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Sample records for ant workers food

  1. Food webs in the litter: effects of food and nest addition on ant communities in coffee agroecosystems and forest.

    PubMed

    Murnen, Cody J; Gonthier, David J; Philpott, Stacy M

    2013-08-01

    Community assembly is driven by multiple factors, including resource availability and habitat requirements. Litter nesting ants respond to food and nest site availability, and adding food and nests may increase ant species richness and abundance. However, litter decomposers share food resources with ants, and increasing food availability may speed decomposition processes, eliminating twigs and seeds in which litter ants nest. We manipulated ant food and nest resources in three habitat types (forest, high-shade coffee, and low-shade coffee) to determine ant community responses after 1 and 2 mo. We examined changes in numbers of ant species, colonies, workers, brood, colony growth rate, and ant species composition. Habitat type strongly affected ant communities, influencing ant species richness, numbers of colonies and workers, and ant species composition. However, food addition and nest addition did not affect these community characteristics. Colony growth rate did not differ with food addition but was greater in forest and low-shade coffee compared with high-shade coffee. Habitat differences in colony growth may be because of presence of an aggressive species (Wasmannia auropunctata Roger) in high-shade coffee plots or naturally low arthropod densities during a time when ant colonization was low. Thus, in coffee landscapes, habitat type impacts litter nesting ant community structure, composition, and colony growth rate; however, food and nest addition had small impacts.

  2. Food Service Worker.

    ERIC Educational Resources Information Center

    Barker, Ellen; And Others

    This curriculum guide provides instructional materials designed to prepare students for entry-level jobs such as dietetic aide or food service worker in a health care facility. It serves as the basic core of the occupationally sequenced Dietetic Support Personnel Training Program. Five sections and 13 instructional units are included. Each unit of…

  3. Food Service Worker.

    ERIC Educational Resources Information Center

    Barker, Ellen; And Others

    This curriculum guide provides instructional materials designed to prepare students for entry-level jobs such as dietetic aide or food service worker in a health care facility. It serves as the basic core of the occupationally sequenced Dietetic Support Personnel Training Program. Five sections and 13 instructional units are included. Each unit of…

  4. Sugary food robbing in ants: a case of temporal cleptobiosis.

    PubMed

    Richard, Freddie-Jeanne; Dejean, Alain; Lachaud, Jean-Paul

    2004-05-01

    This study reports new information on interactions between Ectatomma tuberculatum (Ponerinae) and Crematogaster limata parabiotica (Myrmicinae). Workers of these sympatric arboreal ant species forage on the same pioneer trees. Diurnally, Ectatomma preyed on Crematogaster workers that avoided overt aggression by respecting a 'safe distance'. At night, Crematogaster initiated raids within the Ectatomma nests that they apparently left with their abdomen empty, then remained near the nest entrances where they successfully intercepted 75.2% of the returning Ectatomma foragers (N = 322). Certain intercepted workers rapidly resumed their return trip. Others (39.1%) were stopped, explored and licked during a long time by the Crematogaster. Most of them were carrying between their mandibles a droplet of liquid food that was stolen. This relationship, that appears to be a typical case of interspecific cleptobiosis, whose expression varies during the daytime, demonstrates for the first time sugary-food robbing, instead of prey robbing, in ants.

  5. Young fire ant workers feign death and survive aggressive neighbors

    NASA Astrophysics Data System (ADS)

    Cassill, Deby L.; Vo, Kim; Becker, Brandie

    2008-07-01

    Feigning death is a method of self-defense employed among a wide range of prey species when threatened by predator species. This paper reports on death-feigning behavior by the fire ant, Solenopsis invicta, during intraspecific aggression among neighboring fire ant workers. Days-old workers responded to aggression by death feigning, weeks-old workers responded by fleeing and months-old workers responded by fighting back. By feigning death, days-old workers were four times more likely to survive aggression than older workers. From a proximate perspective, retaliation by young workers against aggressive older workers is certain to fail. With their relatively soft exoskeleton, young workers would be prone to injury and death and unable to execute an effective attack of biting or stinging older workers with harder exoskeletons. From an ultimate perspective, death feigning allows young workers to survive and contribute to brood care and colony growth, both of which are essential to queen survival and fitness.

  6. Young fire ant workers feign death and survive aggressive neighbors.

    PubMed

    Cassill, Deby L; Vo, Kim; Becker, Brandie

    2008-07-01

    Feigning death is a method of self-defense employed among a wide range of prey species when threatened by predator species. This paper reports on death-feigning behavior by the fire ant, Solenopsis invicta, during intraspecific aggression among neighboring fire ant workers. Days-old workers responded to aggression by death feigning, weeks-old workers responded by fleeing and months-old workers responded by fighting back. By feigning death, days-old workers were four times more likely to survive aggression than older workers. From a proximate perspective, retaliation by young workers against aggressive older workers is certain to fail. With their relatively soft exoskeleton, young workers would be prone to injury and death and unable to execute an effective attack of biting or stinging older workers with harder exoskeletons. From an ultimate perspective, death feigning allows young workers to survive and contribute to brood care and colony growth, both of which are essential to queen survival and fitness.

  7. Reactions by army ant workers to nestmates having had contact with sympatric ant species.

    PubMed

    Dejean, Alain; Corbara, Bruno

    2014-11-01

    It was recently shown that Pheidole megacephala colonies (an invasive species originating from Africa) counterattack when raided by the army ant, Eciton burchellii. The subsequent contact permits Pheidole cuticular compounds (that constitute the "colony odour") to be transferred onto the raiding Eciton, which are then not recognised by their colony-mates and killed. Using a simple method for transferring cuticular compounds, we tested if this phenomenon occurs for Neotropical ants. Eciton workers rubbed with ants from four sympatric species were released among their colony-mates. Individuals rubbed with Solenopsis saevissima or Camponotus blandus workers were attacked, but not those rubbed with Atta sexdens, Pheidole fallax or with colony-mates (control lot). So, the chemicals of certain sympatric ant species, but not others, trigger intra-colonial aggressiveness in Eciton. We conclude that prey-ant chemicals might have played a role in the evolution of army ant predatory behaviour, likely influencing prey specialization in certain cases.

  8. Random walk models of worker sorting in ant colonies.

    PubMed

    Sendova-Franks, Ana B; Van Lent, Jan

    2002-07-21

    Sorting can be an important mechanism for the transfer of information from one level of biological organization to another. Here we study the algorithm underlying worker sorting in Leptothorax ant colonies. Worker sorting is related to task allocation and therefore to the adaptive advantages associated with an efficient system for the division of labour in ant colonies. We considered four spatially explicit individual-based models founded on two-dimensional correlated random walk. Our aim was to establish whether sorting at the level of the worker population could occur with minimal assumptions about the behavioural algorithm of individual workers. The behaviour of an individual worker in the models could be summarized by the rule "move if you can, turn always". We assume that the turning angle of a worker is individually specific and negatively dependent on the magnitude of an internal parameter micro which could be regarded as a measure of individual experience or task specialization. All four models attained a level of worker sortedness that was compatible with results from experiments onLeptothorax ant colonies. We found that the presence of a sorting pivot, such as the nest wall or an attraction force towards the centre of the worker population, was crucial for sorting. We make a distinction between such pivots and templates and discuss the biological implications of their difference.

  9. Worker senescence and the sociobiology of aging in ants

    PubMed Central

    Giraldo, Ysabel Milton; Traniello, James F. A.

    2014-01-01

    Senescence, the decline in physiological and behavioral function with increasing age, has been the focus of significant theoretical and empirical research in a broad array of animal taxa. Preeminent among invertebrate social models of aging are ants, a diverse and ecologically dominant clade of eusocial insects characterized by reproductive and sterile phenotypes. In this review, we critically examine selection for worker lifespan in ants and discuss the relationship between functional senescence, longevity, task performance, and colony fitness. We did not find strong or consistent support for the hypothesis that demographic senescence in ants is programmed, or its corollary prediction that workers that do not experience extrinsic mortality die at an age approximating their lifespan in nature. We present seven hypotheses concerning how selection could favor extended worker lifespan through its positive relationship to colony size and predict that large colony size, under some conditions, should confer multiple and significant fitness advantages. Fitness benefits derived from long worker lifespan could be mediated by increased resource acquisition, efficient division of labor, accuracy of collective decision-making, enhanced allomaternal care and colony defense, lower infection risk, and decreased energetic costs of workforce maintenance. We suggest future avenues of research to examine the evolution of worker lifespan and its relationship to colony fitness, and conclude that an innovative fusion of sociobiology, senescence theory, and mechanistic studies of aging can improve our understanding of the adaptive nature of worker lifespan in ants. PMID:25530660

  10. Interspecific and temporal variation of ant species within Acacia drepanolobium ant domatia, a staple food of patas monkeys (Erythrocebus patas) in Laikipia, Kenya.

    PubMed

    Isbell, Lynne A; Young, Truman P

    2007-12-01

    The ants that live in the swollen thorns (domatia) of Acacia drepanolobium are staple foods for patas monkeys (Erythrocebus patas). To obtain a better understanding of these insects as resources for patas monkeys, we sampled the contents of 1,051 swollen thorns (ant domatia) over a 22-month period from December 1999 to September 2001, in Laikipia, Kenya. First, we confirmed that of the four species of ants that live on A. drepanolobium, Crematogaster sjostedti, the competitively dominant ant in this system, does not rear significant brood in the swollen thorns and is therefore not a major food item of patas monkeys. Second, across the other three species that do use swollen thorns for rearing their brood, C. nigriceps, C. mimosae, and Tetraponera penzigi, the number of worker ants per swollen thorn increased with increasing competitive dominance. Third, although there was considerable month-to-month variation in the number of workers, immatures, and especially alates (winged reproductives) within species, there was less variation across species because ant production was asynchronous. Variation in domatia contents was poorly related to rainfall for each of the three species. Finally, distal thorns held more alates and fewer workers than interior thorns, and branches higher off the ground held more alates and more workers than lower branches. For the numerically dominant C. mimosae, higher branches held significantly more immature ants than did lower branches. Ants are reliable food resources for patas monkeys, and are probably more reliable than many plant resources in this highly seasonal environment. We estimate that patas monkeys may get as much as a third of their daily caloric needs from these ants year-round. As ants and other insects are widely consumed by primates, we suggest that greater consideration be given to species differences in animal food choices and that further studies be conducted to examine the degree to which ants influence energy intake and

  11. Identification of an ant queen pheromone regulating worker sterility

    PubMed Central

    Holman, Luke; Jørgensen, Charlotte G.; Nielsen, John; d'Ettorre, Patrizia

    2010-01-01

    The selective forces that shape and maintain eusocial societies are an enduring puzzle in evolutionary biology. Ordinarily sterile workers can usually reproduce given the right conditions, so the factors regulating reproductive division of labour may provide insight into why eusociality has persisted over evolutionary time. Queen-produced pheromones that affect worker reproduction have been implicated in diverse taxa, including ants, termites, wasps and possibly mole rats, but to date have only been definitively identified in the honeybee. Using the black garden ant Lasius niger, we isolate the first sterility-regulating ant queen pheromone. The pheromone is a cuticular hydrocarbon that comprises the majority of the chemical profile of queens and their eggs, and also affects worker behaviour, by reducing aggression towards objects bearing the pheromone. We further show that the pheromone elicits a strong response in worker antennae and that its production by queens is selectively reduced following an immune challenge. These results suggest that the pheromone has a central role in colony organization and support the hypothesis that worker sterility represents altruistic self-restraint in response to an honest quality signal. PMID:20591861

  12. Summer and fall ants have different physiological responses to food macronutrient content.

    PubMed

    Cook, Steven C; Eubanks, Micky D; Gold, Roger E; Behmer, Spencer T

    2016-04-01

    Seasonally, long-lived animals exhibit changes in behavior and physiology in response to shifts in environmental conditions, including food abundance and nutritional quality. Ants are long-lived arthropods that, at the colony level, experience such seasonal shifts in their food resources. Previously we reported summer- and fall-collected ants practiced distinct food collection behavior and nutrient intake regulation strategies in response to variable food protein and carbohydrate content, despite being reared in the lab under identical environmental conditions and dietary regimes. Seasonally distinct responses were observed for both no-choice and choice dietary experiments. Using data from these same experiments, our objective here is to examine colony and individual-level physiological traits, colony mortality and growth, food processing, and worker lipid mass, and how these traits change in response to variable food protein-carbohydrate content. For both experiments we found that seasonality per se exerted strong effects on colony and individual level traits. Colonies collected in the summer maintained total worker mass despite high mortality. In contrast, colonies collected in the fall lived longer, and accumulated lipids, including when reared on protein-biased diets. Food macronutrient content had mainly transient effects on physiological responses. Extremes in food carbohydrate content however, elicited a compensatory response in summer worker ants, which processed more protein-biased foods and contained elevated lipid levels. Our study, combined with our previously published work, strongly suggests that underlying physiological phenotypes driving behaviors of summer and fall ants are likely fixed seasonally, and change circannually.

  13. 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.

  14. Foraging arena size and structural complexity affect the dynamics of food distribution in ant colonies.

    PubMed

    Buczkowski, Grzegorz; VanWeelden, Matthew

    2010-12-01

    Food acquisition by ant colonies is a complex process that starts with acquiring food at the source (i.e., foraging) and culminates with food exchange in or around the nest (i.e., feeding). While ant foraging behavior is relatively well understood, the process of food distribution has received little attention, largely because of the lack of methodology that allows for accurate monitoring of food flow. In this study, we used the odorous house ant, Tapinoma sessile (Say) to investigate the effect of foraging arena size and structural complexity on the rate and the extent of spread of liquid carbohydrate food (sucrose solution) throughout a colony. To track the movement of food, we used protein marking and double-antibody sandwich enzyme-linked immunosorbent assay, DAS-ELISA. Variation in arena size, in conjunction with different colony sizes, allowed us to test the effect of different worker densities on food distribution. Results demonstrate that both arena size and colony size have a significant effect on the spread of the food and the number of workers receiving food decreased as arena size and colony size increased. When colony size was kept constant and arena size increased, the percentage of workers testing positive for the marker decreased, most likely because of fewer trophallactic interactions resulting from lower worker density. When arena size was kept constant and colony size increased, the percentage of workers testing positive decreased. Nonrandom (clustered) worker dispersion and a limited supply of food may have contributed to this result. Overall, results suggest that food distribution is more complete is smaller colonies regardless of the size of the foraging arena and that colony size, rather than worker density, is the primary factor affecting food distribution. The structural complexity of foraging arenas ranged from simple, two-dimensional space (empty arenas) to complex, three-dimensional space (arenas filled with mulch). The structural

  15. Feeding and Stocking Up: Radio-Labelled Food Reveals Exchange Patterns in Ants

    PubMed Central

    Buffin, Aurélie; Denis, Damien; Van Simaeys, Gaetan; Goldman, Serge; Deneubourg, Jean-Louis

    2009-01-01

    Food sharing is vital for a large number of species, either solitary or social, and is of particular importance within highly integrated societies, such as in colonial organisms and in social insects. Nevertheless, the mechanisms that govern the distribution of food inside a complex organizational system remain unknown. Using scintigraphy, a method developed for medical imaging, we were able to describe the dynamics of food-flow inside an ant colony. We monitored the sharing process of a radio-labelled sucrose solution inside a nest of Formica fusca. Our results show that, from the very first load that enters the nest, food present within the colony acts as negative feedback to entering food. After one hour of the experiments, 70% of the final harvest has already entered the nest. The total foraged quantity is almost four times smaller than the expected storage capacity. A finer study of the spatial distribution of food shows that although all ants have been fed rapidly (within 30 minutes), a small area representing on average 8% of the radioactive surface holds more than 25% of the stored food. Even in rather homogeneous nests, we observed a strong concentration of food in few workers. Examining the position of these workers inside the nest, we found heavily loaded ants in the centre of the aggregate. The position of the centre of this high-intensity radioactive surface remained stable for the three consecutive hours of the experiments. We demonstrate that the colony simultaneously managed to rapidly feed all workers (200 ants fed within 30 minutes) and build up food stocks to prevent food shortage, something that occurs rather often in changing environments. Though we expected the colony to forage to its maximum capacity, the flow of food entering the colony is finely tuned to the colony's needs. Indeed the food-flow decreases proportionally to the food that has already been harvested, liberating the work-force for other tasks. PMID:19536275

  16. Size and shape in the evolution of ant worker morphology.

    PubMed

    Pie, Marcio R; Tschá, Marcel K

    2013-01-01

    Morphological evolution in ants has been traditionally thought as being strongly influenced by selection for colony ergonomic efficiency. Although many studies have focused on the evolution of social characteristics in ants, little is known about the evolution of worker morphology at a macroevolutionary scale. In this study, we investigate the tempo and mode of the evolution of worker morphology, focusing on changes in size and shape. Our datasets included a large sample of species from different ant genera, as well as variation within the hyperdiverse genus Pheidole, for a total of 1650 measurements. The rate of size evolution was at least five times faster than the rate of shape evolution. The fit of alternative models of morphological evolution indicated statistically significant phylogenetic signal in both size and shape and in all datasets. Finally, tests of rate heterogeneity in phenotypic evolution among lineages identified several shifts in rates of evolution in both datasets, although the timing of shifts in size and shape was usually not concordant.

  17. Size and shape in the evolution of ant worker morphology

    PubMed Central

    Tschá, Marcel K.

    2013-01-01

    Morphological evolution in ants has been traditionally thought as being strongly influenced by selection for colony ergonomic efficiency. Although many studies have focused on the evolution of social characteristics in ants, little is known about the evolution of worker morphology at a macroevolutionary scale. In this study, we investigate the tempo and mode of the evolution of worker morphology, focusing on changes in size and shape. Our datasets included a large sample of species from different ant genera, as well as variation within the hyperdiverse genus Pheidole, for a total of 1650 measurements. The rate of size evolution was at least five times faster than the rate of shape evolution. The fit of alternative models of morphological evolution indicated statistically significant phylogenetic signal in both size and shape and in all datasets. Finally, tests of rate heterogeneity in phenotypic evolution among lineages identified several shifts in rates of evolution in both datasets, although the timing of shifts in size and shape was usually not concordant. PMID:24255818

  18. Food collection and response to pheromones in an ant species exposed to electromagnetic radiation.

    PubMed

    Cammaerts, Marie-Claire; Rachidi, Zoheir; Bellens, François; De Doncker, Philippe

    2013-09-01

    We used the ant species Myrmica sabuleti as a model to study the impact of electromagnetic waves on social insects' response to their pheromones and their food collection. We quantified M. sabuleti workers' response to their trail, area marking and alarm pheromone under normal conditions. Then, we quantified the same responses while under the influence of electromagnetic waves. Under such an influence, ants followed trails for only short distances, no longer arrived at marked areas and no longer orientated themselves to a source of alarm pheromone. Also when exposed to electromagnetic waves, ants became unable to return to their nest and recruit congeners; therefore, the number of ants collecting food increases only slightly and slowly. After 180 h of exposure, their colonies deteriorated. Electromagnetic radiation obviously affects social insects' behavior and physiology.

  19. Indirect effects of alternative food resources in an ant-plant interaction.

    PubMed

    Boulay, R; Fedriani, J M; Manzaneda, A J; Cerdá, X

    2005-06-01

    The seeds of many plant species present a food body that is consumed by animal dispersers. In theory, if the animals are polyphagous, the availability of alternative food resource other than the diaspore itself may influence its dispersal and survival. We used the myrmecochore Helleborus foetidus L. (Ranunculaceae), the seeds of which are attached to a lipid-rich elaiosome that is attractive to ants, as a model system to investigate (1) whether alternative foods that are present along with the plant affect ant foraging behavior and diaspore removal and (2) whether food availability in an ant nest affects seed predation and germination. In a field experiment, artificial diaspore depots were offered together with either sugar, insect corpses, seed, or no food (control). Contrary to the prediction that ants would rather concentrate their foraging effort on the highly rewarding alternative foods only, many workers, attracted by the sugar, switched to the hellebore diaspores, which significantly enhanced removal rate. Results obtained in the laboratory further indicated that the larvae of Aphaenogaster iberica (a major seed disperser) predated more on the H. foetidus embryos when no alternative food was available. This, in turn, slightly reduced seed germination. Overall, these results shed light, for the first time, on the potential indirect effects of alternative resources on the fate of diaspores adapted for ant dispersal.

  20. Global energy gradients and size in colonial organisms: worker mass and worker number in ant colonies.

    PubMed

    Kaspari, Michael

    2005-04-05

    Body mass shapes processes from cell metabolism to community dynamics. Little is known, however, about how the average body mass of individuals varies among ecological communities. Ants alter colony mass by independently changing worker mass and/or worker number. In a survey of 49 ecosystems from tundra to tropical rainforest, average worker mass and worker number were uncorrelated (r(s) = 0.2, P > 0.14) and varied 100-fold. Data supported the hypothesis that higher mean monthly temperatures, T, reduce worker mass by increasing metabolic costs during worker development. In contrast, worker number was unimodal over a 1,000-fold gradient of net primary productivity (NPP, g of carbon per m2 per yr), a measure of organic carbon available to consumers. At the lowest levels of NPP colonies appeared to be carbon-limited; above 60 g of carbon per m2 per yr average worker number decreased to a global low. This decline in worker number with increasing NPP supports the hypothesis that abundant carbon ameliorates the Achilles heel of small taxa in competition with large taxa: their relatively high metabolic demands. Higher predation rates in resource-rich environments may also play a role in limiting worker number. In all, about half the global variation in worker mass and number was accounted for by gradients of NPP and T. Changes in global temperature and rainfall may thus mold gradients of ectotherm size, with consequences for the structure and function of the ecosystems.

  1. Global network structure of dominance hierarchy of ant workers

    PubMed Central

    Shimoji, Hiroyuki; Abe, Masato S.; Tsuji, Kazuki; Masuda, Naoki

    2014-01-01

    Dominance hierarchy among animals is widespread in various species and believed to serve to regulate resource allocation within an animal group. Unlike small groups, however, detection and quantification of linear hierarchy in large groups of animals are a difficult task. Here, we analyse aggression-based dominance hierarchies formed by worker ants in Diacamma sp. as large directed networks. We show that the observed dominance networks are perfect or approximate directed acyclic graphs, which are consistent with perfect linear hierarchy. The observed networks are also sparse and random but significantly different from networks generated through thinning of the perfect linear tournament (i.e. all individuals are linearly ranked and dominance relationship exists between every pair of individuals). These results pertain to global structure of the networks, which contrasts with the previous studies inspecting frequencies of different types of triads. In addition, the distribution of the out-degree (i.e. number of workers that the focal worker attacks), not in-degree (i.e. number of workers that attack the focal worker), of each observed network is right-skewed. Those having excessively large out-degrees are located near the top, but not the top, of the hierarchy. We also discuss evolutionary implications of the discovered properties of dominance networks. PMID:25100318

  2. Ant workers exhibit specialization and memory during raft formation

    NASA Astrophysics Data System (ADS)

    Avril, Amaury; Purcell, Jessica; Chapuisat, Michel

    2016-06-01

    By working together, social insects achieve tasks that are beyond the reach of single individuals. A striking example of collective behaviour is self-assembly, a process in which individuals link their bodies together to form structures such as chains, ladders, walls or rafts. To get insight into how individual behavioural variation affects the formation of self-assemblages, we investigated the presence of task specialization and the role of past experience in the construction of ant rafts. We subjected groups of Formica selysi workers to two consecutive floods and monitored the position of individuals in rafts. Workers showed specialization in their positions when rafting, with the same individuals consistently occupying the top, middle, base or side position in the raft. The presence of brood modified workers' position and raft shape. Surprisingly, workers' experience in the first rafting trial with brood influenced their behaviour and raft shape in the subsequent trial without brood. Overall, this study sheds light on the importance of workers' specialization and memory in the formation of self-assemblages.

  3. Global network structure of dominance hierarchy of ant workers.

    PubMed

    Shimoji, Hiroyuki; Abe, Masato S; Tsuji, Kazuki; Masuda, Naoki

    2014-10-06

    Dominance hierarchy among animals is widespread in various species and believed to serve to regulate resource allocation within an animal group. Unlike small groups, however, detection and quantification of linear hierarchy in large groups of animals are a difficult task. Here, we analyse aggression-based dominance hierarchies formed by worker ants in Diacamma sp. as large directed networks. We show that the observed dominance networks are perfect or approximate directed acyclic graphs, which are consistent with perfect linear hierarchy. The observed networks are also sparse and random but significantly different from networks generated through thinning of the perfect linear tournament (i.e. all individuals are linearly ranked and dominance relationship exists between every pair of individuals). These results pertain to global structure of the networks, which contrasts with the previous studies inspecting frequencies of different types of triads. In addition, the distribution of the out-degree (i.e. number of workers that the focal worker attacks), not in-degree (i.e. number of workers that attack the focal worker), of each observed network is right-skewed. Those having excessively large out-degrees are located near the top, but not the top, of the hierarchy. We also discuss evolutionary implications of the discovered properties of dominance networks.

  4. Ant workers exhibit specialization and memory during raft formation.

    PubMed

    Avril, Amaury; Purcell, Jessica; Chapuisat, Michel

    2016-06-01

    By working together, social insects achieve tasks that are beyond the reach of single individuals. A striking example of collective behaviour is self-assembly, a process in which individuals link their bodies together to form structures such as chains, ladders, walls or rafts. To get insight into how individual behavioural variation affects the formation of self-assemblages, we investigated the presence of task specialization and the role of past experience in the construction of ant rafts. We subjected groups of Formica selysi workers to two consecutive floods and monitored the position of individuals in rafts. Workers showed specialization in their positions when rafting, with the same individuals consistently occupying the top, middle, base or side position in the raft. The presence of brood modified workers' position and raft shape. Surprisingly, workers' experience in the first rafting trial with brood influenced their behaviour and raft shape in the subsequent trial without brood. Overall, this study sheds light on the importance of workers' specialization and memory in the formation of self-assemblages.

  5. Wasps robbing food from ants: a frequent behavior?

    NASA Astrophysics Data System (ADS)

    Lapierre, Louis; Hespenheide, Henry; Dejean, Alain

    2007-12-01

    Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes. (1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more common than previously thought.

  6. Worker caste determination in the army ant Eciton burchellii.

    PubMed

    Jaffé, Rodolfo; Kronauer, Daniel J C; Kraus, F Bernhard; Boomsma, Jacobus J; Moritz, Robin F A

    2007-10-22

    Elaborate division of labour has contributed significantly to the ecological success of social insects. Division of labour is achieved either by behavioural task specialization or by morphological specialization of colony members. In physical caste systems, the diet and rearing environment of developing larvae is known to determine the phenotype of adult individuals, but recent studies have shown that genetic components also contribute to the determination of worker caste. One of the most extreme cases of worker caste differentiation occurs in the army ant genus Eciton, where queens mate with many males and colonies are therefore composed of numerous full-sister subfamilies. This high intracolonial genetic diversity, in combination with the extreme caste polymorphism, provides an excellent test system for studying the extent to which caste determination is genetically controlled. Here we show that genetic effects contribute significantly to worker caste fate in Eciton burchellii. We conclude that the combination of polyandry and genetic variation for caste determination may have facilitated the evolution of worker caste diversity in some lineages of social insects.

  7. Fitness costs of worker specialization for ant societies.

    PubMed

    Jongepier, Evelien; Foitzik, Susanne

    2016-01-13

    Division of labour is of fundamental importance for the success of societies, yet little is known about how individual specialization affects the fitness of the group as a whole. While specialized workers may be more efficient in the tasks they perform than generalists, they may also lack the flexibility to respond to rapid shifts in task needs. Such rigidity could impose fitness costs when societies face dynamic and unpredictable events, such as an attack by socially parasitic slavemakers. Here, we experimentally assess the colony-level fitness consequences of behavioural specialization in Temnothorax longispinosus ants that are attacked by the slavemaker ant T. americanus. We manipulated the social organization of 102 T. longispinosus colonies, based on the behavioural responses of all 3842 workers. We find that strict specialization is disadvantageous for a colony's annual reproduction and growth during slave raids. These fitness costs may favour generalist strategies in dynamic environments, as we also demonstrate that societies exposed to slavemakers in the field show a lower degree of specialization than those originating from slavemaker-free populations. Our findings provide an explanation for the ubiquity of generalists and highlight their importance for the flexibility and functional robustness of entire societies.

  8. Fitness costs of worker specialization for ant societies

    PubMed Central

    Jongepier, Evelien; Foitzik, Susanne

    2016-01-01

    Division of labour is of fundamental importance for the success of societies, yet little is known about how individual specialization affects the fitness of the group as a whole. While specialized workers may be more efficient in the tasks they perform than generalists, they may also lack the flexibility to respond to rapid shifts in task needs. Such rigidity could impose fitness costs when societies face dynamic and unpredictable events, such as an attack by socially parasitic slavemakers. Here, we experimentally assess the colony-level fitness consequences of behavioural specialization in Temnothorax longispinosus ants that are attacked by the slavemaker ant T. americanus. We manipulated the social organization of 102 T. longispinosus colonies, based on the behavioural responses of all 3842 workers. We find that strict specialization is disadvantageous for a colony's annual reproduction and growth during slave raids. These fitness costs may favour generalist strategies in dynamic environments, as we also demonstrate that societies exposed to slavemakers in the field show a lower degree of specialization than those originating from slavemaker-free populations. Our findings provide an explanation for the ubiquity of generalists and highlight their importance for the flexibility and functional robustness of entire societies. PMID:26763706

  9. Intraguild interactions between spiders and ants and top-down control in a grassland food web.

    PubMed

    Sanders, Dirk; Platner, Christian

    2007-01-01

    In most terrestrial ecosystems ants (Formicidae) as eusocial insects and spiders (Araneida) as solitary trappers and hunters are key predators. To study the role of predation by these generalist predators in a dry grassland, we manipulated densities of ants and spiders (natural and low density) in a two-factorial field experiment using fenced plots. The experiment revealed strong intraguild interactions between ants and spiders. Higher densities of ants negatively affected the abundance and biomass of web-building spiders. The density of Linyphiidae was threefold higher in plots without ant colonies. The abundance of Formica cunicularia workers was significantly higher in spider-removal plots. Also, population size of springtails (Collembola) was negatively affected by the presence of wandering spiders. Ants reduced the density of Lepidoptera larvae. In contrast, the abundance of coccids (Ortheziidae) was positively correlated with densities of ants. To gain a better understanding of the position of spiders, ants and other dominant invertebrate groups in the studied food web and important trophic links, we used a stable isotope analysis ((15)N and (13)C). Adult wandering spiders were more enriched in (15)N relative to (14)N than juveniles, indicating a shift to predatory prey groups. Juvenile wandering and web-building spiders showed delta(15)N ratios just one trophic level above those of Collembola, and they had similar delta(13)C values, indicating that Collembola are an important prey group for ground living spiders. The effects of spiders demonstrated in the field experiment support this result. We conclude that the food resource of spiders in our study system is largely based on the detrital food web and that their effects on herbivores are weak. The effects of ants are not clear-cut and include predation as well as mutualism with herbivores. Within this diverse predator guild, intraguild interactions are important structuring forces.

  10. Chemical profiles of mated and virgin queens, egg-laying intermorphs and workers of the ant Crematogaster smithi.

    PubMed

    Oettler, Jan; Schmitt, Thomas; Herzner, Gudrun; Heinze, Jürgen

    2008-04-01

    Many colonies of the North American ant Crematogaster smithi contain a "third female caste" in addition to queens and workers. These "intermorphs" are morphological intermediate of queens and workers and have well-developed ovaries but lack a spermatheca for the storage of sperm. They are specialised for laying large numbers of unfertilised, viable eggs, most of which serve as food for larvae and adults, though a few may eventually develop into males. Based on the assumption that cuticular hydrocarbons (CHCs) in social insects honestly signal the reproductive status of an individual we investigated the CHC of mated mature queens, virgin queens, intermorphs and workers. We expected intermorphs to show chemical profiles intermediate between those of mated queens and non-reproductive workers. A discriminant analysis of the chemical profiles reliably separated queens, virgin queens, and workers, but failed to distinguish between queens and intermorphs even though workers were apparently capable of doing so.

  11. Larval regulation of worker reproduction in the polydomous ant Novomessor cockerelli.

    PubMed

    Ebie, Jessica D; Hölldobler, Bert; Liebig, Jürgen

    2015-12-01

    Although workers in many ant species are capable of producing their own offspring, they generally rear the queen's offspring instead. There are various mechanisms that regulate worker reproduction including inhibitory effects of ant brood. Colonies of the ant Novomessor cockerelli are monogynous and polydomous resulting in a large portion of nest workers being physically isolated from the queen for extended periods of time. Some workers experimentally isolated from the queen in laboratory nests lay viable eggs, which develop into males. We investigate the mechanism that regulates worker fertility in subnests separated from the queen by giving queenless worker groups queen-produced larvae, queen-produced eggs, or no brood. Our findings show that larvae delay the time to worker egg-laying, but eggs have no effect. Larval inhibition is a likely mechanism that contributes to the regulation of worker reproduction in N. cockerellli because larvae are easily transported to subnests that do not contain a queen.

  12. Larval regulation of worker reproduction in the polydomous ant Novomessor cockerelli

    NASA Astrophysics Data System (ADS)

    Ebie, Jessica D.; Hölldobler, Bert; Liebig, Jürgen

    2015-12-01

    Although workers in many ant species are capable of producing their own offspring, they generally rear the queen's offspring instead. There are various mechanisms that regulate worker reproduction including inhibitory effects of ant brood. Colonies of the ant Novomessor cockerelli are monogynous and polydomous resulting in a large portion of nest workers being physically isolated from the queen for extended periods of time. Some workers experimentally isolated from the queen in laboratory nests lay viable eggs, which develop into males. We investigate the mechanism that regulates worker fertility in subnests separated from the queen by giving queenless worker groups queen-produced larvae, queen-produced eggs, or no brood. Our findings show that larvae delay the time to worker egg-laying, but eggs have no effect. Larval inhibition is a likely mechanism that contributes to the regulation of worker reproduction in N. cockerellli because larvae are easily transported to subnests that do not contain a queen.

  13. Allometry of Workers of the Fire Ant, Solenopsis invicta

    PubMed Central

    Tschinkel, Walter R.; Mikheyev, Alexander S.; Storz, Shonna R.

    2003-01-01

    The relationship between worker body size and the shape of their body parts was explored in the polymorphic ant, Solenopsis invicta. The data consisted of 20 measurements of body parts as well as sums of some of these measurements. Size-free shape variables were created by taking the ratios of relevant measures. After log-transformation, these ratios were regressed against the logarithm of total body length, or against the log of the size of the parent part. Slopes of zero indicated that shape did not change with size, and non-zero slopes signaled a size-related change of shape. Across the range of worker sizes, the head length retained a constant proportion to body length, but relative headwidth increased such that head shape changed from a barrel-profile to a somewhat heart-shaped profile. Antennae became relatively smaller, with the club contributing more to this decline than the other parts. The alinotum became relatively shorter and higher (more humped), and the gaster increased in both relative width and length, and therefore in volume. All three pairs of legs were isometric to body length. The component parts of the legs, with one exception, were isometric to their own total leg length. The body of S. invicta is therefore dominated by mostly modest allometries, giving large workers a somewhat different shape than small ones. None of these size-shape relationships was different for different colonies. The functional meaning of these shape changes is unknown, but that does not stop us from speculating. Abbreviation: HL head length BL body length HW1 width across the eyes HW2 width above the eyes HW3 width below the eyes PMID:15841219

  14. Establishing food site vectors in desert ants.

    PubMed

    Bolek, Siegfried; Wittlinger, Matthias; Wolf, Harald

    2012-02-15

    When returning to the site of a successful previous forage, where does one search for the goodies? Should one rely on experience from the previous homebound journey, or should one consider the outbound journey as well, or even exclusively? Desert ants are particularly well suited for pursuing this question because of their primary reliance on path integration in open and featureless desert habitats. Path integration has been studied particularly with regard to homing after lengthy foraging trips. The ants also use path integration to return to plentiful feeding sites, but what is memorised for revisiting the feeder remains controversial. Here, we demonstrate that desert ants consider, and indeed linearly average, both outbound and inbound travel for their return to a familiar feeder. This may be interpreted as a strategy to reduce navigation errors.

  15. Control of body size of Lasius niger ant sexuals--worker interests, genes and environment.

    PubMed

    Fjerdingstad, Else J

    2005-09-01

    In most animals, the survival and reproductive success of males and females is linked to their size. The ability of individuals to control environmental influences on size will therefore have consequences for their fitness. In eusocial insects, individual males and reproductive females do not have to forage for themselves or control their local environment. Instead, they are reared by nonreproductive siblings (workers) inside colonies. Workers should benefit from controlling the size of sexuals because these sexuals are usually the only means for workers to transmit their genes to future generations. Nevertheless, considerable intraspecific variation exists around mean sexual size in social hymenopterans, even in species with monomorphic sexuals. This variation could result from genetic influences on sexual size, for instance sexuals may be selected to not agree to worker interests, or be due to strong, unpredictable environmental conditions constraining the efforts of workers to control sexual size. In a study that is the first of its kind I investigated genetic and environmental components of sexual body size variation in the ant Lasius niger, examining sexuals from wild colonies with one or several fathers (paternity levels established through microsatellite DNA offspring analysis). Evidence was found for a genetic component of size (broad-sense heritability of up to 42%) but strong common-colony effects (among-colony variation in food availability or in worker capacities to restrain sexual selfishness) also increased the size differences among colonies. Workers thus seem to only have partial-control over sexual size, but may be doing the best of a bad job.

  16. Olfactory memory established during trophallaxis affects food search behaviour in ants.

    PubMed

    Provecho, Yael; Josens, Roxana

    2009-10-01

    Camponotus mus ants can associate sucrose and odour at the source during successive foraging cycles and use this memory to locate the nectar in the absence of other cues. These ants perform conspicuous trophallactic behaviour during recruitment while foraging for nectar. In this work, we studied whether Camponotus mus ants are able to establish this odour-sucrose association in the social context of trophallaxis and we evaluated this memory in another context previously experienced by the ant, as a nectar source. After a single trophallaxis of a scented solution, the receiver ant was tested in a Y-maze without any reward, where two scents were presented: in one arm, the solution scent and in the other, a new scent. Ants consistently chose the arm with the solution scent and stayed longer therein. Trophallaxis duration had no effect on the arm choice or with the time spent in each arm. Workers are able to associate an odour (conditioned stimulus) with the sucrose (unconditioned stimulus) they receive through a social interaction and use this memory as choice criteria during food searching.

  17. Internest food sharing within wood ant colonies: resource redistribution behavior in a complex system

    PubMed Central

    Robinson, Elva J.H.

    2016-01-01

    Resource sharing is an important cooperative behavior in many animals. Sharing resources is particularly important in social insect societies, as division of labor often results in most individuals including, importantly, the reproductives, relying on other members of the colony to provide resources. Sharing resources between individuals is therefore fundamental to the success of social insects. Resource sharing is complicated if a colony inhabits several spatially separated nests, a nesting strategy common in many ant species. Resources must be shared not only between individuals in a single nest but also between nests. We investigated the behaviors facilitating resource redistribution between nests in a dispersed-nesting population of wood ant Formica lugubris. We marked ants, in the field, as they transported resources along the trails between nests of a colony, to investigate how the behavior of individual workers relates to colony-level resource exchange. We found that workers from a particular nest “forage” to other nests in the colony, treating them as food sources. Workers treating other nests as food sources means that simple, pre-existing foraging behaviors are used to move resources through a distributed system. It may be that this simple behavioral mechanism facilitates the evolution of this complex life-history strategy. PMID:27004016

  18. Study on the Repellency of Callicarpenal and Intermedeol against Workers of Imported Fire Ants

    USDA-ARS?s Scientific Manuscript database

    Repellency of callicarpenal and intermedeol, two terpenoids isolated from American beautyberry and Japanese beautyberry, were tested against workers of red imported fire ants, Solenopsis invicta Buren, black imported fire ants, Solenopsis richteri Forel, and a hybrid of these two species using diggi...

  19. Degeneration patterns of the worker spermatheca during morphogenesis in ants (Hymenoptera: Formicidae).

    PubMed

    Gotoh, Ayako; Billen, Johan; Hashim, Rosli; Ito, Fuminori

    2016-01-01

    Reproductive division of labor is one of the crucial features in social insects, however, the developmental mechanisms leading to modifications in the reproductive apparatus of workers are still not very clear. Ants show a remarkable diversity in the morphological specialization of the worker's reproductive apparatus, that allows to distinguish four types, type 1: workers that have ovaries and a functional spermatheca, and that reproduce like queens, type 2: workers have ovaries and a vestigial spermatheca, type 3: workers have ovaries but no spermatheca, and type 4: workers lost both ovaries and spermatheca. We investigated morphogenesis of the worker spermatheca in 28 ant species by histological examination. In workers of type 1, the morphogenesis of the spermatheca is very similar to that in ant queens. In type 2, the spermathecal disc also differentiates, however, the development is interrupted and remains vestigial. In types 3 and 4, the absence of the spermatheca in the adult phase is caused by a degeneration after initial formation of the spermathecal disc or by a complete lack of the spermathecal discs. The timing of these interruption and degeneration events varies among species. The species exhibiting an earlier interrupting point of spermatheca formation in workers have a larger queen-worker dimorphism, that seems to be independent from ant phylogeny. © 2016 Wiley Periodicals, Inc.

  20. Plant-ants use symbiotic fungi as a food source: new insight into the nutritional ecology of ant-plant interactions.

    PubMed

    Blatrix, Rumsaïs; Djiéto-Lordon, Champlain; Mondolot, Laurence; La Fisca, Philippe; Voglmayr, Hermann; McKey, Doyle

    2012-10-07

    Usually studied as pairwise interactions, mutualisms often involve networks of interacting species. Numerous tropical arboreal ants are specialist inhabitants of myrmecophytes (plants bearing domatia, i.e. hollow structures specialized to host ants) and are thought to rely almost exclusively on resources derived from the host plant. Recent studies, following up on century-old reports, have shown that fungi of the ascomycete order Chaetothyriales live in symbiosis with plant-ants within domatia. We tested the hypothesis that ants use domatia-inhabiting fungi as food in three ant-plant symbioses: Petalomyrmex phylax/Leonardoxa africana, Tetraponera aethiops/Barteria fistulosa and Pseudomyrmex penetrator/Tachigali sp. Labelling domatia fungal patches in the field with either a fluorescent dye or (15)N showed that larvae ingested domatia fungi. Furthermore, when the natural fungal patch was replaced with a piece of a (15)N-labelled pure culture of either of two Chaetothyriales strains isolated from T. aethiops colonies, these fungi were also consumed. These two fungi often co-occur in the same ant colony. Interestingly, T. aethiops workers and larvae ingested preferentially one of the two strains. Our results add a new piece in the puzzle of the nutritional ecology of plant-ants.

  1. Nutritional and food insecurity of construction workers.

    PubMed

    de Lima Brasil, Evi Clayton; de Araújo, Lindemberg Medeiros; de Toledo Vianna, Rodrigo Pinheiro

    2016-06-27

    Construction workers have intensive contact with their workplace and are possibly susceptible to Nutritional and Food Insecurity. This paper assessed the Food Security status, diet and anthropometric measures of workers in the Construction Industry living in the city of João Pessoa, PB. This cross-sectional study included 59 workers housed at construction sites. The workers were given the Brazilian Scale for Measuring Food Insecurity and Nutrition, had anthropometric measures taken and completed the Diet Quality Index, comparing their eating at the construction site and at home. Statistical analyses described the mean, standard deviation, frequency and Pearson correlations. Food Insecurity was reported by 71.2% of the workers, and 69.5% were overweight. The mean values of the Healthy Eating Index suggested that the workers' diets were in need of modification. There were statistically significant inverse associations among the Healthy Eating Index and Body Mass Index, waist circumference, percentage of total fat and cholesterol. Values obtained using the Scale showed Food Insecurity coupled with high excess weight and dietary inadequacies, revealing that these workers are at risk for health problems.

  2. Food Service Worker. Supplemental Individualized Student Modules.

    ERIC Educational Resources Information Center

    Hasty, Liswa E.; Bridwell, Terry B.

    Developed to supplement the food service worker modules published in 1977, this handbook provides fourteen additional individualized student modules. The topics included are as follow: (1) personal grooming; (2) safe handling of food and eating utensils; (3) setting up tables; (4) handling customers; (5) menus; (6) taking and placing the order;…

  3. Food Service Worker. Supplemental Individualized Student Modules.

    ERIC Educational Resources Information Center

    Hasty, Liswa E.; Bridwell, Terry B.

    Developed to supplement the food service worker modules published in 1977, this handbook provides fourteen additional individualized student modules. The topics included are as follow: (1) personal grooming; (2) safe handling of food and eating utensils; (3) setting up tables; (4) handling customers; (5) menus; (6) taking and placing the order;…

  4. Possible evidence for shift work schedules in the media workers of the ant species Camponotus compressus.

    PubMed

    Sharma, Vijay Kumar; Lone, Shahnaz Rahman; Mathew, Deepa; Goel, Anubhuthi; Chandrashekaran, M K

    2004-03-01

    The locomotor activity rhythm of the media workers of the ant species Camponotus compressus was monitored under constant conditions of the laboratory to understand the role of circadian clocks in social organization. The locomotor activity rhythm of most ants entrained to a 24h light/dark (12:12h; LD) cycle and free-ran under constant darkness (DD) with circadian periodicities. Under entrained conditions about 75% of media workers displayed nocturnal activity patterns, and the rest showed diurnal activity patterns. In free-running conditions these ants displayed three types of activity patterns (turn-around). The free-running period (tau) of the locomotor activity rhythm of some ants (10 out of 21) showed period lengthening, and those of a few (6 out of 21) showed period shortening, whereas the locomotor activity rhythm of the rest of the ants (5 out of 21) underwent large phase shifts. Interestingly, the pre-turn-around tau of those ants that showed nocturnal activity patterns during earlier LD entrainment was shorter than 24 h, which became greater than 24 h after 6-9 days of free-run in DD. On the other hand, the pre-turn-around tau of those ants, which exhibited diurnal patterns during earlier LD entrainment, was greater than 24 h, which became shorter than 24 h after 6-9 days of free-run in DD. The patterns of activity under LD cycles and the turn-around of activity patterns in DD regime suggest that these ants are shift workers in their respective colonies, and they probably use their circadian clocks for this purpose. Circadian plasticity thus appears to be a general strategy of the media workers of the ant species C. compressus to cope with the challenges arising due to their roles in the colony constantly exposed to a fluctuating environment.

  5. Effect of temperature and social environment on worker size in the ant Temnothorax nylanderi.

    PubMed

    Molet, Mathieu; Péronnet, Romain; Couette, Sébastien; Canovas, Christophe; Doums, Claudie

    2017-07-01

    Warm temperatures decrease insect developmental time and body size. Social life could buffer external environmental variations, especially in large social groups, either through behavioral regulation and compensation or through specific nest architecture. Mean worker size and distribution of worker sizes within colonies are important parameters affecting colony productivity as worker size is linked to division of labor in insect societies. In this paper, we investigate the effect of stressful warm temperatures and the role of social environment (colony size and size of nestmate workers) on the mean size and size variation of laboratory-born workers in the small European ant Temnothorax nylanderi. To do so, we reared field-collected colonies under medium or warm temperature treatments after having marked the field-born workers and removed the brood except for 30 first instar larvae. Warm temperature resulted in the production of fewer workers and a higher adult mortality, confirming that this regime was stressful for the ants. T. nylanderi ants followed the temperature size rule observed in insects, with a decreased developmental time and mean size under warm condition. Social environment appeared to play an important role as we observed that (i) larger colonies buffered the effect of temperature better than smaller ones (ii) colonies with larger workers produced larger workers whatever the rearing temperature and (iii) the coefficient of variation of worker size was similar in the field and under medium laboratory temperature. This suggests that worker size variation is not primarily due to seasonal environmental fluctuations in the field. Finally, we observed a higher coefficient of variation of worker size under warm temperature. We propose that this results from a disruption of social regulation, i.e. the control of nestmate workers over developing larvae and adult worker size, under stressful conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Regulation of host workers' oviposition by the social parasite ant Polyergus samurai.

    PubMed

    Tsuneoka, Yousuke

    2014-07-01

    Polyergus samurai, an obligatory social parasite ant, lacks the ability to perform usual colony tasks. It depends completely on host Formica japonica workers. In the mixed colony, arrhenotokous reproduction by host workers must be detrimental to the parasites. This study, conducted under artificial rearing conditions, investigated the behavioral influence by P. samurai worker on the production of host workers' male eggs. Host workers started laying eggs when the P. samurai queen was removed, but most eggs were destroyed by P. samurai workers. In a queenless condition, P. samurai workers showed frequent intraspecific dominance interactions, but few interspecific ones. After a short while the P. samurai worker started laying eggs, the F. japonica worker stopped laying eggs. The ovary had no mature oocyte. These results suggest that both the P. samurai queen and dominant workers can inhibit host workers' oviposition. A mesh experiment revealed that the dominant P. samurai workers were able to inhibit host workers' oviposition without contacts. The dominant workers and queens of P. samurai frequently received grooming and trophallaxis from host workers just as a host queen does, suggesting that the parasites secreted similar products to those of the host queen to inhibit the host workers' oviposition.

  7. Fast food in ant communities: how competing species find resources.

    PubMed

    Pearce-Duvet, Jessica M C; Moyano, Martin; Adler, Frederick R; Feener, Donald H

    2011-09-01

    An understanding of foraging behavior is crucial to understanding higher level community dynamics; in particular, there is a lack of information about how different species discover food resources. We examined the effect of forager number and forager discovery capacity on food discovery in two disparate temperate ant communities, located in Texas and Arizona. We defined forager discovery capacity as the per capita rate of resource discovery, or how quickly individual ants arrived at resources. In general, resources were discovered more quickly when more foragers were present; this was true both within communities, where species identity was ignored, as well as within species. This pattern suggests that resource discovery is a matter of random processes, with ants essentially bumping into resources at a rate mediated by their abundance. In contrast, species that were better discoverers, as defined by the proportion of resources discovered first, did not have higher numbers of mean foragers. Instead, both mean forager number and mean forager discovery capacity determined discovery success. The Texas species used both forager number and capacity, whereas the Arizona species used only forager capacity. There was a negative correlation between a species' prevalence in the environment and the discovery capacity of its foragers, suggesting that a given species cannot exploit both high numbers and high discovery capacity as a strategy. These results highlight that while forager number is crucial to determining time to discovery at the community level and within species, individual forager characteristics influence the outcome of exploitative competition in ant communities.

  8. Desert ants locate food by combining high sensitivity to food odors with extensive crosswind runs.

    PubMed

    Buehlmann, Cornelia; Graham, Paul; Hansson, Bill S; Knaden, Markus

    2014-05-05

    Desert ants feeding on dead arthropods forage for food items that are distributed unpredictably in space and time in the food-scarce terrain of the Saharan salt pans [1]. Scavengers of the genus Cataglyphis forage individually and do not lay pheromone trails [2]. They rely primarily on path integration [3] for navigation and, in addition, use visual [4] and olfactory cues [5-7]. While most studies have focused on the navigational mechanisms of ants targeting a familiar place like the nest or a learned feeding site, little is known about how ants locate food in their natural environment. Here we show that Cataglyphis fortis is highly sensitive to and attracted by food odors, especially the necromone linoleic acid, enabling them to locate tiny arthropods over several meters in distance. Furthermore, during the search for food, ants use extensive crosswind walks that increase the chances of localizing food plumes. By combining high sensitivity toward food odors with crosswind runs, the ants efficiently screen the desert for food and hence reduce the time spent foraging in their harsh desert environment.

  9. Small queens and big-headed workers in a monomorphic ponerine ant

    NASA Astrophysics Data System (ADS)

    Kikuchi, Tomonori; Miyazaki, Satoshi; Ohnishi, Hitoshi; Takahashi, Junichi; Nakajima, Yumiko; Tsuji, Kazuki

    2008-10-01

    Evolution of caste is a central issue in the biology of social insects. Comparative studies on their morphology so far suggest the following three patterns: (1) a positive correlation between queen worker size dimorphism and the divergence in reproductive ability between castes, (2) a negative correlation among workers between morphological diversity and reproductive ability, and (3) a positive correlation between queen worker body shape difference and the diversity in worker morphology. We conducted morphological comparisons between castes in Pachycondyla luteipes, workers of which are monomorphic and lack their reproductive ability. Although the size distribution broadly overlapped, mean head width, head length, and scape length were significantly different between queens and workers. Conversely, in eye length, petiole width, and Weber’s length, the size differences were reversed. The allometries (head length/head width, scape length/head width, and Weber’s length/head width) were also significantly different between queens and workers. Morphological examinations showed that the body shape was different between queens and workers, and the head part of workers was disproportionately larger than that of queens. This pattern of queen worker dimorphism is novel in ants with monomorphic workers and a clear exception to the last pattern. This study suggests that it is possible that the loss of individual-level selection, the lack of reproductive ability, influences morphological modification in ants.

  10. Case studies of violations of workers' freedom of association: food processing workers and contingent workers.

    PubMed

    2002-01-01

    As part of its report "Unfair Advantage: Workers' Freedom of Association in the United States under International Human Rights Standards," Human Rights Watch conducted a series of case studies in a dozen states, covering a variety of industries and employment sectors, analyzing the U.S. experience in the light of both national law and international human rights and labor rights norms. Presented here are the case studies of food processing workers and contingent workers.

  11. Being a Food Service Worker; Student Manual.

    ERIC Educational Resources Information Center

    Hospital Research and Educational Trust, Chicago, IL.

    Instructional materials for student use in training or retraining for the occupation of food service worker at the vocational high school or community college level were developed by professional consultants. They were tested in a nationwide on-the-job training program and revised according to instructor evaluation and consultant suggestions. A…

  12. Training the Food Service Worker; Instructor's Guide.

    ERIC Educational Resources Information Center

    Hospital Research and Educational Trust, Chicago, IL.

    Curriculum materials for instructor use in planning lessons to train or retrain food service workers at the vocational high school or community college level were developed by professional consultants. They were tested in a nation-wide on-the-job training program and revised according to instructor evaluation and consultant suggestions. A minimum…

  13. Being a Food Service Worker; Student Manual.

    ERIC Educational Resources Information Center

    Hospital Research and Educational Trust, Chicago, IL.

    Instructional materials for student use in training or retraining for the occupation of food service worker at the vocational high school or community college level were developed by professional consultants. They were tested in a nationwide on-the-job training program and revised according to instructor evaluation and consultant suggestions. A…

  14. Training the Food Service Worker; Instructor's Guide.

    ERIC Educational Resources Information Center

    Hospital Research and Educational Trust, Chicago, IL.

    Curriculum materials for instructor use in planning lessons to train or retrain food service workers at the vocational high school or community college level were developed by professional consultants. They were tested in a nation-wide on-the-job training program and revised according to instructor evaluation and consultant suggestions. A minimum…

  15. Molecular and social regulation of worker division of labour in fire ants.

    PubMed

    Manfredini, Fabio; Lucas, Christophe; Nicolas, Michael; Keller, Laurent; Shoemaker, Dewayne; Grozinger, Christina M

    2014-02-01

    Reproductive and worker division of labour (DOL) is a hallmark of social insect societies. Despite a long-standing interest in worker DOL, the molecular mechanisms regulating this process have only been investigated in detail in honey bees, and little is known about the regulatory mechanisms operating in other social insects. In the fire ant Solenopsis invicta, one of the most studied ant species, workers are permanently sterile and the tasks performed are modulated by the worker's internal state (age and size) and the outside environment (social environment), which potentially includes the effect of the queen presence through chemical communication via pheromones. However, the molecular mechanisms underpinning these processes are unknown. Using a whole-genome microarray platform, we characterized the molecular basis for worker DOL and we explored how a drastic change in the social environment (i.e. the sudden loss of the queen) affects global gene expression patterns of worker ants. We identified numerous genes differentially expressed between foraging and nonforaging workers in queenright colonies. With a few exceptions, these genes appear to be distinct from those involved in DOL in bees and wasps. Interestingly, after the queen was removed, foraging workers were no longer distinct from nonforaging workers at the transcriptomic level. Furthermore, few expression differences were detected between queenright and queenless workers when we did not consider the task performed. Thus, the social condition of the colony (queenless vs. queenright) appears to impact the molecular pathways underlying worker task performance, providing strong evidence for social regulation of DOL in S. invicta. Published 2013. This article is a U.S. Government work and is in the public domain in the U.S.A.

  16. Re-visiting of plentiful food sources and food search strategies in desert ants.

    PubMed

    Wolf, Harald; Wittlinger, Matthias; Bolek, Siegfried

    2012-01-01

    North African desert ants, Cataglyphis fortis, are established model organisms in animal navigation research. Cataglyphis re-visit plentiful feeding sites, but their decision to return to a feeder and the organization of food searches has been little studied. Here we provide a review of recent advances regarding this topic. At least two parameters determine the ants' assessment of site quality, namely, amount of food available and reliability of food encounter on subsequent visits. The amount of food appears to be judged by the concentration of items at the food uptake site. Initially the amount of food in a feeder dominates the foragers' decision to return, whereas learning about reliability takes precedence in the course of a few visits. The location of a worthwhile site is determined by the animals' path integration system. In particular, the distance of the feeding site is memorized as the arithmetic average of the distances covered during the previous outbound and homebound journeys. Feeding sites that are small and inconspicuous cannot be approached directly with sufficient certainty, due to inevitable inaccuracies of the path integrator. Instead, desert ants steer downwind of the goal to encounter the odor plume emanating from the food and they follow this plume to the feeder. The angle steered downwind reflects the animals' maximal navigation error and is adjusted according to experience. In summary, food searches of desert ants provide an unexpected wealth of features that may advance our understanding of search, navigation, and decision strategies. There are several aspects that warrant further scrutiny.

  17. Queen regulates biogenic amine level and nestmate recognition in workers of the fire ant, Solenopsis invicta

    NASA Astrophysics Data System (ADS)

    Vander Meer, Robert K.; Preston, Catherine A.; Hefetz, Abraham

    2008-12-01

    Nestmate recognition is a critical element in social insect organization, providing a means to maintain territoriality and close the colony to parasites and predators. Ants detect the colony chemical label via their antennae and respond to the label mismatch of an intruder with aggressive behavior. In the fire ant, Solenopsis invicta, worker ability to recognize conspecific nonnestmates decreases if the colony queen is removed, such that they do not recognize conspecific nonnestmates as different. Here, we tested the hypothesis that the presence of the colony queen influences the concentration of octopamine, a neuromodulator, in worker ants, which in turn has an effect on nestmate recognition acuity in workers. We demonstrate that queenless workers exhibit reduced brain octopamine levels and reduced discriminatory acuteness; however, feeding queenless workers octopamine restored both. Dopamine levels are influenced by honeybee queen pheromones; however, levels of this biogenic amine were unchanged in our experiments. This is the first demonstration of a link between the presence of the colony queen, a worker biogenic amine, and conspecific nestmate recognition, a powerful expression of colony cohesion and territoriality.

  18. Determination of the cost of worker reproduction via diminished life span in the ant Diacamma sp.

    PubMed

    Tsuji, Kazuki; Kikuta, Noritsugu; Kikuchi, Tomonori

    2012-05-01

    Workers of social Hymenoptera can usually produce male offspring, but rarely do so in the presence of a queen despite the potential individual fitness benefit. Various mechanisms have been hypothesized to regulate worker reproduction, including avoiding the colony-level cost of worker reproduction. However, firm quantitative evidence is lacking to support that hypothesis. Here, we accurately quantified this cost by studying an ant species (Diacamma sp.) in which worker reproduction is rare in the presence of the gamergate (the functional queen). A series of experiments to manipulate worker-gamergate contact revealed that short-term brood-production efficiency is not changed by the presence of worker reproduction. However, when workers reproduce, their average life span is reduced to between 74% and 88% of that in the absence of reproduction, indicating a long-term cost to the colony. In theory, this cost can explain the policing of worker reproduction under a queen-single mating system, but the cost does not appear to be high enough to stop worker reproduction. When contact with the gamergate is lost, it is only the nonreproductive workers whose life span was reduced; the reproductive workers lived as long as nonorphaned workers. We suggest that an increased workload can account for the reduction in life span better than a trade-off between reproduction and longevity.

  19. Ant-dependent food plant selection by the mistletoe butterfly Ogyris amaryllis (Lycaenidae).

    PubMed

    Atsatt, Peter R

    1981-02-01

    A quantitative study of the relationship between antoccupied mistletoes and oviposition by Ogyris amaryllis (Lycaenidae) revealed diet selection to be ant-dependent. Chemical toxins apparently prohibit the use of ant-occupied Lysiana plants. Nearly all of the 5106 censused eggs were laid on Amyema individuals with ants, independent of plant abundance or relative quality. On the average, only 32% of these nutritionally acceptable individuals were actually suitable for oviposition. The selection of Amyema maidenii with ants over nutritionally superior A. preissii without ants clearly identifies the secondary importance of food quality to O. amaryllis. Oviposition normally occurs after tactile stimulation by ants. Under experimental conditions without ants, females often laid clutches of 1-3 eggs, but significantly increased clutch size after contact with ants. Eggs laid in the presence of ants had lower parasitism rates than eggs laid away from ants.

  20. Effects of worker size on the dynamics of fire ant tunnel construction

    PubMed Central

    Gravish, Nick; Garcia, Mateo; Mazouchova, Nicole; Levy, Laura; Umbanhowar, Paul B.; Goodisman, Michael A. D.; Goldman, Daniel I.

    2012-01-01

    Social insects work together to complete tasks. However, different individuals within a colony may vary in task proficiency. We investigated if fire ant (Solenopsis invicta) worker body size influenced the ability to construct tunnels—a key component of subterranean nests. We monitored excavation by worker groups in a substrate of small wetted glass particles in quasi-two-dimensional arenas. Morphological and network features of the tunnel system were measured. Total tunnel area did not differ significantly between groups of large and small workers, although the tunnel area of control sized workers was significantly larger than that of large workers. Moreover, large workers created wider but shorter tunnels, with slower growth rate of tunnel number. However, edge–vertex scaling and degree distribution of the tunnel network were similar across all treatments. In all cases, the amount of excavated material was correlated with the number of active workers. Our study reveals that morphological features of excavated tunnels show modest variation when constructed by workers of varying sizes, but topological features associated with the tunnel network are conserved. These results suggest that important behavioural aspects of tunnel construction—and thus nest building—are similar among morphologically distinct members of fire ant societies. PMID:22915634

  1. Effects of worker size on the dynamics of fire ant tunnel construction.

    PubMed

    Gravish, Nick; Garcia, Mateo; Mazouchova, Nicole; Levy, Laura; Umbanhowar, Paul B; Goodisman, Michael A D; Goldman, Daniel I

    2012-12-07

    Social insects work together to complete tasks. However, different individuals within a colony may vary in task proficiency. We investigated if fire ant (Solenopsis invicta) worker body size influenced the ability to construct tunnels--a key component of subterranean nests. We monitored excavation by worker groups in a substrate of small wetted glass particles in quasi-two-dimensional arenas. Morphological and network features of the tunnel system were measured. Total tunnel area did not differ significantly between groups of large and small workers, although the tunnel area of control sized workers was significantly larger than that of large workers. Moreover, large workers created wider but shorter tunnels, with slower growth rate of tunnel number. However, edge-vertex scaling and degree distribution of the tunnel network were similar across all treatments. In all cases, the amount of excavated material was correlated with the number of active workers. Our study reveals that morphological features of excavated tunnels show modest variation when constructed by workers of varying sizes, but topological features associated with the tunnel network are conserved. These results suggest that important behavioural aspects of tunnel construction--and thus nest building--are similar among morphologically distinct members of fire ant societies.

