community composition is briefly discussed.

Species differences in brain gene expression profiles associated with adult behavioral maturation in honey bees.

PubMed

Sen Sarma, Moushumi; Whitfield, Charles W; Robinson, Gene E

2007-06-29

Honey bees are known for several striking social behaviors, including a complex pattern of behavioral maturation that gives rise to an age-related colony division of labor and a symbolic dance language, by which successful foragers communicate the location of attractive food sources to their nestmates. Our understanding of honey bees is mostly based on studies of the Western honey bee, Apis mellifera, even though there are 9-10 other members of genus Apis, showing interesting variations in social behavior relative to A. mellifera. To facilitate future in-depth genomic and molecular level comparisons of behavior across the genus, we performed a microarray analysis of brain gene expression for A. mellifera and three key species found in Asia, A. cerana, A. florea and A. dorsata. For each species we compared brain gene expression patterns between foragers and adult one-day-old bees on an A. mellifera cDNA microarray and calculated within-species gene expression ratios to facilitate cross-species analysis. The number of cDNA spots showing hybridization fluorescence intensities above the experimental threshold was reduced by an average of 16% in the Asian species compared to A. mellifera, but an average of 71% of genes on the microarray were available for analysis. Brain gene expression profiles between foragers and one-day-olds showed differences that are consistent with a previous study on A. mellifera and were comparable across species. Although 1772 genes showed significant differences in expression between foragers and one-day-olds, only 218 genes showed differences in forager/one-day-old expression between species (p < 0.001). Principal Components Analysis revealed dominant patterns of expression that clearly distinguished between the four species but did not reflect known differences in behavior and ecology. There were species differences in brain expression profiles for functionally related groups of genes. We conclude that the A. mellifera cDNA microarray can be used effectively for cross-species comparisons within the genus. Our results indicate that there is a widespread conservation of the molecular processes in the honey bee brain underlying behavioral maturation. Species differences in brain expression profiles for functionally related groups of genes provide possible clues to the basis of behavioral variation in the genus.

Short communication: Glucose kinetics in dairy heifers limit-fed a low- or high-forage ration at four levels of nitrogen intake

USDA-ARS?s Scientific Manuscript database

The objective of this research was to evaluate the effect of level of forage and nitrogen (N) intake on glucose kinetics in growing dairy heifers. Eight Holstein heifers (beginning at 362 ± 7 kg body weight (BW) and 12.3 ± 0.4 months of age) were fed eight rations according to a split-plot, 4 x 4 La...

Mediating effect of cooperative norm in predicting organizational citizenship behaviors from procedural justice climate.

PubMed

Lin, Shang-Ping; Tang, Ta-Wei; Li, Chao-Hua; Wu, Chien-Ming; Lin, Hsiu-Hsia

2007-08-01

Although the relationships between procedural justice climate and organizational citizenship behaviors have been examined in recent years, little research has explored the mechanism by which procedural justice climate shapes individual employee prosocial behaviors in the workplace. The purpose of this study was to examine the mediating role of a group-level cooperative norm on the relationships between the group-level procedural justice climate and individual-level organizational citizenship behaviors. The survey involved 45 work groups in four different industry fields in Taiwan, including manufacturing, technology, banking, and insurance, and each of the groups was composed of one supervisor and three subordinates. Cross-level analyses using hierarchical linear modeling (HLM) indicated that the cooperative norm fully mediated the relationship between procedural justice climate and individual helping behaviors. Procedural justice climate indirectly affects individual helping behaviors through their effects on the cooperative norm.

Social Network Analysis and Nutritional Behavior: An Integrated Modeling Approach

PubMed Central

Senior, Alistair M.; Lihoreau, Mathieu; Buhl, Jerome; Raubenheimer, David; Simpson, Stephen J.

2016-01-01

Animals have evolved complex foraging strategies to obtain a nutritionally balanced diet and associated fitness benefits. Recent research combining state-space models of nutritional geometry with agent-based models (ABMs), show how nutrient targeted foraging behavior can also influence animal social interactions, ultimately affecting collective dynamics and group structures. Here we demonstrate how social network analyses can be integrated into such a modeling framework and provide a practical analytical tool to compare experimental results with theory. We illustrate our approach by examining the case of nutritionally mediated dominance hierarchies. First we show how nutritionally explicit ABMs that simulate the emergence of dominance hierarchies can be used to generate social networks. Importantly the structural properties of our simulated networks bear similarities to dominance networks of real animals (where conflicts are not always directly related to nutrition). Finally, we demonstrate how metrics from social network analyses can be used to predict the fitness of agents in these simulated competitive environments. Our results highlight the potential importance of nutritional mechanisms in shaping dominance interactions in a wide range of social and ecological contexts. Nutrition likely influences social interactions in many species, and yet a theoretical framework for exploring these effects is currently lacking. Combining social network analyses with computational models from nutritional ecology may bridge this divide, representing a pragmatic approach for generating theoretical predictions for nutritional experiments. PMID:26858671

Nonstructural carbohydrate supplementation of yearling heifers and range beef cows.

PubMed

Bowman, J G P; Sowell, B F; Surber, L M M; Daniels, T K

2004-09-01

A digestion study with 28 yearling heifers (428 +/- 9.9 kg; Exp. 1) and a 2-yr winter grazing trial with 60 crossbred cows (552 +/- 6.9 kg; Exp. 2) were used to determine the effects of level of nonstructural carbohydrate (NSC) supplementation on intake and digestibility of low-quality forage. Treatments were as follows: 1) control, no supplement; 2) 0.32 kg of NSC (1.8 kg/d of soybean hulls and soybean meal; DM basis); 3) 0.64 kg of NSC (1.7 kg/d of wheat middlings; DM basis); and 4) 0.96 kg of NSC (1.7 kg/d of barley and soybean meal; DM basis). Supplements provided 0.34 kg of CP/d and 5.1 Mcal of ME/d. In Exp. 1, heifers were individually fed hay (5.5% CP, DM basis) and their respective supplements in Calan gates for 28 d. Data were analyzed as a completely randomized design. In Exp. 2, cows were individually fed supplement on alternate days, and grazed a single rangeland pasture stocked at 1.8 ha/ animal unit month. Two ruminally cannulated cows were used per treatment to obtain forage extrusa and to measure in situ DM disappearance (DMD) and carboxymethylcellulase (CMCase) activity of particle-associated ruminal microbes. Data were analyzed as a completely randomized design with the effects of treatment, year, and their interaction. In both experiments, Cr2O3 boluses were used to determine fecal output, individual animal was the experimental unit, and contrasts were used to test linear and quadratic effects of NSC level and control vs. supplemented treatments. In Exp. 1, hay and diet DM, NDF, and CP intakes and digestibilities were increased (P < 0.01) by NSC supplementation compared with the control. In Exp. 2, 72-h in situ DMD and CMCase were decreased linearly (P < 0.08) with increasing NSC supplementation. Intake of forage DM, NDF, and CP was decreased linearly (P < 0.01) with increasing NSC supplementation during both years. Supplementation with NSC decreased (P = 0.01) cow BW loss compared with the control in yr 1, whereas in yr 2, cow BW loss was linearly increased (P = 0.03) by increasing NSC supplementation. Supplements containing NSC improved forage digestion and intake when heifers consumed forage deficient in CP relative to energy (digestible OM:CP > 7), but decreased forage digestion and intake when cows grazed forage with adequate CP relative to energy (digestible OM:CP < 7). Forage and supplement digestible OM:CP seemed to be superior predictors of response to supplementation with NSC compared with forage CP levels alone.

