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Sample records for ig prey females

  1. Size-biased allocation of prey from male to offspring via female: family conflicts, prey selection, and evolution of sexual size dimorphism in raptors.

    PubMed

    Sonerud, Geir A; Steen, Ronny; Løw, Line M; Røed, Line T; Skar, Kristin; Selås, Vidar; Slagsvold, Tore

    2013-05-01

    In birds with bi-parental care, the provisioning link between prey capture and delivery to dependent offspring is regarded as often symmetric between the mates. However, in raptors, the larger female usually broods and feeds the nestlings, while the smaller male provides food for the family, assisted by the female in the latter part of the nestling period, if at all. Prey items are relatively large and often impossible for nestlings to handle without extended maternal assistance. We video-recorded prey delivery and handling in nests of a raptor with a wide diet, the Eurasian kestrel Falco tinnunculus, and simultaneously observed prey transfer from male to female outside the nest. The male selectively allocated larger items, in particular birds and larger mammals, to the female for further processing and feeding of nestlings, and smaller items, in particular lizards and smaller mammals, directly to the nestlings for unassisted feeding. Hence, from the video, the female appeared to have captured larger prey than the male, while in reality no difference existed. The female's size-biased interception of the male's prey provisioning line would maximize the male's foraging time, and maximize the female's control of the allocation of food between her own need and that of the offspring. The male would maximize his control of food allocation by capturing smaller prey. This conflict would select for larger dominant females and smaller energy-efficient males, and induce stronger selection the longer the female depends on the male for self-feeding, as a proportion of the offspring dependence period.

  2. Prey resources before spawning influence gonadal investment of female, but not male, white crappie

    USGS Publications Warehouse

    Bunnell, D.B.; Thomas, S.E.; Stein, R.A.

    2007-01-01

    In this study, an outdoor pool experiment was used to evaluate the effect of prey resources during 4 months before spawning on the gonadal investments of male and female white crappie Pomoxis annularis, a popular freshwater sportfish that exhibits erratic recruitment. Fish were assigned one of three feeding treatments: starved, fed once every 5 days (intermediate) or fed daily (high). All measurements of male testes (i.e. wet mass, energy density and spermatocrit) were similar across treatments. Conversely, high-fed females produced larger ovaries than those of intermediate-fed and starved fish, and invested more energy in their ovaries than starved fish. Compared to pre-experiment fish, starved and intermediate-fed females appeared to increase their ovary size by relying on liver energy stores (‘capital’ spawning). Conversely, high-fed females increased liver and gonad mass, implying an ‘income’-spawning strategy (where gonads are built from recently acquired energy). Fecundity did not differ among treatments, but high-fed fish built larger eggs than those starved. Females rarely ‘skipped’ spawning opportunities when prey resources were low, as only 8% of starved females and 8% of intermediate-fed females lacked vitellogenic eggs. These results suggest that limited prey resources during the months before spawning can limit ovary production, which, in turn, can limit reproductive success of white crappies.

  3. Transfer of IgG in the female genital tract by MHC class I-related neonatal Fc receptor (FcRn) confers protective immunity to vaginal infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    IgG is a major immunoglobulin subclass in mucosal secretions of human female genital tract, where it predominates over the IgA isotype. Despite the abundance of IgG, surprisingly little is known about whether and how IgG enters the lumen of the genital tract and the exact role of local IgG may play ...

  4. Serum Uric Acid Level Predicts Progression of IgA Nephropathy in Females but Not in Males

    PubMed Central

    Shoji, Tatsuya; Shinzawa, Maki; Hasuike, Yukiko; Nagatoya, Katsuyuki; Yamauchi, Atsushi; Hayashi, Terumasa; Kuragano, Takayuki; Moriyama, Toshiki; Isaka, Yoshitaka; Nakanishi, Takeshi

    2016-01-01

    Background Immunoglobulin A nephropathy (IgAN) is one of most common forms of glomerulonephritis. At this point, the clinical impact of hyperuricemia on IgAN is not clear. The aim of the present study was to explore the clinical impact of hyperuricemia on the progression of IgAN. Study Design Multicenter retrospective cohort study. Setting & Participants 935 IgAN patients who were diagnosed by kidney biopsy at Osaka University Hospital, Osaka General Hospital, and Osaka Rosai Hospital. were included in this study. Predictor Uric acid levels at renal biopsy. Outcomes The outcome of interest was the time from the kidney biopsy to the time when a 50% increase in the baseline serum creatinine level was observed, which was defined as "progression". Measurements The baseline characteristics according to the kidney biopsy at the time of diagnosis were collected from the medical records, and included age, gender, body mass index, hypertension, diabetes (use of antidiabetic drugs), serum levels of creatinine, urinary protein, smoking status, RAAS blockers and steroid therapy. Results An elevated serum uric acid level was an independent risk factor for progression in female patients (per 1.0 mg/dL, multivariate-adjusted incident rate ratio 1.33 [95% confidence interval 1.07, 1.64], P = 0.008) but not in male patients (1.02 [0.81, 1.29], P = 0.855). To control a confounding effect of renal function on an association between serum uric acid level and progression in female patients, age- and serum creatinine-matched and propensity score-matched analyses were performed, and these results also supported the effect by uric acid on kidney disease progression independent of basal kidney function. Limitations A cohort analyzed retorospectively. Conclusions This study revealed that an elevated uric acid level was an independent risk factor for ESKD in female IgAN patients. Therefore, uric acid might be a treatable target in female IgAN patients. PMID:27560997

  5. New parasitoid-predator associations: female parasitoids do not avoid competition with generalist predators when sharing invasive prey

    NASA Astrophysics Data System (ADS)

    Chailleux, Anaïs; Wajnberg, Eric; Zhou, Yuxiang; Amiens-Desneux, Edwige; Desneux, Nicolas

    2014-12-01

    Optimal habitat selection is essential for species survival in ecosystems, and interspecific competition is a key ecological mechanism for many observed species association patterns. Specialized animal species are commonly affected by resource and interference competition with generalist and/or omnivorous competitors, so avoidance behavior could be expected. We hypothesize that specialist species may exploit broad range cues from such potential resource competitors (i.e., cues possibly common to various generalist and/or omnivorous predators) to avoid costly competition regarding food or reproduction, even in new species associations. We tested this hypothesis by studying short-term interactions between a native larval parasitoid and a native generalist omnivorous predator recently sharing the same invasive host/prey, the leaf miner Tuta absoluta. We observed a strong negative effect of kleptoparasitism (food resource stealing) instead of classical intraguild predation on immature parasitoids. There was no evidence that parasitoid females avoided the omnivorous predator when searching for oviposition sites, although we studied both long- and short-range known detection mechanisms. Therefore, we conclude that broad range cue avoidance may not exist in our biological system, probably because it would lead to too much oviposition site avoidance which would not be an efficient and, thus, beneficial strategy. If confirmed in other parasitoids or specialist predators, our findings may have implications for population dynamics, especially in the current context of increasing invasive species and the resulting creation of many new species associations.

  6. Toxoplasmosis in prey species and consequences for prevalence in feral cats: not all prey species are equal.

    PubMed

    Afonso, E; Thulliez, P; Pontier, D; Gilot-Fromont, E

    2007-12-01

    Toxoplasma gondii is largely transmitted to definitive felid hosts through predation. Not all prey species represent identical risks of infection for cats because of differences in prey susceptibility, exposure and/or lifespan. Previously published studies have shown that prevalence in rodent and lagomorph species is positively correlated with body mass. We tested the hypothesis that different prey species have different infection risks by comparing infection dynamics of feral cats at 4 sites in the sub-Antarctic Kerguelen archipelago which differed in prey availability. Cats were trapped from 1994 to 2004 and anti-T. gondii IgG antibodies were detected using the modified agglutination test (> or =1:40). Overall seroprevalence was 51.09%. Antibody prevalence differed between sites, depending on diet and also on sex, after taking into account the effect of age. Males were more often infected than females and the difference between the sexes tended to be more pronounced in the site where more prey species were available. A difference in predation efficiency between male and female cats may explain this result. Overall, our results suggest that the composition of prey items in cat diet influences the risk of T. gondii infection. Prey compositon should therefore be considered important in any understanding of infection dynamics of T. gondii.

  7. Cues of intraguild predators affect the distribution of intraguild prey.

    PubMed

    Choh, Yasuyuki; van der Hammen, Tessa; Sabelis, Maurice W; Janssen, Arne

    2010-06-01

    Theory on intraguild (IG) predation predicts that coexistence of IG-predators and IG-prey is only possible for a limited set of parameter values, suggesting that IG-predation would not be common in nature. This is in conflict with the observation that IG-predation occurs in many natural systems. One possible explanation for this difference might be antipredator behaviour of the IG-prey, resulting in decreased strength of IG-predation. We studied the distribution of an IG-prey, the predatory mite Neoseiulus cucumeris (Acari: Phytoseiidae), in response to cues of its IG-predator, the predatory mite Iphiseius degenerans. Shortly after release, the majority of IG-prey was found on the patch without cues of IG-predators, suggesting that they can rapidly assess predation risk. IG-prey also avoided patches where conspecific juveniles had been killed by IG-predators. Because it is well known that antipredator behaviour in prey is affected by the diet of the predator, we also tested whether IG-prey change their distribution in response to the food of the IG-predators (pollen or conspecific juveniles), but found no evidence for this. The IG-prey laid fewer eggs on patches with cues of IG-predators than on patches without cues. Hence, IG-prey changed their distribution and oviposition in response to cues of IG-predators. This might weaken the strength of IG-predation, possibly providing more opportunities for IG-prey and IG-predators to co-exist.

  8. Prey-mediated avoidance of an intraguild predator by its intraguild prey

    USGS Publications Warehouse

    Wilson, R.R.; Blankenship, T.L.; Hooten, M.B.; Shivik, J.A.

    2010-01-01

    Intraguild (IG) predation is an important factor influencing community structure, yet factors allowing coexistence of IG predator and IG prey are not well understood. The existence of spatial refuges for IG prey has recently been noted for their importance in allowing coexistence. However, reduction in basal prey availability might lead IG prey to leave spatial refuges for greater access to prey, leading to increased IG predation and fewer opportunities for coexistence. We determined how the availability of prey affected space-use patterns of bobcats (Lynx rufus, IG prey) in relation to coyote space-use patterns (Canis latrans, IG predators). We located animals from fall 2007 to spring 2009 and estimated bobcat home ranges and core areas seasonally. For each bobcat relocation, we determined intensity of coyote use, distance to water, small mammal biomass, and mean small mammal biomass of the home range during the season the location was collected. We built generalized linear mixed models and used Akaike Information Criteria to determine which factors best predicted bobcat space use. Coyote intensity was a primary determinant of bobcat core area location. In bobcat home ranges with abundant prey, core areas occurred where coyote use was low, but shifted to areas intensively used by coyotes when prey declined. High spatial variability in basal prey abundance allowed some bobcats to avoid coyotes while at the same time others were forced into more risky areas. Our results suggest that multiple behavioral strategies associated with spatial variation in basal prey abundance likely allow IG prey and IG predators to coexist. ?? 2010 Springer-Verlag.

  9. Prey-mediated avoidance of an intraguild predator by its intraguild prey.

    PubMed

    Wilson, Ryan R; Blankenship, Terry L; Hooten, Mevin B; Shivik, John A

    2010-12-01

    Intraguild (IG) predation is an important factor influencing community structure, yet factors allowing coexistence of IG predator and IG prey are not well understood. The existence of spatial refuges for IG prey has recently been noted for their importance in allowing coexistence. However, reduction in basal prey availability might lead IG prey to leave spatial refuges for greater access to prey, leading to increased IG predation and fewer opportunities for coexistence. We determined how the availability of prey affected space-use patterns of bobcats (Lynx rufus, IG prey) in relation to coyote space-use patterns (Canis latrans, IG predators). We located animals from fall 2007 to spring 2009 and estimated bobcat home ranges and core areas seasonally. For each bobcat relocation, we determined intensity of coyote use, distance to water, small mammal biomass, and mean small mammal biomass of the home range during the season the location was collected. We built generalized linear mixed models and used Akaike Information Criteria to determine which factors best predicted bobcat space use. Coyote intensity was a primary determinant of bobcat core area location. In bobcat home ranges with abundant prey, core areas occurred where coyote use was low, but shifted to areas intensively used by coyotes when prey declined. High spatial variability in basal prey abundance allowed some bobcats to avoid coyotes while at the same time others were forced into more risky areas. Our results suggest that multiple behavioral strategies associated with spatial variation in basal prey abundance likely allow IG prey and IG predators to coexist.

  10. Predation on heterospecific larvae by adult females of Kampimodromus aberrans, Amblyseius andersoni, Typhlodromus pyri and Phytoseius finitimus (Acari: Phytoseiidae).

    PubMed

    Ahmad, Shakeel; Pozzebon, Alberto; Duso, Carlo

    2015-09-01

    The predatory mites Kampimodromus aberrans (Oudemans), Amblyseius andersoni (Chant), Typhlodromus pyri Scheuten and Phytoseius finitimus Ribaga are important biological control agents in orchards and vineyards in Europe and elsewhere. They can coexist in the same habitat and engage in intraguild predation (IGP). In the laboratory we evaluated the longevity, fecundity and prey consumption of females of these predatory mites fed with heterospecific larvae considered as intraguild prey (IG-prey). The survival and age-specific oviposition curves of predatory mites fed with pollen were compared with those obtained on different IG-prey. We assessed the prey conversion rate into eggs expressed by the different IG-predator as an indicator of their capacity to persist when prey is diminishing. Results suggest that A. andersoni should be considered the superior intraguild predator but the least efficient in food conversion. Phytoseius finitimus appeared to suffer from intraguild predation, and its efficiency in food conversion was not superior to that of K. aberrans and T. pyri. The profiles of K. aberrans and T. pyri were less definite. The comparison between pollen and IG-prey diets confirmed the positive effect of pollen on the fecundity of all four predatory mite species. Fecundity was higher on pollen than on IG-prey. We can suggest that A. andersoni have the potential to exclude the other predatory mites only at high food resource availability, whereas low levels of food availability can favor the other species in IGP.

  11. [IgA-IgG-IgM serum levels in blood donors. Examination of some variables].

    PubMed

    Ghessi, A; Azzario, F; Marinig, C; Mancini, L; Polese, T C; Pozzessere, V

    1976-07-31

    IgA, IgG and IgM serum levels in 603 normal blood donors (510 males and 93 females) have been calculated by the method of single radial immunodiffusion. In every immunoglobulin class the normal values and other important statistical parameters have been determined. Several statistical examinations have been executed to test the influence of some factors as sex, weight, age and number of blood donations on IgA, IgG and IgM serum levels.

  12. Effect of walnut (Juglans regia) polyphenolic compounds on ovalbumin-specific IgE induction in female BALB/c mice.

    PubMed

    Comstock, Sarah S; Gershwin, Laurel J; Teuber, Suzanne S

    2010-03-01

    English walnuts are implicated in severe, IgE-mediated food allergy in humans. We sought to determine if polyphenolic compounds extracted from the edible nut could promote IgE production to a coadministered allergen. BALB/c mice were sensitized to ovalbumin (OVA) with or without alum (AL) or polyphenolic-enriched extract via intraperitoneal injection. Serum was analyzed for total IgE and OVA-specific IgE, IgG(1,) and IgG(2a/2b). Coadministration of walnut polyphenolic-enriched extract with antigen and AL increased serum concentrations of antigen-specific IgE and IgG(1). When AL was excluded from the injections, polyphenolic extract tended to enhance OVA-specific IgE and IgG(1) over levels induced by OVA alone, but the increase did not reach significance. Serum IgG(2a/2b) levels were similar between mice receiving OVA/AL and OVA/AL with polyphenolics. Thus, walnut polyphenolic extract enhanced the Th2-skewing effect of an aluminum hydroxide adjuvant. This indicates that walnut polyphenolic compounds may play a role in allergic sensitization of genetically predisposed individuals.

  13. Intraguild Predation in Heteroptera: Effects of Density and Predator Identity on Dipteran Prey.

    PubMed

    Brahma, S; Sharma, D; Kundu, M; Saha, N; Saha, G K; Aditya, G

    2015-08-01

    In tropical freshwaters, different species of water bugs (Heteroptera) constitute a guild sharing similar prey resources including chironomid and mosquito larvae. Assuming possibilities of intraguild predation (IGP) among the constituent members, an attempt was made to evaluate the effects of prey and predator density on the mortality of mosquito and chironomid larvae (shared prey), using Laccotrephes griseus Guérin-Méneville (Hemiptera: Nepidae) and Ranatra filiformis Fabricius (Hemiptera: Nepidae) as IG predators and Anisops bouvieri Kirkaldy (Hemiptera: Notonectidae) as IG prey. The predation on mosquito and chironomid larvae varied with the density and combinations of the predators. When present as conspecific IG predators, L. griseus exhibited greater effect on the prey mortality than R. filiformis. The effects on shared prey suggest that the two predators are not substitutable in terms of the effect on the shared prey mortality. The mortality of A. bouvieri (IG prey) at low shared prey density was significantly different (p < 0.05) from high shared prey density. In view of predatory effect of the heteropteran predators on the dipteran larvae, the results suggest possible interference by the presence of A. bouvieri as an intermediate predator. It seems that the presence of heteropteran predators including A. bouvieri as IG prey may benefit the dipteran prey under situations when the density is low in tropical waters. The intensity of the predatory effect may differ based on the species composition at IG predator level. For mosquito biological control, the interactions between the predators may not be substitutable and are independent in their effects.