  2. Degeneration of sperm reservoir and the loss of mating ability in worker ants.

    PubMed

    Gobin, Bruno; Ito, Fuminori; Billen, Johan; Peeters, Christian

    2008-11-01

    Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term storage of sperm. Such 'non-sexual' workers are restricted to laying unfertilized eggs that give rise to males, and they cannot compete with the queens for the production of female offspring. In sharp contrast, workers in 200-300 species from phylogenetically basal subfamilies can reproduce sexually ('gamergates') because they retain a functional spermatheca like the queens. Importantly, 'non-sexual' workers in closely related species have a vestigial spermatheca. In this study, we compared the reservoir epithelium of 'sexual' workers to that of congeneric queens and 'non-sexual' workers using 21 species of Amblyoponinae, Ponerinae and Ectatomminae. We show that a pronounced thickening of the epithelium near the opening of the sperm duct is strictly associated with sexual reproduction in both castes. This is unlike 'non-sexual' workers in which this epithelium is always very thin, with few organelles; but all other structures remain intact. We discuss this evolutionary degeneration of the spermatheca and how it relates to behavioural or physiological modifications linked to mating. Our results help understand the loss of sexual reproduction by ant workers, a critical step in the extreme specialization of their phenotype.

  3. Degeneration of sperm reservoir and the loss of mating ability in worker ants

    NASA Astrophysics Data System (ADS)

    Gobin, Bruno; Ito, Fuminori; Billen, Johan; Peeters, Christian

    2008-11-01

    Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term storage of sperm. Such ‘non-sexual’ workers are restricted to laying unfertilized eggs that give rise to males, and they cannot compete with the queens for the production of female offspring. In sharp contrast, workers in 200 300 species from phylogenetically basal subfamilies can reproduce sexually (‘gamergates’) because they retain a functional spermatheca like the queens. Importantly, ‘non-sexual’ workers in closely related species have a vestigial spermatheca. In this study, we compared the reservoir epithelium of ‘sexual’ workers to that of congeneric queens and ‘non-sexual’ workers using 21 species of Amblyoponinae, Ponerinae and Ectatomminae. We show that a pronounced thickening of the epithelium near the opening of the sperm duct is strictly associated with sexual reproduction in both castes. This is unlike ‘non-sexual’ workers in which this epithelium is always very thin, with few organelles; but all other structures remain intact. We discuss this evolutionary degeneration of the spermatheca and how it relates to behavioural or physiological modifications linked to mating. Our results help understand the loss of sexual reproduction by ant workers, a critical step in the extreme specialization of their phenotype.

  4. Survival of Atta sexdens workers on different food sources.

    PubMed

    Silva, Aline; Bacci, Maurício; Gomes de Siqueira, Célia; Correa Bueno, Odair; Pagnocca, Fernando Carlos; Aparecida Hebling, Maria José

    2003-04-01

    Leaf-cutting ants belonging to the tribe Attini are major herbivores and important agriculture pests in the neotropics, these ants being thought to feed on the sap which exudes from the plant material which they cut and also on the mycelium of a symbiotic fungus that grows on plant material inside their nests in what is called "the fungus garden". However, we have found that the survival of Atta sexdens worker ants on leaves, on mycelium of the ants' symbiotic fungus, Leucoagaricus gongylophorus, or on plant polysaccharides was the same as that of starved A. sexdens, while, conversely, significantly longer survival was achieved by ants fed on the fungus garden material or on some of the products (especially glucose) of the hydrolysis of plant polysaccharides. We found that the fungus garden contained glucose at a higher concentration than that found in leaves or fungal mycelium, and that this glucose was consumed by the ant to the extent that it was probably responsible for up to 50% of the nutritional needs of the workers. The fungus garden contained polysaccharide degrading enzymes (pectinase, amylase, xylanase and cellulase) in proportions similar to that observed in laboratory cultures of L. gongylophorus. It thus appears that A. sexdens workers obtain a significant part of their nutrients from plant polysaccharide hydrolysis products produced by the action of extracellular enzymes released by L. gongylophorus. In this paper we discuss the symbiotic nutrition strategy of A. sexdens workers and brood and the role played by plant polysaccharides in the nutrition of attine ants.

  5. The Old Ladies of the Seed Harvester ant Pogonomyrmex Rugosus: Foraging Performed by Two Groups of Workers.

    PubMed

    Oettler, Jan; Johnson, Robert A

    2009-05-01

    We examined temporal polyethism in Pogonomyrmex rugosus, predicting a pattern of decreasing age from foragers to nest maintenance workers to individuals that were recruited to harvest a temporary food source. Nest maintenance workers were younger than foragers, as indicated by their heavier mass and lower mandibular wear. In contrast, recruited foragers were similar in mass to foragers but they displayed higher mandibular wear, suggesting that they were at least as old as foragers. Longevity estimates for marked individuals of these two latter task groups showed mixed results. Higher mandibular wear of recruited foragers suggests that they did not follow the normal sequence for temporal polyethism, but rather that they functioned as seed-millers, which should more quickly abrade their dentition. This would be the first demonstration of specialist milling individuals in a monomorphic seed-harvester ant.

  6. Aggressions and size-related fecundity of queenless workers in the ant Cataglyphis cursor

    NASA Astrophysics Data System (ADS)

    Clémencet, Johanna; Rome, Quentin; Fédérici, Pierre; Doums, Claudie

    2008-02-01

    In social hymenoptera, the reproductive division of labor is often linked to differences in individual body size with the reproductive caste (the queen) being larger than the workers. Likewise, the reproductive potential may vary with size within the worker caste and could affect the evolution of worker size in social insects. Here, we tested the relationship between worker size and reproductive potential in the facultative parthenogenetic ant Cataglyphis cursor. Colonies are headed by a multiply mated queen, but workers can produce gynes (virgin queens) and workers by thelytokous parthenogenesis after the queen’s death. We observed the behaviour of workers ( n = 357) until the production of gynes (212 h over 3 months) in an orphaned colony (mated queen not present). The size of workers was measured, and their paternal lineage determined using six microsatellite markers, to control for an effect of patriline. Larger workers were more likely to reproduce and lay more eggs indicating that individual level selection could take place. However, paternal lineage had no effect on the reproductive potential and worker size. From the behavioural and genetic data, we also show for the first time in this species, evidence of aggressive interactions among workers and a potential for nepotism to occur in orphaned colonies, as the five gynes produced belonged to a single paternal lineage.

  7. Queen pheromones modulate DNA methyltransferase activity in bee and ant workers

    PubMed Central

    Holman, Luke; Trontti, Kalevi; Helanterä, Heikki

    2016-01-01

    DNA methylation is emerging as an important regulator of polyphenism in the social insects. Research has concentrated on differences in methylation between queens and workers, though we hypothesized that methylation is involved in mediating other flexible phenotypes, including pheromone-dependent changes in worker behaviour and physiology. Here, we find that exposure to queen pheromone affects the expression of two DNA methyltransferase genes in Apis mellifera honeybees and in two species of Lasius ants, but not in Bombus terrestris bumblebees. These results suggest that queen pheromones influence the worker methylome, pointing to a novel proximate mechanism for these key social signals. PMID:26814223

  8. Queen pheromones modulate DNA methyltransferase activity in bee and ant workers.

    PubMed

    Holman, Luke; Trontti, Kalevi; Helanterä, Heikki

    2016-01-01

    DNA methylation is emerging as an important regulator of polyphenism in the social insects. Research has concentrated on differences in methylation between queens and workers, though we hypothesized that methylation is involved in mediating other flexible phenotypes, including pheromone-dependent changes in worker behaviour and physiology. Here, we find that exposure to queen pheromone affects the expression of two DNA methyltransferase genes in Apis mellifera honeybees and in two species of Lasius ants, but not in Bombus terrestris bumblebees. These results suggest that queen pheromones influence the worker methylome, pointing to a novel proximate mechanism for these key social signals. © 2016 The Author(s).

  9. Hydrocarbon signals explain the pattern of worker and egg policing in the ant Aphaenogaster cockerelli.

    PubMed

    Smith, Adrian A; Hölldobler, Bert; Liebig, Jürgen

    2008-10-01

    In ant societies, worker reproduction is regulated through policing behaviors, such as physical aggression or egg eating. The information used by policing individuals is thought to be in blends of hydrocarbons present on the cuticle and the surface of eggs. These fertility signals have been studied in numerous genera. However, signaling patterns that emerge across distinct subfamilies of ants have yet to be explained. We investigated policing behavior and the chemical signaling upon which policing behaviors are informed in the ant Aphaenogaster cockerelli. We found that worker-produced eggs are not policed, and we showed that there is a lack of chemical signaling for effective egg policing to occur in this species. Furthermore, we identified the available signals that demarcate workers to be policed physically. We showed that in A. cockerelli, a species with derived social organization, workers produce fertility signals identical to the queen. This queen-like signaling may be due to workers maintaining a high level of ovarian activity, linked to trophic egg production, in the presence of the queen.

  10. Patterns of venom production and temporal polyethism in workers of Jerdon's jumping ant, Harpegnathos saltator.

    PubMed

    Haight, Kevin L

    2012-12-01

    Ants are chemical factories, and among their more noticeable products are their venoms. Though many studies have addressed the properties and activities of ant venoms, basic venom-related physiological questions, such as how venom production and replacement may vary with age, are rarely addressed. The answers to these questions are fundamental to understanding the physiological capabilities of these organisms, as well as the parameters within which potential optimization of their investment in venom production must take place. The only previous investigation into venom production in ants found it to be limited to early life in workers of the fire ant, Solenopsis invicta (Haight and Tschinkel, 2003). Because similar studies have not been conducted for comparison, it is unclear whether or not this is a common physiological pattern in ants. As a parsimonious way to address this question, and, more generally, to increase the currently scant information available regarding the venom-producing capabilities of ants, the longevity, temporal polyethism, age-related venom production, and age-related venom replacement capabilities of workers of Jerdon's jumping ant, Harpegnathos saltator were investigated. Longevity varied from 10 days to nearly 2 years, with a median lifespan of 206 days. Workers remained in the nest when young, transitioned to outside work (foraging) after 50 days of age, and reached a plateau in their tendency to be outside the nest at 74 days of age. They eclosed with empty venom sacs, filled them by about 57 days of age, and were able to replace venom at all three ages tested (though at a higher rate when aged 100 days than 30 and 206). So, venom-production ability is not limited to early life in H. saltator workers, and aspects of venom physiology and exploratory behavior appear to coincide in a manner likely to result in foraging efficiency benefits; venom sacs reach fullness around the age workers begin their foraging careers, and venom replacement

  11. Foraging energetics of a nectar-feeding ant: metabolic expenditure as a function of food-source profitability.

    PubMed

    Schilman, Pablo E; Roces, Flavio

    2006-10-01

    We examined the quantitative relationship between the energetic costs and benefits of nectar collection by nectar-feeding ants, Camponotus rufipes. In the laboratory, individual workers were trained to visit an artificial feeder that provided a sucrose solution of 1%, 5%, 10%, 30% or 50% at controlled flows, in a similar span range to those observed in natural nectar sources. We measured foraging times, nectar loads collected, and CO(2) production during actual feeding, as an indication of the energy expenditure for a single forager. Results show an increase in individual metabolic rates with increasing flow rate of sugar solution, but no dependence on sucrose concentration. This increase in metabolic expenditure does not depend on the crop load attained while feeding, as intuitively expected, and is therefore a result of an increased activity brought about by the food-source profitability experienced by the forager. The energy gained during collection of sugar solution is always higher than the energy spent by the ant. Even with a food source of lower quality than a natural source, the ants gain ca. tenfold of what they spend. Based on a simplified model, we calculated that foragers of C. rufipes could travel from 0.5 to 9 km with the energy gained in a single foraging trip only. These results suggest that decreasing foraging time is more important than increasing individual energetic efficiency when workers of the nectar-feeding ant C. rufipes decide to stop drinking and return to the nest with partial crop loads.

  12. Specialization in policing behaviour among workers in the ant Pachycondyla inversa.

    PubMed

    van Zweden, Jelle S; Fürst, Matthias A; Heinze, Jürgen; D'Ettorre, Patrizia

    2007-06-07

    Most animal societies are non-clonal and thus subject to conflicts. In social insects, conflict over male production can be resolved by worker policing, i.e. eating of worker-laid eggs (WLE) or aggression towards reproductive workers. All workers in a colony have an interest in policing behaviour being expressed, but there can be asymmetries among workers in performing the actual behaviour. Here, we show that workers of the ant Pachycondyla inversa specialize in policing behaviour. In two types of behavioural assays, workers developed their ovaries and laid eggs. In the first experiment, reproductive workers were introduced into queenright colonies. In the second experiment, WLE were introduced. By observing which individuals policed, we found that aggressive policing was highly skewed among workers that had opportunity to police, and that a similar tendency occurred in egg policing. None of the policing workers had active ovaries, so that policing did not incur a direct selfish benefit to the policer. This suggests that policing is subject to polyethism, just like other tasks in the colony. We discuss several hypotheses on the possible causes of this skew in policing tasks. This is the first non-primate example of specialization in policing tasks without direct selfish interests.

  13. Specialization in policing behaviour among workers in the ant Pachycondyla inversa

    PubMed Central

    van Zweden, Jelle S; Fürst, Matthias A; Heinze, Jürgen; D'Ettorre, Patrizia

    2007-01-01

    Most animal societies are non-clonal and thus subject to conflicts. In social insects, conflict over male production can be resolved by worker policing, i.e. eating of worker-laid eggs (WLE) or aggression towards reproductive workers. All workers in a colony have an interest in policing behaviour being expressed, but there can be asymmetries among workers in performing the actual behaviour. Here, we show that workers of the ant Pachycondyla inversa specialize in policing behaviour. In two types of behavioural assays, workers developed their ovaries and laid eggs. In the first experiment, reproductive workers were introduced into queenright colonies. In the second experiment, WLE were introduced. By observing which individuals policed, we found that aggressive policing was highly skewed among workers that had opportunity to police, and that a similar tendency occurred in egg policing. None of the policing workers had active ovaries, so that policing did not incur a direct selfish benefit to the policer. This suggests that policing is subject to polyethism, just like other tasks in the colony. We discuss several hypotheses on the possible causes of this skew in policing tasks. This is the first non-primate example of specialization in policing tasks without direct selfish interests. PMID:17389223

  14. SUPERVISED FOOD SERVICE WORKERS, A SUGGESTED TRAINING PROGRAM.

    ERIC Educational Resources Information Center

    Office of Education (DHEW), Washington, DC.

    RESOURCE MATERIAL FOR THE DEVELOPMENT OF TRAINING PROGRAMS FOR SUPERVISED FOOD SERVICE WORKERS WILL NEED TO BE ADAPTED TO THE NEEDS OF THE STUDENTS AND THE COMMUNITY. THE SUPERVISED FOOD SERVICE WORKER PREPARES AND SERVES FOOD, UNDER THE DIRECTION OF THE FOOD SERVICE SUPERVISOR, IN INSTITUTIONS SUCH AS HOSPITALS, NURSING HOMES, HOMES FOR THE AGED,…

  15. Acclimation effects on critical and lethal thermal limits of workers of the Argentine ant, Linepithema humile.

    PubMed

    Jumbam, Keafon R; Jackson, Susan; Terblanche, John S; McGeoch, Melodie A; Chown, Steven L

    2008-06-01

    For the Argentine ant Linepithema humile, bioclimatic models often predict narrower optimal temperature ranges than those suggested by behavioural and physiological studies. Although water balance characteristics of workers of this species have been thoroughly studied, gaps exist in current understanding of its thermal limits. We investigated critical thermal minima and maxima and upper and lower lethal limits following acclimation to four temperatures (15, 20, 25, 30 degrees C; 12L:12D photoperiod) in adult workers of the Argentine ant, L. humile, collected from Stellenbosch, South Africa. At an ecologically relevant rate of temperature change of 0.05 degrees Cmin(-1), CTMax varied between 38 and 40 degrees C, and CTMin varied between 0 and 0.8 degrees C. In both cases the response to acclimation was weak. A significant time by exposure temperature interaction was found for upper and lower lethal limits, with a more pronounced effect of acclimation at longer exposure durations. Upper lethal limits varied between 37 and 44 degrees C, whilst lower lethal limits varied between -4 and -10.5 degrees C, with an acclimation effect more pronounced for upper than lower lethal limits. A thermal envelope for workers of the Argentine ant is provided, demonstrating that upper thermal limits do likely contribute to distributional limits, but that lower lethal limits and limits to activity likely do not, or at least for workers who are not exposed simultaneously to the demands of load carriage and successful foraging behaviour.

  16. Queen execution increases relatedness among workers of the invasive Argentine ant, Linepithema humile.

    PubMed

    Inoue, Maki N; Ito, Fuminori; Goka, Koichi

    2015-09-01

    Polygyny in social insects can greatly reduce within-nest genetic relatedness. In polygynous ant species, potential rival queens in colonies with multiple queens are often executed by other queens, workers, or both. The Argentine ant, Linepithema humile, native to South America, forms a "supercolony" that is composed of a large number of nests and is considered to contribute to the ant's invasion success. Currently, four mutually antagonistic supercolonies are contiguously distributed within a small area of Japan. Here, we analyzed the genetic structure and relatedness within and among the four supercolonies using microsatellite markers to clarify how L. humile maintains its supercoloniality. The results of AMOVA and BASP, the F ST values, and the existence of several private alleles indicated that the L. humile population in the Kobe area had a characteristic genetic structure. Within a given supercolony, there was significant genetic differentiation (F ST) among workers collected in May and those collected in September. The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies. This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution. From the perspective of kin selection, workers collectively eliminate queens, thereby increasing their own inclusive fitness. Restricted gene flow among supercolonies, together with mating with sib and queen execution, could help to maintain the unique social structure of L. humile, the distribution of which is expanding worldwide.

  17. Higher expression of somatic repair genes in long-lived ant queens than workers

    PubMed Central

    Lucas, Eric R.; Privman, Eyal; Keller, Laurent

    2016-01-01

    Understanding why organisms senesce is a fundamental question in biology. One common explanation is that senescence results from an increase in macromolecular damage with age. The tremendous variation in lifespan between genetically identical queen and worker ants, ranging over an order of magnitude, provides a unique system to study how investment into processes of somatic maintenance and macromolecular repair influence lifespan. Here we use RNAseq to compare patterns of expression of genes involved in DNA and protein repair of age-matched queens and workers. There was no difference between queens and workers in 1-day-old individuals, but the level of expression of these genes increased with age and this up-regulation was greater in queens than in workers, resulting in significantly queen-biased expression in 2-month-old individuals in both legs and brains. Overall, these differences are consistent with the hypothesis that higher longevity is associated with increased investment into somatic repair. PMID:27617474

  18. Ant workers die young and colonies collapse when fed a high-protein diet

    PubMed Central

    Dussutour, A.; Simpson, S. J.

    2012-01-01

    A key determinant of the relationship between diet and longevity is the balance of protein and carbohydrate in the diet. Eating excess protein relative to carbohydrate shortens lifespan in solitary insects. Here, we investigated the link between high-protein diet and longevity, both at the level of individual ants and colonies in black garden ants, Lasius niger. We explored how lifespan was affected by the dietary protein-to-carbohydrate ratio and the duration of exposure to a high-protein diet. We show that (i) restriction to high-protein, low-carbohydrate diets decreased worker lifespan by up to 10-fold; (ii) reduction in lifespan on such diets was mainly due to elevated intake of protein rather than lack of carbohydrate; and (iii) only one day of exposure to a high-protein diet had dire consequences for workers and the colony, reducing population size by more than 20 per cent. PMID:22357267

  19. Winged queens replaced by reproductives smaller than workers in Mystrium ants

    NASA Astrophysics Data System (ADS)

    Molet, Mathieu; Peeters, Christian; Fisher, Brian L.

    2007-04-01

    In ants, winged queens that are specialized for independent colony foundation can be replaced by wingless reproductives better adapted for colony fission. We studied this shift in reproductive strategy by comparing two Mystrium species from Madagascar using morphometry, allometry and dissections. Mystrium rogeri has a single dealate queen in each colony with a larger thorax than workers and similar mandibles that allow these queens to hunt during non-claustral foundation. In contrast, Mystrium ‘red’ lacks winged queens and half of the female adults belong to a wingless ‘intermorph’ caste smaller and allometrically distinct from the workers. Intermorphs have functional ovaries and spermatheca while those of workers are degenerate. Intermorphs care for brood and a few mate and reproduce making them an all-purpose caste that takes charge of both work and reproduction. However, their mandibles are reduced and inappropriate for hunting centipedes, unlike the workers’ mandibles. This together with their small thorax disallow them to perform independent colony foundation, and colonies reproduce by fission. M. rogeri workers have mandibles polymorphic in size and shape, which allow for all tasks from brood care to hunting. In M. ‘red’, colonial investment in reproduction has shifted from producing expensive winged queens to more numerous helpers. M. ‘red’ intermorphs are the first case of reproductives smaller than workers in ants and illustrate their potential to diversify their caste system for better colonial economy.

  20. Colony fusion and worker reproduction after queen loss in army ants

    PubMed Central

    Kronauer, Daniel J. C.; Schöning, Caspar; d'Ettorre, Patrizia; Boomsma, Jacobus J.

    2010-01-01

    Theory predicts that altruism is only evolutionarily stable if it is preferentially directed towards relatives, so that any such behaviour towards seemingly unrelated individuals requires scrutiny. Queenless army ant colonies, which have anecdotally been reported to fuse with queenright foreign colonies, are such an enigmatic case. Here we combine experimental queen removal with population genetics and cuticular chemistry analyses to show that colonies of the African army ant Dorylus molestus frequently merge with neighbouring colonies after queen loss. Merging colonies often have no direct co-ancestry, but are on average probably distantly related because of overall population viscosity. The alternative of male production by orphaned workers appears to be so inefficient that residual inclusive fitness of orphaned workers might be maximized by indiscriminately merging with neighbouring colonies to increase their reproductive success. We show that worker chemical recognition profiles remain similar after queen loss, but rapidly change into a mixed colony Gestalt odour after fusion, consistent with indiscriminate acceptance of alien workers that are no longer aggressive. We hypothesize that colony fusion after queen loss might be more widespread, especially in spatially structured populations of social insects where worker reproduction is not profitable. PMID:19889701

  1. Interaction between Workers during a Short Time Window Is Required for Bacterial Symbiont Transmission in Acromyrmex Leaf-Cutting Ants

    PubMed Central

    Marsh, Sarah E.; Poulsen, Michael; Pinto-Tomás, Adrián; Currie, Cameron R.

    2014-01-01

    Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry a Pseudonocardia Actinobacteria exosymbiont on their bodies that produces antifungal compounds that help inhibit specialized parasites of the ants' fungal garden. Major workers emerge from their pupal cases (eclose) symbiont-free, but exhibit visible Actinobacterial coverage within 14 days post-eclosion. Using subcolony experiments, we investigate exosymbiont transmission within Acromyrmex colonies. We found successful transmission to newly eclosed major workers fostered by major workers with visible Actinobacteria in all cases (100% acquiring, n = 19). In contrast, newly eclosed major workers reared without exosymbiont-carrying major workers did not acquire visible Actinobacteria (0% acquiring, n = 73). We further show that the majority of ants exposed to major workers with exosymbionts within 2 hours of eclosion acquired bacteria (60.7% acquiring, n = 28), while normal acquisition did not occur when exposure occurred later than 2 hours post-eclosion (0% acquiring, n = 18). Our findings show that transmission of exosymbionts to newly eclosed major workers occurs through interactions with exosymbiont-covered workers within a narrow time window after eclosion. This mode of transmission likely helps ensure the defensive function within colonies, as well as specificity and partner fidelity in the ant-bacterium association. PMID:25058579

  2. Interaction between workers during a short time window is required for bacterial symbiont transmission in Acromyrmex leaf-cutting ants.

    PubMed

    Marsh, Sarah E; Poulsen, Michael; Pinto-Tomás, Adrián; Currie, Cameron R

    2014-01-01

    Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry a Pseudonocardia Actinobacteria exosymbiont on their bodies that produces antifungal compounds that help inhibit specialized parasites of the ants' fungal garden. Major workers emerge from their pupal cases (eclose) symbiont-free, but exhibit visible Actinobacterial coverage within 14 days post-eclosion. Using subcolony experiments, we investigate exosymbiont transmission within Acromyrmex colonies. We found successful transmission to newly eclosed major workers fostered by major workers with visible Actinobacteria in all cases (100% acquiring, n = 19). In contrast, newly eclosed major workers reared without exosymbiont-carrying major workers did not acquire visible Actinobacteria (0% acquiring, n = 73). We further show that the majority of ants exposed to major workers with exosymbionts within 2 hours of eclosion acquired bacteria (60.7% acquiring, n = 28), while normal acquisition did not occur when exposure occurred later than 2 hours post-eclosion (0% acquiring, n = 18). Our findings show that transmission of exosymbionts to newly eclosed major workers occurs through interactions with exosymbiont-covered workers within a narrow time window after eclosion. This mode of transmission likely helps ensure the defensive function within colonies, as well as specificity and partner fidelity in the ant-bacterium association.

  3. Cryptic lineages hybridize for worker production in the harvester ant Messor barbarus

    PubMed Central

    Darras, Hugo; Aron, Serge

    2016-01-01

    The reproductive division of labour between queen and worker castes in social insects is a defining characteristic of eusociality and a classic example of phenotypic plasticity. Whether social insect larvae develop into queens or workers has long been thought to be determined by environmental cues, i.e. larvae are developmentally totipotent. Contrary to this paradigm, several recent studies have revealed that caste is determined by genotype in some ant species, but whether this is restricted to just a few exceptional species is still unclear. Here, we show that the Mediterranean harvester ant Messor barbarus possesses an unusual reproductive system, in which the female castes are genetically determined. Using both nuclear and mitochondrial data, we show that Iberian populations have two distinct, cryptic lineages. Workers are always inter-lineage hybrids whereas queens are always produced from pure-lineage matings. The results suggest that genetic caste determination may be more widespread in ants than previously thought, and that further investigation in other species is needed to understand the frequency and evolution of this remarkable reproductive system. PMID:27852941

  4. What counts for ants? How return behaviour and food search of Cataglyphis ants are modified by variations in food quantity and experience.

    PubMed

    Bolek, Siegfried; Wittlinger, Matthias; Wolf, Harald

    2012-09-15

    When finding more food than one is able to carry home, should one come back to the site to exploit it further? This question is crucial for central place foragers that provide for a home place with brood or nest mates. The benefit of returning has to be weighed against the chance of finding food elsewhere and the resources available. Desert ants Cataglyphis fortis are well-studied examples when it comes to navigating back and forth between their nest and a foraging area, due to their primary reliance on path integration in the open and featureless desert habitat. The ants use path integration not only for a safe return from their foraging trips but also for future returns to plentiful feeding sites. The direction from the nest that has previously yielded food items is preferred for future foraging trips, a phenomenon termed sector fidelity. What prompts the ants to return to a particular site, and how faithfully they search for that place, has not been well studied. We examine the evaluation of food sources in channel experiments by varying both the number of food items in a feeder and the number of visits to the feeder before testing search distances of foragers returning to the feeding site. Ants exhibited more focused searches for plentiful food sources than for sources with only few food items upon their first return visit. After several successful visits, the ants always searched thoroughly for the food source, independent of the amount of food offered. Thus, desert ants consider both food abundance and reliability of food encounter, with corroborative learning of reliability gradually overriding the initial preference for plentiful feeders. The density of food items appears to be used by the ants as a proxy for food abundance. On the level of our analysis, the searches performed in the experimental channels are indistinguishable from those performed in the open desert terrain. The present results not only demonstrate how otherwise well-studied desert ants

  5. Bigger Helpers in the Ant Cataglyphis bombycina: Increased Worker Polymorphism or Novel Soldier Caste?

    PubMed Central

    Molet, Mathieu; Maicher, Vincent; Peeters, Christian

    2014-01-01

    Introduction The mechanisms by which development favors or constrains the evolution of new phenotypes are incompletely understood. Polyphenic species may benefit from developmental plasticity not only regarding ecological advantages, but also potential for evolutionary diversification. For instance, the repeated evolution of novel castes in ants may have been facilitated by the existence of alternative queen and worker castes and their respective developmental programs. Material and Methods Cataglyphis bombycina is exceptional in its genus because winged queens and size-polymorphic workers occur together with bigger individuals having saber-shaped mandibles. We measured seven body parts in more than 150 individuals to perform a morphometric analysis and assess the developmental origin of this novel phenotype. Results Adults with saber-shaped mandibles differ from both workers and queens regarding the size of most body parts. Their relative growth rates are identical to workers for some pairs of body parts, and identical to queens for other pairs of body parts; critical sizes differ in all cases. Conclusions Big individuals are a third caste, i.e. soldiers, not major workers. Novel traits such as elongated mandibles are combined with a mix of queen and worker growth rates. We also reveal the existence of a dimorphism in the queen caste (microgynes and macrogynes). We discuss how novel phenotypes can evolve more readily in the context of an existing polyphenism. Both morphological traits and growth rules from existing queen and worker castes can be recombined, hence mosaic phenotypes are more likely to be viable. In C. bombycina, such a mosaic phenotype appears to function both for defense (saber-shaped mandibles) and fat storage (big abdomen). Recycling of developmental programs may have contributed to the morphological diversity and ecological success of ants. PMID:24404196

  6. Division of labour influences the rate of ageing in weaver ant workers.

    PubMed Central

    Chapuisat, Michel; Keller, Laurent

    2002-01-01

    The evolutionary theory of ageing predicts that the timing of senescence has been primarily shaped by the extrinsic mortality rate, which causes selection intensity to decline over time. One difficulty in testing the evolutionary theory of ageing is that extrinsic mortality risk is often confounded with body size and fecundity, which may also directly affect lifespan. Social insects with a pronounced division of labour between worker castes provide a unique opportunity to study the direct effect of extrinsic mortality on the evolution of ageing rates independently of body size, reproductive effort and genetic configuration. In the weaver ant, Oecophylla smaragdina, the major (large) workers perform the risky tasks outside the nest, while the minor (small) workers stay within the highly protected arboreal nest. Hence, this pronounced division of labour is associated with high differences in extrinsic mortality risks. The evolutionary theory of ageing predicts that the minor workers should have a longer intrinsic lifespan than the major workers. In line with this prediction, we found that in a protected environment the minor workers lived significantly longer than the major workers did. Hence, the ageing rate appears to have been moulded by variation in the extrinsic mortality rate independently of size, reproductive effort and genetic configuration. PMID:12028773

  7. An oral bioassay for the toxicity of hydramethylnon to individual workers and queens of Argentine ants, Linepithema humile.

    PubMed

    Hooper-Bùi, L M; Rust, M K

    2001-11-01

    We have developed an oral bioassay to determine the toxicity of hydramethylnon to individual workers and queens of the Argentine ant, Linepithema humile. We fed seven concentrations of hydramethylnon in suspension to individual workers or queens, determined the amount of hydramethylnon ingested and evaluated the individual ants for mortality 14 days later. At concentrations > or = 0.37 g liter-1, the amount of liquid the queens ingested decreased dramatically, indicating that Argentine ant queens may detect hydramethylnon. Significantly larger volumes of the two highest concentrations of the hydramethylnon suspension were ingested by the workers, compared to the lower concentrations, suggesting that hydramethylnon may act as a feeding stimulant for the workers. Worker mortality was higher than queen mortality at the highest concentrations tested. The highest worker mortality resulted when the ants ingested 1.03 micrograms of hydramethylnon per mg of ant tissue. At the highest concentration (1.0 g liter-1) tested, workers ingested almost 12 times as much active ingredient per mg of body weight as did queens, suggesting that, in order to increase mortality of queens, multiple feedings must occur.

  8. Workers select mates for queens: a possible mechanism of gene flow restriction between supercolonies of the invasive Argentine ant

    NASA Astrophysics Data System (ADS)

    Sunamura, Eiriki; Hoshizaki, Sugihiko; Sakamoto, Hironori; Fujii, Takeshi; Nishisue, Koji; Suzuki, Shun; Terayama, Mamoru; Ishikawa, Yukio; Tatsuki, Sadahiro

    2011-05-01

    Some invasive ants form large networks of mutually non-aggressive nests, i.e., supercolonies. The Argentine ant Linepithema humile forms much larger supercolonies in introduced ranges than in its native range. In both cases, it has been shown that little gene flow occurs between supercolonies of this species, though the mechanism of gene flow restriction is unknown. In this species, queens do not undertake nuptial flight, and males have to travel to foreign nests and cope with workers before gaining access to alien queens. In this study, we hypothesized that male Argentine ants receive interference from workers of alien supercolonies. To test this hypothesis, we conducted behavioral and chemical experiments using ants from two supercolonies in Japan. Workers attacked males from alien supercolonies but not those from their own supercolonies. The level of aggression against alien males was similar to that against alien workers. The frequency of severe aggression against alien males increased as the number of recipient workers increased. Cuticular hydrocarbon profiles, which serve as cues for nestmate recognition, of workers and males from the same supercolony were very similar. Workers are likely to distinguish alien males from males of their own supercolony using the profiles. It is predicted that males are subject to considerable aggression from workers when they intrude into the nests of alien supercolonies. This may be a mechanism underlying the restricted gene flow between supercolonies of Argentine ants. The Argentine ant may possess a distinctive reproductive system, where workers participate in selecting mates for their queens. We argue that the aggression of workers against alien males is a novel form of reproductive interference.

  9. Workers select mates for queens: a possible mechanism of gene flow restriction between supercolonies of the invasive Argentine ant.

    PubMed

    Sunamura, Eiriki; Hoshizaki, Sugihiko; Sakamoto, Hironori; Fujii, Takeshi; Nishisue, Koji; Suzuki, Shun; Terayama, Mamoru; Ishikawa, Yukio; Tatsuki, Sadahiro

    2011-05-01

    Some invasive ants form large networks of mutually non-aggressive nests, i.e., supercolonies. The Argentine ant Linepithema humile forms much larger supercolonies in introduced ranges than in its native range. In both cases, it has been shown that little gene flow occurs between supercolonies of this species, though the mechanism of gene flow restriction is unknown. In this species, queens do not undertake nuptial flight, and males have to travel to foreign nests and cope with workers before gaining access to alien queens. In this study, we hypothesized that male Argentine ants receive interference from workers of alien supercolonies. To test this hypothesis, we conducted behavioral and chemical experiments using ants from two supercolonies in Japan. Workers attacked males from alien supercolonies but not those from their own supercolonies. The level of aggression against alien males was similar to that against alien workers. The frequency of severe aggression against alien males increased as the number of recipient workers increased. Cuticular hydrocarbon profiles, which serve as cues for nestmate recognition, of workers and males from the same supercolony were very similar. Workers are likely to distinguish alien males from males of their own supercolony using the profiles. It is predicted that males are subject to considerable aggression from workers when they intrude into the nests of alien supercolonies. This may be a mechanism underlying the restricted gene flow between supercolonies of Argentine ants. The Argentine ant may possess a distinctive reproductive system, where workers participate in selecting mates for their queens. We argue that the aggression of workers against alien males is a novel form of reproductive interference.

  10. Restaurant manager and worker food safety certification and knowledge.

    PubMed

    Brown, Laura G; Le, Brenda; Wong, Melissa R; Reimann, David; Nicholas, David; Faw, Brenda; Davis, Ernestine; Selman, Carol A

    2014-11-01

    Over half of foodborne illness outbreaks occur in restaurants. To combat these outbreaks, many public health agencies require food safety certification for restaurant managers, and sometimes workers. Certification entails passing a food safety knowledge examination, which is typically preceded by food safety training. Current certification efforts are based on the assumption that certification leads to greater food safety knowledge. The Centers for Disease Control and Prevention conducted this study to examine the relationship between food safety knowledge and certification. We also examined the relationships between food safety knowledge and restaurant, manager, and worker characteristics. We interviewed managers (N=387) and workers (N=365) about their characteristics and assessed their food safety knowledge. Analyses showed that certified managers and workers had greater food safety knowledge than noncertified managers and workers. Additionally, managers and workers whose primary language was English had greater food safety knowledge than those whose primary language was not English. Other factors associated with greater food safety knowledge included working in a chain restaurant, working in a larger restaurant, having more experience, and having more duties. These findings indicate that certification improves food safety knowledge, and that complex relationships exist among restaurant, manager, and worker characteristics and food safety knowledge.

  11. Restaurant Manager and Worker Food Safety Certification and Knowledge

    PubMed Central

    Brown, Laura G.; Le, Brenda; Wong, Melissa R.; Reimann, David; Nicholas, David; Faw, Brenda; Davis, Ernestine; Selman, Carol A.

    2017-01-01

    Over half of foodborne illness outbreaks occur in restaurants. To combat these outbreaks, many public health agencies require food safety certification for restaurant managers, and sometimes workers. Certification entails passing a food safety knowledge examination, which is typically preceded by food safety training. Current certification efforts are based on the assumption that certification leads to greater food safety knowledge. The Centers for Disease Control and Prevention conducted this study to examine the relationship between food safety knowledge and certification. We also examined the relationships between food safety knowledge and restaurant, manager, and worker characteristics. We interviewed managers (N = 387) and workers (N = 365) about their characteristics and assessed their food safety knowledge. Analyses showed that certified managers and workers had greater food safety knowledge than noncertified managers and workers. Additionally, managers and workers whose primary language was English had greater food safety knowledge than those whose primary language was not English. Other factors associated with greater food safety knowledge included working in a chain restaurant, working in a larger restaurant, having more experience, and having more duties. These findings indicate that certification improves food safety knowledge, and that complex relationships exist among restaurant, manager, and worker characteristics and food safety knowledge. PMID:25361386

  12. Fertility signaling—the proximate mechanism of worker policing in a clonal ant

    NASA Astrophysics Data System (ADS)

    Hartmann, Anne; D'Ettorre, Patrizia; Jones, Graeme R.; Heinze, Jürgen

    2005-06-01

    In eusocial insects, the ability to regulate reproduction relies on cues that signal the presence of fertile individuals. We investigated the variation of cuticular hydrocarbons (CHCs) with reproductive status in Platythyrea punctata, an ant, in which all workers are capable of producing daughters from unfertilized eggs (thelytoky). Who reproduces is determined through dominance and worker policing. New reproductives, which developed their ovaries after separation from an old reproductive for a short period of time, were attacked by nonreproductives upon reintroduction into their colony. In contrast, aggression against new reproductives with fully developed ovaries, which had been separated over a longer period, was initiated by fights between old and new reproductives. CHC profiles varied with ovarian development. New reproductives were only attacked when they expressed a CHC profile similar to old reproductives, but not when it was similar to that of nonreproductives. CHCs appear to signal the fertility of individuals and induce policing behavior towards surplus reproductive workers.

  13. Ants detect but do not discriminate diseased workers within their nest

    NASA Astrophysics Data System (ADS)

    Leclerc, Jean-Baptiste; Detrain, Claire

    2016-08-01

    Social insects have evolved an array of individual and social behaviours that limit pathogen entrance and spread within the colony. The detection of ectoparasites or of fungal spores on a nestmate body triggers their removal by allogrooming and appears as a primary component of social prophylaxis. However, in the case of fungal infection, one may wonder whether ant workers are able to detect, discriminate and keep at bay diseased nestmates that have no spores over their cuticle but which constitute a latent sanitary risk due to post-mortem corpse sporulation. Here, we investigate the ability of Myrmica rubra workers to detect and discriminate a healthy from a diseased nestmate infected by the entomopathogen Metarhizium anisopliae. During dyadic encounters in a neutral location, workers were more aggressive towards isolated sick nestmates on the 3rd post-infection day. However, no such detection or discrimination of fungus-infected nestmates occurred in a social context inside the nest or at the nest entrance. Gatekeepers never actively rejected incoming diseased nestmates that rather spontaneously isolated themselves outside the nest. Our study reveals that ant workers may detect health-dependent cues and that their `acceptance level' of sick nestmates is tunable depending on the social context. This raises questions about possible trade-offs between a social closure to pathogens and risks of erroneous rejection of healthy nestmates. Social isolation of moribund ants also appears as a widespread prophylactic strategy of social insects allowing them to reduce exposure to pathogens and to spare costs associated with the management of infected individuals.

  14. Ants detect but do not discriminate diseased workers within their nest.

    PubMed

    Leclerc, Jean-Baptiste; Detrain, Claire

    2016-08-01

    Social insects have evolved an array of individual and social behaviours that limit pathogen entrance and spread within the colony. The detection of ectoparasites or of fungal spores on a nestmate body triggers their removal by allogrooming and appears as a primary component of social prophylaxis. However, in the case of fungal infection, one may wonder whether ant workers are able to detect, discriminate and keep at bay diseased nestmates that have no spores over their cuticle but which constitute a latent sanitary risk due to post-mortem corpse sporulation. Here, we investigate the ability of Myrmica rubra workers to detect and discriminate a healthy from a diseased nestmate infected by the entomopathogen Metarhizium anisopliae. During dyadic encounters in a neutral location, workers were more aggressive towards isolated sick nestmates on the 3rd post-infection day. However, no such detection or discrimination of fungus-infected nestmates occurred in a social context inside the nest or at the nest entrance. Gatekeepers never actively rejected incoming diseased nestmates that rather spontaneously isolated themselves outside the nest. Our study reveals that ant workers may detect health-dependent cues and that their 'acceptance level' of sick nestmates is tunable depending on the social context. This raises questions about possible trade-offs between a social closure to pathogens and risks of erroneous rejection of healthy nestmates. Social isolation of moribund ants also appears as a widespread prophylactic strategy of social insects allowing them to reduce exposure to pathogens and to spare costs associated with the management of infected individuals.

  15. Dominance Hierarchies in Leptothorax Ants

    NASA Astrophysics Data System (ADS)

    Cole, Blaine J.

    1981-04-01

    The social organization of Leptothorax allardycei is unique among ant species thus far studied. The workers form linear dominance hierarchies characterized by routine displays of dominance, avoidance behavior, and even fighting. The high-ranking ants are favored in liquid food exchange, have greater ovarian development, and produce 20 percent of the eggs.

  16. Colony fusion in Argentine ants is guided by worker and queen cuticular hydrocarbon profile similarity.

    PubMed

    Vásquez, Gissella M; Schal, Coby; Silverman, Jules

    2009-08-01

    Introduced populations of the Argentine ant, Linepithema humile, have experienced moderate to severe losses of genetic diversity, which may have affected nestmate recognition to various degrees. We hypothesized that cuticular hydrocarbons (CHC) serve as nestmate recognition cues, and facilitate colony fusion of unrelated L. humile colonies that share similar CHC profiles. In this study, we paired six southeastern U.S. L. humile colonies in a 6-month laboratory fusion assay, and determined if worker and queen CHC profile similarity between colonies was associated with colony fusion and intercolony genetic similarity. We also compared worker and queen CHC profiles between fused colony pairs and unpaired controls to determine if worker and queen chemical profiles changed after fusion. We found that colony fusion correlated with the CHC similarity of workers and queens, with the frequency of fusion increasing with greater CHC profile similarity between colonies. Worker and queen CHC profile similarity between colonies also was associated with genetic similarity between colonies. Queen CHC profiles in fused colonies appeared to be a mix of the two colony phenotypes. In contrast, when only one of the paired colonies survived, the CHC profile of the surviving queens did not diverge from that of the colony of origin. Similarly, workers in non-fused colonies maintained their colony-specific CHC, whereas in fused colonies the worker CHC profiles were intermediate between those of the two colonies. These results suggest a role for CHC in regulating interactions among mutually aggressive L. humile colonies, and demonstrate that colony fusion correlates with both genetic and CHC similarities. Further, changes in worker and queen chemical profiles in fused colonies suggest that CHC plasticity may sustain the cohesion of unrelated L. humile colonies that had fused.

  17. Non-Enzymatic Hydrolysis of RNA in Workers of the Ant Nylanderia pubens

    PubMed Central

    Valles, Steven M.; Strong, Charles A.; Buss, Eileen A.; Oi, David H.

    2012-01-01

    During preparation of total RNA from Nylanderia pubens (Forel) (Hymenoptera: Formicidae) workers for use in expression library construction, severe RNA degradation consistently occurred. This degradation was masked by spectrophotometric analysis but clearly evident by microfluidic-based assay. Although not specifically identified, the degrading entity was endogenous and localized to the abdomen (terminal abdominal segments) of adult ants. RNA degradation was not observed in preparations of larvae, non-melanized pupae, or eggs. Various RNase and protease inhibitors had no protective effect. However, the metal chelating agent ethylenediaminetetraacetic acid prevented RNA degradation and provides insight into the occurrence. PMID:23461820

  18. Blessings on the Food, Blessings on the Workers: Arts-Based Education for Migrant Worker Justice

    ERIC Educational Resources Information Center

    Barndt, Deborah

    2013-01-01

    Migrant agricultural workers are not only on the margins of Canadian and global food systems; they are also on the margins of public consciousness about the labour behind the food we eat. Even local food movement groups who advocate for both social justice and sustainable food production have not made migrant labour a priority concern. Popular…

  19. Performance of the species-typical alarm response in young workers of the ant Myrmica sabuleti (Hymenoptera: Formicidae) is induced by interactions with mature workers.

    PubMed

    Cammaerts, Marie-Claire

    2014-01-01

    Young workers of the ant Myrmica sabuleti (Hymenoptera: Formicidae) Meinert 1861 perceived nestmate alarm pheromone but did not display normal alarm behavior (orientation toward the source of emission, increased running speed). They changed their initial behavior when in the presence of older nestmates exhibiting normal alarm behavior. Four days later, the young ants exhibited an imperfect version of normal alarm behavior. This change of behavior did not occur in young ants, which were not exposed to older ants reacting to alarm pheromone. Queen ants perceived the alarm pheromone and, after a few seconds, moved toward its source. Thus, the ants' ability to sense the alarm pheromone and to identify it as an alarm signal is native, while the adult alarm reaction is acquired over time (= age based polyethism) by young ants. It is possible that the change in behavior observed in young ants could be initiated and/or enhanced (via experience-induced developmental plasticity, learning, and/or other mechanisms) by older ants exhibiting alarm behavior. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  20. Food preference and foraging activity of ants: recommendations for field applications of low-toxicity baits.

    PubMed

    Nyamukondiwa, Casper; Addison, Pia

    2014-04-10

    Control of ants using baits of low toxicity cannot be effective without knowledge of bait distribution patterns and bait station densities, which are determined by ants' foraging activities. Furthermore, the success of toxic baits also depends upon attractiveness of bait carriers. Here, we assessed ground and vine foraging activity and food preferences for the three ant species ( Linepithema humile (Mayr) (Hymenoptera: Formicidae), Anoplolepis custodiens (F. Smith) and Crematogaster peringueyi Emery) under field conditions. We found that L. humile's vineyard foraging activity was high and that movement of ant bait by C. peringueyi and A. custodiens in the vineyard was relatively low. Consequently, more bait stations need to be dispensed for more effective control of C. peringueyi and A. custodiens than for L. humile. Different bait densities are discussed for the various ant species. Food preference trials indicated that vineyard foraging ants preferred wet bait attractants over dry ones, making liquids the most ideal carriers for baiting these ants. Linepithema humile was attracted to 25% sugar water, while C. peringueyi was attracted to both 25% sugar water and honey. Anoplolepis custodiens was attracted to tuna but was also attracted to 25% sugar water. Thus, future bait formulations should be tailor made to suit these specific food requirements if baits are to be successful in ant pest management.

  1. Food Preference and Foraging Activity of Ants: Recommendations for Field Applications of Low-Toxicity Baits

    PubMed Central

    Nyamukondiwa, Casper; Addison, Pia

    2014-01-01

    Control of ants using baits of low toxicity cannot be effective without knowledge of bait distribution patterns and bait station densities, which are determined by ants' foraging activities. Furthermore, the success of toxic baits also depends upon attractiveness of bait carriers. Here, we assessed ground and vine foraging activity and food preferences for the three ant species (Linepithema humile (Mayr) (Hymenoptera: Formicidae), Anoplolepis custodiens (F. Smith) and Crematogaster peringueyi Emery) under field conditions. We found that L. humile's vineyard foraging activity was high and that movement of ant bait by C. peringueyi and A. custodiens in the vineyard was relatively low. Consequently, more bait stations need to be dispensed for more effective control of C. peringueyi and A. custodiens than for L. humile. Different bait densities are discussed for the various ant species. Food preference trials indicated that vineyard foraging ants preferred wet bait attractants over dry ones, making liquids the most ideal carriers for baiting these ants. Linepithema humile was attracted to 25% sugar water, while C. peringueyi was attracted to both 25% sugar water and honey. Anoplolepis custodiens was attracted to tuna but was also attracted to 25% sugar water. Thus, future bait formulations should be tailor made to suit these specific food requirements if baits are to be successful in ant pest management. PMID:25373195

  2. Extreme genetic differences between queens and workers in hybridizing Pogonomyrmex harvester ants.

    PubMed Central

    Helms Cahan, Sara; Parker, Joel D; Rissing, Steven W; Johnson, Robert A; Polony, Tatjana S; Weiser, Michael D; Smith, Deborah R

    2002-01-01

    The process of reproductive caste determination in eusocial insect colonies is generally understood to be mediated by environmental, rather than genetic factors. We present data demonstrating unexpected genetic differences between reproductive castes in a variant of the rough harvester ant, Pogonomyrmex rugosus var. fuscatus. Across multiple loci, queens were consistently more homozygous than expected, while workers were more heterozygous. Adult colony queens were divided into two highly divergent genetic groups, indicating the presence of two cryptic species, rather than a single population. The observed genetic differences between castes reflect differential representation of heterospecific and conspecific patrilines in these offspring groups. All workers were hybrids; by contrast, winged queens were nearly all pure-species. The complete lack of pure-species workers indicates a loss of worker potential in pure-species female offspring. Hybrids appear to be bipotential, but do not normally develop into reproductives because they are displaced by pure-species females in the reproductive pool. Genetic differences between reproductive castes are expected to be rare in non-hybridizing populations, but within hybrid zones they may be evolutionarily stable and thus much more likely to occur. PMID:12350248

  3. Food Production Worker. Dietetic Support Personnel Training Program.

    ERIC Educational Resources Information Center

    Barker, Ellen; And Others

    This curriculum guide, part of a multi-volume dietetic support personnel training program, consists of materials (15 units) for use in training future food production workers. Covered in the first part of the guide are nutrition in food production and diet therapy. The second part of the guide deals with sanitation and safety in food production.…

  4. Food Production Worker. Dietetic Support Personnel Training Program.

    ERIC Educational Resources Information Center

    Barker, Ellen; And Others

    This curriculum guide, part of a multi-volume dietetic support personnel training program, consists of materials (15 units) for use in training future food production workers. Covered in the first part of the guide are nutrition in food production and diet therapy. The second part of the guide deals with sanitation and safety in food production.…

  5. Ant trophallactic networks: simultaneous measurement of interaction patterns and food dissemination

    NASA Astrophysics Data System (ADS)

    Greenwald, Efrat; Segre, Enrico; Feinerman, Ofer

    2015-07-01

    Eusocial societies and ants, in particular, maintain tight nutritional regulation at both individual and collective levels. The mechanisms that underlie this control are far from trivial since, in these distributed systems, information about the global supply and demand is not available to any single individual. Here we present a novel technique for non-intervening frequent measurement of the food load of all individuals in an ant colony, including during trophallactic events in which food is transferred by mouth-to-mouth feeding. Ants are imaged using a dual camera setup that produces both barcode-based identification and fluorescence measurement of labeled food. This system provides detailed measurements that enable one to quantitatively study the adaptive food distribution network. To demonstrate the capabilities of our method, we present sample observations that were unattainable using previous techniques, and could provide insight into the mechanisms underlying food exchange.

  6. Ant trophallactic networks: simultaneous measurement of interaction patterns and food dissemination

    PubMed Central

    Greenwald, Efrat; Segre, Enrico; Feinerman, Ofer

    2015-01-01

    Eusocial societies and ants, in particular, maintain tight nutritional regulation at both individual and collective levels. The mechanisms that underlie this control are far from trivial since, in these distributed systems, information about the global supply and demand is not available to any single individual. Here we present a novel technique for non-intervening frequent measurement of the food load of all individuals in an ant colony, including during trophallactic events in which food is transferred by mouth-to-mouth feeding. Ants are imaged using a dual camera setup that produces both barcode-based identification and fluorescence measurement of labeled food. This system provides detailed measurements that enable one to quantitatively study the adaptive food distribution network. To demonstrate the capabilities of our method, we present sample observations that were unattainable using previous techniques, and could provide insight into the mechanisms underlying food exchange. PMID:26224025

  7. Performance of the Species-Typical Alarm Response in Young Workers of the Ant Myrmica sabuleti (Hymenoptera: Formicidae) Is Induced by Interactions with Mature Workers

    PubMed Central

    Cammaerts, Marie-Claire

    2014-01-01

    Young workers of the ant Myrmica sabuleti (Hymenoptera: Formicidae) Meinert 1861 perceived nestmate alarm pheromone but did not display normal alarm behavior (orientation toward the source of emission, increased running speed). They changed their initial behavior when in the presence of older nestmates exhibiting normal alarm behavior. Four days later, the young ants exhibited an imperfect version of normal alarm behavior. This change of behavior did not occur in young ants, which were not exposed to older ants reacting to alarm pheromone. Queen ants perceived the alarm pheromone and, after a few seconds, moved toward its source. Thus, the ants’ ability to sense the alarm pheromone and to identify it as an alarm signal is native, while the adult alarm reaction is acquired over time (= age based polyethism) by young ants. It is possible that the change in behavior observed in young ants could be initiated and/or enhanced (via experience-induced developmental plasticity, learning, and/or other mechanisms) by older ants exhibiting alarm behavior. PMID:25525102

  8. Are variations in cuticular hydrocarbons of queens and workers a reliable signal of fertility in the ant Harpegnathos saltator?

    PubMed Central

    Liebig, Jürgen; Peeters, Christian; Oldham, Neil J.; Markstädter, Claus; Hölldobler, Bert

    2000-01-01

    One of the key features of insect societies is the division of labor in reproduction between one or a few fertile individuals and many sterile nestmates that function as helpers. The behavioral and physiological mechanisms regulating reproduction in ant societies are still not very well understood, especially in species in which all colony members are reproductively totipotent. In the ponerine ant Harpegnathos saltator, queen-worker dimorphism is very limited, and a few mated workers reproduce (“gamergates”) once the founding queen becomes senescent. Worker oviposition is regulated by highly directed aggressive interactions among nestmates, who can recognize different levels of ovarian activity. We show that variations in cuticular hydrocarbons (CHC) correlate with oogenesis, both for queens and workers. 13,23-Dimethylheptatriacontane is present in egg-layers, but not in infertile workers and queens. Proportions of other CHCs vary as well, resulting in clear separation of the ants in a multivariate analysis. Egg-layers are characterized by an elongation of the chain length of CHCs. We used solid-phase microextraction to measure CHCs in live ants that were experimentally induced to start producing eggs. Over a period of 118 days, CHC profiles of infertile workers changed completely to that of reproductives. The effect of age can be excluded in this modification. This striking correlation of ovarian activity with CHC variation and its correspondence with the observed recognition behavior exhibited by the workers toward egg-laying nestmates suggests that CHCs serve as a fertility signal in the ant H. saltator, a reliable basis for regulating reproduction. PMID:10760282

  9. Stable isotopes reveal links between human food inputs and urban ant diets

    PubMed Central

    Penick, Clint A.; Savage, Amy M.; Dunn, Robert R.

    2015-01-01

    The amount of energy consumed within an average city block is an order of magnitude higher than that consumed in any other ecosystem over a similar area. This is driven by human food inputs, but the consequence of these resources for urban animal populations is poorly understood. We investigated the role of human foods in ant diets across an urbanization gradient in Manhattan using carbon and nitrogen stable isotopes. We found that some—but not all—ant species living in Manhattan's most urbanized habitats had δ13C signatures associated with processed human foods. In particular, pavement ants (Tetramorium sp. E) had increased levels of δ13C similar to δ13C levels in human fast foods. The magnitude of this effect was positively correlated with urbanization. By contrast, we detected no differences in δ15N, suggesting Tetramorium feeds at the same trophic level despite shifting to human foods. This pattern persisted across the broader ant community; species in traffic islands used human resources more than park species. Our results demonstrate that the degree urban ants exploit human resources changes across the city and among species, and this variation could play a key role in community structure and ecosystem processes where human and animal food webs intersect. PMID:25833850

  10. Stable isotopes reveal links between human food inputs and urban ant diets.

    PubMed

    Penick, Clint A; Savage, Amy M; Dunn, Robert R

    2015-05-07

    The amount of energy consumed within an average city block is an order of magnitude higher than that consumed in any other ecosystem over a similar area. This is driven by human food inputs, but the consequence of these resources for urban animal populations is poorly understood. We investigated the role of human foods in ant diets across an urbanization gradient in Manhattan using carbon and nitrogen stable isotopes. We found that some-but not all-ant species living in Manhattan's most urbanized habitats had δ(13)C signatures associated with processed human foods. In particular, pavement ants (Tetramorium sp. E) had increased levels of δ(13)C similar to δ(13)C levels in human fast foods. The magnitude of this effect was positively correlated with urbanization. By contrast, we detected no differences in δ(15)N, suggesting Tetramorium feeds at the same trophic level despite shifting to human foods. This pattern persisted across the broader ant community; species in traffic islands used human resources more than park species. Our results demonstrate that the degree urban ants exploit human resources changes across the city and among species, and this variation could play a key role in community structure and ecosystem processes where human and animal food webs intersect. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. Ant larvae regulate worker foraging behavior and ovarian activity in a dose-dependent manner.

    PubMed

    Ulrich, Yuko; Burns, Dominic; Libbrecht, Romain; Kronauer, Daniel J C

    2016-07-01

    Division of labor in insect societies relies on simple behavioral rules, whereby individual colony members respond to dynamic signals indicating the need for certain tasks to be performed. This in turn gives rise to colony-level phenotypes. However, empirical studies quantifying colony-level signal-response dynamics are lacking. Here, we make use of the unusual biology and experimental amenability of the queenless clonal raider ant Cerapachys biroi, to jointly quantify the behavioral and physiological responses of workers to a social signal emitted by larvae. Using automated behavioral quantification and oocyte size measurements in colonies of different sizes and with different worker to larvae ratios, we show that the workers in a colony respond to larvae by increasing foraging activity and inhibiting ovarian activation in a progressive manner, and that these responses are stronger in smaller colonies. This work adds to our knowledge of the processes that link plastic individual behavioral/physiological responses to colony-level phenotypes in social insect colonies.

  12. Ant larvae regulate worker foraging behavior and ovarian activity in a dose-dependent manner

    PubMed Central

    Ulrich, Yuko; Burns, Dominic; Libbrecht, Romain; Kronauer, Daniel J. C.

    2015-01-01

    Division of labor in insect societies relies on simple behavioral rules, whereby individual colony members respond to dynamic signals indicating the need for certain tasks to be performed. This in turn gives rise to colony-level phenotypes. However, empirical studies quantifying colony-level signal-response dynamics are lacking. Here, we make use of the unusual biology and experimental amenability of the queenless clonal raider ant Cerapachys biroi, to jointly quantify the behavioral and physiological responses of workers to a social signal emitted by larvae. Using automated behavioral quantification and oocyte size measurements in colonies of different sizes and with different worker to larvae ratios, we show that the workers in a colony respond to larvae by increasing foraging activity and inhibiting ovarian activation in a progressive manner, and that these responses are stronger in smaller colonies. This work adds to our knowledge of the processes that link plastic individual behavioral/physiological responses to colony-level phenotypes in social insect colonies. PMID:27616809

  13. On the morphology of the worker immatures of the leafcutter ant Atta sexdens Linnaeus (Hymenoptera: Formicidae).

    PubMed

    Solis, Daniel Russ; Fox, Eduardo Gonçalves Paterson; Ceccato, Marcela; Reiss, Itamar Cristina; Décio, Pâmela; Lorenzon, Natalia; Da Silva, Natiele Gonçalves; Bueno, Odair Correa

    2012-08-01

    Leafcutter ants of the genus Atta Fabricius are serious agricultural pests. Morphological studies of immature stages within this group are few, and the data provided for species of considerable importance are usually incomplete. In this study, the immatures of Atta sexdens Linnaeus are described and compared using light and scanning electron microscopy. Only specimens from founding stage colonies (i.e., lacking adult workers) were used. The existence of four larval instars was estimated by a frequency plot of maximum head widths, and the larvae of different instars differed from each other mainly by their bodily dimensions. Worker larvae belonged to two distinct morphological castes: (1) gardeners and nurses and (2) within-nest generalists. The worker larvae described in this study differed from a previous description of the same species by the following traits: the existence of a genal lobe, the number of clypeal hairs, the presence of two hairs on the ninth abdominal somite, the presence of hairs on the anterior surface of the labrum, and the shape of the maxillary palpus. This study provides a comparative analysis of immature stages of A. sexdens that may be relevant to future morphological and biological studies of the Attini.

  14. Listening to food workers: Factors that impact proper health and hygiene practice in food service.

    PubMed

    Clayton, Megan L; Clegg Smith, Katherine; Neff, Roni A; Pollack, Keshia M; Ensminger, Margaret

    2015-01-01

    Foodborne disease is a significant problem worldwide. Research exploring sources of outbreaks indicates a pronounced role for food workers' improper health and hygiene practice. To investigate food workers' perceptions of factors that impact proper food safety practice. Interviews with food service workers in Baltimore, MD, USA discussing food safety practices and factors that impact implementation in the workplace. A social ecological model organizes multiple levels of influence on health and hygiene behavior. Issues raised by interviewees include factors across the five levels of the social ecological model, and confirm findings from previous work. Interviews also reveal many factors not highlighted in prior work, including issues with food service policies and procedures, working conditions (e.g., pay and benefits), community resources, and state and federal policies. Food safety interventions should adopt an ecological orientation that accounts for factors at multiple levels, including workers' social and structural context, that impact food safety practice.