Population-level plasticity in foraging behavior of western gulls (Larus occidentalis)

USGS Publications Warehouse

Shaffer, Scott A.; Cockerham, Sue; Warzybok, Pete; Bradley, Russell W.; Jahncke, Jaime; Clatterbuck, Corey A.; Lucia, Magali; Jelincic, Jennifer A.; Cassell, Anne L.; Kelsey, Emily; Adams, Josh

2017-01-01

BackgroundPlasticity in foraging behavior among individuals, or across populations may reduce competition. As a generalist carnivore, western gulls (Larus occidentalis) consume a wide range of marine and terrestrial foods. However, the foraging patterns and habitat selection (ocean or land) of western gulls is not well understood, despite their ubiquity in coastal California. Here, we used GPS loggers to compare the foraging behavior and habitat use of western gulls breeding at two island colonies in central California.ResultsGulls from offshore Southeast Farallon Island (SFI; n = 41 gulls) conducted more oceanic trips (n = 90) of shorter duration (3.8 ± 3.3 SD hours) and distance (27.1 ± 20.3 km) than trips to the mainland (n = 41) which were nearly 4 times longer and 2 times farther away. In contrast, gulls from coastal Año Nuevo Island (ANI; n = 20 gulls) foraged at sites on land more frequently (n = 103) but trip durations (3.6 ± 2.4 h) and distances (20.8 ± 9.4 km) did not differ significantly from oceanic trips (n = 42) where trip durations were only slightly shorter (2.9 ± 2.7 h) and equidistant (20.6 ± 12.1 km). Gulls from both colonies visited more sites while foraging at sea but spent significantly longer (3–5 times) durations at each site visited on land. Foraging at sea was also more random compared to foraging trips over land where gulls from both colonies visited the same sites on multiple trips. The total home range of gulls from SFI (14,230 km2) was 4.5 times larger than that of gulls from ANI, consistent with greater resource competition resulting from a larger abundance of seabirds at SFI.ConclusionsPopulation-level plasticity in foraging behavior was evident and dependent on habitat type. In addition, gulls from SFI were away foraging longer than gulls from ANI (22% vs. 7.5%, respectively), which impacts the defense of territories and attempts at nest predation by conspecifics. Our results can be used to explain lower chick productivity at SFI, and can provide insight into increased gull activity in urban areas.

Spatiotemporal heterogeneity in prey abundance and vulnerability shapes the foraging tactics of an omnivore

USGS Publications Warehouse

Rayl, Nathaniel; Bastille-Rousseau, Guillaume; Organ, John F.; Mumma, Matthew; Mahoney, Shane P.; Soulliere, Colleen; Lewis, Keith; Otto, Robert; Murray, Dennis; Waits, Lisette; Fuller, Todd

2018-01-01

Prey abundance and prey vulnerability vary across space and time, but we know little about how they mediate predator–prey interactions and predator foraging tactics. To evaluate the interplay between prey abundance, prey vulnerability and predator space use, we examined patterns of black bear (Ursus americanus) predation of caribou (Rangifer tarandus) neonates in Newfoundland, Canada using data from 317 collared individuals (9 bears, 34 adult female caribou, 274 caribou calves).During the caribou calving season, we predicted that landscape features would influence calf vulnerability to bear predation, and that bears would actively hunt calves by selecting areas associated with increased calf vulnerability. Further, we hypothesized that bears would dynamically adjust their foraging tactics in response to spatiotemporal changes in calf abundance and vulnerability (collectively, calf availability). Accordingly, we expected bears to actively hunt calves when they were most abundant and vulnerable, but switch to foraging on other resources as calf availability declined.As predicted, landscape heterogeneity influenced risk of mortality, and bears displayed the strongest selection for areas where they were most likely to kill calves, which suggested they were actively hunting caribou. Initially, the per‐capita rate at which bears killed calves followed a type‐I functional response, but as the calving season progressed and calf vulnerability declined, kill rates dissociated from calf abundance. In support of our hypothesis, bears adjusted their foraging tactics when they were less efficient at catching calves, highlighting the influence that predation phenology may have on predator space use. Contrary to our expectations, however, bears appeared to continue to hunt caribou as calf availability declined, but switched from a tactic of selecting areas of increased calf vulnerability to a tactic that maximized encounter rates with calves.Our results reveal that generalist predators can dynamically adjust their foraging tactics over short time‐scales in response to changing prey abundance and vulnerability. Further, they demonstrate the utility of integrating temporal dynamics of prey availability into investigations of predator–prey interactions, and move towards a mechanistic understanding of the dynamic foraging tactics of a large omnivore.

Spatiotemporal heterogeneity in prey abundance and vulnerability shapes the foraging tactics of an omnivore.

PubMed

Rayl, Nathaniel D; Bastille-Rousseau, Guillaume; Organ, John F; Mumma, Matthew A; Mahoney, Shane P; Soulliere, Colleen E; Lewis, Keith P; Otto, Robert D; Murray, Dennis L; Waits, Lisette P; Fuller, Todd K

2018-05-01

Prey abundance and prey vulnerability vary across space and time, but we know little about how they mediate predator-prey interactions and predator foraging tactics. To evaluate the interplay between prey abundance, prey vulnerability and predator space use, we examined patterns of black bear (Ursus americanus) predation of caribou (Rangifer tarandus) neonates in Newfoundland, Canada using data from 317 collared individuals (9 bears, 34 adult female caribou, 274 caribou calves). During the caribou calving season, we predicted that landscape features would influence calf vulnerability to bear predation, and that bears would actively hunt calves by selecting areas associated with increased calf vulnerability. Further, we hypothesized that bears would dynamically adjust their foraging tactics in response to spatiotemporal changes in calf abundance and vulnerability (collectively, calf availability). Accordingly, we expected bears to actively hunt calves when they were most abundant and vulnerable, but switch to foraging on other resources as calf availability declined. As predicted, landscape heterogeneity influenced risk of mortality, and bears displayed the strongest selection for areas where they were most likely to kill calves, which suggested they were actively hunting caribou. Initially, the per-capita rate at which bears killed calves followed a type-I functional response, but as the calving season progressed and calf vulnerability declined, kill rates dissociated from calf abundance. In support of our hypothesis, bears adjusted their foraging tactics when they were less efficient at catching calves, highlighting the influence that predation phenology may have on predator space use. Contrary to our expectations, however, bears appeared to continue to hunt caribou as calf availability declined, but switched from a tactic of selecting areas of increased calf vulnerability to a tactic that maximized encounter rates with calves. Our results reveal that generalist predators can dynamically adjust their foraging tactics over short time-scales in response to changing prey abundance and vulnerability. Further, they demonstrate the utility of integrating temporal dynamics of prey availability into investigations of predator-prey interactions, and move towards a mechanistic understanding of the dynamic foraging tactics of a large omnivore. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

(Evolutionary) Theories of warfare in preindustrial (foraging) societies.

PubMed

van der Dennen, Johan M G

2002-12-01

I present an inventory of theories of war causation (and on the origin of war) in preindustrial (traditional, foraging, 'primitive', hunter-gatherer, band- and tribe-level) societies, with emphasis on the roles of natural selection, sexual selection and kin selection. Also the school of sociocultural evolution is briefly discussed.

Foraging interactions of small Hawaiian forest birds

Treesearch

C. John Ralph; Barry R. Noon

1986-01-01

In a search for competition, limiting factors, and other patterns in a community of small passerine birds in Hawaii, we recorded the foraging behaviors, resource abundances, and climatic variables believed to influence resource levels. Some definite patterns were found, showing that the rare, endangered birds were specialists; however, some specialists were quite...

Isotopic Differences between Forage Consumed by a Large Herbivore in Open, Closed, and Coastal Habitats: New Evidence from a Boreal Study System.

PubMed

Giroux, Marie-Andrée; Valiquette, Éliane; Tremblay, Jean-Pierre; Côté, Steeve D

2015-01-01

Documenting habitat-related patterns in foraging behaviour at the individual level and over large temporal scales remains challenging for large herbivores. Stable isotope analysis could represent a valuable tool to quantify habitat-related foraging behaviour at the scale of individuals and over large temporal scales in forest dwelling large herbivores living in coastal environments, because the carbon (δ13C) or nitrogen (δ15N) isotopic signatures of forage can differ between open and closed habitats or between terrestrial and littoral forage, respectively. Here, we examined if we could detect isotopic differences between the different assemblages of forage taxa consumed by white-tailed deer that can be found in open, closed, supralittoral, and littoral habitats. We showed that δ13C of assemblages of forage taxa were 3.0 ‰ lower in closed than in open habitats, while δ15N were 2.0 ‰ and 7.4 ‰ higher in supralittoral and littoral habitats, respectively, than in terrestrial habitats. Stable isotope analysis may represent an additional technique for ecologists interested in quantifiying the consumption of terrestrial vs. marine autotrophs. Yet, given the relative isotopic proximity and the overlap between forage from open, closed, and supralittoral habitats, the next step would be to determine the potential to estimate their contribution to herbivore diet.