  14. IGS Directory

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The International GPS (Global Positioning System) Service for Geodynamics (IGS) supports and helps coordinate GPS data production and parameters useful for generating more accurate data products. The IGS has operated a GPS tracking system for several years. It contains more than 100 stations worldwide and has produced a combined GPS ephemeris that has become the standard for geodesists and geophysicists worldwide. IGS data and products are freely available to all, thanks to the cooperation and participation of all the IGS members. This directory provides data on the stations and provides names and contact information with personnel involved with the IGS.

  15. Neophobia is negatively related to reversal learning ability in females of a generalist bird of prey, the Chimango Caracara, Milvago chimango.

    PubMed

    Guido, Jorgelina María; Biondi, Laura Marina; Vasallo, Aldo Ivan; Muzio, Rubén Nestor

    2017-03-25

    In an ever-changing environment, the ability to adapt choices to new conditions is essential for daily living and ultimately, for survival. Behavioural flexibility allows animals to maximise survival and reproduction in novel settings by adjusting their behaviour based on specific information and feedback acquired in their current environments. However, a growing body of evidence indicates that an individual's personality type can limit the extent to which the individual might behave flexibly, by influencing the way an individual pays attention to novelty and how much information it collects and stores, which in turn affects the individual's decision-making and learning process. In this study, the behavioural flexibility of a generalist predator, the Chimango Caracara, Milvago chimango, was analysed using the reversal learning paradigm, focusing on the comparison between age classes, and the relation of learning flexibility with a personality trait, the level of neophobia. Due to the low number of male individuals captured, this study was carried out only with female birds. The results showed that age had no significant effect either on the acquisition of a stimulus-reward association, or on the capacity of reversing this previously learned association. Reversal of the response was a harder task for these birds in comparison with the initial acquisition process. The individual's performances in the learning tasks seemed to be uncorrelated with each other, suggesting that they involve different neural mechanisms. Contrary to the general pattern observed in the majority of previous work on personality and cognition in non-human animals, the level of neophobia did not correlate with the initial associative learning performance in both adults and juveniles, yet it showed a significant negative relationship with reversal learning ability, mainly in the regressive phase of this task, for the two age classes. Our results suggest that the predatory and generalist lifestyle

  16. A single predator multiple prey model with prey mutation

    NASA Astrophysics Data System (ADS)

    Mullan, Rory; Abernethy, Gavin M.; Glass, David H.; McCartney, Mark

    2016-11-01

    A multiple species predator-prey model is expanded with the introduction of a coupled map lattice for the prey, allowing the prey to mutate discretely into other prey species. The model is examined in its single predator, multiple mutating prey form. Two unimodal maps are used for the underlying dynamics of the prey species, with different predation strategies being used. Conclusions are drawn on how varying the control parameters of the model governs the overall behaviour and survival of the species. It is observed that in such a complex system, with multiple mutating prey, a large range of non-linear dynamics is possible.

  17. Predators and Prey

    ERIC Educational Resources Information Center

    Kramm, Kenneth R.

    1975-01-01

    Reviews basic concepts of predator-prey interaction, encourages the presentation of the predator's role and describes a model of predator behavior to be used in secondary school or college classes. (LS)

  18. A J-shaped association between serum uric acid levels and poor renal survival in female patients with IgA nephropathy.

    PubMed

    Matsukuma, Yuta; Masutani, Kosuke; Tanaka, Shigeru; Tsuchimoto, Akihiro; Fujisaki, Kiichiro; Torisu, Kumiko; Katafuchi, Ritsuko; Hirakata, Hideki; Tsuruya, Kazuhiko; Kitazono, Takanari

    2017-03-01

    Recently, low serum uric acid (SUA) levels and high SUA levels, have emerged as risk factors for cardiovascular disease, as well as for the incidence of acute kidney injury and chronic kidney disease (CKD). However, the effect of low SUA on the progression of CKD remains unclear. To evaluate the association between SUA and renal prognosis in patients with immunoglobulin A nephropathy (IgAN), one of the most common causes of CKD, we retrospectively followed 1218 patients who were diagnosed with primary IgAN by kidney biopsy between October 1979 and December 2010. Patients were divided into three groups on the basis of SUA level tertiles: low (L group), middle (M group) and high (H group) tertiles (<6.1, 6.1-7.0, and >7.0 mg dl(-1), respectively, for men and <4.4, 4.4-5.3, and >5.3 mg dl(-1), respectively, for women). The risk factors for developing end-stage renal disease (ESRD) were estimated using a Cox proportional hazards model. After a median follow-up of 5.1 years, 142 patients (11.7%) developed ESRD. The hazard ratio (95% confidence interval) showed a J-shaped trend with the tertiles in both men (1.18 (0.55-2.54), 1.00 (reference), and 1.80 (1.01-3.10) in L, M and H groups, respectively) and women (2.73 (1.10-6.76), 1.00 (reference) and 2.49 (1.16-5.34) in L, M and H groups, respectively). Notably, low SUA was significantly associated with incident ESRD in women. This finding suggests that SUA has a J-shaped association with ESRD in patients with IgAN, especially women.

  19. IGS 2000 Annual Report

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Contents: The IGS Governing Board 2000; Central Bureau Status 2000; Growth of the IGS Network in 2000; Analysis Activities; Data Center Activities 2000; The International Terrestrial Reference Frame; IGS Reference Frame Coordination and Working Group Activities; The IGS/BIPM Time and Frequency Pilot Project; IGS Activities in the Area of the Ionosphere 2000; IGS Tropospheric Products; IGS International GLONASS Service Pilot Project; IGS LEO Pilot Project; Continuous GPS Positioning of Tide Gauges.

  20. L-shaped prey isocline in the Gause predator-prey experiments with a prey refuge.

    PubMed

    Křivan, Vlastimil; Priyadarshi, Anupam

    2015-04-07

    Predator and prey isoclines are estimated from data on yeast-protist population dynamics (Gause et al., 1936). Regression analysis shows that the prey isocline is best fitted by an L-shaped function that has a vertical and a horizontal part. The predator isocline is vertical. This shape of isoclines corresponds with the Lotka-Volterra and the Rosenzweig-MacArthur predator-prey models that assume a prey refuge. These results further support the idea that a prey refuge changes the prey isocline of predator-prey models from a horizontal to an L-shaped curve. Such a shape of the prey isocline effectively bounds amplitude of predator-prey oscillations, thus promotes species coexistence.

  1. Seasonal Foraging Ecology of Non-Migratory Cougars in a System with Migrating Prey

    PubMed Central

    Elbroch, L. Mark; Lendrum, Patrick E.; Newby, Jesse; Quigley, Howard; Craighead, Derek

    2013-01-01

    We tested for seasonal differences in cougar (Puma concolor) foraging behaviors in the Southern Yellowstone Ecosystem, a multi-prey system in which ungulate prey migrate, and cougars do not. We recorded 411 winter prey and 239 summer prey killed by 28 female and 10 male cougars, and an additional 37 prey items by unmarked cougars. Deer composed 42.4% of summer cougar diets but only 7.2% of winter diets. Males and females, however, selected different proportions of different prey; male cougars selected more elk (Cervus elaphus) and moose (Alces alces) than females, while females killed greater proportions of bighorn sheep (Ovis canadensis), pronghorn (Antilocapra americana), mule deer (Odocoileus hemionus) and small prey than males. Kill rates did not vary by season or between males and females. In winter, cougars were more likely to kill prey on the landscape as: 1) elevation decreased, 2) distance to edge habitat decreased, 3) distance to large bodies of water decreased, and 4) steepness increased, whereas in summer, cougars were more likely to kill in areas as: 1) elevation decreased, 2) distance to edge habitat decreased, and 3) distance from large bodies of water increased. Our work highlighted that seasonal prey selection exhibited by stationary carnivores in systems with migratory prey is not only driven by changing prey vulnerability, but also by changing prey abundances. Elk and deer migrations may also be sustaining stationary cougar populations and creating apparent competition scenarios that result in higher predation rates on migratory bighorn sheep in winter and pronghorn in summer. Nevertheless, cougar predation on rare ungulates also appeared to be influenced by individual prey selection. PMID:24349498

  2. Seasonal foraging ecology of non-migratory cougars in a system with migrating prey.

    PubMed

    Elbroch, L Mark; Lendrum, Patrick E; Newby, Jesse; Quigley, Howard; Craighead, Derek

    2013-01-01

    We tested for seasonal differences in cougar (Puma concolor) foraging behaviors in the Southern Yellowstone Ecosystem, a multi-prey system in which ungulate prey migrate, and cougars do not. We recorded 411 winter prey and 239 summer prey killed by 28 female and 10 male cougars, and an additional 37 prey items by unmarked cougars. Deer composed 42.4% of summer cougar diets but only 7.2% of winter diets. Males and females, however, selected different proportions of different prey; male cougars selected more elk (Cervus elaphus) and moose (Alces alces) than females, while females killed greater proportions of bighorn sheep (Ovis canadensis), pronghorn (Antilocapra americana), mule deer (Odocoileus hemionus) and small prey than males. Kill rates did not vary by season or between males and females. In winter, cougars were more likely to kill prey on the landscape as: 1) elevation decreased, 2) distance to edge habitat decreased, 3) distance to large bodies of water decreased, and 4) steepness increased, whereas in summer, cougars were more likely to kill in areas as: 1) elevation decreased, 2) distance to edge habitat decreased, and 3) distance from large bodies of water increased. Our work highlighted that seasonal prey selection exhibited by stationary carnivores in systems with migratory prey is not only driven by changing prey vulnerability, but also by changing prey abundances. Elk and deer migrations may also be sustaining stationary cougar populations and creating apparent competition scenarios that result in higher predation rates on migratory bighorn sheep in winter and pronghorn in summer. Nevertheless, cougar predation on rare ungulates also appeared to be influenced by individual prey selection.

  3. Global stability of predator-prey system with alternative prey.

    PubMed

    Sahoo, Banshidhar

    2013-01-01

    A predator-prey model in presence of alternative prey is proposed. Existence and local stability conditions for interior equilibrium points are derived. Global stability conditions for interior equilibrium points are also found. Bifurcation analysis is done with respect to predator's searching rate and handling time. Bifurcation analysis confirms the existence of global stability in presence of alternative prey.

  4. Prey Detection and Prey Capture in Copepod Nauplii

    PubMed Central

    Bruno, Eleonora; Andersen Borg, Christian Marc; Kiørboe, Thomas

    2012-01-01

    Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds numbers due to the thick viscous boundary layer surrounding the attacking nauplius. We use high-speed video to describe the detection and capture of phytoplankton prey by the nauplii of two ambush feeding species (Acartia tonsa and Oithona davisae) and by the nauplii of one feeding-current feeding species (Temora longicornis). We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws in the prey. PMID:23144712

  5. Continuous threshold prey harvesting with vulnerable infected prey

    NASA Astrophysics Data System (ADS)

    Abaas, S.; Abu-Hassn, Y.

    2013-04-01

    In this paper, we introduce a prey-predator model where the susceptible prey becomes infective. We consider the case where the predator will consume the unhealthy prey and at the same time the healthy prey will be harvested. Conditions for the stability of the equilibrium points were obtained. We show when the disease rate is increasing, the trajectories of the general model approach the equilibrium in which all population survive. Also we show that the threshold of harvesting is important because when it approach the size of prey this make the disease increasing so we must start the harvesting so early to control the disease and not become epidemic.

  6. Convergence between a mosquito-eating predator's natural diet and its prey-choice behaviour

    PubMed Central

    Jackson, Robert R.; Deng, Chan

    2016-01-01

    On the basis of 1115 records of Evarcha culicivora feeding in the field, we can characterize this East African jumping spider (Salticidae) as being distinctively stenophagic. We can also, on the basis of laboratory prey-choice experiments, characterize E. culicivora as having a specialized prey-classification system and a hierarchy of innate preferences for various categories of mosquitoes and other arthropods. Prey from the field belonged to 10 arthropod orders, but 94.5% of the prey records were dipterans. Mosquitoes were the dominant prey (80.2% of the records), with the majority (82.9%) of the mosquitoes being females, and thereafter midges were the most common prey (9.2% of the records). Preference profiles that were determined from experiments showed strong convergence with natural diet in some, but not all, instances. In experiments, E. culicivora adults appeared to distinguish between six prey categories and juveniles between seven, with blood-carrying anopheline female mosquitoes being ranked highest in preference. For adults, this was followed by blood-carrying culicine female mosquitoes and then anopheline female mosquitoes not carrying blood, but these two preferences were reversed for juveniles. Moreover, for juveniles, but not for adults, anopheline male mosquitoes seem to be a distinct prey category ranked in preference after blood-carrying culicine females and, for both adults and juveniles, preference for midges is evident when the alternatives are not mosquitoes. These findings illustrate the importance of going beyond simply specifying preferred prey categories when characterizing predators as ‘specialized’ and a need to make clear conceptual distinctions between a predator's natural diet, the prey categories that are relevant to the predator, and the predator's prey-choicebehaviour. PMID:28083103

  7. Unidirectional prey-predator facilitation: apparent prey enhance predators' foraging success on cryptic prey.

    PubMed

    Zhang, Yixin; Richardson, John S

    2007-06-22

    Food availability can strongly affect predator-prey dynamics. When change in habitat condition reduces the availability of one prey type, predators often search for other prey, perhaps in a different habitat. Interactions between behavioural and morphological traits of different prey may influence foraging success of visual predators through trait-mediated indirect interactions (TMIIs), such as prey activity and body coloration. We tested the hypothesis that foraging success of stream-dwelling cutthroat trout (Onchorhyncus clarki) on cryptically coloured, less-active benthic prey (larval mayfly; Paraleptophebia sp.) can be enhanced by the presence of distinctly coloured, active prey (larval stonefly shredder; Despaxia augusta). Cutthroat trout preyed on benthic insects when drifting invertebrates were unavailable. When stonefly larvae were present, the trout ate most of the stoneflies and also consumed a higher proportion of mayflies than under mayfly only treatment. The putative mechanism is that active stonefly larvae supplied visual cues to the predator that alerted trout to the mayfly larvae. Foraging success of visual predators on cryptic prey can be enhanced by distinctly coloured, active benthic taxa through unidirectional facilitation to the predators, which is a functional change of interspecific interaction caused by a third species. This study suggests that prey-predator facilitation through TMIIs can modify species interactions, affecting community dynamics.

  8. Linear IgA/IgG bullous dermatosis: successful treatment with dapsone and mycophenolate mofetil.

    PubMed

    Passos, Leny; Rabelo, Renata Fernandes; Matsuo, Christiane; Santos, Mônica; Talhari, Sinesio; Talhari, Carolina

    2011-01-01

    A 21-year-old female presenting linear IgA and IgG disease initially responded well to dapsone therapy. However, the treatment with dapsone was withdrawn due to severe anemia induced by malaria, which led to worsening of the clinical picture. Although prednisone and methylprednisolone were tried, the patient responded only to the association of dapsone and mycophenolate mofetil.

  9. Predator-prey systems depend on a prey refuge.

    PubMed

    Chivers, W J; Gladstone, W; Herbert, R D; Fuller, M M

    2014-11-07

    Models of near-exclusive predator-prey systems such as that of the Canadian lynx and snowshoe hare have included factors such as a second prey species, a Holling Type II predator response and climatic or seasonal effects to reproduce sub-sets of six signature patterns in the empirical data. We present an agent-based model which does not require the factors or constraints of previous models to reproduce all six patterns in persistent populations. Our parsimonious model represents a generalised predator and prey species with a small prey refuge. The lack of the constraints of previous models, considered to be important for those models, casts doubt on the current hypothesised mechanisms of exclusive predator-prey systems. The implication for management of the lynx, a protected species, is that maintenance of an heterogeneous environment offering natural refuge areas for the hare is the most important factor for the conservation of this species.