  15. Listening to food workers: Factors that impact proper health and hygiene practice in food service

    PubMed Central

    Clegg Smith, Katherine; Neff, Roni A.; Pollack, Keshia M.; Ensminger, Margaret

    2015-01-01

    Background Foodborne disease is a significant problem worldwide. Research exploring sources of outbreaks indicates a pronounced role for food workers' improper health and hygiene practice. Objective To investigate food workers' perceptions of factors that impact proper food safety practice. Method Interviews with food service workers in Baltimore, MD, USA discussing food safety practices and factors that impact implementation in the workplace. A social ecological model organizes multiple levels of influence on health and hygiene behavior. Results Issues raised by interviewees include factors across the five levels of the social ecological model, and confirm findings from previous work. Interviews also reveal many factors not highlighted in prior work, including issues with food service policies and procedures, working conditions (e.g., pay and benefits), community resources, and state and federal policies. Conclusion Food safety interventions should adopt an ecological orientation that accounts for factors at multiple levels, including workers' social and structural context, that impact food safety practice. PMID:26243248

  16. Nest and food search behaviour in desert ants, Cataglyphis: a critical comparison.

    PubMed

    Pfeffer, Sarah E; Bolek, Siegfried; Wolf, Harald; Wittlinger, Matthias

    2015-07-01

    North African desert ants, Cataglyphis, use path integration to calculate a home vector during their foraging trips, constantly informing them about their position relative to the nest. This home vector is also used to find the way back to a productive feeding site the ant has encountered and thus memorized. When the animal fails to arrive at its goal after having run off the home or food vector, a systematic search is initiated. The basic search strategies are identical for nest and food searches, consisting of a search spiral superimposed by a random walk. While nest searches have been investigated in much detail, food site searches have received comparatively little attention. Here, we quantify and compare nest and food site searches recorded under similar conditions, particularly constant nest-feeder distance, and we observe notable differences in nest and food search performances. The parameters of nest searches are relatively constant and improve little with experience, although those small improvements had not been recognized previously. Food searches, by contrast, are more flexible and cover smaller or larger areas, mainly depending on the reliability of food encounter over several visits. Intriguingly, food site searches may be significantly more focussed than nest searches, although the nest should be the most important goal in an ant's life. These results demonstrate both adaptability and high accuracy of the ants' search programme.

  17. First evidence for slave rebellion: enslaved ant workers systematically kill the brood of their social parasite protomognathus americanus.

    PubMed

    Achenbach, Alexandra; Foitzik, Susanne

    2009-04-01

    During the process of coevolution, social parasites have evolved sophisticated strategies to exploit the brood care behavior of their social hosts. Slave-making ant queens invade host colonies and kill or eject all adult host ants. Host workers, which eclose from the remaining brood, are tricked into caring for the parasite brood. Due to their high prevalence and frequent raids, following which stolen host broods are similarly enslaved, slave-making ants exert substantial selection upon their hosts, leading to the evolution of antiparasite adaptations. However, all host defenses shown to date are active before host workers are parasitized, whereas selection was thought to be unable to act on traits of already enslaved hosts. Yet, here we demonstrate the rebellion of enslaved Temnothorax workers, which kill two-thirds of the female pupae of the slave-making ant Protomognathus americanus. Thereby, slaves decrease the long-term parasite impact on surrounding related host colonies. This novel antiparasite strategy of enslaved workers constitutes a new level in the coevolutionary battle after host colony defense has failed. Our discovery is analogous to recent findings in hosts of avian brood parasites where perfect mimicry of parasite eggs leads to the evolution of chick recognition as a second line of defense.

  18. Serving the food nation: Exploring Body Mass Index in food service workers.

    PubMed

    Woodhall-Melnik, Julia; Cooke, Martin; Bigelow, Philip L

    2015-01-01

    Obesity is a public health concern in North America. Consumption of food prepared outside of the home is often discussed as a contributing factor. To determine whether or not Canadian food service workers are more likely to have high Body Mass Indices (BMIs) as compared with the general population, and to examine factors that contribute to BMI in this population. Analyses of secondary survey data from Cycle 5.1 of the Canadian Community Health Survey were performed. Descriptive statistics were generated to examine food service workers' risk of having above normal BMI compared to other Canadians. Logistic regression analysis was used to identify factors contributing to variation in BMI among food service workers. Analyses were stratified by age. Canadian food service workers are less likely to have BMIs in the overweight and obese ranges than the general population. Stratification by age demonstrated that this decreased risk can be attributed to the fact that food service workers tend to be younger than the general population. As age increases among food service workers, the odds of having a BMI in the overweight and obese ranges increases. Food service workers in general were not at higher risk for high BMI, but those between the ages of 41 and 64 are at higher risk of having a BMI in the overweight or obese ranges. The findings suggest that proximity to food service outlets may not be the most salient factor in explaining BMI.

  19. Food worker hand washing practices: an observation study.

    PubMed

    Green, Laura R; Selman, Carol A; Radke, Vincent; Ripley, Danny; Mack, James C; Reimann, David W; Stigger, Tammi; Motsinger, Michelle; Bushnell, Lisa

    2006-10-01

    Improvement of food worker hand washing practices is critical to the reduction of foodborne illness and is dependent upon a clear understanding of current hand washing practices. To that end, this study collected detailed observational data on food worker hand washing practices. Food workers (n = 321) were observed preparing food, and data were recorded on specific work activities for which hand washing is recommended (e.g., food preparation, handling dirty equipment). Data were also recorded on hand washing behaviors that occurred in conjunction with these work activities. Results indicated that workers engaged in approximately 8.6 work activities per hour for which hand washing is recommended. However, workers made hand washing attempts (i.e., removed gloves, if worn, and placed hands in running water) in only 32% of these activities and washed their hands appropriately (i.e., removed gloves, if worn, placed hands in running water, used soap, and dried hands) in only 27% of these work activities. Attempted and appropriate hand washing rates varied by work activity--they were significantly higher in conjunction with food preparation than other work activities (46 versus < or = 37% for attempted hand washing; 41 versus < or = 30% for appropriate hand washing) and were significantly lower in conjunction with touching the body than other work activities (13 versus > or = 27% for attempted hand washing; 10 versus > or = 23% for appropriate hand washing). Attempted and appropriate hand washing rates were significantly lower when gloves were worn (18 and 16%) than when gloves were not worn (37 and 30%). These findings suggest that the hand washing practices of food workers need to be improved, glove use may reduce hand washing, and restaurants should consider reorganizing their food preparation activities to reduce the frequency with which hand washing is needed.

  20. Queens defense by workers in the highly polygynous ant Crematogaster pygmaea (Hymenoptera: Myrmicinae).

    PubMed

    Martins Segundo, Glauco Bezerra; de Biseau, Jean-Christophe; Quinet, Yves

    2012-11-01

    Some aspects of the biology of Crematogaster pygmaea, a highly polydomous and polygynous ant, are more commonly found in monogynous species. One such characteristic is the high attractiveness of its queens. In this study, this attractiveness was assessed under varying experimental conditions to investigate the factors responsible for its expression and variation, and to identify the nature of queen attractiveness. It was shown (1) that C. pygmaea queens are highly attractive to the workers that cluster on and around them (retinue), (2) that the attractiveness of C. pygmaea queens is context-dependent, i.e., it increases with increasing degree of potential danger to the queen, (3) that the attractiveness signal of C. pygmaea queens is chemically based, and (4) that this signal is persistent and apparently not colony-specific. The proposed hypothesis is that the C. pygmaea queens constantly release an attractiveness signal that is "read" by the workers, in a dependent way linked to the context, and that the main function of this attractiveness is to protect queens. This protection would have a high adaptive value in the context of the social structure and the reproductive strategies in C. pygmaea.

  1. Ant Species Differences Determined by Epistasis between Brood and Worker Genomes

    PubMed Central

    Linksvayer, Timothy A.

    2007-01-01

    Epistasis arising from physiological interactions between gene products often contributes to species differences, particularly those involved in reproductive isolation. In social organisms, phenotypes are influenced by the genotypes of multiple interacting individuals. In theory, social interactions can give rise to an additional type of epistasis between the genomes of social partners that can contribute to species differences. Using a full-factorial cross-fostering design with three species of closely related Temnothorax ants, I found that adult worker size was determined by an interaction between the genotypes of developing brood and care-giving workers, i.e. intergenomic epistasis. Such intergenomic social epistasis provides a strong signature of coevolution between social partners. These results demonstrate that just as physiologically interacting genes coevolve, diverge, and contribute to species differences, so do socially interacting genes. Coevolution and conflict between social partners, especially relatives such as parents and offspring, has long been recognized as having widespread evolutionary effects. This coevolutionary process may often result in coevolved socially-interacting gene complexes that contribute to species differences. PMID:17912371

  2. Seasonality directs contrasting food collection behavior and nutrient regulation strategies in ants.

    PubMed

    Cook, Steven C; Eubanks, Micky D; Gold, Roger E; Behmer, Spencer T

    2011-01-01

    Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant.

  3. Seasonality Directs Contrasting Food Collection Behavior and Nutrient Regulation Strategies in Ants

    PubMed Central

    Cook, Steven C.; Eubanks, Micky D.; Gold, Roger E.; Behmer, Spencer T.

    2011-01-01

    Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant. PMID:21966522

  4. Immunological and respiratory changes in animal food processing workers.

    PubMed

    Zuskin, E; Kanceljak, B; Schachter, E N; Witek, T J; Maayani, S; Goswami, S; Marom, Z; Rienzi, N

    1992-01-01

    A group of 35 men employed in the processing of animal food was studied to assess the relation between respiratory findings and immunological status. The most frequent positive skin prick reactions to occupational allergens were to fish flour (82.9%), followed by carotene (77.1%), corn (65.7%), four-leaf clover (62.9%), sunflower (54.3%), chicken meat (31.4%), soy (28.6%), and yeast (22.7%). Increased total IgE serum levels were found in 14/35 (40.0%) animal food workers compared to 1/39 (2.6%) in a healthy population (p less than 0.01). A significantly higher prevalence of chronic respiratory symptoms was found among the exposed workers compared to control workers. There was however, no significant difference in the prevalence of chronic respiratory symptoms between animal food workers with positive and negative skin tests to house dust or to fish flour or among those with increased or normal IgE (except for dyspnea). The frequency of acute symptoms associated with the work shift was high among the animal food workers but similar by immunological status. There were significant mean across-shift reductions for all ventilatory capacity tests, being particularly pronounced for FEF25. Workers with positive skin tests to fish flour antigen had significantly larger across-shift reductions in FEF25 than workers with negative skin reactions. An aqueous extract of animal food dust caused a dose-related contractile response of isolated guinea pig tracheal muscle in vitro. Our data suggest that, in addition to any immunological response animal food dust may produce in vivo, it probably also causes direct irritant or pharmacological reactions on the airways as suggested by our in vitro data.

  5. Mathematical model for path selection by ants between nest and food source.

    PubMed

    Bodnar, Marek; Okińczyc, Natalia; Vela-Pérez, M

    2017-03-01

    Several models have been proposed to describe the behavior of ants when moving from nest to food sources. Most of these studies where based on numerical simulations with no mathematical justification. In this paper, we propose a mechanism for the formation of paths of minimal length between two points by a collection of individuals undergoing reinforced random walks taking into account not only the lengths of the paths but also the angles (connected to the preference of ants to move along straight lines). Our model involves reinforcement (pheromone accumulation), persistence (tendency to preferably follow straight directions in absence of any external effect) and takes into account the bifurcation angles of each edge (represented by a probability of willingness of choosing the path with the smallest angle). We describe analytically the results for 2 ants and different path lengths and numerical simulations for several ants. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Degenerate slave-makers, but nevertheless slave-makers? Host worker relatedness in the ant Myrmoxenus kraussei.

    PubMed

    Suefuji, Masaki; Heinze, Jürgen

    2015-03-01

    Socially parasitic ants of the formicoxenine genus Myrmoxenus exhibit considerable diversity in colony structure and life history. While some species are active slave-makers with many workers and others are workerless 'murder-parasites,' Myrmoxenus kraussei is considered as a 'degenerate slave-maker' because of its very low worker numbers. Here, we document that Temnothorax recedens host workers in single colonies of M. kraussei from Lago di Garda, Italy, exhibit significantly more genetic diversity than workers in unparasitized colonies. This raises the possibility that, despite its low worker numbers, M. kraussei may actively engage in slave raids in nature. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  7. Hand washing compliance among retail food establishment workers in Minnesota.

    PubMed

    Allwood, Paul B; Jenkins, Timothy; Paulus, Colleen; Johnson, Lars; Hedberg, Craig W

    2004-12-01

    Inadequate hand washing by food workers is an important contributing factor to foodborne disease outbreaks in retail food establishments (RFEs). We conducted a survey of RFEs to investigate the effect of hand washing training, availability of hand washing facilities, and the ability of the person in charge (PIC) to describe hand washing according to the Minnesota Food Code (food code) on workers' ability to demonstrate food code-compliant hand washing. Only 52% of the PICs could describe the hand washing procedure outlined in the food code, and only 48% of workers could demonstrate code-compliant hand washing. The most common problems observed were failure to wash for 20 s and failure to use a fingernail brush. There was a strong positive association between the PIC being a certified food manager and being able to describe the food code hand washing procedure (odds ratio [OR], 5.5; 95% confidence interval [CI], 2.2 to 13.7), and there was an even stronger association between the PIC being able to describe hand washing and workers being able to demonstrate code-compliant hand washing (OR, 15; 95% CI, 6 to 37). Significant associations were detected among correct hand washing demonstration, physical infrastructure for hand washing, and the hand washing training methods used by the establishment. However, the principal determinant of successful hand washing demonstration was the PIC's ability to describe proper hand washing procedure. These results suggest that improving hand washing practices among food workers will require interventions that address PIC knowledge of hand washing requirement and procedure and the development and implementation of effective hand washing training methods.

  8. Food searches and guiding structures in North African desert ants, Cataglyphis.

    PubMed

    Bolek, Siegfried; Wolf, Harald

    2015-06-01

    North African desert ants, Cataglyphis fortis, use path integration as their primary means of navigation. The ants also use landmarks when these are available to improve navigation accuracy. Extended landmarks, such as walls and channels, may serve further functions, for example, local guidance or triggering of local vectors. The roles of such structures were usually examined in homing animals but not during food searches. When searching for familiar feeding sites, Cataglyphis may show intriguing deviations from expected search performances. These may result from the presence of extended landmarks, namely experimental channels. Here we scrutinise this hypothesis of landmark guidance in food searches. We prevented the ants from seeing the channel walls by covering their eyes, except the dorsal rim area. This experiment was repeated in the open test field with an alley of black cylinders to extend our findings to a more normal foraging environment. Ants with covered eyes did not deviate from expected search performances, whereas ants with normal eyes extended their searches along the axis of the leading structures by 15-20%, in both channels and landmark alleys. This demonstrates that Cataglyphis orients along extended landmarks when searching for familiar food sources and alters its search pattern accordingly.

  9. Food Service Worker. Dietetic Support Personnel Achievement Test.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater.

    This guide contains a series of multiple-choice items and guidelines to assist instructors in composing criterion-referenced tests for use in the food service worker component of Oklahoma's Dietetic Support Personnel training program. Test items addressing each of the following occupational duty areas are provided: human relations; personal…

  10. Food Production Worker. Dietetic Support Personnel Achievement Test.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater.

    This guide contains a series of multiple-choice items and guidelines to assist instructors in composing criterion-referenced tests for use in the food production worker component of Oklahoma's Dietetic Support Personnel training program. Test items addressing each of the following occupational duty areas are provided: human relations; hygiene and…

  11. Food Service Worker. Dietetic Support Personnel Achievement Test.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater.

    This guide contains a series of multiple-choice items and guidelines to assist instructors in composing criterion-referenced tests for use in the food service worker component of Oklahoma's Dietetic Support Personnel training program. Test items addressing each of the following occupational duty areas are provided: human relations; personal…

  12. [Assessment of lunch served in the Workers' Food Program, Brazil].

    PubMed

    Savio, Karin Eleonora Oliveira; Costa, Teresa Helena Macedo da; Miazaki, Edina; Schmitz, Bethsáida de Abreu Soares

    2005-04-01

    In the light of the Workers' Food Program (WFP) growth and its recent review of nutritional parameters regulations, the study aimed at evaluating food intake in WFP through dietary assessment of lunch served in the program and workers' nutritional status. A cross-sectional study was carried out in a representative sample of workers in Brasilia, Federal District, Brazil. A total of 1,044 subjects who had lunch at 52 food and nutrition units were evaluated. Social-economic and demographic data were collected as well as anthropometric measures for calculating the Body Mass Index. Food intake was assessed by dish weight and direct observation of dish composition. Of all subjects, 43% had excess weight, 33.7% were overweight and 9.3% were obese. Males were most affected. Median lunch energy intake was 515 kcal in women and 736 kcal in men. Median dietary fiber intake was 6.0 g among women and 8.3 g among men, and median cholesterol intake was over 90 mg among subjects with excess weight. The results indicate that the study population who is often seen as healthy is at nutritional risk. Workers in WFP should be targeted for health promotion strategies using especially nutritionists' skills as educators.

  13. Food Production Worker. Dietetic Support Personnel Achievement Test.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater.

    This guide contains a series of multiple-choice items and guidelines to assist instructors in composing criterion-referenced tests for use in the food production worker component of Oklahoma's Dietetic Support Personnel training program. Test items addressing each of the following occupational duty areas are provided: human relations; hygiene and…

  14. Effects of predatory ants within and across ecosystems in bromeliad food webs.

    PubMed

    Gonçalves, Ana Z; Srivastava, Diane S; Oliveira, Paulo S; Romero, Gustavo Q

    2017-07-01

    Predation is one of the most fundamental ecological processes affecting biotic communities. Terrestrial predators that live at ecosystem boundaries may alter the diversity of terrestrial organisms, but they may also have cross-ecosystem cascading effects when they feed on organisms with complex life cycles (i.e. organisms that shift from aquatic juvenile stages to terrestrial adult stages) or inhibit female oviposition in the aquatic environment. The predatory ant Odontomachus hastatus establishes its colonies among roots of Vriesea procera, an epiphytic bromeliad species with water-filled tanks that shelters many terrestrial and aquatic organisms. Ants may impact terrestrial communities and deter adult insects from ovipositing in the water of bromeliads via consumptive and non-consumptive effects. Ants do not forage within the aquatic environment; thus, they may be more efficient predators on terrestrial organisms. Therefore, we predict that ants will have stronger effects on terrestrial than aquatic food webs. However, such effects may also be site contingent and depend on the local composition of food webs. To test our hypothesis, we surveyed bromeliads with and without O. hastatus colonies from three different coastal field sites in the Atlantic Forest of southeast Brazil, and quantified the effect of this predatory ant on the composition, density and richness of aquatic and terrestrial metazoans found in these bromeliads. We found that ants changed the composition and reduced the overall density of aquatic and terrestrial metazoans in bromeliad ecosystems. However, effects of ants on species diversity were contingent on site. In general terms, the effects of the ant on aquatic and terrestrial metazoan communities were similar in strength and magnitude. Ants reduced the density of virtually all aquatic functional groups, especially detritivore insects as well as metazoans that reach bromeliads through phoresy on the skin of terrestrial animals (i.e. Ostracoda

  15. Social chromosome variants differentially affect queen determination and the survival of workers in the fire ant Solenopsis invicta.

    PubMed

    Buechel, Séverine D; Wurm, Yanick; Keller, Laurent

    2014-10-01

    Intraspecific variation in social organization is common, yet the underlying causes are rarely known. An exception is the fire ant Solenopsis invicta in which the existence of two distinct forms of social colony organization is under the control of the two variants of a pair of social chromosomes, SB and Sb. Colonies containing exclusively SB/SB workers accept only one single queen and she must be SB/SB. By contrast, when colonies contain more than 10% of SB/Sb workers, they accept several queens but only SB/Sb queens. The variants of the social chromosome are associated with several additional important phenotypic differences, including the size, fecundity and dispersal strategies of queens, aggressiveness of workers, and sperm count in males. However, little is known about whether social chromosome variants affect fitness in other life stages. Here, we perform experiments to determine whether differential selection occurs during development and in adult workers. We find evidence that the Sb variant of the social chromosome increases the likelihood of female brood to develop into queens and that adult SB/Sb workers, the workers that cull SB/SB queens, are overrepresented in comparison to SB/SB workers. This demonstrates that supergenes such as the social chromosome can have complex effects on phenotypes at various stages of development.

  16. How Do Genomes Create Novel Phenotypes? Insights from the Loss of the Worker Caste in Ant Social Parasites

    PubMed Central

    Smith, Chris R.; Helms Cahan, Sara; Kemena, Carsten; Brady, Seán G.; Yang, Wei; Bornberg-Bauer, Erich; Eriksson, Ti; Gadau, Juergen; Helmkampf, Martin; Gotzek, Dietrich; Okamoto Miyakawa, Misato; Suarez, Andrew V.; Mikheyev, Alexander

    2015-01-01

    A central goal of biology is to uncover the genetic basis for the origin of new phenotypes. A particularly effective approach is to examine the genomic architecture of species that have secondarily lost a phenotype with respect to their close relatives. In the eusocial Hymenoptera, queens and workers have divergent phenotypes that may be produced via either expression of alternative sets of caste-specific genes and pathways or differences in expression patterns of a shared set of multifunctional genes. To distinguish between these two hypotheses, we investigated how secondary loss of the worker phenotype in workerless ant social parasites impacted genome evolution across two independent origins of social parasitism in the ant genera Pogonomyrmex and Vollenhovia. We sequenced the genomes of three social parasites and their most-closely related eusocial host species and compared gene losses in social parasites with gene expression differences between host queens and workers. Virtually all annotated genes were expressed to some degree in both castes of the host, with most shifting in queen-worker bias across developmental stages. As a result, despite >1 My of divergence from the last common ancestor that had workers, the social parasites showed strikingly little evidence of gene loss, damaging mutations, or shifts in selection regime resulting from loss of the worker caste. This suggests that regulatory changes within a multifunctional genome, rather than sequence differences, have played a predominant role in the evolution of social parasitism, and perhaps also in the many gains and losses of phenotypes in the social insects. PMID:26226984

  17. Occupational exposure to Aspergillus and aflatoxins among food-grain workers in India

    PubMed Central

    Malik, Abida; Ali, Sana; Shahid, Mohd; Bhargava, Rakesh

    2014-01-01

    Background: Aflatoxins are a metabolite of Aspergillus molds and are widespread in the natural environment. Workers who handle food grains are at increased risk of exposure to aflatoxins and subsequently certain respiratory conditions. In India, more than half of the employed population is engaged in some type of agricultural work, yet little known about the respiratory problems as a result of exposure to aflatoxins among workers who handle food grains in India. Objectives: The aim of this study was to determine the risk of occupational exposure to aflatoxins in food-grain workers compared to workers who are not occupationally exposed to food grains. Methods: Bronchoalveolar lavage (BAL) and serum samples from 46 food-grain workers and 44 non-food-grain workers were analyzed for the presence of aflatoxins. Microscopy and culture of BAL samples were performed to detect Aspergillus species. Results: Aflatoxins were detected in 32.6% of the food-grain workers and 9.1% of non food grain workers (P<0.01). A significant difference was also found in BAL culture for Aspergillus (P<0.01) between the two groups. About 47.8% of the food-grain workers and 11.4% of non-food-grain workers had chronic respiratory symptoms. Conclusion: Occupational exposure to aflatoxins in food-grain workers was found to be associated with the increased presence of respiratory symptoms. PMID:25000106

  18. Occupational exposure to Aspergillus and aflatoxins among food-grain workers in India.

    PubMed

    Malik, Abida; Ali, Sana; Shahid, Mohd; Bhargava, Rakesh

    2014-01-01

    Aflatoxins are a metabolite of Aspergillus molds and are widespread in the natural environment. Workers who handle food grains are at increased risk of exposure to aflatoxins and subsequently certain respiratory conditions. In India, more than half of the employed population is engaged in some type of agricultural work, yet little known about the respiratory problems as a result of exposure to aflatoxins among workers who handle food grains in India. The aim of this study was to determine the risk of occupational exposure to aflatoxins in food-grain workers compared to workers who are not occupationally exposed to food grains. Bronchoalveolar lavage (BAL) and serum samples from 46 food-grain workers and 44 non-food-grain workers were analyzed for the presence of aflatoxins. Microscopy and culture of BAL samples were performed to detect Aspergillus species. Aflatoxins were detected in 32·6% of the food-grain workers and 9·1% of non food grain workers (P<0·01). A significant difference was also found in BAL culture for Aspergillus (P<0·01) between the two groups. About 47·8% of the food-grain workers and 11·4% of non-food-grain workers had chronic respiratory symptoms. Occupational exposure to aflatoxins in food-grain workers was found to be associated with the increased presence of respiratory symptoms.

  19. Collective regulatory stock management and spatiotemporal dynamics of the food flow in ants.

    PubMed

    Buffin, Aurélie; Goldman, Serge; Deneubourg, Jean Louis

    2012-07-01

    The organization of complex societies requires constant information flow between individuals. The shape of the food web organizes itself according to the spatial distribution of the individuals and of the stocks. To understand how the spatial organization of the food stocks changes with the colony needs, we monitored the flow of radiolabeled sugar solution inside an ant nest at different degrees of starvation. The spatial dynamics of the food flow revealed stable patterns and fine-tuning regulation of the feeding process. The complex collective regulatory stock management task can be reproduced by a surprising simple model that integrates a positive and a negative feedback proportional to the number of ants that already received food. Spatial analysis of the food distribution showed that sucrose is heterogeneously stocked among individuals and also heterogeneously consumed. Furthermore, we observed a regular spatial structure, leading to centralization of the stocks: heavily loaded individuals being at the center of the cluster and weakly loaded individuals at its periphery. The centralization of both resources and information in self-organized systems might be a widespread phenomenon that deserves further studies.

  20. Reduced foraging investment as an adaptation to patchy food sources: A phasic army ant simulation.

    PubMed

    Teseo, Serafino; Delloro, Francesco

    2017-09-07

    Colonies of several ant species within the subfamily Dorylinae alternate stereotypical discrete phases of foraging and reproduction. Such phasic cycles are thought to be adaptive because they minimize the amount of foraging and the related costs, and at the same time enhance the colony-level ability to rely on patchily distributed food sources. In order to investigate these hypotheses, we use here a simple computational approach to study the population dynamics of two species of virtual ant colonies that differ quantitatively in their foraging investment. One species, which we refer to as "phasic", forages only half of the time, mirroring the phasic activity of some army ants; the other "non-phasic" species forages instead all the time. We show that, when foraging costs are relatively high, populations of phasic colonies grow on average faster than non-phasic populations, outcompeting them in mixed populations. Interestingly, such tendency becomes more consistent as food becomes more difficult to find but locally abundant. According to our results, reducing the foraging investment, for example by adopting a phasic lifestyle, can result in a reproductive advantage, but only in specific conditions. We thus suggest phasic colony cycles to have emerged together with the doryline specialization in feeding on the brood of other eusocial insects, a resource that is hard to obtain but highly abundant if available. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 7. Barriers to reduce contamination of food by workers.

    PubMed

    Todd, Ewen C D; Michaels, Barry S; Greig, Judy D; Smith, Debra; Holah, John; Bartleson, Charles A

    2010-08-01

    Contamination of food and individuals by food workers has been identified as an important contributing factor during foodborne illness investigations. Physical and chemical barriers to prevent microbial contamination of food are hurdles that block or reduce the transfer of pathogens to the food surface from the hands of a food worker, from other foods, or from the environment. In food service operations, direct contact of food by hands should be prevented by the use of barriers, especially when gloves are not worn. Although these barriers have been used for decades in food processing and food service operations, their effectiveness is sometimes questioned or their use may be ignored. Physical barriers include properly engineered building walls and doors to minimize the flow of outside particles and pests to food storage and food preparation areas; food shields to prevent aerosol contamination of displayed food by customers and workers; work clothing designated strictly for work (clothing worn outdoors can carry undesirable microorganisms, including pathogens from infected family members, into the work environment); and utensils such as spoons, tongs, and deli papers to prevent direct contact between hands and the food being prepared or served. Money and ready-to-eat foods should be handled as two separate operations, preferably by two workers. Chemical barriers include sanitizing solutions used to remove microorganisms (including pathogens) from objects or materials used during food production and preparation and to launder uniforms, work clothes, and soiled linens. However, laundering as normally practiced may not effectively eliminate viral pathogens.

  2. Does exogenic food benefit both partners in an ant-plant mutualism? The case of Cecropia obtusa and its guest Azteca plant-ants.

    PubMed

    Dejean, Alain; Petitclerc, Frédéric; Roux, Olivier; Orivel, Jérôme; Leroy, Céline

    2012-03-01

    In the mutualisms involving the myrmecophyte Cecropia obtusa and Azteca ovaticeps or A. alfari, both predatory, the ants defend their host trees from enemies and provide them with nutrients (myrmecotrophy). A. ovaticeps provisioned with prey and then (15)N-enriched food produced more individuals than did control colonies (not artificially provisioned). This was not true for A. alfari colonies, possibly due to differences in the degree of maturity of the colonies for the chosen range of host tree sizes (less than 3m in height). Myrmecotrophy was demonstrated for both Azteca species as provisioning the ants with (15)N-enriched food translated into higher δ(15)N values in host plant tissues, indicating that nitrogen passed from the food to the plant. Thus, the predatory activity of their guest ants benefits the Cecropia trees not only because the ants protect them from defoliators since most prey are phytophagous insects but also because the plant absorbs nutrients. Copyright © 2012 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  3. Symbiotic bacteria on the cuticle of the leaf-cutting ant Acromyrmex subterraneus subterraneus protect workers from attack by entomopathogenic fungi

    PubMed Central

    Mattoso, Thalles C.; Moreira, Denise D. O.; Samuels, Richard I.

    2012-01-01

    Although only discovered in 1999, the symbiotic filamentous actinobacteria present on the integument of certain species of leaf-cutting ants have been the subject of intense research. These bacteria have been shown to specifically suppress fungal garden parasites by secretion of antibiotics. However, more recently, a wider role for these bacteria has been suggested from research revealing their generalist anti-fungal activity. Here we show, for the first time, evidence for a role of these bacteria in the defence of young worker ants against a fungal entomopathogen. Experimental removal of the bacterial bio-film using an antibiotic resulted in a significant increase in susceptibility of worker ants to infection by the entomopathogenic fungus Metarhizium anisopliae. This is the first direct evidence for the advantage of maintaining a bacterial bio-film on the cuticle as a defensive strategy of the ants themselves and not exclusively for protection of the fungus garden. PMID:22130174

  4. Symbiotic bacteria on the cuticle of the leaf-cutting ant Acromyrmex subterraneus subterraneus protect workers from attack by entomopathogenic fungi.

    PubMed

    Mattoso, Thalles C; Moreira, Denise D O; Samuels, Richard I

    2012-06-23

    Although only discovered in 1999, the symbiotic filamentous actinobacteria present on the integument of certain species of leaf-cutting ants have been the subject of intense research. These bacteria have been shown to specifically suppress fungal garden parasites by secretion of antibiotics. However, more recently, a wider role for these bacteria has been suggested from research revealing their generalist anti-fungal activity. Here we show, for the first time, evidence for a role of these bacteria in the defence of young worker ants against a fungal entomopathogen. Experimental removal of the bacterial bio-film using an antibiotic resulted in a significant increase in susceptibility of worker ants to infection by the entomopathogenic fungus Metarhizium anisopliae. This is the first direct evidence for the advantage of maintaining a bacterial bio-film on the cuticle as a defensive strategy of the ants themselves and not exclusively for protection of the fungus garden.

  5. Amphotis marginata (Coleoptera: Nitidulidae) a highwayman of the ant Lasius fuliginosus.

    PubMed

    Hölldobler, Bert; Kwapich, Christina L

    2017-01-01

    The space occupied by evolutionarily advanced ant societies can be subdivided into functional sites, such as broodchambers; peripheral nest chambers; kitchen middens; and foraging routes. Many predators and social parasites are specially adapted to make their living inside specific niches created by ants. In particular, the foraging paths of certain ant species are frequented by predatory and kleptoparasitic arthropods, including one striking example, the nitidulid beetle, Amphotis marginata. Adults of this species obtain the majority of their nutrition by acting as a kind of "highwayman" on the foraging trails of the ant Lasius fuliginosus, where they solicit regurgitation from food laden ant-workers by mimicking the ant's food-begging signals. Employing food labeled with the radio isotope 32P, we assessed the quantities of food the beetles siphoned-off of food-laden ants, and we investigated the site preferences, behavioral mechanisms and possible morphological adaptations underlying the food kleptoparasitism of A. marginata.

  6. Central American ants of the genus Megalomyrmex Forel (Hymenoptera: Formicidae): six new species and keys to workers and males.

    PubMed

    Boudinot, Brendon E; Sumnicht, Theodore P; Adams, Rachelle M M

    2013-11-04

    Megalomyrmex Forel is a distinctive lineage of Neotropical ants, some of which are specialized parasites or predators of the fungus-growing ants Attini. Here we review and key the Central American fauna. Six new species are described from both female castes: M. brandaoi sp. n., M. fungiraptor sp. n., M. longinoi sp. n., M. milenae sp. n., M. megadrifti sp. n. and M. osadrifti sp. n. A worker-based key to all Central American species is presented, and all species are illustrated. Megalomyrmex drifti Kempf is redescribed and the first descriptions of queens for M. miri Brandão and M. foreli Emery are provided. New biological information, several new geographic records, and a discussion of the species-group schema of Brandão (1990) are presented. The male sex of Megalomyrmex is diagnosed at the genus-level and keyed to species for the Central American fauna, where known. The male of each species treated in the key is diagnosed, described, or redescribed. Males are known for fourteen out of twenty total Central American Megalomyrmex species. A distinct but unassociated male is described and keyed (M. male 01). The males of M. miri Brandão and M. wettereri Brandão are described for the first time, and the distinctness of these two species is confirmed. One potential synapomorphy of Megalomyrmex present in males and workers is the presence of a carina which posteriorly delimits the basalmost region of the petiolar dorsum. 

  7. A queen pheromone induces workers to kill sexual larvae in colonies of the red imported fire ant (Solenopsis invicta)

    NASA Astrophysics Data System (ADS)

    Klobuchar, Emily; Deslippe, Richard

    2002-05-01

    We conducted five bioassays to study how queens control the execution of sexual larvae by workers in colonies of the red imported fire ant, Solenopsis invicta. In each assay, subset colonies were made from many large polygyne colonies, and the 20 sexual larvae they contained were monitored over time. Sexual larvae mostly survived in queenless colonies, but were mostly killed in colonies with a single dealated queen, regardless of whether or not the queen was fertilized. The larvae were also killed when fresh corpses of queens were added to queenless colonies. Whereas acetone extracts of queens did not produce a significant increase in killings, extracts in buffered saline induced workers to execute most sexual larvae, indicating successful extraction of an execution pheromone. We identified the probable storage location of the chemical as the poison sac, and found both fresh (1 day) and old (21 day) extracts of poison sacs to be equally effective in inducing executions. The pheromone is stable at room temperature, perhaps because venom alkaloids also present in the extracts keep the pheromone from degrading. It is apparently either proteinaceous or associated with a proteinaceous molecule, a novel finding, as no queen pheromone of a proteinaceous nature has been previously demonstrated in ants.

  8. Growth and patterning are evolutionarily dissociated in the vestigial wing discs of workers of the red imported fire ant, Solenopsis invicta.

    PubMed

    Bowsher, Julia H; Wray, Gregory A; Abouheif, Ehab

    2007-12-15

    Over the last decade, it has become clear that organismal form is largely determined by developmental and evolutionary changes in the growth and pattern formation of tissues. Yet, there is little known about how these two integrated processes respond to environmental cues or how they evolve relative to one another. Here, we present the discovery of vestigial wing imaginal discs in worker larvae of the red imported fire ant, Solenopsis invicta. These vestigial wing discs are present in all worker larvae, which is uncommon for a species with a large worker size distribution. Furthermore, the growth trajectory of these vestigial discs is distinct from all of the ant species examined to date because they grow at a rate slower than the leg discs. We predicted that the growth trajectory of the vestigial wing discs would be mirrored by evolutionary changes in their patterning. We tested this prediction by examining the expression of three patterning genes, extradenticle, ultrabithorax, and engrailed, known to underlie the wing polyphenism in ants. Surprisingly, the expression patterns of these three genes in the vestigial wing discs was the same as those found in ant species with different worker size distributions and wing disc growth than fire ants. We conclude that growth and patterning are evolutionarily dissociated in the vestigial wing discs of S. invicta because patterning in these discs is conserved, whereas their growth trajectories are not. The evolutionary dissociation of growth and patterning may be an important feature of gene networks that underlie polyphenic traits.

  9. Using a Training Video to Improve Agricultural Workers' Knowledge of On-Farm Food Safety

    ERIC Educational Resources Information Center

    Mathiasen, Lisa; Morley, Katija; Chapman, Benjamin; Powell, Douglas

    2012-01-01

    A training video was produced and evaluated to assess its impact on the food safety knowledge of agricultural workers. Increasing food safety knowledge on the farm may help to improve the safety of fresh produce. Surveys were used to measure workers' food safety knowledge before and after viewing the video. Focus groups were used to determine…

  10. Using a Training Video to Improve Agricultural Workers' Knowledge of On-Farm Food Safety

    ERIC Educational Resources Information Center

    Mathiasen, Lisa; Morley, Katija; Chapman, Benjamin; Powell, Douglas

    2012-01-01

    A training video was produced and evaluated to assess its impact on the food safety knowledge of agricultural workers. Increasing food safety knowledge on the farm may help to improve the safety of fresh produce. Surveys were used to measure workers' food safety knowledge before and after viewing the video. Focus groups were used to determine…

  11. Plant defense, herbivory, and the growth of Cordia alliodora trees and their symbiotic Azteca ant colonies.

    PubMed

    Pringle, Elizabeth G; Dirzo, Rodolfo; Gordon, Deborah M

    2012-11-01

    The effects of herbivory on plant fitness are integrated over a plant's lifetime, mediated by ontogenetic changes in plant defense, tolerance, and herbivore pressure. In symbiotic ant-plant mutualisms, plants provide nesting space and food for ants, and ants defend plants against herbivores. The benefit to the plant of sustaining the growth of symbiotic ant colonies depends on whether defense by the growing ant colony outpaces the plant's growth in defendable area and associated herbivore pressure. These relationships were investigated in the symbiotic mutualism between Cordia alliodora trees and Azteca pittieri ants in a Mexican tropical dry forest. As ant colonies grew, worker production remained constant relative to ant-colony size. As trees grew, leaf production increased relative to tree size. Moreover, larger trees hosted lower densities of ants, suggesting that ant-colony growth did not keep pace with tree growth. On leaves with ants experimentally excluded, herbivory per unit leaf area increased exponentially with tree size, indicating that larger trees experienced higher herbivore pressure per leaf area than smaller trees. Even with ant defense, herbivory increased with tree size. Therefore, although larger trees had larger ant colonies, ant density was lower in larger trees, and the ant colonies did not provide sufficient defense to compensate for the higher herbivore pressure in larger trees. These results suggest that in this system the tree can decrease herbivory by promoting ant-colony growth, i.e., sustaining space and food investment in ants, as long as the tree continues to grow.

  12. Missed Opportunities for Improving Nutrition Through Institutional Food: The Case for Food Worker Training

    PubMed Central

    Deutsch, Jonathan; Patinella, Stefania; Freudenberg, Nicholas

    2013-01-01

    The institutional food sector—including food served in schools, child care settings, hospitals, and senior centers—is a largely untapped resource for public health that may help to arrest increasing rates of obesity and diet-related health problems. To make this case, we estimated the reach of a diverse institutional food sector in 1 large municipality, New York City, in 2012, and explored the potential for improving institutional food by building the skills and nutritional knowledge of foodservice workers through training. Drawing on the research literature and preliminary data collected in New York City, we discuss the dynamics of nutritional decision-making in these settings. Finally, we identify opportunities and challenges associated with training the institutional food workforce to enhance nutrition and health. PMID:23865653

  13. Quantifying the Effect of Colony Size and Food Distribution on Harvester Ant Foraging

    PubMed Central

    Flanagan, Tatiana P.; Letendre, Kenneth; Burnside, William R.; Fricke, G. Matthew; Moses, Melanie E.

    2012-01-01

    Desert seed-harvester ants, genus Pogonomyrmex, are central place foragers that search for resources collectively. We quantify how seed harvesters exploit the spatial distribution of seeds to improve their rate of seed collection. We find that foraging rates are significantly influenced by the clumpiness of experimental seed baits. Colonies collected seeds from larger piles faster than randomly distributed seeds. We developed a method to compare foraging rates on clumped versus random seeds across three Pogonomyrmex species that differ substantially in forager population size. The increase in foraging rate when food was clumped in larger piles was indistinguishable across the three species, suggesting that species with larger colonies are no better than species with smaller colonies at collecting clumped seeds. These findings contradict the theoretical expectation that larger groups are more efficient at exploiting clumped resources, thus contributing to our understanding of the importance of the spatial distribution of food sources and colony size for communication and organization in social insects. PMID:22808035

  14. Quantifying the effect of colony size and food distribution on harvester ant foraging.

    PubMed

    Flanagan, Tatiana P; Letendre, Kenneth; Burnside, William R; Fricke, G Matthew; Moses, Melanie E

    2012-01-01

    Desert seed-harvester ants, genus Pogonomyrmex, are central place foragers that search for resources collectively. We quantify how seed harvesters exploit the spatial distribution of seeds to improve their rate of seed collection. We find that foraging rates are significantly influenced by the clumpiness of experimental seed baits. Colonies collected seeds from larger piles faster than randomly distributed seeds. We developed a method to compare foraging rates on clumped versus random seeds across three Pogonomyrmex species that differ substantially in forager population size. The increase in foraging rate when food was clumped in larger piles was indistinguishable across the three species, suggesting that species with larger colonies are no better than species with smaller colonies at collecting clumped seeds. These findings contradict the theoretical expectation that larger groups are more efficient at exploiting clumped resources, thus contributing to our understanding of the importance of the spatial distribution of food sources and colony size for communication and organization in social insects.

  15. Ants Use Partner Specific Odors to Learn to Recognize a Mutualistic Partner

    PubMed Central

    Hojo, Masaru K.; Yamamoto, Ari; Akino, Toshiharu; Tsuji, Kazuki; Yamaoka, Ryohei

    2014-01-01

    Regulation via interspecific communication is an important for the maintenance of many mutualisms. However, mechanisms underlying the evolution of partner communication are poorly understood for many mutualisms. Here we show, in an ant-lycaenid butterfly mutualism, that attendant ants selectively learn to recognize and interact cooperatively with a partner. Workers of the ant Pristomyrmex punctatus learn to associate cuticular hydrocarbons of mutualistic Narathura japonica caterpillars with food rewards and, as a result, are more likely to tend the caterpillars. However, the workers do not learn to associate the cuticular hydrocarbons of caterpillars of a non-ant-associated lycaenid, Lycaena phlaeas, with artificial food rewards. Chemical analysis revealed cuticular hydrocarbon profiles of the mutualistic caterpillars were complex compared with those of non-ant-associated caterpillars. Our results suggest that partner-recognition based on partner-specific chemical signals and cognitive abilities of workers are important mechanisms underlying the evolution and maintenance of mutualism with ants. PMID:24489690

  16. Ants use partner specific odors to learn to recognize a mutualistic partner.

    PubMed

    Hojo, Masaru K; Yamamoto, Ari; Akino, Toshiharu; Tsuji, Kazuki; Yamaoka, Ryohei

    2014-01-01

    Regulation via interspecific communication is an important for the maintenance of many mutualisms. However, mechanisms underlying the evolution of partner communication are poorly understood for many mutualisms. Here we show, in an ant-lycaenid butterfly mutualism, that attendant ants selectively learn to recognize and interact cooperatively with a partner. Workers of the ant Pristomyrmex punctatus learn to associate cuticular hydrocarbons of mutualistic Narathura japonica caterpillars with food rewards and, as a result, are more likely to tend the caterpillars. However, the workers do not learn to associate the cuticular hydrocarbons of caterpillars of a non-ant-associated lycaenid, Lycaena phlaeas, with artificial food rewards. Chemical analysis revealed cuticular hydrocarbon profiles of the mutualistic caterpillars were complex compared with those of non-ant-associated caterpillars. Our results suggest that partner-recognition based on partner-specific chemical signals and cognitive abilities of workers are important mechanisms underlying the evolution and maintenance of mutualism with ants.

  17. Non-enzymatic hydrolysis of RNA in workers of the ant Nylanderia pubens

    USDA-ARS?s Scientific Manuscript database

    During preparation of total RNA from Nylanderia pubens (Forel) workers for use in expression library construction, severe RNA degradation consistently occurred that was masked by spectrophotometric analysis but clearly evident by microfluidic-based assay. Although not specifically identified, the ...

  18. Amphotis marginata (Coleoptera: Nitidulidae) a highwayman of the ant Lasius fuliginosus

    PubMed Central

    Hölldobler, Bert

    2017-01-01

    The space occupied by evolutionarily advanced ant societies can be subdivided into functional sites, such as broodchambers; peripheral nest chambers; kitchen middens; and foraging routes. Many predators and social parasites are specially adapted to make their living inside specific niches created by ants. In particular, the foraging paths of certain ant species are frequented by predatory and kleptoparasitic arthropods, including one striking example, the nitidulid beetle, Amphotis marginata. Adults of this species obtain the majority of their nutrition by acting as a kind of “highwayman” on the foraging trails of the ant Lasius fuliginosus, where they solicit regurgitation from food laden ant-workers by mimicking the ant’s food-begging signals. Employing food labeled with the radio isotope 32P, we assessed the quantities of food the beetles siphoned-off of food-laden ants, and we investigated the site preferences, behavioral mechanisms and possible morphological adaptations underlying the food kleptoparasitism of A. marginata. PMID:28783744

  19. Effects of experimental seaweed deposition on lizard and ant predation in an island food web.

    PubMed

    Piovia-Scott, Jonah; Spiller, David A; Schoener, Thomas W

    2011-01-28

    The effect of environmental change on ecosystems is mediated by species interactions. Environmental change may remove or add species and shift life-history events, altering which species interact at a given time. However, environmental change may also reconfigure multispecies interactions when both species composition and phenology remain intact. In a Caribbean island system, a major manifestation of environmental change is seaweed deposition, which has been linked to eutrophication, overfishing, and hurricanes. Here, we show in a whole-island field experiment that without seaweed two predators--lizards and ants--had a substantially greater-than-additive effect on herbivory. When seaweed was added to mimic deposition by hurricanes, no interactive predator effect occurred. Thus environmental change can substantially restructure food-web interactions, complicating efforts to predict anthropogenic changes in ecosystem processes.

  20. 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.

  1. Allogrooming, Self-Grooming, and Touching Behavior: Contamination Routes of Leaf-Cutting Ant Workers Using a Fat-Soluble Tracer Dye

    PubMed Central

    Camargo, Roberto da Silva; Puccini, Carolina; Forti, Luiz Carlos; de Matos, Carlos Alberto Oliveira

    2017-01-01

    The aim of this study was to determine whether worker self-grooming, allogrooming, and direct contact promotes the dispersal of substances among members of the colony. For this purpose, a tracer (Sudan III dye) was applied topically to a worker ant and the social interactions between the worker with the tracer and workers without the tracer were studied. Additionally, the worker heads were dissected to visualize whether or not the post-pharyngeal gland was stained. The post-pharyngeal glands from 50% to 70% of workers were stained depending on the size of the group. With the increase in the experimental group size, the frequency of interactions between workers increased, with touching being the most frequent behavior. The tracer dye was probably passed on by direct contact between workers, followed by self-grooming and allogrooming. These behaviors are responsible for the rapid dispersal of substances among colony members as observed in our experiment. The results therefore support the hypothesis that contact with substances promotes the contamination of nestmates, even in the absence of feeding, serving as a model for further studies on the contamination of workers with the active ingredients of insecticides. PMID:28598375

  2. [Investigation of intestinal parasites in food workers in hospitals in Aydin, Turkey].

    PubMed

    Yazici, Vesile; Siriken, Fatih; Ertabaklar, Hatice; Ertuğ, Sema

    2007-01-01

    Food workers are an important risk group for intestinal parasite contamination and dissemination. In the present study food workers, working in food preparation and distribution in the Adnan Menderes University Hospital, Aydin State Hospital and 82. Yil State Hospital, were screened for the presence of intestinal parasites. Out of 58 food workers 22 were females and 36 were males, and the age of workers ranged from 20 to 56. All workers included in the study answered a questionnaire concerned with their social demographic situation and hygiene habits. Stool specimens and cellophane tape specimens were taken from food workers and studied for the presence of parasites. Stool samples were studied using native Lugol, precipitation by formol ethyl acetate, trichrome and acid fast staining methods. Cellophane tape slides were examined for Enterobius vermicularis with the 10X objective. Out of 58 food workers investi-gated, 17 (29.31%) had at least one parasite; nine had Blastocystis hominis (15.51%), five had E. vermicularis (8.62%), one had Giardia intestinalis (1.72%), one had both Entamoeba histolytica/dispar and Entamoeba coli (1.72%), and one had both E. vermicularis and B. hominis (1.72%). All workers with parasites were treated and taken under surveillance. The oral-fecal route is the main source for intes-tinal parasite contamination. It should be considered that food workers may be the main source for the contamination of hospital workers as well as patients which may cause serious problems especially for the cases with immune deficiency.

  3. Food Safety Education for Students and Workers in School Gardens and University Farms

    ERIC Educational Resources Information Center

    Dzubak, John; Shaw, Angela; Strohbehn, Catherine; Naeve, Linda

    2016-01-01

    The number of school gardens and university farms is increasing in the United States. Produce grown in these venues is often sampled in the classroom or incorporated into the food chain. Food safety education for students and workers is needed to ensure that produce is safe. Two 1-hr food safety curricula were developed to inform K-12 students and…

  4. Food Safety Education for Students and Workers in School Gardens and University Farms

    ERIC Educational Resources Information Center

    Dzubak, John; Shaw, Angela; Strohbehn, Catherine; Naeve, Linda

    2016-01-01

    The number of school gardens and university farms is increasing in the United States. Produce grown in these venues is often sampled in the classroom or incorporated into the food chain. Food safety education for students and workers is needed to ensure that produce is safe. Two 1-hr food safety curricula were developed to inform K-12 students and…

  5. "Pizza is cheaper than salad": assessing workers' views for an environmental food intervention.

    PubMed

    Devine, Carol M; Nelson, Janet A; Chin, Nancy; Dozier, Ann; Fernandez, Isabel Diana

    2007-11-01

    "Images of a Healthy Worksite" aims to provide easy access to healthful foods and to reduce sedentarism at the worksite-to prevent weight gain. Formative research for the nutrition intervention component was aimed at gaining a broad understanding of the sociocultural role of food and eating among workers and worker perspectives on socially feasible and culturally acceptable environmental intervention strategies. Using an adapted PRECEDE health planning model, we conducted ecological, educational, environmental, and administrative assessments at the worksite. Through 15 in-depth interviews, five focus groups, and community mapping at two sites with 79 administrators, managers, workers, and food service personnel (51% men, 82% white), we assessed workers' perspectives on physical, sociocultural, economic, and policy environments. Data were coded for predisposing, enabling, and reinforcing factors related to intervention strategies in vending, cafeteria, catering, and informal food environments. After classification for reach, intensity, and sustainability, objectives and evaluation plans were developed for each highly ranked strategy. Key sociocultural factors affecting food and eating included: stress-related eating in a downsizing workplace, enthusiasm for employer-sponsored weight gain prevention efforts that respect personal privacy, and the consequences of organizational culture on worker access to the food and eating environment. Workers supported healthier cafeteria and catering options, bringing healthful foods closer, and labeling of healthful options. We provide a practical and systematic approach to formative research and assess the interrelatedness of the physical, policy, economic, and sociocultural factors that affect environmental worksite interventions to prevent weight gain among employees.

  6. Evaluating the Influence of Nutrition Determinants on Construction Workers' Food Choices.

    PubMed

    Okoro, Chioma Sylvia; Musonda, Innocent; Agumba, Justus

    2016-01-27

    Nutritional knowledge as well as economic, social, biological, and cultural factors have been known to determine an individual's food choices. Despite the existence of research on the factors which influence nutrition globally, there is little known about the extent to which these factors influence the food choices of construction workers, which in turn influence their health and safety during construction activities. The present article investigates the extent to which construction workers' nutrition is influenced by nutritional knowledge, as well as economic, environmental, social, psychological, and physiological factors. A field questionnaire survey was conducted on site construction workers in the Gauteng Province of South Africa. Principal components analysis and multiple regression analysis were used to analyze the data. Findings revealed that consumption of foods termed alternative foods including dairy products, eggs, nuts, fish, and cereals, was influenced by nutritional knowledge and resources. Foods termed traditional core foods were influenced by cultural background; foods termed secondary core foods comprising fruits and vegetables were influenced by economic factors, resources, and cultural background; while foods termed core foods were mostly influenced by nutritional knowledge. By providing evidence of the factors which most influence selection and consumption of certain foods by construction workers, relevant nutrition interventions will be designed and implemented, taking cognizance of these factors.

  7. Lycaenid Caterpillar Secretions Manipulate Attendant Ant Behavior.

    PubMed

    Hojo, Masaru K; Pierce, Naomi E; Tsuji, Kazuki

    2015-08-31

    Mutualistic interactions typically involve the exchange of different commodities between species. Nutritious secretions are produced by a number of insects and plants in exchange for services such as defense. These rewards are valuable metabolically and can be used to reinforce the behavior of symbiotic partners that can learn and remember them effectively. We show here novel effects of insect exocrine secretions produced by caterpillars in modulating the behavior of attendant ants in the food-for-defense interaction between lycaenid butterflies and ants. Reward secretions from the dorsal nectary organ (DNO) of Narathura japonica caterpillars function to reduce the locomotory activities of their attendant ants, Pristomyrmex punctatus workers. Moreover, workers that feed from caterpillar secretions are significantly more likely to show aggressive responses to eversion of the tentacle organs of the caterpillars. Analysis of the neurogenic amines in the brains of workers that consumed caterpillar secretions showed a significant decrease in levels of dopamine compared with controls. Experimental treatments in which reserpine, a known inhibitor of dopamine in Drosophila, was fed to workers similarly reduced their locomotory activity. We conclude that DNO secretions of lycaenid caterpillars can manipulate attendant ant behavior by altering dopaminergic regulation and increasing partner fidelity. Unless manipulated ants also receive a net nutritional benefit from DNO secretions, this suggests that similar reward-for-defense interactions that have been traditionally considered to be mutualisms may in fact be parasitic in nature. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. A list of and some comments about the trail pheromones of ants.

    PubMed

    Cerdá, Xim; van Oudenhove, Louise; Bernstein, Carlos; Boulay, Raphaël R

    2014-08-01

    Ants use many different chemical compounds to communicate with their nestmates. Foraging success depends on how efficiently ants communicate the presence of food and thus recruit workers to exploit the food resource. Trail pheromones, produced by different exocrine glands, are a key part of ant foraging strategies. By combing through the literature, we compiled a list of the identity and glandular origin of the chemical compounds found in the trail pheromones of 75 different ant species. Of the 168 compounds identified, more than 40% are amines. In the subfamily Myrmicinae, trail pheromones are mostly produced in the venom gland, while in the subfamily Formicinae, they come from the rectal gland.

  9. Differences in sNPF receptor-expressing neurons in brains of fire ant (Solenopsis invicta Buren) worker subcastes: indicators for division of labor and nutritional status?

    PubMed

    Castillo, Paula; Pietrantonio, Patricia V

    2013-01-01

    In the red imported fire ant, Solenopsis invicta Buren, the neuronal and molecular mechanisms related to worker division of labor are poorly understood. Workers from different subcastes (major, medium and minors) perform different tasks, which are loosely associated with their size. We hypothesized that the short neuropeptide F (sNPF) signaling system (NPY-like) could be involved in mechanisms of worker division of labor and sensing or responding to colony nutritional requirements. Thus, we investigated the expression of the short neuropeptide F receptor (sNPFR) in the brain and subesophageal ganglion (SEG) of workers from colonies with and without brood. Across worker subcastes a total of 9 clusters of immunoreactive sNPFR cells were localized in the brain and the subesophageal ganglion (SEG); some of these cells were similar to those observed previously in the queen. Worker brain sNPFR cell clusters were found in the protocerebrum near mushroom bodies, in the central complex and in the lateral horn. Other sNPFR immunoreactive cells were found at the edge of the antennal lobes. Across subcastes, we observed both a constant and a differential pattern of sNPFR clusters, with a higher number of sNPFR cells found in minor than in major workers. Those sNPFR cells detected in all worker subcastes appear to be involved in olfaction or SEG functions. The differential expression of clusters in subcastes suggests that sNPFR signaling is involved in regulating behaviors associated with specific subcastes and thus, division of labor. Some sNPFR cells appear to be involved in nutrient sensing and/or brood care, feeding behavior and locomotion. In colonies without brood, workers showed a lower cluster number, and an overall reduced sNPFR signal. Our results suggest the sNPF signaling system is a candidate for the neurobiological control of worker division of labor and sensing brood presence, perhaps correlating with protein requirements and availability.

  10. A novel interference behaviour: invasive wasps remove ants from resources and drop them from a height

    PubMed Central

    Grangier, Julien; Lester, Philip J.

    2011-01-01

    This study reports a novel form of interference behaviour between the invasive wasp Vespula vulgaris and the New Zealand native ant Prolasius advenus. By videotaping interactions at bait stations, we found that wasps commonly remove ant competitors from food resources by picking up the workers in their mandibles, flying backward and dropping them unharmed some distance from the food. Both the frequency and the efficiency of the wasp behaviour significantly increased with the abundance of ant competitors. Ant removals were the most common interference events initiated by wasps when ants were numerous, while intraspecific conflicts among wasps were prominent when few ants were present. The ‘ant-dropping’ behaviour emphasizes how asymmetry in body sizes between competitors can lead to a pronounced form of interference, related to asymmetric locomotion modes. PMID:21450726

  11. A novel interference behaviour: invasive wasps remove ants from resources and drop them from a height.

    PubMed

    Grangier, Julien; Lester, Philip J

    2011-10-23

    This study reports a novel form of interference behaviour between the invasive wasp Vespula vulgaris and the New Zealand native ant Prolasius advenus. By videotaping interactions at bait stations, we found that wasps commonly remove ant competitors from food resources by picking up the workers in their mandibles, flying backward and dropping them unharmed some distance from the food. Both the frequency and the efficiency of the wasp behaviour significantly increased with the abundance of ant competitors. Ant removals were the most common interference events initiated by wasps when ants were numerous, while intraspecific conflicts among wasps were prominent when few ants were present. The 'ant-dropping' behaviour emphasizes how asymmetry in body sizes between competitors can lead to a pronounced form of interference, related to asymmetric locomotion modes.

  12. Tritrophic effects of birds and ants on a canopy food web, tree growth, and phytochemistry

    Treesearch

    Kailen A. Mooney

    2007-01-01

    Insectivorous birds and ants co-occur in most terrestrial communities, and theory predicts that emergent properties (i.e., nonadditive effects) can determine their combined influence on arthropods and plants. In a three-year factorial experiment, I investigated whether the effects of birds on pine and its arthropods differed based on the presence of ants that were...

  13. Evaluation of the nutritional status of workers of transformation industries adherent to the Brazilian Workers' Food Program. A comparative study.

    PubMed

    Bezerra, Ingrid W Leal; Oliveira, António Gouveia; Pinheiro, Liana G B; Morais, Célia M M; Sampaio, Luciano M B

    2017-01-01

    The objective of this study was to assess whether the Brazilian Workers' Food Program (WFP) is associated with changes in the nutritional status of workers in the transformation industry. We conducted a cross-sectional, observational, comparative study, based on prospectively collected data from a combined stratified and two-stage probability sample of workers from 26 small and medium size companies, 13 adherent and 13 non-adherent to the WFP, in the food, mining and textile sectors. Study variables were body mass index (BMI), waist circumference (WC), and dietary intake at lunch obtained by 24-hour dietary recall. Data were analyzed with nested mixed effects linear regression with adjustment by subject variables. Sampling weights were applied in computing population parameters. The final sample consisted of 1069 workers, 541 from WFP-adherent and 528 from WFP non-adherent companies. The groups were different only in education level, income and in-house training. Workers in WFP-adherent companies have greater BMI (27.0 kg/m2 vs. 26.0 kg/m2, p = 0.002) and WC (87.9 cm vs. 86.5, p = 0.04), higher prevalence of excessive weight (62.6% vs. 55.5%, p<0.001) and of increased WC (49.1% vs. 39.9%). Workers of WFP companies have lower intake of saturated fat (-1.34 g, p<0.01) and sodium (-0.3 g, p<0.01) at lunch. In conclusion, this study showed that workers of companies adherent to the Brazilian WFP have greater rates of excessive weight and increased cardiovascular risk-a negative finding-as well as lower intake of sodium and saturated fat-a positive finding. Therefore, the WFP needs to be revisited and its aims redefined according to the current epidemiological status of the target population of the program.

  14. Does farm worker health vary between localised and globalised food supply systems?

    PubMed

    Cross, Paul; Edwards, Rhiannon T; Opondo, Maggie; Nyeko, Philip; Edwards-Jones, Gareth

    2009-10-01

    Significant environmental benefits are claimed for local food systems, but these biophysical indicators are increasingly recognised as inadequate descriptors of supply chain ethics. Social factors such as health are also important indicators of good practice, and are recognised by the organic and local food movements as important to the development of rounded sustainable agricultural practices. This study compared the self-reported health status of farm workers in the United Kingdom, Spain, Kenya and Uganda who were supplying distant markets with fresh vegetables. Workers on Kenyan export horticulture farms reported significantly higher levels of physical health than did Kenyan non-export farm workers and workers in the other study countries. Mean health levels for farm workers in the United Kingdom were significantly lower than relevant population norms, indicating widespread levels of poor health amongst these workers. These results suggest that globalised supply chains can provide social benefits to workers, while local food systems do not always provide desirable social outcomes. The causal mechanisms of these observations probably relate more to the social conditions of workers than directly to income.

  15. Molecular epidemiology of microorganisms isolated from food workers and enteral feeding of public hospitals.

    PubMed

    Borges, Liana J; Campos, Maria Raquel H; Cardoso, Juliana L; André, Maria Cláudia D P B; Serafini, Álvaro B

    2010-09-01

    This study aimed to compare strains of Staphylococcus aureus and E. coli isolated from food workers and enteral diet samples obtained from 2 public hospitals (H1/H2) in Goiania, Goias, Brazil, by the means of antibiogram and pulsed field gel electrophoresis (PFGE). In the H1, strains of S. aureus were present in 2 enteral diet samples and in 13 food worker swabs. Strains of E. coli were found in an enteral diet sample from H1 and in 2 enteral diet samples from H2 and in 6 food worker swabs in the H1 and in 12 food worker swabs from H2. According to the antibiogram, the 6 susceptibility profiles (A to F) of 15 S. aureus strains colonizing personnel and enteral feeding did not allow the identification of the probable source of diet contamination. All 20 E. coli strains isolated from the H1 and H2 were grouped in 4 phenotypic profiles (A to D). The phenotypes A (H1) and C (H2) showed the same profile for microorganisms isolated from handlers and diets, suggesting more phenotypic similarity among these samples. PFGE genotyping showed that S. aureus isolates from diets were related to a single strain isolated from a food worker suggesting that in this case the reason for the diet contamination may be a result of food handling. The food worker appears to be the most probable source of E. coli contamination for enteral feeding from H2. This fact emphasizes on the food workers as a risk of bacterial transmission for the diets and that the diet chain production must be controlled. The study emphasizes the importance of monitoring the enteral diet microbiological quality and the factors associated to its contamination. The study highlights the use of molecular biology as an instrument to correlate strains to determine the origin of the final product contamination.