Foraging in the Darkness of the Southern Ocean: Influence of Bioluminescence on a Deep Diving Predator

PubMed Central

Vacquié-Garcia, Jade; Royer, François; Dragon, Anne-Cécile; Viviant, Morgane; Bailleul, Frédéric; Guinet, Christophe

2012-01-01

How non-echolocating deep diving marine predators locate their prey while foraging remains mostly unknown. Female southern elephant seals (SES) (Mirounga leonina) have vision adapted to low intensity light with a peak sensitivity at 485 nm. This matches the wavelength of bioluminescence produced by a large range of marine organisms including myctophid fish, SES’s main prey. In this study, we investigated whether bioluminescence provides an accurate estimate of prey occurrence for SES. To do so, four SES were satellite-tracked during their post-breeding foraging trip and were equipped with Time-Depth-Recorders that also recorded light levels every two seconds. A total of 3386 dives were processed through a light-treatment model that detected light events higher than ambient level, i.e. bioluminescence events. The number of bioluminescence events was related to an index of foraging intensity for SES dives deep enough to avoid the influence of natural ambient light. The occurrence of bioluminescence was found to be negatively related to depth both at night and day. Foraging intensity was also positively related to bioluminescence both during day and night. This result suggests that bioluminescence likely provides SES with valuable indications of prey occurrence and might be a key element in predator-prey interactions in deep-dark marine environments. PMID:22952706

Are corticosterone levels a good indicator of food availability and reproductive performance in a kittiwake colony?

USGS Publications Warehouse

Lanctot, Richard B.; Hatch, Shyla A.; Gill, Verena A.; Eens, Marcel

2003-01-01

We evaluated the use of corticosterone to gauge forage availability and predict reproductive performance in black-legged kittiwakes (Rissa tridactyla) breeding in Alaska during 1999 and 2000. We modeled the relationship between baseline levels of corticosterone and a suite of individual and temporal characteristics of the sampled birds. We also provided supplemental food to a sample of pairs and compared their corticosterone levels with that of pairs that were not fed. Corticosterone levels were a good predictor of forage availability in some situations, although inconsistencies between corticosterone levels and reproductive performance of fed and unfed kittiwakes suggested that this was not always the case. In general, higher corticosterone levels were found in birds that lacked breeding experience and in birds sampled shortly after arriving from their wintering grounds. All parameters investigated, however, explained only a small proportion of the variance in corticosterone levels. We also investigated whether corticosterone, supplemental feeding, year of the study, breeding experience, body weight, and sex of a bird were able to predict laying, hatching, and fledging success in kittiwakes. Here, breeding experience, year of the study, and body weight were the best predictors of a bird’s performance. Corticosterone level and supplemental feeding were good predictors of kittiwake reproductive performance in some cases. For example, corticosterone levels of birds sampled during the arrival stage reliably predicted laying success, but were less reliable at predicting hatching and fledging success. Counts of active nests with eggs or chicks may be more reliable estimates of the actual productivity of the colony. Supplemental feeding had strong effects on kittiwake productivity when natural forage was poor, but had little effect when natural forage was plentiful.

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.142 - 2,4-D; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

....3 Cattle, meat byproducts, except kidney 0.3 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 50 Corn, pop, grain 0.05 Corn, pop, stover 50 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cranberry 0.5 Fish 0.1 Fruit, citrus, group 10...

40 CFR 180.629 - Flutriafol; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... commodities: Commodity Parts per million Corn, sweet, forage 0.09 Corn, sweet, kernel plus cob with husk... Cattle, meat byproducts 0.07 Corn, field, forage 0.75 Corn, field, grain 0.01 Corn, field, refined oil 0.02 Corn, field, stover 1.5 Corn, pop 0.01 Corn, pop, stover 1.5 Fruit, pome, group 11-09 0.40 Fruit...

40 CFR 180.142 - 2,4-D; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

....3 Cattle, meat byproducts, except kidney 0.3 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 50 Corn, pop, grain 0.05 Corn, pop, stover 50 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cranberry 0.5 Fish 0.1 Fruit, citrus, group 10...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.142 - 2,4-D; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

....3 Cattle, meat byproducts, except kidney 0.3 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 50 Corn, pop, grain 0.05 Corn, pop, stover 50 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cranberry 0.5 Fish 0.1 Fruit, citrus, group 10...

The relationship between blood metabolites and hormones with intake, gain, and efficiency in beef cattle consuming forage then concentrate diets

USDA-ARS?s Scientific Manuscript database

The objective of this experiment was to determine if selected blood metabolites and hormones are related to DMI, ADG, and efficiency in cattle consuming a variety of diets. Approximately 50-d postweaning, a group of crossbred heifers (n=76) were fed a forage-based diet containing (DM basis) 69.8% co...

Predation risk and elk-aspen foraging patterns

Treesearch

Clifford A. White; Michael C. Feller

2001-01-01

Elk-aspen foraging patterns may be influenced by cover type, distance from roads or trails, the type of user on road or trail (park visitor, human hunter, or predator), and two general states of aspen condition (open-grown or thicket). Pellet group and browse utilization transects in the Canadian Rockies showed that elk were attracted to roads used by park visitors and...

Stable producer–scrounger dynamics in wild birds: sociability and learning speed covary with scrounging behaviour

PubMed Central

Morand-Ferron, J.

2017-01-01

There has been extensive game-theoretic modelling of conditions leading to equilibria of producer–scrounger dichotomies in groups. However there is a surprising paucity of experimental evidence in wild populations. Here, we examine producer–scrounger games in five subpopulations of birds feeding at a socially learnt foraging task. Over four weeks, a bimodal distribution of producers and scroungers emerged in all areas, with pronounced and consistent individual tactic specialization persisting over 3 years. Tactics were unrelated to exploratory personality, but correlated with latency to contact and learn the foraging task, with the late arrivers and slower learners more likely to adopt the scrounging role. Additionally, the social environment was also important: at the broad scale, larger subpopulations with a higher social density contained proportionally more scroungers, while within subpopulations scroungers tended to be central in the social network and be observed in larger foraging flocks. This study thus provides a rare example of a stable, dimorphic distribution of producer–scrounger tactics in a wild population. It further gives support across multiple scales for a major prediction of social foraging theory; that the frequency of scroungers increases with group size. PMID:28404775

Stable producer-scrounger dynamics in wild birds: sociability and learning speed covary with scrounging behaviour.

PubMed

Aplin, L M; Morand-Ferron, J

2017-04-12

There has been extensive game-theoretic modelling of conditions leading to equilibria of producer-scrounger dichotomies in groups. However there is a surprising paucity of experimental evidence in wild populations. Here, we examine producer-scrounger games in five subpopulations of birds feeding at a socially learnt foraging task. Over four weeks, a bimodal distribution of producers and scroungers emerged in all areas, with pronounced and consistent individual tactic specialization persisting over 3 years. Tactics were unrelated to exploratory personality, but correlated with latency to contact and learn the foraging task, with the late arrivers and slower learners more likely to adopt the scrounging role. Additionally, the social environment was also important: at the broad scale, larger subpopulations with a higher social density contained proportionally more scroungers, while within subpopulations scroungers tended to be central in the social network and be observed in larger foraging flocks. This study thus provides a rare example of a stable, dimorphic distribution of producer-scrounger tactics in a wild population. It further gives support across multiple scales for a major prediction of social foraging theory; that the frequency of scroungers increases with group size. © 2017 The Authors.

Red-cockaded woodpecker male/female foraging differences in young forest stands.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franzreb, Kathleen, E.