  10. Ecoepidemic predator-prey model with feeding satiation, prey herd behavior and abandoned infected prey.

    PubMed

    Kooi, Bob W; Venturino, Ezio

    2016-04-01

    In this paper we analyse a predator-prey model where the prey population shows group defense and the prey individuals are affected by a transmissible disease. The resulting model is of the Rosenzweig-MacArthur predator-prey type with an SI (susceptible-infected) disease in the prey. Modeling prey group defense leads to a square root dependence in the Holling type II functional for the predator-prey interaction term. The system dynamics is investigated using simulations, classical existence and asymptotic stability analysis and numerical bifurcation analysis. A number of bifurcations, such as transcritical and Hopf bifurcations which occur commonly in predator-prey systems will be found. Because of the square root interaction term there is non-uniqueness of the solution and a singularity where the prey population goes extinct in a finite time. This results in a collapse initiated by extinction of the healthy or susceptible prey and thereafter the other population(s). When also a positive attractor exists this leads to bistability similar to what is found in predator-prey models with a strong Allee effect. For the two-dimensional disease-free (i.e. the purely demographic) system the region in the parameter space where bistability occurs is marked by a global bifurcation. At this bifurcation a heteroclinic connection exists between saddle prey-only equilibrium points where a stable limit cycle together with its basin of attraction, are destructed. In a companion paper (Gimmelli et al., 2015) the same model was formulated and analysed in which the disease was not in the prey but in the predator. There we also observed this phenomenon. Here we extend its analysis using a phase portrait analysis. For the three-dimensional ecoepidemic predator-prey system where the prey is affected by the disease, also tangent bifurcations including a cusp bifurcation and a torus bifurcation of limit cycles occur. This leads to new complex dynamics. Continuation by varying one parameter

  11. Birds of Prey of Wisconsin.

    ERIC Educational Resources Information Center

    Hamerstrom, Frances

    This copiously illustrated document is designed to be a field quide to birds of prey that are common to Wisconsin, as well as to some that enter the state occasionally. An introduction discusses birds of prey with regard to migration patterns, the relationship between common names and the attitudes of people toward certain birds, and natural signs…

  12. Prey use and provisioning rates of urban-nesting Mississippi Kites in west Texas

    USGS Publications Warehouse

    Welch, Brandi C.; Boal, Clint W.

    2015-01-01

    Urban ecosystems are attractive to several raptor species, including the Mississippi Kite (Ictinia mississippiensis). To better understand the niche filled by urban-nesting Mississippi Kites, we observed nesting kites at 10 nests for a total of 269 hr during the breeding seasons of 2010 and 2011. We assessed prey delivery rates and prey use within and between years, evaluated the influences of nestling age, time of day, day of year, and local atmospheric conditions on delivery rates, and examined provisioning rates by male and female kites. A 62% decrease in the prey delivery rate, measured by the number of prey deliveries, from 2010 to 2011 was likely attributable to extreme heat and drought during the 2011 breeding season. However, total biomass of identified deliveries increased 38.9% in 2011 due to an increase in the percentage of avian prey (from 1% to 16% of identified deliveries). We suspect that differences in weather conditions between years influenced the type of prey delivered, and our modeling efforts indicated that year, nestling age, time of day, and temperature best explained the number of prey deliveries made per hour. On average, females delivered more prey items than males, but variability among nests suggested additional factors may influence parental effort. Our results suggest that Mississippi Kites exhibit prey switching under differing conditions.

  13. IgA Nephropathy.

    PubMed

    Rodrigues, Jennifer C; Haas, Mark; Reich, Heather N

    2017-02-03

    IgA nephropathy (IgAN) is a leading cause of CKD and renal failure. Recent international collaborative efforts have led to important discoveries that have improved our understanding of some of the key steps involved in the immunopathogenesis of IgAN. Furthermore, establishment of multicenter networks has contributed to rigorous design and execution of clinical trials that have provided important insights regarding immunotherapy in IgAN. In this article, we review emerging developments in clinical and translational IgAN research and describe how these novel findings will influence future strategies to improve the outcome of patients with IgAN.

  14. Prey-predator model with a nonlocal consumption of prey

    NASA Astrophysics Data System (ADS)

    Banerjee, M.; Volpert, V.

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.

  15. Prey-predator model with a nonlocal consumption of prey.

    PubMed

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.

  16. IgA nephropathy

    MedlinePlus

    ... disease. Causes IgA is a protein, called an antibody , that helps the body fight infections. IgA nephropathy occurs when too much of this protein is deposited in the kidneys. IgA builds up inside the small blood vessels of the kidney. Structures in the kidney called glomeruli become inflamed and ...

  17. Behavioral refuges and predator-prey coexistence.

    PubMed

    Křivan, Vlastimil

    2013-12-21

    The effects of a behavioral refuge caused either by the predator optimal foraging or prey adaptive antipredator behavior on the Gause predator-prey model are studied. It is shown that both of these mechanisms promote predator-prey coexistence either at an equilibrium, or along a limit cycle. Adaptive prey refuge use leads to hysteresis in prey antipredator behavior which allows predator-prey coexistence along a limit cycle. Similarly, optimal predator foraging leads to sigmoidal functional responses with a potential to stabilize predator-prey population dynamics at an equilibrium, or along a limit cycle.

  18. Prey detection in a cruising copepod

    PubMed Central

    Kjellerup, Sanne; Kiørboe, Thomas

    2012-01-01

    Small cruising zooplankton depend on remote prey detection and active prey capture for efficient feeding. Direct, passive interception of prey is inherently very inefficient at low Reynolds numbers because the viscous boundary layer surrounding the approaching predator will push away potential prey. Yet, direct interception has been proposed to explain how rapidly cruising, blind copepods feed on non-motile phytoplankton prey. Here, we demonstrate a novel mechanism for prey detection in a cruising copepod, and describe how motile and non-motile prey are discovered by hydromechanical and tactile or, likely, chemical cues, respectively. PMID:22158738

  19. Prey detection in a cruising copepod.

    PubMed

    Kjellerup, Sanne; Kiørboe, Thomas

    2012-06-23

    Small cruising zooplankton depend on remote prey detection and active prey capture for efficient feeding. Direct, passive interception of prey is inherently very inefficient at low Reynolds numbers because the viscous boundary layer surrounding the approaching predator will push away potential prey. Yet, direct interception has been proposed to explain how rapidly cruising, blind copepods feed on non-motile phytoplankton prey. Here, we demonstrate a novel mechanism for prey detection in a cruising copepod, and describe how motile and non-motile prey are discovered by hydromechanical and tactile or, likely, chemical cues, respectively.

  20. The discerning predator: decision rules underlying prey classification by a mosquito-eating jumping spider

    PubMed Central

    Nelson, Ximena J.; Jackson, Robert R.

    2012-01-01

    SUMMARY Evarcha culicivora is an East African jumping spider that feeds indirectly on vertebrate blood by choosing blood-fed female Anopheles mosquitoes as prey. Previous studies have shown that this predator can identify its preferred prey even when restricted to using only visual cues. Here, we used lures and virtual mosquitoes to investigate the optical cues underlying this predator's prey-choice behaviour. We made lures by dissecting and then reconstructing dead mosquitoes, combining the head plus thorax with different abdomens. Depending on the experiment, lures were either moving or motionless. Findings from the lure experiments suggested that, for E. culicivora, seeing a blood-fed female mosquito's abdomen on a lure was a necessary, but not sufficient, cue by which preferred prey was identified, as cues from the abdomen needed to be paired with cues from the head and thorax of a mosquito. Conversely, when abdomens were not visible or were identical, spiders based their decisions on the appearance of the head plus thorax of mosquitoes, choosing prey with female characteristics. Findings from a subsequent experiment using animated 3D virtual mosquitoes suggest that it is specifically the mosquito's antennae that influence E. culicivora's prey-choice decisions. Our results show that E. culicivora uses a complex process for prey classification. PMID:22675186

  1. Phase transitions in predator-prey systems

    NASA Astrophysics Data System (ADS)

    Nagano, Seido; Maeda, Yusuke

    2012-01-01

    The relationship between predator and prey plays an important role in ecosystem conservation. However, our understanding of the principles underlying the spatial distribution of predators and prey is still poor. Here we present a phase diagram of a predator-prey system and investigate the lattice formation in such a system. We show that the production of stable lattice structures depends on the limited diffusion or migration of prey as well as higher carrying capacity for the prey. In addition, when the prey's growth rate is lower than the birth rate of the predator, global prey lattice formation is initiated by microlattices at the center of prey spirals. The predator lattice is later formed in the predator spirals. But both lattice formations proceed together as the prey growth rate increases.

  2. Relating wolf scat content to prey consumed

    USGS Publications Warehouse

    Floyd, T.J.; Mech, L.D.; Jordan, P.A.

    1978-01-01

    In 9 trials, captive wolves (Canis lupus) were fed prey varying in size from snowshoe hares (Lepus americanus) to adult deer (Odocoileus virginianus), and the resulting scats were counted. Field-collectible scats were distinguished from liquid, noncollectible stools. I n collectible scats, the remains of small prey occurred in greater proportion relative to the prey's weight, and in lesser proportion relative to the prey's numbers, than did the remains of larger prey. A regression equation with an excellent, fit to the data (r2 = 0.97) was derived to estimate the weight of prey eaten per collectible scat for any prey. With this information and average prey weights, the relative numbers of different prey eaten also can be calculated.

  3. IgA nephropathy.

    PubMed

    Lai, Kar Neng; Tang, Sydney C W; Schena, Francesco Paolo; Novak, Jan; Tomino, Yasuhiko; Fogo, Agnes B; Glassock, Richard J

    2016-02-11

    Globally, IgA nephropathy (IgAN) is the most common primary glomerulonephritis that can progress to renal failure. The exact pathogenesis of IgAN is not well defined, but current biochemical and genetic data implicate overproduction of aberrantly glycosylated IgA1. These aberrant immunoglobulins are characterized by galactose deficiency of some hinge-region O-linked glycans. However, aberrant glycosylation alone is insufficient to induce renal injury: the participation of glycan-specific IgA and IgG autoantibodies that recognize the undergalactosylated IgA1 molecule is required. Glomerular deposits of immune complexes containing undergalactosylated IgA1 activate mesangial cells, leading to the local overproduction of cytokines, chemokines and complement. Emerging data indicate that mesangial-derived mediators that are released following mesangial deposition of IgA1 lead to podocyte and tubulointerstitial injury via humoral crosstalk. Patients can present with a range of signs and symptoms, from asymptomatic microscopic haematuria to macroscopic haematuria. The clinical progression varies, with 30-40% of patients reaching end-stage renal disease 20-30 years after the first clinical presentation. Currently, no IgAN-specific therapies are available and patients are managed with the aim of controlling blood pressure and maintaining renal function. However, new therapeutic approaches are being developed, building upon our ever-improving understanding of disease pathogenesis.

  4. Predator-prey system with strong Allee effect in prey.

    PubMed

    Wang, Jinfeng; Shi, Junping; Wei, Junjie

    2011-03-01

    Global bifurcation analysis of a class of general predator-prey models with a strong Allee effect in prey population is given in details. We show the existence of a point-to-point heteroclinic orbit loop, consider the Hopf bifurcation, and prove the existence/uniqueness and the nonexistence of limit cycle for appropriate range of parameters. For a unique parameter value, a threshold curve separates the overexploitation and coexistence (successful invasion of predator) regions of initial conditions. Our rigorous results justify some recent ecological observations, and practical ecological examples are used to demonstrate our theoretical work.

  5. Geometric optimization for prey-predator strategies.

    PubMed

    Alshamary, Bader; Calin, Ovidiu

    2011-11-01

    This paper investigates several strategies for prey and predator in both bounded and unbounded domains, assuming they have the same speed. The work describes how the prey should move to escape from the predator and how predator should move to catch the prey. The approach is agent-based and explicitly tracks movement of individuals as prey and predator. We show that the prey escapes one or two competing predators, while might be caught in the case of three predators. The paper also describes a strategy for finding a well camouflaged static prey which emits signals.

  6. [IgG4 immunohistochemistry in Riedle thyroiditis].

    PubMed

    Wang, S; Luo, Y F; Cao, J L; Zhang, H; Shi, X H; Liang, Z Y; Feng, R E

    2017-03-08

    Objective: To observe the histopathological changes and immunohistochemical expression of IgG4 in Riedle thyroiditis (RT) and to study the relationship between RT and IgG4-related diseases (IgG4-RD). Methods: A total of 5 RT patients were collected from the Department of Pathology, Peking Union Medical College Hospital during April 2012 to August 2014. The clinical and immunohistochemical features were analyzed in the 5 patients. Histopathologic analysis was performed on hematoxylin and eosin-stained sections. Results: There were one male and four female patients, aged 52 to 78 years (median 59 years). Five cases were characterized by multiple nodules of thyroid, which increased year by year. All patients were found to have surrounding tissue compression symptoms and signs. Two female patients were found to have hypothyroidism. The serum concentration of IgG was elevated in 2 cases, and the serum concentration of IgG was not tested before operation in the remaining patients. By ultrasound, all presented as low echo or medium low echo. Strong echo occasionally appeared in hypoechoic nodules. Microscopically, fibrous tissue hyperplasia was infiltrated with varying numbers of lymphocytes and plasma cells. The occlusion of phlebitis was found in 4 cases and eosinophils were found in 3 cases. IgG4 counts and IgG4/IgG ratios in 5 cases were 20/HPF, 16%; 60/HPF, 82%; 22/HPF, 28%; 400/HPF, 266% and 33/HPF, 71%, respectively. Conclusions: With the similar pathological manifestations between RT and IgG4-RD, immunohistochemical staining shows that the number of IgG4 positive plasma cells and IgG4/IgG ratio of RT are increased in varying degrees. Some cases meet the diagnostic criteria of IgG4-RD, and speculate that some cases of RT belong to IgG4-RD.

  7. Top carnivores increase their kill rates on prey as a response to human-induced fear.

    PubMed

    Smith, Justine A; Wang, Yiwei; Wilmers, Christopher C

    2015-03-07

    The fear induced by predators on their prey is well known to cause behavioural adjustments by prey that can ripple through food webs. Little is known, however, about the analogous impacts of humans as perceived top predators on the foraging behaviour of carnivores. Here, we investigate the influence of human-induced fear on puma foraging behaviour using location and prey consumption data from 30 tagged individuals living along a gradient of human development. We observed strong behavioural responses by female pumas to human development, whereby their fidelity to kill sites and overall consumption time of prey declined with increasing housing density by 36 and 42%, respectively. Females responded to this decline in prey consumption time by increasing the number of deer they killed in high housing density areas by 36% over what they killed in areas with little residential development. The loss of food from declines in prey consumption time paired with increases in energetic costs associated with killing more prey may have consequences for puma populations, particularly with regard to reproductive success. In addition, greater carcass availability is likely to alter community dynamics by augmenting food resources for scavengers. In light of the extensive and growing impact of habitat modification, our study emphasizes that knowledge of the indirect effects of human activity on animal behaviour is a necessary component in understanding anthropogenic impacts on community dynamics and food web function.

  8. Tigers and their prey: Predicting carnivore densities from prey abundance

    USGS Publications Warehouse

    Karanth, K.U.; Nichols, J.D.; Kumar, N.S.; Link, W.A.; Hines, J.E.

    2004-01-01

    The goal of ecology is to understand interactions that determine the distribution and abundance of organisms. In principle, ecologists should be able to identify a small number of limiting resources for a species of interest, estimate densities of these resources at different locations across the landscape, and then use these estimates to predict the density of the focal species at these locations. In practice, however, development of functional relationships between abundances of species and their resources has proven extremely difficult, and examples of such predictive ability are very rare. Ecological studies of prey requirements of tigers Panthera tigris led us to develop a simple mechanistic model for predicting tiger density as a function of prey density. We tested our model using data from a landscape-scale long-term (1995-2003) field study that estimated tiger and prey densities in 11 ecologically diverse sites across India. We used field techniques and analytical methods that specifically addressed sampling and detectability, two issues that frequently present problems in macroecological studies of animal populations. Estimated densities of ungulate prey ranged between 5.3 and 63.8 animals per km2. Estimated tiger densities (3.2-16.8 tigers per 100 km2) were reasonably consistent with model predictions. The results provide evidence of a functional relationship between abundances of large carnivores and their prey under a wide range of ecological conditions. In addition to generating important insights into carnivore ecology and conservation, the study provides a potentially useful model for the rigorous conduct of macroecological science.

  9. Pattern formation in prey-taxis systems.

    PubMed

    Lee, J M; Hillen, T; Lewis, M A

    2009-11-01

    In this paper, we consider spatial predator-prey models with diffusion and prey-taxis. We investigate necessary conditions for pattern formation using a variety of non-linear functional responses, linear and non-linear predator death terms, linear and non-linear prey-taxis sensitivities, and logistic growth or growth with an Allee effect for the prey. We identify combinations of the above non-linearities that lead to spatial pattern formation and we give numerical examples. It turns out that prey-taxis stabilizes the system and for large prey-taxis sensitivity we do not observe pattern formation. We also study and find necessary conditions for global stability for a type I functional response, logistic growth for the prey, non-linear predator death terms, and non-linear prey-taxis sensitivity.