  16. Educating Immigrant Hispanic Foodservice Workers about Food Safety Using Visual-Based Training

    ERIC Educational Resources Information Center

    Rajagopal, Lakshman

    2013-01-01

    Providing food safety training to a diverse workforce brings with it opportunities and challenges that must be addressed. The study reported here provides evidence for benefits of using visual-based tools for food safety training when educating immigrant, Hispanic foodservice workers with no or minimal English language skills. Using visual tools…

  17. Educating Immigrant Hispanic Foodservice Workers about Food Safety Using Visual-Based Training

    ERIC Educational Resources Information Center

    Rajagopal, Lakshman

    2013-01-01

    Providing food safety training to a diverse workforce brings with it opportunities and challenges that must be addressed. The study reported here provides evidence for benefits of using visual-based tools for food safety training when educating immigrant, Hispanic foodservice workers with no or minimal English language skills. Using visual tools…

  18. Multilocus genetic characterization of two ant vectors (Group II "Dirty 22" species) known to contaminate food and food products and spread foodborne pathogens.

    PubMed

    Sulaiman, Irshad M; Anderson, Mickey; Oi, David H; Simpson, Steven; Kerdahi, Khalil

    2012-08-01

    The U.S. Food and Drug Administration utilizes the presence of filth and extraneous materials as one of the criteria for implementing regulatory actions and assessing adulteration of food products of public health importance. Twenty-two prevalent pest species (also known as the ''Dirty 22'' species) have been considered by this agency as possible vehicles for the spread of foodborne diseases, and the presence of these species is considered an indicator of unsanitary conditions in food processing and storage facilities. In a previous study, we further categorized the Dirty 22 species into four groups: group I includes four cockroach species, group II includes two ant species, group III includes 12 fly species, and group IV includes four rodent species. Here, we describe the development of three nested PCR primer sets and multilocus genetic characterization by amplifying the small subunit rRNA, elongation factor 1-alpha, and wingless (WNT-1) genes of group II Dirty 22 ant species Monomorium pharaonis and Solenopsis molesta. These novel group II Dirty 22 species-specific nested PCR primer sets can be used when the specimens cannot be identified using conventional microscopic methods. These newly developed assays will provide correct identification of group II Dirty 22 ant species, and the information can be used in the control of foodborne pathogens.

  19. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 8. Gloves as barriers to prevent contamination of food by workers.

    PubMed

    Todd, Ewen C D; Michaels, Barry S; Greig, Judy D; Smith, Debra; Bartleson, Charles A

    2010-09-01

    The role played by food workers and other individuals in the contamination of food has been identified as an important contributing factor leading to foodborne outbreaks. To prevent direct bare hand contact with food and food surfaces, many jurisdictions have made glove use compulsory for food production and preparation. When properly used, gloves can substantially reduce opportunities for food contamination. However, gloves have limitations and may become a source of contamination if they are punctured or improperly used. Experiments conducted in clinical and dental settings have revealed pinhole leaks in gloves. Although such loss of glove integrity can lead to contamination of foods and surfaces, in the food industry improper use of gloves is more likely than leakage to lead to food contamination and outbreaks. Wearing jewelry (e.g., rings) and artificial nails is discouraged because these items can puncture gloves and allow accumulation of microbial populations under them. Occlusion of the skin during long-term glove use in food operations creates the warm, moist conditions necessary for microbial proliferation and can increase pathogen transfer onto foods through leaks or exposed skin or during glove removal. The most important issue is that glove use can create a false sense of security, resulting in more high-risk behaviors that can lead to cross-contamination when employees are not adequately trained.

  20. Interspecific competition and coexistence between ants and land hermit crabs on small Bahamian islands

    NASA Astrophysics Data System (ADS)

    Morrison, Lloyd W.

    2002-08-01

    Numerous studies have demonstrated the existence of intra- and interspecific competition among ants, but few have investigated direct competitive interactions between ants and other taxa. In this paper, I present the first evidence of direct competitive interactions between ants and crabs. Evidence of competition for food between ants and the land hermit crab, Coenobita clypeatus (Herbst), was derived from observations and experiments in an archipelago of small islands in the central Exumas, Bahamas. Correlational evidence of competition for food based on occurrences at baits was found between ants and hermit crabs in multiple years. Observations at baits over time revealed species turnover occurred due to aggressive interactions. C. clypeatus discovered food items rapidly, but lost control of food over time, particularly to the ant Brachymyrmex obscurior Forel, which took longer to find food items but recruited large numbers of workers that drove off hermit crabs. A second ant species, Dorymyrmex pyramicus Roger, discovered baits quickly but did not recruit to baits in large numbers, and was not a superior competitor to either C. clypeatus or B. obscurior. Competition between ants and land hermit crabs was not intense enough to cause complementary distributions, and mechanisms of coexistence apparently include temporal variation in foraging activity and complementary foraging strategies when ants and crabs are active at the same time. Because of the widespread distributions and generalist scavenger diets of many ants and crabs, such competitive interactions are likely to be a common facet of many tropical and subtropical insular and coastal communities.

  1. Hand eczema as a risk factor for food allergy among occupational kitchen workers.

    PubMed

    Minami, Takafumi; Fukutomi, Yuma; Sekiya, Kiyoshi; Akasawa, Akira; Taniguchi, Masami

    2017-09-02

    An increasing number of studies in children is highlighting the importance of transdermal routes of exposure to food allergens through damaged skin in the pathogenesis of food allergies. However, data on this in adults are limited. A few case-series studies has documented development of food allergy among kitchen workers with hand eczema after direct contact exposure to foods. To explore the significance of hand eczema as a risk factor for food allergies in adults at the epidemiological level, we performed a cross-sectional web-based questionnaire survey on kitchen workers whose exposures were classed as occupational (cooks and food handlers, n = 1592) or non-occupational (housewives, n = 1915). Logistic regression was used to explore the association between the presence/severity of hand eczema and the risk of food allergy after adjustment for potential confounders. Current hand eczema and current diagnosed food allergy were more common among occupational kitchen workers (OKW) than among non-occupational kitchen workers (NOKW) (32.3%-vs-29.9% and 9.9%-vs-3.8%, respectively). Current hand eczema was significantly associated with increased risk of current diagnosed food allergy in OKW (adjusted odds ratio 2.4, 95% CI 1.6-3.7). Those with more severe hand eczema were more likely to suffer from allergic symptoms for foods, and diagnosed food allergy. This study illustrates a significant public health problem in the adult population, documenting a major impact of hand eczema on the ongoing adult food allergy epidemic. Copyright © 2017 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  2. Cloning and Expression of Multiple Cytochrome P450 Genes: Induction by Fipronil in Workers of the Red Imported Fire Ant (Solenopsis invicta Buren).

    PubMed

    Zhang, Baizhong; Zhang, Lei; Cui, Rukun; Zeng, Xinnian; Gao, Xiwu

    2016-01-01

    Both exogenous and endogenous compounds can induce the expression of cytochrome P450 genes. The insect cytochrome P450 genes related to insecticide resistance are likely to be expressed as the "first line of defense" when challenged with insecticides. In this study, four cytochrome P450 genes, SinvCYP6B1, SinvCYP6A1, SinvCYP4C1, and SinvCYP4G15, were firstly isolated from workers of the red imported fire ant (Solenopsis invicta) through rapid amplification of cDNA ends (RACE) and sequenced. The fipronil induction profiles of the four cytochrome P450 genes and the two previously isolated CYP4AB1 and CYP4AB2 were characterized in workers. The results revealed that the expression of SinvCYP6B1, SinvCYP6A1, CYP4AB2, and SinvCYP4G15, increased 1.4-fold and 1.3-fold more than those of acetone control, respectively, after 24 h exposure to fipronil at concentrations of 0.25 μg mL-1 (median lethal dose) and 0.56 μg mL-1 (90% lethal dose), while no significant induction of the expression of CYP4AB1 and SinvCYP4C1 was detected. Among these genes, SinvCYP6B1 was the most significantly induced, and its maximum expression was 3.6-fold higher than that in acetone control. These results might suggest that multiple cytochrome P450 genes are co-up-regulated in workers of the fire ant through induction mechanism when challenged with fipronil. These findings indicated that cytochrome P450 genes play an important role in the detoxification of insecticides and provide a theoretical basis for the mechanisms of insecticide metabolism in the fire ant.

  3. Current Cigarette Smoking Among Workers in Accommodation and Food Services--United States, 2011-2013.

    PubMed

    Syamlal, Girija; Jamal, Ahmed; Mazurek, Jacek M

    2015-07-31

    Tobacco use is the leading cause of preventable disease and death in the United States. One of the Healthy People 2020 objectives calls for reducing the proportion of U.S. adults who smoke cigarettes to ≤12% (objective TU-1.1). Despite progress in reducing smoking prevalence over the past several decades, nearly one in five U.S. adults, including millions of workers, still smoke cigarettes. During 2004-2010, nearly one fifth (19.6%) of U.S. working adults aged ≥18 years smoked cigarettes, and of all the industry sectors, current smoking prevalence among the accommodation and food services sector workers (30%) was the highest. CDC analyzed National Health Interview Survey (NHIS) data for 2011-2013 to estimate current cigarette smoking prevalence among adults working in the accommodation and food services sector, and found that these workers had higher cigarette smoking prevalence (25.9%) than all other workers (17.3%). Among workers in accommodation and food services sector, the highest smoking prevalences were observed among males, non-Hispanic whites, those aged 25-44 years, those with a high school diploma or a General Educational Development (GED) certificate and no college education, those with an annual family income <$35,000, those with no health insurance, and those working in the food services and drinking places industry. These results indicate a need to better understand the reasons for higher smoking prevalence observed among accommodation and food services workers (e.g., workplace culture), so that appropriate intervention strategies can be developed and implemented. Evidence suggests that smoke-free worksites and workplace cessation programs, including comprehensive worksite smoke-free policies, health promotion, access to smoking cessation programs, and increasing the cost of tobacco products, can substantially reduce smoking among workers.

  4. The Association between Socioeconomic Characteristics and Consumption of Food Items among Brazilian Industry Workers

    PubMed Central

    Vinholes, Daniele B.; Melo, Ione M. F.; Machado, Carlos Alberto; de Castro Chaves, Hilton; Fuchs, Flavio D.; Fuchs, Sandra C.

    2012-01-01

    Background. Dietary pattern plays a causative role in the rising of noncommunicable diseases. The SESI (Serviço Social da Indústria) study was designed to evaluate risk factors for noncommunicable diseases. We aimed to describe food items consumed by Brazilian workers and to assess their association with socioeconomic status. Methods. Cross-sectional study was carried out among Brazilian industrial workers, selected by multistage sampling, from 157 companies. Interviews were conducted at the work place using standardized forms. Results. 4818 workers were interviewed, aged 35.4 ± 10.7 years, 76.5% were men. The workers had an average of 8.7 ± 4.1 years of schooling and 25.4 ± 4.1 kg/m2 of BMI. Men and individuals with less than high school education were less likely to consume dairy products, fruits, and vegetables daily, even after control for confounding factors. Men consumed rice and beans daily more often than women. In comparison to workers aged 50–76 years, those under 30 years old consumed less fruits and green leafy vegetables daily. Conclusion. The food items consumed by Brazilian workers show that there are insufficient consumption according to the guidelines of healthy foods, particularly of dairy products, vegetables, and fruits. PMID:22701097

  5. Fluid intake rates in ants correlate with their feeding habits.

    PubMed

    Paul, J; Roces, F

    2003-04-01

    This study investigates the techniques of nectar feeding in 11 different ant species, and quantitatively compares fluid intake rates over a wide range of nectar concentrations in four species that largely differ in their feeding habits. Ants were observed to employ two different techniques for liquid food intake, in which the glossa works either as a passive duct-like structure (sucking), or as an up- and downwards moving shovel (licking). The technique employed for collecting fluids at ad libitum food sources was observed to be species-specific and to correlate with the presence or absence of a well-developed crop in the species under scrutiny. Workers of ponerine ants licked fluid food during foraging and transported it as a droplet between their mandibles, whereas workers of species belonging to phylogenetically more advanced subfamilies, with a crop capable of storing liquids, sucked the fluid food, such as formicine ants of the genus Camponotus. In order to evaluate the performance of fluid collection during foraging, intake rates for sucrose solutions of different concentrations were measured in four ant species that differ in their foraging ecology. Scaling functions between fluid intake rates and ant size were first established for the polymorphic species, so as to compare ants of different size across species. Results showed that fluid intake rate depended, as expected and previously reported in the literature, on sugar concentration and the associated fluid viscosity. It also depended on both the species-specific feeding technique and the extent of specialization on foraging on liquid food. For similarly-sized ants, workers of two nectar-feeding ant species, Camponotus rufipes (Formicinae) and Pachycondyla villosa (Ponerinae), collected fluids with the highest intake rates, while workers of the leaf-cutting ant Atta sexdens (Myrmicinae) and a predatory ant from the Rhytidoponera impressa-complex (Ponerinae) did so with the lowest rate. Calculating the

  6. Awareness of food nutritive value and eating practices among Nigerian bank workers

    PubMed Central

    Eze, Ngozi M.; Maduabum, Felicia O.; Onyeke, Nkechi G.; Anyaegunam, Ngozi J.; Ayogu, Chinwe A.; Ezeanwu, Bibian Amaka; Eseadi, Chiedu

    2017-01-01

    Abstract Adequate nutrition is an important aspect of a healthy lifestyle for all individuals, including bank staff. The objective of this study was to investigate the awareness of food nutritive value and eating practices among bank workers in Lagos State, Nigeria. The study adopted a cross-sectional descriptive survey design. A purposive sample of 250 bank workers took part in the study. Means and Student t tests were employed for data analysis. Results showed that bank workers were aware of the nutritive value of foods, and that eating practices commonly adopted included skipping breakfast, eating breakfast at work, buying food at work from the bank canteen, eating in between meals, buying snacks as lunch, and consuming soft drinks daily, among others. There were no significant differences between male and female bank workers in mean responses on food nutritive value or in eating practices adopted. Good eating habits will help bank workers not only to improve their nutritional well-being, but also to prevent nutrition-related diseases. The implications for nutritional counseling and education are discussed in the context of these findings. PMID:28272248

  7. Frequent summer nuptial flights of ants provide a primary food source for bats.

    PubMed

    Levin, Eran; Yom-Tov, Yoram; Barnea, Anat

    2009-04-01

    In many ant species, nuptial flight tends to be short in time and assumed to be synchronous across a large area. Here, we report that, in the upper Jordan Valley, northern Israel, massive nuptial flights of Carpenter ants (Camponotus sp.) occur frequently throughout the summer, and their alates form up to 90% of the diet of the greater mouse-tailed bat (Rhinopoma microphyllum) during this period. This fat and protein-rich diet enables female bats to lactate during summer, and the large amount of fat that both sexes accumulate may serve as an energy source for their following winter hibernation and posthibernation mating in early spring (March-April). We suggest that the annual movement of these bats to the Mediterranean region of Israel may have evolved in order to enable them to exploit the extremely nutritious forms of ant alates when the bats' energetic demands are highest.

  8. Frequent summer nuptial flights of ants provide a primary food source for bats

    NASA Astrophysics Data System (ADS)

    Levin, Eran; Yom-Tov, Yoram; Barnea, Anat

    2009-04-01

    In many ant species, nuptial flight tends to be short in time and assumed to be synchronous across a large area. Here, we report that, in the upper Jordan Valley, northern Israel, massive nuptial flights of Carpenter ants ( Camponotus sp.) occur frequently throughout the summer, and their alates form up to 90% of the diet of the greater mouse-tailed bat ( Rhinopoma microphyllum) during this period. This fat and protein-rich diet enables female bats to lactate during summer, and the large amount of fat that both sexes accumulate may serve as an energy source for their following winter hibernation and posthibernation mating in early spring (March-April). We suggest that the annual movement of these bats to the Mediterranean region of Israel may have evolved in order to enable them to exploit the extremely nutritious forms of ant alates when the bats’ energetic demands are highest.

  9. Mandibular gland secretions of meliponine worker bees: further evidence for their role in interspecific and intraspecific defence and aggression and against their role in food source signalling.

    PubMed

    Schorkopf, Dirk Louis P; Hrncir, Michael; Mateus, Sidnei; Zucchi, Ronaldo; Schmidt, Veronika M; Barth, Friedrich G

    2009-04-01

    Like ants and termites some species of stingless bees (Meliponini), which are very important pollinators in the tropics, use pheromone trails to communicate the location of a food source. We present data on the communicative role of mandibular gland secretions of Meliponini that resolve a recent controversy about their importance in the laying of such trails. Volatile constituents of the mandibular glands have been erroneously thought both to elicit aggressive/defensive behaviour and to signal food source location. We studied Trigona spinipes and Scaptotrigona aff. depilis ('postica'), two sympatric species to which this hypothesis was applied. Using extracts of carefully dissected glands instead of crude cephalic extracts we analysed the substances contained in the mandibular glands of worker bees. Major components of the extracts were 2-heptanol (both species), nonanal (T. spinipes), benzaldehyde and 2-tridecanone (S. aff. depilis). The effect of mandibular gland extracts and of individual components thereof on the behaviour of worker bees near their nest and at highly profitable food sources was consistent. Independent of the amount of mandibular gland extract applied, the bees overwhelmingly reacted with defensive behaviour and were never attracted to feeders scented with mandibular gland extract or any of the synthetic chemicals tested. Both bee species are capable of using mandibular gland secretions for intra- and interspecific communication of defence and aggression and share 2-heptanol as a major pheromone compound. While confirming the role of the mandibular glands in nest defence, our experiments provide strong evidence against their role in food source signalling.

  10. Usefulness of fire ant genetics in insecticide efficacy trials

    USDA-ARS?s Scientific Manuscript database

    Mature fire ant colonies contain an average of 80,000 worker ants. For this study, eight fire ant workers were randomly sampled from each colony. DNA fingerprints for each individual ant were generated using 21 simple sequence repeats (SSR) markers that were developed from fire ant DNA by other lab...

  11. Prey Capture Behavior in an Arboreal African Ponerine Ant

    PubMed Central

    Dejean, Alain

    2011-01-01

    I studied the predatory behavior of Platythyrea conradti, an arboreal ponerine ant, whereas most species in this subfamily are ground-dwelling. The workers, which hunt solitarily only around dusk, are able to capture a wide range of prey, including termites and agile, nocturnal insects as well as diurnal insects that are inactive at that moment of the Nyctemeron, resting on tree branches or under leaves. Prey are captured very rapidly, and the antennal palpation used by ground-dwelling ponerine species is reduced to a simple contact; stinging occurs immediately thereafter. The venom has an instant, violent effect as even large prey (up to 30 times the weight of a worker) never struggled after being stung. Only small prey are not stung. Workers retrieve their prey, even large items, singly. To capture termite workers and soldiers defending their nest entrances, ant workers crouch and fold their antennae backward. In their role as guards, the termites face the crouching ants and end up by rolling onto their backs, their legs batting the air. This is likely due to volatile secretions produced by the ants' mandibular gland. The same behavior is used against competing ants, including territorially-dominant arboreal species that retreat further and further away, so that the P. conradti finally drive them from large, sugary food sources. PMID:21589941

  12. Food-plant niche selection rather than the presence of ant nests explains oviposition patterns in the myrmecophilous butterfly genus Maculinea.

    PubMed Central

    Thomas, J. A.; Elmes, G. W.

    2001-01-01

    It has been suggested that the socially parasitic butterfly Maculinea alcon detects ant odours before ovipositing on initial larval food plants near colonies of its obligate ant host Myrmica ruginodis. It has also been suggested that overcrowding on food plants near M. ruginodis is avoided by an ability to detect high egg loads, resulting in a switch to selecting plants near less suitable ant species. If confirmed, this hypothesis (H1) would have serious implications for the application of current population models aimed at the conservation of endangered Maculinea species, which are based on the null hypothesis (H0) that females randomly select food plants whose flower buds are at a precise phenological stage, making oviposition independent of ants. If H1 were wrong, practical management based upon its assumptions could lead to the extinction of protected populations. We present data for the five European species of Maculinea which show that (i) each oviposits on a phenologically restricted flower-bud stage, which accounts for the apparent host-ant-mediated niche separation in sympatric populations of Maculinea nausithous and Maculinea teleius, (ii) there is no temporal shift in oviposition by Maculinea arion in relation to host ant distribution or egg density, and (iii) oviposition patterns in 13 populations of M. alcon's closest relative, Macaulinea rebeli, conform to H0 not H1 predictions. It is concluded that conservation measures should continue to be based on H0. PMID:11296858

  13. Food-plant niche selection rather than the presence of ant nests explains oviposition patterns in the myrmecophilous butterfly genus Maculinea.

    PubMed

    Thomas, J A; Elmes, G W

    2001-03-07

    It has been suggested that the socially parasitic butterfly Maculinea alcon detects ant odours before ovipositing on initial larval food plants near colonies of its obligate ant host Myrmica ruginodis. It has also been suggested that overcrowding on food plants near M. ruginodis is avoided by an ability to detect high egg loads, resulting in a switch to selecting plants near less suitable ant species. If confirmed, this hypothesis (H1) would have serious implications for the application of current population models aimed at the conservation of endangered Maculinea species, which are based on the null hypothesis (H0) that females randomly select food plants whose flower buds are at a precise phenological stage, making oviposition independent of ants. If H1 were wrong, practical management based upon its assumptions could lead to the extinction of protected populations. We present data for the five European species of Maculinea which show that (i) each oviposits on a phenologically restricted flower-bud stage, which accounts for the apparent host-ant-mediated niche separation in sympatric populations of Maculinea nausithous and Maculinea teleius, (ii) there is no temporal shift in oviposition by Maculinea arion in relation to host ant distribution or egg density, and (iii) oviposition patterns in 13 populations of M. alcon's closest relative, Macaulinea rebeli, conform to H0 not H1 predictions. It is concluded that conservation measures should continue to be based on H0.

  14. Factors influencing workers to follow food safety management systems in meat plants in Ontario, Canada.

    PubMed

    Ball, Brita; Wilcock, Anne; Aung, May

    2009-06-01

    Small and medium sized food businesses have been slow to adopt food safety management systems (FSMSs) such as good manufacturing practices and Hazard Analysis Critical Control Point (HACCP). This study identifies factors influencing workers in their implementation of food safety practices in small and medium meat processing establishments in Ontario, Canada. A qualitative approach was used to explore in-plant factors that influence the implementation of FSMSs. Thirteen in-depth interviews in five meat plants and two focus group interviews were conducted. These generated 219 pages of verbatim transcripts which were analysed using NVivo 7 software. Main themes identified in the data related to production systems, organisational characteristics and employee characteristics. A socio-psychological model based on the theory of planned behaviour is proposed to describe how these themes and underlying sub-themes relate to FSMS implementation. Addressing the various factors that influence production workers is expected to enhance FSMS implementation and increase food safety.

  15. Factors affecting the musculoskeletal disorders of workers in the frozen food manufacturing factories in Thailand.

    PubMed

    Thetkathuek, Anamai; Meepradit, Parvena; Jaidee, Wanlop

    2016-01-01

    The purpose of this research was to study factors affecting musculoskeletal disorders. The sample population of the study was 528 factory workers from the frozen food industry, as well as a controlled group of 255 office workers. The samples were collected during interviews using the Nordic questionnaire to assess musculoskeletal disorders, and to assess the risk by the rapid upper limb assessment and rapid entire body assessment techniques. The findings of the study were that most symptoms were found in the dissecting department, higher than in the controlled group. The details of the symptoms were, accordingly: elbow pain (adjusted odds ratio, 35.1; 95% CI [17.4, 70.9]). Regarding the risk of alcohol drinking, workers were exposed to more risks when alcohol was consumed. It is suggested that workers' health should be monitored regularly. People who work in a cold environment should be encouraged to wear body protection and to avoid drinking.

  16. Alate susceptibility in ants

    PubMed Central

    Ho, Eddie K H; Frederickson, Megan E

    2014-01-01

    Pathogens are predicted to pose a particular threat to eusocial insects because infections can spread rapidly in colonies with high densities of closely related individuals. In ants, there are two major castes: workers and reproductives. Sterile workers receive no direct benefit from investing in immunity, but can gain indirect fitness benefits if their immunity aids the survival of their fertile siblings. Virgin reproductives (alates), on the other hand, may be able to increase their investment in reproduction, rather than in immunity, because of the protection they receive from workers. Thus, we expect colonies to have highly immune workers, but relatively more susceptible alates. We examined the survival of workers, gynes, and males of nine ant species collected in Peru and Canada when exposed to the entomopathogenic fungus Beauveria bassiana. For the seven species in which treatment with B. bassiana increased ant mortality relative to controls, we found workers were significantly less susceptible compared with both alate sexes. Female and male alates did not differ significantly in their immunocompetence. Our results suggest that, as with other nonreproductive tasks in ant colonies like foraging and nest maintenance, workers have primary responsibility for colony immunity, allowing alates to specialize on reproduction. We highlight the importance of colony-level selection on individual immunity in ants and other eusocial organisms. PMID:25540683

  17. Worker lifespan is an adaptive trait during colony establishment in the long-lived ant Lasius niger.

    PubMed

    Kramer, Boris H; Schaible, Ralf; Scheuerlein, Alexander

    2016-12-01

    Eusociality has been recognized as a strong driver of lifespan evolution. While queens show extraordinary lifespans of 20years and more, worker lifespan is short and variable. A recent comparative study found that in eusocial species with larger average colony sizes the disparities in the lifespans of the queen and the worker are also greater, which suggests that lifespan might be an evolved trait. Here, we tested whether the same pattern holds during colony establishment: as colonies grow larger, worker lifespan should decrease. We studied the mortality of lab-reared Lasius niger workers from colonies at two different developmental stages (small and intermediate-sized) in a common garden experiment. Workers were kept in artificial cohorts that differed only with respect to the stage of the colony they were born in. We found that the stage of the birth colony affected the body size and the survival probability of the workers. The workers that had emerged from early stage colonies were smaller and had lower mortality during the first 400days of their life than the workers born in colonies at a later stage. Our results suggest that early stage colonies produce small workers with an increased survival probability. These workers are gradually augmented by larger workers with a decreased survival probability that serve as a redundant workforce with easily replaceable individuals. We doubt that the observed differences in lifespan are driven by differences in body size. Rather, we suspect that physiological mechanisms are the basis for the observed differences in lifespan. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Effect of gland extracts on digging and residing preferences of red imported fire ant workers (Hymenoptera: formicidae)

    USDA-ARS?s Scientific Manuscript database

    There was evidence that ant-derived chemical stimuli were involved in regulating the digging behavior in Solenopsis invicta Buren. Unfortunately however, the source gland(s) and chemistry of such stimuli have never been revealed. In this study, extracts of mandibular, Dufour, postpharyngeal and po...

  19. How Load-Carrying Ants Avoid Falling Over: Mechanical Stability during Foraging in Atta vollenweideri Grass-Cutting Ants

    PubMed Central

    Moll, Karin; Roces, Flavio; Federle, Walter

    2013-01-01

    Background Foraging workers of grass-cutting ants (Atta vollenweideri) regularly carry grass fragments larger than their own body. Fragment length has been shown to influence the ants’ running speed and thereby the colony’s food intake rate. We investigated whether and how grass-cutting ants maintain stability when carrying fragments of two different lengths but identical mass. Principal Findings Ants carried all fragments in an upright, backwards-tilted position, but held long fragments more vertically than short ones. All carrying ants used an alternating tripod gait, where mechanical stability was increased by overlapping stance phases of consecutive steps. The overlap was greatest for ants carrying long fragments, resulting in more legs contacting the ground simultaneously. For all ants, the projection of the total centre of mass (ant and fragment) was often outside the supporting tripod, i.e. the three feet that would be in stance for a non-overlapping tripod gait. Stability was only achieved through additional legs in ground contact. Tripod stability (quantified as the minimum distance of the centre of mass to the edge of the supporting tripod) was significantly smaller for ants with long fragments. Here, tripod stability was lowest at the beginning of each step, when the center of mass was near the posterior margin of the supporting tripod. By contrast, tripod stability was lowest at the end of each step for ants carrying short fragments. Consistently, ants with long fragments mainly fell backwards, whereas ants carrying short fragments mainly fell forwards or to the side. Assuming that transporting ants adjust neither the fragment angle nor the gait, they would be less stable and more likely to fall over. Conclusions In grass-cutting ants, the need to maintain static stability when carrying long grass fragments has led to multiple kinematic adjustments at the expense of a reduced material transport rate. PMID:23300994

  20. Food Insecurity Increases HIV Risk Among Young Sex Workers in Metro Vancouver, Canada.

    PubMed

    Barreto, Daniella; Shannon, Kate; Taylor, Chrissy; Dobrer, Sabina; Jean, Jessica St; Goldenberg, Shira M; Duff, Putu; Deering, Kathleen N

    2017-03-01

    This research aimed to determine the effect of food insecurity on sexual HIV risk with clients among youth sex workers (YSWs) <30 years in Metro Vancouver, Canada. Data were drawn from a prospective community cohort of sex workers (2010-2013). We examined the independent relationship between YSWs' food insecurity and being pressured into sex without a condom by clients ("client condom refusal"). Of 220 YSWs, 34.5 % (n = 76) reported client condom refusal over the 3.5-year study period and 76.4 % (n = 168) reported any food insecurity. Adjusting for other HIV risk pathways, food insecurity retained an independent effect on client condom refusal (AOR 2.08, 95 % CI 1.23-3.51), suggesting that food insecurity is significantly associated with HIV risk among YSWs. This study indicates a critical relationship between food insecurity and HIV risk, and demonstrates YSWs' particular vulnerability. Public policies for food assistance as a harm reduction measure may be key to addressing this disparity.

  1. Trail pheromone disruption of red imported fire ant.

    PubMed

    Suckling, David M; Stringer, Lloyd D; Bunn, Barry; El-Sayed, Ashraf M; Vander Meer, Robert K

    2010-07-01

    The fire ant, Solenopsis invicta (Hymenoptera: Formicidae), is considered one of the most aggressive and invasive species in the world. Toxic bait systems are used widely for control, but they also affect non-target ant species and cannot be used in sensitive ecosystems such as organic farms and national parks. The fire ant uses recruitment pheromones to organize the retrieval of large food resources back to the colony, with Z,E-alpha-farnesene responsible for the orientation of workers along trails. We prepared Z,E-alpha-farnesene, (91% purity) from extracted E,E-alpha-farnesene and demonstrated disruption of worker trail orientation after presentation of an oversupply of this compound from filter paper point sources (30 microg). Trails were established between queen-right colony cells and food sources in plastic tubs. Trail-following behavior was recorded by overhead webcam, and ants were digitized before and after presentation of the treatment, using two software approaches. The linear regression statistic, r(2) was calculated. Ants initially showed high linear trail integrity (r(2) = 0.75). Within seconds of presentation of the Z,E-alpha-farnesene treatment, the trailing ants showed little or no further evidence of trail following behavior in the vicinity of the pheromone source. These results show that trailing fire ants become disorientated in the presence of large amounts of Z,E-alpha-farnesene. Disrupting fire ant recruitment to resources may have a negative effect on colony size or other effects yet to be determined. This phenomenon was demonstrated recently for the Argentine ant, where trails were disrupted for two weeks by using their formulated trail pheromone, Z-9-hexadecenal. Further research is needed to establish the long term effects and control potential for trail disruption in S. invicta.

  2. US acculturation, food intake, and obesity among Asian-Pacific hotel workers.

    PubMed

    Novotny, Rachel; Williams, Andrew E; Vinoya, Aleli C; Oshiro, Caryn E S; Vogt, Thomas M

    2009-10-01

    Both obesity and immigration continue to increase in the United States. Studies suggest that a transition in lifestyle patterns, such as food intake, may mediate the relationship between immigration and obesity. We examine obesity among hotel workers in relation to age, sex, race/ethnicity, and indicators of food intake, immigration, and acculturation. Four thousand five hundred thirty hotel workers in 30 hotels were studied from the first year of the Work, Weight and Wellness program, before intervention (during 2005-2006). Weight and height were measured, whereas race/ethnicity, language, education, immigration, acculturation, and food intake variables were assessed by questionnaire. The study included 43% male and 57% female hotel workers (mean age 44.4+/-11.3 years; 42% Filipino, 32% other Asian, 13% Pacific Islander, 9% white, 1% black/African American, and 3% other race/ethnicity). On average (mean value), 55% of participants were born outside the United States; 57% were overweight or obese (body mass index [BMI] >25). The BMI of those born in the United States was 1.3 higher than that of those born in another country, adjusting for sex and race/ethnicity. Intake of sweet drinks and meat was positively associated with BMI while intake of fruit was negatively associated with BMI. Age at arrival in United States ("generation") was negatively associated with BMI, whereas greater acculturation was positively associated with BMI. Food intake behaviors are probably related to place of birth, generation of migration to the United States, and acculturation. Direct measures of food intake added explanatory power to models, suggesting the importance of food intake to obesity. Further study of the influence of immigration, acculturation, and food intake on obesity using longitudinal study designs is warranted.

  3. Nutrition and interference competition have interactive effects on the behavior and performance of Argentine ants.

    PubMed

    Kay, Adam D; Zumbusch, Taylor; Heinen, Justa L; Marsh, Tom C; Holway, David A

    2010-01-01

    Food availability often influences competitive outcomes through effects on consumer growth. Although it has received less attention, food availability may also affect competition through nutritional effects on behavior. One hypothesis linking nutrition and competition in ants posits that increased access to carbohydrates favors greater investment in worker traits that underlie behavioral dominance. We tested this hypothesis by varying dietary protein:carbohydrate (P:C) ratios and levels of interspecific interference for Argentine ants (Linepithema humile), a widespread invasive species. As predicted, colonies facing interference increased patrolling more when reared on low P:C diets; this result is the first demonstration of an interactive effect of nutrition and interference on ant colonies. Several results suggest that this dietary effect on patrolling was due primarily to changes in colony size rather than worker behavior. Colonies on lower P:C diets had lower worker mortality and larger final colony sizes. Diet had little effect on per capita patrolling, and worker behavior in performance assays depended more on previous exposure to interference than on diet. Our findings indicate that dietary P:C ratios can influence Argentine ant performance in a competitive environment and suggest a mechanism by which monopolization of carbohydrate-rich resources can help invasive ants displace native ant competitors.

  4. Respiratory symptoms and bronchial responsiveness among cleaning and disinfecting workers in the food industry.

    PubMed

    Massin, N; Hecht, G; Ambroise, D; Héry, M; Toamain, J P; Hubert, G; Dorotte, M; Bianchi, B

    2007-02-01

    To measure the levels of exposure to nitrogen trichloride (NCl3) and aldehydes among cleaning and disinfecting workers in the atmosphere of food industry plants during cleaning and disinfecting operations, and to examine how they relate to irritant and chronic respiratory symptoms-which are indices of pulmonary function-and bronchial hyperresponsiveness (BHR) to methacholine. 175 exposed workers (M = 149; F = 26) recruited from 17 enterprises of the food industry (8 cattle, pig, and ovine slaughterhouses, 8 fowl slaughterhouses, and 1 catering firm) and 70 non-exposed workers (M = 52; F = 18) were examined. Concentration levels of NCl3 and aldhehydes were measured by personal sampling. Symptoms were assessed by means of a questionnaire and the methacholine bronchial challenge (MBC) test using an abbreviated method. Subjects were labelled MBC+ if forced expiratory volume in one second (FEV1) fell by 20% or more. The linear dose-response slope (DRS) was calculated as the percentage fall in FEV1 at last dose divided by the total dose administered. 277 air samples were taken in the 17 food industry plants. For a given plant and in a given workshop, the actual concentrations of chloramines, aldehydes, and quaternary ammonium compounds were measured with personal samplers during the different steps of the procedures. For each cleaner, a total exposure index Sigma was calculated. A statistically significant concentration-response relationship was found between eye, nasal, and throat symptoms of irritation--but not chronic respiratory symptoms--and exposure levels or exposure duration. No relation was found between BHR and exposure. These data show that cleaning and disinfecting workers in the food industry are at risk of developing eye, nasal, and throat irritation symptoms. Although NCl3 exposure does not seem to carry a risk of developing permanent BHR, the possibility of transient BHR cannot be ruled out entirely.

  5. Food habits and nutritional status of agricultural migrant workers in Southern Brazil.

    PubMed

    Desai, I D; Garcia Tavares, M L; Dutra de Oliveira, B S; Douglas, A; Duarte, F A; Dutra de Oliveira, J E

    1980-03-01

    A new class of migrant workers, commonly known as "Boia-Frias", is rapidly growing in the periurban slumbs (favelas) of Brazil. In 1978 a collaborative study was undertaken to assess the food habits and nutritional status of 100 migrant worker families of Vila Recreio, a typical Boia-Fria settlement near Ribeirao Preto in the state of Sao Paulo. The findings of this survey revealed that the traditional diet of Boia-Frias is nutritionally inadequate both in quality and quantity. Their rice and bean-based diet lacks sufficient variety because of the infrequent use of fresh fruits and vegetables, which are available locally, and of supplemental amounts of protein-rich foods of animal origin. Empty-calorie foods such as carbonated drinks and alcoholic beverages are consumed freely; and starchy foods, traditionally used in the North and Northeast of Brazil, are used commonly as weaning foods. Although dietary practices of pregnant and lactating women are poor, breast-feeding is still practiced by most mothers. The biochemical analysis of blood samples did not indicate major subclinical deficiencies except low hematological values and low plasma vitamin A concentrations in about 25% of the population examined. Plasma cholesterol and plasma vitamin E values were found to be normal. However, anthropometric examinations revealed clear signs of malnutrition and/or undernourishment, which likely impairs their capacity for physical work and adversely affects their overall health.

  6. Salmonella infections in food workers identified through routine Public Health Surveillance in Minnesota: impact on outbreak recognition.

    PubMed

    Medus, Carlota; Smith, Kirk E; Bender, Jeffrey B; Leano, Fe; Hedberg, Craig W

    2010-11-01

    The frequency of Salmonella-infected food workers identified through routine surveillance from 1997 to 2004 in Minnesota was determined in order to evaluate the impact of surveillance on the detection of outbreaks in restaurants and to quantify the duration of Salmonella shedding in stool. Of 4,976 culture-confirmed Salmonella cases reported to the Minnesota Department of Health, 110 (2.2%) were identified as food workers; this was less than one-half the number expected based on the incidence of Salmonella in the general population. Twenty food workers (18%) were associated with outbreaks. Twelve were involved in nine independent outbreaks at the restaurants where they worked. The identification of the index food worker in six of these outbreaks was critical to the initiation of outbreak investigations that revealed much larger problems. Among food workers who submitted specimens until at least one negative result was obtained (n = 69), the median duration of shedding was 22 days (range, 1 to 359 days). Among the four most common serotypes (Enteritidis, Typhimurium, Heidelberg, and Newport) the median duration of shedding was significantly longer for Salmonella Newport (80 days; P = 0.02) and for Salmonella Enteritidis (32 days; P = 0.04) than for Salmonella Heidelberg (8 days). Food workers should be considered an important source of Salmonella transmission, and those identified through surveillance should raise a high index of suspicion of a possible outbreak at their place of work. Food service managers need to be alert to Salmonella-like illnesses among food workers to facilitate prevention and control efforts, including exclusion of infected food workers or restriction of their duties.

  7. The re-discovered Maculinea rebeli (Hirschke, 1904): Host ant usage, parasitoid and initial food plant around the type locality with taxonomical aspects (Lepidoptera, Lycaenidae).

    PubMed

    Tartally, András; Koschuh, Anton; Varga, Zoltán

    2014-01-01

    The taxonomy of the myrmecophilous Maculinea alcon group (Lepidoptera: Lycaenidae) is highly debated. The host-plant and host-ant usage of these butterflies have conventionally been important in their identification. Maculinea 'rebeli' has generally been considered to be the xerophilous form of Ma. alcon (Ma. alcon X hereafter) with Gentiana cruciata as initial food plant. However, the type locality and all other known sites of Ma. rebeli are found above the coniferous zone, and are well separated from the lower regions where Ma. alcon X sites are found. Furthermore, no food plant and host ant data for the nominotypic Ma. rebeli have yet been published. Our aim was therefore to identify the host ant(s) of Ma. rebeli around the type locality and compare this with the host ant usage of nearby Ma. alcon X. Nests of Myrmica spp. (Hymenoptera: Formicidae) close to the host plants were opened on one Ma. alcon X (host plant: Gentiana cruciata) and two Ma. rebeli (host plant: Gentianella rhaetica, first record, confirmed by oviposition and emerging larvae) sites just before the flying period, to find prepupal larvae and pupae. Three Myrmica species (My. lobulicornis, My. ruginodis, My. sulcinodis) were found on the two Ma. rebeli sites, which parasitized exclusively My. sulcinodis (22 individuals in 7 nests). On the Ma. alcon X site Myrmica sabuleti and My. lonae were found, with My. sabuleti the exclusive host (51 individuals in 10 nests). Ichneumon cf. eumerus parasitized both butterflies. The results highlight the differentiation of Maculinea rebeli from Ma. alcon X, from both conservation biological and ecological points of view. Thus, it should be concluded that Ma. rebeli does not simply represent an individual form of Ma. alcon but it can be considered as at least an ecological form adapted to high mountain conditions both in its initial food plant and host ant species. In addition, it should be emphasized that Ma. alcon X (= Ma. rebeli auct. nec Hirschke) cannot be

  8. Timekeeping through social contacts: social synchronization of circadian locomotor activity rhythm in the carpenter ant Camponotus paria.

    PubMed

    Lone, Shahnaz Rahman; Sharma, Vijay Kumar

    2011-12-01

    In ant colonies a large proportion of individuals remain inside nests for most of their lives and come out only when necessary. It is not clear how, in a nest of several thousand individuals, information about local time is communicated among members of the colony. Central to this seem to be circadian clocks, which have an intrinsic ability to keep track of local time by entraining to environmental light-dark, temperature, and social cycles. Here, the authors report the results of their study aimed at understanding the role of cyclic social interactions in circadian timekeeping of a day-active species of carpenter ant Camponotus paria. The authors found that daily social interactions with visitors (worker ants) was able to synchronize the circadian locomotor activity rhythm of host worker ants and queens, in one-on-one (pair-wise) and multi-individual (group-wise) interactions. Interestingly, the outcome of cyclic social interactions was context specific; when visitor workers socially interacted with host workers one-on-one, host workers considered the time of interaction as subjective day, but when visitor workers interacted with a group of workers and queens, the hosts considered the time of interaction as subjective night. These results can be taken to suggest that members of the ant species C. paria keep track of local time by socially interacting with workers (foragers) who shuttle in and out of the colony in search of food. (Author correspondence: vsharma@jncasr.ac.in ).

  9. Cold Exposure and Health Effects Among Frozen Food Processing Workers in Eastern Thailand

    PubMed Central

    Thetkathuek, Anamai; Yingratanasuk, Tanongsak; Jaidee, Wanlop; Ekburanawat, Wiwat

    2014-01-01

    Frozen food processing workers work under a cold environment which can cause several adverse health effects.This study explored factors affecting workers' health in the frozen food industry in Thailand. Participants comprised 497 workers exposed to a cold working environment and 255 office workers who served as the controls. Data were collected by a survey on the work environment, and the interview of workers for abnormal symptoms. The exposed group had the following characteristics: 52.7% male, overall average age of 27 (SD 6.6) years old, attained elementary education (Grade 4 and Grade 6) (54.1%), married (48.9%), smokers (21.3%), alcohol consumption (31.0%), duration of work was between 1 and 5 years (65.2%), working 6 days a week (82.7%), 1–5 hours of overtime per week (33.8%), office workers (33.9%); work category: sizing (6.9%), peeling (28.3%) dissecting (22.2%), and in the warehouse (8.6%). The temperature in the work environment ranged from 17.2°C to 19.2°C in most sections, −18.0°C in the warehouse, and 25°C in the office areas. Warehouse workers had more abnormal symptoms than controls including repeated pain in the musculoskeletal system (OR 11.9; 95% CI 6.12–23.45), disturbance throughout the body (OR 4.60; 95% CI 2.00–10.56), respiratory symptoms (OR 9.73; 95% CI 3.53–26.80), episodic finger symptoms (OR 13.51; 95% CI 5.17–35.33). The study results suggest that workers' health should be monitored especially with regard to back and muscle pain, respiratory symptoms, episodic finger symptoms, and cardiovascular symptoms. Health promotion campaigns such as antismoking and reduction of alcohol consumption should be established because smoking and alcohol consumption are contributing factors to the pathogenesis of Raynaud's phenomenon and peripheral vascular disorders such as hypertension and heart disease. PMID:25830071

  10. Restaurant Salmonella Enteritidis outbreak associated with an asymptomatic infected food worker.

    PubMed

    Hedican, Erin; Hooker, Carol; Jenkins, Timothy; Medus, Carlota; Jawahir, Selina; Leano, Fe; Smith, Kirk

    2009-11-01

    Salmonella is the most common bacterial cause of foodborne outbreaks in the United States; approximately half of Salmonella outbreaks occur in restaurant settings. In February 2008, investigation of a cluster of Salmonella Enteritidis cases with indistinguishable pulsed-field gel electrophoresis (PFGE) patterns revealed that five cases had eaten at the same restaurant. Cases were identified through routine surveillance activities and by contacting meal companions of culture-confirmed cases. Well meal companions and well patrons contacted via check stubs served as controls. Illness histories and stool samples were collected from all restaurant employees. Sandwiches were the only menu item or ingredient significantly associated with illness (15 of 15 cases versus 17 of 37 controls; odds ratio, undefined; P < 0.001). None of the six restaurant employees reported experiencing recent gastrointestinal symptoms. The outbreak PFGE subtype of Salmonella Enteritidis was identified in two food workers. One of the positive employees began working at the restaurant shortly before the first exposure date reported by a case, and assisted in the preparation of sandwiches and other foods consumed by cases. The other positive employee rarely, if ever, handled food. The restaurant did not have a glove use policy. There was no evidence of ongoing transmission after exclusion of the positive food workers. This was a restaurant Salmonella Enteritidis outbreak associated with an asymptomatic infected food worker. Routine PFGE subtyping of Salmonella Enteritidis isolates, routine interviewing of cases, and an iterative approach to cluster investigations allowed for timely identification of the source of an outbreak of Salmonella Enteritidis infections.

  11. Foraging activity and dietary spectrum of the Argentine ant (Hymenoptera: Formicidae) in invaded natural areas of the northeast Iberian Peninsula.

    PubMed

    Abril, S; Oliveras, J; Gómez, C

    2007-10-01

    We analyzed the foraging activity and the dietary spectrum of the Argentine ant (Linepithema humile Mayr) and select native ants on cork oaks from Mediterranean open cork oak (Quercus suber) secondary forests. The study areas included invaded and noninvaded zones in close proximity. The Argentine ant's daily foraging activity was correlated to the abiotic factors studied, whereas the seasonal foraging activity was related not only to the variations in the average air temperature, but also to the trophic needs of the colony. Argentine ant workers focused their attention on protein foods during the queens' oviposition periods and during the larvae development phase, and on carbohydrate foods, such as honeydew, when males and workers were hatching. There were no significant differences over the entire year in the quantity of liquid food collected by the Argentine ant workers in comparison with the native ants studied. The solid diet of the Argentine ant on cork oaks is composed of insects, most of which are aphids. Our results have clear applications for control methods based on toxic baits in the invaded natural ecosystems of the Iberian Peninsula.

  12. Weeding and grooming of pathogens in agriculture by ants.

    PubMed

    Currie, C R; Stuart, A E

    2001-05-22

    The ancient mutualism between fungus-growing ants and the fungi they cultivate for food is a textbook example of symbiosis. Fungus-growing ants' ability to cultivate fungi depends on protection of the garden from the aggressive microbes associated with the substrate added to the garden as well as from the specialized virulent garden parasite Escovopsis. We examined ants' ability to remove alien microbes physically by infecting Atta colombica gardens with the generalist pathogen Trichoderma viride and the specialist pathogen Escovopsis. The ants sanitized the garden using two main behaviours: grooming of alien spores from the garden (fungus grooming) and removal of infected garden substrate (weeding). Unlike previously described hygienic behaviours (e.g. licking and self-grooming), fungus-grooming and garden-removal behaviours are specific responses to the presence of fungal pathogens. In the presence of pathogens, they are the primary activities performed by workers, but they are uncommon in uninfected gardens. In fact, workers rapidly eliminate Trichoderma from their gardens by fungus grooming and weeding, suggesting that these behaviours are the primary method of garden defence against generalist pathogens. The same sanitary behaviours were performed in response to the presence of the specialist pathogen Escovopsis. However, the intensity and duration of these behaviours were much greater in this treatment. Despite the increased effort, the ants were unable to eliminate Escovopsis from their gardens, suggesting that this specialized pathogen has evolved counter-adaptations in order to overcome the sanitary defences of the ants.

  13. Seasonal effects of food macronutrient content on ants: Colony and individual responses

    USDA-ARS?s Scientific Manuscript database

    Long-lived animals experience different conditions as seasons change. Associated with seasonality are shifts in food quality and abundance. Animals can respond to seasonality by modifying their foraging behavior and adjusting the manner in which they utilize and process ingested nutrients. This allo...

  14. Poverty and household food security of black South African farm workers: the legacy of social inequalities.

    PubMed

    Kruger, A; Lemke, S; Phometsi, Mars; Van't Riet, H; Pienaar, Ae; Kotze, G

    2006-10-01

    To assess socio-economic indicators, nutritional status and living conditions of farm workers and their families, with the purpose to develop research and intervention programmes aimed at enhancing nutritional status and quality of life. Three farm schools in two districts of the North-West Province and farming communities were selected. Anthropometrical measurements, structured face-to-face questionnaires and focus group discussions were carried out in 2002 and 2003 by a multidisciplinary research team. Access to electricity, water and sanitation, as well as monthly food rations or subsidies, vary and depend on farm owners. The majority of adults have education below or up to grade four, farm schools provide only up to grade seven. Distance to farm schools and intra-household issues hamper children's attendance and performance at school. Household food security is compromised due to a lack of financial resources, infrastructure and also household resource allocation. This impacts negatively especially on children, with half of them being underweight, stunted or wasted. Employment is usually linked to men, while most women have access to casual jobs only. Insecurity of residence and the perceived disempowered position towards farm owners add to feelings of hopelessness and stress. This study highlights destitute living conditions of farm worker families. Apart from structural and financial constraints, paternalistic structures of the past might also hamper development. Based on these findings, follow-up research projects and in-depth investigations into underlying social issues with regard to nutrition insecurity and livelihoods of farm workers were initiated.

  15. Specificity in the symbiotic association between fungus-growing ants and protective Pseudonocardia bacteria.

    PubMed

    Cafaro, Matías J; Poulsen, Michael; Little, Ainslie E F; Price, Shauna L; Gerardo, Nicole M; Wong, Bess; Stuart, Alison E; Larget, Bret; Abbot, Patrick; Currie, Cameron R

    2011-06-22

    Fungus-growing ants (tribe Attini) engage in a mutualism with a fungus that serves as the ants' primary food source, but successful fungus cultivation is threatened by microfungal parasites (genus Escovopsis). Actinobacteria (genus Pseudonocardia) associate with most of the phylogenetic diversity of fungus-growing ants; are typically maintained on the cuticle of workers; and infection experiments, bioassay challenges and chemical analyses support a role of Pseudonocardia in defence against Escovopsis through antibiotic production. Here we generate a two-gene phylogeny for Pseudonocardia associated with 124 fungus-growing ant colonies, evaluate patterns of ant-Pseudonocardia specificity and test Pseudonocardia antibiotic activity towards Escovopsis. We show that Pseudonocardia associated with fungus-growing ants are not monophyletic: the ants have acquired free-living strains over the evolutionary history of the association. Nevertheless, our analysis reveals a significant pattern of specificity between clades of Pseudonocardia and groups of related fungus-growing ants. Furthermore, antibiotic assays suggest that despite Escovopsis being generally susceptible to inhibition by diverse Actinobacteria, the ant-derived Pseudonocardia inhibit Escovopsis more strongly than they inhibit other fungi, and are better at inhibiting this pathogen than most environmental Pseudonocardia strains tested. Our findings support a model that many fungus-growing ants maintain specialized Pseudonocardia symbionts that help with garden defence.

  16. Honey Ants.

    ERIC Educational Resources Information Center

    Conway, John R.

    1984-01-01

    Provides background information on honey ants. These ants are found in dry or desert regions of North America, Africa, and Australia. Also provides a list of activities using local species of ants. (JN)

  17. Honey Ants.

    ERIC Educational Resources Information Center

    Conway, John R.

    1984-01-01

    Provides background information on honey ants. These ants are found in dry or desert regions of North America, Africa, and Australia. Also provides a list of activities using local species of ants. (JN)

  18. Use of Visuals for Food Safety Education of Spanish-Speaking Foodservice Workers: A Case Study in Iowa

    ERIC Educational Resources Information Center

    Rajagopal, Lakshman

    2012-01-01

    Providing food safety training to an audience whose native language is not English is always a challenge. In the study reported here, minimal-text visuals in Spanish were used to train Hispanic foodservice workers about proper handwashing technique and glove use based on the 2005 Food Code requirements. Overall, results indicated that visuals…

  19. Use of Visuals for Food Safety Education of Spanish-Speaking Foodservice Workers: A Case Study in Iowa

    ERIC Educational Resources Information Center

    Rajagopal, Lakshman

    2012-01-01

    Providing food safety training to an audience whose native language is not English is always a challenge. In the study reported here, minimal-text visuals in Spanish were used to train Hispanic foodservice workers about proper handwashing technique and glove use based on the 2005 Food Code requirements. Overall, results indicated that visuals…

  20. Trail Pheromone of the Argentine Ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae)

    PubMed Central

    Choe, Dong-Hwan; Villafuerte, David B.; Tsutsui, Neil D.

    2012-01-01

    The Argentine ant (Linepithema humile) is recognized as one of the world's most damaging invasive species. One reason for the ecological dominance of introduced Argentine ant populations is their ability to dominate food and habitat resources through the rapid mobilization and recruitment of thousands of workers. More than 30 years ago, studies showed that (Z)-9-hexadecenal strongly attracted Argentine ant workers in a multi-choice olfactometer, suggesting that (Z)-9-hexadecenal might be the trail pheromone, or a component of a trail pheromone mixture. Since then, numerous studies have considered (Z)-9-hexadecenal as the key component of the Argentine ant trails. Here, we report the first chemical analyses of the trails laid by living Argentine ants and find that (Z)-9-hexadecenal is not present in a detectible quantity. Instead, two iridoids, dolichodial and iridomyrmecin, appear to be the primary chemical constituents of the trails. Laboratory choice tests confirmed that Argentine ants were attracted to artificial trails comprised of these two chemicals significantly more often than control trails. Although (Z)-9-hexadecenal was not detected in natural trails, supplementation of artificial dolichodial+iridomyrmecin trails with an extremely low concentraion of (Z)-9-hexadecenal did increase the efficacy of the trail-following behavior. In stark contrast with previous dogma, our study suggests that dolichodial and iridomyrmecin are major components of the Argentine ant trail pheromone. (Z)-9-hexadecenal may act in an additive manner with these iridoids, but it does not occur in detectable quantities in Argentine ant recruitment trails. PMID:23028739

  1. Trail pheromone of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae).

    PubMed

    Choe, Dong-Hwan; Villafuerte, David B; Tsutsui, Neil D

    2012-01-01

    The Argentine ant (Linepithema humile) is recognized as one of the world's most damaging invasive species. One reason for the ecological dominance of introduced Argentine ant populations is their ability to dominate food and habitat resources through the rapid mobilization and recruitment of thousands of workers. More than 30 years ago, studies showed that (Z)-9-hexadecenal strongly attracted Argentine ant workers in a multi-choice olfactometer, suggesting that (Z)-9-hexadecenal might be the trail pheromone, or a component of a trail pheromone mixture. Since then, numerous studies have considered (Z)-9-hexadecenal as the key component of the Argentine ant trails. Here, we report the first chemical analyses of the trails laid by living Argentine ants and find that (Z)-9-hexadecenal is not present in a detectible quantity. Instead, two iridoids, dolichodial and iridomyrmecin, appear to be the primary chemical constituents of the trails. Laboratory choice tests confirmed that Argentine ants were attracted to artificial trails comprised of these two chemicals significantly more often than control trails. Although (Z)-9-hexadecenal was not detected in natural trails, supplementation of artificial dolichodial+iridomyrmecin trails with an extremely low concentraion of (Z)-9-hexadecenal did increase the efficacy of the trail-following behavior. In stark contrast with previous dogma, our study suggests that dolichodial and iridomyrmecin are major components of the Argentine ant trail pheromone. (Z)-9-hexadecenal may act in an additive manner with these iridoids, but it does not occur in detectable quantities in Argentine ant recruitment trails.

  2. Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors.

    PubMed

    Keller, Roberto A; Peeters, Christian; Beldade, Patrícia

    2014-01-01

    The concerted evolution of morphological and behavioral specializations has compelling examples in ant castes. Unique to ants is a marked divergence between winged queens and wingless workers, but morphological specializations for behaviors on the ground have been overlooked. We analyzed thorax morphology of queens and workers in species from 21 of the 25 ant subfamilies. We uncovered unique skeletomuscular modifications in workers that presumably increase power and flexibility of head-thorax articulation, emphasizing that workers are not simply wingless versions of queens. We also identified two distinct types of queens and showed repeated evolutionary associations with strategies of colony foundation. Solitary founding queens that hunt have a more worker-like thorax. Our results reveal that ants invest in the relative size of thorax segments according to their tasks. Versatility of head movements allows for better manipulation of food and objects, which arguably contributed to the ants' ecological and evolutionary success. DOI: http://dx.doi.org/10.7554/eLife.01539.001.

  3. Insecticidal, fumigant, and repellent activities of sweet wormwood oil and its individual components against red imported fire ant workers (Hymenoptera: Formicidae).

    PubMed

    Zhang, Ning; Tang, Liang; Hu, Wei; Wang, Kun; Zhou, You; Li, Hong; Huang, Congling; Chun, Jiong; Zhang, Zhixiang

    2014-01-01

    In total, 29 compounds from sweet wormwood (Artemisia annua L.) oil were identified using gas chromatography-mass spectrometry. The five active components were D-camphor, linalool, cineole, α-terpineol, and L(-)-borneol. The effectiveness of A. annua oil, as well as d-camphor, linalool, cineole, α-terpineol, and L(-)-borneol, as fumigants, contact insecticides, and repellents, were tested on the red imported fire ant Solenopsis invicta Buren. The results indicated that A. annua oil has no significant topical toxicity; however, the spray contact test revealed that it has strong insecticidal activity and the inhibitory effect is stronger during closed exposure than during open exposure. In the fumigant test, cineole and D-camphor exhibited strong fumigant toxicity on minor and major S. invicta workers. They also caused 100% mortality at 5, 3, 2, and 1 mg/centrifuge tube but not at 0.5 mg/centrifuge tube. The mortality rates of linalool, α-terpineol, and L(-)-borneol exceeded 80% at 5, 3, and 2 mg/centrifuge tube. In the repellent test, cineole and d-camphor showed significant repellency at 100, 10, and 1 mg/kg. However, linalool, α-terpineol, and L(-)-borneol significantly facilitated digging at 10 and 1 mg/kg.

  4. 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

  5. The organization of foraging in the fire ant, Solenopsis invicta.

    PubMed

    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

  6. Prevalence and characterization of methicillin-resistant Staphylococcus aureus isolates in food industry workers.

    PubMed

    Caggiano, G; Dambrosio, A; Ioanna, F; Balbino, S; Barbuti, G; De Giglio, O; Diella, G; Lovero, G; Rutigliano, S; Scarafile, G; Baldassarre, A; Vimercati, L; Musti, M; Montagna, M T

    2016-01-01

    Methicillin-resistant S. aureus (MRSA) is a pathogen spread not only in the hospital environment but also in the community and amongst livestock (LA-MRSA). LA-MRSA can be transmitted to humans that live in close contact with MRSA-colonized animals, and human colonization and/or infection has been reported worldwide, particularly among those involved with livestock farming. In this study the authors evaluated the prevalence of S. aureus and MRSA among healthy carriers who worked in the food industry in Apulia, Southern Italy. Nasal swabs were taken from pasta and pork industry workers. All swab samples were subjected to tests for the isolation, identification and typing of S. aureus and MRSA strains. The identification of the strains was confirmed by molecular assessment using multiplex-PCR for the amplification of the nuc and mecA genes. The strains identified as MRSA were then subjected to a PCR protocol for the characterization of sequence type ST398. In total 26.3% of examined nasal swabs were positive for S. aureus, 8.2% of them were methicillin resistant strains and 28.5% of MRSA isolates were characterized as ST398. The MRSA prevalence among pork factory workers was 3% , whereas among the pasta operators the prevalence was 11.5. The presence of S. aureus and MRSA among food workers represents a public health risk. Further, considering the dissemination of S. aureus and MRSA among non-nosocomial environments, including communities and livestock, careful surveillance and continuous monitoring of the emergence of MRSA is fundamental for safeguarding public health.

  7. The re-discovered Maculinea rebeli (Hirschke, 1904): Host ant usage, parasitoid and initial food plant around the type locality with taxonomical aspects (Lepidoptera, Lycaenidae)

    PubMed Central

    Tartally, András; Koschuh, Anton; Varga, Zoltán

    2014-01-01

    Abstract The taxonomy of the myrmecophilous Maculinea alcon group (Lepidoptera: Lycaenidae) is highly debated. The host-plant and host-ant usage of these butterflies have conventionally been important in their identification. Maculinea ‘rebeli’ has generally been considered to be the xerophilous form of Ma. alcon (Ma. alcon X hereafter) with Gentiana cruciata as initial food plant. However, the type locality and all other known sites of Ma. rebeli are found above the coniferous zone, and are well separated from the lower regions where Ma. alcon X sites are found. Furthermore, no food plant and host ant data for the nominotypic Ma. rebeli have yet been published. Our aim was therefore to identify the host ant(s) of Ma. rebeli around the type locality and compare this with the host ant usage of nearby Ma. alcon X. Nests of Myrmica spp. (Hymenoptera: Formicidae) close to the host plants were opened on one Ma. alcon X (host plant: Gentiana cruciata) and two Ma. rebeli (host plant: Gentianella rhaetica, first record, confirmed by oviposition and emerging larvae) sites just before the flying period, to find prepupal larvae and pupae. Three Myrmica species (My. lobulicornis, My. ruginodis, My. sulcinodis) were found on the two Ma. rebeli sites, which parasitized exclusively My. sulcinodis (22 individuals in 7 nests). On the Ma. alcon X site Myrmica sabuleti and My. lonae were found, with My. sabuleti the exclusive host (51 individuals in 10 nests). Ichneumon cf. eumerus parasitized both butterflies. The results highlight the differentiation of Maculinea rebeli from Ma. alcon X, from both conservation biological and ecological points of view. Thus, it should be concluded that Ma. rebeli does not simply represent an individual form of Ma. alcon but it can be considered as at least an ecological form adapted to high mountain conditions both in its initial food plant and host ant species. In addition, it should be emphasized that Ma. alcon X (= Ma. rebeli auct. nec

  8. Coming out of the woods: do termites need a specialized worker caste to search for new food sources?

    NASA Astrophysics Data System (ADS)

    Rupf, Thomas; Roisin, Yves

    2008-09-01

    Most small-colony termites live confined within a single piece of wood on which they feed and do not possess permanent workers: Tasks are done by developmentally flexible immatures (pseudergates). By contrast, large-colony termites possess a specialized (true) worker caste and forage outside their nest for food. To shed light on possible transitional steps between these contrasting patterns of social organization, we studied an atypical Rhinotermitidae, Prorhinotermes inopinatus. In this species, despite the absence of a true worker caste, soldiers, pseudergates, and neotenic reproductives may leave the nest and explore their surroundings. Although evidence presented in this study indicates that termites recognize unknown areas, there is no directional recruitment toward them. The discovery of a food source, i.e., a piece of wood, is followed by the establishment of a long-lasting trail between the nest and the food source. A large fraction of the colony, including neotenic reproductives, ultimately migrates into the piece of wood. Our results thus demonstrate that multiple features of external foraging behavior can evolve independently of the existence of a true worker caste in termites. We suggest that large colonies with true workers, like those of most Rhinotermitidae, may easily have evolved from a Prorhinotermes-like pattern if submitted to increasing selective pressures for worker efficiency in a stable environment.