2010-07-01

ABSTRACT The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinus spp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in contrast to earlier foraging behavior studies that focused on more mature forest. The Redcockaded Woodpecker at the Savannah River site is intensively managed including monitoring, translocation, and installation of artificial cavity inserts for roosting and nesting. Over a 3-year period, 6,407 foraging observations covering sevenmore » woodpecker family groups were recorded during all seasons of the year and all times of day. The most striking differences occurred in foraging method (males usually scaled [45% of observations] and females mostly probed [47%]),substrate used (females had a stronger preference [93%] for the trunk than males [79%]), and foraging height from the ground (mean 6 SE foraging height was higher for males [11.1 6 0.5 m] than females [9.8 6 0.5 m]). Niche overlap between males and females was lowest for substrate (85.6%) and foraging height (87.8%), and highest for tree species (99.0%), tree condition (98.3%), and tree height (96.4%). Both males and females preferred to forage in older, large pine trees. The habitat available at the Savannah River Site was considerably younger than at most other locations, but the pattern of male/female habitat partitioning observed was similar to that documented elsewhere within the range attesting to the species’ ability to adjust behaviorally.« less

Changes in intrapopulation resource use patterns of an endangered raptor in response to a disease-mediated crash in prey abundance.

PubMed

Moleón, Marcos; Sebastián-González, Esther; Sánchez-Zapata, José A; Real, Joan; Pires, Mathias M; Gil-Sánchez, José M; Bautista, Jesús; Palma, Luís; Bayle, Patrick; Guimarães, Paulo R; Beja, Pedro

2012-11-01

1. A long-standing question in ecology is how natural populations respond to a changing environment. Emergent optimal foraging theory-based models for individual variation go beyond the population level and predict how its individuals would respond to disturbances that produce changes in resource availability. 2. Evaluating variations in resource use patterns at the intrapopulation level in wild populations under changing environmental conditions would allow to further advance in the research on foraging ecology and evolution by gaining a better idea of the underlying mechanisms explaining trophic diversity. 3. In this study, we use a large spatio-temporal scale data set (western continental Europe, 1968-2006) on the diet of Bonelli's Eagle Aquila fasciata breeding pairs to analyse the predator trophic responses at the intrapopulation level to a prey population crash. In particular, we borrow metrics from studies on network structure and intrapopulation variation to understand how an emerging infectious disease [the rabbit haemorrhagic disease (RHD)] that caused the density of the eagle's primary prey (rabbit Oryctolagus cuniculus) to dramatically drop across Europe impacted on resource use patterns of this endangered raptor. 4. Following the major RHD outbreak, substantial changes in Bonelli's Eagle's diet diversity and organisation patterns at the intrapopulation level took place. Dietary variation among breeding pairs was larger after than before the outbreak. Before RHD, there were no clusters of pairs with similar diets, but significant clustering emerged after RHD. Moreover, diets at the pair level presented a nested pattern before RHD, but not after. 5. Here, we reveal how intrapopulation patterns of resource use can quantitatively and qualitatively vary, given drastic changes in resource availability. 6. For the first time, we show that a pathogen of a prey species can indirectly impact the intrapopulation patterns of resource use of an endangered predator. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Sodium Butyrate Ameliorates High-Concentrate Diet-Induced Inflammation in the Rumen Epithelium of Dairy Goats.

PubMed

Dai, Hongyu; Liu, Xinxin; Yan, Jinyu; Aabdin, Zain Ul; Bilal, Muhammad Shahid; Shen, Xiangzhen

2017-01-25

To investigate the effect of sodium butyrate on high-concentrate diet-induced local inflammation of the rumen epithelium, 18 midlactating dairy goats were randomly assigned to 3 groups: a low-concentrate diet group as the control (concentrate:forage = 4:6), a high-concentrate (HC) diet group (concentrate:forage = 6:4), and a sodium butyrate (SB) group (concentrate:forage = 6:4, with 1% SB by weight). The results showed that, with the addition of sodium butyrate, the concentration of lipopolysaccharide (LPS) in rumen fluid (2.62 × 10 4 ± 2.90 × 10 3 EU/mL) was significantly lower than that in the HC group (4.03 × 10 4 ± 2.77 × 10 3 EU/mL). The protein abundance of pp65, gene expression of proinflammatory cytokines, and activity of myeloperoxidase (MPO) and matrix metalloproteinase (MMP)-2,9 in the rumen epithelium were significantly down-regulated by SB compared with those in the HC group. With sodium butyrate administration, the concentration of NH3-N (19.2 ± 0.890 mM) in the rumen fluid was significantly higher than that for the HC group (12.7 ± 1.38 mM). Severe disruption of the rumen epithelium induced by HC was also ameliorated by dietary SB. Therefore, local inflammation and disruption of the rumen epithelium induced by HC were alleviated with SB administration.

Alfalfa (Medicago sativa L.).

PubMed

Fu, Chunxiang; Hernandez, Timothy; Zhou, Chuanen; Wang, Zeng-Yu

2015-01-01

Alfalfa (Medicago sativa L.) is a high-quality forage crop widely grown throughout the world. This chapter describes an efficient protocol that allows for the generation of large number of transgenic alfalfa plants by sonication-assisted Agrobacterium-mediated transformation. Binary vectors carrying different selectable marker genes that confer resistance to phosphinothricin (bar), kanamycin (npt II), or hygromycin (hph) were used to generate transgenic alfalfa plants. Intact trifoliates collected from clonally propagated plants in the greenhouse were sterilized with bleach and then inoculated with Agrobacterium strain EHA105. More than 80 % of infected leaf pieces could produce rooted transgenic plants in 4-5 months after Agrobacterium-mediated transformation.

Transcriptional regulators transforming growth factor-beta 1 and estrogen-related receptor-alpha identified as putative mediators of calf rumen epithelial tissue development and function during weaning

USDA-ARS?s Scientific Manuscript database

Molecular mechanisms controlling rumen epithelial development at weaning remain largely unknown. To identify gene networks and regulatory factors responsive to concentrate versus forage feeding at weaning, Holstein bull calves (n = 18) were fed commercial milk replacer only (MRO) until 42 d of age. ...

Nitrate foraging by Arabidopsis roots is mediated by the transcription factor TCP20 through the systemic signaling pathway

PubMed Central

Guan, Peizhu; Wang, Rongchen; Nacry, Philippe; Breton, Ghislain; Kay, Steve A.; Pruneda-Paz, Jose L.; Davani, Ariea; Crawford, Nigel M.

2014-01-01

To compete for nutrients in diverse soil microenvironments, plants proliferate lateral roots preferentially in nutrient-rich zones. For nitrate, root foraging involves local and systemic signaling; however, little is known about the genes that function in the systemic signaling pathway. By using nitrate enhancer DNA to screen a library of Arabidopsis transcription factors in the yeast one-hybrid system, the transcription factor gene TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR1-20 (TCP20) was identified. TCP20, which belongs to an ancient, plant-specific gene family that regulates shoot, flower, and embryo development, was implicated in nitrate signaling by its ability to bind DNA in more than 100 nitrate-regulated genes. Analysis of insertion mutants of TCP20 showed that they had normal primary and lateral root growth on homogenous nitrate media but were impaired in preferential lateral root growth (root foraging) on heterogeneous media in split-root plates. Inhibition of preferential lateral root growth was still evident in the mutants even when ammonium was uniformly present in the media, indicating that the TCP20 response was to nitrate. Comparison of tcp20 mutants with those of nlp7 mutants, which are defective in local control of root growth but not in the root-foraging response, indicated that TCP20 function is independent of and distinct from NLP7 function. Further analysis showed that tcp20 mutants lack systemic control of root growth regardless of the local nitrate concentrations. These results indicate that TCP20 plays a key role in the systemic signaling pathway that directs nitrate foraging by Arabidopsis roots. PMID:25288754

Movements of wintering surf scoters: Predator responses to different prey landscapes

USGS Publications Warehouse

Kirk, M.; Esler, Daniel N.; Iverson, S.A.; Boyd, W.S.