  10. Innate prey preference overridden by familiarisation with detrimental prey in a specialised myrmecophagous predator

    NASA Astrophysics Data System (ADS)

    Pekár, Stano; Cárdenas, Manuel

    2015-02-01

    Prey-specialised spiders often do not have brood care and may not deposit eggs in the proximity of the preferred prey. Thus, naïve spiderlings are left to their own to find their focal prey. Our aim was to reveal whether the choice of a specific prey is innate and whether familiarisation with a certain prey will condition prey choice. We used the myrmecophagous spider Euryopis episinoides, which specialises on Messor ants. It finds ants using chemical cues deposited on the substrate. Naïve spiderlings were offered chemical cues from Messor and Myrmica ants and Drosophila flies. They chose significantly more chemical cues from Messor ants than those from Drosophila flies. Then spiderlings were assigned to three prey treatments: fed with Messor ants only (optimal prey), fed with Myrmica ants only (suboptimal prey) or fed with Drosophila flies only (detrimental prey) until adulthood. Every 2 weeks, all spiders from all treatments were offered chemical cues from the three prey types and the frequency of choice and latency to assuming a posture were recorded. Experienced spiderlings preferred chemical cues from the prey in which they were raised. They suffered high mortality on Drosophila flies and attained largest size on the optimal prey. We show here that majority of spiderlings are born with an innate preference to their focal prey, which can be altered by familiarisation with alternative prey, irrespective of whether such a prey is beneficial.

  11. Integrity monitoring of IGS products

    NASA Technical Reports Server (NTRS)

    Zumberge, James F.; Plag, H. -P.

    2005-01-01

    The IGS has successfully produced precise GPS and GLONASS transmitter parameters, coordinates of IGS tracking stations, Earth rotation parameters, and atmospheric parameters. In this paper we discuss the concepts of integrity monitoring, system monitoring, and performance assessment, all in the context of IGS products. We report on a recent survey of IGS product users, and propose an integrity strategy for the IGS.

  12. The Predator-Prey Relationship

    ERIC Educational Resources Information Center

    Mitchell, Charles W.

    1977-01-01

    Many children develop a mistaken attitude about the predator-prey relationship in the ecosystem. Fairy tales portray the predator as evil or worthless. This article attempts to clarify the role of the predator by giving numerous examples of the value of predators. (MA)

  13. Prey-mediated effects of transgenic canola on a beneficial, non-target, carabid beetle.

    PubMed

    Ferry, Natalie; Mulligan, Evan A; Stewart, C Neal; Tabashnik, Bruce E; Port, Gordon R; Gatehouse, Angharad M R

    2006-08-01

    Transgenic plants producing insecticidal proteins from Bacillus thuringiensis (Bt) can control some major insect pests and reduce reliance on sprayed insecticides. However, large scale adoption of this technology has raised concerns about potential negative effects, including evolution of pest resistance to Bt toxins, transgene flow from Bt crops to other plants, and harm to non-target beneficial organisms. Furthermore, concern has also been expressed over the effects this technology may have on biodiversity in general. Ecologically relevant risk assessment is therefore required (Risk = Hazard x Exposure). Transgenic plants that produce Bt toxins to kill insect pests could harm beneficial predators. This might occur directly by transmission of toxin via prey, or indirectly by toxin-induced reduction in prey quality (Hazard). To test these hypotheses, we determined the effects of Bt-producing canola on a predatory ground beetle (Pterostichus madidus) fed larvae of diamondback moth (Plutella xylostella) that were either susceptible or resistant to the Bt toxin. Survival, weight gain, and adult reproductive fitness did not differ between beetles fed prey reared on Bt-producing plants and those fed prey from control plants. Furthermore, while Bt-resistant prey was shown to deliver high levels of toxin to the beetle when they were consumed, no significant impact upon the beetle was observed. Subsequent investigation showed that in choice tests (Exposure), starved and partially satiated female beetles avoided Bt-fed susceptible prey, but not Bt-fed resistant prey. However, in the rare cases when starved females initially selected Bt-fed susceptible prey, they rapidly rejected them after beginning to feed. This prey type was shown to provide sufficient nutrition to support reproduction in the bioassay suggesting that Bt-fed susceptible prey is acceptable in the absence of alternative prey, however adults possess a discrimination ability based on prey quality. These

  14. Prey stage preference and functional response of Euseius hibisci to Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae).

    PubMed

    Badii, Mohammad H; Hernández-Ortiz, Emilio; Flores, Adriana E; Landeros, Jerónimo

    2004-01-01

    The aims of this study were: (a) determine the prey stage preference of female Euseius hibisci (Chant) (Phytoseiidae) at constant densities of different stages of Tetranychus urticae Koch (Tetranychidae), (b) assess the functional response of the predator females to the varying densities of eggs, larvae, or protonymphs of T. urticae, and (c) estimate the functional response of E. hibisci when pollen of Ligustrum ovalifolium was present as well. We conducted experiments on excised pieces of strawberry leaf arenas (Fragaria ananassa) under laboratory conditions of 25+/-2 degrees C, 60+/-5% RH and 12 h photophase. Our results indicated that the predator consumed significantly more prey eggs than other prey stages. Consumption of prey deutonymphs and adults was so low that they were excluded from the non-choice functional response experiments. The functional response on all food items was of type II. The two parameters of the functional response were estimated for each prey type by means of the adjusted non-linear regression model. The highest estimated value a' (instantaneous rate of discovery) and the lowest value of Th (handling time, including digestion) were found for the predator feeding on prey eggs, and a' was lowest and Th highest when fed protonymphs. Using the jack-knife method, the values for the functional response parameters were estimated. The values of a' and Th produced by the model were similar among all prey types except for the eggs, which were different. Using pollen simultaneously with prey larvae decreased the consumption of the latter over the full range of prey densities The suitability of this predator for biological control of T. urticae on strawberry is discussed.

  15. Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences

    PubMed Central

    Kojima, Yosuke; Mori, Akira

    2015-01-01

    Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring. PMID:25392472

  16. Is the red spotted green frog Hypsiboas punctatus (Anura: Hylidae) selecting its preys? The importance of prey availability.

    PubMed

    López, Javier A; Scarabotti, Pablo A; Medrano, María C; Ghirardi, Romina

    2009-09-01

    The study of the feeding ecology of amphibians is an old issue in herpetology. Notwithstanding, the lack of food resources data in many studies of amphibians feeding has lead to partial understanding of frog feeding strategies. In this study we evaluate the trophic selectivity of a red spotted green frog (Hypsiboas punctatus) population from a Middle Paraná River floodplain pond in Argentina, and discuss the importance of prey availability data when interpreting results from diet analysis. We analyzed the gut contents of 47 H. punctatus adults and compared frog's diet with the environmental food resources. Prey availability was estimated by systematically seep-netting the microhabitat where anurans were localized foraging. We identified 33 taxonomic categories from gastrointestinal contents. Numerically, the most important prey categories were dipterans, followed by hemipterans, homopterans and coleopterans. The diet similarity between males and females was high and no statistical differences in diet composition were found. The most abundant food resources in the environment were dipterans, coleopterans, homopterans and collembolans. In order to assess whether frogs were selecting their preys, we calculated Pianka's niche overlap index and Jacobs' electivity index comparing gut contents to prey availability data. Trophic niche overlap was medium but significantly higher than expected by chance. The electivity index indicated that H. punctatus foraged dipterans slightly above their environmental abundance. Among the secondary preys, hemipterans were foraged selectively, homopterans were consumed in the same proportion to their occurrence in the environment, coleopterans were foraged quite under their availability and collembolans were practically ignored by frogs. Without food resources data, H. punctatus could be classified as a specialist feeder, but dipterans also were quite abundant in the environment. Our results show that H. punctatus fit better as a

  17. Adult Prey Neutralizes Predator Nonconsumptive Limitation of Prey Recruitment

    PubMed Central

    Scrosati, Ricardo A.; Romoth, Katharina; Molis, Markus

    2016-01-01

    Recent studies have shown that predator chemical cues can limit prey demographic rates such as recruitment. For instance, barnacle pelagic larvae reduce settlement where predatory dogwhelk cues are detected, thereby limiting benthic recruitment. However, adult barnacles attract conspecific larvae through chemical and visual cues, aiding larvae to find suitable habitat for development. Thus, we tested the hypothesis that the presence of adult barnacles (Semibalanus balanoides) can neutralize dogwhelk (Nucella lapillus) nonconsumptive effects on barnacle recruitment. We did a field experiment in Atlantic Canada during the 2012 and 2013 barnacle recruitment seasons (May–June). We manipulated the presence of dogwhelks (without allowing them to physically contact barnacles) and adult barnacles in cages established in rocky intertidal habitats. At the end of both recruitment seasons, we measured barnacle recruit density on tiles kept inside the cages. Without adult barnacles, the nearby presence of dogwhelks limited barnacle recruitment by 51%. However, the presence of adult barnacles increased barnacle recruitment by 44% and neutralized dogwhelk nonconsumptive effects on barnacle recruitment, as recruit density was unaffected by dogwhelk presence. For species from several invertebrate phyla, benthic adult organisms attract conspecific pelagic larvae. Thus, adult prey might commonly constitute a key factor preventing negative predator nonconsumptive effects on prey recruitment. PMID:27123994

  18. Adult Prey Neutralizes Predator Nonconsumptive Limitation of Prey Recruitment.

    PubMed

    Ellrich, Julius A; Scrosati, Ricardo A; Romoth, Katharina; Molis, Markus

    2016-01-01

    Recent studies have shown that predator chemical cues can limit prey demographic rates such as recruitment. For instance, barnacle pelagic larvae reduce settlement where predatory dogwhelk cues are detected, thereby limiting benthic recruitment. However, adult barnacles attract conspecific larvae through chemical and visual cues, aiding larvae to find suitable habitat for development. Thus, we tested the hypothesis that the presence of adult barnacles (Semibalanus balanoides) can neutralize dogwhelk (Nucella lapillus) nonconsumptive effects on barnacle recruitment. We did a field experiment in Atlantic Canada during the 2012 and 2013 barnacle recruitment seasons (May-June). We manipulated the presence of dogwhelks (without allowing them to physically contact barnacles) and adult barnacles in cages established in rocky intertidal habitats. At the end of both recruitment seasons, we measured barnacle recruit density on tiles kept inside the cages. Without adult barnacles, the nearby presence of dogwhelks limited barnacle recruitment by 51%. However, the presence of adult barnacles increased barnacle recruitment by 44% and neutralized dogwhelk nonconsumptive effects on barnacle recruitment, as recruit density was unaffected by dogwhelk presence. For species from several invertebrate phyla, benthic adult organisms attract conspecific pelagic larvae. Thus, adult prey might commonly constitute a key factor preventing negative predator nonconsumptive effects on prey recruitment.

  19. Global stability of prey-taxis systems

    NASA Astrophysics Data System (ADS)

    Jin, Hai-Yang; Wang, Zhi-An

    2017-02-01

    In this paper, we prove the global boundedness and stability of the predator-prey system with prey-taxis in a two-dimensional bounded domain with Neumann boundary conditions. By deriving an entropy-like equality and a boundedness criterion, we show that the intrinsic interaction between predators and preys is sufficient to prevent the population overcrowding even the prey-taxis is included and strong. Furthermore, by constructing appropriate Lyapunov functionals, we show that prey-only steady state is globally asymptotically stable if the predation is weak, and the co-existence steady state is globally asymptotically stable under some conditions (like the prey-taxis is weak or the prey diffuses fast) if the predation is strong. The convergence rates of solutions to the steady states are derived in the paper.

  20. Prey pursuit and interception in dragonflies.

    PubMed

    Olberg, R M; Worthington, A H; Venator, K R

    2000-02-01

    Perching dragonflies (Libellulidae; Odonata) are sit-and-wait predators, which take off and pursue small flying insects. To investigate their prey pursuit strategy, we videotaped 36 prey-capture flights of male dragonflies, Erythemis simplicicollis and Leucorrhinia intacta, for frame-by-frame analysis. We found that dragonflies fly directly toward the point of prey interception by steering to minimize the movement of the prey's image on the retina. This behavior could be guided by target-selective descending interneurons which show directionally selective visual responses to small-object movement. We investigated how dragonflies discriminate distance of potential prey. We found a peak in angular velocity of the prey shortly before take-off which might cue the dragonfly to nearby flying targets. Parallax information from head movements was not required for successful prey pursuit.

  1. When attempts at robbing prey turn fatal

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Corbara, Bruno; Azémar, Frédéric; Carpenter, James M.

    2012-07-01

    Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1 %) were captured in turn. The ant workers hunt in a group and use the "Velcro®" principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases.

  2. Continuous traveling waves for prey-taxis.

    PubMed

    Lee, J M; Hillen, T; Lewis, M A

    2008-04-01

    Spatially moving predators are often considered for biological control of invasive species. The question arises as to whether introduced predators are able to stop an advancing pest or foreign population. In recent studies of reaction-diffusion models, it has been shown that the prey invasion can only be stopped if the prey dynamics observes an Allee effect. In this paper, we include prey-taxis into the model. Prey-taxis describe the active movement of predators to regions of high prey density. This effect leads to the observation that predators are drawn away from the leading edge of a prey invasion where its density is low. This leads to counterintuitive result that prey-taxis can actually reduce the likelihood of effective biocontrol.

  3. Individual variation in prey selection by sea otters: Patterns, causes and implications

    USGS Publications Warehouse

    Estes, J.A.; Riedman, M.L.; Staedler, M.M.; Tinker, M.T.; Lyon, B.E.

    2003-01-01

    1. Longitudinal records of prey selection by 10 adult female sea otters on the Monterey Peninsula, California, from 1983 to 1990 demonstrate extreme inter-individual variation in diet. Variation in prey availability cannot explain these differences as the data were obtained from a common spatial-temporal area. 2. Individual dietary patterns persisted throughout our study, thus indicating that they are life-long characteristics. 3. Individual dietary patterns in sea otters appear to be transmitted along matrilines, probably by way of learning during the period of mother-young association. 4. Efficient utilization of different prey types probably requires radically different sensory/motor skills, each of which is difficult to acquire and all of which may exceed the learning and performance capacities of any single individual. This would explain the absence of generalists and inertia against switching, but not the existence of alternative specialists. 5. Such individual variation might arise in a constant environment from frequency-dependent effects, whereby the relative benefit of a given prey specialization depends on the number of other individuals utilizing that prey. Additionally, many of the sea otter's prey fluctuate substantially in abundance through time. This temporal variation, in conjunction with matrilineal transmission of foraging skills, may act to mediate the temporal dynamics of prey specializations. 6. Regardless of the exact cause, such extreme individual variation in diet has broad ramifications for population and community ecology. 7. The published literature indicates that similar patterns occur in many other species.

  4. [IgA nephropathy].

    PubMed

    Basta-Jovanović, Gordana

    2004-01-01

    IgA nephropathy is glomerular disease first described in 1968 by Berger, named after him Morbus Berger. The disease is characterized by the presence of IgA dominant or codominant immunoglobulin deposits in glomerular mesangium which can be demonstrated by immunofluorescence. Clinical manifestations of IgA nephropathy in the majority of cases is hematuria which can be macro or microscopic, isolated or combined with proteinuria which can be of nephrotic range. In some cases nephrotic syndrome can be the first clinical presentation. In 10% renal insufficiency can be present at the onset of the disease. By light microscopy IgA can manifest any of the histologic phenotypes of immune complex mediated proliferative glomerulonephritis. According to light microscopy findings a classification system have been used to categorize the histologic patterns of IgA nephropathy. Glomerular changes in IgA nephropathy are proliferative and can be focal or diffuse accompanied by crescentic formation in many cases. Immune deposits seen by electron microscopy appear as electron dense deposits most numerous in mesangium.

  5. The effect of prey refuge in a patchy predator-prey system.

    PubMed

    Ma, Zhihui; Wang, Shufan; Li, Weide; Li, Zizhen

    2013-05-01

    In this work, we proposed a patchy predator-prey model with one patch as refuge and the other as open habitat, and incorporated prey refuge in the considered model explicitly. We applied an analytical approach to study the dynamic consequences of the simplest forms of refuge used by prey and the migration efficiency. The results have shown that the refuge used by prey and the migration efficiency play an important role in the dynamic consequences of the interacting populations and the equilibrium density of two interacting populations. This work also proposed a new approach which can incorporate prey refuge in predator-prey system explicitly.

  6. Optimal forager against ideal free distributed prey.

    PubMed

    Garay, József; Cressman, Ross; Xu, Fei; Varga, Zoltan; Cabello, Tomás

    2015-07-01

    The introduced dispersal-foraging game is a combination of prey habitat selection between two patch types and optimal-foraging approaches. Prey's patch preference and forager behavior determine the prey's survival rate. The forager's energy gain depends on local prey density in both types of exhaustible patches and on leaving time. We introduce two game-solution concepts. The static solution combines the ideal free distribution of the prey with optimal-foraging theory. The dynamical solution is given by a game dynamics describing the behavioral changes of prey and forager. We show (1) that each stable equilibrium dynamical solution is always a static solution, but not conversely; (2) that at an equilibrium dynamical solution, the forager can stabilize prey mixed patch use strategy in cases where ideal free distribution theory predicts that prey will use only one patch type; and (3) that when the equilibrium dynamical solution is unstable at fixed prey density, stable behavior cycles occur where neither forager nor prey keep a fixed behavior.