  9. Specificity in the symbiotic association between fungus-growing ants and protective Pseudonocardia bacteria

    PubMed Central

    Cafaro, Matías J.; Poulsen, Michael; Little, Ainslie E. F.; Price, Shauna L.; Gerardo, Nicole M.; Wong, Bess; Stuart, Alison E.; Larget, Bret; Abbot, Patrick; Currie, Cameron R.

    2011-01-01

    Fungus-growing ants (tribe Attini) engage in a mutualism with a fungus that serves as the ants' primary food source, but successful fungus cultivation is threatened by microfungal parasites (genus Escovopsis). Actinobacteria (genus Pseudonocardia) associate with most of the phylogenetic diversity of fungus-growing ants; are typically maintained on the cuticle of workers; and infection experiments, bioassay challenges and chemical analyses support a role of Pseudonocardia in defence against Escovopsis through antibiotic production. Here we generate a two-gene phylogeny for Pseudonocardia associated with 124 fungus-growing ant colonies, evaluate patterns of ant–Pseudonocardia specificity and test Pseudonocardia antibiotic activity towards Escovopsis. We show that Pseudonocardia associated with fungus-growing ants are not monophyletic: the ants have acquired free-living strains over the evolutionary history of the association. Nevertheless, our analysis reveals a significant pattern of specificity between clades of Pseudonocardia and groups of related fungus-growing ants. Furthermore, antibiotic assays suggest that despite Escovopsis being generally susceptible to inhibition by diverse Actinobacteria, the ant-derived Pseudonocardia inhibit Escovopsis more strongly than they inhibit other fungi, and are better at inhibiting this pathogen than most environmental Pseudonocardia strains tested. Our findings support a model that many fungus-growing ants maintain specialized Pseudonocardia symbionts that help with garden defence. PMID:21106596

  10. Awareness of food nutritive value and eating practices among Nigerian bank workers: Implications for nutritional counseling and education.

    PubMed

    Eze, Ngozi M; Maduabum, Felicia O; Onyeke, Nkechi G; Anyaegunam, Ngozi J; Ayogu, Chinwe A; Ezeanwu, Bibian Amaka; Eseadi, Chiedu

    2017-03-01

    Adequate nutrition is an important aspect of a healthy lifestyle for all individuals, including bank staff. The objective of this study was to investigate the awareness of food nutritive value and eating practices among bank workers in Lagos State, Nigeria.The study adopted a cross-sectional descriptive survey design. A purposive sample of 250 bank workers took part in the study. Means and Student t tests were employed for data analysis.Results showed that bank workers were aware of the nutritive value of foods, and that eating practices commonly adopted included skipping breakfast, eating breakfast at work, buying food at work from the bank canteen, eating in between meals, buying snacks as lunch, and consuming soft drinks daily, among others. There were no significant differences between male and female bank workers in mean responses on food nutritive value or in eating practices adopted.Good eating habits will help bank workers not only to improve their nutritional well-being, but also to prevent nutrition-related diseases. The implications for nutritional counseling and education are discussed in the context of these findings.

  11. Exploitation and interference competition between the invasive Argentine ant, Linepithema humile, and native ant species.

    PubMed

    Human, Kathleen G; Gordon, Deborah M

    1996-02-01

    Interactions between the invasive Argentine ant, Linepithema humile, and native ant species were studied in a 450-ha biological reserve in northern California. Along the edges of the invasion, the presence of Argentine ants significantly reduced the foraging success of native ant species, and vice versa. Argentine ants were consistently better than native ants at exploiting food sources: Argentine ants found and recruited to bait more consistently and in higher numbers than native ant species, and they foraged for longer periods throughout the day. Native ants and Argentine ants frequently fought when they recruited to the same bait, and native ant species were displaced from bait during 60% of these encounters. In introduction experiments, Argentine ants interfered with the foraging of native ant species, and prevented the establishment of new colonies of native ant species by preying upon winged native ant queens. The Argentine ants' range within the preserve expanded by 12 ha between May 1993 and May 1994, and 13 between September 1993 and September 1994, with a corresponding reduction of the range of native ant species. Although some native ants persist locally at the edges of the invasion of Argentine ants, most eventually disappear from invaded areas. Both interference and exploitation competition appear to be important in the displacement of native ant species from areas invaded by Argentine ants.

  12. Ant allergens and hypersensitivity reactions in response to ant stings.

    PubMed

    Potiwat, Rutcharin; Sitcharungsi, Raweerat

    2015-12-01

    Hypersensitivity reactions caused by ant stings are increasingly recognized as an important cause of death by anaphylaxis. Only some species of ants ( e.g. Solenopsis spp., Myrmecia spp., and Pachycondyla spp.) cause allergic reactions. Ant species are identified by evaluating the morphologic structures of worker ants or by molecular techniques. Ant venom contains substances, including acids and alkaloids, that cause toxic reactions, and those from Solenopsis invicta or the imported fire ant have been widely studied. Piperidine alkaloids and low protein contents can cause local reactions (sterile pustules) and systemic reactions (anaphylaxis). Imported fire ant venoms are cross-reactive; for example, the Sol i 1 allergen from S. invicta has cross-reactivity with yellow jacket phospholipase. The Sol i 3 allergen is a member of the antigen 5 family that has amino acid sequence identity with vespid antigen 5. The clinical presentations of ant hypersensitivity are categorized into immediate and delayed reactions: immediate reactions, such as small local reactions, large local reactions, and systemic reactions, occur within 1-4 hours after the ant stings, whereas delayed reactions, such as serum sickness and vasculitis, usually occur more than 4 hours after the stings. Tools for the diagnosis of ant hypersensitivity are skin testing, serum specific IgE, and sting challenge tests. Management of ant hypersensitivity can be divided into immediate (epinephrine, corticosteroids), symptomatic (antihistamines, bronchodilators), supportive (fluid resuscitation, oxygen therapy), and preventive (re-sting avoidance and immunotherapy) treatments.

  13. The Dynamics of Foraging Ants

    NASA Astrophysics Data System (ADS)

    Baxter, G. William

    2009-03-01

    We experimentally study the foraging of small black ants, Formicinae lasius flavus, in order to describe their foraging behavior mathematically. Individual ants are allowed to forage on a two-dimensional surface in the absence of any food sources. The position of the ant as a function of time is determined using a high-resolution digital camera. Analysis of the average square displacements of many ants suggests that the foraging strategy is a non-reversing random walk. Moreover, the ants do not retrace their steps to return home but instead continue the random walk until it brings them back near their starting point.

  14. Polyacrylamide hydrogels: an effective tool for delivering liquid baits to pest ants (Hymenoptera: Formicidae).

    PubMed

    Buczkowski, Grzegorz; Roper, Elray; Chin, Darren

    2014-04-01

    Ant management in urban and natural areas often relies on toxic baits. Liquid baits are highly attractive to pest ants because they mimic natural food sources such as honeydew and nectar, the principal dietary components of many ants. However, liquid bait use has been limited owing to the lack of bait dispensers that are effective, inexpensive, and easy to service. The current study evaluated the potential of water-storing crystals (polyacrylamide spheres) to effectively deliver liquid thiamethoxam baits to laboratory colonies of Argentine ants, Linepithema humile Mayr. Results of laboratory trials show that bait crystals saturated in 25% sucrose solution containing 0.007% thiamethoxam are highly attractive to Argentine ants and highly effective against all castes and life stages, including workers, queens, and brood. Fresh bait crystals were highly effective and required approximately 2 d to kill all workers and approximately 6 d to achieve complete mortality in queens and brood. Results of bait aging tests show that the crystals lose approximately 70% of moisture in 8 h and the duration of outdoor exposure has a significant effect on moisture loss and subsequently bait acceptance and bait efficacy. A gradual decrease in mortality was observed for all castes and life stages as bait age increased. In general, fresh baits and those aged for < 8 h retained their efficacy and caused substantial mortality. Baits aged longer than 8 h were substantially less attractive and less effective. Horizontal transfer tests examined the transfer of thiamethoxam from live treated donors to live untreated recipients. The results show that donor ants that obtain thiamethoxam by feeding on bait crystals effectively transfer it to untreated recipient ants. The level of secondary mortality depended on the donor:recipient ratio, with approximately 40% recipient worker mortality with the 1:5 ratio and 15% recipient worker mortality with 1:10 or 1:20 ratios. However, no queens died in any

  15. Wellbeing at work among kitchen workers during organic food conversion in Danish public kitchens: a longitudinal survey.

    PubMed

    Sørensen, Nina N; Løje, Hanne; Tetens, Inge; Wu, Jason H Y; Neal, Bruce; Lassen, Anne D

    2016-04-01

    In 2011, the Danish Ministry of Food, Agriculture and Fisheries launched the Danish Organic Action Plan 2020 intending to double the organic agricultural area in Denmark. This study aims to measure experienced physical and psychological wellbeing at work along with beliefs and attitudes among kitchen workers before and after participating in educational training programmes in organic food conversion. This longitudinal study applied an online self-administered questionnaire among kitchen workers before and after the implementation of an organic food conversion programme with 1-year follow-up. The study targeted all staff members in the participating public kitchens taking part in the organic food conversion process funded by the Danish Organic Action Plan 2020. Of the 448 eligible kitchen workers, 235 completed the questionnaire at baseline (52%) and 149 at follow-up (63% of those surveyed at baseline). No substantive differences between baseline and follow-up measurements of organic food conversion were detected on physical or psychological wellbeing at work. Kitchen workers reported a significant improvement in the perceived food quality, motivation to work and application of nutritional guidelines. Reported organic food percentages for the kitchens also increased significantly (P< 0.001) and a shift from using ready-made food products to producing more food from base was indicated. Within 1 year, a significant increase in motivation to work among kitchen staff was observed with no substantive changes in physical or psychological wellbeing at work identified. The results support the Danish Organic Action Plan 2020 and initiatives of similar kind. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  16. Food workers' perspectives on handwashing behaviors and barriers in the restaurant environment.

    PubMed

    Pragle, Aimee S; Harding, Anna K; Mack, James C

    2007-06-01

    Food handler focus groups in two Oregon counties discussed knowledge, practices, and barriers related to handwashing in the restaurant environment. Current knowledge-based handwashing training programs do not address the internal and external barriers that affect handwashing practice. According to the focus groups, important barriers were time pressure, inadequate facilities and supplies, lack of accountability, lack of involvement of managers and coworkers, and organizations that were not supportive of handwashing. Because barriers to handwashing are multi-dimensional in nature, the authors recommend that future educational and training programs include 1) a hands-on training program that orients new employees to correct handwashing practice and more advanced education about foodborne illness; 2) involvement of both managers and coworkers in the training; 3) easily accessible hand-washing facilities stocked with necessary supplies; 4) continued handwashing training and support involving the food service industry, managers, and coworkers; and 5) involvement of health departments and inspectors in providing managers and food workers with advice and consultation on improvement of handwashing practice.

  17. Exclusive rewards in mutualisms: ant proteases and plant protease inhibitors create a lock-key system to protect Acacia food bodies from exploitation.

    PubMed

    Orona-Tamayo, Domancar; Wielsch, Natalie; Blanco-Labra, Alejandro; Svatos, Ales; Farías-Rodríguez, Rodolfo; Heil, Martin

    2013-08-01

    Myrmecophytic Acacia species produce food bodies (FBs) to nourish ants of the Pseudomyrmex ferrugineus group, with which they live in an obligate mutualism. We investigated how the FBs are protected from exploiting nonmutualists. Two-dimensional gel electrophoresis of the FB proteomes and consecutive protein sequencing indicated the presence of several Kunitz-type protease inhibitors (PIs). PIs extracted from Acacia FBs were biologically active, as they effectively reduced the trypsin-like and elastase-like proteolytic activity in the guts of seed-feeding beetles (Prostephanus truncatus and Zabrotes subfasciatus), which were used as nonadapted herbivores representing potential exploiters. By contrast, the legitimate mutualistic consumers maintained high proteolytic activity dominated by chymotrypsin 1, which was insensitive to the FB PIs. Larvae of an exploiter ant (Pseudomyrmex gracilis) taken from Acacia hosts exhibited lower overall proteolytic activity than the mutualists. The proteases of this exploiter exhibited mainly elastase-like and to a lower degree chymotrypsin 1-like activity. We conclude that the mutualist ants possess specifically those proteases that are least sensitive to the PIs in their specific food source, whereas the congeneric exploiter ant appears partly, but not completely, adapted to consume Acacia FBs. By contrast, any consumption of the FBs by nonadapted exploiters would effectively inhibit their digestive capacities. We suggest that the term 'exclusive rewards' can be used to describe situations similar to the one that has evolved in myrmecophytic Acacia species, which reward mutualists with FBs but safeguard the reward from exploitation by generalists by making the FBs difficult for the nonadapted consumer to use.

  18. The adaptive significance of phasic colony cycles in army ants.

    PubMed

    Garnier, Simon; Kronauer, Daniel J C

    2017-09-07

    Army ants are top arthropod predators in tropical forests around the world. The colonies of many army ant species undergo stereotypical behavioral and reproductive cycles, alternating between brood care and reproductive phases. In the brood care phase, colonies contain a cohort of larvae that are synchronized in their development and have to be fed. In the reproductive phase larvae are absent and oviposition takes place. Despite these colony cycles being a striking feature of army ant biology, their adaptive significance is unclear. Here we use a modeling approach to show that cyclic reproduction is favored under conditions where per capita foraging costs decrease with the number of larvae in a colony ("High Cost of Entry" scenario), while continuous reproduction is favored under conditions where per capita foraging costs increase with the number of larvae ("Resource Exhaustion" scenario). We argue that the former scenario specifically applies to army ants, because large raiding parties are required to overpower prey colonies. However, once raiding is successful it provides abundant food for a large cohort of larvae. The latter scenario, on the other hand, will apply to non-army ants, because in those species local resource depletion will force workers to forage over larger distances to feed large larval cohorts. Our model provides a quantitative framework for understanding the adaptive value of phasic colony cycles in ants. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    PubMed

    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.

  20. 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

  1. Who needs 'lazy' workers? Inactive workers act as a 'reserve' labor force replacing active workers, but inactive workers are not replaced when they are removed.

    PubMed

    Charbonneau, Daniel; Sasaki, Takao; Dornhaus, Anna

    2017-01-01

    Social insect colonies are highly successful, self-organized complex systems. Surprisingly however, most social insect colonies contain large numbers of highly inactive workers. Although this may seem inefficient, it may be that inactive workers actually contribute to colony function. Indeed, the most commonly proposed explanation for inactive workers is that they form a 'reserve' labor force that becomes active when needed, thus helping mitigate the effects of colony workload fluctuations or worker loss. Thus, it may be that inactive workers facilitate colony flexibility and resilience. However, this idea has not been empirically confirmed. Here we test whether colonies of Temnothorax rugatulus ants replace highly active (spending large proportions of time on specific tasks) or highly inactive (spending large proportions of time completely immobile) workers when they are experimentally removed. We show that colonies maintained pre-removal activity levels even after active workers were removed, and that previously inactive workers became active subsequent to the removal of active workers. Conversely, when inactive workers were removed, inactivity levels decreased and remained lower post-removal. Thus, colonies seem to have mechanisms for maintaining a certain number of active workers, but not a set number of inactive workers. The rapid replacement (within 1 week) of active workers suggests that the tasks they perform, mainly foraging and brood care, are necessary for colony function on short timescales. Conversely, the lack of replacement of inactive workers even 2 weeks after their removal suggests that any potential functions they have, including being a 'reserve', are less important, or auxiliary, and do not need immediate recovery. Thus, inactive workers act as a reserve labor force and may still play a role as food stores for the colony, but a role in facilitating colony-wide communication is unlikely. Our results are consistent with the often cited, but never

  2. Steep Decline and Cessation in Seed Dispersal by Myrmica rubra Ants.

    PubMed

    Bologna, Audrey; Detrain, Claire

    2015-01-01

    Myrmecochorous diaspores bear a nutrient-rich appendage, the elaiosome, attractive to ant workers that retrieve them into the nest, detach the elaiosome and reject the seed intact. While this interaction is beneficial for the plant partner by ensuring its seed dispersal, elaiosome consumption has various effects -positive, negative or none - on ants' demography and survival, depending on both the ant/plant species involved. In this context, the contribution of ants to seed dispersal strongly varies according to the ant/plant pairs considered. In this paper, we investigate whether the dynamics of myrmecochory also vary on a temporal scale, for a given pair of partners: Myrmica rubra ants and Viola odorata seeds. During their first encounter with seeds, ants collect all the diaspores and eat the majority of elaiosomes. Both the harvesting effort and the elaiosome consumption decline when seeds are offered on the next week and completely cease for the following weeks. This is related to a decrease in the number of foragers reaching the food source, as well as to a reduced probability for an ant contacting a seed to retrieve it. Seed retrieval is not reactivated after seven weeks without any encounter with V. odorata seeds. By contrast, naive ant colonies only fed with fruit flies do not show a decline of prey harvesting of which the speed of retrieval even increases over the successive weeks. Myrmecochory may thus be labile at the scale of a fruiting season due to the ability of ants to steeply tune and cease for several months the harvesting of these seemingly poorly rewarding items and to maintain cessation of seed exploitation. The present study emphasizes the importance of a long-lasting follow up of the myrmecochory process, to assess the stability of this ant-plant partnership and to identify mechanisms of adaptive harvesting in ants.

  3. Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors

    PubMed Central

    Keller, Roberto A; Peeters, Christian; Beldade, Patrícia

    2014-01-01

    The concerted evolution of morphological and behavioral specializations has compelling examples in ant castes. Unique to ants is a marked divergence between winged queens and wingless workers, but morphological specializations for behaviors on the ground have been overlooked. We analyzed thorax morphology of queens and workers in species from 21 of the 25 ant subfamilies. We uncovered unique skeletomuscular modifications in workers that presumably increase power and flexibility of head–thorax articulation, emphasizing that workers are not simply wingless versions of queens. We also identified two distinct types of queens and showed repeated evolutionary associations with strategies of colony foundation. Solitary founding queens that hunt have a more worker-like thorax. Our results reveal that ants invest in the relative size of thorax segments according to their tasks. Versatility of head movements allows for better manipulation of food and objects, which arguably contributed to the ants’ ecological and evolutionary success. DOI: http://dx.doi.org/10.7554/eLife.01539.001 PMID:24399458

  4. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 4. Infective doses and pathogen carriage.

    PubMed

    Todd, Ewen C D; Greig, Judy D; Bartleson, Charles A; Michaels, Barry S

    2008-11-01

    In this article, the fourth in a series reviewing the role of food workers in foodborne outbreaks, background information on the presence of enteric pathogens in the community, the numbers of organisms required to initiate an infection, and the length of carriage are presented. Although workers have been implicated in outbreaks, they were not always aware of their infections, either because they were in the prodromic phase before symptoms began or because they were asymptomatic carriers. Pathogens of fecal, nose or throat, and skin origin are most likely to be transmitted by the hands, highlighting the need for effective hand hygiene and other barriers to pathogen contamination, such as no bare hand contact with ready-to-eat food. The pathogens most likely to be transmitted by food workers are norovirus, hepatitis A virus, Salmonella, Shigella, and Staphylococcus aureus. However, other pathogens have been implicated in worker-associated outbreaks or have the potential to be implicated. In this study, the likelihood of pathogen involvement in foodborne outbreaks where infected workers have been implicated was examined, based on infectious dose, carriage rate in the community, duration of illness, and length of pathogen excretion. Infectious dose estimates are based on volunteer studies (mostly early experiments) or data from outbreaks. Although there is considerable uncertainty associated with these data, some pathogens appear to be able to infect at doses as low as 1 to 100 units, including viruses, parasites, and some bacteria. Lengthy postsymptomatic shedding periods and excretion by asymptomatic individuals of many enteric pathogens is an important issue for the hygienic management of food workers.

  5. Does substrate coarseness matter for foraging ants? An experiment with Lasius niger (Hymenoptera; Formicidae).

    PubMed

    Bernadou, Abel; Fourcassié, Vincent

    2008-03-01

    We investigated whether workers of the ant species Lasius niger are able to sense and discriminate the coarseness of the substrate on which they walk. First, we studied the way in which substrate coarseness affects the ants' locomotory behaviour. Second, we investigated the spontaneous preference of ants for substrates of different coarseness. And third, we tested with a differential conditioning procedure the ants' capacity to learn to associate a given coarseness with a food reward. The locomotory behaviour of ants differed according to substrate coarseness: ants moved significantly faster and had more sinuous trajectories on a fine than on a coarse substrate. No spontaneous preference for a substrate of a given coarseness was observed and, even after 20 successive conditioning trials, there was little evidence of the effect of experience on substrate coarseness discrimination. Overall however, ants trained on fine sand made significantly more correct choice than those trained on coarse sand. We discuss these results and argue that in L. niger substrate coarseness may be more important at the collective level, by interacting with the chemical properties of the pheromone trail used in mass recruitment to food source, than at the individual level.

  6. Food safety knowledge, attitude, and practice toward compliance with abattoir laws among the abattoir workers in Malaysia.

    PubMed

    Abdullahi, Auwalu; Hassan, Azmi; Kadarman, Norizhar; Saleh, Ahmadu; Baraya, Yusha'u Shu'aibu; Lua, Pei Lin

    2016-01-01

    Foodborne diseases are common in the developing countries due to the predominant poor food handling and sanitation practices, particularly as a result of inadequate food safety laws, weak regulatory structures, and inadequate funding as well as a lack of appropriate education for food-handlers. The most frequently involved foods in disease outbreaks are of animal origin. However, in spite of the adequate legislation and laws governing the abattoir operation in Malaysia, compliance with food safety requirements during meat processing and waste disposal is inadequate. Therefore, the present study was designed to assess the food safety knowledge, attitude, and practice toward compliance with abattoir laws among the workers in Terengganu, Malaysia. A cross-sectional survey was conducted using simple random sampling technique in the six districts of Terengganu: two districts were used for the pilot study and the remaining four were used for the main study. One hundred sixty-five abattoir workers from the selected districts were interviewed using a structured questionnaire. The mean and standard deviation of knowledge, attitude, and practice scores of the workers were 6.02 and 1.954, 45.16 and 4.496, and 18.03 and 3.186, respectively. The majority of the workers (38.8%) had a low level of knowledge and 91.7% had a positive attitude, while 77.7% had a good practice of compliance. Sex had a significant association with the level of knowledge (P<0.001) and practice (P=0.044) among the workers. The females had a higher level of knowledge than the males, while the males had a better practice of compliance than females. Similarly, knowledge also had a significant (P=0.009) association with the level of practice toward compliance with abattoir laws among the workers. The abattoir workers had a positive attitude and good practice, but a low level of knowledge toward compliance with the abattoir laws. Therefore, public awareness, workshops, and seminars relevant to the abattoir

  7. Food safety knowledge, attitude, and practice toward compliance with abattoir laws among the abattoir workers in Malaysia

    PubMed Central

    Abdullahi, Auwalu; Hassan, Azmi; Kadarman, Norizhar; Saleh, Ahmadu; Baraya, Yusha’u Shu’aibu; Lua, Pei Lin

    2016-01-01

    Purpose Foodborne diseases are common in the developing countries due to the predominant poor food handling and sanitation practices, particularly as a result of inadequate food safety laws, weak regulatory structures, and inadequate funding as well as a lack of appropriate education for food-handlers. The most frequently involved foods in disease outbreaks are of animal origin. However, in spite of the adequate legislation and laws governing the abattoir operation in Malaysia, compliance with food safety requirements during meat processing and waste disposal is inadequate. Therefore, the present study was designed to assess the food safety knowledge, attitude, and practice toward compliance with abattoir laws among the workers in Terengganu, Malaysia. Materials and methods A cross-sectional survey was conducted using simple random sampling technique in the six districts of Terengganu: two districts were used for the pilot study and the remaining four were used for the main study. One hundred sixty-five abattoir workers from the selected districts were interviewed using a structured questionnaire. Results The mean and standard deviation of knowledge, attitude, and practice scores of the workers were 6.02 and 1.954, 45.16 and 4.496, and 18.03 and 3.186, respectively. The majority of the workers (38.8%) had a low level of knowledge and 91.7% had a positive attitude, while 77.7% had a good practice of compliance. Sex had a significant association with the level of knowledge (P<0.001) and practice (P=0.044) among the workers. The females had a higher level of knowledge than the males, while the males had a better practice of compliance than females. Similarly, knowledge also had a significant (P=0.009) association with the level of practice toward compliance with abattoir laws among the workers. Conclusion The abattoir workers had a positive attitude and good practice, but a low level of knowledge toward compliance with the abattoir laws. Therefore, public awareness

  8. Foraging behavior of the queenless ant Dinoponera quadriceps Santschi (Hymenoptera: Formicidae).

    PubMed

    Araújo, Arrilton; Rodrigues, Zenilde

    2006-01-01

    The search for and ingestion of food are essential to all animals, which spend most of their lives looking for nutritional sources, more than other activities such as mating, intra-specific disputes or escaping from predators. The present study aims to describe and quantify several aspects of foraging behavior, diet and food transport in the queenless ant Dinoponera quadriceps Santschi in a secondary Atlantic forest, Northeastern Brazil. Three colonies were randomly selected at a distance of at least 50 m from one another. On leaving the colony, worker ants were followed until their return, with no nutritional provision or interference with their activities. Activities were recorded using focal time sampling with instantaneous recording every minute for 10 consecutive minutes. Each colony was observed 1 day/week, for at least 6 h/day resulting in 53.8h of direct observation of the workers. Foraging activities, success in transporting food, type of food, cleaning and interaction among the workers were recorded. Foraging was always individual, with no occurrence of recruitment. Diet was composed mainly of arthropods, mostly insects. The collection of small fruits (Eugenia sp.) was also observed. Foraging time was greater when workers transported food to the colony, the return time being shorter than the foraging period, suggesting the use of chemical and visual cues for orientation during their foraging and food-collecting activities.

  9. Steep Decline and Cessation in Seed Dispersal by Myrmica rubra Ants

    PubMed Central

    2015-01-01

    Myrmecochorous diaspores bear a nutrient-rich appendage, the elaiosome, attractive to ant workers that retrieve them into the nest, detach the elaiosome and reject the seed intact. While this interaction is beneficial for the plant partner by ensuring its seed dispersal, elaiosome consumption has various effects −positive, negative or none − on ants’ demography and survival, depending on both the ant/plant species involved. In this context, the contribution of ants to seed dispersal strongly varies according to the ant/plant pairs considered. In this paper, we investigate whether the dynamics of myrmecochory also vary on a temporal scale, for a given pair of partners: Myrmica rubra ants and Viola odorata seeds. During their first encounter with seeds, ants collect all the diaspores and eat the majority of elaiosomes. Both the harvesting effort and the elaiosome consumption decline when seeds are offered on the next week and completely cease for the following weeks. This is related to a decrease in the number of foragers reaching the food source, as well as to a reduced probability for an ant contacting a seed to retrieve it. Seed retrieval is not reactivated after seven weeks without any encounter with V. odorata seeds. By contrast, naive ant colonies only fed with fruit flies do not show a decline of prey harvesting of which the speed of retrieval even increases over the successive weeks. Myrmecochory may thus be labile at the scale of a fruiting season due to the ability of ants to steeply tune and cease for several months the harvesting of these seemingly poorly rewarding items and to maintain cessation of seed exploitation. The present study emphasizes the importance of a long-lasting follow up of the myrmecochory process, to assess the stability of this ant-plant partnership and to identify mechanisms of adaptive harvesting in ants. PMID:26414161

  10. The effect of diet and opponent size on aggressive interactions involving caribbean crazy ants (Nylanderia fulva).

    PubMed

    Horn, Katherine C; Eubanks, Micky D; Siemann, Evan

    2013-01-01

    Biotic interactions are often important in the establishment and spread of invasive species. In particular, competition between introduced and native species can strongly influence the distribution and spread of exotic species and in some cases competition among introduced species can be important. The Caribbean crazy ant, Nylanderia fulva, was recently introduced to the Gulf Coast of Texas, and appears to be spreading inland. It has been hypothesized that competition with the red imported fire ant, Solenopsis invicta, may be an important factor in the spread of crazy ants. We investigated the potential of interspecific competition among these two introduced ants by measuring interspecific aggression between Caribbean crazy ant workers and workers of Solenopsis invicta. Specifically, we examined the effect of body size and diet on individual-level aggressive interactions among crazy ant workers and fire ants. We found that differences in diet did not alter interactions between crazy ant workers from different nests, but carbohydrate level did play an important role in antagonistic interactions with fire ants: crazy ants on low sugar diets were more aggressive and less likely to be killed in aggressive encounters with fire ants. We found that large fire ants engaged in fewer fights with crazy ants than small fire ants, but fire ant size affected neither fire ant nor crazy ant mortality. Overall, crazy ants experienced higher mortality than fire ants after aggressive encounters. Our findings suggest that fire ant workers might outcompete crazy ant workers on an individual level, providing some biotic resistance to crazy ant range expansion. However, this resistance may be overcome by crazy ants that have a restricted sugar intake, which may occur when crazy ants are excluded from resources by fire ants.

  11. The Effect of Diet and Opponent Size on Aggressive Interactions Involving Caribbean Crazy Ants (Nylanderia fulva)

    PubMed Central

    Horn, Katherine C.; Eubanks, Micky D.; Siemann, Evan

    2013-01-01

    Biotic interactions are often important in the establishment and spread of invasive species. In particular, competition between introduced and native species can strongly influence the distribution and spread of exotic species and in some cases competition among introduced species can be important. The Caribbean crazy ant, Nylanderia fulva, was recently introduced to the Gulf Coast of Texas, and appears to be spreading inland. It has been hypothesized that competition with the red imported fire ant, Solenopsis invicta, may be an important factor in the spread of crazy ants. We investigated the potential of interspecific competition among these two introduced ants by measuring interspecific aggression between Caribbean crazy ant workers and workers of Solenopsis invicta. Specifically, we examined the effect of body size and diet on individual-level aggressive interactions among crazy ant workers and fire ants. We found that differences in diet did not alter interactions between crazy ant workers from different nests, but carbohydrate level did play an important role in antagonistic interactions with fire ants: crazy ants on low sugar diets were more aggressive and less likely to be killed in aggressive encounters with fire ants. We found that large fire ants engaged in fewer fights with crazy ants than small fire ants, but fire ant size affected neither fire ant nor crazy ant mortality. Overall, crazy ants experienced higher mortality than fire ants after aggressive encounters. Our findings suggest that fire ant workers might outcompete crazy ant workers on an individual level, providing some biotic resistance to crazy ant range expansion. However, this resistance may be overcome by crazy ants that have a restricted sugar intake, which may occur when crazy ants are excluded from resources by fire ants. PMID:23776702

  12. Tournaments and slavery in a desert ant.

    PubMed

    Hölldobler, B

    1976-05-28

    Many species of ants engage in physical fighting when territorial borders are challenged. In contrast, colonies of the honeypot ant species Myrmecocystus mimicus conduct ritualized tournaments, in which hundreds of ants perform highly stereotyped display fights. Opposing colonies summon their worker forces to the tournament area by means of an alarm-recruitment system. When one colony is considerably stronger than the other, the tournament quickly ends, and the weaker colony is raided and its ants "enslaved." This is the first example of intraspecific slavery recorded in ants.

  13. Effects of Social Determinants on Chinese Immigrant Food Service Workers' Work Performance and Injuries: Mental Health as a Mediator.

    PubMed

    Tsai, Jenny Hsin-Chun; Thompson, Elaine Adams

    2015-07-01

    The effects of social discrimination, job concerns, and social support on worker mental health and the influence of mental health on occupational health outcomes have been documented intermittently. We propose an integrated, theory-driven model to distinguish the impact of social determinants on work performance and injuries and the mediating effects of mental health problems. The US Chinese immigrant food service workers (N = 194) completed a multimeasure interview; we tested the integrated model using structural equation modeling. Mental health problems, which were associated with decreased work performance and increased injuries, also mediated relationships between job/employment concerns and both work performance and injuries but did not mediate the influences of discrimination and social support. This research reveals mechanisms by which social determinants influence immigrant worker health, pointing to complementary strategies for reducing occupational health disparities.

  14. Association between the use of biomass fuels on respiratory health of workers in food catering enterprises in Nairobi Kenya

    PubMed Central

    Keraka, Margaret; Ochieng, Carolyne; Engelbrecht, Jacobus; Hongoro, Charles

    2013-01-01

    Introduction Indoor air pollution from biomass fuel use has been found to be responsible for more than 1.6 million annual deaths and 2.7% of the global burden of disease. This makes it the second biggest environmental contributor to ill health, behind unsafe water and sanitation. Methods The main objective of this study was to investigate if there was any association between use of bio-fuels in food catering enterprises and respiratory health of the workers. A cross-sectional design was employed, and data collected using Qualitative and quantitative techniques. Results The study found significantly higher prevalence of respiratory health outcomes among respondents in enterprises using biomass fuels compared to those using processed fuels. Biomass fuels are thus a major public health threat to workers in this sub-sector, and urgent intervention is required. Conclusion The study recommends a switch from biomass fuels to processed fuels to protect the health of the workers. PMID:23898361

  15. Association between the use of biomass fuels on respiratory health of workers in food catering enterprises in Nairobi Kenya.

    PubMed

    Keraka, Margaret; Ochieng, Carolyne; Engelbrecht, Jacobus; Hongoro, Charles

    2013-01-01

    Indoor air pollution from biomass fuel use has been found to be responsible for more than 1.6 million annual deaths and 2.7% of the global burden of disease. This makes it the second biggest environmental contributor to ill health, behind unsafe water and sanitation. The main objective of this study was to investigate if there was any association between use of bio-fuels in food catering enterprises and respiratory health of the workers. A cross-sectional design was employed, and data collected using Qualitative and quantitative techniques. The study found significantly higher prevalence of respiratory health outcomes among respondents in enterprises using biomass fuels compared to those using processed fuels. Biomass fuels are thus a major public health threat to workers in this sub-sector, and urgent intervention is required. The study recommends a switch from biomass fuels to processed fuels to protect the health of the workers.

  16. 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.

  17. No sex in fungus-farming ants or their crops

    PubMed Central

    Himler, Anna G.; Caldera, Eric J.; Baer, Boris C.; Fernández-Marín, Hermógenes; Mueller, Ulrich G.

    2009-01-01

    Asexual reproduction imposes evolutionary handicaps on asexual species, rendering them prone to extinction, because asexual reproduction generates novel genotypes and purges deleterious mutations at lower rates than sexual reproduction. Here, we report the first case of complete asexuality in ants, the fungus-growing ant Mycocepurus smithii, where queens reproduce asexually but workers are sterile, which is doubly enigmatic because the clonal colonies of M. smithii also depend on clonal fungi for food. Degenerate female mating anatomy, extensive field and laboratory surveys, and DNA fingerprinting implicate complete asexuality in this widespread ant species. Maternally inherited bacteria (e.g. Wolbachia, Cardinium) and the fungal cultivars can be ruled out as agents inducing asexuality. M. smithii societies of clonal females provide a unique system to test theories of parent–offspring conflict and reproductive policing in social insects. Asexuality of both ant farmer and fungal crop challenges traditional views proposing that sexual farmer ants outpace coevolving sexual crop pathogens, and thus compensate for vulnerabilities of their asexual crops. Either the double asexuality of both farmer and crop may permit the host to fully exploit advantages of asexuality for unknown reasons or frequent switching between crops (symbiont reassociation) generates novel ant–fungus combinations, which may compensate for any evolutionary handicaps of asexuality in M. smithii. PMID:19369264

  18. Ant-like task allocation and recruitment in cooperative robots.

    PubMed

    Krieger, M J; Billeter, J B; Keller, L

    2000-08-31

    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.

  19. Ant Tower

    NASA Astrophysics Data System (ADS)

    Mlot, Nathan; Shinotsuka, Sho; Hu, David

    2010-11-01

    Ants walk via adhesive drops of fluid extruded by their feet. They also use these drops as mortar to build structures such as rafts, bridges and towers, each composed of thousands of ants linked together. We investigate experimentally the construction of triangular ant towers braced by hydrophobic walls. Particular attention is paid to the relationship between tower height and contact angle hysteresis of the wall. We rationalize tower height according to ant adhesion, and tower shape according to the constraints on a column of constant strength.

  20. A temporary social parasite of tropical plant-ants improves the fitness of a myrmecophyte

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Leroy, Céline; Corbara, Bruno; Céréghino, Régis; Roux, Olivier; Hérault, Bruno; Rossi, Vivien; Guerrero, Roberto J.; Delabie, Jacques H. C.; Orivel, Jérôme; Boulay, Raphaël

    2010-10-01

    Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant-plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant-myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia ( Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca- Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees’ fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non- Cecropia tree.

  1. Evaluation of the nutritional status of workers of transformation industries adherent to the Brazilian Workers’ Food Program. A comparative study

    PubMed Central

    Oliveira, António Gouveia; Sampaio, Luciano M. B.

    2017-01-01

    The objective of this study was to assess whether the Brazilian Workers’ Food Program (WFP) is associated with changes in the nutritional status of workers in the transformation industry. We conducted a cross-sectional, observational, comparative study, based on prospectively collected data from a combined stratified and two-stage probability sample of workers from 26 small and medium size companies, 13 adherent and 13 non-adherent to the WFP, in the food, mining and textile sectors. Study variables were body mass index (BMI), waist circumference (WC), and dietary intake at lunch obtained by 24-hour dietary recall. Data were analyzed with nested mixed effects linear regression with adjustment by subject variables. Sampling weights were applied in computing population parameters. The final sample consisted of 1069 workers, 541 from WFP-adherent and 528 from WFP non-adherent companies. The groups were different only in education level, income and in-house training. Workers in WFP-adherent companies have greater BMI (27.0 kg/m2 vs. 26.0 kg/m2, p = 0.002) and WC (87.9 cm vs. 86.5, p = 0.04), higher prevalence of excessive weight (62.6% vs. 55.5%, p<0.001) and of increased WC (49.1% vs. 39.9%). Workers of WFP companies have lower intake of saturated fat (–1.34 g, p<0.01) and sodium (–0.3 g, p<0.01) at lunch. In conclusion, this study showed that workers of companies adherent to the Brazilian WFP have greater rates of excessive weight and increased cardiovascular risk—a negative finding—as well as lower intake of sodium and saturated fat—a positive finding. Therefore, the WFP needs to be revisited and its aims redefined according to the current epidemiological status of the target population of the program. PMID:28182763

  2. [Evaluation of Brazilian public policies to promote food security and fight hunger, 1995-2002. 2 - the Workers' Nutrition Program].

    PubMed

    Pacheco Santos, Leonor Maria; Nazaré Araújo, Maria da Purificação; Martins, Maísa Cruz; Veloso, Iracema Santos; Assunção, Marilena Pacheco; Chaves dos Santos, Sandra Maria

    2007-08-01

    This study evaluated the Workers' Nutrition Program in Brazil from 1995 to 2002, from a structure-process-results perspective. The methodology involved documental research and a case study in 45 municipalities in the State of Bahia, resulting in 2,389 household interviews. In relation to structure, we analyzed the program's normative evolution until 2002. As for nutritional recommendations, the program shifted from insufficient calorie supply in the 1980s to a positive association between overweight and employment in companies adopting the Workers' Nutrition Program. In Bahia, overall program coverage was insufficient among the 5,120 adults 20 years or older who were interviewed. A significant difference was observed in access to food benefits among workers in the interior of the State (6.1%) as compared to the State capital, Salvador (26.1%). However, targeting was adequate: all workers benefiting from the program in the interior and 92.4% of those in Salvador earned less than five times the minimum wage (approximately US dollars 950/month). It is necessary to improve the program's coverage in the target population in order to raise workers' awareness about their rights and the actions developed by the program.

  3. Polydomy enhances foraging performance in ant colonies.

    PubMed

    Stroeymeyt, N; Joye, P; Keller, L

    2017-04-26

    Collective foraging confers benefits in terms of reduced predation risk and access to social information, but it heightens local competition when resources are limited. In social insects, resource limitation has been suggested as a possible cause for the typical decrease in per capita productivity observed with increasing colony size, a phenomenon known as Michener's paradox. Polydomy (distribution of a colony's brood and workers across multiple nests) is believed to help circumvent this paradox through its positive effect on foraging efficiency, but there is still little supporting evidence for this hypothesis. Here, we show experimentally that polydomy enhances the foraging performance of food-deprived Temnothorax nylanderi ant colonies via several mechanisms. First, polydomy influences task allocation within colonies, resulting in faster retrieval of protein resources. Second, communication between sister nests reduces search times for far away resources. Third, colonies move queens, brood and workers across available nest sites in response to spatial heterogeneities in protein and carbohydrate resources. This suggests that polydomy represents a flexible mechanism for space occupancy, helping ant colonies adjust to the environment. © 2017 The Author(s).

  4. Antagonistic Interactions between the African Weaver Ant Oecophylla longinoda and the Parasitoid Anagyrus pseudococci Potentially Limits Suppression of the Invasive Mealybug Rastrococcus iceryoides.

    PubMed

    Tanga, Chrysantus M; Ekesi, Sunday; Govender, Prem; Nderitu, Peterson W; Mohamed, Samira A

    2015-12-23

    The ant Oecophylla longinoda Latreille forms a trophobiotic relationship with the invasive mealybug Rastrococus iceryoides Green and promotes the latter's infestations to unacceptable levels in the presence of their natural enemies. In this regard, the antagonistic interactions between the ant and the parasitoid Anagyrus pseudococci Girault were assessed under laboratory conditions. The percentage of parasitism of R. iceryoides by A. pseudococci was significantly higher on "ant-excluded" treatments (86.6% ± 1.27%) compared to "ant-tended" treatments (51.4% ± 4.13%). The low female-biased sex-ratio observed in the "ant-tended" treatment can be attributed to ants' interference during the oviposition phase, which disrupted parasitoids' ability to fertilize eggs. The mean foraging time, host handling time and number of successful oviposition in "ant-excluded" treatment were significantly higher compared to "ant-tended" treatments. When ant workers were allowed access to sterilized sand grains, mummified and unmummified R. iceryoides, they selectively removed the mummified mealybugs, indicating that they recognized the mummies as potential foods (1.2 ± 0.46 to 7.8 ± 1.17 mummies at 10 min intervals for 2 h). Percentage emergence from mummified R. iceryoides removed by the ants was significantly lower compared to emergence from mummies not exposed to ants. Although, host seeking parasitoids frequently evaded attacks, some were killed by the foraging ant workers (2.0 ± 0.38 to 6.0 ± 0.88 at 10 min intervals for 2 h). These results suggest for the first time that the presence of O. longinoda has a detrimental effect on the abundance, reproductive success and possibly oviposition strategy of female parasitoids, which might be a delimiting factor in field conditions if both natural enemies are to be recommended for use within the same agro-ecosystem.

  5. How plants shape the ant community in the Amazonian rainforest canopy: the key role of extrafloral nectaries and homopteran honeydew.

    PubMed

    Blüthgen, N; Verhaagh, M; Goitía, W; Jaffé, K; Morawetz, W; Barthlott, W

    2000-10-01

    Ant-plant interactions in the canopy of a lowland Amazonian rainforest of the upper Orinoco, Venezuela, were studied using a modified commercial crane on rails (Surumoni project). Our observations show a strong correlation between plant sap exudates and both abundance of ants and co-occurrence of ant species in tree canopies. Two types of plant sap sources were compared: extrafloral nectaries (EFNs) and honeydew secretions by homopterans. EFNs were a frequent food source for ants on epiphytes (Philodendron spp., Araceae) and lianas (Dioclea, Fabaceae), but rare on canopy trees in the study area, whereas the majority of trees were host to aggregations of homopterans tended by honeydew-seeking ants (on 62% of the trees examined). These aggregations rarely occurred on epiphytes. Baited ant traps were installed on plants with EFNs and in the crowns of trees from three common genera, including trees with and without ant-tended homopterans: Goupia glabra (Celastraceae), Vochysia spp. (Vochysiaceae), and Xylopia spp. (Annonaceae). The number of ant workers per trap was significantly higher on plants offering one of the two plant sap sources than on trees without such resources. Extrafloral nectaries were used by a much broader spectrum of ant species and genera than honeydew, and co-occurrence of ant species (in traps) was significantly higher on plants bearing EFNs than on trees. Homopteran honeydew (Coccidae and Membracidae), on the other hand, was mostly monopolised by a single ant colony per tree. Homopteran-tending ants were generally among the most dominant ants in the canopy. The most prominent genera were Azteca, Dolichoderus (both Dolichoderinae), Cephalotes, Pheidole, Crematogaster (all Myrmicinae), and Ectatomma (Ponerinae). Potential preferences were recorded between ant and homopteran species, and also between ant-homopteran associations and tree genera. We hypothesize that the high availability of homopteran honeydew provides a key resource for ant mosaics

  6. Routing Vehicles with Ants

    NASA Astrophysics Data System (ADS)

    Tan, Wen Fang; Lee, Lai Soon; Majid, Zanariah Abdul; Seow, Hsin Vonn

    Routing vehicles involve the design of an optimal set of routes for a fleet of vehicles to serve a number of customers with known demands. This research develops an Ant Colony Optimization for the vehicle routing with one central depot and identical vehicles. The procedure simulates the behavior of real ants that always find the shortest path between their nest and a food source through a form of communication, pheromone trail. Finally, preliminary results on the learning of the algorithm testing on benchmark data set will be presented in this paper.

  7. Food Production, Management, and Services Programs. Food Service Worker. Performance Objectives and Criterion-Referenced Test Items.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    To assist instructors in implementing Missouri's Vocational Instructional Management System into the Food Production, Management, and Services Programs, this guide sets forth the competencies identified and validated by occupational food service instructors and personnel from the food service industry. A minimum of two performance objectives per…

  8. Nesting habits shape feeding preferences and predatory behavior in an ant genus.

    PubMed

    Dejean, Alain; Labrière, Nicolas; Touchard, Axel; Petitclerc, Frédéric; Roux, Olivier

    2014-04-01

    We tested if nesting habits influence ant feeding preferences and predatory behavior in the monophyletic genus Pseudomyrmex (Pseudomyrmecinae) which comprises terrestrial and arboreal species, and, among the latter, plant-ants which are obligate inhabitants of myrmecophytes (i.e., plants sheltering so-called plant-ants in hollow structures). A cafeteria experiment revealed that the diet of ground-nesting Pseudomyrmex consists mostly of prey and that of arboreal species consists mostly of sugary substances, whereas the plant-ants discarded all the food we provided. Workers forage solitarily, detecting prey from a distance thanks to their hypertrophied eyes. Approach is followed by antennal contact, seizure, and the manipulation of the prey to sting it under its thorax (next to the ventral nerve cord). Arboreal species were not more efficient at capturing prey than were ground-nesting species. A large worker size favors prey capture. Workers from ground- and arboreal-nesting species show several uncommon behavioral traits, each known in different ant genera from different subfamilies: leaping abilities, the use of surface tension strengths to transport liquids, short-range recruitment followed by conflicts between nestmates, the consumption of the prey's hemolymph, and the retrieval of entire prey or pieces of prey after having cut it up. Yet, we never noted group ambushing. We also confirmed that Pseudomyrmex plant-ants live in a kind of food autarky as they feed only on rewards produced by their host myrmecophyte, or on honeydew produced by the hemipterans they attend and possibly on the fungi they cultivate.

  9. Nesting habits shape feeding preferences and predatory behavior in an ant genus

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Labrière, Nicolas; Touchard, Axel; Petitclerc, Frédéric; Roux, Olivier

    2014-04-01

    We tested if nesting habits influence ant feeding preferences and predatory behavior in the monophyletic genus Pseudomyrmex (Pseudomyrmecinae) which comprises terrestrial and arboreal species, and, among the latter, plant-ants which are obligate inhabitants of myrmecophytes (i.e., plants sheltering so-called plant-ants in hollow structures). A cafeteria experiment revealed that the diet of ground-nesting Pseudomyrmex consists mostly of prey and that of arboreal species consists mostly of sugary substances, whereas the plant-ants discarded all the food we provided. Workers forage solitarily, detecting prey from a distance thanks to their hypertrophied eyes. Approach is followed by antennal contact, seizure, and the manipulation of the prey to sting it under its thorax (next to the ventral nerve cord). Arboreal species were not more efficient at capturing prey than were ground-nesting species. A large worker size favors prey capture. Workers from ground- and arboreal-nesting species show several uncommon behavioral traits, each known in different ant genera from different subfamilies: leaping abilities, the use of surface tension strengths to transport liquids, short-range recruitment followed by conflicts between nestmates, the consumption of the prey's hemolymph, and the retrieval of entire prey or pieces of prey after having cut it up. Yet, we never noted group ambushing. We also confirmed that Pseudomyrmex plant-ants live in a kind of food autarky as they feed only on rewards produced by their host myrmecophyte, or on honeydew produced by the hemipterans they attend and possibly on the fungi they cultivate.

  10. Arboreal Ants Use the “Velcro® Principle” to Capture Very Large Prey

    PubMed Central

    Dejean, Alain; Leroy, Céline; Corbara, Bruno; Roux, Olivier; Céréghino, Régis; Orivel, Jérôme; Boulay, Raphaël

    2010-01-01

    Plant-ants live in a mutualistic association with host plants known as “myrmecophytes” that provide them with a nesting place and sometimes with extra-floral nectar (EFN) and/or food bodies (FBs); the ants can also attend sap-sucking Hemiptera for their honeydew. In return, plant-ants, like most other arboreal ants, protect their host plants from defoliators. To satisfy their nitrogen requirements, however, some have optimized their ability to capture prey in the restricted environment represented by the crowns of trees by using elaborate hunting techniques. In this study, we investigated the predatory behavior of the ant Azteca andreae which is associated with the myrmecophyte Cecropia obtusa. We noted that up to 8350 ant workers per tree hide side-by-side beneath the leaf margins of their host plant with their mandibles open, waiting for insects to alight. The latter are immediately seized by their extremities, and then spread-eagled; nestmates are recruited to help stretch, carve up and transport prey. This group ambush hunting technique is particularly effective when the underside of the leaves is downy, as is the case for C. obtusa. In this case, the hook-shaped claws of the A. andreae workers and the velvet-like structure of the underside of the leaves combine to act like natural Velcro® that is reinforced by the group ambush strategy of the workers, allowing them to capture prey of up to 13,350 times the mean weight of a single worker. PMID:20593032

  11. Evolution of gene expression in fire ants: the effects of developmental stage, caste, and species.

    PubMed

    Ometto, Lino; Shoemaker, DeWayne; Ross, Kenneth G; Keller, Laurent

    2011-04-01

    Ants provide remarkable examples of equivalent genotypes developing into divergent and discrete phenotypes. Diploid eggs can develop either into queens, which specialize in reproduction, or workers, which participate in cooperative tasks such as building the nest, collecting food, and rearing the young. In contrast, the differentiation between males and females generally depends upon whether eggs are fertilized, with fertilized (diploid) eggs giving rise to females and unfertilized (haploid) eggs giving rise to males. To obtain a comprehensive picture of the relative contributions of gender (sex), caste, developmental stage, and species divergence to gene expression evolution, we investigated gene expression patterns in pupal and adult queens, workers, and males of two species of fire ants, Solenopsis invicta and S. richteri. Microarray hybridizations revealed that variation in gene expression profiles is influenced more by developmental stage than by caste membership, sex, or species identity. The second major contributor to variation in gene expression was the combination of sex and caste. Although workers and queens share equivalent diploid nuclear genomes, they have highly distinctive patterns of gene expression in both the pupal and the adult stages, as might be expected given their extraordinary level of phenotypic differentiation. Overall, the difference in the proportion of differentially expressed genes was greater between workers and males than between workers and queens or queens and males, consistent with the fact that workers and males share neither gender nor reproductive capability. Moreover, between-species comparisons revealed that the greatest difference in gene expression patterns occurred in adult workers, a finding consistent with the fact that adult workers most directly experience the distinct external environments characterizing the different habitats occupied by the two species. Thus, much of the evolution of gene expression in ants may

  12. [The role of motivation in the performance of a conditioned switching-over of the maze habit in ants Myrmica rubra after a change in the quality of the food reinforcement].

    PubMed

    Udalova, G P; Karas', A Ia

    2005-01-01

    Active foragers Myrmica rubra were trained in a maze under conditions of different levels of colony need in food with carbohydrate (sugar syrup) or protein (ants Lasius niger pupae) reinforcement. Acquisition of the maze habit was better under conditions of reinforcement with pupae, especially by its time indices. Ants were able to modify the acquired habit when the reinforcement quality was changed. It was shown that learning was possible only when the colony and after a change pupae for the syrup was "hungry". Under these conditions, after a change of the syrup for pupae or visa versa the previously acquired optimum habit was transferred. Several hours later, with satiation of the colony, food reactions learned with protein reinforcement switched-over to "stochastic" non-optimized behavior with the dominance of exploratory reactions. Thus, it was shown that higher social insects ants were capable for conditioned switching-over. Different forms of this phenomenon depended on the level of the colony need in food and, consequently, on the level of the social food motivation of foragers ants.

  13. Introduced fire ants can exclude native ants from critical mutualist-provided resources.

    PubMed

    Wilder, Shawn M; Barnum, Thomas R; Holway, David A; Suarez, Andrew V; Eubanks, Micky D

    2013-05-01

    Animals frequently experience resource imbalances in nature. For ants, one resource that may be particularly valuable for both introduced and native species is high-carbohydrate honeydew from hemipteran mutualists. We conducted field and laboratory experiments: (1) to test if red imported fire ants (Solenopsis invicta) competed with native ants for access to mutualisms with aphids, and (2) to quantify the effects of aphid honeydew presence or absence on colony growth of native ants. We focused on native dolichoderine ants (Formicidae, Dolichoderinae) because they are abundant ants that have omnivorous diets that frequently include mutualist-provided carbohydrates. At two sites in the southeastern US, native dolichoderine ants were far less frequent, and fire ants more frequent, at carbohydrate baits than would be expected based on their frequency in pitfall traps. A field experiment confirmed that a native ant species, Dorymyrmex bureni, was only found tending aphids when populations of S. invicta were suppressed. In the laboratory, colonies of native dolichoderine ants with access to both honeydew and insect prey had twice as many workers and over twice as much brood compared to colonies fed only ad libitum insect prey. Our results provide the first experimental evidence that introduced ants compete for access to mutualist-provided carbohydrates with native ants and that these carbohydrates represent critical resources for both introduced and native ants. These results challenge traditional paradigms of arthropod and ant nutrition and contribute to growing evidence of the importance of nutrition in mediating ecological interactions.

  14. Food insecurity, HIV/AIDS pandemic and sexual behaviour of female commercial sex workers in Lagos metropolis, Nigeria.

    PubMed

    Oyefara, J L

    2007-08-01

    This study examined the role of hunger and food insecurity in the sexual behaviour of female commercial sex workers in Lagos metropolis, Nigeria within the context of HIV/AIDS. In addition, the study investigated the prevalence of sexually transmitted infections (STIs) and induced abortion among the respondents. Cross-sectional survey and in-depth interview research methods were adopted to generate both quantitative and qualitative data from the respondents. Findings of the study showed that 35.0% of the respondents joined the sex industry because of poverty and lack of other means of getting daily food. While all the respondents had knowledge about the existence of HIV/AIDS, 82.0% of them identified sexual intercourse as a major route of HIV transmission. There was a significant relationship between poverty, food insecurity and consistent use of condoms by female sex workers at P<0.01. Specifically, only 24.7% of the respondents used condoms regularly in every sexual act. Consequently, 51.6% had previous cases of STIs. The most prevalent STI among the respondents was gonorrhea, with 76.4% prevalence among ever infected female sex workers. This was followed by syphilis with a prevalence of 21.1%. In addition, 59.1% of the sample had become pregnant while on the job and 93.1% of these pregnancies were aborted through induced abortion. In conclusion, hunger and malnutrition were the factors that pushed young women into prostitution in Nigeria and these same factors hindered them from practicing safe sex within the sex industry. Thus, it is recommended that the Nigerian government should develop programmes that will reduce hunger and food insecurity, in order to reduce rapid transmission of HIV infection in the country.

  15. Diacetyl and 2,3-pentanedione exposures associated with cigarette smoking: implications for risk assessment of food and flavoring workers.

    PubMed

    Pierce, Jennifer S; Abelmann, Anders; Spicer, Lauren J; Adams, Rebecca E; Finley, Brent L

    2014-05-01

    Diacetyl and 2,3-pentanedione inhalation have been suggested as causes of severe respiratory disease, including bronchiolitis obliterans, in food/flavoring manufacturing workers. Both compounds are present in many food items, tobacco, and other consumer products, but estimates of exposures associated with the use of these goods are scant. A study was conducted to characterize exposures to diacetyl and 2,3-pentanedione associated with cigarette smoking. The yields (μg/cigarette) of diacetyl and 2,3-pentanedione in mainstream (MS) cigarette smoke were evaluated for six tobacco products under three smoking regimens (ISO, Massachusetts Department of Public Health, and Health Canada Intense) using a standard smoking machine. Mean diacetyl concentrations in MS smoke ranged from 250 to 361 ppm for all tobacco products and smoking regimens, and mean cumulative exposures associated with 1 pack-year ranged from 1.1 to 1.9 ppm-years. Mean 2,3-pentanedione concentrations in MS smoke ranged from 32.2 to 50.1 ppm, and mean cumulative exposures associated with 1 pack-year ranged from 0.14 to 0.26 ppm-years. We found that diacetyl and 2,3-pentanedione exposures from cigarette smoking far exceed occupational exposures for most food/flavoring workers who smoke. This suggests that previous claims of a significant exposure-response relationship between diacetyl inhalation and respiratory disease in food/flavoring workers were confounded, because none of the investigations considered or quantified the non-occupational diacetyl exposure from cigarette smoke, yet all of the cohorts evaluated had considerable smoking histories. Further, because smoking has not been shown to be a risk factor for bronchiolitis obliterans, our findings are inconsistent with claims that diacetyl and/or 2,3-pentanedione exposure are risk factors for this disease.

  16. Host Plant Use by Competing Acacia-Ants: Mutualists Monopolize While Parasites Share Hosts

    PubMed Central

    Kautz, Stefanie; Ballhorn, Daniel J.; Kroiss, Johannes; Pauls, Steffen U.; Moreau, Corrie S.; Eilmus, Sascha; Strohm, Erhard; Heil, Martin

    2012-01-01

    Protective ant-plant mutualisms that are exploited by non-defending parasitic ants represent prominent model systems for ecology and evolutionary biology. The mutualist Pseudomyrmex ferrugineus is an obligate plant-ant and fully depends on acacias for nesting space and food. The parasite Pseudomyrmex gracilis facultatively nests on acacias and uses host-derived food rewards but also external food sources. Integrative analyses of genetic microsatellite data, cuticular hydrocarbons and behavioral assays showed that an individual acacia might be inhabited by the workers of several P. gracilis queens, whereas one P. ferrugineus colony monopolizes one or more host trees. Despite these differences in social organization, neither of the species exhibited aggressive behavior among conspecific workers sharing a tree regardless of their relatedness. This lack of aggression corresponds to the high similarity of cuticular hydrocarbon profiles among ants living on the same tree. Host sharing by unrelated colonies, or the presence of several queens in a single colony are discussed as strategies by which parasite colonies could achieve the observed social organization. We argue that in ecological terms, the non-aggressive behavior of non-sibling P. gracilis workers — regardless of the route to achieve this social structure — enables this species to efficiently occupy and exploit a host plant. By contrast, single large and long-lived colonies of the mutualist P. ferrugineus monopolize individual host plants and defend them aggressively against invaders from other trees. Our findings highlight the necessity for using several methods in combination to fully understand how differing life history strategies affect social organization in ants. PMID:22662191

  17. Host plant use by competing acacia-ants: mutualists monopolize while parasites share hosts.

    PubMed

    Kautz, Stefanie; Ballhorn, Daniel J; Kroiss, Johannes; Pauls, Steffen U; Moreau, Corrie S; Eilmus, Sascha; Strohm, Erhard; Heil, Martin

    2012-01-01

    Protective ant-plant mutualisms that are exploited by non-defending parasitic ants represent prominent model systems for ecology and evolutionary biology. The mutualist Pseudomyrmex ferrugineus is an obligate plant-ant and fully depends on acacias for nesting space and food. The parasite Pseudomyrmex gracilis facultatively nests on acacias and uses host-derived food rewards but also external food sources. Integrative analyses of genetic microsatellite data, cuticular hydrocarbons and behavioral assays showed that an individual acacia might be inhabited by the workers of several P. gracilis queens, whereas one P. ferrugineus colony monopolizes one or more host trees. Despite these differences in social organization, neither of the species exhibited aggressive behavior among conspecific workers sharing a tree regardless of their relatedness. This lack of aggression corresponds to the high similarity of cuticular hydrocarbon profiles among ants living on the same tree. Host sharing by unrelated colonies, or the presence of several queens in a single colony are discussed as strategies by which parasite colonies could achieve the observed social organization. We argue that in ecological terms, the non-aggressive behavior of non-sibling P. gracilis workers--regardless of the route to achieve this social structure--enables this species to efficiently occupy and exploit a host plant. By contrast, single large and long-lived colonies of the mutualist P. ferrugineus monopolize individual host plants and defend them aggressively against invaders from other trees. Our findings highlight the necessity for using several methods in combination to fully understand how differing life history strategies affect social organization in ants.

  18. Stinging ants.

    PubMed

    Rhoades, R

    2001-08-01

    Ants belong to the order Hymenoptera, along with bees, wasps, yellow jackets, etc., they are the most successful animal genera in this world. It is their selfless social structure which accounts for their huge impact. Their effect on man ranges from the parasol ant, which makes plant cultivation untenable in certain parts of South America, to Solenopsis Invicta in the southeastern United States of America, which kill ground dwelling birds and small animals, harass livestock, and renders farmland unusable. With the exception of the Bulldog Ant of Australia (which is the size of a medium cockroach) direct toxic effects are not a lethal threat to man. Human fatalities and morbidity are related to secondary infections of excoriated stings or allergic anaphylaxis. This article reviews history and recent developments regarding stinging ants around the world.

  19. Ants, Wasps, and Bees (Hymenoptera)

    USDA-ARS?s Scientific Manuscript database

    Stinging wasps, bees, and ants are a problem for farm workers, particularly at harvest when these insects are attracted to ripe fruits. Researchers at the USDA-ARS Yakima Agricultural Research Laboratory, Wapato, WA, together with personnel at Oral Roberts University compiled available information o...

  20. Food Service Worker. Instructional Modules for Food Management, Production and Services. Modules 1-17. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Tennessee Univ., Knoxville. Dept. of Vocational-Technical Education.