2008-01-01

The distribution of predators is widely recognized to be intimately linked to the distribution of their prey. Foraging theory suggests that predators will modify their behaviors, including movements, to optimize net energy intake when faced with variation in prey attributes or abundance. While many studies have documented changes in movement patterns of animals in response to temporal changes in food, very few have contrasted movements of a single predator species naturally occurring in dramatically different prey landscapes. We documented variation in the winter movements, foraging range size, site fidelity, and distribution patterns of a molluscivorous sea duck, the surf scoter (Melanitta perspicillata), in two areas of coastal British Columbia with very different shellfish prey features. Baynes Sound has extensive tidal flats with abundant clams, which are high-quality and temporally stable prey for scoters. Malaspina Inlet is a rocky fjord-like inlet where scoters consume mussels that are superabundant and easily accessible in some patches but are heavily depleted over the course of winter. We used radio telemetry to track surf scoter movements in both areas and found that in the clam habitats of Baynes Sound, surf scoters exhibited limited movement, small winter ranges, strong foraging site fidelity, and very consistent distribution patterns. By contrast, in mussel habitats in the Malaspina Inlet, surf scoters displayed more movement, larger ranges, little fidelity to specific foraging sites, and more variable distribution patterns. We conclude that features associated with the different prey types, particularly the higher depletion rates of mussels, strongly influenced seasonal space use patterns. These findings are consistent with foraging theory and confirm that predator behavior, specifically movements, is environmentally mediated. ?? 2008 Springer-Verlag.

Impact of logging on the foraging behaviour of two sympatric species of Couas (Coua coquereli and Coua gigas) in the western dry forest of Madagascar.

PubMed

Chouteau, Philippe

2009-06-01

Two ground-dwelling couas species, Coquerel's Coua Coua coquereli and Giant Coua Coua gigas, live in sympatry in the dry forest of Madagascar. These birds are typically insectivorous and mainly feed at ground level. The two species differ by size but have the same morphology, suggesting they have the same physical attributes for foraging and prey capture. To test if the two species have the same foraging behaviour, and also to know how habitat disturbance due to logging could affect their foraging behaviour, I compared and analysed the foraging strategies of both species in two different dry forest habitats: unlogged and logged. The two species differed in their foraging behaviour between the two habitats, mainly by the ability to climb in the vegetation, and by the technique used by both species. Coquerel's Coua used more often gleaning and probing in the unlogged forest, while Giant Coua used lunge more often in this habitat. The giant Coua used also more often leaves as a substrate in the logged forest. Some modifications in the diet have been recorded too. These results suggest that anthropogenic disturbance of forest does influence the foraging behaviour of the terrestrial couas species living in the dry forest in Madagascar.

Stingless bees (Melipona subnitida) adjust brood production rather than foraging activity in response to changes in pollen stores.

PubMed

Maia-Silva, Camila; Hrncir, Michael; Imperatriz-Fonseca, Vera Lucia; Schorkopf, Dirk Louis P

2016-10-01

Highly eusocial bees (honey bees and stingless bees) sustain their colonies through periods of resource scarcity by food stored within the nest. The protein supply necessary for successful brood production is ensured through adjustments of the colonies' pollen foraging according to the availability of this resource in the environment. In honey bees Apis mellifera, in addition, pollen foraging is regulated through the broods' demand for this resource. Here, we investigated the influence of the colony's pollen store level on pollen foraging and brood production in stingless bees (Melipona subnitida). When pollen was added to the nests, colonies increased their brood production and reduced their pollen foraging within 24 h. On the other hand, when pollen reserves were removed, colonies significantly reduced their brood production. In strong contrast to A. mellifera; however, M. subnitida did not significantly increase its pollen foraging activity under poor pollen store conditions. This difference concerning the regulation of pollen foraging may be due to differences regarding the mechanism of brood provisioning. Honey bees progressively feed young larvae and, consequently, require a constant pollen supply. Stingless bees, by contrast, mass-provision their brood cells and temporary absence of pollen storage will not immediately result in substantial brood loss.

Nutritional Characteristics of Forage Grown in South of Benin

PubMed Central

Musco, Nadia; Koura, Ivan B.; Tudisco, Raffaella; Awadjihè, Ghislain; Adjolohoun, Sebastien; Cutrignelli, Monica I.; Mollica, Maria Pina; Houinato, Marcel; Infascelli, Federico; Calabrò, Serena

2016-01-01

In order to provide recommendations on the most useful forage species to smallholder farmers, eleven grass and eleven legume forages grown in Abomey-Calavi in Republic of Benin were investigated for nutritive value (i.e. chemical composition and energy content) and fermentation characteristics (i.e. gas and volatile fatty acid production, organic matter degradability). The in vitro gas production technique was used, incubating the forages for 120 h under anaerobic condition with buffalo rumen fluid. Compared to legume, tropical grass forages showed lower energy (8.07 vs 10.57 MJ/kg dry matter [DM]) and crude protein level (16.10% vs 19.91% DM) and higher cell wall content (neutral detergent fiber: 63.8% vs 40.45% DM), respectively. In grass forages, the chemical composition showed a quite high crude protein content; the in vitro degradability was slightly lower than the range of tropical pasture. The woody legumes were richer in protein and energy and lower in structural carbohydrates than herbaceous plants, however, their in vitro results are influenced by the presence of complex compounds (i.e. tannins). Significant correlations were found between chemical composition and in vitro fermentation characteristics. The in vitro gas production method appears to be a suitable technique for the evaluation of the nutritive value of forages in developing countries. PMID:26732328

Does Group-Level Commitment Predict Employee Well-Being?: A Prospective Analysis.

PubMed

Clausen, Thomas; Christensen, Karl Bang; Nielsen, Karina

2015-11-01

To investigate the links between group-level affective organizational commitment (AOC) and individual-level psychological well-being, self-reported sickness absence, and sleep disturbances. A total of 5085 care workers from 301 workgroups in the Danish eldercare services participated in both waves of the study (T1 [2005] and T2 [2006]). The three outcomes were analyzed using linear multilevel regression analysis, multilevel Poisson regression analysis, and multilevel logistic regression analysis, respectively. Group-level AOC (T1) significantly predicted individual-level psychological well-being, self-reported sickness absence, and sleep disturbances (T2). The association between group-level AOC (T1) and psychological well-being (T2) was fully mediated by individual-level AOC (T1), and the associations between group-level AOC (T1) and self-reported sickness absence and sleep disturbances (T2) were partially mediated by individual-level AOC (T1). Group-level AOC is an important predictor of employee well-being in contemporary health care organizations.

Modeling the origins of mammalian sociality: moderate evidence for matrilineal signatures in mouse lemur vocalizations.

PubMed

Kessler, Sharon E; Radespiel, Ute; Hasiniaina, Alida I F; Leliveld, Lisette M C; Nash, Leanne T; Zimmermann, Elke

2014-02-20

Maternal kin selection is a driving force in the evolution of mammalian social complexity and it requires that kin are distinctive from nonkin. The transition from the ancestral state of asociality to the derived state of complex social groups is thought to have occurred via solitary foraging, in which individuals forage alone, but, unlike the asocial ancestors, maintain dispersed social networks via scent-marks and vocalizations. We hypothesize that matrilineal signatures in vocalizations were an important part of these networks. We used the solitary foraging gray mouse lemur (Microcebus murinus) as a model for ancestral solitary foragers and tested for matrilineal signatures in their calls, thus investigating whether such signatures are already present in solitary foragers and could have facilitated the kin selection thought to have driven the evolution of increased social complexity in mammals. Because agonism can be very costly, selection for matrilineal signatures in agonistic calls should help reduce agonism between unfamiliar matrilineal kin. We conducted this study on a well-studied population of wild mouse lemurs at Ankarafantsika National Park, Madagascar. We determined pairwise relatedness using seven microsatellite loci, matrilineal relatedness by sequencing the mitrochondrial D-loop, and sleeping group associations using radio-telemetry. We recorded agonistic calls during controlled social encounters and conducted a multi-parametric acoustic analysis to determine the spectral and temporal structure of the agonistic calls. We measured 10 calls for each of 16 females from six different matrilineal kin groups. Calls were assigned to their matriline at a rate significantly higher than chance (pDFA: correct = 47.1%, chance = 26.7%, p = 0.03). There was a statistical trend for a negative correlation between acoustic distance and relatedness (Mantel Test: g = -1.61, Z = 4.61, r = -0.13, p = 0.058). Mouse lemur agonistic calls are moderately distinctive by matriline. Because sleeping groups consisted of close maternal kin, both genetics and social learning may have generated these acoustic signatures. As mouse lemurs are models for solitary foragers, we recommend further studies testing whether the lemurs use these calls to recognize kin. This would enable further modeling of how kin recognition in ancestral species could have shaped the evolution of complex sociality.