  7. 2D immunoblots show differential response of mouse IgG and IgM antibodies to antigens of mammary carcinoma 4 T1 cells

    PubMed Central

    2014-01-01

    Background Immunosuppression in breast cancer has been reported in women and in the highly metastatic mouse mammary tumor model 4 T1. The immunosuppressive environment complicates the use of the humoral response against the tumor as an immunodiagnostic tool. IgM has not been used in immunodiagnostic in part because its antitumor responses, both innate and adaptive, have not been studied in function of time in breast cancer. We show a new approach to analyzing the mouse humoral immune response, and compare the evolution with time of IgG and IgM responses against the antigens of 4 T1 cells. Methods The study is based on 2-dimensional immunoblotting detection of antigens from 4 T1 cells by the IgG and IgM antibodies in the serum of female mice injected with 4 T1 cells. Results There was a high variability in the intra-and inter-mouse response. Variability in the IgM response was manifested as a pattern of spots that could become a multibinomial variable of 0 and 1, which could represent a signature of the immune response. Different numbers of spots was found in the IgG and IgM responses from week 1 to 5. On average, the IgM had more but the IgG response decrease with the time. The natural IgM at t = 0 responds stronger than w1; the adaptive response of both IgM and IgG were elicited where, with the former being stronger better than the latter. Antigens that are recognized by some female mice in the first week are also recognized by other female mice at time 0. Contamination of the natural IgM makes difficult use the adaptive IgM as a tool for immunodiagnostic. Conclusions IgM and IgG response varied with the time and individuals. Spot variation in 2D pattern for the natural IgM could be expressed as a binomial signature, which opens up the way to correlate a particular pattern with resistance or susceptibility. This uncovers a battery of IgMs for each individual to confront cancer or infections. The possibility to differentiate between adaptive IgM antibodies

  8. Sex steroid hormones and circulating IgE levels.

    PubMed

    Mathur, S; Mathur, R S; Goust, J M; Williamson, H O; Fudenberg, H H

    1977-12-01

    The possible influence of sex steroid hormones on circulating IgE levels in general and IgE anti-Candida antibodies in particular was studied by quantification of plasma levels of progesterone, estradiol and IgE (total and anti-Candida-specific) in females during the follicular and luteal phases of the menstrual cycle, and during pregnancy. IgE levels during the follicular and luteal phases were not significantly different, although the mean values for the luteal phase were slightly lower. This trend was apparent in daily samples from two normal females during one menstrual cycle. During pregnancy, when the levels of circulating sex steroids were high, IgE levels were only slightly higher than in the follicular and luteal phases. In men and in gonadal dysgenetics, circulating progesterone levels were similar to those of women during the follicular phase (i.e., lower than in the luteal phase or in pregnancy), but the IgE levels were not different. The apparently low levels of IgE during the luteal phase may therefore be due to physiological factors other than fluctuations in the sex steroid hormones. From the present studies, it is apparent that sex steroid hormones have little or no effect on humoral IgE levels, in marked contrast to previously described correlations for other immunoglobulins, especially anti-Candida antibodies.

  9. IGS Network Coordinator Report - 2002

    NASA Technical Reports Server (NTRS)

    Moore, Angelyn

    2004-01-01

    The IGS network is a set of permanent, continuously-operating, dual-frequency GPS stations operated by over 100 worldwide agencies. The dataset is pooled at IGS Data Centers for routine use by IGS Analysis Centers in creating precise IGS products, as well as free access by other analysts around the world. The IGS Central Bureau hosts the IGS Network Coordinator, who assures adherence to standards and provides information regarding the IGS network via the Central Bureau Information System website at http://igscb.jpl.nasa.gov.

  10. Predator-prey body size relationships when predators can consume prey larger than themselves.

    PubMed

    Nakazawa, Takefumi; Ohba, Shin-Ya; Ushio, Masayuki

    2013-06-23

    As predator-prey interactions are inherently size-dependent, predator and prey body sizes are key to understanding their feeding relationships. To describe predator-prey size relationships (PPSRs) when predators can consume prey larger than themselves, we conducted field observations targeting three aquatic hemipteran bugs, and assessed their body masses and those of their prey for each hunting event. The data revealed that their PPSR varied with predator size and species identity, although the use of the averaged sizes masked these effects. Specifically, two predators had slightly decreased predator-prey mass ratios (PPMRs) during growth, whereas the other predator specialized on particular sizes of prey, thereby showing a clear positive size-PPMR relationship. We discussed how these patterns could be different from fish predators swallowing smaller prey whole.

  11. Coevolution can reverse predator-prey cycles.

    PubMed

    Cortez, Michael H; Weitz, Joshua S

    2014-05-20

    A hallmark of Lotka-Volterra models, and other ecological models of predator-prey interactions, is that in predator-prey cycles, peaks in prey abundance precede peaks in predator abundance. Such models typically assume that species life history traits are fixed over ecologically relevant time scales. However, the coevolution of predator and prey traits has been shown to alter the community dynamics of natural systems, leading to novel dynamics including antiphase and cryptic cycles. Here, using an eco-coevolutionary model, we show that predator-prey coevolution can also drive population cycles where the opposite of canonical Lotka-Volterra oscillations occurs: predator peaks precede prey peaks. These reversed cycles arise when selection favors extreme phenotypes, predator offense is costly, and prey defense is effective against low-offense predators. We present multiple datasets from phage-cholera, mink-muskrat, and gyrfalcon-rock ptarmigan systems that exhibit reversed-peak ordering. Our results suggest that such cycles are a potential signature of predator-prey coevolution and reveal unique ways in which predator-prey coevolution can shape, and possibly reverse, community dynamics.

  12. Campylobacter spp. and birds of prey.

    PubMed

    Dipineto, Ludovico; De Luca Bossa, Luigi Maria; Russo, Tamara Pasqualina; Cutino, Eridania Annalisa; Gargiulo, Antonio; Ciccarelli, Francesca; Raia, Pasquale; Menna, Lucia Francesca; Fioretti, Alessandro

    2014-06-01

    A total of 170 birds of prey admitted to two Wildlife Rescue and Rehabilitation Centers of Italy were examined. Birds were divided by diurnal (n = 15) and nocturnal (n = 7) species, sampled by cloacal swabs, and examined for Campylobacter spp. by cultural and molecular methods. Campylobacter spp. were isolated in 43 out of the 170 (25.3%) birds of prey examined. Among these, 43/43 (100%) were identified as Campylobacter jejuni and 10/43 (23.3%) were identified as Campylobacter coli recovered from mixed infections. Diurnal birds of prey showed a significantly higher prevalence value (P = 0.0006) for Campylobacter spp. than did nocturnal birds of prey.

  13. Theory of Arachnid Prey Localization

    NASA Astrophysics Data System (ADS)

    Stürzl, W.; Kempter, R.; van Hemmen, J. L.

    2000-06-01

    Sand scorpions and many other arachnids locate their prey through highly sensitive slit sensilla at the tips (tarsi) of their eight legs. This sensor array responds to vibrations with stimulus-locked action potentials encoding the target direction. We present a neuronal model to account for stimulus angle determination using a population of second-order neurons, each receiving excitatory input from one tarsus and inhibition from a triad opposite to it. The input opens a time window whose width determines a neuron's firing probability. Stochastic optimization is realized through tuning the balance between excitation and inhibition. The agreement with experiments on the sand scorpion is excellent.

  14. Prey Carrying Capacity Modulates the Effect of Predation on Prey Diversity.

    PubMed

    Socolar, Jacob; Washburne, Alex

    2015-09-01

    Understanding the role of predation in regulating prey diversity is a major goal in ecology, with profound consequences for community dynamics, ecosystem structure, and conservation practice. Deterministic differential equation models predict that some predation regimes, such as prey-switching predation, should promote prey coexistence and increase prey diversity. However, such models do not capture stochastic population fluctuations that are ubiquitous in empirical study sites and nature reserves. In this article, we examine the effects of prey-switching predation on the species richness of prey communities with demographic noise. We show that in finite, discrete prey populations, the ability of prey-switching predation to promote diversity depends on the carrying capacity of the prey community and the richness of the source pool for prey. Identical predation regimes may have opposite effects on prey diversity depending on the size and productivity of the habitat or the metacommunity richness. Statistical properties of the fluctuations of prey populations determine the effect of stabilizing mechanisms on species richness. We discuss the implications of this result for empirical studies of predation in small study areas and for the management of small nature reserves.

  15. "Prey Play": Learning about Predators and Prey through an Interactive, Role-Play Game

    ERIC Educational Resources Information Center

    Deaton, Cynthia C. M.; Dodd, Kristen; Drennon, Katherine; Nagle, Jack

    2012-01-01

    "Prey Play" is an interactive role-play activity that provides fifth-grade students with opportunities to examine predator-prey interactions. This four-part, role-play activity allows students to take on the role of a predator and prey as they reflect on the behaviors animals exhibit as they collect food and interact with one another, as well as…

  16. Controllability and Optimal Harvesting of a Prey-Predator Model Incorporating a Prey Refuge

    ERIC Educational Resources Information Center

    Kar, Tapan Kumar

    2006-01-01

    This paper deals with a prey-predator model incorporating a prey refuge and harvesting of the predator species. A mathematical analysis shows that prey refuge plays a crucial role for the survival of the species and that the harvesting effort on the predator may be used as a control to prevent the cyclic behaviour of the system. The optimal…

  17. Deterministic and Stochastic Analysis of a Prey-Dependent Predator-Prey System

    ERIC Educational Resources Information Center

    Maiti, Alakes; Samanta, G. P.

    2005-01-01

    This paper reports on studies of the deterministic and stochastic behaviours of a predator-prey system with prey-dependent response function. The first part of the paper deals with the deterministic analysis of uniform boundedness, permanence, stability and bifurcation. In the second part the reproductive and mortality factors of the prey and…

  18. IgG4-Related Disease Presenting as Isolated Scleritis

    PubMed Central

    Arnon, Ella; Yaakobi, Alona; Cohen, Yuval; Tiosano, Beatrice

    2017-01-01

    A rare case of IgG4-related disease (IgG4-RD) manifesting as nodular scleritis is presented in a 20-year-old female. Patient complained of left eye pain and redness for one week. Ocular examination together with ancillary testing led to the diagnosis of nodular scleritis. Since the patient did not show apparent improvement after one week of systemic steroidal treatment, she underwent a biopsy of the affected area revealing histopathological characteristics of IgG4-RD. Long-term treatment with corticosteroids and a steroid-sparing agent (methotrexate) led to significant improvement in signs and symptoms. This case highlights the significance of IgG4-RD in the differential diagnosis of scleritis and raises the question as to whether various organs affected by IgG4-RD may have different underlying pathophysiological mechanisms in which pathogenic T cells play a role. PMID:28149653

  19. Canine IgA nephropathy: a case report.

    PubMed

    Yabuki, Akira; Shimokawa Miyama, Takako; Kohyama, Moeko; Yamato, Osamu

    2016-03-01

    Immunoglobulin (Ig) A nephropathy is a rare form of canine glomerular disease. This report describes a case of canine IgA nephropathy showing characteristics typical of human IgA nephropathy. An 8-year-old, spayed female Miniature Dachshund showed persistent severe proteinuria without azotemia. She was receiving long-term glucocorticoid therapy due to chronic gastritis and an intra-abdominal suture granuloma. A renal biopsy demonstrated mesangial proliferative glomerulonephritis with predominantly mesangial IgA deposition and electron-dense deposits in the paramesangium. These findings closely resembled those of human IgA nephropathy. Glucocorticoid treatment was discontinued, and the angiotensin-converting enzyme inhibitor enalapril was administrated as an antiproteinuric agent. The proteinuria subsequently went into remission, and the patient has maintained good condition without recurrence.

  20. IGS Data Flow

    NASA Technical Reports Server (NTRS)

    Noll, Carey

    2006-01-01

    The IGS analysis centers and user community in general need to be assured that the data centers archive a consistent set of files. Changes to the archives can occur because of the re-publishing of data, the transmission of historic data, and the resulting re-distribution (or lack thereof) of these data from data center to data center. To ensure the quality of the archives, a defined data flow and method of archive population needs to be established. This poster will diagram and review the current IGS data flow, discuss problems that have occurred, and provide recommendations for improvement.

  1. Australian Fur Seals (Arctocephalus pusillus doriferus) Use Raptorial Biting and Suction Feeding When Targeting Prey in Different Foraging Scenarios

    PubMed Central

    Hocking, David P.; Salverson, Marcia; Fitzgerald, Erich M. G.; Evans, Alistair R.

    2014-01-01

    Foraging behaviours used by two female Australian fur seals (Arctocephalus pusillus doriferus) were documented during controlled feeding trials. During these trials the seals were presented with prey either free-floating in open water or concealed within a mobile ball or a static box feeding device. When targeting free-floating prey both subjects primarily used raptorial biting in combination with suction, which was used to draw prey to within range of the teeth. When targeting prey concealed within either the mobile or static feeding device, the seals were able to use suction to draw out prey items that could not be reached by biting. Suction was followed by lateral water expulsion, where water drawn into the mouth along with the prey item was purged via the sides of the mouth. Vibrissae were used to explore the surface of the feeding devices, especially when locating the openings in which the prey items had been hidden. The mobile ball device was also manipulated by pushing it with the muzzle to knock out concealed prey, which was not possible when using the static feeding device. To knock prey out of this static device one seal used targeted bubble blowing, where a focused stream of bubbles was blown out of the nose into the openings in the device. Once captured in the jaws, prey items were manipulated and re-oriented using further mouth movements or chews so that they could be swallowed head first. While most items were swallowed whole underwater, some were instead taken to the surface and held in the teeth, while being vigorously shaken to break them into smaller pieces before swallowing. The behavioural flexibility displayed by Australian fur seals likely assists in capturing and consuming the extremely wide range of prey types that are targeted in the wild, during both benthic and epipelagic foraging. PMID:25390347

  2. Life-History Traits of Macrolophus pygmaeus with Different Prey Foods

    PubMed Central

    Sylla, Serigne; Brévault, Thierry; Diarra, Karamoko; Bearez, Philippe; Desneux, Nicolas

    2016-01-01

    Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a generalist predatory mirid widely used in augmentative biological control of various insect pests in greenhouse tomato production in Europe, including the invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). However, its biocontrol efficacy often relies on the presence of alternative prey. The present study aimed at evaluating the effect of various prey foods (Ephestia kuehniella eggs, Bemisia tabaci nymphs, Tuta absoluta eggs and Macrosiphum euphorbiae nymphs) on some life history traits of M. pygmaeus. Both nymphal development and adult fertility of M. pygmaeus were significantly affected by prey food type, but not survival. Duration of nymphal stage was higher when M. pygmaeus fed on T. absoluta eggs compared to the other prey. Mean fertility of M. pygmaeus females was greatest when fed with B. tabaci nymphs, and was greater when offered M. euphorbiae aphids and E. kuehniella eggs than when offered T. absoluta eggs. Given the low quality of T. absoluta eggs, the efficacy of M. pygmaeus to control T. absoluta may be limited in the absence of other food sources. Experiments for assessing effectiveness of generalist predators should involve the possible impact of prey preference as well as a possible prey switching. PMID:27870857

  3. Inducible defenses in prey intensify predator cannibalism.

    PubMed

    Kishida, Osamu; Trussell, Geoffrey C; Nishimura, Kinya; Ohgushi, Takayuki

    2009-11-01

    Trophic cascades are often a potent force in ecological communities, but abiotic and biotic heterogeneity can diffuse their influence. For example, inducible defenses in many species create variation in prey edibility, and size-structured interactions, such as cannibalism, can shift predator diets away from heterospecific prey. Although both factors diffuse cascade strength by adding heterogeneity to trophic interactions, the consequences of their interactioh remain poorly understood. We show that inducible defenses in tadpole prey greatly intensify cannibalism in predatory larval salamanders. The likelihood of cannibalism was also strongly influenced by asymmetries in salamander size that appear to be most important in the presence of defended prey. Hence, variation in prey edibility and the size structure of the predator may synergistically affect predator-prey population dynamics by reducing prey mortality and increasing predator mortality via cannibalism. We also suggest that the indirect effects of prey defenses may shape the evolution of predator traits that determine diet breadth and how trophic dynamics unfold in natural systems.