    These 17 teacher modules are part of a curriculum dealing with food management, production, and services that was developed for use in secondary and postsecondary vocational programs in Tennessee. Covered in the individual modules are food service careers, math skills, reading and converting recipes, work simplification, self-development,…

  1. Antagonistic Interactions between the African Weaver Ant Oecophylla longinoda and the Parasitoid Anagyrus pseudococci Potentially Limits Suppression of the Invasive Mealybug Rastrococcus iceryoides

    PubMed Central

    Tanga, Chrysantus M.; Ekesi, Sunday; Govender, Prem; Nderitu, Peterson W.; Mohamed, Samira A.

    2015-01-01

    The ant Oecophylla longinoda Latreille forms a trophobiotic relationship with the invasive mealybug Rastrococus iceryoides Green and promotes the latter’s infestations to unacceptable levels in the presence of their natural enemies. In this regard, the antagonistic interactions between the ant and the parasitoid Anagyrus pseudococci Girault were assessed under laboratory conditions. The percentage of parasitism of R. iceryoides by A. pseudococci was significantly higher on “ant-excluded” treatments (86.6% ± 1.27%) compared to “ant-tended” treatments (51.4% ± 4.13%). The low female-biased sex-ratio observed in the “ant-tended” treatment can be attributed to ants’ interference during the oviposition phase, which disrupted parasitoids’ ability to fertilize eggs. The mean foraging time, host handling time and number of successful oviposition in “ant-excluded” treatment were significantly higher compared to “ant-tended” treatments. When ant workers were allowed access to sterilized sand grains, mummified and unmummified R. iceryoides, they selectively removed the mummified mealybugs, indicating that they recognized the mummies as potential foods (1.2 ± 0.46 to 7.8 ± 1.17 mummies at 10 min intervals for 2 h). Percentage emergence from mummified R. iceryoides removed by the ants was significantly lower compared to emergence from mummies not exposed to ants. Although, host seeking parasitoids frequently evaded attacks, some were killed by the foraging ant workers (2.0 ± 0.38 to 6.0 ± 0.88 at 10 min intervals for 2 h). These results suggest for the first time that the presence of O. longinoda has a detrimental effect on the abundance, reproductive success and possibly oviposition strategy of female parasitoids, which might be a delimiting factor in field conditions if both natural enemies are to be recommended for use within the same agro-ecosystem. PMID:26703741

  2. The Effects of industrial workers' food choice attribute on sugar intake pattern and job satisfaction with Structural Equcation Model

    PubMed Central

    Park, Young Il

    2016-01-01

    BACKGROUND/OBJECTIVES This research analyzes the effects of the food choices of industrial workers according to their sugar intake pattern on their job satisfaction through the construction of a model on the relationship between sugar intake pattern and job satisfaction. SUBJECTS/METHODS Surveys were collected from May to July 2015. A statistical analysis of the 775 surveys from Kyungsangnam-do was conducted using SPSS13.0 for Windows and SEM was performed using the AMOS 5.0 statistics package. RESULTS The reliability of the data was confirmed by an exploratory factor analysis through a Cronbach's alpha coefficient, and the measurement model was proven to be appropriate by a confirmatory factor analysis in conjunction with AMOS. The results of factor analysis on food choice, sugar intake pattern and job satisfaction were categorized into five categories. The reliability of these findings was supported by a Cronbach's alpha coefficient of 0.6 and higher for all factors except confection (0.516) and dairy products (0.570). The multicollinearity results did not indicate a problem between the variables since the highest correlation coefficient was 0.494 (P < 0.01). In an attempt to study the sugar intake pattern in accordance with the food choices and job satisfaction of industrial workers, a structural equation model was constructed and analyzed. CONCLUSIONS All tests confirmed that the model satisfied the recommended levels for the goodness of fit index, and thus, the overall research model was proven to be appropriate. PMID:27478555

  3. Mimicry and eavesdropping enable a new form of social parasitism in ants.

    PubMed

    Powell, Scott; Del-Claro, Kleber; Feitosa, Rodrigo M; Brandão, Carlos Roberto F

    2014-10-01

    Social parasitism is defined by the exploitation of the social mechanisms of one society by another whole society. Here, we use quantitative ecological data and experiments to identify the components of a new form of social parasitism by the recently discovered "mirror turtle ant," Cephalotes specularis. We show that C. specularis workers visually mimic and actively avoid contact with foragers of the hyperaggressive host ant Crematogaster ampla, allowing them to move freely in the extensive and otherwise defended foraging networks of host colonies. Workers from parasite colonies have immediate access to these networks by nesting exclusively within host territories, and 89% of all potential host territories were parasitized. Inside the network, parasite workers eavesdrop on the host's trail pheromones to locate and exploit food resources that are defended by the host to the exclusion of all other ants. Experiments demonstrated the unprecedented capacity of the parasite for superior foraging performance on its host's pheromone trails than on trails of its own. Considered together, the apparent Batesian-Wallacian mimicry, pheromone-based interceptive eavesdropping, kleptoparasitism, and xenobiotic nesting ecology displayed by C. specularis within the territory and foraging network of a host ant represents a novel adaptive syndrome for social exploitation.

  4. Dynamics of an ant-ant Obligate Mutualism: Colony Growth, Density Dependence and Frequency Dependence

    USDA-ARS?s Scientific Manuscript database

    In insect societies, worker versus queen development (reproductive caste) is typically governed by environmental factors, but many Pogonomyrmex seed-harvester ants exhibit strict genetic caste determination, resulting in an obligate mutualism between two reproductively isolated lineages. Same-linea...

  5. Fast and Flexible: Argentine Ants Recruit from Nearby Trails

    PubMed Central

    Flanagan, Tatiana P.; Pinter-Wollman, Noa M.; Moses, Melanie E.; Gordon, Deborah M.

    2013-01-01

    Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources. PMID:23967129

  6. Fast and flexible: argentine ants recruit from nearby trails.

    PubMed

    Flanagan, Tatiana P; Pinter-Wollman, Noa M; Moses, Melanie E; Gordon, Deborah M

    2013-01-01

    Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  7. Hunger and malnutrition: the determinant of development: the case for Africa and its food and nutrition workers.

    PubMed

    Maletnlema, T N

    1992-08-01

    Hunger and malnutrition in Africa have been on the increase since 1960's reaching a climax in the 1980's when over 150 million people were affected by one form or another. Methods so far used to solve the problem do not seem to succeed, but the scientists and leaders in Africa could now take the opportunity to consider and act on the problem in their own way. The formation of an African food and nutrition group to work with others on the problems, could give an impetus to this kind of initiative. A call is made to all African food and nutrition workers to combine efforts to harness Africa resources, which have not been fully utilized in solving the problem.

  8. Consumers and Workers Opinions of A Proposed Cash Food System: NAS Alameda

    DTIC Science & Technology

    1975-08-01

    of the food preparation, food variety, the general dining decor, and the crowded conditions. 1Ü Unclassified SECURITY CLASSIFICATION OF THIS PAGE...Toward the Current System 6 Cl. Interview Data: Reasons for Not Attending More Often 6 C2. Interview Data: General Opinions of the Navy Food...Alternative Rations Systems survey which asked respondents about their general attitudes toward various ration systems. Specificslly, it allowed

  9. Farm Workers in the '90s: Where Do We Stand? Food First Action Alert.

    ERIC Educational Resources Information Center

    Cunningham, Shea

    During the 1980s, the rise of independent farm labor contractors and Republican labor policies led to a deterioration in the economic well-being of farmworkers and their families. Delays in the implementation of new safeguards under the Worker Protection Standards Act have resulted in continuing exposure to pesticides, causing such exposure to…

  10. Investigating the Occupational Challenges of Corner Store Workers Operating in Baltimore City Food Deserts.

    PubMed

    Ceryes, Caitlin A; Flamm, Laura; Fitzgerald, Sheila

    2017-02-01

    A qualitative pilot study was conducted in Baltimore City with the aim of documenting specific occupational safety challenges of small-scale urban retailers, or "corner store" owners. Semistructured interviews with a small sample ( n = 4) revealed significant challenges for owners and workers, and revealed potential areas for occupational health intervention.

  11. Farm Workers in the '90s: Where Do We Stand? Food First Action Alert.

    ERIC Educational Resources Information Center

    Cunningham, Shea

    During the 1980s, the rise of independent farm labor contractors and Republican labor policies led to a deterioration in the economic well-being of farmworkers and their families. Delays in the implementation of new safeguards under the Worker Protection Standards Act have resulted in continuing exposure to pesticides, causing such exposure to…

  12. [Food and nutrition safety of children under two years of age in families of landless rural workers].

    PubMed

    Lang, Regina Maria Ferreira; Almeida, Cláudia Choma Bettega; Taddei, José Augusto de Aguiar Carrazedo

    2011-07-01

    To date little is known of health, nutrition and food safety conditions of children living in rural camps and settlements. The present cross-sectional descriptive study seeks to present and discuss such conditions for children under two years of age in families of landless rural workers in the Central Western region of the State of Paraná. The study was conducted with a total of 337 children under two years of age in families living in two rural settlements and two rural camps. The main variables related with protein-energy malnutrition were assessed. Results indicated that the prevalence of protein-energy malnutrition was 4.7% in settlements and 10% in camps. Home location, home type and the possibility of producing food for private consumption were the distal variables that influenced most the nutritional status of the pediatric population analyzed. This study established that the search for nutritional and food safety must consider the right of accessing resources and proper means to produce safe and healthy foods in order to enable adequate feeding compatible with the habits and practices of the region.

  13. Food Service Worker. Instructional Modules for Food Management, Production and Services. Modules 18-34. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Tennessee Univ., Knoxville. Dept. of Vocational-Technical Education.

    These 17 teacher modules are part of a curriculum dealing with food management, production, and services that was developed for use in secondary and postsecondary vocational programs in Tennessee. Covered in the individual modules are hand cutlery, breakfast items, grain products, vegetables, salad dressing, meats, stock, soups, sauces, garnishes,…

  14. Food Service Worker. Instructional Modules for Food Management, Production and Services. Modules 18-34. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Tennessee Univ., Knoxville. Dept. of Vocational-Technical Education.

    These 17 teacher modules are part of a curriculum dealing with food management, production, and services that was developed for use in secondary and postsecondary vocational programs in Tennessee. Covered in the individual modules are hand cutlery, breakfast items, grain products, vegetables, salad dressing, meats, stock, soups, sauces, garnishes,…

  15. Food Service Worker. Instructional Modules for Food Management, Production and Services. Modules 35-52. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Tennessee Univ., Knoxville. Dept. of Vocational-Technical Education.

    These 18 teacher modules are part of a curriculum dealing with food management, production, and services that was developed for use in secondary and postsecondary vocational programs in Tennessee. Covered in the individual modules are quickbreads, pies, icings and toppings, specialty cakes, specialty desserts, yeast products, cream puff and puff…

  16. Food Service Worker. Instructional Modules for Food Management, Production and Services. Modules 35-52. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Tennessee Univ., Knoxville. Dept. of Vocational-Technical Education.

    These 18 teacher modules are part of a curriculum dealing with food management, production, and services that was developed for use in secondary and postsecondary vocational programs in Tennessee. Covered in the individual modules are quickbreads, pies, icings and toppings, specialty cakes, specialty desserts, yeast products, cream puff and puff…

  17. Prevalence and determinants of non-standard motorcycle safety helmets amongst food delivery workers in Selangor and Kuala Lumpur.

    PubMed

    Kulanthayan, S; See, Lai Git; Kaviyarasu, Y; Nor Afiah, M Z

    2012-05-01

    Almost half of the global traffic crashes involve vulnerable groups such as pedestrian, cyclists and two-wheeler users. The main objective of this study was to determine the factors that influence standard of the safety helmets used amongst food delivery workers by presence of Standard and Industrial Research Institute of Malaysia (SIRIM) certification label. A cross sectional study was conducted amongst 150 food delivery workers from fast food outlets in the vicinity of Selangor and Kuala Lumpur. During observation, safety helmets were classified as standard safety helmet in the presence of SIRIM label and non-standard in the absence of the label. They were approached for questionnaire participation once consent was obtained and were requested to exchange their safety helmet voluntarily with a new one after the interview. Data analysis was carried out using SPSS. Chi square and logistic regression analysis was applied to determine the significance and odds ratio of the variables studied, respectively (penetration test, age, education level, knowledge, crash history, types of safety helmet, marital status and years of riding experience) against the presence of SIRIM label. The response rate for this study was 85.2%. The prevalence of non-standard helmets use amongst fast food delivery workers was 55.3%. Safety helmets that failed the penetration test had higher odds of being non-standard helmets compared with safety helmets passing the test. Types of safety helmet indicated half-shell safety helmets had higher odds to be non-standard safety helmets compared to full-shell safety helmets. Riders with more years of riding experience were in high odds of wearing non-standard safety helmets compared to riders with less riding experience. Non-standard (non-SIRIM approved) helmets were more likely to be half-shell helmets, were more likely to fail the standards penetration test, and were more likely to be worn by older, more experienced riders. The implications of these

  18. Roles for Schools and School Social Workers in Improving Child Food Security

    ERIC Educational Resources Information Center

    Fram, Maryah Stella; Frongillo, Edward A.; Fishbein, Eliza M.; Burke, Michael P.

    2014-01-01

    Food insecurity is associated with a range of child developmental, behavioral, and emotional challenges, all of which can inhibit a child's school success. Schools offer a number of formal and informal services aimed at reducing food insecurity, but the problems associated with identifying children in need, addressing issues of stigma, and…

  19. Roles for Schools and School Social Workers in Improving Child Food Security

    ERIC Educational Resources Information Center

    Fram, Maryah Stella; Frongillo, Edward A.; Fishbein, Eliza M.; Burke, Michael P.

    2014-01-01

    Food insecurity is associated with a range of child developmental, behavioral, and emotional challenges, all of which can inhibit a child's school success. Schools offer a number of formal and informal services aimed at reducing food insecurity, but the problems associated with identifying children in need, addressing issues of stigma, and…

  20. Chemical basis of the synergism and antagonism in microbial communities in the nests of leaf-cutting ants.

    PubMed

    Schoenian, Ilka; Spiteller, Michael; Ghaste, Manoj; Wirth, Rainer; Herz, Hubert; Spiteller, Dieter

    2011-02-01

    Leaf-cutting ants cultivate the fungus Leucoagaricus gongylophorus, which serves as a major food source. This symbiosis is threatened by microbial pathogens that can severely infect L. gongylophorus. Microbial symbionts of leaf-cutting ants, mainly Pseudonocardia and Streptomyces, support the ants in defending their fungus gardens against infections by supplying antimicrobial and antifungal compounds. The ecological role of microorganisms in the nests of leaf-cutting ants can only be addressed in detail if their secondary metabolites are known. Here, we use an approach for the rapid identification of established bioactive compounds from microorganisms in ecological contexts by combining phylogenetic data, database searches, and liquid chromatography electrospray ionisation high resolution mass spectrometry (LC-ESI-HR-MS) screening. Antimycins A(1)-A(4), valinomycins, and actinomycins were identified in this manner from Streptomyces symbionts of leaf-cutting ants. Matrix-assisted laser desorption ionization (MALDI) imaging revealed the distribution of valinomycin directly on the integument of Acromyrmex echinatior workers. Valinomycins and actinomycins were also directly identified in samples from the waste of A. echinatior and A. niger leaf-cutting ants, suggesting that the compounds exert their antimicrobial and antifungal potential in the nests of leaf-cutting ants. Strong synergistic effects of the secondary meta-bolites produced by ant-associated Streptomyces were observed in the agar diffusion assay against Escovopsis weberi. Actinomycins strongly inhibit soil bacteria as well as other Streptomyces and Pseudonocardia symbionts. The antifungal antimycins are not only active against pathogenic fungi but also the garden fungus L. gongylophorus itself. In conclusion, secondary metabolites of microbial symbionts of leaf-cutting ants contribute to shaping the microbial communities within the nests of leaf-cutting ants.

  1. Association between frequency of fried food consumption and resilience to depression in Japanese company workers: a cross-sectional study.

    PubMed

    Yoshikawa, Eisho; Nishi, Daisuke; Matsuoka, Yutaka J

    2016-09-15

    Long-chain n-3 and n-6 polyunsaturated fatty acids (LC n-3/n-6 PUFA) play important roles in emotional regulation. We previously reported an association between fish consumption, which is major source of LC n-3 PUFA, and resilience to depression, where resilience is the ability to cope with stress in the face of adversity. Although the traditional Japanese dietary pattern of high fish consumption is associated with low depressive symptoms, the current Japanese diet pattern has become westernized. Westernized diets contain excessive amounts of LC n-6 PUFA due to high intake of vegetable oils commonly used in fried food and are associated with risk of depression. The aim of this study was to examine the association between frequency of fried food consumption and resilience to depression. Participants were 715 Japanese company workers. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to measure depressive symptoms, and the 14-item Resilience Scale (RS-14) was used to measure resilience. Frequency of fish and fried food consumption was assessed using a self-report questionnaire based on the Food Frequency Questionnaire. Regression analyses using Preacher and Hayes' bootstrap script were used to adjust for demographic factors, frequency of physical exercise, and fish consumption. Significant associations were identified between frequency of fried food consumption and total CES-D score (path c, B = 0.72; P < 0.01), between frequency of fried food consumption and total RS-14 score (path a, B = -1.73, P < 0.01), and between total RS-14 score and CES-D score (path b, B = -0.35; P < 0.01). The association between fried food consumption and total CES-D score was not significant when we controlled for RS-14 score. Bootstrapping results showed that there was a significant positive indirect association between frequency of fried food and CESD score through RS-14 (95 % bias-corrected and accelerated confidence interval = 0.34 to

  2. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants

    DOE PAGES

    Hooper-Bui, L. M.; Kwok, E S.C.; Buchholz, B. A.; ...

    2015-07-03

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), butmore » dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). Moreover, the distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. The bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.« less

  3. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants

    SciTech Connect

    Hooper-Bui, L. M.; Kwok, E S.C.; Buchholz, B. A.; Rust, M. K.; Eastmond, D. A.; Vogel, J. S.

    2015-07-03

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). Moreover, the distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. The bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  4. Insecticide transfer efficiency and lethal load in Argentine ants

    NASA Astrophysics Data System (ADS)

    Hooper-Bui, L. M.; Kwok, E. S. C.; Buchholz, B. A.; Rust, M. K.; Eastmond, D. A.; Vogel, J. S.

    2015-10-01

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  5. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants

    PubMed Central

    Hooper-Bui, L.M.; Kwok, E.S.C.; Buchholz, B.A.; Rust, M.K.; Eastmond, D.A.; Vogel, J.S.

    2015-01-01

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony. PMID:26504258

  6. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants.

    PubMed

    Hooper-Bui, L M; Kwok, E S C; Buchholz, B A; Rust, M K; Eastmond, D A; Vogel, J S

    2015-10-15

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of (14)C-sucrose, (14)C-hydramethylnon, and (14)C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  7. Experimental Study of the Dynamics of Foraging Ants

    NASA Astrophysics Data System (ADS)

    Walker, J. I.; Fetzner, R. P.; Baxter, G. W.

    2006-03-01

    We study the search paths of foraging ants in order to describe their behavior mathematically. Ants have become popular as simple agents in models of artificial life. Here, the ant is presented the problem of finding food when no food cues are present. In this experiment, individual ants (Formicinae lasius flavus) are allowed to forage on a two-dimensional textured surface in the absence of a food source. The position of the ant as a function of time is determined with a high resolution digital camera. The scaling properties of the resulting foraging paths compare favorably with those of certain types of random walk.

  8. Norovirus GII.17 Outbreak Linked to an Infected Post-Symptomatic Food Worker in a French Military Unit Located in France.

    PubMed

    Sanchez, Marc-Antoine; Corcostégui, Simon-Pierre; De Broucker, Charles-Arnaud; Cabre, Olivier; Watier-Grillot, Stéphanie; Perelle, Sylvie; Ambert-Balay, Katia; Pommier de Santi, Vincent

    2017-06-01

    In February 2016, an outbreak of gastroenteritis occurred in a French military unit located in Poitiers, France. Attack rate was of 34% (103/300). A case-control study identified association between illness and cake consumption. Stool samples were tested positive for Norovirus GII.17 for one patient and one post-symptomatic food worker (FW). The FW presented vomiting one day before cake preparation. The NoV strain was probably spread through food worker hand contact. Prevention of Norovirus foodborne outbreaks implies new guidelines for FWs management in France and Europe.

  9. The interplay between maze complexity, colony size, learning and memory in ants while solving a maze: A test at the colony level.

    PubMed

    Saar, Maya; Gilad, Tomer; Kilon-Kallner, Tal; Rosenfeld, Adar; Subach, Aziz; Scharf, Inon

    2017-01-01

    Central-place foragers need to explore their immediate habitat in order to reach food. We let colonies of the individually foraging desert ant Cataglyphis niger search for a food reward in a maze. We did so for three tests per day over two successive days and an additional test after a time interval of 4-20 days (seven tests in total). We examined whether the colonies reached the food reward faster, consumed more food and changed the number of workers searching over time, within and between days. Colonies' food-discovery time shortened within and between days, indicating that some workers learnt and became more efficient in moving through the maze. Such workers, however, also forgot and deteriorated in their food-discovery time, leveling off back to initial performance after about two weeks. We used mazes of increasing complexity levels, differing in the potential number of wrong turns. The number of workers searching increased with colony size. Food-discovery time also increased with colony size in complex mazes but not in simple ones, perhaps due to the more frequent interactions among workers in large colonies having to move through narrow routes. Finally, the motivation to solve the maze was probably not only the food reward, because food consumption did not change over time.

  10. Consumer and Worker Evaluation of Cash Food Systems: Loring Air Force Base Part 1

    DTIC Science & Technology

    1975-11-01

    things the customer wanted. Second, it gave the airmen an opportunity to save money. And, third, it reportedly created less food waste . (See Appendix... food waste , a problem BAS/A La Carte reportedly reduced at Shaw AFB. In agreement with these U ■■»»T?OT?r?gp«^g’fCT’"w»i>g«»T^^^ Table 11... Food Waste 4(?) 1(6) 2(4) 3(13) 10(8) Decreased Food Expense 1(2) 0 2(4) 0 3(2) 0 Allj o o ä«O 35 ■ ■ ■ Table 12 Frequency (and

  11. From Kitchen Peelings to Spill the Beans: Empowering NESB Workers at P&O Prepared Foods.

    ERIC Educational Resources Information Center

    O'Brien, Paula

    1996-01-01

    A workplace education program was devised for volunteer employees from non-English-speaking backgrounds (NESB) at a food processing plant in Brisbane, Australia. Changing work conditions resulted in increased demands upon employees' language and literacy skills. (Author/JOW)

  12. An ants-eye view of an ant-plant protection mutualism

    PubMed Central

    Lanan, M. C.; Bronstein, J. L.

    2013-01-01

    Ant protection of extrafloral nectar-secreting plants (EFN plants) is a common form of mutualism found in most habitats around the world. However, very few studies have considered these mutualisms from the ant, rather than the plant, perspective. In particular, a whole-colony perspective that takes into account the spatial structure and nest arrangement of the ant colonies that visit these plants has been lacking, obscuring when and how colony-level foraging decisions might affect tending rates on individual plants. Here, we experimentally demonstrate that recruitment of Crematogaster opuntiae (Buren) ant workers to the extrafloral nectar-secreting cactus Ferocactus wislizeni (Englem) is not independent between plants up to 5m apart. Colony territories of C. opuntiae are large, covering areas of up to 5000m2, and workers visit between five and thirty-four extrafloral nectar-secreting barrel cacti within the territories. These ants are highly polydomous, with up to twenty nest entrances dispersed throughout the territory and interconnected by trail networks. Our study demonstrates that worker recruitment is not independent within large polydomous ant colonies, highlighting the importance of considering colonies rather than individual workers as the relevant study unit within ant/plant protection mutualisms PMID:23515612

  13. An ant's-eye view of an ant-plant protection mutualism.

    PubMed

    Lanan, M C; Bronstein, J L

    2013-07-01

    Ant protection of extrafloral nectar (EFN)-secreting plants is a common form of mutualism found in most habitats around the world. However, very few studies have considered these mutualisms from the ant, rather than the plant, perspective. In particular, a whole-colony perspective that takes into account the spatial structure and nest arrangement of the ant colonies that visit these plants has been lacking, obscuring when and how colony-level foraging decisions might affect tending rates on individual plants. Here, we experimentally demonstrate that recruitment of Crematogaster opuntiae (Buren) ant workers to the EFN-secreting cactus Ferocactus wislizeni (Englem) is not independent between plants up to 5 m apart. Colony territories of C. opuntiae are large, covering areas of up to 5,000 m(2), and workers visit between five and 34 EFN-secreting barrel cacti within the territories. These ants are highly polydomous, with up to 20 nest entrances dispersed throughout the territory and interconnected by trail networks. Our study demonstrates that worker recruitment is not independent within large polydomous ant colonies, highlighting the importance of considering colonies rather than individual workers as the relevant study unit within ant/plant protection mutualisms.

  14. Effect of primer pheromones and pollen diet on the food producing glands of worker honey bees (Apis mellifera L.).

    PubMed

    Peters, Lizette; Zhu-Salzman, Keyan; Pankiw, Tanya

    2010-02-01

    Cooperative brood care is highly developed in the honey bee such that workers called nurses use their hypopharyngeal and mandibular glands to biosynthesize proteinaceous secretions that are progressively provisioned to larvae. The role that honey bee primer pheromones play in the functional physiology of food producing glands was examined. The combined and separate effects of queen mandibular pheromone (QMP) and brood pheromone (BP) on amount of protein extractable from hypopharyngeal and mandibular glands of workers reared for 12 days with and without pollen diets was measured. In rearing environments with a pollen diet, BP, and QMP+BP pheromone treatments significantly increased extractable protein from both glands. Bees reared with QMP+pollen had amounts of protein extractable from both glands that were not significantly different from control bees (no pheromones, no pollen). Pollen in the diet alone significantly increased amounts of protein extractable from glands versus control. In rearing environments without pollen, QMP+BP had a synergizing effect on amount of protein in both glands. The QMP+BP treatment was the only rearing environment without a pollen diet where protein amounts were significantly greater than the control. The synergizing effect of QMP+BP on extractable mandibular and hypopharyngeal gland protein suggests a highly derived role for the combined effect of these two primer pheromones on honey bee cooperative brood care. Mandibular gland area was significantly and positively correlated with extractable protein. Amounts of extractable protein from both glands declined significantly with age of workers in all treatments. However, treatment significantly affected rate of decline. The adaptive significance of gland protein amounts in response to pheromones and pollen diet are discussed. Copyright 2009 Elsevier Ltd. All rights reserved.

  15. Ants on plants: a meta-analysis of the role of ants as plant biotic defenses.

    PubMed

    Rosumek, Felix B; Silveira, Fernando A O; de S Neves, Frederico; de U Barbosa, Newton P; Diniz, Livia; Oki, Yumi; Pezzini, Flavia; Fernandes, G Wilson; Cornelissen, Tatiana

    2009-06-01

    We reviewed the evidence on the role of ants as plant biotic defenses, by conducting meta-analyses for the effects of experimental removal of ants on plant herbivory and fitness with data pooled from 81 studies. Effects reviewed were plant herbivory, herbivore abundance, hemipteran abundance, predator abundance, plant biomass and reproduction in studies where ants were experimentally removed (n = 273 independent comparisons). Ant removal exhibited strong effects on herbivory rates, as plants without ants suffered almost twice as much damage and exhibited 50% more herbivores than plants with ants. Ants also influenced several parameters of plant fitness, as plants without ants suffered a reduction in biomass (-23.7%), leaf production (-51.8%), and reproduction (-24.3%). Effects were much stronger in tropical regions compared to temperate ones. Tropical plants suffered almost threefold higher herbivore damage than plants from temperate regions and exhibited three times more herbivores. Ant removal in tropical plants resulted in a decrease in plant fitness of about 59%, whereas in temperate plants this reduction was not statistically significant. Ant removal effects were also more important in obligate ant-plants (=myrmecophytes) compared to plants exhibiting facultative relationships with hemiptera or those plants with extrafloral nectaries and food bodies. When only tropical plants were considered and the strength of the association between ants and plants taken into account, plants with obligate association with ants exhibited almost four times higher herbivory compared to plants with facultative associations with ants, but similar reductions in plant reproduction. The removal of a single ant species increased plant herbivory by almost three times compared to the removal of several ant species. Altogether, these results suggest that ants do act as plant biotic defenses, but the effects of their presence are more pronounced in tropical systems, especially in

  16. Multi-Phase Defense by the Big-Headed Ant, Pheidole obtusospinosa, Against Raiding Army Ants

    PubMed Central

    Huang, Ming H.

    2010-01-01

    Army ants are well known for their destructive raids of other ant colonies. Some known defensive strategies include nest evacuation, modification of nest architecture, blockade of nest entrances using rocks or debris, and direct combat outside the nest. Since army ants highly prefer Pheidole ants as prey in desert habitats, there may be strong selective pressure on Pheidole to evolve defensive strategies to better survive raids. In the case of P. obtusospinosa Pergande (Hymenoptera: Formicidae), the worker caste system includes super majors in addition to smaller majors and minor workers. Interestingly, P. obtusospinosa and the six other New World Pheidole species described to have polymorphic major workers are all found in the desert southwest and adjacent regions of Mexico, all co-occurring with various species of Neivamyrmex army ants. Pheidole obtusospinosa used a multi-phase defensive strategy against army ant raids that involved their largest major workers. During army ant attacks, these super majors were involved in blocking the nest entrance with their enlarged heads. This is the first description of defensive head-blocking by an ant species that lacks highly modified head morphology, such as a truncated or disc-shaped head. P. obtusospinosa super majors switched effectively between passive headblocking at the nest entrance and aggressive combat outside the nest. If this multi-phase strategy is found to be used by other Pheidole species with polymorphic majors in future studies, it is possible that selective pressure by army ant raids may have been partially responsible for the convergent evolution of this extra worker caste. PMID:20569122

  17. More than royal food - Major royal jelly protein genes in sexuals and workers of the honeybee Apis mellifera

    PubMed Central

    2013-01-01

    Background In the honeybee Apis mellifera, female larvae destined to become a queen are fed with royal jelly, a secretion of the hypopharyngeal glands of young nurse bees that rear the brood. The protein moiety of royal jelly comprises mostly major royal jelly proteins (MRJPs) of which the coding genes (mrjp1-9) have been identified on chromosome 11 in the honeybee’s genome. Results We determined the expression of mrjp1-9 among the honeybee worker caste (nurses, foragers) and the sexuals (queens (unmated, mated) and drones) in various body parts (head, thorax, abdomen). Specific mrjp expression was not only found in brood rearing nurse bees, but also in foragers and the sexuals. Conclusions The expression of mrjp1 to 7 is characteristic for the heads of worker bees, with an elevated expression of mrjp1-4 and 7 in nurse bees compared to foragers. Mrjp5 and 6 were higher in foragers compared to nurses suggesting functions in addition to those of brood food proteins. Furthermore, the expression of mrjp9 was high in the heads, thoraces and abdomen of almost all female bees, suggesting a function irrespective of body section. This completely different expression profile suggests mrjp9 to code for the most ancestral major royal jelly protein of the honeybee. PMID:24279675

  18. Selective isolation of dematiaceous fungi from the workers of Atta laevigata (Formicidae: Attini).

    PubMed

    Guedes, F L A; Attili-Angelis, D; Pagnocca, F C

    2012-01-01

    Leaf-cutting ants (Formicidae: Attini) are considered pests in agriculture for their impact in human crops, as they utilize leaf fragments to raise their fungal mutualist (Agaricales: Lepiotaceae). Basically, the basidiomycetous fungus is cultivated to supply food to adult workers and broads; in return, the ants protect it against natural enemies. However, recent studies have claimed that other microorganisms are associated to ant nests where a wide range of interactions may take place. To investigate the occurrence of dematiaceous fungi on the cuticle of Atta laevigata ants, 30 workers were sampled from an adult nest located in the surroundings of the Center for the Studies of Social Insects, UNESP-Rio Claro, SP, Brazil. The use of selective techniques to avoid high-sporulation fungi has been recommended and was tested in this study. To favor the isolation of the desired fungi, heads and cuticle scrapings of ant bodies were inoculated on Mycosel agar and incubated for 3 weeks at 35°C. Morphological and molecular methods were used to identify the filamentous fungi recovered. From 56 isolates, 19 were hyaline filamentous species, and among the remaining 37, some are mentioned as phyto-associated fungi like Alternaria arborescens, Bipolaris sorokiniana, Bipolaris eleusines, Bipolaris zeae, Curvularia trifolii, and Paraphaeosphaeria michotii. These species are reported from A. laevigata bodies for the first time. None of the isolation trials revealed the presence of the parasite Escovopsis or entomopathogenic fungi. The possible spread of the fungi in nature by the ants is discussed.

  19. Paralyzing action from a distance in an arboreal African ant species.

    PubMed

    Rifflet, Aline; Tene, Nathan; Orivel, Jerome; Treilhou, Michel; Dejean, Alain; Vetillard, Angelique

    2011-01-01

    Due to their prowess in interspecific competition and ability to catch a wide range of arthropod prey (mostly termites with which they are engaged in an evolutionary arms race), ants are recognized as a good model for studying the chemicals involved in defensive and predatory behaviors. Ants' wide diversity of nesting habits and relationships with plants and prey types implies that these chemicals are also very diverse. Using the African myrmicine ant Crematogaster striatula as our focal species, we adopted a three-pronged research approach. We studied the aggressive and predatory behaviors of the ant workers, conducted bioassays on the effect of their Dufour gland contents on termites, and analyzed these contents. (1) The workers defend themselves or eliminate termites by orienting their abdominal tip toward the opponent, stinger protruded. The chemicals emitted, apparently volatile, trigger the recruitment of nestmates situated in the vicinity and act without the stinger having to come into direct contact with the opponent. Whereas alien ants competing with C. striatula for sugary food sources are repelled by this behavior and retreat further and further away, termites defend their nest whatever the danger. They face down C. striatula workers and end up by rolling onto their backs, their legs batting the air. (2) The bioassays showed that the toxicity of the Dufour gland contents acts in a time-dependent manner, leading to the irreversible paralysis, and, ultimately, death of the termites. (3) Gas chromatography-mass spectrometry analyses showed that the Dufour gland contains a mixture of mono- or polyunsaturated long-chain derivatives, bearing functional groups like oxo-alcohols or oxo-acetates. Electrospray ionization-mass spectrometry showed the presence of a molecule of 1584 Da that might be a large, acetylated alkaloid capable of splitting into smaller molecules that could be responsible for the final degree of venom toxicity.

  20. Paralyzing Action from a Distance in an Arboreal African Ant Species

    PubMed Central

    Rifflet, Aline; Tene, Nathan; Orivel, Jerome; Treilhou, Michel; Dejean, Alain; Vetillard, Angelique

    2011-01-01

    Due to their prowess in interspecific competition and ability to catch a wide range of arthropod prey (mostly termites with which they are engaged in an evolutionary arms race), ants are recognized as a good model for studying the chemicals involved in defensive and predatory behaviors. Ants' wide diversity of nesting habits and relationships with plants and prey types implies that these chemicals are also very diverse. Using the African myrmicine ant Crematogaster striatula as our focal species, we adopted a three-pronged research approach. We studied the aggressive and predatory behaviors of the ant workers, conducted bioassays on the effect of their Dufour gland contents on termites, and analyzed these contents. (1) The workers defend themselves or eliminate termites by orienting their abdominal tip toward the opponent, stinger protruded. The chemicals emitted, apparently volatile, trigger the recruitment of nestmates situated in the vicinity and act without the stinger having to come into direct contact with the opponent. Whereas alien ants competing with C. striatula for sugary food sources are repelled by this behavior and retreat further and further away, termites defend their nest whatever the danger. They face down C. striatula workers and end up by rolling onto their backs, their legs batting the air. (2) The bioassays showed that the toxicity of the Dufour gland contents acts in a time-dependent manner, leading to the irreversible paralysis, and, ultimately, death of the termites. (3) Gas chromatography-mass spectrometry analyses showed that the Dufour gland contains a mixture of mono- or polyunsaturated long-chain derivatives, bearing functional groups like oxo-alcohols or oxo-acetates. Electrospray ionization-mass spectrometry showed the presence of a molecule of 1584 Da that might be a large, acetylated alkaloid capable of splitting into smaller molecules that could be responsible for the final degree of venom toxicity. PMID:22194854

  1. The role of symbiont genetic distance and potential adaptability in host preference towards Pseudonocardia symbionts in Acromyrmex leaf-cutting ants.

    PubMed

    Poulsen, Michael; Maynard, Janielle; Roland, Damien L; Currie, Cameron R

    2011-01-01

    Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales), help defend the ants' fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony-founding queens. A recent report found that Acromyrmex workers are able to differentiate between their native Pseudonocardia strain and non-native strains isolated from sympatric or allopatric Acromyrmex species, and show preference for their native strain. Here we explore worker preference when presented with two non-native strains, elucidating the role of genetic distance on preference between strains and Pseudonocardia origin. Our findings suggest that ants tend to prefer bacteria more closely related to their native bacterium and that genetic similarity is probably more important than whether symbionts are ant-associated or free-living. Preliminary findings suggest that when continued exposure to a novel Pseudonocardia strain occurs, ant symbiont preference is potentially adaptable, with colonies apparently being able to alter symbiont preference over time. These findings are discussed in relation to the role of adaptive recognition, potential ecological flexibility in symbiont preference, and more broadly, in relation to self versus non-self recognition.

  2. The Role of Symbiont Genetic Distance and Potential Adaptability in Host Preference Towards Pseudonocardia Symbionts in Acromyrmex Leaf-Cutting Ants

    PubMed Central

    Poulsen, Michael; Maynard, Janielle; Roland, Damien L; Currie, Cameron R

    2011-01-01

    Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales), help defend the ants' fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony-founding queens. A recent report found that Acromyrmex workers are able to differentiate between their native Pseudonocardia strain and non-native strains isolated from sympatric or allopatric Acromyrmex species, and show preference for their native strain. Here we explore worker preference when presented with two non-native strains, elucidating the role of genetic distance on preference between strains and Pseudonocardia origin. Our findings suggest that ants tend to prefer bacteria more closely related to their native bacterium and that genetic similarity is probably more important than whether symbionts are ant-associated or free-living. Preliminary findings suggest that when continued exposure to a novel Pseudonocardia strain occurs, ant symbiont preference is potentially adaptable, with colonies apparently being able to alter symbiont preference over time. These findings are discussed in relation to the role of adaptive recognition, potential ecological flexibility in symbiont preference, and more broadly, in relation to self versus non-self recognition. PMID:22225537

  3. Tandem carrying, a new foraging strategy in ants: description, function, and adaptive significance relative to other described foraging strategies

    NASA Astrophysics Data System (ADS)

    Guénard, Benoit; Silverman, Jules

    2011-08-01

    An important aspect of social insect biology lies in the expression of collective foraging strategies developed to exploit food. In ants, four main types of foraging strategies are typically recognized based on the intensity of recruitment and the importance of chemical communication. Here, we describe a new type of foraging strategy, "tandem carrying", which is also one of the most simple recruitment strategies, observed in the Ponerinae species Pachycondyla chinensis. Within this strategy, workers are directly carried individually and then released on the food resource by a successful scout. We demonstrate that this recruitment is context dependent and based on the type of food discovered and can be quickly adjusted as food quality changes. We did not detect trail marking by tandem-carrying workers. We conclude by discussing the importance of tandem carrying in an evolutionary context relative to other modes of recruitment in foraging and nest emigration.

  4. Conflict resolution in an ant-plant interaction: Acacia constricta traits reduce ant costs to reproduction.

    PubMed

    Nicklen, E Fleur; Wagner, Diane

    2006-05-01

    Many plant species attract ants onto their foliage with food rewards or nesting space. However, ants can interfere with plant reproduction when they visit flowers. This study tests whether Acacia constricta separates visiting ant species temporally or spatially from newly opened inflorescences and pollinators. The diurnal activity patterns of ants and A. constricta pollinators peaked at different times of day, and the activity of pollinators followed the daily dehiscence of A. constricta inflorescences. In addition to being largely temporally separated, ants rarely visited open inflorescences. A floral ant repellent contributes to the spatial separation of ants and inflorescences. In a field experiment, ants of four species were given equal access to inflorescences in different developmental stages. On average, the frequency with which ants made initial, antennal contact with the floral stages did not differ, but ants significantly avoided secondary contact with newly opened inflorescences relative to buds and old inflorescences, and old inflorescences relative to buds. Ants also avoided contact with pollen alone, indicating that pollen is at least one source of the repellent. The results suggest A. constricta has effectively resolved the potential conflict between visiting ants and plant reproduction.

  5. The Ants Have It!

    ERIC Educational Resources Information Center

    Daugherty, Belinda

    2001-01-01

    Uses the GEMS guide, "Ants at Home Underground", to explore the life of ants and teach about them in a classroom setting. The activity applies students' knowledge of ants and students learn about ant colonies, what ants eat, and how they live. (SAH)

  6. The Ants Have It!

    ERIC Educational Resources Information Center

    Daugherty, Belinda

    2001-01-01

    Uses the GEMS guide, "Ants at Home Underground", to explore the life of ants and teach about them in a classroom setting. The activity applies students' knowledge of ants and students learn about ant colonies, what ants eat, and how they live. (SAH)

  7. Ants defend aphids against lethal disease.

    PubMed

    Nielsen, Charlotte; Agrawal, Anurag A; Hajek, Ann E

    2010-04-23

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies.

  8. Ants defend aphids against lethal disease

    PubMed Central

    Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

    2010-01-01

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  9. Niches and coexistence of ant communities in Puerto Rico

    Treesearch

    J.A. Torres

    1984-01-01

    I studied ant coexistence in adjacent areas of upland tropical forest, grassland, and agricultural land in San Lorenzo, Puerto Rico. Data on food utilization, daily activity, nesting sites, microhabitat utilization and interspecific aggression were collected. Ants' tolerance to 45 degree C was determined in the laboratory. Agricultural and grassland ants eat grain...

  10. A Novel delivery Method for Ant (Hymenoptera: Formicidae) toxicants

    USDA-ARS?s Scientific Manuscript database

    Described here is a new delivery method for ant toxicants consisting of an inert carrier, an attractant, and a toxicant. Unlike baits, this system does not contain a food source, but uses ant to ant contact rather than trophallaxis as the mechanism for horizontal dispersal of the toxicant through th...

  11. Ants use odour cues to exploit fig-fig wasp interactions

    NASA Astrophysics Data System (ADS)

    Schatz, Bertrand; Hossaert-McKey, Martine

    2010-01-01

    Fig wasps may constitute a relatively abundant food source for ants associated with the fig-fig wasp nursery pollination mutualism. We found previously that a Mediterranean ant species detects fig wasps by chemical signals. In this paper we want to test the generality of this finding by studying two tropical ants, Oecophylla smaragdina and Crematogaster sp., preying on fig wasps on the dioecious Ficus fistulosa in Brunei (Borneo). Behavioural tests in a Y-tube olfactometer showed that these two ants were attracted both to odours emitted by receptive figs and to those emitted by fig wasps (male and female of the pollinator, and a non-pollinating fig wasp) used here as a kairomone. Naïve workers were not attracted to fig wasps, suggesting that olfactory learning may play a role in prey detection. We also found that O. smaragdina was much more likely to be present on figs of male trees (where fig wasps are more abundant), and that the abundance of this ant species varied strongly with developmental phase of figs on individual trees. Moreover, its aggressiveness was also strongly influenced by the nature of the object presented in our behavioural tests, the site of the test and the developmental phase of the fig tested. Investigation on the chemical and behavioural ecology of the different interacting species provides important insights into the intricate relationships supported by the fig-fig wasp mutualism.

  12. Ants swimming in pitcher plants: kinematics of aquatic and terrestrial locomotion in Camponotus schmitzi.

    PubMed

    Bohn, Holger Florian; Thornham, Daniel George; Federle, Walter

    2012-06-01

    Camponotus schmitzi ants live in symbiosis with the Bornean pitcher plant Nepenthes bicalcarata. Unique among ants, the workers regularly dive and swim in the pitcher's digestive fluid to forage for food. High-speed motion analysis revealed that C. schmitzi ants swim at the surface with all legs submerged, with an alternating tripod pattern. Compared to running, swimming involves lower stepping frequencies and larger phase delays within the legs of each tripod. Swimming ants move front and middle legs faster and keep them more extended during the power stroke than during the return stroke. Thrust estimates calculated from three-dimensional leg kinematics using a blade-element approach confirmed that forward propulsion is mainly achieved by the front and middle legs. The hind legs move much less, suggesting that they mainly serve for steering. Experiments with tethered C. schmitzi ants showed that characteristic swimming movements can be triggered by submersion in water. This reaction was absent in another Camponotus species investigated. Our study demonstrates how insects can use the same locomotory system and similar gait patterns for moving on land and in water. We discuss insect adaptations for aquatic/amphibious lifestyles and the special adaptations of C. schmitzi to living on an insect-trapping pitcher plant.

  13. Detection of mitochondrial COII DNA sequences in ant guts as a method for assessing termite predation by ants.

    PubMed

    Fayle, Tom M; Scholtz, Olivia; Dumbrell, Alex J; Russell, Stephen; Segar, Simon T; Eggleton, Paul

    2015-01-01

    Termites and ants contribute more to animal biomass in tropical rain forests than any other single group and perform vital ecosystem functions. Although ants prey on termites, at the community level the linkage between these groups is poorly understood. Thus, assessing the distribution and specificity of ant termitophagy is of considerable interest. We describe an approach for quantifying ant-termite food webs by sequencing termite DNA (cytochrome c oxidase subunit II, COII) from ant guts and apply this to a soil-dwelling ant community from tropical rain forest in Gabon. We extracted DNA from 215 ants from 15 species. Of these, 17.2 % of individuals had termite DNA in their guts, with BLAST analysis confirming the identity of 34.1 % of these termites to family level or better. Although ant species varied in detection of termite DNA, ranging from 63 % (5/7; Camponotus sp. 1) to 0 % (0/7; Ponera sp. 1), there was no evidence (with small sample sizes) for heterogeneity in termite consumption across ant taxa, and no evidence for species-specific ant-termite predation. In all three ant species with identifiable termite DNA in multiple individuals, multiple termite species were represented. Furthermore, the two termite species that were detected on multiple occasions in ant guts were in both cases found in multiple ant species, suggesting that ant-termite food webs are not strongly compartmentalised. However, two ant species were found to consume only Anoplotermes-group termites, indicating possible predatory specialisation at a higher taxonomic level. Using a laboratory feeding test, we were able to detect termite COII sequences in ant guts up to 2 h after feeding, indicating that our method only detects recent feeding events. Our data provide tentative support for the hypothesis that unspecialised termite predation by ants is widespread and highlight the use of molecular approaches for future studies of ant-termite food webs.

  14. Detection of Mitochondrial COII DNA Sequences in Ant Guts as a Method for Assessing Termite Predation by Ants

    PubMed Central

    Fayle, Tom M.; Scholtz, Olivia; Dumbrell, Alex J.; Russell, Stephen; Segar, Simon T.; Eggleton, Paul

    2015-01-01

    Termites and ants contribute more to animal biomass in tropical rain forests than any other single group and perform vital ecosystem functions. Although ants prey on termites, at the community level the linkage between these groups is poorly understood. Thus, assessing the distribution and specificity of ant termitophagy is of considerable interest. We describe an approach for quantifying ant-termite food webs by sequencing termite DNA (cytochrome c oxidase subunit II, COII) from ant guts and apply this to a soil-dwelling ant community from tropical rain forest in Gabon. We extracted DNA from 215 ants from 15 species. Of these, 17.2 % of individuals had termite DNA in their guts, with BLAST analysis confirming the identity of 34.1 % of these termites to family level or better. Although ant species varied in detection of termite DNA, ranging from 63 % (5/7; Camponotus sp. 1) to 0 % (0/7; Ponera sp. 1), there was no evidence (with small sample sizes) for heterogeneity in termite consumption across ant taxa, and no evidence for species-specific ant-termite predation. In all three ant species with identifiable termite DNA in multiple individuals, multiple termite species were represented. Furthermore, the two termite species that were detected on multiple occasions in ant guts were in both cases found in multiple ant species, suggesting that ant-termite food webs are not strongly compartmentalised. However, two ant species were found to consume only Anoplotermes-group termites, indicating possible predatory specialisation at a higher taxonomic level. Using a laboratory feeding test, we were able to detect termite COII sequences in ant guts up to 2 h after feeding, indicating that our method only detects recent feeding events. Our data provide tentative support for the hypothesis that unspecialised termite predation by ants is widespread and highlight the use of molecular approaches for future studies of ant-termite food webs. PMID:25853549

  15. Ant nebula

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A new Hubble Space Telescope image of a celestial object called the Ant Nebula may shed new light on the future demise of our Sun. The image is available at http://www.jpl.nasa.gov/pictures/wfpc .

    The nebula, imaged on July 20, 1997, and June 30, 1998, by Hubble's Wide Field and Planetary Camera 2, was observed by Drs. Raghvendra Sahai and John Trauger of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bruce Balick of the University of Washington in Seattle; and Vincent Icke of Leiden University in the Netherlands. JPL designed and built the camera.

    The Ant Nebula, whose technical name is Mz3, resembles the head and thorax of an ant when observed with ground-based telescopes. The new Hubble image, with 10 times the resolution revealing 100 times more detail, shows the 'ant's' body as a pair of fiery lobes protruding from a dying, Sun- like star. The Ant Nebula is located between 3,000 and 6,000 light years from Earth in the southern constellation Norma.

    The image challenges old ideas about what happens to dying stars. This observation, along with other pictures of various remnants of dying stars called planetary nebulae, shows that our Sun's fate will probably be much more interesting, complex and dramatic than astronomers previously believed.

    Although the ejection of gas from the dying star in the Ant Nebula is violent, it does not show the chaos one might expect from an ordinary explosion, but instead shows symmetrical patterns. One possibility is that the central star has a closely orbiting companion whose gravitational tidal forces shape the outflowing gas. A second possibility is that as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Electrically charged winds, much like those in our Sun's solar wind but millions of times denser and moving at speeds up to 1,000 kilometers per second (more than 600 miles per second) from the star, follow the twisted field lines on their way

  16. Ant nebula

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A new Hubble Space Telescope image of a celestial object called the Ant Nebula may shed new light on the future demise of our Sun. The image is available at http://www.jpl.nasa.gov/pictures/wfpc .

    The nebula, imaged on July 20, 1997, and June 30, 1998, by Hubble's Wide Field and Planetary Camera 2, was observed by Drs. Raghvendra Sahai and John Trauger of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bruce Balick of the University of Washington in Seattle; and Vincent Icke of Leiden University in the Netherlands. JPL designed and built the camera.

    The Ant Nebula, whose technical name is Mz3, resembles the head and thorax of an ant when observed with ground-based telescopes. The new Hubble image, with 10 times the resolution revealing 100 times more detail, shows the 'ant's' body as a pair of fiery lobes protruding from a dying, Sun- like star. The Ant Nebula is located between 3,000 and 6,000 light years from Earth in the southern constellation Norma.

    The image challenges old ideas about what happens to dying stars. This observation, along with other pictures of various remnants of dying stars called planetary nebulae, shows that our Sun's fate will probably be much more interesting, complex and dramatic than astronomers previously believed.

    Although the ejection of gas from the dying star in the Ant Nebula is violent, it does not show the chaos one might expect from an ordinary explosion, but instead shows symmetrical patterns. One possibility is that the central star has a closely orbiting companion whose gravitational tidal forces shape the outflowing gas. A second possibility is that as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Electrically charged winds, much like those in our Sun's solar wind but millions of times denser and moving at speeds up to 1,000 kilometers per second (more than 600 miles per second) from the star, follow the twisted field lines on their way

  17. Spatiotemporal chemotactic model for ant foraging

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Subramanian; Laurent, Thomas; Kumar, Manish; Bertozzi, Andrea L.

    2014-12-01

    In this paper, we present a generic theoretical chemotactic model that accounts for certain emergent behaviors observed in ant foraging. The model does not have many of the constraints and limitations of existing models for ants colony dynamics and takes into account the distinctly different behaviors exhibited in nature by ant foragers in search of food and food ferrying ants. Numerical simulations based on the model show trail formation in foraging ant colonies to be an emergent phenomenon and, in particular, replicate behavior observed in experiments involving the species P. megacephala. The results have broader implications for the study of randomness in chemotactic models. Potential applications include the developments of novel algorithms for stochastic search in engineered complex systems such as robotic swarms.

  18. To drink or grasp? How bullet ants ( Paraponera clavata) differentiate between sugars and proteins in liquids

    NASA Astrophysics Data System (ADS)

    Jandt, Jennifer; Larson, Hannah K.; Tellez, Peter; McGlynn, Terrence P.

    2013-12-01

    Flexibility in behavior can increase the likelihood that a forager may respond optimally in a fluctuating environment. Nevertheless, physiological or neuronal constraints may result in suboptimal responses to stimuli. We observed foraging workers of the giant tropical ant (also referred to as the "bullet ant"), Paraponera clavata, as they reacted to liquid solutions with varying concentrations of sugar and protein. We show that when protein/sucrose concentration is high, many bullet ants will often try to grasp at the droplet, rather than gather it by drinking. Because P. clavata actively hunt for prey, fixed action patterns and rapid responses to protein may be adaptively important, regardless of the medium in which it is presented. We conclude that, in P. clavata, food-handling decisions are made in response to the nutrient content of the food rather than the texture of the food. Further, we suggest that colonies that maintain a mixture of individuals with consistent fixed or flexible behavioral responses to food-handling decisions may be better adapted to fluctuating environmental conditions, and we propose future studies that could address this.

  19. The evolution of multiple mating in army ants.

    PubMed

    Kronauer, Daniel J C; Johnson, Robert A; Boomsma, Jacobus J

    2007-02-01

    The evolution of mating systems in eusocial Hymenoptera is constrained because females mate only during a brief period early in life, whereas inseminated queens and their stored sperm may live for decades. Considerable research effort during recent years has firmly established that obligate multiple mating has evolved only a few times: in Apis honeybees, Vespula wasps, Pogonomyrmex harvester ants, Atta and Acromyrmex leaf-cutting ants, the ant Cataglyphis cursor, and in at least some army ants. Here we provide estimates of queen-mating frequency for New World Neivamyrmex and Old World Aenictus species, which, compared to other army ants, have relatively small colonies and little size polymorphism among workers. To provide the first overall comparative analysis of the evolution of army ant mating systems, we combine these new results with previous estimates for African Dorylus and New World Eciton army ants, which have very large colonies and considerable worker polymorphism. We show that queens of Neivamyrmex and Aenictus mate with the same high numbers of males (usually ca. 10-20) as do queens of army ant species with very large colony sizes. We infer that multiple queen mating is ancestral in army ants and has evolved over 100 million years ago as part of the army ant adaptive syndrome. A comparison of army ants and honeybees suggests that mating systems in these two distantly related groups may have been convergently shaped by strikingly similar selective pressures.

  20. Salmonella serovar distribution in cobras (Naja kaouthia), snake-food species, and farm workers at Queen Saovabha Snake Park, Thailand.

    PubMed

    Prapasarakul, Nuvee; Pulsrikarn, Chaiwat; Vasaruchapong, Taksa; Lekcharoen, Pisin; Chanchaithong, Pattrarat; Lugsomya, Kittitat; Keschumras, Nitiwadee; Thanomsuksinchai, Natthakarn; Tanchiangsai, Kanittha; Tummaruk, Padet

    2012-03-01

    The purpose of the current study was to investigate the prevalence and serovar distribution of Salmonella isolates in cobras and their environment at a snake park. A total of 166 fecal or intestinal samples were examined, comprising 39 samples from captive cobras (Naja kaouthia), 70 from recently wild-caught cobras, 19 from wild-caught cobras that had been kept on the farm for over 3 months, 18 from mice (Mus musculus), 12 from frogs (Hoplobatrachus rugulosus), and 8 from farm workers. Specific serological identification was performed, and pulsed-field gel electrophoresis (PFGE) was utilized for DNA analysis. Out of all snakes (n = 128), 20 of the 30 animals used for snake food and 3 of the 8 samples from personnel were positive for Salmonella spp. There were 228 Salmonella isolates, with a total of 29 serovars from subspecies I and IIIb, composed of 24 serovars from cobras and 5 from the other sources. Salmonella Amsterdam was predominant in captive-born and captive cobras, followed by S. Poona and S. Bareilly, respectively (P < 0.05). Salmonella I 4,[5],12:i:- was the sole serovar detected from the mice, while 3 serovars including Ramatgan, I 4,[5],12:e,h:-, and rough strain were detected only from frogs (P < 0.001). Salmonella Derby was only detected in workers. On the basis of the PFGE results, evidence of movement of isolates between human beings and snakes, and between snakes and frogs, was found for S. Poona and S. Wandsworth, respectively. The study suggests that Salmonella spp. act as true residents in the intestinal tract of cobras with high risk of environmental contamination through fecal shedding.

  1. Melissotarsus ants are likely able to digest plant polysaccharides.

    PubMed

    Mony, Ruth; Dejean, Alain; Bilong, Charles Félix Bilong; Kenne, Martin; Rouland-Lefèvre, Corinne

    2013-10-01

    Melissotarsus ants have an extremely specialized set of behaviours. Both workers and gynes tunnel galleries in their host tree bark. Workers walk with their mesothoracic legs pointing upwards and tend Diaspididae hemiptera for their flesh. The ants use their forelegs to plug the galleries with silk that they secrete themselves. We hypothesised that the ants' energetic needs for nearly constant gallery digging could be satisfied through the absorption of host tree tissues; so, using basic techniques, we examined the digestive capacities of workers from two species. We show that workers are able to degrade oligosaccharides and heterosides as well as, to a lesser degree, polysaccharides. This is one of the rare reports on ants able to digest plant polysaccharides other than starch.

  2. Training new community health, food service, and environmental protection workers could boost health, jobs, and growth.

    PubMed

    Freudenberg, Nicholas; Tsui, Emma

    2011-11-01

    General job training programs, and separate disease prevention or health promotion programs, are usually viewed as two different strategies for reducing poverty and promoting community development. We propose that with better alignment of the strategies, new jobs with the potential to simultaneously improve population health, lower the cost of health care, and reduce unemployment could be created and filled. Initiatives for three types of entry-level positions-in the fields of community health, environmental remediation and protection, and food preparation-show particular promise as vehicles for health and economic improvement at the individual and community levels. Building on current federal programs, new pilot projects financed by federal funding should be created to test and refine such initiatives and their impact and assemble an evidence base for future policy action.

  3. Differential Recruitment of Camponotus femoratus (Fabricius) Ants in Response to Ant Garden Herbivory.

    PubMed

    Vicente, R E; Dáttilo, W; Izzo, T J

    2014-12-01

    Although several studies have shown that ants can recognize chemical cues from their host plants in ant-plant systems, it is poorly demonstrated in ant gardens (AGs). In this interaction, ant species constantly interact with various epiphyte species. Therefore, it is possible to expect a convergence of chemical signals released by plants that could be acting to ensure that ants are able to recognize and defend epiphyte species frequently associated with AGs. In this study, it was hypothesized that ants recognize and differentiate among chemical stimuli released by AG epiphytes and non-AG epiphytes. We experimentally simulated leaf herbivore damage on three epiphyte species restricted to AGs and a locally abundant understory herb, Piper hispidum, in order to quantify the number of recruited Camponotus femoratus (Fabricius) defenders. When exposed to the AG epiphytes Peperomia macrostachya and Codonanthe uleana leaves, it was observed that the recruitment of C. femoratus workers was, on average, respectively 556% and 246% higher than control. However, the number of ants recruited by the AG epiphyte Markea longiflora or by the non-AG plant did not differ from paper pieces. This indicated that ants could discern between chemicals released by different plants, suggesting that ants can select better plants. These results can be explained by evolutionary process acting on both ants' capability in discerning plants' chemical compounds (innate attraction) or by ants' learning based on the epiphyte frequency in AGs (individual experience). To disentangle an innate behavior, a product of classical coevolutionary process, from an ant's learned behavior, is a complicated but important subject to understand in the evolution of ant-plant mutualisms.

  4. Thermal constraints on foraging of tropical canopy ants.

    PubMed

    Spicer, Michelle Elise; Stark, Alyssa Y; Adams, Benjamin J; Kneale, Riley; Kaspari, Michael; Yanoviak, Stephen P

    2017-04-01

    Small cursorial ectotherms risk overheating when foraging in the tropical forest canopy, where the surfaces of unshaded tree branches commonly exceed 50 °C. We quantified the heating and subsequent cooling rates of 11 common canopy ant species from Panama and tested the hypothesis that ant workers stop foraging at temperatures consistent with the prevention of overheating. We created hot experimental "sunflecks" on existing foraging trails of four ant species from different clades and spanning a broad range of body size, heating rate, and critical thermal maxima (CTmax). Different ant species exhibited very different heating rates in the lab, and these differences did not follow trends predicted by body size alone. Experiments with ant models showed that heating rates are strongly affected by color in addition to body size. Foraging workers of all species showed strong responses to heating and consistently abandoned focal sites between 36 and 44 °C. Atta colombica and Azteca trigona workers resumed foraging shortly after heat was removed, but Cephalotes atratus and Dolichoderus bispinosus workers continued to avoid the heated patch even after >5 min of cooling. Large foraging ants (C. atratus) responded slowly to developing thermal extremes, whereas small ants (A. trigona) evacuated sunflecks relatively quickly, and at lower estimated body temperatures than when revisiting previously heated patches. The results of this study provide the first field-based insight into how foraging ants respond behaviorally to the heterogeneous thermal landscape of the tropical forest canopy.

  5. Alarm Pheromones of the Ant Atta Texana

    Treesearch

    John C. Moser; R. C. Brownlee; R. Silverstein

    1968-01-01

    Methyl-3-heptanone (0.59 μg/head) and 2-heptanone (0.14 μg/head) are the main volatile components of the mandibular glands of major workers. In the laboratory, worker ants detected and were attracted by 4-methyl-3-heptanone at a concentration of 5.7 x 10-13 g/cm3 (2.7 x 107 molecules...

  6. 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).

  7. Red legs and golden gasters: Batesian mimicry in Australian ants.

    PubMed

    Merrill, D N; Elgar, M A

    2000-05-01

    There are numerous reports of invertebrates that are visual mimics of ants, but no formal reports of mimicry of an ant, by an ant. Two endemic Australian ants, Myrmecia fulvipes and Camponotus bendigensis are remarkably similar in colour and size; both are generally black but have red legs and golden gasters. The density and hue of the pubescence of each ant's gaster are relatively uncommon in ants, but are very rare when combined with the black forebody and red legs. The ants are similarly sized but are smaller than other species closely related to M. fulvipes. The range of C. bendigensis lies entirely within that of M. fulvipes, and both species excavate ground nests in open woodland. Finally, workers of both species are crepuscular and forage solitarily. These data suggest that the relatively benign formicine C. bendigensis is a Batesian mimic of the formidable myrmeciine M. fulvipes.

  8. Red legs and golden gasters: Batesian mimicry in australian ants

    NASA Astrophysics Data System (ADS)

    Merrill, D. N.; Elgar, Mark A.