Cervid forage utilization in noncommercially thinned ponderosa pine forests

USGS Publications Warehouse

Gibbs, M.C.; Jenks, J.A.; Deperno, C.S.; Sowell, B.F.; Jenkins, Kurt J.

2004-01-01

To evaluate effects of noncommercial thinning, utilization of forages consumed by elk (Cervus elaphus L.), mule deer (Odocoileus hemionus Raf.), and white-tailed deer (Odocoileus virginianus Raf.) was measured in ponderosa pine (Pinus ponderosa P. & C. Lawson) stands in Custer State Park, S. D. Treatments consisted of unthinned (control; 22 to 32 m2/ha basal area), moderately thinned (12 to 22 m2/ha basal area), and heavily thinned (3 to 13 m2/ha basal area) stands of ponderosa pine. During June, July, and August, 1991 and 1992, about 7,000 individual plants were marked along permanent transects and percent-weight-removed by grazing was ocularly estimated. Sample plots were established along transects and plants within plots were clipped to estimate standing biomass. Pellet groups were counted throughout the study area to determine summer habitat use of elk and deer. Diet composition was evaluated using microhistological analysis of fecal samples. Average percent-weight-removed from all marked plants and percent-plants-grazed were used to evaluate forage utilization. Standing biomass of graminoids, shrubs, and forbs increased (P 0.05) across treatments. Forb use averaged less than 5% within sampling periods when measured as percent-weight-removed and percent-of-plants grazed and did not differ among treatments. Results of pellet group surveys indicated that cervids were primarily using meadow habitats. When averaged over the 2 years, forbs were the major forage class in deer diets, whereas graminoids were the major forage class in diets of elk.

Responses to sugar and sugar receptor gene expression in different social roles of the honeybee (Apis mellifera).

PubMed

Değirmenci, Laura; Thamm, Markus; Scheiner, Ricarda

2018-04-01

Honeybees (Apis mellifera) are well-known for their sophisticated division of labor with each bee performing sequentially a series of social tasks. Colony organization is largely based on age-dependent division of labor. While bees perform several tasks inside the hive such as caring for brood ("nursing"), cleaning or sealing brood cells or producing honey, older bees leave to colony to collect pollen (proteins) and nectar (carbohydrates) as foragers. The most pronounced behavioral transition occurs when nurse bees become foragers. For both social roles, the detection and evaluation of sugars is decisive for optimal task performance. Nurse bees rely on their gustatory senses to prepare brood food, while foragers evaluate a nectar source before starting to collect food from it. To test whether social organization is related to differential sensing of sugars we compared the taste of nurse bees and foragers for different sugars. Searching for molecular correlates for differences in sugar perception, we further quantified expression of gustatory receptor genes in both behavioral groups. Our results demonstrate that nurse bees and foragers perceive and evaluate different sugars differently. Both groups, however, prefer sucrose over fructose. At least part of the taste differences between social roles could be related to a differential expression of taste receptors in the antennae and brain. Our results suggest that differential expression of sugar receptor genes might be involved in regulating division of labor through nutrition-related signaling pathways. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Rosmarinus officinalis L. essential oils supplementation on digestion, colostrum production of dairy ewes and lamb mortality and growth.

PubMed

Smeti, Samir; Joy, Margalida; Hajji, Hadhami; Alabart, José Luis; Muñoz, Fernando; Mahouachi, Mokhtar; Atti, Naziha

2015-07-01

The aim of this study was to evaluate the effect of rosemary essential oils (REO) and the forage nature on ewes' performances, immune response and lambs' growth and mortality. Forty-eight dairy ewes (Sicilo-Sarde) were fed oat-hay or oat-silage supplemented with 400 g of concentrate during pregnancy and 600 g during postpartum. The experimental concentrate contained the same mixture as the control (barley, soybean meal and mineral vitamin supplement) more 0.6 g/kg of REO. Two groups were obtained with each forage (Hay groups: H-C and H-REO; Silage groups: S-C and S-REO). REO increased the dry matter (DM) intake, the nitrogen intake and retention being higher with the silage groups (P < 0.05). REO increased solid non-fat (P = 0.004) and fat contents of colostrum which was higher with hay (P = 0.002). REO decreased lamb mortality (P < 0.05) which averaged 21% for control groups and 6% for H-REO, while no mortality was recorded with S-REO. REO dietary supply improved forage intake and tended to ameliorate colostrum production; it could be a natural additive to improve ewes' performances. © 2015 Japanese Society of Animal Science.

The innate responses of bumble bees to flower patterns: separating the nectar guide from the nectary changes bee movements and search time

NASA Astrophysics Data System (ADS)

Goodale, Eben; Kim, Edward; Nabors, Annika; Henrichon, Sara; Nieh, James C.

2014-06-01

Nectar guides can enhance pollinator efficiency and plant fitness by allowing pollinators to more rapidly find and remember the location of floral nectar. We tested if a radiating nectar guide around a nectary would enhance the ability of naïve bumble bee foragers to find nectar. Most experiments that test nectar guide efficacy, specifically radiating linear guides, have used guides positioned around the center of a radially symmetric flower, where nectaries are often found. However, the flower center may be intrinsically attractive. We therefore used an off-center guide and nectary and compared "conjunct" feeders with a nectar guide surrounding the nectary to "disjunct" feeders with a nectar guide separated from the nectary. We focused on the innate response of novice bee foragers that had never previously visited such feeders. We hypothesized that a disjunct nectar guide would conflict with the visual information provided by the nectary and negatively affect foraging. Approximately, equal numbers of bumble bees ( Bombus impatiens) found nectar on both feeder types. On disjunct feeders, however, unsuccessful foragers spent significantly more time (on average 1.6-fold longer) searching for nectar than any other forager group. Successful foragers on disjunct feeders approached these feeders from random directions unlike successful foragers on conjunct feeders, which preferentially approached the combined nectary and nectar guide. Thus, the nectary and a surrounding nectar guide can be considered a combination of two signals that attract naïve foragers even when not in the floral center.

The innate responses of bumble bees to flower patterns: separating the nectar guide from the nectary changes bee movements and search time.

PubMed

Goodale, Eben; Kim, Edward; Nabors, Annika; Henrichon, Sara; Nieh, James C

2014-06-01

Nectar guides can enhance pollinator efficiency and plant fitness by allowing pollinators to more rapidly find and remember the location of floral nectar. We tested if a radiating nectar guide around a nectary would enhance the ability of naïve bumble bee foragers to find nectar. Most experiments that test nectar guide efficacy, specifically radiating linear guides, have used guides positioned around the center of a radially symmetric flower, where nectaries are often found. However, the flower center may be intrinsically attractive. We therefore used an off-center guide and nectary and compared "conjunct" feeders with a nectar guide surrounding the nectary to "disjunct" feeders with a nectar guide separated from the nectary. We focused on the innate response of novice bee foragers that had never previously visited such feeders. We hypothesized that a disjunct nectar guide would conflict with the visual information provided by the nectary and negatively affect foraging. Approximately, equal numbers of bumble bees (Bombus impatiens) found nectar on both feeder types. On disjunct feeders, however, unsuccessful foragers spent significantly more time (on average 1.6-fold longer) searching for nectar than any other forager group. Successful foragers on disjunct feeders approached these feeders from random directions unlike successful foragers on conjunct feeders, which preferentially approached the combined nectary and nectar guide. Thus, the nectary and a surrounding nectar guide can be considered a combination of two signals that attract naïve foragers even when not in the floral center.