  4. IgA nephropathy enigma.

    PubMed

    Mestecky, Jiri; Novak, Jan; Moldoveanu, Zina; Raska, Milan

    2016-11-01

    IgA nephropathy (IgAN) is the leading cause of primary glomerulonephritis in the world. The disease is characterized by the presence of IgA-containing immune complexes in the circulation and in mesangial deposits with ensuing glomerular injury. Although in humans there are two IgA subclasses, only IgA1 molecules are involved. The exclusivity of participation of IgA1 in IgAN prompted extensive structural and immunological studies of the unique hinge region (HR) of IgA1, which is absent in otherwise highly homologous IgA2. HR of IgA1 with altered O-glycans serves as an antigen recognized by autoantibodies specific for aberrant HR glycans leading to the generation of nephritogenic immune complexes. However, there are several unresolved questions concerning the phylogenetic origin of human IgA1 HR, the structural basis of its antigenicity, the origin of antibodies specific for HR with altered glycan moieties, the regulatory defects in IgA1 glycosylation pathways, and the potential approaches applicable to the disease-specific interventions in the formation of nephritogenic immune complexes. This review focuses on the gaps in our knowledge of molecular and cellular events that are involved in the immunopathogenesis of IgAN.

  5. Adaptation of prey and predators between patches.

    PubMed

    Wang, Wendi; Takeuchi, Yasuhiro

    2009-06-21

    Mathematical models are proposed to simulate migrations of prey and predators between patches. In the absence of predators, it is shown that the adaptation of prey leads to an ideal spatial distribution in the sense that the maximal capacity of each patch is achieved. With the introduction of co-adaptation of predators, it is proved that both prey and predators achieve ideal spatial distributions when the adaptations are weak. Further, it is shown that the adaptation of prey and predators increases the survival probability of predators from the extinction in both patches to the persistence in one patch. It is also demonstrated that there exists a pattern that prey and predators cooperate well through adaptations such that predators are permanent in every patch in the case that predators become extinct in each patch in the absence of adaptations. For strong adaptations, it is proved that the model admits periodic cycles and multiple stability transitions.

  6. Prey-mediated effects of the protease inhibitor aprotinin on the predatory carabid beetle Nebria brevicollis.

    PubMed

    Burgess, E P.J.; Lövei, G L.; Malone, L A.; Nielsen, I W.; Gatehouse, H S.; Christeller, J T.

    2002-12-01

    To investigate the potential non-target impacts of transgenic pest-resistant plants, prey-mediated impacts of a protease inhibitor (PI) on the predatory carabid, Nebria brevicollis, were investigated. The PI used was aprotinin, a serine PI of mammalian origin with insecticidal properties when incorporated in artificial diet or expressed in transgenic plants. Field-collected N. brevicollis adults, kept at 23 degrees C, 16:8 L:D, were fed, over their pre-aestivation activity period of 24 days, with Helicoverpa armigera larvae reared on an artificial diet containing 0.5% (w:w, fresh mass) aprotinin. These larvae contained 22.62 &mgr;g aprotinin/g insect. Control prey was reared on diet without aprotinin. Beetle survival and body mass were unaffected by prey type. Beetles consuming PI-fed prey lost significantly more mass than the control beetles during two periods of mass loss, but gained significantly more mass during the final period of mass gain. This was not due to differences in amounts of prey supplied or consumed. The final mass gain coincided with increased consumption of PI-prey. Female beetles were significantly heavier than males, but we found no consistent gender-based differences in response to PI-prey. At the end of the experiment, body mass of all beetles was similar to field-collected ones (approximately 55 mg). All experimental beetles had significantly lower activities of digestive cysteine proteases and the serine proteases chymotrypsin and trypsin than field-collected ones. Beetles consuming PI-fed prey had significantly lower levels of trypsin and higher levels of chymotrypsin and elastase than the control beetles.

  7. Increased autumn rainfall disrupts predator-prey interactions in fragmented boreal forests.

    PubMed

    Terraube, Julien; Villers, Alexandre; Poudré, Léo; Varjonen, Rauno; Korpimäki, Erkki

    2016-07-02

    There is a pressing need to understand how changing climate interacts with land-use change to affect predator-prey interactions in fragmented landscapes. This is particularly true in boreal ecosystems facing fast climate change and intensification in forestry practices. Here, we investigated the relative influence of autumn climate and habitat quality on the food-storing behaviour of a generalist predator, the pygmy owl, using a unique data set of 15 850 prey items recorded in western Finland over 12 years. Our results highlighted strong effects of autumn climate (number of days with rainfall and with temperature <0 °C) on food-store composition. Increasing frequency of days with precipitation in autumn triggered a decrease in (i) total prey biomass stored, (ii) the number of bank voles (main prey) stored, and (iii) the scaled mass index of pygmy owls. Increasing proportions of old spruce forests strengthened the functional response of owls to variations in vole abundance and were more prone to switch from main prey to alternative prey (passerine birds) depending on local climate conditions. High-quality habitat may allow pygmy owls to buffer negative effects of inclement weather and cyclic variation in vole abundance. Additionally, our results evidenced sex-specific trends in body condition, as the scaled mass index of smaller males increased while the scaled mass index of larger females decreased over the study period, probably due to sex-specific foraging strategies and energy requirements. Long-term temporal stability in local vole abundance refutes the hypothesis of climate-driven change in vole abundance and suggests that rainier autumns could reduce the vulnerability of small mammals to predation by pygmy owls. As small rodents are key prey species for many predators in northern ecosystems, our findings raise concern about the impact of global change on boreal food webs through changes in main prey vulnerability.

  8. Predators target rare prey in coral reef fish assemblages.

    PubMed

    Almany, Glenn R; Peacock, Lisa F; Syms, Craig; McCormick, Mark I; Jones, Geoffrey P

    2007-07-01

    Predation can result in differing patterns of local prey diversity depending on whether predators are selective and, if so, how they select prey. A recent study comparing the diversity of juvenile fish assemblages among coral reefs with and without predators concluded that decreased prey diversity in the presence of predators was most likely caused by predators actively selecting rare prey species. We used several related laboratory experiments to explore this hypothesis by testing: (1) whether predators prefer particular prey species, (2) whether individual predators consistently select the same prey species, (3) whether predators target rare prey, and (4) whether rare prey are more vulnerable to predation because they differ in appearance/colouration from common prey. Rare prey suffered greater predation than expected and were not more vulnerable to predators because their appearance/colouration differed from common prey. Individual predators did not consistently select the same prey species through time, suggesting that prey selection behaviour was flexible and context dependent rather than fixed. Thus, selection of rare prey was unlikely to be explained by simple preferences for particular prey species. We hypothesize that when faced with multiple prey species predators may initially focus on rare, conspicuous species to overcome the sensory confusion experienced when attacking aggregated prey, thereby minimizing the time required to capture prey. This hypothesis represents a community-level manifestation of two well-documented and related phenomena, the "confusion effect" and the "oddity effect", and may be an important, and often overlooked, mechanism by which predators influence local species diversity.

  9. Serum Galactose-Deficient IgA1 Level Is Not Associated with Proteinuria in Children with IgA Nephropathy

    PubMed Central

    Hastings, M. Colleen; Afshan, Sabahat; Sanders, John T.; Kane, Oulimata; Eison, T. Matthew; Lau, Keith K.; Moldoveanu, Zina; Julian, Bruce A.; Novak, Jan; Wyatt, Robert J.

    2012-01-01

    Introduction. Percentage of galactose-deficient IgA1 (Gd-IgA1) relative to total IgA in serum was recently reported to correlate with proteinuria at time of sampling and during follow-up for pediatric and adult patients with IgA nephropathy. We sought to determine whether this association exists in another cohort of pediatric patients with IgA nephropathy. Methods. Subjects were younger than 18 years at entry. Blood samples were collected on one or more occasions for determination of serum total IgA and Gd-IgA1. Gd-IgA1 was expressed as serum level and percent of total IgA. Urinary protein/creatinine ratio was calculated for random specimens. Spearman's correlation coefficients assessed the relationship between study variables. Results. The cohort had 29 Caucasians and 11 African-Americans with a male : female ratio of 1.9 : 1. Mean age at diagnosis was 11.7 ± 3.7 years. No statistically significant correlation was identified between serum total IgA, Gd-IgA1, or percent Gd-IgA1 versus urinary protein/creatinine ratio determined contemporaneously with biopsy or between average serum Gd-IgA1 or average percent Gd-IgA1 and time-average urinary protein/creatinine ratio. Conclusion. The magnitude of proteinuria in this cohort of pediatric patients with IgA nephropathy was influenced by factors other than Gd-IgA1 level, consistent with the proposed multi-hit pathogenetic pathways for this renal disease. PMID:22754697

  10. IgG deposition in IgA nephropathy patients.

    PubMed

    Nasri, Hamid

    2013-01-01

    IgA nephropathy is the most common form of glomerular disease among young adults. The aim of this study is to determine the correlation of IgG deposition with morphologic variables of Oxford classification and some clinical data of patients with IgA nephropathy (IgAN).A total of 114 biopsies were enrolled to the study (70.2% were male). Mean age of the patients was 37.7±13.6 years. This study showed that, IgG deposition intensity had not significant correlation with serum creatinine. No significant association of sex with IgG was found. There was not significant association of IgG deposits with age below and more that 40 years. There was not significant association of IgG deposit intensity with four morphologic variables of Oxford classification. Less studied published regarding the immunostaining findings in IgA nephropathy patients. Location of deposited immunoglobulin (mesangial versus mesangial-capillary) or the type of immunoglobulin (IgG or IgM) may have prognostic significant. More studies needs to find the clinical significance of immunostaining data.

  11. The effect of habitat structure on prey mortality depends on predator and prey microhabitat use.

    PubMed

    Klecka, Jan; Boukal, David S

    2014-09-01

    Structurally complex habitats provide cover and may hinder the movement of animals. In predator-prey relationships, habitat structure can decrease predation risk when it provides refuges for prey or hinders foraging activity of predators. However, it may also provide shelter, supporting structures and perches for sit-and-wait predators and hence increase their predation rates. We tested the effect of habitat structure on prey mortality in aquatic invertebrates in short-term laboratory predation trials that differed in the presence or absence of artificial vegetation. The effect of habitat structure on prey mortality was context dependent as it changed with predator and prey microhabitat use. Specifically, we observed an 'anti-refuge' effect of added vegetation: phytophilous predators that perched on the plants imposed higher predation pressure on planktonic prey, while mortality of benthic prey decreased. Predation by benthic and planktonic predators on either type of prey remained unaffected by the presence of vegetation. Our results show that the effects of habitat structure on predator-prey interactions are more complex than simply providing prey refuges or cover for predators. Such context-specific effects of habitat complexity may alter the coupling of different parts of the ecosystem, such as pelagic and benthic habitats, and ultimately affect food web stability through cascading effects on individual life histories and trophic link strengths.

  12. Prey vulnerability to peacock cichlids and largemouth bass based on predator gape and prey body depth

    USGS Publications Warehouse

    Hill, Jeffrey E.; Nico, Leo G.; Cichra, Charles E.; Gilbert, Carter R.

    2005-01-01

    The interaction of prey fish body depth and predator gape size may produce prey assemblages dominated by invulnerable prey and excessive prey-to-predator biomass ratios. Peacock cichlids (Cichla ocellaris) were stocked into southeast Florida canals to consume excess prey fish biomass, particularly spotted tilapia (Tilapia mariae). The ecomorphologically similar largemouth bass (Micropterus salmoides) was already present in the canals. We present relations of length-specific gape size for peacock cichlids and largemouth bass. Both predators have broadly overlapping gape size, but largemouth bass ?126 mm total length have slightly larger gape sizes than peacock cichlids of the same length. Also, we experimentally tested the predictions of maximum prey size for peacock cichlids and determined that a simple method of measuring gape size used for largemouth bass also is appropriate for peacock cichlids. Lastly, we determined relations of body depth and length of prey species to investigate relative vulnerability. Using a simple predator-prey model and length frequencies of predators and bluegill (Lepomis macrochirus), redear sunfish (Lepomis microlophus), and spotted tilapia prey, we documented that much of the prey biomass in southeast Florida canals is unavailable for largemouth bass and peacock cichlid predation.

  13. Fluorescent prey traps in carnivorous plants.

    PubMed

    Kurup, R; Johnson, A J; Sankar, S; Hussain, A A; Sathish Kumar, C; Sabulal, B

    2013-05-01

    Carnivorous plants acquire most of their nutrients by capturing ants, insects and other arthropods through their leaf-evolved biological traps. So far, the best-known attractants in carnivorous prey traps are nectar, colour and olfactory cues. Here, fresh prey traps of 14 Nepenthes, five Sarracenia, five Drosera, two Pinguicula species/hybrids, Dionaea muscipula and Utricularia stellaris were scanned at UV 366 nm. Fluorescence emissions of major isolates of fresh Nepenthes khasiana pitcher peristomes were recorded at an excitation wavelength of 366 nm. N. khasiana field pitcher peristomes were masked by its slippery zone extract, and prey capture rates were compared with control pitchers. We found the existence of distinct blue fluorescence emissions at the capture spots of Nepenthes, Sarracenia and Dionaea prey traps at UV 366 nm. These alluring blue emissions gradually developed with the growth of the prey traps and diminished towards their death. On excitation at 366 nm, N. khasiana peristome 3:1 CHCl3–MeOH extract and its two major blue bands showed strong fluorescence emissions at 430–480 nm. Masking of blue emissions on peristomes drastically reduced prey capture in N. khasiana pitchers. We propose these molecular emissions as a critical factor attracting arthropods and other visitors to these carnivorous traps. Drosera, Pinguicula and Utricularia prey traps showed only red chlorophyll emissions at 366 nm.

  14. Disentangling taste and toxicity in aposematic prey.

    PubMed

    Holen, Øistein Haugsten

    2013-02-22

    Many predators quickly learn to avoid attacking aposematic prey. If the prey vary in toxicity, the predators may alternatively learn to capture and taste-sample prey carefully before ingesting or rejecting them (go-slow behaviour). An increase in prey toxicity is generally thought to decrease predation on prey populations. However, while prey with a higher toxin load are more harmful to ingest, they may also be easier to recognize and reject owing to greater distastefulness, which can facilitate a taste-sampling foraging strategy. Here, the classic diet model is used to study the separate effects of taste and toxicity on predator preferences. The taste-sampling process is modelled using signal detection theory. The model is applicable to automimicry and batesian mimicry. It shows that when the defensive toxin is sufficiently distasteful, a mimicry complex may be less profitable to the predator and better protected against predation if the models are moderately toxic than if they are highly toxic. Moreover, taste mimicry can reduce the profitability of the mimicry complex and increase protection against predation. The results are discussed in relation to the selection pressures acting on prey defences and the evolution of mimicry.

  15. Disentangling taste and toxicity in aposematic prey

    PubMed Central

    Holen, Øistein Haugsten

    2013-01-01

    Many predators quickly learn to avoid attacking aposematic prey. If the prey vary in toxicity, the predators may alternatively learn to capture and taste-sample prey carefully before ingesting or rejecting them (go-slow behaviour). An increase in prey toxicity is generally thought to decrease predation on prey populations. However, while prey with a higher toxin load are more harmful to ingest, they may also be easier to recognize and reject owing to greater distastefulness, which can facilitate a taste-sampling foraging strategy. Here, the classic diet model is used to study the separate effects of taste and toxicity on predator preferences. The taste-sampling process is modelled using signal detection theory. The model is applicable to automimicry and Batesian mimicry. It shows that when the defensive toxin is sufficiently distasteful, a mimicry complex may be less profitable to the predator and better protected against predation if the models are moderately toxic than if they are highly toxic. Moreover, taste mimicry can reduce the profitability of the mimicry complex and increase protection against predation. The results are discussed in relation to the selection pressures acting on prey defences and the evolution of mimicry. PMID:23256198

  16. Problems with studying wolf predation on small prey in summer via global positioning system collars

    USGS Publications Warehouse

    Palacios, Vicente; Mech, L. David

    2010-01-01

    We attempted to study predation on various-sized prey by a male and female wolf (Canis lupus) with global positioning system (GPS) collars programmed to acquire locations every 10 min in the Superior National Forest of Minnesota. During May to August 2007, we investigated 147 clusters of locations (31% of the total) and found evidence of predation on a white-tailed deer (Odocoileus virginianus) fawn and yearling, a beaver (Castor canadensis), ruffed grouse (Bonasa umbellus), and fisher (Martes pennanti) and scavenging on a road-killed deer and other carrion. However, we missed finding many prey items and discuss the problems associated with trying to conduct such a study.

  17. Microbiological survey of birds of prey pellets.

    PubMed

    Dipineto, Ludovico; Bossa, Luigi Maria De Luca; Pace, Antonino; Russo, Tamara Pasqualina; Gargiulo, Antonio; Ciccarelli, Francesca; Raia, Pasquale; Caputo, Vincenzo; Fioretti, Alessandro

    2015-08-01

    A microbiological survey of 73 pellets collected from different birds of prey species housed at the Wildlife Rescue and Rehabilitation Center of Napoli (southern Italy) was performed. Pellets were analyzed by culture and biochemical methods as well as by serotyping and polymerase chain reaction. We isolated a wide range of bacteria some of them also pathogens for humans (i.e. Salmonella enterica serotype Typhimurium, Campylobacter coli, Escherichia coli O serogroups). This study highlights the potential role of birds of prey as asymptomatic carriers of pathogenic bacteria which could be disseminated in the environment not only through the birds of prey feces but also through their pellets.