    There are numerous reports of invertebrates that are visual mimics of ants, but no formal reports of mimicry of an ant, by an ant. Two endemic Australian ants, Myrmecia fulvipes and Camponotus bendigensis are remarkably similar in colour and size; both are generally black but have red legs and golden gasters. The density and hue of the pubescence of each ant's gaster are relatively uncommon in ants, but are very rare when combined with the black forebody and red legs. The ants are similarly sized but are smaller than other species closely related to M. fulvipes. The range of C. bendigensis lies entirely within that of M. fulvipes, and both species excavate ground nests in open woodland. Finally, workers of both species are crepuscular and forage solitarily. These data suggest that the relatively benign formicine C. bendigensis is a Batesian mimic of the formidable myrmeciine M. fulvipes.

  9. Do leaf cutting ants cut undetected? Testing the effect of ant-induced plant defences on foraging decisions in Atta colombica.

    PubMed

    Kost, Christian; Tremmel, Martin; Wirth, Rainer

    2011-01-01

    Leaf-cutting ants (LCAs) are polyphagous, yet highly selective herbivores. The factors that govern their selection of food plants, however, remain poorly understood. We hypothesized that the induction of anti-herbivore defences by attacked food plants, which are toxic to either ants or their mutualistic fungus, should significantly affect the ants' foraging behaviour. To test this "induced defence hypothesis," we used lima bean (Phaseolus lunatus), a plant that emits many volatile organic compounds (VOCs) upon herbivore attack with known anti-fungal or ant-repellent effects. Our results provide three important insights into the foraging ecology of LCAs. First, leaf-cutting by Atta ants can induce plant defences: Lima bean plants that were repeatedly exposed to foraging workers of Atta colombica over a period of three days emitted significantly more VOCs than undamaged control plants. Second, the level to which a plant has induced its anti-herbivore defences can affect the LCAs' foraging behaviour: In dual choice bioassays, foragers discriminated control plants from plants that have been damaged mechanically or by LCAs 24 h ago. In contrast, strong induction levels of plants after treatment with the plant hormone jasmonic acid or three days of LCA feeding strongly repelled LCA foragers relative to undamaged control plants. Third, the LCA-specific mode of damaging leaves allows them to remove larger quantities of leaf material before being recognized by the plant: While leaf loss of approximately 15% due to a chewing herbivore (coccinelid beetle) was sufficient to significantly increase VOC emission levels after 24 h, the removal of even 20% of a plant's leaf area within 20 min by LCAs did not affect its VOC emission rate after 24 h. Taken together, our results support the "induced defence hypothesis" and provide first empirical evidence that the foraging behaviour of LCAs is affected by the induction of plant defence responses.

  10. Do Leaf Cutting Ants Cut Undetected? Testing the Effect of Ant-Induced Plant Defences on Foraging Decisions in Atta colombica

    PubMed Central

    Kost, Christian; Tremmel, Martin; Wirth, Rainer

    2011-01-01

    Leaf-cutting ants (LCAs) are polyphagous, yet highly selective herbivores. The factors that govern their selection of food plants, however, remain poorly understood. We hypothesized that the induction of anti-herbivore defences by attacked food plants, which are toxic to either ants or their mutualistic fungus, should significantly affect the ants' foraging behaviour. To test this “induced defence hypothesis,” we used lima bean (Phaseolus lunatus), a plant that emits many volatile organic compounds (VOCs) upon herbivore attack with known anti-fungal or ant-repellent effects. Our results provide three important insights into the foraging ecology of LCAs. First, leaf-cutting by Atta ants can induce plant defences: Lima bean plants that were repeatedly exposed to foraging workers of Atta colombica over a period of three days emitted significantly more VOCs than undamaged control plants. Second, the level to which a plant has induced its anti-herbivore defences can affect the LCAs' foraging behaviour: In dual choice bioassays, foragers discriminated control plants from plants that have been damaged mechanically or by LCAs 24 h ago. In contrast, strong induction levels of plants after treatment with the plant hormone jasmonic acid or three days of LCA feeding strongly repelled LCA foragers relative to undamaged control plants. Third, the LCA-specific mode of damaging leaves allows them to remove larger quantities of leaf material before being recognized by the plant: While leaf loss of approximately 15% due to a chewing herbivore (coccinelid beetle) was sufficient to significantly increase VOC emission levels after 24 h, the removal of even 20% of a plant's leaf area within 20 min by LCAs did not affect its VOC emission rate after 24 h. Taken together, our results support the “induced defence hypothesis” and provide first empirical evidence that the foraging behaviour of LCAs is affected by the induction of plant defence responses. PMID:21799831

  11. Impacts of residual insecticide barriers on perimeter-invading ants, with particular reference to the odorous house ant, Tapinoma sessile.

    PubMed

    Scharf, Michael E; Ratliff, Catina R; Bennett, Gary W

    2004-04-01

    Three liquid insecticide formulations were evaluated as barrier treatments against perimeter-invading ants at a multifamily housing complex in West Lafayette, IN. Several ant species were present at the study site, including (in order of abundance) pavement ant, Tetramorium caespitum (L.); honey ant, Prenolepis imparis (Say); odorous house ant, Tapinoma sessile (Say); thief ant, Solenopsis molesta (Say); acrobat ant, Crematogaster ashmeadi (Mayr); crazy ant, Paratrechina longicornis (Latrielle), field ants, Formica spp.; and carpenter ant Camponotus pennsylvanicus (DeGeer). Studies began in May 2001 and concluded 8 wk later in July. Individual replicate treatments were placed 0.61 in (2 feet) up and 0.92 m (3 feet) out from the ends of 46.1 by 10.1-m (151 by 33-foot) apartment buildings. Ant sampling was performed with 10 placements of moist cat food for 1 h within treatment zones, followed by capture and removal of recruited ants for later counting. All treatments led to substantial reductions in ant numbers relative to untreated controls. The most effective treatment was fipronil, where 2% of before-treatment ant numbers were present at 8 wk after treatment. Both imidacloprid and cyfluthrin barrier treatments had efficacy comparative with fipronil, but to 4 and 2 wk, respectively. Odorous house ants were not sampled before treatment. Comparisons of ant species composition between treatments and controls revealed an increase in odorous house ant frequencies at 1-8 wk after treatment in treated locations only. These results demonstrate efficacy for both nonrepellent and repellent liquid insecticides as perimeter treatments for pest ants. In addition, our findings with odorous house ant highlight an apparent invasive-like characteristic of this species that may contribute to its dramatic increase in structural infestation rates in many areas of the United States.

  12. Monoculture of Leafcutter Ant Gardens

    PubMed Central

    Mueller, Ulrich G.; Scott, Jarrod J.; Ishak, Heather D.; Cooper, Michael; Rodrigues, Andre

    2010-01-01

    Background Leafcutter ants depend on the cultivation of symbiotic Attamyces fungi for food, which are thought to be grown by the ants in single-strain, clonal monoculture throughout the hundreds to thousands of gardens within a leafcutter nest. Monoculture eliminates cultivar-cultivar competition that would select for competitive fungal traits that are detrimental to the ants, whereas polyculture of several fungi could increase nutritional diversity and disease resistance of genetically variable gardens. Methodology/Principal Findings Using three experimental approaches, we assessed cultivar diversity within nests of Atta leafcutter ants, which are most likely among all fungus-growing ants to cultivate distinct cultivar genotypes per nest because of the nests' enormous sizes (up to 5000 gardens) and extended lifespans (10–20 years). In Atta texana and in A. cephalotes, we resampled nests over a 5-year period to test for persistence of resident cultivar genotypes within each nest, and we tested for genetic differences between fungi from different nest sectors accessed through excavation. In A. texana, we also determined the number of Attamyces cells carried as a starter inoculum by a dispersing queens (minimally several thousand Attamyces cells), and we tested for genetic differences between Attamyces carried by sister queens dispersing from the same nest. Except for mutational variation arising during clonal Attamyces propagation, DNA fingerprinting revealed no evidence for fungal polyculture and no genotype turnover during the 5-year surveys. Conclusions/Significance Atta leafcutter ants can achieve stable, fungal monoculture over many years. Mutational variation emerging within an Attamyces monoculture could provide genetic diversity for symbiont choice (gardening biases of the ants favoring specific mutational variants), an analog of artificial selection. PMID:20844760

  13. Patterns and dynamics of neutral lipid fatty acids in ants - implications for ecological studies.

    PubMed

    Rosumek, Félix B; Brückner, Adrian; Blüthgen, Nico; Menzel, Florian; Heethoff, Michael

    2017-01-01

    Trophic interactions are a fundamental aspect of ecosystem functioning, but often difficult to observe directly. Several indirect techniques, such as fatty acid analysis, were developed to assess these interactions. Fatty acid profiles may indicate dietary differences, while individual fatty acids can be used as biomarkers. Ants are among the most important terrestrial animal groups, but little is known about their lipid metabolism, and no study so far used fatty acids to study their trophic ecology. We set up a feeding experiment with high- and low-fat food to elucidate patterns and dynamics of neutral lipid fatty acids (NLFAs) assimilation in ants. We asked whether dietary fatty acids are assimilated through direct trophic transfer, how diet influences NLFA total amounts and patterns over time, and whether these assimilation processes are similar across species and life stages. Ants fed with high-fat food quickly accumulated specific dietary fatty acids (C18:2n6, C18:3n3 and C18:3n6), compared to ants fed with low-fat food. Dietary fat content did not affect total body fat of workers or amounts of fatty acids extensively biosynthesized by animals (C16:0, C18:0, C18:1n9). Larval development had a strong effect on the composition and amounts of C16:0, C18:0 and C18:1n9. NLFA compositions reflected dietary differences, which became more pronounced over time. Assimilation of specific dietary NLFAs was similar regardless of species or life stage, but these factors affected dynamics of other NLFAs, composition and total fat. We showed that ants accumulated certain dietary fatty acids via direct trophic transfer. Fat content of the diet had no effect on lipids stored by ants, which were able to synthesize high amounts of NLFAs from a sugar-based diet. Nevertheless, dietary NLFAs had a strong effect on metabolic dynamics and profiles. Fatty acids are a useful tool to study trophic biology of ants, and could be applied in an ecological context, although factors that

  14. A World of Ants.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1992-01-01

    Presents a discussion of interesting aspects of ants that was launched by the author's reading of "The Ants" by Holldobler and Wilson (1990). Describes how the study of the early history of ant taxonomy could be viewed as "entertaining." Their huge numbers and segregation into colonial social systems makes ants good research organisms. (PR)

  15. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

    NASA Astrophysics Data System (ADS)

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  16. Information Needs at the Beginning of Foraging: Grass-Cutting Ants Trade Off Load Size for a Faster Return to the Nest

    PubMed Central

    Bollazzi, Martin; Roces, Flavio

    2011-01-01

    Background Acquisition of information about food sources is essential for animals that forage collectively like social insects. Foragers deliver two commodities to the nest, food and information, and they may favor the delivery of one at the expenses of the other. We predict that information needs should be particularly high at the beginning of foraging: the decision to return faster to the nest will motivate a grass-cutting ant worker to reduce its loading time, and so to leave the source with a partial load. Principal Findings Field results showed that at the initial foraging phase, most grass-cutting ant foragers (Acromyrmex heyeri) returned unladen to the nest, and experienced head-on encounters with outgoing workers. Ant encounters were not simply collisions in a probabilistic sense: outgoing workers contacted in average 70% of the returning foragers at the initial foraging phase, and only 20% at the established phase. At the initial foraging phase, workers cut fragments that were shorter, narrower, lighter and tenderer than those harvested at the established one. Foragers walked at the initial phase significantly faster than expected for the observed temperatures, yet not at the established phase. Moreover, when controlling for differences in the fragment-size carried, workers still walked faster at the initial phase. Despite the higher speed, their individual transport rate of vegetable tissue was lower than that of similarly-sized workers foraging later at the same patch. Conclusions/Significance At the initial foraging phase, workers compromised their individual transport rates of material in order to return faster to the colony. We suggest that the observed flexible cutting rules and the selection of partial loads at the beginning of foraging are driven by the need of information transfer, crucial for the establishment and maintenance of a foraging process to monopolize a discovered resource. PMID:21408014

  17. Information needs at the beginning of foraging: grass-cutting ants trade off load size for a faster return to the nest.

    PubMed

    Bollazzi, Martin; Roces, Flavio

    2011-03-09

    Acquisition of information about food sources is essential for animals that forage collectively like social insects. Foragers deliver two commodities to the nest, food and information, and they may favor the delivery of one at the expenses of the other. We predict that information needs should be particularly high at the beginning of foraging: the decision to return faster to the nest will motivate a grass-cutting ant worker to reduce its loading time, and so to leave the source with a partial load. Field results showed that at the initial foraging phase, most grass-cutting ant foragers (Acromyrmex heyeri) returned unladen to the nest, and experienced head-on encounters with outgoing workers. Ant encounters were not simply collisions in a probabilistic sense: outgoing workers contacted in average 70% of the returning foragers at the initial foraging phase, and only 20% at the established phase. At the initial foraging phase, workers cut fragments that were shorter, narrower, lighter and tenderer than those harvested at the established one. Foragers walked at the initial phase significantly faster than expected for the observed temperatures, yet not at the established phase. Moreover, when controlling for differences in the fragment-size carried, workers still walked faster at the initial phase. Despite the higher speed, their individual transport rate of vegetable tissue was lower than that of similarly-sized workers foraging later at the same patch. At the initial foraging phase, workers compromised their individual transport rates of material in order to return faster to the colony. We suggest that the observed flexible cutting rules and the selection of partial loads at the beginning of foraging are driven by the need of information transfer, crucial for the establishment and maintenance of a foraging process to monopolize a discovered resource.

  18. Advances in Research on the Venom Chemistry of Imported Fire Ants

    USDA-ARS?s Scientific Manuscript database

    Workers of the imported fire ants, including red imported fire ants, Solenopsis invicta Buren, black imported fire ants, S. richteri Forel, and their hybrid (S. invicta × S. richteri), are vicious stingers. Since the venomous sting is a significant medical problem to humans, the chemistry of import...

  19. Abundance of -1,6-piperideine alkaloids in imported fire ants

    USDA-ARS?s Scientific Manuscript database

    Workers of imported fire ants, including red imported fire ants, Solenopsis invicta Buren, black imported fire ants, S. richteri Forel, and their hybrid (S. invicta × S. richteri), are vicious stingers. Since the venomous sting is a significant medical problem to humans, the chemistry of imported f...

  20. Plasticity of Daily Behavioral Rhythms in Foragers and Nurses of the Ant Camponotus rufipes: Influence of Social Context and Feeding Times

    PubMed Central

    Mildner, Stephanie; Roces, Flavio

    2017-01-01

    Daily activities within an ant colony need precise temporal organization, and an endogenous clock appears to be essential for such timing processes. A clock drives locomotor rhythms in isolated workers in a number of ant species, but its involvement in activities displayed in the social context is unknown. We compared locomotor rhythms in isolated individuals and behavioral rhythms in the social context of workers of the ant Camponotus rufipes. Both forager and nurse workers exhibited circadian rhythms in locomotor activity under constant conditions, indicating the involvement of an endogenous clock. Activity was mostly nocturnal and synchronized with the 12:12h light-dark-cycle. To evaluate whether rhythmicity was maintained in the social context and could be synchronized with non-photic zeitgebers such as feeding times, daily behavioral activities of single workers inside and outside the nest were quantified continuously over 24 hours in 1656 hours of video recordings. Food availability was limited to a short time window either at day or at night, thus mimicking natural conditions of temporally restricted food access. Most foragers showed circadian foraging behavior synchronized with food availability, either at day or nighttime. When isolated thereafter in single locomotor activity monitors, foragers mainly displayed arrhythmicity. Here, high mortality suggested potential stressful effects of the former restriction of food availability. In contrast, nurse workers showed high overall activity levels in the social context and performed their tasks all around the clock with no circadian pattern, likely to meet the needs of the brood. In isolation, the same individuals exhibited in turn strong rhythmic activity and nocturnality. Thus, endogenous activity rhythms were inhibited in the social context, and timing of daily behaviors was flexibly adapted to cope with task demands. As a similar socially-mediated plasticity in circadian rhythms was already shown in honey

  1. Fermat’s Principle of Least Time Predicts Refraction of Ant Trails at Substrate Borders

    PubMed Central

    Zankl, Niko; Rey, Olivier; Dress, Andreas; Heinze, Jürgen

    2013-01-01

    Fermat’s principle of least time states that light rays passing through different media follow the fastest (and not the most direct) path between two points, leading to refraction at medium borders. Humans intuitively employ this rule, e.g., when a lifeguard has to infer the fastest way to traverse both beach and water to reach a swimmer in need. Here, we tested whether foraging ants also follow Fermat’s principle when forced to travel on two surfaces that differentially affected the ants’ walking speed. Workers of the little fire ant, Wasmannia auropunctata, established “refracted” pheromone trails to a food source. These trails deviated from the most direct path, but were not different to paths predicted by Fermat’s principle. Our results demonstrate a new aspect of decentralized optimization and underline the versatility of the simple yet robust rules governing the self-organization of group-living animals. PMID:23527263

  2. Variation in Extrafloral Nectary Productivity Influences the Ant Foraging

    PubMed Central

    2017-01-01

    Extrafloral nectar is the main food source offered by plants to predatory ants in most land environments. Although many studies have demonstrated the importance of extrafloral nectaries (EFNs) to plant defense against herbivores, the influence of EFNs secretory activity pattern on predatory ants remains yet not fully understood. Here, we verified the relation between the extrafloral nectar production of a plant community in Cerrado in different times of the day, and its attractiveness to ants. The extrafloral nectaries (EFNs) of seven plant species showed higher productivity overnight. Ant abundance was higher in times of large extrafloral nectar production, however, there was no positive relation between ant richness on plants and EFNs productivity. There was temporal resource partitioning among ant species, and it indicates strong resource competition. The nectar productivity varied among plant species and time of the day, and it influenced the visitation patterns of ants. Therefore, EFNs are a key ant-plant interaction driver in the studied system. PMID:28046069

  3. Variation in Extrafloral Nectary Productivity Influences the Ant Foraging.

    PubMed

    Lange, Denise; Calixto, Eduardo Soares; Del-Claro, Kleber

    2017-01-01

    Extrafloral nectar is the main food source offered by plants to predatory ants in most land environments. Although many studies have demonstrated the importance of extrafloral nectaries (EFNs) to plant defense against herbivores, the influence of EFNs secretory activity pattern on predatory ants remains yet not fully understood. Here, we verified the relation between the extrafloral nectar production of a plant community in Cerrado in different times of the day, and its attractiveness to ants. The extrafloral nectaries (EFNs) of seven plant species showed higher productivity overnight. Ant abundance was higher in times of large extrafloral nectar production, however, there was no positive relation between ant richness on plants and EFNs productivity. There was temporal resource partitioning among ant species, and it indicates strong resource competition. The nectar productivity varied among plant species and time of the day, and it influenced the visitation patterns of ants. Therefore, EFNs are a key ant-plant interaction driver in the studied system.

  4. The capacity of a Myrmica ant nest to support a predacious species of Maculinea butterfly.

    PubMed

    Thomas, J A; Wardlaw, J C

    1992-08-01

    Caterpillars of Maculinea arion are obligate predators of the brood of Myrmica sabuleti ants. In the aboratory, caterpillars eat the largest available ant larvae, although eggs, small larvae and prepupae are also palatable. This is an efficient way to predate. It ensures that newly-adopted caterpillars consume the final part of the first cohort of ant brood in a nest, before this pupates in early autumn and becomes unavailable as prey. At the same time, the fixed number of larvae in the second cohort is left to grow larger before being killed in late autumn and spring. Caterpillars also improve their feeding efficiency by hibernating for longer than ants in spring, losing just 6% of their weight while the biomass of ant larvae increases by 27%. Final instar caterpillars acquire more than 99% of their ultimate biomass in Myrmica nests, growing from 1.3 mg to an estimated 173 mg. A close correlation was found between the weights of caterpillars throughout autumn and the number of large ant larvae they had eaten. This was used to calculate the number of larvae eaten in spring, allowing both for the loss of caterpillar weight during winter and the increase in the size of their prey in spring. It is estimated that 230 of the largest available larvae, and a minimum nest size of 354 M. sabuleti workers, is needed to support one butterfly. Few wild M. sabuleti nests are this large: on one site, it was estimated that 85% of nests were too small to produce a butterfly, and only 5% could support two or more. This prediction was confirmed by the mortalities of 376 caterpillars in 151 wild M. sabuleti nests there. Mortalities were particularly high in nests that adopted more than two caterpillars, apparently due to scramble competition and starvation in autumn. Survival was higher than predicted in wild nests that adopted one caterpillar. These caterpillars seldom exhaust their food before spring, when there is intense competition among Myrmica for nest sites. Ants often desert

  5. [The ants: a strategy of population concentration].

    PubMed

    Zakharov, A A

    2011-01-01

    Ants are provided with a balanced system of reactions either to the original paucity of socia or to their secondary depopulation. This system can be defined as a strategy of population concentration. Both a successful reproduction of workers and queen fertilization are necessary conditions for ant communities' survival and development. Thus, the anthills must be large enough to ensure optimal conditions for reproduction. It is the strategy of population concentration that is directed to an accelerated attainment (or rehabilitation) by a socium of a state of stable development by way of concentrating the existent ant staff in an accessible number of viable nests. This strategy is realized throughout the life of ant communities by way of (a) fusing the starting family cells left by founder females, (b) fusing small anthills during artificial ant migrations, (c) uniting smaller socia or their joining other anthills, (d) reintegrating the secondary anthills (fragmentants) after an exogenous fragmentation of formicaries. Pooling and the attraction of deficient demographic resources from outside form the most efficient and quickest ways of reaching or restoring the threshold density levels. By realizing this strategy, the ants solve their paramount problems of anthill or settlement conservation at any particular time, as well as of providing some prospects for ant existence in the future. These problems are so vital for ant socia that they appear to hold priority over such other characteristics of utmost importance as genetic kinship or even species identity. The priority of social basics over genetic ones is unequivocally supported through mixed formicaries. A necessary condition for the realization of the strategy of population concentration is tolerance of highly developed social systems to the diversity of forms and to deviations from the norm. The use of one and the same mechanism at all stages of the life both of an individual socium and large ant settlements is

  6. Pseudacteon decapitating fly parasitism rates in fire ant colonies around Gainesville, Florida

    USDA-ARS?s Scientific Manuscript database

    In order to assess the impacts of phorid flies on fire ants in the Gainesville area, we collected 3 g of worker ants from 36 colonies. A total of 672 parasitized workers were recovered from the 36 colony samples. Confirmed parasitism rates ranged from 0-5% with an average of about 0.5%. Including c...

  7. Uncovering the complexity of ant foraging trails.

    PubMed

    Czaczkes, Tomer J; Grüter, Christoph; Jones, Sam M; Ratnieks, Francis L W

    2012-01-01

    The common garden ant Lasius niger use both trail pheromones and memory of past visits to navigate to and from food sources. In a recent paper we demonstrated a synergistic effect between route memory and trail pheromones: the presence of trail pheromones results in experienced ants walking straighter and faster. We also found that experienced ants leaving a pheromone trail deposit less pheromone. Here we focus on another finding of the experiment: the presence of cuticular hydrocarbons (CHCs), which are used as home range markers by ants, also affects pheromone deposition behavior. When walking on a trail on which CHCs are present but trail pheromones are not, experienced foragers deposit less pheromone on the outward journey than on the return journey. The regulatory mechanisms ants use during foraging and recruitment behavior is subtle and complex, affected by multiple interacting factors such as route memory, travel direction and the presence trail pheromone and home-range markings.

  8. Nest architecture shapes the collective behaviour of harvester ants

    PubMed Central

    Pinter-Wollman, Noa

    2015-01-01

    Structures influence how individuals interact and, therefore, shape the collective behaviours that emerge from these interactions. Here I show that the structure of a nest influences the collective behaviour of harvester ant colonies. Using network analysis, I quantify nest architecture and find that as chamber connectivity and redundancy of connections among chambers increase, so does a colony's speed of recruitment to food. Interestingly, the volume of the chambers did not influence speed of recruitment, suggesting that the spatial organization of a nest has a greater impact on collective behaviour than the number of workers it can hold. Thus, by changing spatial constraints on social interactions organisms can modify their behaviour and impact their fitness. PMID:26490416

  9. Nest architecture shapes the collective behaviour of harvester ants.

    PubMed

    Pinter-Wollman, Noa

    2015-10-01

    Structures influence how individuals interact and, therefore, shape the collective behaviours that emerge from these interactions. Here I show that the structure of a nest influences the collective behaviour of harvester ant colonies. Using network analysis, I quantify nest architecture and find that as chamber connectivity and redundancy of connections among chambers increase, so does a colony's speed of recruitment to food. Interestingly, the volume of the chambers did not influence speed of recruitment, suggesting that the spatial organization of a nest has a greater impact on collective behaviour than the number of workers it can hold. Thus, by changing spatial constraints on social interactions organisms can modify their behaviour and impact their fitness. © 2015 The Author(s).

  10. How Ants Drop Out: Ant Abundance on Tropical Mountains

    PubMed Central

    Longino, John T.; Branstetter, Michael G.; Colwell, Robert K.

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops. PMID:25098722

  11. Plant defences against ants provide a pathway to social parasitism in butterflies.

    PubMed

    Patricelli, Dario; Barbero, Francesca; Occhipinti, Andrea; Bertea, Cinzia M; Bonelli, Simona; Casacci, Luca P; Zebelo, Simon A; Crocoll, Christoph; Gershenzon, Jonathan; Maffei, Massimo E; Thomas, Jeremy A; Balletto, Emilio

    2015-07-22

    Understanding the chemical cues and gene expressions that mediate herbivore-host-plant and parasite-host interactions can elucidate the ecological costs and benefits accruing to different partners in tight-knit community modules, and may reveal unexpected complexities. We investigated the exploitation of sequential hosts by the phytophagous-predaceous butterfly Maculinea arion, whose larvae initially feed on Origanum vulgare flowerheads before switching to parasitize Myrmica ant colonies for their main period of growth. Gravid female butterflies were attracted to Origanum plants that emitted high levels of the monoterpenoid volatile carvacrol, a condition that occurred when ants disturbed their roots: we also found that Origanum expressed four genes involved in monoterpene formation when ants were present, accompanied by a significant induction of jasmonates. When exposed to carvacrol, Myrmica workers upregulated five genes whose products bind and detoxify this biocide, and their colonies were more tolerant of it than other common ant genera, consistent with an observed ability to occupy the competitor-free spaces surrounding Origanum. A cost is potential colony destruction by Ma. arion, which in turn may benefit infested Origanum plants by relieving their roots of further damage. Our results suggest a new pathway, whereby social parasites can detect successive resources by employing plant volatiles to simultaneously select their initial plant food and a suitable sequential host.

  12. Plant defences against ants provide a pathway to social parasitism in butterflies

    PubMed Central

    Patricelli, Dario; Barbero, Francesca; Occhipinti, Andrea; Bertea, Cinzia M.; Bonelli, Simona; Casacci, Luca P.; Zebelo, Simon A.; Crocoll, Christoph; Gershenzon, Jonathan; Maffei, Massimo E.; Thomas, Jeremy A.; Balletto, Emilio

    2015-01-01

    Understanding the chemical cues and gene expressions that mediate herbivore–host-plant and parasite–host interactions can elucidate the ecological costs and benefits accruing to different partners in tight-knit community modules, and may reveal unexpected complexities. We investigated the exploitation of sequential hosts by the phytophagous–predaceous butterfly Maculinea arion, whose larvae initially feed on Origanum vulgare flowerheads before switching to parasitize Myrmica ant colonies for their main period of growth. Gravid female butterflies were attracted to Origanum plants that emitted high levels of the monoterpenoid volatile carvacrol, a condition that occurred when ants disturbed their roots: we also found that Origanum expressed four genes involved in monoterpene formation when ants were present, accompanied by a significant induction of jasmonates. When exposed to carvacrol, Myrmica workers upregulated five genes whose products bind and detoxify this biocide, and their colonies were more tolerant of it than other common ant genera, consistent with an observed ability to occupy the competitor-free spaces surrounding Origanum. A cost is potential colony destruction by Ma. arion, which in turn may benefit infested Origanum plants by relieving their roots of further damage. Our results suggest a new pathway, whereby social parasites can detect successive resources by employing plant volatiles to simultaneously select their initial plant food and a suitable sequential host. PMID:26156773

  13. Who needs ‘lazy’ workers? Inactive workers act as a ‘reserve’ labor force replacing active workers, but inactive workers are not replaced when they are removed

    PubMed Central

    Sasaki, Takao; Dornhaus, Anna

    2017-01-01

    Social insect colonies are highly successful, self-organized complex systems. Surprisingly however, most social insect colonies contain large numbers of highly inactive workers. Although this may seem inefficient, it may be that inactive workers actually contribute to colony function. Indeed, the most commonly proposed explanation for inactive workers is that they form a ‘reserve’ labor force that becomes active when needed, thus helping mitigate the effects of colony workload fluctuations or worker loss. Thus, it may be that inactive workers facilitate colony flexibility and resilience. However, this idea has not been empirically confirmed. Here we test whether colonies of Temnothorax rugatulus ants replace highly active (spending large proportions of time on specific tasks) or highly inactive (spending large proportions of time completely immobile) workers when they are experimentally removed. We show that colonies maintained pre-removal activity levels even after active workers were removed, and that previously inactive workers became active subsequent to the removal of active workers. Conversely, when inactive workers were removed, inactivity levels decreased and remained lower post-removal. Thus, colonies seem to have mechanisms for maintaining a certain number of active workers, but not a set number of inactive workers. The rapid replacement (within 1 week) of active workers suggests that the tasks they perform, mainly foraging and brood care, are necessary for colony function on short timescales. Conversely, the lack of replacement of inactive workers even 2 weeks after their removal suggests that any potential functions they have, including being a ‘reserve’, are less important, or auxiliary, and do not need immediate recovery. Thus, inactive workers act as a reserve labor force and may still play a role as food stores for the colony, but a role in facilitating colony-wide communication is unlikely. Our results are consistent with the often cited

  14. Ant foraging on complex trails: route learning and the role of trail pheromones in Lasius niger.

    PubMed

    Czaczkes, Tomer J; Grüter, Christoph; Ellis, Laura; Wood, Elizabeth; Ratnieks, Francis L W

    2013-01-15

    Ants are central place foragers and use multiple information sources to navigate between the nest and feeding sites. Individual ants rapidly learn a route, and often prioritize memory over pheromone trails when tested on a simple trail with a single bifurcation. However, in nature, ants often forage at locations that are reached via more complex routes with multiple trail bifurcations. Such routes may be more difficult to learn, and thus ants would benefit from additional information. We hypothesized that trail pheromones play a more significant role in ant foraging on complex routes, either by assisting in navigation or route learning or both. We studied Lasius niger workers foraging on a doubly bifurcating trail with four end points. Route learning was slower and errors greater on alternating (e.g. left-right) versus repeating routes (e.g. left-left), with error rates of 32 and 3%, respectively. However, errors on alternating routes decreased by 30% when trail pheromone was present. Trail pheromones also aid route learning, leading to reduced errors in subsequent journeys without pheromone. If an experienced forager makes an error when returning to a food source, it reacts by increasing pheromone deposition on the return journey. In addition, high levels of trail pheromone suppress further pheromone deposition. This negative feedback mechanism may act to conserve pheromone or to regulate recruitment. Taken together, these results demonstrate further complexity and sophistication in the foraging system of ant colonies, especially in the role of trail pheromones and their relationship with learning and the use of private information (memory) in a complex environment.

  15. Impact of ecological doses of the most widespread phthalate on a terrestrial species, the ant Lasius niger.

    PubMed

    Cuvillier-Hot, Virginie; Salin, Karine; Devers, Séverine; Tasiemski, Aurélie; Schaffner, Pauline; Boulay, Raphaël; Billiard, Sylvain; Lenoir, Alain

    2014-05-01

    Phthalates are synthetic contaminants released into the environment notably by plastic waste. Semi-volatile, they adsorb to atmospheric particles and get distributed in all ecosystems. Effects of this major anthropogenic pollution in economical species in aquatic habitats have attracted large interest. On the contrary, very few studies have focused on wild terrestrial species. Yet, these lipophilic molecules are easily trapped by insect cuticle; ants and other insects have been shown to permanently bear among their cuticular components a non-negligible proportion of phthalates, meaning that they suffer from chronic exposure to these pollutants. Oral route could also be an additional way of contamination, as phthalates tend to stick to any organic particle. We show here via a food choice experiment that Lasius niger workers can detect, and avoid feeding on, food contaminated with DEHP (DiEthyl Hexyl Phthalate), the most widespread phthalate found in nature. This suggests that the main source of contamination for ants is atmosphere and that doses measured on the cuticle correspond to the chronic exposure levels for these animals. Such an ecologically relevant dose of DEHP was used to contaminate ants in lab and to investigate their physiological impact. Over a chronic exposure (1 dose per week for 5 weeks), the egg-laying rate of queens was significantly reduced lending credence to endocrine disruptive properties of such a pollutant, as also described for aquatic invertebrates. On the contrary, short term exposure (24h) to a single dose of DEHP does not induce oxidative stress in ant workers as expected, but leads to activation of the immune system. Because of their very large distribution, their presence in virtually all terrestrial ecosystems and their representation at all trophic levels, ants could be useful indicators of contamination by phthalates, especially via monitoring the level of activation of their immune state. Copyright © 2014 Elsevier Inc. All

  16. Coexistence between Cyphomyrmex ants and dominant populations of Wasmannia auropunctata.

    PubMed

    Grangier, Julien; Le Breton, Julien; Dejean, Alain; Orivel, Jérôme

    2007-01-10

    The little fire ant Wasmannia auropunctata is able to develop highly dominant populations in disturbed areas of its native range, with a resulting negative impact on ant diversity. We report here on the tolerance of such populations towards several fungus-growing ants of the genus Cyphomyrmex (rimosus complex) in French Guiana. This tolerance is surprising given the usually high interspecific aggressiveness of W. auropunctata when dominant. In order to understand the mechanisms behind such proximity, aggressiveness tests were performed between workers of the different species. These behavioural assays revealed a great passivity in Cyphomyrmex workers during confrontations with W. auropunctata workers. We also found that the aggressiveness between W. auropunctata and two Cyphomyrmex species was more intense between distant nests than between adjacent ones. This dear-enemy phenomenon may result from a process of habituation contributing to the ants' ability to coexist over the long term.

  17. Chemical signals associated with life inhibit necrophoresis in Argentine ants

    PubMed Central

    Choe, Dong-Hwan; Millar, Jocelyn G.; Rust, Michael K.

    2009-01-01

    One of the most conspicuous and stereotyped activities of social insects such as ants and honey bees is necrophoresis, the removal of dead colony members from the nest. Previous researchers suggested that decomposition products such as fatty acids trigger necrophoric behavior by ant workers. However, fatty acids elicit both foraging and necrophoric responses, depending on the current nest activities (e.g., feeding or nest maintenance). Furthermore, workers often carry even freshly killed workers (dead for <1 h) to refuse piles before significant decomposition has a chance to occur. Here, we show that the cuticular chemistry of Argentine ant workers, Linepithema humile, undergoes rapid changes after death. When the workers are alive or freshly killed, relatively large amounts of 2 characteristic ant-produced compounds, dolichodial and iridomyrmecin, are present on the ants' cuticle. However, these compounds disappear from the cuticle within about 1 h after death. We demonstrate how this phenomenon supports an alternative mechanism of ant necrophoresis in which the precise recognition and rapid removal of dead nestmates are elicited by the disappearance of these chemical signals associated with life. PMID:19416815

  18. Effects of Food Label Use on Diet Quality and Glycemic Control Among Latinos With Type 2 Diabetes in a Community Health Worker-Supported Intervention.

    PubMed

    Kollannoor-Samuel, Grace; Shebl, Fatma M; Segura-Pérez, Sofia; Chhabra, Jyoti; Vega-López, Sonia; Pérez-Escamilla, Rafael

    2016-06-01

    To determine the impact of an intervention led by community health workers (CHWs) on food label use and to assess whether food label use and diet quality mediate the intervention's impact on glycemic control. From 2006 to 2010, 203 Latinos (intervention group, n = 100; control group, n = 103) in Hartford County, Connecticut, with type 2 diabetes were randomized to an intervention that included 17 CHW-led home-based sessions over a 12-month period in addition to the standard of care available in both study arms. Data on food label use, diet quality, covariates, and glycated hemoglobin (HbA1c) were collected at baseline and at 3, 6, 12, and 18 months. Data were analyzed via mixed effects and multilevel structural equation modeling. Food label use in the intervention (vs control) group was significantly higher at 3, 12, and 18 months (odds ratio = 2.99; 95% confidence interval = 1.69, 5.29). Food label use and diet quality were positive mediators of improved HbA1c levels. Culturally tailored interventions led by CHWs could increase food label use. Also, CHW-delivered food label education may lead to better diet quality and improve glycemic control among Latinos with type 2 diabetes.

  19. The ant, Aphaenogaster picea, benefits from plant elaiosomes when insect prey is scarce.

    PubMed

    Clark, Robert E; King, Joshua R

    2012-12-01

    Myrmecochory is a facultative, mutualistic interaction in which ants receive a protein-rich food reward (elaiosome) in return for dispersing plant seeds. In North American northeastern hardwood forests, Aphaenogaster ants are the primary genus dispersing myrmecochorous plants. In these forests, myrmecochores occur in plant guilds of understory spring ephemerals or seasonal greens. This mutualism has been demonstrated for Aphaenogaster rudis (Emery) and individual plant species, but it has not been demonstrated for other Aphaenogaster species or guilds of myrmecochores as they naturally occur. Aphaenogaster picea (Wheeler) colonies were fed three treatments over 5 mo: 1) a mixture of only elaiosomes from an entire plant guild, 2) a diet of only insect protein and 3) a combination diet of both elaiosomes and insect protein. This experiment investigated two potential hypotheses through which elaiosomes can benefit ants: 1) elaiosome proteins can substitute for protein nutritional requirements when ants are prey-limited, and 2) elaiosome nutrition can supplement insect protein when prey is ample. First, a mixture of elaiosomes from four myrmecochorous plant species provided to A. picea colonies was sufficient to maintain worker production, larval growth, and fat stores when no other food was available. A. picea colonies consuming elaiosomes as their only protein source could be sustained for a growing season (5 mo). Second, colonies fed both elaiosomes and protein did not yield more productive colonies than a control diet of just insect protein. These results support the hypothesis that myrmecochory is indeed a facultative mutualism in which ants take advantage of the protein content of elaiosomes when it is favorable, but when they are not limited by insect prey they do not gain any additional benefit from elaiosomes.

  20. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 1. Description of the problem, methods, and agents involved.

    PubMed

    Greig, Judy D; Todd, Ewen C D; Bartleson, Charles A; Michaels, Barry S

    2007-07-01

    Food workers in many settings have been responsible for foodborne disease outbreaks for decades, and there is no indication that this is diminishing. The Committee on Control of Foodborne Illnesses of the International Association for Food Protection was tasked with collecting and evaluating any data on worker-associated outbreaks. A total of 816 reports with 80,682 cases were collected from events that occurred from 1927 until the first quarter of 2006. Most of the outbreaks reviewed were from the United States, Canada, Europe, and Australia, with relatively few from other parts of the world, indicating the skewed set of data because of availability in the literature or personal contact. Outbreaks were caused by 14 agents: norovirus or probable norovirus (338), Salmonella enterica (151), hepatitis A virus (84), Staphylococcus aureus (53), Shigella spp. (33), Streptococcus Lancefield groups A and G (17), and parasites Cyclospora, Giardia, and Cryptosporidium (23). Streptococcal, staphylococcal, and typhoid outbreaks seem to be diminishing over time; hepatitis A virus remains static, whereas norovirus and maybe nontyphoidal Salmonella are increasing. Multiple foods and multi-ingredient foods were identified most frequently with outbreaks, perhaps because of more frequent hand contact during preparation and serving.

  1. Fire disturbance disrupts an acacia ant-plant mutualism in favor of a subordinate ant species.

    PubMed

    Sensenig, Ryan L; Kimuyu, Duncan K; Ruiz Guajardo, Juan C; Veblen, Kari E; Riginos, Corinna; Young, Truman P

    2017-05-01

    Although disturbance theory has been recognized as a useful framework in examining the stability of ant-plant mutualisms, very few studies have examined the effects of fire disturbance on these mutualisms. In myrmecophyte-dominated savannas, fire and herbivory are key drivers that could influence ant-plant mutualisms by causing complete colony mortality and/or decreasing colony size, which potentially could alter dominance hierarchies if subordinate species are more fire resilient. We used a large-scale, replicated fire experiment to examine long-term effects of fire on acacia-ant community composition. To determine if fire shifted ant occupancy from a competitive dominant to a subordinate ant species, we surveyed the acacia-ant community in 6-7 yr old burn sites and examined how the spatial scale of these burns influenced ant community responses. We then used two short-term fire experiments to explore possible mechanisms for the shifts in community patterns observed. Because survival of ant colonies is largely dependent on their ability to detect and escape an approaching fire, we first tested the evacuation response of all four ant species when exposed to smoke (fire signal). Then to better understand how fire and its interaction with large mammal herbivory affect the density of ants per tree, we quantified ant worker density in small prescribed burns within herbivore exclusion plots. We found clear evidence suggesting that fire disturbance favored the subordinate ant Crematogaster nigriceps more than the dominant and strong mutualist ant C. mimosae, whereby C. nigriceps (1) was the only species to occupy a greater proportion of trees in 6-7 yr old burn sites compared to unburned sites, (2) had higher burn/unburn tree ratios with increasing burn size, and (3) evacuated significantly faster than C. mimosae in the presence of smoke. Fire and herbivory had opposite effects on ant density per meter of branch for both C. nigriceps and C. mimosae, with fire

  2. Coming of age in an ant colony: cephalic muscle maturation accompanies behavioral development in Pheidole dentata

    NASA Astrophysics Data System (ADS)

    Muscedere, Mario L.; Traniello, James F. A.; Gronenberg, Wulfila

    2011-09-01

    Although several neurobiological and genetic correlates of aging and behavioral development have been identified in social insect workers, little is known about how other age-related physiological processes, such as muscle maturation, contribute to task performance. We examined post-eclosion growth of three major muscles of the head capsule in major and minor workers of the ant Pheidole dentata using workers of different ages with distinct task repertoires. Mandible closer muscle fibers, which provide bite force and are thus critical for the use of the mandibles for biting and load carrying, fill the posterio-lateral portions of the head capsule in mature, older workers of both subcastes. Mandible closer fibers of newly eclosed workers, in contrast, are significantly thinner in both subcastes and grow during at least the next 6 days in minor workers, suggesting this muscle has reduced functionality for a substantial period of adult life and thus constrains task performance capability. Fibers of the antennal muscles and the pharynx dilator, which control antennal movements and food intake, respectively, also increase significantly in thickness with age. However, these fibers are only slightly thinner in newly eclosed workers and attain their maximum thickness over a shorter time span in minors. The different growth rates of these functionally distinct muscles likely have consequences for how adult P. dentata workers, particularly minors, develop their full and diverse task repertoire as they age. Workers may be capable of feeding and interacting socially soon after eclosion, but require a longer period of development to effectively use their mandibles, which enable the efficient performance of tasks ranging from nursing to foraging and defense.

  3. The Effects of Colony Structure and Resource Abundance on Food Dispersal in Tapinoma sessile (Hymenoptera: Formicidae)

    PubMed Central

    VanWeelden, M. T.; Bennett, G.; Buczkowski, G.

    2015-01-01

    The odorous house ant, Tapinoma sessile (Say) (Hymenoptera: Formicidae), exhibits a high degree of variation in colony spatial structure which may have direct and indirect effects on foraging. Protein marking and mark–release–recapture techniques were utilized to examine the effect of colony spatial structure on food dispersal. Sucrose water spiked with rabbit IgG protein was presented to colonies with varying spatial configurations in laboratory and field experiments. In monodomous lab colonies, the rate and extent of food dispersal was rapid due to a decrease in foraging area. In polydomous colonies, food dispersal was slower because conspecifics were forced to forage and share food over longer distances. However, over time, food was present in all extremities of the colony. Experiments conducted in the field produced similar results, with nests in close proximity to food yielding higher percentages of workers scoring positive for the marker. However, the percentage of workers possessing the marker decreased over time. Results from this study provide experimental data on mechanisms of food dispersal in monodomous and polydomous colonies of ants, and may be important for increasing the efficacy of management strategies against T. sessile and other pest ant species. PMID:25688088

  4. Mutualism exploitation: predatory drosophilid larvae sugar-trap ants and jeopardize facultative ant-plant mutualism.

    PubMed

    Vidal, Mayra C; Sendoya, Sebastian F; Oliveira, Paulo S

    2016-07-01

    An open question in the evolutionary ecology of ant-plant facultative mutualism is how other members of the associated community can affect the interaction to a point where reciprocal benefits are disrupted. While visiting Qualea grandiflora shrubs to collect sugary rewards at extrafloral nectaries, tropical savanna ants deter herbivores and reduce leaf damage. Here we show that larvae of the fly Rhinoleucophenga myrmecophaga, which develop on extrafloral nectaries, lure potentially mutualistic, nectar-feeding ants and prey on them. Foraging ants spend less time on fly-infested foliage. Field experiments showed that predation (or the threat of predation) on ants by fly larvae produces cascading effects through three trophic levels, resulting in fewer protective ants on leaves, increased numbers of chewing herbivores, and greater leaf damage. These results reveal an undocumented mode of mutualism exploitation by an opportunistic predator at a plant-provided food source, jeopardizing ant-derived protection services to the plant. Our study documents a rather unusual case of predation of adult ants by a dipteran species and demonstrates a top-down trophic cascade within a generalized ant-plant mutualism. © 2016 by the Ecological Society of America.

  5. An overlooked mandibular-rubbing behavior used during recruitment by the African weaver ant, Oecophylla longinoda.

    PubMed

    Roux, Olivier; Billen, Johan; Orivel, Jérôme; Dejean, Alain

    2010-02-01

    In Oecophylla, an ant genus comprising two territorially dominant arboreal species, workers are known to (1) use anal spots to mark their territories, (2) drag their gaster along the substrate to deposit short-range recruitment trails, and (3) drag the extruded rectal gland along the substrate to deposit the trails used in long-range recruitment. Here we study an overlooked but important marking behavior in which O. longinoda workers first rub the underside of their mandibles onto the substrate, and then--in a surprising posture--tilt their head and also rub the upper side of their mandibles. We demonstrate that this behavior is used to recruit nestmates. Its frequency varies with the rate at which a new territory, a sugary food source, a prey item, or an alien ant are discovered. Microscopy analyses showed that both the upper side and the underside of the mandibles possess pores linked to secretory glands. So, by rubbing their mandibles onto the substrate, the workers probably spread a secretion from these glands that is involved in nestmate recruitment.

  6. An Overlooked Mandibular-Rubbing Behavior Used during Recruitment by the African Weaver Ant, Oecophylla longinoda

    PubMed Central

    Roux, Olivier; Billen, Johan; Orivel, Jérôme; Dejean, Alain

    2010-01-01

    In Oecophylla, an ant genus comprising two territorially dominant arboreal species, workers are known to (1) use anal spots to mark their territories, (2) drag their gaster along the substrate to deposit short-range recruitment trails, and (3) drag the extruded rectal gland along the substrate to deposit the trails used in long-range recruitment. Here we study an overlooked but important marking behavior in which O. longinoda workers first rub the underside of their mandibles onto the substrate, and then—in a surprising posture—tilt their head and also rub the upper side of their mandibles. We demonstrate that this behavior is used to recruit nestmates. Its frequency varies with the rate at which a new territory, a sugary food source, a prey item, or an alien ant are discovered. Microscopy analyses showed that both the upper side and the underside of the mandibles possess pores linked to secretory glands. So, by rubbing their mandibles onto the substrate, the workers probably spread a secretion from these glands that is involved in nestmate recruitment. PMID:20126536

  7. Fire Ant Allergy

    MedlinePlus

    ... Serious Reaction For people with fire ant allergy, stings may cause a life-threatening reaction called anaphylaxis ( ... Fire ants bite with their jaws while they sting. This allows them to pull the stinger out, ...

  8. The Genome Sequence of the Leaf-Cutter Ant Atta cephalotes Reveals Insights into Its Obligate Symbiotic Lifestyle

    PubMed Central

    Suen, Garret; Holt, Carson; Abouheif, Ehab; Bornberg-Bauer, Erich; Bouffard, Pascal; Caldera, Eric J.; Cash, Elizabeth; Cavanaugh, Amy; Denas, Olgert; Elhaik, Eran; Favé, Marie-Julie; Gadau, Jürgen; Gibson, Joshua D.; Graur, Dan; Grubbs, Kirk J.; Hagen, Darren E.; Harkins, Timothy T.; Helmkampf, Martin; Hu, Hao; Johnson, Brian R.; Kim, Jay; Marsh, Sarah E.; Moeller, Joseph A.; Muñoz-Torres, Mónica C.; Murphy, Marguerite C.; Naughton, Meredith C.; Nigam, Surabhi; Overson, Rick; Rajakumar, Rajendhran; Reese, Justin T.; Scott, Jarrod J.; Smith, Chris R.; Tao, Shu; Tsutsui, Neil D.; Viljakainen, Lumi; Wissler, Lothar; Yandell, Mark D.; Zimmer, Fabian; Taylor, James; Slater, Steven C.; Clifton, Sandra W.; Warren, Wesley C.; Elsik, Christine G.; Smith, Christopher D.; Weinstock, George M.; Gerardo, Nicole M.; Currie, Cameron R.

    2011-01-01

    Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host–microbe symbioses. PMID:21347285

  9. The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle.

    PubMed

    Suen, Garret; Teiling, Clotilde; Li, Lewyn; Holt, Carson; Abouheif, Ehab; Bornberg-Bauer, Erich; Bouffard, Pascal; Caldera, Eric J; Cash, Elizabeth; Cavanaugh, Amy; Denas, Olgert; Elhaik, Eran; Favé, Marie-Julie; Gadau, Jürgen; Gibson, Joshua D; Graur, Dan; Grubbs, Kirk J; Hagen, Darren E; Harkins, Timothy T; Helmkampf, Martin; Hu, Hao; Johnson, Brian R; Kim, Jay; Marsh, Sarah E; Moeller, Joseph A; Muñoz-Torres, Mónica C; Murphy, Marguerite C; Naughton, Meredith C; Nigam, Surabhi; Overson, Rick; Rajakumar, Rajendhran; Reese, Justin T; Scott, Jarrod J; Smith, Chris R; Tao, Shu; Tsutsui, Neil D; Viljakainen, Lumi; Wissler, Lothar; Yandell, Mark D; Zimmer, Fabian; Taylor, James; Slater, Steven C; Clifton, Sandra W; Warren, Wesley C; Elsik, Christine G; Smith, Christopher D; Weinstock, George M; Gerardo, Nicole M; Currie, Cameron R

    2011-02-10

    Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.

  10. Ecological stoichiometry of ants in a New World rain forest.

    PubMed

    Davidson, Diane W

    2005-01-01

    C:N stoichiometry was investigated in relation to diet (delta(15)N), N-deprivation, and worker body size for a diverse assemblage of tropical Amazonian ants. Relative nitrogen (N) deprivation was assayed for 54 species as an exchange ratio (ER), defined as SUCmin/AAmin, or the minimum sucrose concentration, divided by the minimum amino acid concentration, accepted as food by >/=50% of tested workers. On average, N-deprivation (ER) was almost fivefold greater for N-omnivorous and N-herbivorous (N-OH) taxa than for N-carnivores. In two-way ANOVAs at three taxonomic levels (species and species groups, genera, and tribes), higher ER was associated with small body size and (marginally) with less carnivorous diets. ERs did not differ systematically between trophobiont-tending and "leaf-foraging" functional groups, but specialized wound-feeders and coccid-tenders were prominent among high ER taxa. Paradoxically, some high ER taxa were among the most predatory members of their genera or subfamilies. Biomass % N was lower in N-OH taxa than in carnivores and varied inversely with N-deprivation (log ER) in the former taxa only. In an expanded data set, N-content increased allometrically in N-OHs, N-carnivores, and all ants combined, and with carnivory in large-bodied ants only. Exceptional taxa included small-bodied and predaceous Wasmannia, with high % N despite high ER, and Linepithema, with the lowest % N despite high delta(15)N. Patterns in C:N stoichiometry are explained largely at the genus level and above by elemental composition of alarm/defensive/offensive chemical weaponry and, perhaps in some cases, by reduced N investment in cuticle in taxa with high surface:volume ratios. Several consequences of C:N stoichiometry identify Azteca, and possibly Crematogaster, as taxa preadapted for their roles as prominent associates of myrmecophytes. C:N stoichiometry of ants should be incorporated into models of strategic colony design and examined in a phylogenetic context as

  11. Congestion and communication in confined ant traffic

    NASA Astrophysics Data System (ADS)

    Gravish, Nick; Gold, Gregory; Zangwill, Andrew; Goodisman, Michael A. D.; Goldman, Daniel I.

    2014-03-01

    Many social animals move and communicate within confined spaces. In subterranean fire ants Solenopsis invicta, mobility within crowded nest tunnels is important for resource and information transport. Within confined tunnels, communication and traffic flow are at odds: trafficking ants communicate through tactile interactions while stopped, yet ants that stop to communicate impose physical obstacles on the traffic. We monitor the bi-directional flow of fire ant workers in laboratory tunnels of varied diameter D. The persistence time of communicating ant aggregations, τ, increases approximately linearly with the number of participating ants, n. The sensitivity of traffic flow increases as D decreases and diverges at a minimum diameter, Dc. A cellular automata model incorporating minimal traffic features--excluded volume and communication duration--reproduces features of the experiment. From the model we identify a competition between information transfer and the need to maintain jam-free traffic flow. We show that by balancing information transfer and traffic flow demands, an optimum group strategy exists which maximizes information throughput. We acknowledge funding from NSF PoLS #0957659 and #PHY-1205878.

  12. Indirect defense in a highly specific ant-plant mutualism.

    PubMed

    Grangier, Julien; Dejean, Alain; Malé, Pierre-Jean G; Orivel, Jérôme

    2008-10-01

    Although associations between myrmecophytes and their plant ants are recognized as a particularly effective form of protective mutualism, their functioning remains incompletely understood. This field study examined the ant-plant Hirtella physophora and its obligate ant associate Allomerus decemarticulatus. We formulated two hypotheses on the highly specific nature of this association: (1) Ant presence should be correlated with a marked reduction in the amount of herbivory on the plant foliage; (2) ant activity should be consistent with the "optimal defense" theory predicting that the most vulnerable and valuable parts of the plant are the best defended. We validated the first hypothesis by demonstrating that for ant-excluded plants, expanding leaves, but also newly matured ones in the long term, suffered significantly more herbivore damage than ant-inhabited plants. We showed that A. decemarticulatus workers represent both constitutive and inducible defenses for their host, by patrolling its foliage and rapidly recruiting nestmates to foliar wounds. On examining how these activities change according to the leaves' developmental stage, we found that the number of patrolling ants dramatically decreased as the leaves matured, while leaf wounds induced ant recruitment regardless of the leaf's age. The resulting level of these indirect defenses was roughly proportional to leaf vulnerability and value during its development, thus validating our second hypothesis predicting optimal protection. This led us to discuss the factors influencing ant activity on the plant's surface. Our study emphasizes the importance of studying both the constitutive and inducible components of indirect defense when evaluating its efficacy and optimality.

  13. Bait distribution among multiple colonies of Pharaoh ants (hymenoptera: Formicidae).

    PubMed

    Oi, D H; Vail, K M; Williams, D F

    2000-08-01

    Pharaoh ant, Monomorium pharaonis (L.), infestations often consist of several colonies located at different nest sites. To achieve control, it is desirable to suppress or eliminate the populations of a majority of these colonies. We compared the trophallactic distribution and efficacy of two ant baits, with different modes of action, among groups of four colonies of Pharaoh ants. Baits contained either the metabolic-inhibiting active ingredient hydramethylnon or the insect growth regulator (IGR) pyriproxyfen. Within 3 wk, the hydramethylnon bait reduced worker and brood populations by at least 80%, and queen reductions ranged between 73 and 100%, when nests were in proximity (within 132 cm) to the bait source. However, these nest sites were reoccupied by ants from other colonies located further from the bait source. The pyriproxyfen bait was distributed more thoroughly to all nest locations with worker populations gradually declining by 73% at all nest sites after 8 wk. Average queen reductions ranged from 31 to 49% for all nest sites throughout the study. Even though some queens survived, brood reductions were rapid in the pyriproxyfen treatment, with reductions of 95% at all locations by week 3. Unlike the metabolic inhibitor, the IGR did not kill adult worker ants quickly, thus, more surviving worker ants were available to distribute the bait to all colonies located at different nest sites. Thus, from a single bait source, the slow-acting bait toxicant provided gradual, but long-term control, whereas the fast-acting bait toxicant provided rapid, localized control for a shorter duration.

  14. Thermal radiation as a learned orientation cue in leaf-cutting ants (Atta vollenweideri).

    PubMed

    Kleineidam, C J; Ruchty, M; Casero-Montes, Z A; Roces, F

    2007-05-01

    We explored the ability of leaf-cutting ants (Atta vollenweideri) to learn the location of a food reward by using thermal information as an orientation cue. During training of single workers, the conditioned stimulus was a distant thermal source placed frontally, 15 mm away from a platform having a leaf fragment as reward. After training, single workers were confronted with the choice between two sides, one being coupled, in a pseudo-randomized design, with a thermal stimulus heated 5 degrees C above environmental temperature. After 10 learning trials, workers significantly chose the side with the thermal stimulus. This showed that workers can use thermal information for spatial orientation in the context of foraging, which may help them to locate, for instance, highly attractive sun-exposed leaves. Thermal radiation alone as orientation cue was sufficient to allow learning, since preclusion of thermal convection during training and test did not impair workers' response. Shielding of both thorax and gaster from the thermal source did not weaken learning, suggesting the sole participation of head and antennae in temperature reception. A thermal stimulus heated 1 degrees C above environmental temperature could not be used as a learned orientation cue, even when foragers were allowed to directly contact the thermal source.

  15. Ant Colony Optimization Algorithm for Continuous Domains Based on Position Distribution Model of Ant Colony Foraging

    PubMed Central

    Liu, Liqiang; Dai, Yuntao

    2014-01-01

    Ant colony optimization algorithm for continuous domains is a major research direction for ant colony optimization algorithm. In this paper, we propose a distribution model of ant colony foraging, through analysis of the relationship between the position distribution and food source in the process of ant colony foraging. We design a continuous domain optimization algorithm based on the model and give the form of solution for the algorithm, the distribution model of pheromone, the update rules of ant colony position, and the processing method of constraint condition. Algorithm performance against a set of test trials was unconstrained optimization test functions and a set of optimization test functions, and test results of other algorithms are compared and analyzed to verify the correctness and effectiveness of the proposed algorithm. PMID:24955402

  16. Ant colony optimization algorithm for continuous domains based on position distribution model of ant colony foraging.

    PubMed

    Liu, Liqiang; Dai, Yuntao; Gao, Jinyu

    2014-01-01

    Ant colony optimization algorithm for continuous domains is a major research direction for ant colony optimization algorithm. In this paper, we propose a distribution model of ant colony foraging, through analysis of the relationship between the position distribution and food source in the process of ant colony foraging. We design a continuous domain optimization algorithm based on the model and give the form of solution for the algorithm, the distribution model of pheromone, the update rules of ant colony position, and the processing method of constraint condition. Algorithm performance against a set of test trials was unconstrained optimization test functions and a set of optimization test functions, and test results of other algorithms are compared and analyzed to verify the correctness and effectiveness of the proposed algorithm.

  17. How to be an ant on figs

    NASA Astrophysics Data System (ADS)

    Bain, Anthony; Harrison, Rhett D.; Schatz, Bertrand

    2014-05-01

    Mutualistic interactions are open to exploitation by one or other of the partners and a diversity of other organisms, and hence are best understood as being embedded in a complex network of biotic interactions. Figs participate in an obligate mutualism in that figs are dependent on agaonid fig wasps for pollination and the wasps are dependent on fig ovules for brood sites. Ants are common insect predators and abundant in tropical forests. Ants have been recorded on approximately 11% of fig species, including all six subgenera, and often affect the fig-fig pollinator interaction through their predation of either pollinating and parasitic wasps. On monoecious figs, ants are often associated with hemipterans, whereas in dioecious figs ants predominantly prey on fig wasps. A few fig species are true myrmecophytes, with domatia or food rewards for ants, and in at least one species this is linked to predation of parasitic fig wasps. Ants also play a role in dispersal of fig seeds and may be particularly important for hemi-epiphytic species, which require high quality establishment microsites in the canopy. The intersection between the fig-fig pollinator and ant-plant systems promises to provide fertile ground for understanding mutualistic interactions within the context of complex interaction networks.

  18. Fatty Amines from Little Black Ants, Monomorium minimum, and Their Biological Activities Against Red Imported Fire Ants, Solenopsis invicta.

    PubMed

    Wang, Lei; Chen, Jian

    2015-08-01

    Red imported fire ants, Solenopsis invicta, are significant invasive pests. Certain native ant species can compete with S. invicta, such as the little black ant, Monomorium minimum. Defensive secretions may contribute to the competition capacity of native ants. The chemistry of ant defensive secretions in the genus Monomorium has been subjected to extensive research. The insecticidal alkaloids, 2,5-dialkyl-pyrrolidines and 2,5-dialkyl-pyrrolines have been reported to dominate the venom of M. minimum. In this study, analysis of defensive secretions of workers and queens of M. minimum revealed two primary amines, decylamine and dodecylamine. Neither amine has been reported previously from natural sources. Toxicity and digging suppression by these two amines against S. invicta were examined. Decylamine had higher toxicity to S. invicta workers than dodecylamine, a quicker knockdown effect, and suppressed the digging behavior of S. invicta workers at lower concentration. However, the amount of fatty amines in an individual ant was not enough to knockdown a fire ant or suppress its digging behavior. These amines most likely work in concert with other components in the chemical defense of M. minimum.

  19. Evolution of social parasitism in ants: size of sexuals, sex ratio and mechanisms of caste determination

    PubMed Central

    Aron, S.; Passera, L.; Keller, L.