Dairy cows fed on tropical legume forages: effects on milk yield, nutrients use efficiency and profitability.

PubMed

Castro-Montoya, J M; García, R A; Ramos, R A; Flores, J M; Alas, E A; Corea, E E

2018-04-01

Two trials with multiparous dairy cows were conducted. Experiment 1 tested the effects of increasing forage proportion in the diet (500, 600, and 700 g/kg DM) when a mixed sorghum (Sorghum bicolor) and jackbean (Cannavalia ensiformis) silage was used as forage. Experiment 2 studied the substitution of sorghum silage and soybean meal by jackbean silage or fresh cowpea (Vigna unguiculata) forage in the diet. All diets were iso-energetic and iso-proteic. In each experiment, 30 cows were used and separated into three groups. In experiment 1, there were no differences in dry matter intake (DMI), milk yield (MY), or apparent total tract digestibility (aTTd) among the three diets, but milk fat content increased with increasing forage proportion, even though the similar neutral detergent fiber of all diets. Nitrogen use efficiency was highest in the diet containing 600 g forage/kg DM, and some evidence was observed for a better profitability with this forage proportion. In experiment 2, feeding legumes increased DMI despite no effects on aTTd. Milk yield increased in line with DMI, with a larger increase for the fresh cowpea. Nitrogen use efficiency and milk composition were not affected by the diets. The increased MY and lower feed costs increased the economic benefits when feeding legumes, particularly when feeding fresh cowpea. Feeding fresh cowpea or jackbean silage to dairy cows appears to be an alternative to soybean as protein source, ideally at a forage proportions of 600 g/kg DM, without altering milk yield and quality and increasing the farm profitability.

The Role of Natural Enemy Foraging Guilds in Controlling Cereal Aphids in Michigan Wheat

PubMed Central

Safarzoda, Shahlo; Bahlai, Christine A.; Fox, Aaron F.; Landis, Douglas A.

2014-01-01

Insect natural enemies (predators and parasitoids) provide important ecosystem services by suppressing populations of insect pests in many agricultural crops. However, the role of natural enemies against cereal aphids in Michigan winter wheat (Triticum aestivum L.) is largely unknown. The objectives of this research were to characterize the natural enemy community in wheat fields and evaluate the role of different natural enemy foraging guilds (foliar-foraging versus ground-dwelling predators) in regulating cereal aphid population growth. We investigated these objectives during the spring and summer of 2012 and 2013 in four winter wheat fields on the Michigan State University campus farm in East Lansing, Michigan. We monitored and measured the impact of natural enemies by experimentally excluding or allowing their access to wheat plants infested with Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Hemiptera: Aphidae). Our results indicate that the natural enemy community in the wheat fields consisted mostly of foliar-foraging and ground-dwelling predators with relatively few parasitoids. In combination, these natural enemy groups were very effective at reducing cereal aphid populations. We also investigated the role of each natural enemy foraging guild (foliar-foraging versus ground-dwelling predators) independently. Overall, our results suggest that, in combination, natural enemies can almost completely halt early-season aphid population increase. Independently, ground-dwelling predators were more effective at suppressing cereal aphid populations than foliar-foraging predators under the conditions we studied. Our results differ from studies in Europe and the US Great Plains where foliar foraging predators and parasitoids are frequently more important cereal aphid natural enemies. PMID:25473951

Seasonal regulation of condensed tannin consumption by free-ranging goats in a semi-arid savanna

PubMed Central

Heitkӧnig, Ignas M. A.; Scogings, Peter F.; Hattas, Dawood; Dziba, Luthando E.; Prins, Herbert H. T.; de Boer, Willem F.

2018-01-01

Although condensed tannins (CTs) are known to reduce forage intake by mammalian herbivores in controlled experiments, few studies have tested these effects in the field. Thus the role of CTs on foraging ecology of free-ranging herbivores is inadequately understood. To investigate the effects of CTs under natural savanna conditions, we pre-dosed groups of goats with polyethylene glycol (PEG, a CT-neutralising chemical), CT powder or water before observing their foraging behaviour. While accounting for the effects of season and time of the day, we tested the hypothesis that herbivores forage in ways that reduce the intake rate (g DM per minute) of CTs. We expected pre-dosing goats with CTs to reduce CT intake rates by (1) consuming diets low in CTs, (2) reducing bite rates, (3) increasing the number of foraging bouts, or (4) reducing the length of foraging bouts. Lastly, (5) expected CT to have no influence the number of dietary forage species. In both wet and dry seasons, pre-dosing goats with CTs resulted in lower CT consumption rates compared to PEG goats which seemed relieved from the stress associated with CT consumption. During dry season, the number of dietary forage species was similar across treatments, although goats that were dosed with PEG significantly increased this number in the wet season. Dosing goats with PEG increased the number and length of browsing bouts compared to goats from the other treatments. Pre-loading goats with PEG also tended to increase bite rates on browse forages, which contributed to increased consumption rates of CTs. Based on the behavioural adjustments made by goats in this study and within the constraints imposed by chemical complexity in savanna systems, we concluded that herbivores under natural conditions foraged in ways that minimised CTs consumption. More research should further elucidate the mechanism through which CTs regulated feeding behaviour. PMID:29293513

Distribution Patterns Predict Individual Specialization in the Diet of Dolphin Gulls

PubMed Central

Masello, Juan F.; Wikelski, Martin; Voigt, Christian C.; Quillfeldt, Petra

2013-01-01

Many animals show some degree of individual specialization in foraging strategies and diet. This has profound ecological and evolutionary implications. For example, populations containing diverse individual foraging strategies will respond in different ways to changes in the environment, thus affecting the capacity of the populations to adapt to environmental changes and to diversify. However, patterns of individual specialization have been examined in few species. Likewise it is usually unknown whether specialization is maintained over time, because examining the temporal scale at which specialization occurs can prove difficult in the field. In the present study, we analyzed individual specialization in foraging in Dolphin Gulls Leucophaeus scoresbii, a scavenger endemic to the southernmost coasts of South America. We used GPS position logging and stable isotope analyses (SIA) to investigate individual specialization in feeding strategies and their persistence over time. The analysis of GPS data indicated two major foraging strategies in Dolphin Gulls from New I. (Falkland Is./Islas Malvinas). Tagged individuals repeatedly attended either a site with mussel beds or seabird and seal colonies during 5 to 7 days of tracking. Females foraging at mussel beds were heavier than those foraging at seabird colonies. Nitrogen isotope ratios (δ15N) of Dolphin Gull blood cells clustered in two groups, showing that individuals were consistent in their preferred foraging strategies over a period of at least several weeks. The results of the SIA as well as the foraging patterns recorded revealed a high degree of specialization for particular feeding sites and diets by individual Dolphin Gulls. Individual differences in foraging behavior were not related to sex. Specialization in Dolphin Gulls may be favored by the advantages of learning and memorizing optimal feeding locations and behaviors. Specialized individuals may reduce search and handling time and thus, optimize their energy gain and/or minimize time spent foraging. PMID:23844073

Combined pesticide exposure severely affects individual- and colony-level traits in bees

PubMed Central

Gill, Richard J.; Ramos-Rodriguez, Oscar; Raine, Nigel E.

2012-01-01

Reported widespread declines of wild and managed insect pollinators have serious consequences for global ecosystem services and agricultural production1-3. Bees contribute around 80% of insect pollination, so it is imperative we understand and mitigate the causes of current declines4-6. Recent studies have implicated the role of pesticides as exposure to these chemicals has been associated with changes in bee behaviour7-11 and reductions in colony queen production12. However the key link between changes in individual behaviour and consequent impact at the colony level has not been shown. Social bee colonies depend on the collective performance of numerous individual workers. So whilst field-level pesticide concentrations can have a subtle/sublethal effect at the individual level8, it is not known whether bee societies can buffer such effects or if it results in a severe cumulative effect at the colony level. Furthermore, widespread agricultural intensification means bees are exposed to numerous pesticides when foraging13-15, yet the possible combinatorial effects of pesticide exposure have rarely been investigated16,17. Here we show that chronic exposure of bumblebees to two pesticides (neonicotinoid and pyrethroid) at concentrations that could approximate field-level exposure impairs natural foraging behaviour and increases worker mortality leading to significant reductions in brood development and colony success. We found worker foraging performance, particularly pollen collecting efficiency, was significantly reduced with observed knock-on effects for forager recruitment, worker losses and overall worker productivity. Moreover, we provide evidence that combinatorial exposure to pesticides increases the propensity of colonies to fail. PMID:23086150

Relationship between level of forage intake, blood flow and oxygen consumption by splanchnic tissues of sheep fed a tropical grass forage.