  18. Ecoepidemics with Two Strains: Diseased Prey.

    NASA Astrophysics Data System (ADS)

    Elena, Elisa; Grammauro, Maria; Venturino, Ezio

    2011-09-01

    In this work we present a minimal model for an ecoepidemic situation with two diseases affecting the prey population. The main assumptions are the following ones. The predators recognize and hunt only the healthy prey. An infected prey of one strain becomes immune to the other one. The major finding shows that the two strains cannot simultaneously thrive in the system, contrary to the standard assumptions in epidemiology. But this rather unexpected and remarkable result, paralleling another one when the epidemics affects the predators, is most likely due to the assumptions made.

  19. Localized linear IgA/IgG bullous dermatosis.

    PubMed

    Shimizu, Satoko; Natsuga, Ken; Shinkuma, Satoru; Yasui, Chikako; Tsuchiya, Kikuo; Shimizu, Hiroshi

    2010-11-01

    Linear IgA/IgG bullous dermatosis (LAGBD) is an auto-immune blistering disease characterized by the local accumulation of IgA- and IgG-class anti-basement membrane autoantibodies. It typically presents as a generalized pruritic vesiculobullous eruption. No cases of localized LAGBD have yet been reported. We report a case of a 78-year-old man with LAGBD localized to the perianal area. The patient complained of suffering from persistent ulcers around the anus for more than 3 years. Physical examination revealed several blisters and ulcers up to 2-cm in diameter around the anus. No lesions were found elsewhere on the body. Histological analysis of a skin biopsy revealed subepidermal blistering, while direct immunofluorescence showed the linear deposition of IgA and IgG antibodies at the dermoepidermal junction. Indirect immunofluorescence of normal human skin whose layers had been separated using 1M NaCl showed the binding of both IgA and IgG to the epidermal side. Immunoblotting demonstrated the presence of circulating IgA and IgG autoantibodies that bound to a 120-kDa protein. This is the first case of localized LAGBD whose skin lesions were restricted to the perianal region.

  20. Signal evolution in prey recognition systems.

    PubMed

    Pie, Marcio R

    2005-01-31

    In this paper a graphical model first developed in the context of kin recognition is adapted to the study of signalling in predator-prey systems. Antipredation strategies are envisioned as points along a signal-to-noise (S/N) axis, with concealing (low S/N) and conspicuous (high S/N) strategies being placed at opposite sides of this axis. Optimal prey recognition systems should find a trade-off between acceptance errors (going after a background cue as if it were a prey) and rejection errors (not going after a prey as if it were background noise). The model also predicts the types of cues the predator should use in opposite sides of the S/N axis.

  1. Jaw and hyolingual movements during prey transport in varanid lizards: effects of prey type.

    PubMed

    Schaerlaeken, Vicky; Montuelle, Stéphane J; Aerts, Peter; Herrel, Anthony

    2011-06-01

    The ability to modulate feeding kinematics in response to prey items with different functional properties is likely a prerequisite for most organisms that feed on a variety of food items. Variation in prey properties is expected to reveal variation in feeding function and the functional role of the different phases in a transport cycle. Here we describe the kinematics of prey transport of two varanid species, Varanus niloticus and Varanus ornatus. These species were selected for analysis because of their highly specialised hyolingual system and food transport mechanism (inertial food transport). In these animals, tongue and hyoid movements are expected to make no, or only a minor, contribution to prey transport. We observed statistically significant prey type effects that could be associated with prey properties such as mass, size and mobility. These data show that both species are capable of modulating the kinematics of food transport in response to different prey types. Moreover, not only the kinematics of the jaws were modulated in response to prey characteristics but also the anterior/posterior movements of the tongue and hyoid. This suggests a more important role of the tongue and hyolingual movements in these animals than previously suspected. In contrast, head movements were rather stereotyped and were not modulated in response to changes in prey type.

  2. A learning strategy for predator preying on edible and inedible prey.

    PubMed

    Tsoularis, A

    2007-01-01

    In this paper I propose a reinforcement learning model for a predator preying upon two types of prey, the unpalatable (noxious) models, and the palatable mimics. The latter type of prey resembles the models in appearance so as to derive some protection from the predator who must avoid the unpalatable models. Essentially the predator is treated as a learning automaton adopting a simple reinforcement learning strategy in order to increase its consumption of palatable prey and reduce the consumption of unpalatable ones. The populations of both mimics and models are assumed to grow logistically.

  3. Effects of the prey refuge distribution on a predator-prey system

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee; Kwon, Ohsung; Song, Hark-Soo

    2016-03-01

    The existence of prey refuges in a predator-prey system is known to be strongly related to the ecosystem's stability. In this study, we explored how the prey refuge distribution affects the predator-prey system. To do so, we constructed a spatial lattice model to simulate an integrative predator (wolf) - prey (rabbit) - plant (grass) relationship. When a wolf (rabbit) encountered a rabbit (grass), the wolf (rabbit) tended to move to the rabbit (grass) for foraging while the rabbit tended to escape from the wolf. These behaviors were mathematically described by the degrees of willingness for hunting ( H) and escaping ( E). Initially, n refuges for prey were heterogeneously distributed in the lattice space. The heterogeneity was characterized as variable A. Higher values of A equate to higher aggregation in the refuge. We investigated the mean population density for different values of H, E, and A. To simply characterize the refuge distribution effect, we built an H-E grid map containing the population density for each species. Then, we counted the number of grids, N, with a population density ≥ 0.25. Simulation results showed that an appropriate value of A positively affected prey survival while values of A were too high had a negative effect on prey survival. The results were explained by using the trade-off between the staying time of the prey in the refuge and the cluster size of the refuge.

  4. Visual illusions in predator-prey interactions: birds find moving patterned prey harder to catch.

    PubMed

    Hämäläinen, Liisa; Valkonen, Janne; Mappes, Johanna; Rojas, Bibiana

    2015-09-01

    Several antipredator strategies are related to prey colouration. Some colour patterns can create visual illusions during movement (such as motion dazzle), making it difficult for a predator to capture moving prey successfully. Experimental evidence about motion dazzle, however, is still very scarce and comes only from studies using human predators capturing moving prey items in computer games. We tested a motion dazzle effect using for the first time natural predators (wild great tits, Parus major). We used artificial prey items bearing three different colour patterns: uniform brown (control), black with elongated yellow pattern and black with interrupted yellow pattern. The last two resembled colour patterns of the aposematic, polymorphic dart-poison frog Dendrobates tinctorius. We specifically tested whether an elongated colour pattern could create visual illusions when combined with straight movement. Our results, however, do not support this hypothesis. We found no differences in the number of successful attacks towards prey items with different patterns (elongated/interrupted) moving linearly. Nevertheless, both prey types were significantly more difficult to catch compared to the uniform brown prey, indicating that both colour patterns could provide some benefit for a moving individual. Surprisingly, no effect of background (complex vs. plain) was found. This is the first experiment with moving prey showing that some colour patterns can affect avian predators' ability to capture moving prey, but the mechanisms lowering the capture rate are still poorly understood.

  5. Seasonal diet and prey preference of the African lion in a waterhole-driven semi-arid savanna.

    PubMed

    Davidson, Zeke; Valeix, Marion; Van Kesteren, Freya; Loveridge, Andrew J; Hunt, Jane E; Murindagomo, Felix; Macdonald, David W

    2013-01-01

    Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations) of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56%) and female (33%) lions, contributing the most to lion dietary biomass. Jacobs' index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group "medium Bovidae" are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs' index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.

  6. Are lemmings prey or predators?

    NASA Astrophysics Data System (ADS)

    Turchin, P.; Oksanen, L.; Ekerholm, P.; Oksanen, T.; Henttonen, H.

    2000-06-01

    Large oscillations in the populations of Norwegian lemmings have mystified both professional ecologists and lay public. Ecologists suspect that these oscillations are driven by a trophic mechanism: either an interaction between lemmings and their food supply, or an interaction between lemmings and their predators. If lemming cycles are indeed driven by a trophic interaction, can we tell whether lemmings act as the resource (`prey') or the consumer (`predator')? In trophic interaction models, peaks of resource density generally have a blunt, rounded shape, whereas peaks of consumer density are sharp and angular. Here we have applied several statistical tests to three lemming datasets and contrasted them with comparable data for cyclic voles. We find that vole peaks are blunt, consistent with their cycles being driven by the interaction with predators. In contrast, the shape of lemming peaks is consistent with the hypothesis that lemmings are functional predators, that is, their cycles are driven by their interaction with food plants. Our findings suggest that a single mechanism, such as interaction between rodents and predators, is unlikely to provide the `universal' explanation of all cyclic rodent dynamics.

  7. A small subgroup of Hashimoto's thyroiditis is associated with IgG4-related disease.

    PubMed

    Jokisch, Friedrich; Kleinlein, Irene; Haller, Bernhard; Seehaus, Tanja; Fuerst, Heinrich; Kremer, Marcus

    2016-03-01

    IgG4-related disease is a newly identified syndrome characterized by high serum IgG4 levels and increased IgG4-positive plasma cells in involved organs. The incidence of IgG4-related thyroiditis in the Caucasian population of Europe is unknown. We investigated formalin-fixed thyroid gland samples of 216 patients (191 Hashimoto's thyroiditis, 5 Riedel's thyroiditis, and 20 goiters, as controls), morphologically, and immunohistochemically. Cases were divided into two groups: IgG4-related Hashimoto's thyroiditis (24 cases) together with Riedel thyroiditis (1 case) and 171 non-IgG4-related thyroiditis. Compared to the non-IgG4-related cases, IgG4-related thyroiditis showed a higher IgG4/IgG ratio (0.6 vs. 0.1, p < 0.0001), a higher median IgG4 count (45.2 vs. 6.2, p < 0.0001), an association with younger age (42.1 vs. 48.1 years, p = 0.036), and a lower female-to-male ratio (11:1 vs. 17.5:1). Fibrous variant of Hashimoto's thyroiditis was diagnosed in 23 of the 24 IgG4-related cases (96 %) and in 13 of 167 (18 %, p > 0.001) non-IgG4-related cases. The single case of IgG4-related Riedel's thyroiditis also showed a higher median IgG4 plasma cell count (56.3 vs. 14.3) and a higher IgG4/IgG ratio (0.5 vs. 0.2) than the four cases of non-IgG4-related Riedel's thyroiditis. Our data suggests the incidence of IgG4-related disease (IgG4-RD) of the thyroid gland in Europe is considerably lower than that observed in other studies. A significant elevation of IgG4-positive plasma cells was only found in a small group of Hashimoto's thyroiditis and then accompanied by intense fibrosis, indicating an association with IgG4-RD. Morphologically, IgG4-RD of the thyroid gland differs from that in other organ systems, exhibiting a dense fibrosis without intense eosinophilia or obliterative phlebitis.

  8. Males choose to keep their heads: Preference for lower risk females in a praying mantid.

    PubMed

    Avigliano, Esteban; Scardamaglia, Romina C; Gabelli, Fabián M; Pompilio, Lorena

    2016-08-01

    Male reproductive success is obviously mate limited, which implies that males should rarely be choosy. One extreme case of a reproductive (or mating) cost is sexual cannibalism. Recent research has proposed that male mantids (Parastagmatoptera tessellata) are choosy and not complicit in cannibalism and that they modify behavior towards females based on the risk imposed by them. Since female cannibalism depends on females' energetic state (i.e. hunger) we investigated whether male mantids are capable of using environmental cues that provide information regarding the energetic state of females to make their mate choices. Under laboratory conditions, males were confronted individually with three options: a female eating a prey, a female without a prey, and a male eating a prey (as a control for the presence of prey). Each subject comprising a choice was harnessed and placed in the corners of a triangular experimental arena at an equidistant distance from the focal male. The prey was a middle size cricket that subjects ate in approximately twenty minutes. The behavior of focal males was recorded for six hours. Females were under the same deprivation regime and, in line with previous studies, consuming one cricket did not significantly increase females' abdomen girth. Male mantids significantly preferred females that were eating a prey. In all cases choices were made after the females consumed the whole prey. This suggests that males did not use the prey as a direct way to avoid being cannibalized by keeping the female busy. The preference for females that had recently fed may have evolved because of the potential reduction in sexual cannibalism.

  9. IGS 1996 Analysis Center Workshop

    NASA Technical Reports Server (NTRS)

    Neilan, R. E. (Editor); VanScoy, P. A. (Editor); Zumberge, J. F. (Editor)

    1996-01-01

    Components of the IGS[International GPS (Global Positioning System) Service for geodynamics], have operated a GPS tracking system for several years. The network now contains more than 100 stations and has produced a combined GPS ephemeris that has become the standard for geodesists and geophysicists worldwide. IGS data and products are freely available to all thanks to the cooperation and participation of all the IGS members. The IGS has initiated development of several new products, and technical issues permitting greater accuracy of IGS products have been identified. The IGS convened a workshop on March 1996 in Silver Spring, Maryland, USA, to coordinate these developments and to examine technical problems and solutions. The following topics were addressed: orbit/clock combination; Earth orientation; antenna calibration; SINEX and densification of the International Terrestrial Reference Frame (ITRF) using the GPS; receiver standards and performance; and atmospheric topics.

  10. Prey dispersal rate affects prey species composition and trait diversity in response to multiple predators in metacommunities.

    PubMed

    Howeth, Jennifer G; Leibold, Mathew A

    2010-09-01

    1. Recent studies indicate that large-scale spatial processes can alter local community structuring mechanisms to determine local and regional assemblages of predators and their prey. In metacommunities, this may occur when the functional diversity represented in the regional predator species pool interacts with the rate of prey dispersal among local communities to affect prey species diversity and trait composition at multiple scales. 2. Here, we test for effects of prey dispersal rate and spatially and temporally heterogeneous predation from functionally dissimilar predators on prey structure in pond mesocosm metacommunities. An experimental metacommunity consisted of three pond mesocosm communities supporting two differentially size-selective invertebrate predators and their zooplankton prey. In each metacommunity, two communities maintained constant predation and supported either Gyrinus sp. (Coleoptera) or Notonecta ungulata (Hemiptera) predators generating a spatial prey refuge while the third community supported alternating predation from Gyrinus sp. and N. ungulata generating a temporal prey refuge. Mesocosm metacommunities were connected at either low (0.7% day(-1)) or high (10% day(-1)) planktonic prey dispersal. The diversity, composition and body size of zooplankton prey were measured at local and regional (metacommunity) scales. 3. Metacommunities experiencing the low prey dispersal rate supported the greatest regional prey species diversity (H') and evenness (J'). Neither dispersal rate nor predation regime affected local prey diversity or evenness. The spatial prey refuge at low dispersal maintained the largest difference in species composition and body size diversity between communities under Gyrinus and Notonecta predation, suggesting that species sorting was operating at the low dispersal rate. There was no effect of dispersal rate on species diversity or body size distribution in the temporal prey refuge. 4. The frequency distribution, but not

  11. Porpoises: From predators to prey

    NASA Astrophysics Data System (ADS)

    Leopold, Mardik F.; Begeman, Lineke; Heße, Eileen; van der Hiele, Jaap; Hiemstra, Sjoukje; Keijl, Guido; Meesters, Erik H.; Mielke, Lara; Verheyen, Dorien; Gröne, Andrea

    2015-03-01

    Along the Dutch shores hundreds of harbour porpoises Phocoena phocoena are stranded each year. A recurrent phenomenon in the Netherlands is a surge of strandings in late winter and early spring of severely mutilated porpoises, that are mostly in good nutritional body condition (thick blubber layer). These mutilated porpoises have parts of the skin and blubber, and sometimes of the muscle tissue missing. By reviewing photographs of stranded animals taken at the stranding sites as well as autopsy results we found 273 mutilated animals from 2005 to 2012. Mutilations could be classified into several categories, but wounds had been mostly inflicted to the sides of these animals, in a zigzag fashion, or to the throat/cheek region. The stomach contents of 31 zigzags, 12 throats/cheeks and 31 control animals that were not mutilated, from the same age and blubber thickness categories were compared; all these animals had stranded between December and April, 2006-2012. The diet of individuals with zigzag lesions to their sides consisted for a large part of gobies, while animals that had wounds at the throat/cheek had been feeding predominately on clupeids. In comparison, animals without mutilations had a more varied diet, including gobies and clupeids, but also a large proportion of sandeels and gadoids. The finding that the type of mutilation corresponds to a certain diet suggests that porpoises that were feeding on different prey, or in different micro-habitats, were hit in different ways. Animals feeding at the sea floor (on gobies) apparently run a risk of being hit from the side, while animals supposedly feeding higher in the water column (on schooling clupeids), were predominantly hit from below, in the throat region. The wider variation in the diets of non-mutilated porpoises is suggestive of them using a larger variety of micro-habitats.