    1999-01-01

    Social parasitism, one of the most intriguing phenomena in ants, has evolved to various levels, the most extreme form being parasites that have lost the worker caste and rely completely on the host's worker force to raise their brood. A remarkable feature of workerless social parasites is the small size of sexuals. It has been suggested that reduced size evolved as a means to take advantage of the host's caste-determination system, so that parasite larvae develop into sexuals with less food than is required to produce host workers. An important consequence of size reduction is that it might restrict the host workers' ability to discriminate between the brood of the social parasite and their own brood and might protect parasite sexuals from elimination. We found that sexuals of the workerless inquiline ant Plagiolepis xene were significantly smaller than the sexuals of their host Plagiolepis pygmaea, but remarkably similar to the host workers. The size variance of parasite sexuals was much lower than that of their host; this result possibly suggests that there is very stabilizing selection acting on size of the parasite sexuals. Comparison of the primary (egg) and secondary (adult) sex ratios of the parasite and host showed that miniaturization of P. xene sexuals has been accompanied by their ability to develop into sexuals even when the host P. pygmaea actively prevents production of its own sexuals. These results suggest that the inquiline's size and caste threshold have been reduced such that all individuals in a parasite brood will develop into sexuals. We also found that the adult sex ratio of P. xene was heavily female-biased. This bias probably stems from local mate competition that arises from sexuals mating within the nest. There was no significant difference between the proportion of haploid eggs and adult males produced; this observation indicates that a female-biased sex ratio is achieved by queens producing a higher proportion of diploid eggs rather

  20. A mathematical model of foraging in a dynamic environment by trail-laying Argentine ants.

    PubMed

    Ramsch, Kai; Reid, Chris R; Beekman, Madeleine; Middendorf, Martin

    2012-08-07

    Ants live in dynamically changing environments, where food sources become depleted and alternative sources appear. Yet most mathematical models of ant foraging assume that the ants' foraging environment is static. Here we describe a mathematical model of ant foraging in a dynamic environment. Our model attempts to explain recent empirical data on dynamic foraging in the Argentine ant Linepithema humile (Mayr). The ants are able to find the shortest path in a Towers of Hanoi maze, a complex network containing 32,768 alternative paths, even when the maze is altered dynamically. We modify existing models developed to explain ant foraging in static environments, to elucidate what possible mechanisms allow the ants to quickly adapt to changes in their foraging environment. Our results suggest that navigation of individual ants based on a combination of one pheromone deposited during foraging and directional information enables the ants to adapt their foraging trails and recreates the experimental results. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Ants at Plant Wounds: A Little-Known Trophic Interaction with Evolutionary Implications for Ant-Plant Interactions.

    PubMed

    Staab, Michael; Fornoff, Felix; Klein, Alexandra-Maria; Blüthgen, Nico

    2017-09-01

    Extrafloral nectaries (EFNs) allow plants to engage in mutualisms with ants, preventing herbivory in exchange for food. EFNs occur scattered throughout the plant phylogeny and likely evolved independent from herbivore-created wounds subsequently visited by ants collecting leaked sap. Records of wound-feeding ants are, however, anecdotal. By surveying 38,000 trees from 40 species, we conducted the first quantitative ecological study of this overlooked behavior. Ant-wound interactions were widespread (0.5% of tree individuals) and occurred on 23 tree species. Interaction networks were opportunistic, closely resembling ant-EFN networks. Fagaceae, a family lacking EFNs, was strongly overrepresented. For Fagaceae, ant occurrence at wounds correlated with species-level leaf damage, potentially indicating that wounds may attract mutualistic ants, which supports the hypothesis of ant-tended wounds as precursors of ant-EFN mutualisms. Given that herbivore wounds are common, wound sap as a steadily available food source might further help to explain the overwhelming abundance of ants in (sub)tropical forest canopies.

  2. [Ants: species-area relationship in tropical dry forest fragments].

    PubMed

    Lozano-Zambrano, Fabio H; Ulloa-Chacón, Patricia; Armbrecht, Inge

    2009-01-01

    We analyzed the effect of fragmentation on ant species-area and specimen frequency-area relationships in nine patches of tropical dry forest in the middle Cauca river basin in Colombia. Species richness and specimen relative frequency of ants were positively correlated with area, whereas no significant correlation was found between species richness and the degree of isolation calculated for the forest patches. As the fragmentation affects different functional groups in different ways, we analyzed the species-area relationship for separate functional groups of ants. According to the habitat requirements we found that the species richness increased faster as area increased for ants inhabiting decomposing wood, followed by ants associated with trees, while species richness of ants living under dead leaves did not correlate with area. According to the food preference, species richness was positively correlated with area for the army ant group, while no significant correlation was found for solitary hunters or for leaf-cutting ants. Ant species richness and specimen density were calculated from equal size samples and examined in relation to the habitat area. An inverse correlation was found only for specimen density, the opposite of what was expected. To our knowledge this is one of the first studies showing differential responses of functional groups of ants to habitat loss. Moreover, it emphasizes the conservation value of small forest fragments for ants in a tropical dry forest.

  3. Colony structure in a plant-ant: behavioural, chemical and genetic study of polydomy in Cataulacus mckeyi (Myrmicinae).

    PubMed

    Debout, Gabriel; Provost, Erick; Renucci, Marielle; Tirard, Alain; Schatz, Bertrand; McKey, Doyle

    2003-10-01

    Social organisation of colonies of obligate plant-ants can affect their interaction with myrmecophyte hosts and with other ants competing for the resources they offer. An important parameter of social organisation is whether nest sites of a colony include one or several host individuals. We determined colony boundaries in a plant-ant associated with the rainforest understorey tree Leonardoxa africana subsp. africana, found in coastal forests of Cameroon (Central Africa). This myrmecophyte is strictly associated with two ants, Petalomyrmex phylax and Cataulacus mckeyi. Plants provide food and nesting sites for P. phylax, which protects young leaves against insect herbivores. This mutualism is often parasitised by C. mckeyi, which uses but does not protect the host. The presence of C. mckeyi on a tree excludes the mutualistic ant. Because Petalomyrmex-occupied trees are better protected, their growth and survival are superior to those of Cataulacus-occupied trees, giving P. phylax an advantage in occupation of nest sites. C. mckeyi often colonises trees that have lost their initial associate P. phylax, as a result of injury to the tree caused by disturbance. Polydomy may allow C. mckeyi to occupy small clumps of trees, without the necessity of claustral colony foundation in each tree. Investigating both the proximate (behavioural repertoire, colony odour) and the ultimate factors (genetic structure) that may influence colony closure, we precisely defined colony boundaries. We show that colonies of C. mckeyi are monogynous and facultatively polydomous, i.e. a colony occupies one to several Leonardoxa trees. Workers do not produce males. Thus, the hypothesis that polydomy allows workers in queenless nests to evade queen control for their reproduction is not supported in this instance. This particular colony structure may confer on C. mckeyi an advantage in short-distance dispersal, and this could help explain its persistence within the dynamic Leonardoxa system.

  4. Efforts to eradicate yellow crazy ants on Johnston Atoll: Results from Crazy Ant Strike Team IX, December 2014-June 2015

    USGS Publications Warehouse

    Banko, Paul C.; Peck, Robert W.; Donmoyer, Kevin; Kropidlowski, Stephan; Pollock, Amanda

    2015-01-01

    The ecologically destructive yellow crazy ant (YCA; Anoplolepis gracilipes) was first detected on Johnston Atoll in January 2010. Within eight months, the U.S. Fish and Wildlife Service had mobilized its first crazy ant strike team (CAST), a group of biologists dedicated to testing and identifying insecticidal baits to be used to eradicate the ant on the atoll. During December 2014‒May 2015 CAST IX focused on testing hydrogel crystals saturated with sucrose solution (25%) carrying the insecticides thiamethoxam and dinotefuran against YCA. A series of experiments, including artificial nest box trials, and field-based palatability trials and eradication tests on small (500 m2 or 0.05 ha) and large plots (2500 m2 or 0.25 ha), were conducted to test concentrations of thiamethoxam ranging from 0.0005% to 0.01%, and dinotefuran at 0.05%. Additionally, the cat food-based matrix containing dinotefuran (0.05%), the standard bait used to suppress YCA on Johnston since 2011, and textured vegetable protein (TVP) carrying dinotefuran at 0.1% and 0.05% were included in large plot tests. Nest box trials were inconclusive due to a consistent loss of queen and worker ants in control boxes, so they were discontinued. Palatability trials suggested higher dosages of thiamethoxam (0.005 and 0.01%) were less attractive than lower dosages (0.0005 and 0.001%) and controls (sucrose only), but small and large plot experiments failed to identify a thiamethoxam concentration that was consistently effective at killing YCA. In contrast, hydrogel containing dinotefuran was consistently effective, killing >95% of YCA on small and large plots. As expected, the cat food bait effectively reduced YCA abundances, but was slightly less effective than hydrogel containing dinotefuran over time. Three successive, approximately weekly treatments of large plots with hydrogel bait, or other baits followed by hydrogel bait, suggest an increasing overall effectiveness, with no aversion of YCA to the bait

  5. Acoustic communication by ants

    NASA Astrophysics Data System (ADS)

    Hickling, Robert

    2002-05-01

    Many ant species communicate acoustically by stridulating, i.e., running a scraper over a washboard-like set of ridges. Ants appear to be insensitive to airborne sound. Consequently, myrmecologists have concluded that the stridulatory signals are transmitted through the substrate. This has tended to diminish the importance of acoustic communication, and it is currently believed that ant communication is based almost exclusively on pheromones, with acoustic communication assigned an almost nonexistent role. However, it can be shown that acoustic communication between ants is effective only if the medium is air and not the substrate. How, then, is it possible for ants to appear deaf to airborne sound and yet communicate through the air? An explanation is provided in a paper [R. Hickling and R. L. Brown, ``Analysis of acoustic communication by ants,'' J. Acoust. Soc. Am. 108, 1920-1929 (2000)]. Ants are small relative to the wavelengths they generate. Hence, they create a near field, which is characterized by a major increase in sound velocity (particle velocity of sound) in the vicinity of the source. Hair sensilla on the ants' antennae respond to sound velocity. Thus, ants are able to detect near-field sound from other ants and to exclude extraneous airborne sound.

  6. Operant conditioning in the ant Myrmica sabuleti.

    PubMed

    Cammaerts, M C

    2004-11-30

    Operant conditioning could be obtained in the ant Myrmica sabuleti by presenting to the workers, during a six-day period, an apparatus containing either sugared water or meat as a reward. The conditioning obtained using sugared water as a reward was short lasting. A reconditioning was more persistent and lasted four hours. The ants' response was very precise, since they exhibited it only in front of an apparatus identical to that used during the training phase. Operant conditioning obtained using meat as a reward was more pronounced than that obtained by using sugared water, probably because meat is more valuable as a reward than sugar for the species studied, which is essentially a carnivorous one. Such a conditioning was rather persistent. Indeed, a first operant conditioning obtained by using meat as a reward could still be detected after seven hours, and a reconditioning was still significant after eight hours. One day after this eight-hour period without rewarding the ants, the response was higher again and a further day later, it was still significant. Since the operant conditioning is easy to perform and quantify and since the ants' response is very precise, such a conditioning can be used for further studying M. sabuleti workers' visual perception.

  7. Workers intake too much salt from dishes of eating out and food service cafeterias; direct chemical analysis of sodium content.

    PubMed

    Park, Hae-Ryun; Jeong, Gye-Ok; Lee, Seung-Lim; Kim, Jin-Young; Kang, Soon-Ah; Park, Kun-Young; Ryou, Hyun-Joo

    2009-01-01

    The average sodium intake of Koreans was reported to be 5,279.9 mg/day, which is one of the highest intake levels worldwide. The average Koreans intake 19.6% of sodium from kimchi, showing kimchi as the main contributor of sodium in this country (Ministry of Health and Welfare, 2005). The sodium content of dishes that are frequently chosen by workers, and which were served by foodservice cafeterias were chemically analyzed. The average sodium content of one meal provided by 10 foodservice cafeterias was 2,777.7 mg. Twenty-one, one-dish-meals, frequently chosen by workers for a lunch menu, were collected at 4 different restaurants for each menu by one male, aged in the twenties and analyzed chemically also. Workers who eat lunch at a workplace cafeteria everyday could intake about 8 g of salt at a one-time meal and those who eat out for a one-dish-meal would intake 3-8 g of salt without counting sodium content from the side dishes. From these study results, one could estimate that over 10 g of salt could be possible for a single meal for workers who eat out everyday. A nationwide nutrition campaign and education for low salt diets for restaurant owners and foodservice providers should be seriously considered.

  8. Specialization and group size: brain and behavioural correlates of colony size in ants lacking morphological castes

    PubMed Central

    Amador-Vargas, Sabrina; Gronenberg, Wulfila; Wcislo, William T.; Mueller, Ulrich

    2015-01-01

    Group size in both multicellular organisms and animal societies can correlate with the degree of division of labour. For ants, the task specialization hypothesis (TSH) proposes that increased behavioural specialization enabled by larger group size corresponds to anatomical specialization of worker brains. Alternatively, the social brain hypothesis proposes that increased levels of social stimuli in larger colonies lead to enlarged brain regions in all workers, regardless of their task specialization. We tested these hypotheses in acacia ants (Pseudomyrmex spinicola), which exhibit behavioural but not morphological task specialization. In wild colonies, we marked, followed and tested ant workers involved in foraging tasks on the leaves (leaf-ants) and in defensive tasks on the host tree trunk (trunk-ants). Task specialization increased with colony size, especially in defensive tasks. The relationship between colony size and brain region volume was task-dependent, supporting the TSH. Specifically, as colony size increased, the relative size of regions within the mushroom bodies of the brain decreased in trunk-ants but increased in leaf-ants; those regions play important roles in learning and memory. Our findings suggest that workers specialized in defence may have reduced learning abilities relative to leaf-ants; these inferences remain to be tested. In societies with monomorphic workers, brain polymorphism enhanced by group size could be a mechanism by which division of labour is achieved. PMID:25567649

  9. Specialization and group size: brain and behavioural correlates of colony size in ants lacking morphological castes.

    PubMed

    Amador-Vargas, Sabrina; Gronenberg, Wulfila; Wcislo, William T; Mueller, Ulrich

    2015-02-22

    Group size in both multicellular organisms and animal societies can correlate with the degree of division of labour. For ants, the task specialization hypothesis (TSH) proposes that increased behavioural specialization enabled by larger group size corresponds to anatomical specialization of worker brains. Alternatively, the social brain hypothesis proposes that increased levels of social stimuli in larger colonies lead to enlarged brain regions in all workers, regardless of their task specialization. We tested these hypotheses in acacia ants (Pseudomyrmex spinicola), which exhibit behavioural but not morphological task specialization. In wild colonies, we marked, followed and tested ant workers involved in foraging tasks on the leaves (leaf-ants) and in defensive tasks on the host tree trunk (trunk-ants). Task specialization increased with colony size, especially in defensive tasks. The relationship between colony size and brain region volume was task-dependent, supporting the TSH. Specifically, as colony size increased, the relative size of regions within the mushroom bodies of the brain decreased in trunk-ants but increased in leaf-ants; those regions play important roles in learning and memory. Our findings suggest that workers specialized in defence may have reduced learning abilities relative to leaf-ants; these inferences remain to be tested. In societies with monomorphic workers, brain polymorphism enhanced by group size could be a mechanism by which division of labour is achieved.

  10. Effects of desiccation and starvation on thermal tolerance and the heat-shock response in forest ants.

    PubMed

    Nguyen, Andrew D; DeNovellis, Kerri; Resendez, Skyler; Pustilnik, Jeremy D; Gotelli, Nicholas J; Parker, Joel D; Cahan, Sara Helms

    2017-04-24

    Temperature increases associated with global climate change are likely to be accompanied by additional environmental stressors such as desiccation and food limitation, which may alter how temperature impacts organismal performance. To investigate how interactions between stressors influence thermal tolerance in the common forest ant, Aphaenogaster picea, we compared the thermal resistance of workers to heat shock with and without pre-exposure to desiccation or starvation stress. Knockdown (KD) time at 40.5 °C of desiccated ants was reduced 6% compared to controls, although longer exposure to desiccation did not further reduce thermal tolerance. Starvation, in contrast, had an increasingly severe effect on thermal tolerance: at 21 days, average KD time of starved ants was reduced by 65% compared to controls. To test whether reduction in thermal tolerance results from impairment of the heat-shock response, we measured basal gene expression and transcriptional induction of two heat-shock proteins (hsp70 and hsp40) in treated and control ants. We found no evidence that either stressor impaired the Hsp response: both desiccation and starvation slightly increased basal Hsp expression under severe stress conditions and did not affect the magnitude of induction under heat shock. These results suggest that the co-occurrence of multiple environmental stressors predicted by climate change models may make populations more vulnerable to future warming than is suggested by the results of single-factor heating experiments.

  11. Electroantennogram and behavioral responses of the imported fire ant, Solenopsis invicta Buren, to an alarm pheromone component and its analogues.

    PubMed

    Guan, Di; Lu, Yong-Yue; Liao, Xiao-Lan; Wang, Lei; Chen, Li

    2014-12-10

    A characteristic behavior in ants is to move rapidly to emission sources of alarm pheromones. The addition of ant alarm pheromones to bait is expected to enhance its attractiveness. To search for candidate compounds for bait enhancement in fire ant control, 13 related alkylpyrazine analogues in addition to synthetic alarm pheromone component were evaluated for electroantennogram (EAG) and behavioral activities in Solenopsis invicta. Most compounds elicited dose-dependent EAG and behavioral responses. There exists a correlation between the EAG and behavioral responses. Among the 14 tested alkylpyrazines, three compounds, 2-ethyl-3,6(5)-dimethyl pyrazine (1), 2,3,5-trimethylpyrazine (7), and 2,3-diethyl-5-methylpyrazine (12), elicited significant alarm responses at a dose range of 0.1-1000 ng. Further bait discovery bioassay with the three most active alkylpyrazines demonstrated that food bait accompanied by sample-treated filter paper disk attracted significantly more fire ant workers in the first 15 min period. EAG and behavioral bioassays with pure pheromone isomers accumulated by semi-preparative high-performance liquid chromatography demonstrated that 2-ethyl-3,6-dimethylpyrazine was significantly more active than 2-ethyl-3,5-dimethylpyrazine.

  12. Kin-informative recognition cues in ants.

    PubMed

    Nehring, Volker; Evison, Sophie E F; Santorelli, Lorenzo A; d'Ettorre, Patrizia; Hughes, William O H

    2011-07-07

    Although social groups are characterized by cooperation, they are also often the scene of conflict. In non-clonal systems, the reproductive interests of group members will differ and individuals may benefit by exploiting the cooperative efforts of other group members. However, such selfish behaviour is thought to be rare in one of the classic examples of cooperation--social insect colonies--because the colony-level costs of individual selfishness select against cues that would allow workers to recognize their closest relatives. In accord with this, previous studies of wasps and ants have found little or no kin information in recognition cues. Here, we test the hypothesis that social insects do not have kin-informative recognition cues by investigating the recognition cues and relatedness of workers from four colonies of the ant Acromyrmex octospinosus. Contrary to the theoretical prediction, we show that the cuticular hydrocarbons of ant workers in all four colonies are informative enough to allow full-sisters to be distinguished from half-sisters with a high accuracy. These results contradict the hypothesis of non-heritable recognition cues and suggest that there is more potential for within-colony conflicts in genetically diverse societies than previously thought.

  13. Shaken, not stirred: a serendipitous study of ants and earthquakes.

    PubMed

    Lighton, John R B; Duncan, Frances D

    2005-08-01

    There is anecdotal evidence for profound behavioral changes prior to and during earthquakes in many organisms, including arthropods such as ants. Behavioral or physiological analysis has often, in light of these reports, been proposed as a means of earthquake prediction. We report here a serendipitous study of the effect of the powerful Landers earthquake in the Mojave Desert, USA (Richter magnitude 7.4) on ant trail dynamics and aerobic catabolism in the desert harvester ant Messor pergandei. We monitored trail traffic rates to and from the colony, trail speed, worker mass distributions, rates of aerobic catabolism and temperature at ant height before and during the earthquake, and for 3 days after the earthquake. Contrary to anecdotal reports of earthquake effects on ant behavior, the Landers earthquake had no effect on any measured aspect of the physiology or behavior of M. pergandei. We conclude that anecdotal accounts of the effects of earthquakes or their precursors on insect behavior should be interpreted with caution.

  14. Ecological consequences of traffic organisation in ant societies

    NASA Astrophysics Data System (ADS)

    Burd, Martin

    2006-12-01

    Many species of ants engage in social foraging in which traffic develops over pathways defined by pheromones or physical roads cleared through debris. Worker ants from the same colony have a common underlying evolutionary interest in their collective performance. Thus, ant traffic makes an interesting comparison to other kinds of cellular or organismal traffic composed of elements with varying degrees of shared or disparate goals. Recent studies have revealed how small-scale interactions among ants amplify to create large-scale traffic structure, such as segregation of counterflows. However, much less is known about the ecological costs and benefits of different kinds of traffic organization. The common assumption that maximum traffic flux provides maximum ecological benefit needs closer scrutiny. Ant traffic provides a potentially useful model system for experimental study of crowd panics, and for assessing the role of transport networks in creating scaling relationships between the size and activity rates of the entities they serve.

  15. Parasitoids deter foraging by Argentine ants (Linepithema humile) in their native habitat in Brazil.

    PubMed

    Orr, Matthew R; Seike, Sergio H

    1998-12-01

    The Argentine ant, Linepithema humile, has invaded sites across Africa, Australia, Europe, and North America. In its introduced ranges it eliminates native ants and tends agricultural pests. Few studies have examined the ecology of Argentine ants in their native habitat. This study examined the effects of parasitoid flies, genus Pseudacteon, on the foraging behavior of Argentine ants in part of their native range in southern Brazil. Pseudacteon parasitoids commonly attacked Argentine ants, but not other ant species, in daylight at temperatures above 18°C. Argentine ants abandoned food resources and returned underground in the presence of parasitoids. Parasitoid attack rates diminished as Argentine ants retreated underground. Where parasitoids were present, Argentine ants were abundant at food resources only during times of day when parasitoids were inactive. Where parasitoids were absent, Argentine ants were abundant at food resources throughout the day. Overall, the presence of parasitoids explained observed variation in Argentine ant foraging far better than temperature, although temperature had some effect. The results suggest that Pseudacteon parasitoids inhibit the ability of Argentine ants to gather food resources in their native habitat in Brazil.

  16. Special Issue: Rural Workers.

    ERIC Educational Resources Information Center

    Goodson, Elizabeth; And Others

    1995-01-01

    The issue discusses the role of the International Labour Office in the field of workers' education for rural workers and their organizations. Articles discuss labor conditions, child labor in agriculture, gender and equality training, trade unions, fair trade, and changing patterns of food production. Appendixes include information about…

  17. Special Issue: Rural Workers.

    ERIC Educational Resources Information Center

    Goodson, Elizabeth; And Others

    1995-01-01

    The issue discusses the role of the International Labour Office in the field of workers' education for rural workers and their organizations. Articles discuss labor conditions, child labor in agriculture, gender and equality training, trade unions, fair trade, and changing patterns of food production. Appendixes include information about…

  18. The effects of fire on ant trophic assemblage and sex allocation

    PubMed Central

    Caut, Stephane; Jowers, Michael J; Arnan, Xavier; Pearce-Duvet, Jessica; Rodrigo, Anselm; Cerda, Xim; Boulay, Raphaël R

    2014-01-01

    Fire plays a key role in ecosystem dynamics worldwide, altering energy flows and species community structure and composition. However, the functional mechanisms underlying these effects are not well understood. Many ground-dwelling animal species can shelter themselves from exposure to heat and therefore rarely suffer direct mortality. However, fire-induced alterations to the environment may change a species' relative trophic level within a food web and its mode of foraging. We assessed how fire could affect ant resource utilization at different scales in a Mediterranean forest. First, we conducted isotopic analyses on entire ant species assemblages and their potential food resources, which included plants and other arthropods, in burned and unburned plots 1 year postfire. Second, we measured the production of males and females by nests of a fire-resilient species, Aphaenogaster gibbosa, and analyzed the differences in isotopic values among workers, males, and females to test whether fire constrained resource allocation. We found that, in spite of major modifications in biotic and abiotic conditions, fire had little impact on the relative trophic position of ant species. The studied assemblage was composed of species with a wide array of diets. They ranged from being mostly herbivorous to completely omnivorous, and a given species' trophic level was the same in burned and unburned plots. In A. gibbosa nests, sexuals had greater δ15N values than workers in both burned and unburned plots, which suggests that the former had a more protein-rich diet than the latter. Fire also appeared to have a major effect on A. gibbosa sex allocation: The proportion of nests that produced male brood was greater on burned zones, as was the mean number of males produced per nest with the same reproductive investment. Our results show that generalist ants with relatively broad diets maintained a constant trophic position, even following a major disturbance like fire. However, the

  19. The effects of fire on ant trophic assemblage and sex allocation.

    PubMed

    Caut, Stephane; Jowers, Michael J; Arnan, Xavier; Pearce-Duvet, Jessica; Rodrigo, Anselm; Cerda, Xim; Boulay, Raphaël R

    2014-01-01

    Fire plays a key role in ecosystem dynamics worldwide, altering energy flows and species community structure and composition. However, the functional mechanisms underlying these effects are not well understood. Many ground-dwelling animal species can shelter themselves from exposure to heat and therefore rarely suffer direct mortality. However, fire-induced alterations to the environment may change a species' relative trophic level within a food web and its mode of foraging. We assessed how fire could affect ant resource utilization at different scales in a Mediterranean forest. First, we conducted isotopic analyses on entire ant species assemblages and their potential food resources, which included plants and other arthropods, in burned and unburned plots 1 year postfire. Second, we measured the production of males and females by nests of a fire-resilient species, Aphaenogaster gibbosa, and analyzed the differences in isotopic values among workers, males, and females to test whether fire constrained resource allocation. We found that, in spite of major modifications in biotic and abiotic conditions, fire had little impact on the relative trophic position of ant species. The studied assemblage was composed of species with a wide array of diets. They ranged from being mostly herbivorous to completely omnivorous, and a given species' trophic level was the same in burned and unburned plots. In A. gibbosa nests, sexuals had greater δ(15)N values than workers in both burned and unburned plots, which suggests that the former had a more protein-rich diet than the latter. Fire also appeared to have a major effect on A. gibbosa sex allocation: The proportion of nests that produced male brood was greater on burned zones, as was the mean number of males produced per nest with the same reproductive investment. Our results show that generalist ants with relatively broad diets maintained a constant trophic position, even following a major disturbance like fire. However, the

  20. Filamentous fungi vectored by ants (Hymenoptera: Formicidae) in a public hospital in North-Eastern Brazil.

    PubMed

    Aquino, R S S; Silveira, S S; Pessoa, W F B; Rodrigues, A; Andrioli, J L; Delabie, J H C; Fontana, R

    2013-03-01

    The increase in opportunistic fungal infections has led to the search for putative sources of contamination in hospital environments. Ants in a public hospital in Itabuna, north-eastern Brazil were examined for carriage of filamentous fungi. During a year-long survey, ants from different hospital areas were sampled. Preference was given to locations where it was possible to observe ants actively foraging. The fungi found on the ants' integument were cultured and identified. A total of 106 ant workers belonging to 12 species in 11 genera were collected. A total of 47 fungal strains was isolated from 40% of the ants (N = 42). We found 16 fungal species in 13 genera associated with the ant workers. The prevalent fungal genera were Aspergillus, Purpureocillium and Fusarium. The ants Tapinoma melanocephalum, Paratrechina longicornis and Pheidole megacephala were associated with six fungal genera; and four genera of fungi were associated with Solenopsis saevissima workers. Fungal diversity was higher in the following hospital areas: nursery, hospital beds, breastmilk bank and paediatrics. Ants act as carriers of soil and airborne fungal species, and ant control in hospital areas is necessary to prevent the dissemination of such micro-organisms. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  1. Ant plant herbivore interactions in the neotropical cerrado savanna

    NASA Astrophysics Data System (ADS)

    Oliveira, Paulo S.; Freitas, André V. L.

    2004-12-01

    The Brazilian cerrado savanna covers nearly 2 million km2 and has a high incidence on foliage of various liquid food sources such as extrafloral nectar and insect exudates. These liquid rewards generate intense ant activity on cerrado foliage, making ant plant herbivore interactions especially prevalent in this biome. We present data on the distribution and abundance of extrafloral nectaries in the woody flora of cerrado communities and in the flora of other habitats worldwide, and stress the relevance of liquid food sources (including hemipteran honeydew) for the ant fauna. Consumption by ants of plant and insect exudates significantly affects the activity of the associated herbivores of cerrado plant species, with varying impacts on the reproductive output of the plants. Experiments with an ant plant butterfly system unequivocally demonstrate that the behavior of both immature and adult lepidopterans is closely related to the use of a risky host plant, where intensive visitation by ants can have a severe impact on caterpillar survival. We discuss recent evidence suggesting that the occurrence of liquid rewards on leaves plays a key role in mediating the foraging ecology of foliage-dwelling ants, and that facultative ant plant mutualisms are important in structuring the community of canopy arthropods. Ant-mediated effects on cerrado herbivore communities can be revealed by experiments performed on wide spatial scales, including many environmental factors such as soil fertility and vegetation structure. We also present some research questions that could be rewarding to investigate in this major neotropical savanna.

  2. Ant Homing Ability Is Not Diminished When Traveling Backwards

    PubMed Central

    Ardin, Paul B.; Mangan, Michael; Webb, Barbara

    2016-01-01

    Ants are known to be capable of homing to their nest after displacement to a novel location. This is widely assumed to involve some form of retinotopic matching between their current view and previously experienced views. One simple algorithm proposed to explain this behavior is continuous retinotopic alignment, in which the ant constantly adjusts its heading by rotating to minimize the pixel-wise difference of its current view from all views stored while facing the nest. However, ants with large prey items will often drag them home while facing backwards. We tested whether displaced ants (Myrmecia croslandi) dragging prey could still home despite experiencing an inverted view of their surroundings under these conditions. Ants moving backwards with food took similarly direct paths to the nest as ants moving forward without food, demonstrating that continuous retinotopic alignment is not a critical component of homing. It is possible that ants use initial or intermittent retinotopic alignment, coupled with some other direction stabilizing cue that they can utilize when moving backward. However, though most ants dragging prey would occasionally look toward the nest, we observed that their heading direction was not noticeably improved afterwards. We assume ants must use comparison of current and stored images for corrections of their path, but suggest they are either able to chose the appropriate visual memory for comparison using an additional mechanism; or can make such comparisons without retinotopic alignment. PMID:27147991

  3. Toxicity and sublethal effects of sulfoxaflor on the red imported fire ant, Solenopsis invicta.

    PubMed

    Pan, Fengxiang; Lu, Yongyue; Wang, Lei

    2017-05-01

    To understand whether sulfoxaflor, a novel neonicotinoid, poses unacceptable risks to the environment, it is important to assess its effects on nontarget insects. Therefore, the effects of short-term exposure (28 days) of free-feeding sublethal concentrations (1-2μg/ml) of sulfoxaflor to the red imported fire ant, Solenopsis invicta, were investigated. The following parameters were evaluated to determine the impact of exposure: colony growth, food consumption (sugar water and locusts), and interspecific interactions. Sulfoxaflor exposure produced significant negative effects on S. invicta colony growth, with cumulative colony weight losses of 83.36% and 100.00% after treatment with 1μg/ml and 2μg/ml, respectively. The consumption of sugar water (containing sulfoxaflor) of surviving colonies decreased with increasing sulfoxaflor concentration. Moreover, the consumption of locusts decreased after treatment with 2μg/ml, but not 1μg/ml, sulfoxaflor. Sulfoxaflor treatment for 14 days led to reduced aggressiveness of S. invicta workers in interspecific confrontations (S. invicta vs. unexposed Pheidole fervida), and their probability of survival of aggressive encounters was reduced significantly to 48% of that of control ants. Our results indicate that sublethal concentrations of sulfoxaflor are likely to have a negative impact on ants.

  4. Microfungal "weeds" in the leafcutter ant symbiosis.

    PubMed

    Rodrigues, A; Bacci, M; Mueller, U G; Ortiz, A; Pagnocca, F C

    2008-11-01

    Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis.

  5. Egg-laying butterflies distinguish predaceous ants by sight.

    PubMed

    Sendoya, Sebastián F; Freitas, André V L; Oliveira, Paulo S

    2009-07-01

    Information about predation risks is critical for herbivorous insects, and natural selection favors their ability to detect predators before oviposition and to select enemy-free foliage when offspring mortality risk is high. Food plants are selected by ovipositing butterflies, and offspring survival frequently varies among plants because of variation in the presence of predators. Eunica bechina butterflies oviposit on Caryocar brasiliense, an ant-defended plant. Experiments with dried Camponotus and Cephalotes ants pinned to leaves revealed that butterflies use ant size and form as visual cues to avoid ovipositing on plant parts occupied by ants more likely to kill larval offspring. Presence of sap-sucking bugs did not affect butterfly oviposition. This is the first demonstration that visual recognition of predators can mediate egg-laying decisions by an insect herbivore and that an insect will discriminate among different species of potential predators. This unusual behavioral capability permits specialization on a risky, ant-defended food plant.

  6. Plant-derived differences in the composition of aphid honeydew and their effects on colonies of aphid-tending ants.

    PubMed

    Pringle, Elizabeth G; Novo, Alexandria; Ableson, Ian; Barbehenn, Raymond V; Vannette, Rachel L

    2014-11-01

    In plant-ant-hemipteran interactions, ants visit plants to consume the honeydew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects change ant behavior, they could feed back to affect the plant itself. We compared the chemical composition of honeydews produced by Aphis nerii aphid clones on two milkweed congeners, Asclepias curassavica and Asclepias incarnata, and we measured the responses of experimental Linepithema humile ant colonies to these honeydews. The compositions of secondary metabolites, sugars, and amino acids differed significantly in the honeydews from the two plant species. Ant colonies feeding on honeydew derived from A. incarnata recruited in higher numbers to artificial diet, maintained higher queen and worker dry weight, and sustained marginally more workers than ants feeding on honeydew derived from A. curassavica. Ants feeding on honeydew from A. incarnata were also more exploratory in behavioral assays than ants feeding from A. curassavica. Despite performing better when feeding on the A. incarnata honeydew, ant workers marginally preferred honeydew from A. curassavica to honeydew from A. incarnata when given a choice. Our results demonstrate that plant congeners can exert strong indirect effects on ant colonies by means of plant-species-specific differences in aphid honeydew chemistry. Moreover, these effects changed ant behavior and thus could feed back to affect plant performance in the field.

  7. A cuckoo-like parasitic moth leads African weaver ant colonies to their ruin.

    PubMed

    Dejean, Alain; Orivel, Jérôme; Azémar, Frédéric; Hérault, Bruno; Corbara, Bruno

    2016-03-29

    In myrmecophilous Lepidoptera, mostly lycaenids and riodinids, caterpillars trick ants into transporting them to the ant nest where they feed on the brood or, in the more derived "cuckoo strategy", trigger regurgitations (trophallaxis) from the ants and obtain trophic eggs. We show for the first time that the caterpillars of a moth (Eublemma albifascia; Noctuidae; Acontiinae) also use this strategy to obtain regurgitations and trophic eggs from ants (Oecophylla longinoda). Females short-circuit the adoption process by laying eggs directly on the ant nests, and workers carry just-hatched caterpillars inside. Parasitized colonies sheltered 44 to 359 caterpillars, each receiving more trophallaxis and trophic eggs than control queens. The thus-starved queens lose weight, stop laying eggs (which transport the pheromones that induce infertility in the workers) and die. Consequently, the workers lay male-destined eggs before and after the queen's death, allowing the colony to invest its remaining resources in male production before it vanishes.

  8. Foraging of Psilocybe basidiocarps by the leaf-cutting ant Acromyrmex lobicornis in Santa Fé, Argentina.

    PubMed

    Masiulionis, Virginia E; Weber, Roland Ws; Pagnocca, Fernando C

    2013-12-01

    It is generally accepted that material collected by leaf-cutting ants of the genus Acromyrmex consists solely of plant matter, which is used in the nest as substrate for a symbiotic fungus providing nutrition to the ants. There is only one previous report of any leaf-cutting ant foraging directly on fungal basidiocarps. Basidiocarps of Psilocybe coprophila growing on cow dung were actively collected by workers of Acromyrmex lobicornis in Santa Fé province, Argentina. During this behaviour the ants displayed typical signals of recognition and continuously recruited other foragers to the task. Basidiocarps of different stages of maturity were being transported into the nest by particular groups of workers, while other workers collected plant material. The collection of mature basidiocarps with viable spores by leaf-cutting ants in nature adds substance to theories relating to the origin of fungiculture in these highly specialized social insects.

  9. A model for collective dynamics in ant raids.

    PubMed

    Ryan, Shawn D

    2016-05-01

    Ant raiding, the process of identifying and returning food to the nest or bivouac, is a fascinating example of collective motion in nature. During such raids ants lay pheromones to form trails for others to find a food source. In this work a coupled PDE/ODE model is introduced to study ant dynamics and pheromone concentration. The key idea is the introduction of two forms of ant dynamics: foraging and returning, each governed by different environmental and social cues. The model accounts for all aspects of the raiding cycle including local collisional interactions, the laying of pheromone along a trail, and the transition from one class of ants to another. Through analysis of an order parameter measuring the orientational order in the system, the model shows self-organization into a collective state consisting of lanes of ants moving in opposite directions as well as the transition back to the individual state once the food source is depleted matching prior experimental results. This indicates that in the absence of direct communication ants naturally form an efficient method for transporting food to the nest/bivouac. The model exhibits a continuous kinetic phase transition in the order parameter as a function of certain system parameters. The associated critical exponents are found, shedding light on the behavior of the system near the transition.

  10. Experience influences aggressive behaviour in the Argentine ant

    PubMed Central

    Van Wilgenburg, Ellen; Clémencet, Johanna; Tsutsui, Neil D.

    2010-01-01

    All animals interact with conspecifics during their life, and nearly all also display some form of aggression. An enduring challenge, however, is to understand how the experiences of an individual animal influence its later behaviours. Several studies have shown that prior winning experience increases the probability of initiating fights in later encounters. Using behavioural assays in the laboratory, we provide evidence that, in Argentine ants (Linepithema humile), the mere exposure to an opponent, without the encounter escalating to a fight, also increases the probability that it will display aggression in later encounters. Argentine ant workers differ in their propensity to attack non-colonymates, with some ants repeatedly aggressive and others consistently more docile. Although 78 per cent of the workers were consistent in their behaviour from one encounter to the next, workers that did change their behaviour after an encounter with a non-colonymate more often changed from non-aggressive to aggressive, rather than the reverse. Surprisingly, a single encounter with a non-colonymate increased a worker's propensity to fight in encounters up to a week later. An encounter with a non-colonymate also increased the probability that a worker would attack ants from a colony that it had not previously encountered. Thus, these interactions lowered the overall aggression threshold, rather than stimulating a specific aggressive response to a particular foreign colony. Finally, our data suggest that aggression towards non-colonymates increases with age. PMID:19793741

  11. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029065 (12 Jan. 2014) --- In the International Space Station's Destiny laboratory, NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  12. Ants in Space

    NASA Image and Video Library

    2014-01-13

    ISS038-E-029133 (12 Jan. 2014) --- The Ant Forage Habitat Facility is featured in this image photographed by an Expedition 38 crew member on the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  13. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029059 (12 Jan. 2014) --- In the International Space Station's Destiny laboratory, NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  14. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029077 (12 Jan. 2014) --- In the International Space Station's Harmony node, NASA astronaut Mike Hopkins, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  15. Ants in Space

    NASA Image and Video Library

    2014-01-13

    ISS038-E-029106 (12 Jan. 2014) --- The Ant Forage Habitat Facility is featured in this image photographed by an Expedition 38 crew member on the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  16. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029062 (12 Jan. 2014) --- In the International Space Station's Destiny laboratory, NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  17. Ants in Space

    NASA Image and Video Library

    2014-01-14

    ISS038-E-029161 (12 Jan. 2014) --- The Ant Forage Habitat Facility is featured in this image photographed by an Expedition 38 crew member on the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  18. Evolution of a soldier caste specialized to lay unfertilized eggs in the ant genus Crematogaster (subgenus Orthocrema).

    PubMed

    Peeters, Christian; Lin, Chung-Chi; Quinet, Yves; Martins Segundo, Glauco; Billen, Johan

    2013-05-01

    Among social Hymenoptera, only some ant genera have more than one morphological kind of non-reproductive adults. Individuals that are bigger than ordinary workers can function for defence and/or food storage. In Crematogaster (Orthocrema) smithi from Arizona, a third caste exists in addition to winged queens and workers; it is intermediate in size, weight and morphology, and individuals lay many unfertilized eggs that are mostly eaten by larvae (Heinze et al., 1995, 1999). We studied another three species belonging to the subgenus Orthocrema: Crematogaster pygmaea from Brazil, Crematogaster biroi and Crematogaster schimmeri from Taiwan. Using scanning electron microscopy and ovarian dissections, we show that 'intermediates' are a patchwork of queen-like and worker-like traits, just as in C. smithi; importantly the combinations differ across species. 'Intermediates' are numerically few in the colonies, and in C. pygmaea they are produced seasonally. Using histology we confirmed the lack of a spermatheca, thus they are not ergatoid queens. Based on the similarity of their mosaic phenotypes with those in other ant lineages, we suggest that Orthocrema 'intermediates' are a soldier caste with a specialized trophic function. This soldier caste has been reported in other Orthocrema species from Madagascar, Guinea and Costa Rica, suggesting that it is widespread in this subgenus.

  19. Foraging leaf-cutting ants learn to reject Vitis vinifera ssp. vinifera plants that emit herbivore-induced volatiles.

    PubMed

    Thiele, Theresa; Kost, Christian; Roces, Flavio; Wirth, Rainer

    2014-06-01

    Leaf-cutting ants (LCAs) are dominant herbivores of the Neotropics, as well as economically important pests. Their foraging ecology and patterns/mechanisms of food selection have received considerable attention. Recently, it has been documented that LCAs exhibit a delayed rejection of previously accepted food plants following treatment with a fungicide that makes the plants unsuitable as substrate for their symbiotic fungus. Here, we investigated whether LCAs similarly reject plants with induced chemical defenses, by combining analysis of volatile emissions with dual-choice bioassays that used LCA subcolonies (Atta sexdens L.). On seven consecutive days, foraging ants were given the choice between leaf disks from untreated control plants and test plants of Vitis vinifera ssp. vinifera L. treated with the phytohormone jasmonic acid (JA) to mimic herbivore attack. Chemical analysis revealed the emission of a characteristic set of herbivore-induced volatile organic compounds (VOC) from JA-induced plants. Dual-choice experiments indicated that workers did not show any preference initially, but that they avoided JA-treated plants from day five onwards. Our finding that A. sexdens foragers learn to avoid VOC-emitting plants, which are likely detrimental to their symbiotic fungus, represents the first evidence for avoidance learning in attine ants toward plants with induced defenses.

  20. Can the Argentine ant ( Linepithema humile Mayr) replace native ants in myrmecochory?

    NASA Astrophysics Data System (ADS)

    Gómez, Crisanto; Oliveras, Jordi

    2003-04-01

    We analyse the influence of the Argentine ant ( Linepithema humile Mayr) on the seed dispersal process of the myrmecochorous plants Euphorbia characias, E. biumbellata, Genista linifolia, G. triflora, G. monspessulana and Sarothamnus arboreus. The observations were made in two study plots of Mediterranean cork-oak secondary forest (invaded and non-invaded by L. humile). The presence of L. humile implies the displacement of all native ant species that disperse seeds. Seed transports in the non-invaded zone were carried out by eight ant species. In the invaded zone, L. humile workers removed and transported seeds to the nest. In vertebrate exclusion trials, we observed the same level of seed removal in the invaded and non-invaded zones. Two findings could explain this result. Although mean time to seed localization was higher for native ants (431.7 s) than that for L. humile (150.5 s), the mean proportion of seeds transported after being detected was higher (50.1%) in non-invaded than in invaded (16.8%) zones. The proportion of seeds removed and transported into an ant nest after an ant-seed interaction had dramatically reduced from non-invaded (41.9%) to invaded (7.4%) zones. The levels of seed dispersal by ants found prior to invasion are unlikely to be maintained in invaded zones. However, total replacement of seed dispersal function is possible if contact iteration finally offers similar levels or quantities of seeds reaching the nests. The results obtained confirm that the Argentine ant invasion may affect myrmecochory dramatically in the Mediterranean biome.

  1. Spectacular Batesian mimicry in ants.

    PubMed

    Ito, Fuminori; Hashim, Rosli; Huei, Yek Sze; Kaufmann, Eva; Akino, Toshiharu; Billen, Johan

    2004-10-01

    The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.

  2. Spectacular Batesian mimicry in ants

    NASA Astrophysics Data System (ADS)

    Ito, Fuminori; Hashim, Rosli; Huei, Yek Sze; Kaufmann, Eva; Akino, Toshiharu; Billen, Johan

    2004-10-01

    The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.

  3. The effect of disturbance on an ant-plant mutualism.

    PubMed

    Piovia-Scott, Jonah

    2011-06-01

    Protective ant-plant mutualisms-where plants provide food or shelter to ants and ants protect the plants from herbivores-are a common feature in many ecological communities, but few studies have examined the effect of disturbance on these interactions. Disturbance may affect the relationship between plants and their associated ant mutualists by increasing the plants' susceptibility to herbivores, changing the amount of reward provided for the ants, and altering the abundance of ants and other predators. Pruning was used to simulate the damage to buttonwood mangrove (Conocarpus erectus) caused by hurricanes. Pruned plants grew faster than unpruned plants, produced lower levels of physical anti-herbivore defenses (trichomes, toughness), and higher levels of chemical defenses (tannins) and extrafloral nectaries. Thus, simulated hurricane damage increased plant growth and the amount of reward provided to ant mutualists, but did not have consistent effects on other anti-herbivore defenses. Both herbivores and ants increased in abundance on pruned plants, indicating that the effects of simulated hurricane damage on plant traits were propagated to higher trophic levels. Ant-exclusion led to higher leaf damage on both pruned and upruned plants. The effect of ant-exclusion did not differ between pruned and unpruned plants, despite the fact that pruned plants had higher ant and herbivore densities, produced more extrafloral nectaries, and had fewer physical defenses. Another common predator, clubionid spiders, increased in abundance on pruned plants from which ants had been excluded. I suggest that compensatory predation by these spiders diminished the effect of ant-exclusion on pruned plants.

  4. [Coexistence mechanism of ant community in lac plantation under habitat heterogeneity].

    PubMed

    Wang, Si-ming; Chen, You-qing; Lu, Zhi-xing; Liu, Chun-ju; Guo, Zu-xue

    2010-10-01

    In order to reveal the coexistence mechanism of ant community in lac plantation, an investigation was made on the ant community composition and the ability of ant species in discovering and holding food resources in a lac plantation in Yayi Town of Mojiang County, Yunnan Province, with the relationships between ant body size and its ability of finding food under habitat heterogeneity probed. There were six dominant ant species in the plantation, i. e., Tetraponera allaborans (Walker), Crematogaster macaoensis Wheeler, Crematogasterferrarii Emery, Dolichoderus thoracicus (Smith), Polyrhachis proxima Roger, and Camponotus parius Emery. The hind leg length (y) of the six ant species increased allometrically with their head width (x), and the regression equation was y = 0.56 + 1.02x + 5.97x2 - 10.85x3. Different ant species had significant differences in their actual and relative frequency in discovering food resources in different habitats, but habitat type had no significant effects on the actual frequency in holding food resources by the ant species. The ant species with bigger head width and bigger body size index could discover more food resources in simple habitat. In contrast, the ant species with smaller head width, shorter hind leg length, and smaller body size index could discover more food resources in complex habitat. The heterogeneity of habitat caused the coexistence of ants: the smaller ant species lived in complex habitat, while the larger ones lived in simple habitat. In addition, numerically dominant ant species were unable to possess all resources, and thereby, could provide the opportunity to other ant species for resources acquisition, making the species coexistence come true.

  5. Clonal reproduction with androgenesis and somatic recombination: the case of the ant Cardiocondyla kagutsuchi

    NASA Astrophysics Data System (ADS)

    Okita, Ichiro; Tsuchida, Koji

    2016-04-01

    In haplodiploid insects such as ants, male sexuals develop from unfertilised haploid eggs, while female sexuals and workers develop from fertilized diploid eggs. However, some ant species do not exchange their gene pool between sexes; both male and female sexuals are clonally produced, while workers are sexually produced. To date, three ant species, Wasmannia auropunctata, Vollenhovia emeryi, and Paratrechina longicornis, have been reported to reproduce using such reproductive systems. In this study, we reveal that in one lineage of the ant Cardiocondyla kagutsuchi, male and female sexuals are also clonally produced. In contrast to the abovementioned three species, the workers were not only sexually produced but had recombinant sequences in their nuclear internal transcribed spacer regions, although the recombinant sequences were not detected in male or female sexuals. These results suggest that the lineage likely possesses a mechanism to compensate for the reduction in genetic variation due to clonal reproduction with somatic recombination that occurs within the workers.

  6. Clonal reproduction with androgenesis and somatic recombination: the case of the ant Cardiocondyla kagutsuchi.

    PubMed

    Okita, Ichiro; Tsuchida, Koji

    2016-04-01

    In haplodiploid insects such as ants, male sexuals develop from unfertilised haploid eggs, while female sexuals and workers develop from fertilized diploid eggs. However, some ant species do not exchange their gene pool between sexes; both male and female sexuals are clonally produced, while workers are sexually produced. To date, three ant species, Wasmannia auropunctata, Vollenhovia emeryi, and Paratrechina longicornis, have been reported to reproduce using such reproductive systems. In this study, we reveal that in one lineage of the ant Cardiocondyla kagutsuchi, male and female sexuals are also clonally produced. In contrast to the abovementioned three species, the workers were not only sexually produced but had recombinant sequences in their nuclear internal transcribed spacer regions, although the recombinant sequences were not detected in male or female sexuals. These results suggest that the lineage likely possesses a mechanism to compensate for the reduction in genetic variation due to clonal reproduction with somatic recombination that occurs within the workers.

  7. Opposable spines facilitate fine and gross object manipulation in fire ants.

    PubMed

    Cassill, Deby; Greco, Anthony; Silwal, Rajesh; Wang, Xuefeng

    2007-04-01

    Ants inhabit diverse terrestrial biomes from the Sahara Desert to the Arctic tundra. One factor contributing to the ants' successful colonization of diverse geographical regions is their ability to manipulate objects when excavating nests, capturing, transporting and rendering prey or grooming, feeding and transporting helpless brood. This paper is the first to report the form and function of opposable spines on the foretarsi of queens and workers used during fine motor and gross motor object manipulation in the fire ant, Solenopsis invicta. In conjunction with their mandibles, queens and workers used their foretarsi to grasp and rotate eggs, push or pull thread-like objects out of their way or push excavated soil pellets behind them for disposal by other workers. Opposable spines were found on the foretarsi of workers from seven of eight other ant species suggesting that they might be a common feature in the Formicidae.

  8. Ant Colonies Do Not Trade-Off Reproduction against Maintenance.

    PubMed

    Kramer, Boris H; Schrempf, Alexandra; Scheuerlein, Alexander; Heinze, Jürgen

    2015-01-01

    The question on how individuals allocate resources into maintenance and reproduction is one of the central questions in life history theory. Yet, resource allocation into maintenance on the organismic level can only be measured indirectly. This is different in a social insect colony, a "superorganism" where workers represent the soma and the queen the germ line of the colony. Here, we investigate whether trade-offs exist between maintenance and reproduction on two levels of biological organization, queens and colonies, by following single-queen colonies of the ant Cardiocondyla obscurior throughout the entire lifespan of the queen. Our results show that maintenance and reproduction are positively correlated on the colony level, and we confirm results of an earlier study that found no trade-off on the individual (queen) level. We attribute this unexpected outcome to the existence of a positive feedback loop where investment into maintenance (workers) increases the rate of resource acquisition under laboratory conditions. Even though food was provided ad libitum, variation in productivity among the colonies suggests that resources can only be utilized and invested into additional maintenance and reproduction by the colony if enough workers are available. The resulting relationship between per-capita and colony productivity in our study fits well with other studies conducted in the field, where decreasing per-capita productivity and the leveling off of colony productivity have been linked to density dependent effects due to competition among colonies. This suggests that the absence of trade-offs in our laboratory study might also be prevalent under natural conditions, leading to a positive association of maintenance, (= growth) and reproduction. In this respect, insect colonies resemble indeterminate growing organisms.

  9. Colony-level impacts of parasitoid flies on fire ants.

    PubMed Central

    Mehdiabadi, Natasha J; Gilbert, Lawrence E

    2002-01-01

    The red imported fire ant is becoming a global ecological problem, having invaded the United States, Puerto Rico, New Zealand and, most recently, Australia. In its established areas, this pest is devastating natural biodiversity. Early attempts to halt fire ant expansion with pesticides actually enhanced its spread. Phorid fly parasitoids from South America have now been introduced into the United States as potential biological control agents of the red imported fire ant, but the impact of these flies on fire ant populations is currently unknown. In the laboratory, we show that an average phorid density of as little as one attacking fly per 200 foraging ants decreased colony protein consumption nearly twofold and significantly reduced numbers of large-sized workers 50 days later. The high impact of a single phorid occurred mainly because ants decreased foraging rates in the presence of the flies. Our experiments, the first (to our knowledge) to link indirect and direct effects of phorids on fire ants, demonstrate that colonies can be stressed with surprisingly low parasitoid densities. We interpret our findings with regard to the more complex fire ant-phorid interactions in the field. PMID:12204130

  10. A castration parasite of an ant-plant mutualism

    PubMed Central

    Yu, D. W.; Pierce, N. E.

    1998-01-01

    Exploring the factors governing the maintenance and breakdown of cooperation between mutualists is an intriguing and enduring problem for evolutionary ecology, and symbioses between ants and plants can provide useful experimental models for such studies. Hundreds of tropical plant species have evolved structures to house and feed ants, and these ant–plant symbioses have long been considered classic examples of mutualism. Here, we report that the primary ant symbiont, Allomerus cf. demerarae, of the most abundant ant-plant found in south-east Peru, Cordia nodosa Lam., castrates its host plant. Allomerus workers protect new leaves and their associated domatia from herbivory, but destroy flowers, reducing fruit production to zero in most host plants. Castrated plants occupied by Allomerus provide more domatia for their associated ants than plants occupied by three species of Azteca ants that do not castrate their hosts. Allomerus colonies in larger plants have higher fecundity. As a consequence, Allomerus appears to benefit from its castration behaviour, to the detriment of C. nodosa. The C. nodosa–ant system exhibits none of the retaliatory or filtering mechanisms shown to stabilize cheating in other cooperative systems, and appears to persist because some of the plants, albeit a small minority, are inhabited by the three species of truly mutualistic Azteca ants.

  11. Release and establishment of the little decapitating fly Pseudacteon cultellatus on imported fire ants in Florida

    USDA-ARS?s Scientific Manuscript database

    The little decapitating fly Pseudacteon cultellatus from Argentina was released as a self-sustaining biological control agent against the red imported fire ant, Solenopsis invicta, in Florida to parasitize small fire ant workers associated with multiple-queen colonies. This fly appears to be establi...

  12. Multilocus genetic characterization of two ant vectors (Group II ‘‘Dirty 22’’ species) known to contaminate food and food products and spread foodborne pathogens

    USDA-ARS?s Scientific Manuscript database

    The U.S. Food and Drug Administration utilizes the presence of filth and extraneous materials as one of the criteria for implementing regulatory actions and assessing adulteration of food products of public health importance. Twenty-two prevalent pest species (also known as the ‘‘Dirty 22’’ species)...

  13. Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 9. Washing and drying of hands to reduce microbial contamination.

    PubMed

    Todd, Ewen C D; Michaels, Barry S; Smith, Debra; Greig, Judy D; Bartleson, Charles A

    2010-10-01

    During various daily activities at home and work, hands quickly become contaminated. Some activities increase the risk of finger contamination by pathogens more than others, such as the use of toilet paper to clean up following a diarrheal episode, changing the diaper of a sick infant, blowing a nose, or touching raw food materials. Many foodborne outbreak investigation reports have identified the hands of food workers as the source of pathogens in the implicated food. The most convenient and efficient way of removing pathogens from hands is through hand washing. Important components of hand washing are potable water for rinsing and soaps to loosen microbes from the skin. Hand washing should occur after any activity that soils hands and certainly before preparing, serving, or eating food. Antimicrobial soaps are marginally more effective than plain soaps, but constant use results in a buildup of the antimicrobial compound on the skin. The time taken to wash hands and the degree of friction generated during lathering are more important than water temperature for removing soil and microorganisms. However, excessive washing and scrubbing can cause skin damage and infections. Drying hands with a towel removes pathogens first by friction during rubbing with the drying material and then by wicking away the moisture into that material. Paper rather than cloth towels should be encouraged, although single-use cloth towels are present in the washrooms of higher class hotels and restaurants. Warm air dryers remove moisture and any surface microorganisms loosened by washing from hands by evaporation while the hands are rubbed together vigorously; however, these dryers take too long for efficient use. The newer dryers with high-speed air blades can achieve dryness in 10 to 15 s without hand rubbing.

  14. Implications of stridulation behavior in the red and black imported fire ants, Solenopsis invicta Buren and Solenopsis richteri Forel, and their hybrid

    NASA Astrophysics Data System (ADS)

    Marquess, Jake

    Stridulation elicits a variety of behavioral responses in the Formicidae: distress, alarm and recruitment of nestmates. The intent of my research is to broaden the understanding of stridulation by investigating the morphology, multiple behaviors in which stridulation has been observed, and the behavioral response to the playback of these stridulatory signals in two closely related species, Solenopsis invicta, S. richteri, and their hybrid. A SEM examination of head width and the stridulatory organs of imported fire ant workers found the number of ridges on the "file" ( pars striden) to be positively correlated with body size. The increase in ridge number in relation to body size suggests that the number of pulses in each pulse train of the stridulation signal should increase as body size increases. Stridulation was not correlated with excavation behavior, but grinding, an incidental sound resulting from soil excavation, is a reliable indicator of excavation behavior. Absence of stridulation upon initial discovery of the food source and low amount of stridulation observed with ten or less ants present at the food source indicates that stridulation does not serve as an initial short range recruitment signal to nearby nestmates. Furthermore, over 90% of the total stridulation observed was recorded with 30 or more ants present at the food source. Finally, the time between calls decreased and the number of stridulations increased as more ants arrived at the food source. Stridulation in dyadic encounters between ants occurs almost exclusively during non-nestmate conspecitic interactions. Restrained ants or "defenders" accounted for 92.9% of the total stridulation observed compared to just 3.4% for "attackers." Restraint between the head and thorax or "neck" evoked the highest level of stridulation in majors. Stridulation during non-nestmate interactions is size specific, as trials involving majors had nearly twice as much stridulation (88.3%), than trials with mediums

  15. Desert ants achieve reliable recruitment across noisy interactions.

    PubMed

    Razin, Nitzan; Eckmann, Jean-Pierre; Feinerman, Ofer

    2013-05-06

    We study how desert ants, Cataglyphis niger, a species that lacks pheromone-based recruitment mechanisms, inform each other about the presence of food. Our results are based on automated tracking that allows us to collect a large database of ant trajectories and interactions. We find that interactions affect an ant's speed within the nest. Fast ants tend to slow down, whereas slow ones increase their speed when encountering a faster ant. Faster ants tend to exit the nest more frequently than slower ones. So, if an ant gains enough speed through encounters with others, then she tends to leave the nest and look for food. On the other hand, we find that the probability for her to leave the nest depends only on her speed, but not on whether she had recently interacted with a recruiter that has found the food. This suggests a recruitment system in which ants communicate their state by very simple interactions. Based on this assumption, we estimate the information-theoretical channel capacity of the ants' pairwise interactions. We find that the response to the speed of an interacting nest-mate is very noisy. The question is then how random interactions with ants within the nest can be distinguished from those interactions with a recruiter who has found food. Our measurements and model suggest that this distinction does not depend on reliable communication but on behavioural differences between ants that have found the food and those that have not. Recruiters retain high speeds throughout the experiment, regardless of the ants they interact with; non-recruiters communicate with a limited number of nest-mates and adjust their speed following these interactions. These simple rules lead to the formation of a bistable switch on the level of the group that allows the distinction between recruitment and random noise in the nest. A consequence of the mechanism we propose is a negative effect of ant density on exit rates and recruitment success. This is, indeed, confirmed by our

  16. Social coercion of larval development in an ant species

    NASA Astrophysics Data System (ADS)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  17. The cavity-nest ant Temnothorax crassispinus prefers larger nests.

    PubMed

    Mitrus, S

    Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm(3), respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm(3) nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

  18. Plant-derived differences in the composition of aphid honeydew and their effects on colonies of aphid-tending ants

    PubMed Central

    Pringle, Elizabeth G; Novo, Alexandria; Ableson, Ian; Barbehenn, Raymond V; Vannette, Rachel L

    2014-01-01

    In plant–ant–hemipteran interactions, ants visit plants to consume the honeydew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects change ant behavior, they could feed back to affect the plant itself. We compared the chemical composition of honeydews produced by Aphis nerii aphid clones on two milkweed congeners, Asclepias curassavica and Asclepias incarnata, and we measured the responses of experimental Linepithema humile ant colonies to these honeydews. The compositions of secondary metabolites, sugars, and amino acids differed significantly in the honeydews from the two plant species. Ant colonies feeding on honeydew derived from A. incarnata recruited in higher numbers to artificial diet, maintained higher queen and worker dry weight, and sustained marginally more workers than ants feeding on honeydew derived from A. curassavica. Ants feeding on honeydew from A. incarnata were also more exploratory in behavioral assays than ants feeding from A. curassavica. Despite performing better when feeding on the A. incarnata honeydew, ant workers marginally preferred honeydew from A. curassavica to honeydew from A. incarnata when given a choice. Our results demonstrate that plant congeners can exert strong indirect effects on ant colonies by means of plant-species-specific differences in aphid honeydew chemistry. Moreover, these effects changed ant behavior and thus could feed back to affect plant performance in the field. PMID:25505534

  19. By their own devices: invasive Argentine ants have shifted diet without clear aid from symbiotic microbes.

    PubMed

    Hu, Yi; Holway, David A; Łukasik, Piotr; Chau, Linh; Kay, Adam D; LeBrun, Edward G; Miller, Katie A; Sanders, Jon G; Suarez, Andrew V; Russell, Jacob A

    2017-03-01

    The functions and compositions of symbiotic bacterial communities often correlate with host ecology. Yet cause-effect relationships and the order of symbiont vs. host change remain unclear in the face of ancient symbioses and conserved host ecology. Several groups of ants exemplify this challenge, as their low-nitrogen diets and specialized symbioses appear conserved and ancient. To address whether nitrogen-provisioning symbionts might be important in the early stages of ant trophic shifts, we studied bacteria from the Argentine ant, Linepithema humile - an invasive species that has transitioned towards greater consumption of sugar-rich, nitrogen-poor foods in parts of its introduced range. Bacteria were present at low densities in most L. humile workers, and among those yielding quality 16S rRNA amplicon sequencing data, we found just three symbionts to be common and dominant. Two, a Lactobacillus and an Acetobacteraceae species, were shared between native and introduced populations. The other, a Rickettsia, was found only in two introduced supercolonies. Across an eight-year period of trophic reduction in one introduced population, we found no change in symbionts, arguing against a relationship between natural dietary change and microbiome composition. Overall, our findings thus argue against major changes in symbiotic bacteria in association with the invasion and trophic shift of L. humile. In addition, genome content from close relatives of the identified symbionts suggests that just one can synthesize most essential amino acids; this bacterium was only modestly abundant in introduced populations, providing little support for a major role of nitrogen-provisioning symbioses in Argentine ant's dietary shift.

  20. Field techniques for sampling ants

    USDA-ARS?s Scientific Manuscript database

    Ants occur in most environments and ecologists ask a diverse array of questions involving ants