PubMed

Hentz, F; Kozloski, G V; Zeni, D; Brun, M V; Stefanello, S

2017-02-01

Four Polwarth castrated male sheep (42 ± 4.4 kg live weight (LW) surgically implanted with chronic indwelling catheters into the mesenteric, portal and hepatic veins, housed in metabolism cages and offered Cynodon sp. hay at rates (g of dry matter (DM)/kg LW) of 7, 14, 21 or ad libitum, were used in a 4 × 4 Latin square experiment to evaluate the effect of the level of forage intake on blood flow and oxygen consumption by the portal-drained viscera (PDV), liver and total splanchnic tissues (ST). The portal blood flow and the oxygen consumption by PDV linearly increased at increased organic matter (OM) intake. No effect of level of OM intake was obtained for the hepatic artery blood flow and oxygen consumption by liver. As a consequence, the level of OM intake only tended to directly affect hepatic blood flow and oxygen consumption by total ST. Oxygen consumption was linearly and positively related to blood flow across PDV, liver and total ST. The heat production by PDV and total ST, as proportion of metabolizable energy (ME) intake, decreased curvilinearly at increased ME intake. In conclusion, the oxygen consumption by PDV, but not by liver, was directly related to the level of forage intake by sheep. Moreover, when ingested at levels below maintenance, most of ME was spent as heat produced by ST. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Forage and weather influence day versus nighttime cow behavior and calf weaning weights on rangeland

USDA-ARS?s Scientific Manuscript database

We determined the effects of two forage allowance levels (LOW vs. HIGH) and weather conditions on day- and nighttime movement patterns of young rangeland-raised cows. We also investigated whether calf weaning weights (WW, n = 42) were significantly related to their dams' post-calving movement patter...

76 FR 23891 - Pyrasulfotole; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

... regulation establishes or revises tolerances for residues of pyrasulfotole in or on grain sorghum, grass, and...); sorghum, forage at 1.2 ppm; sorghum, stover at 0.35 ppm; grass, hay at 2.5 ppm; and grass, forage at 10... levels for sorghum, grass; and livestock commodities. The reasons for these changes are explained in Unit...

Ultra-High Foraging Rates of Harbor Porpoises Make Them Vulnerable to Anthropogenic Disturbance.

PubMed

Wisniewska, Danuta Maria; Johnson, Mark; Teilmann, Jonas; Rojano-Doñate, Laia; Shearer, Jeanne; Sveegaard, Signe; Miller, Lee A; Siebert, Ursula; Madsen, Peter Teglberg

2016-06-06

The question of how individuals acquire and allocate resources to maximize fitness is central in evolutionary ecology. Basic information on prey selection, search effort, and capture rates are critical for understanding a predator's role in its ecosystem and for predicting its response to natural and anthropogenic disturbance. Yet, for most marine species, foraging interactions cannot be observed directly. The high costs of thermoregulation in water require that small marine mammals have elevated energy intakes compared to similar-sized terrestrial mammals [1]. The combination of high food requirements and their position at the apex of most marine food webs may make small marine mammals particularly vulnerable to changes within the ecosystem [2-4], but the lack of detailed information about their foraging behavior often precludes an informed conservation effort. Here, we use high-resolution movement and prey echo recording tags on five wild harbor porpoises to examine foraging interactions in one of the most metabolically challenged cetacean species. We report that porpoises forage nearly continuously day and night, attempting to capture up to 550 small (3-10 cm) fish prey per hour with a remarkable prey capture success rate of >90%. Porpoises therefore target fish that are smaller than those of commercial interest, but must forage almost continually to meet their metabolic demands with such small prey, leaving little margin for compensation. Thus, for these "aquatic shrews," even a moderate level of anthropogenic disturbance in the busy shallow waters they share with humans may have severe fitness consequences at individual and population levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extreme precipitation variability, forage quality and large herbivore diet selection in arid environments

USGS Publications Warehouse

Cain, James W.; Gedir, Jay V.; Marshal, Jason P.; Krausman, Paul R.; Allen, Jamison D.; Duff, Glenn C.; Jansen, Brian; Morgart, John R.

2017-01-01

Nutritional ecology forms the interface between environmental variability and large herbivore behaviour, life history characteristics, and population dynamics. Forage conditions in arid and semi-arid regions are driven by unpredictable spatial and temporal patterns in rainfall. Diet selection by herbivores should be directed towards overcoming the most pressing nutritional limitation (i.e. energy, protein [nitrogen, N], moisture) within the constraints imposed by temporal and spatial variability in forage conditions. We investigated the influence of precipitation-induced shifts in forage nutritional quality and subsequent large herbivore responses across widely varying precipitation conditions in an arid environment. Specifically, we assessed seasonal changes in diet breadth and forage selection of adult female desert bighorn sheep Ovis canadensis mexicana in relation to potential nutritional limitations in forage N, moisture and energy content (as proxied by dry matter digestibility, DMD). Succulents were consistently high in moisture but low in N and grasses were low in N and moisture until the wet period. Nitrogen and moisture content of shrubs and forbs varied among seasons and climatic periods, whereas trees had consistently high N and moderate moisture levels. Shrubs, trees and succulents composed most of the seasonal sheep diets but had little variation in DMD. Across all seasons during drought and during summer with average precipitation, forages selected by sheep were higher in N and moisture than that of available forage. Differences in DMD between sheep diets and available forage were minor. Diet breadth was lowest during drought and increased with precipitation, reflecting a reliance on few key forage species during drought. Overall, forage selection was more strongly associated with N and moisture content than energy content. Our study demonstrates that unlike north-temperate ungulates which are generally reported to be energy-limited, N and moisture may be more nutritionally limiting for desert ungulates than digestible energy.

Dynamic oceanography determines fine scale foraging behavior of Masked Boobies in the Gulf of Mexico

PubMed Central

Harrison, Autumn-Lynn; Vallarino, Adriana; Gerard, Patrick D.; Jodice, Patrick G. R.

2017-01-01

During breeding, foraging marine birds are under biological, geographic, and temporal constraints. These contraints require foraging birds to efficiently process environmental cues derived from physical habitat features that occur at nested spatial scales. Mesoscale oceanography in particular may change rapidly within and between breeding seasons, and findings from well-studied systems that relate oceanography to seabird foraging may transfer poorly to regions with substantially different oceanographic conditions. Our objective was to examine foraging behavior of a pan-tropical seabird, the Masked Booby (Sula dactylatra), in the understudied Caribbean province, a moderately productive region driven by highly dynamic currents and fronts. We tracked 135 individuals with GPS units during May 2013, November 2013, and December 2014 at a regionally important breeding colony in the southern Gulf of Mexico. We measured foraging behavior using characteristics of foraging trips and used area restricted search as a proxy for foraging events. Among individual attributes, nest stage contributed to differences in foraging behavior whereas sex did not. Birds searched for prey at nested hierarchical scales ranging from 200 m—35 km. Large-scale coastal and shelf-slope fronts shifted position between sampling periods and overlapped geographically with overall foraging locations. At small scales (at the prey patch level), the specific relationship between environmental variables and foraging behavior was highly variable among individuals but general patterns emerged. Sea surface height anomaly and velocity of water were the strongest predictors of area restricted search behavior in random forest models, a finding that is consistent with the characterization of the Gulf of Mexico as an energetic system strongly influenced by currents and eddies. Our data may be combined with tracking efforts in the Caribbean province and across tropical regions to advance understanding of seabird sensing of the environment and serve as a baseline for anthropogenic based threats such as development, pollution, and commercial fisheries. PMID:28575078