  12. Tennis, incidence of URTI and salivary IgA.

    PubMed

    Novas, A M P; Rowbottom, D G; Jenkins, D G

    2003-04-01

    Tennis played at an elite level requires intensive training characterized by repeated bouts of brief intermittent high intensity exercise over relatively long periods of time (1 - 3 h or more). Competition can place additional stress on players. The purpose of this study was to investigate the temporal association between specific components of tennis training and competition, the incidence of upper respiratory tract infections (URTI), and salivary IgA, in a cohort of seventeen elite female tennis players. Timed, whole unstimulated saliva samples were collected before and after selected 1-h training sessions at 2 weekly intervals, over 12 weeks. Salivary IgA concentration was measured by ELISA and IgA secretion rate calculated (microg IgA x ml -1 x ml saliva x min -1). Players reported URTI symptoms and recorded training and competition in daily logs. Data analysis showed that higher incidence of URTI was significantly associated with increased training duration and load, and competition level, on a weekly basis. Salivary IgA secretion rate (S-IgA) dropped significantly after 1 hour of tennis play. Over the 12-week period, pre-exercise salivary IgA concentration and secretion rate were directly associated with the amount of training undertaken during the previous day and week (p < 0.05). However, the decline in S-IgA after 1 h of intense tennis play was also positively related to the duration and load of training undertaken during the previous day and week (p < 0.05). Although exercise-induced suppression of salivary IgA may be a risk factor, it could not accurately predict the occurrence of URTI in this cohort of athletes.

  13. How the Magnitude of Prey Genetic Variation Alters Predator-Prey Eco-Evolutionary Dynamics.

    PubMed

    Cortez, Michael H

    2016-09-01

    Evolution can alter the stability and dynamics of ecological communities; for example, prey evolution can drive cyclic dynamics in predator-prey systems that are not possible in the absence of evolution. However, it is unclear how the magnitude of additive genetic variation in the evolving species mediates those effects. In this study, I explore how the magnitude of prey additive genetic variation determines what effects prey evolution has on the dynamics and stability of predator-prey systems. I use linear stability analysis to decompose the stability of a general eco-evolutionary predator-prey model into components representing the stabilities of the ecological and evolutionary subsystems as well as the interactions between those subsystems. My results show that with low genetic variation, the cyclic dynamics and stability of the system are determined by the ecological subsystem. With increased genetic variation, disruptive selection always destabilizes stable communities, stabilizing selection can stabilize or destabilize communities, and prey evolution can alter predator-prey phase lags. Stability changes occur approximately when the magnitude of genetic variation balances the (in)stabilities of the ecological and evolutionary subsystems. I discuss the connections between my stability results and prior results from the theory of adaptive dynamics.

  14. Restructuring fundamental predator-prey models by recognising prey-dependent conversion efficiency and mortality rates.

    PubMed

    Li, Jiqiu; Montagnes, David J S

    2015-05-01

    Incorporating protozoa into population models (from simple predator-prey explorations to complex food web simulations) is of conceptual, ecological, and economic importance. From theoretical and empirical perspectives, we expose unappreciated complexity in the traditional predator-prey model structure and provide a parsimonious solution, especially for protistologists. We focus on how prey abundance alters two key components of models: predator conversion efficiency (e, the proportion of prey converted to predator, before mortality loss) and predator mortality (δ, the portion of the population lost though death). Using a well-established model system (Paramecium and Didinium), we collect data to parameterize a range of existing and novel population models that differ in the functional forms of e and δ. We then compare model simulations to an empirically obtained time-series of predator-prey population dynamics. The analysis indicates that prey-dependent e and δ should be considered when structuring population models and that both prey and predator biomass also vary with prey abundance. Both of these impact the ability of the model to predict population dynamics and, therefore, should be included in theoretical model evaluations and assessment of ecosystem dynamics associated with biomass flux.

  15. Predator prey interactions of Procambarus clarkii with aquatic macroinvertebrates in single and multiple prey systems

    NASA Astrophysics Data System (ADS)

    Correia, Alexandra Marçal; Bandeira, Nuno; Anastácio, Pedro Manuel

    2005-11-01

    Understanding the interspecific interactions of Procambarus clarkii with other aquatic macroinvertebrates will help to unveil the mechanisms and processes underlying biological invasiveness. The purpose of this study was to investigate predator-prey interactions of two ontogenic phases of P. clarkii with native and exotic species of aquatic macroinvertebrates at a single and multiple prey level. We performed laboratory experiments to determine the consumption and the behavioral responses of Chironomus riparius, Physa acuta and Corbicula fluminea to P. clarkii. The presence of P. clarkii significantly affected the abundance of C. riparius and P. acuta, but not of C. fluminea whether prey species were provided singly or simultaneously. The consumption of C. riparius by P. clarkii was higher than P. acuta for both crayfish sizes and situations (single/multiple prey systems) and C. fluminea was never consumed. Physa acuta was the only species that exhibited an anti-predator behavior to P. clarkii. Our results show that P. clarkii can have strong consumptive and trait effects on aquatic macroinvertebrate prey at a single and multiple prey level, resulting in differential impacts on different prey species. This study clarifies some aspects of the predator-prey interactions between P. clarkii and native as well as other exotic macroinvertebrate species that have invaded freshwater biocenosis worldwide.

  16. Snow Leopard and Himalayan Wolf: Food Habits and Prey Selection in the Central Himalayas, Nepal

    PubMed Central

    Odden, Morten; Wegge, Per

    2017-01-01

    Top carnivores play an important role in maintaining energy flow and functioning of the ecosystem, and a clear understanding of their diets and foraging strategies is essential for developing effective conservation strategies. In this paper, we compared diets and prey selection of snow leopards and wolves based on analyses of genotyped scats (snow leopards n = 182, wolves n = 57), collected within 26 sampling grid cells (5×5 km) that were distributed across a vast landscape of ca 5000 km2 in the Central Himalayas, Nepal. Within the grid cells, we sampled prey abundances using the double observer method. We found that interspecific differences in diet composition and prey selection reflected their respective habitat preferences, i.e. snow leopards significantly preferred cliff-dwelling wild ungulates (mainly bharal, 57% of identified material in scat samples), whereas wolves preferred typically plain-dwellers (Tibetan gazelle, kiang and argali, 31%). Livestock was consumed less frequently than their proportional availability by both predators (snow leopard = 27%; wolf = 24%), but significant avoidance was only detected among snow leopards. Among livestock species, snow leopards significantly preferred horses and goats, avoided yaks, and used sheep as available. We identified factors influencing diet composition using Generalized Linear Mixed Models. Wolves showed seasonal differences in the occurrence of small mammals/birds, probably due to the winter hibernation of an important prey, marmots. For snow leopard, occurrence of both wild ungulates and livestock in scats depended on sex and latitude. Wild ungulates occurrence increased while livestock decreased from south to north, probably due to a latitudinal gradient in prey availability. Livestock occurred more frequently in scats from male snow leopards (males: 47%, females: 21%), and wild ungulates more frequently in scats from females (males: 48%, females: 70%). The sexual difference agrees with previous

  17. Snow Leopard and Himalayan Wolf: Food Habits and Prey Selection in the Central Himalayas, Nepal.

    PubMed

    Chetri, Madhu; Odden, Morten; Wegge, Per

    2017-01-01

    Top carnivores play an important role in maintaining energy flow and functioning of the ecosystem, and a clear understanding of their diets and foraging strategies is essential for developing effective conservation strategies. In this paper, we compared diets and prey selection of snow leopards and wolves based on analyses of genotyped scats (snow leopards n = 182, wolves n = 57), collected within 26 sampling grid cells (5×5 km) that were distributed across a vast landscape of ca 5000 km2 in the Central Himalayas, Nepal. Within the grid cells, we sampled prey abundances using the double observer method. We found that interspecific differences in diet composition and prey selection reflected their respective habitat preferences, i.e. snow leopards significantly preferred cliff-dwelling wild ungulates (mainly bharal, 57% of identified material in scat samples), whereas wolves preferred typically plain-dwellers (Tibetan gazelle, kiang and argali, 31%). Livestock was consumed less frequently than their proportional availability by both predators (snow leopard = 27%; wolf = 24%), but significant avoidance was only detected among snow leopards. Among livestock species, snow leopards significantly preferred horses and goats, avoided yaks, and used sheep as available. We identified factors influencing diet composition using Generalized Linear Mixed Models. Wolves showed seasonal differences in the occurrence of small mammals/birds, probably due to the winter hibernation of an important prey, marmots. For snow leopard, occurrence of both wild ungulates and livestock in scats depended on sex and latitude. Wild ungulates occurrence increased while livestock decreased from south to north, probably due to a latitudinal gradient in prey availability. Livestock occurred more frequently in scats from male snow leopards (males: 47%, females: 21%), and wild ungulates more frequently in scats from females (males: 48%, females: 70%). The sexual difference agrees with previous

  18. An impulsive predator-prey model with disease in the prey for integrated pest management

    NASA Astrophysics Data System (ADS)

    Shi, Ruiqing; Chen, Lansun

    2010-02-01

    In this paper, an impulsive predator-prey model with disease in the prey is investigated for the purpose of integrated pest management. In the first part of the main results, we get the sufficient condition for the global stability of the susceptible pest-eradication periodic solution. This means if the release amount of infective prey and predator satisfy the condition, then the pest will be doomed. In the second part of the main results, we also get the sufficient condition for the permanence of the system. This means if the release amount of infective prey and predator satisfy the condition, then the prey and the predator will coexist. In the last section, we interpret our mathematical results. We also point out some possible future work.

  19. Forelimb indicators of prey-size preference in the Felidae.

    PubMed

    Meachen-Samuels, Julie; Van Valkenburgh, Blaire

    2009-06-01

    The forelimbs, along with the crania, are an essential part of the prey-killing apparatus in cats. Linear morphometrics of the forelimbs were used to determine the morphological differences between felids that specialize on large prey, small prey, or mixed prey. We also compared the scaling of felid forelimbs to those of canids to test whether prey capture strategies affect forelimb scaling. Results suggest that large prey specialists have relatively robust forelimbs when compared with smaller prey specialists. This includes relatively more robust humeri and radii, relatively larger distal ends of the humerus, and relatively larger articular areas of the humerus and radius. Large prey specialists also had relatively longer olecranon processes of the ulna and wider proximal paws. These characters are all important for subduing large prey while the cat positions itself for the killing bite. Small prey specialists have relatively longer distal limb elements for swift prey capture, and mixed prey specialists had intermediate values with relatively more robust metacarpals. Arboreal felids also had more robust limbs. They had relatively longer proximal phalanges for better grip while climbing, and a relatively short brachial index (radius to humerus ratio). Additionally, we found that felids and canids differ in forelimb scaling, which emphasizes the dual use of forelimbs for locomotion and prey capture in felids. This morphometric technique worked well to separate prey-size preference in felids, but did not work as well to separate locomotor groups, as scansorial and terrestrial felids were not clearly distinguished.

  20. Selective Predation of a Stalking Predator on Ungulate Prey.

    PubMed

    Heurich, Marco; Zeis, Klara; Küchenhoff, Helmut; Müller, Jörg; Belotti, Elisa; Bufka, Luděk; Woelfing, Benno

    2016-01-01

    Prey selection is a key factor shaping animal populations and evolutionary dynamics. An optimal forager should target prey that offers the highest benefits in terms of energy content at the lowest costs. Predators are therefore expected to select for prey of optimal size. Stalking predators do not pursue their prey long, which may lead to a more random choice of prey individuals. Due to difficulties in assessing the composition of available prey populations, data on prey selection of stalking carnivores are still scarce. We show how the stalking predator Eurasian lynx (Lynx lynx) selects prey individuals based on species identity, age, sex and individual behaviour. To address the difficulties in assessing prey population structure, we confirm inferred selection patterns by using two independent data sets: (1) data of 387 documented kills of radio-collared lynx were compared to the prey population structure retrieved from systematic camera trapping using Manly's standardized selection ratio alpha and (2) data on 120 radio-collared roe deer were analysed using a Cox proportional hazards model. Among the larger red deer prey, lynx selected against adult males-the largest and potentially most dangerous prey individuals. In roe deer lynx preyed selectively on males and did not select for a specific age class. Activity during high risk periods reduced the risk of falling victim to a lynx attack. Our results suggest that the stalking predator lynx actively selects for size, while prey behaviour induces selection by encounter and stalking success rates.

  1. Selective Predation of a Stalking Predator on Ungulate Prey

    PubMed Central

    Heurich, Marco; Zeis, Klara; Küchenhoff, Helmut; Müller, Jörg; Belotti, Elisa; Bufka, Luděk; Woelfing, Benno

    2016-01-01

    Prey selection is a key factor shaping animal populations and evolutionary dynamics. An optimal forager should target prey that offers the highest benefits in terms of energy content at the lowest costs. Predators are therefore expected to select for prey of optimal size. Stalking predators do not pursue their prey long, which may lead to a more random choice of prey individuals. Due to difficulties in assessing the composition of available prey populations, data on prey selection of stalking carnivores are still scarce. We show how the stalking predator Eurasian lynx (Lynx lynx) selects prey individuals based on species identity, age, sex and individual behaviour. To address the difficulties in assessing prey population structure, we confirm inferred selection patterns by using two independent data sets: (1) data of 387 documented kills of radio-collared lynx were compared to the prey population structure retrieved from systematic camera trapping using Manly’s standardized selection ratio alpha and (2) data on 120 radio-collared roe deer were analysed using a Cox proportional hazards model. Among the larger red deer prey, lynx selected against adult males—the largest and potentially most dangerous prey individuals. In roe deer lynx preyed selectively on males and did not select for a specific age class. Activity during high risk periods reduced the risk of falling victim to a lynx attack. Our results suggest that the stalking predator lynx actively selects for size, while prey behaviour induces selection by encounter and stalking success rates. PMID:27548478

  2. The birthday of a new syndrome: IgG4-related diseases constitute a clinical entity.

    PubMed

    Takahashi, Hiroki; Yamamoto, Motohisa; Suzuki, Chisako; Naishiro, Yasuyoshi; Shinomura, Yasuhisa; Imai, Kohzoh

    2010-07-01

    IgG4-related disease is a distinct clinical entity, whose characteristic features are the following; Serum IgG4 is prominently elevated, IgG4-positive plasma cells infiltrate in involved tissues, various mass-forming lesions with fibrosis develop in a timely and spatial manner and the response to corticosteroids is prompt and good. IgG4-related diseases mainly target two organs. One is the pancreas (autoimmune pancreatitis; AIP), and the other comprises the lacrimal and salivary glands, the clinical phenotype is Mikulicz's disease (MD). MD has long been considered a manifestation of Sjögren's syndrome (SS). However, we noticed several clinical differences in case of MD from SS; no deflection of female sex differences, mild sicca syndrome, good response to corticosteroids, no positivity of anti-SS-A/SS-B antibodies. In addition, elevated level of serum IgG4 and abundant infiltration of plasma cells expressing IgG4 were reported in MD patients. Those are common features of IgG4-related diseases. MD often coexisted with IgG4-related diseases such as AIP, retroperitoneal fibrosis, and IgG4-associated nephropathy. Based on those findings, it has been considered to recognize IgG4-related diseases including MD as a new clinical entity. The etiology of IgG4-related systemic diseases remains to be elucidated. It is necessary to accumulate and analyze larger data from patients worldwide.

  3. Defective immunoglobulin A (IgA) glycosylation and IgA deposits in patients with IgA nephropathy.

    PubMed

    Kolka, Ragnhildur; Valdimarsson, Helgi; Bodvarsson, Magnus; Hardarson, Sverrir; Jonsson, Thorbjorn

    2013-09-01

    Defective glycosylation and immune complex (IC) formation may be of primary importance in immunoglobulin A nephropathy (IgAN) pathogenesis. The aim of this study was to determine whether defective IgA1 glycosylation might support renal deposition of IgA and disease activity. IgA was isolated from the serum of 44 IgAN patients and 46 controls and glycosylation analysed by ELISA using glycan-specific lectins. IgA was measured by immunodiffusion and immune complexes by ELISA. IgA subclasses in IC deposits in kidney glomeruli were identified by immunohistochemical methods. A significant increase in N-acetylgalactosamine (GalNAc) in terminal position (p = 0.02) observed in some of the IgAN patients, became more pronounced when sialic acid was removed from IgA1, indicating enhanced expression of α-2,6-sialyltransferase in patients compared with controls (p < 0.0001). Patients with defective galactosylation had lower serum IgA than other IgAN patients (p = 0.003). IgAN patients with both IgA1 and IgA2 glomerular deposits (21.7%) had increased GalNAc in terminal position (p = 0.003). Taken together, our results show that increased IgA glycosylation in IgAN associates with low levels of IgA, concomitant IgA1 and IgA2 glomerular deposits and poor clinical outcome.

  4. Predator functional response and prey survival: Direct and indirect interactions affecting a marked prey population

    USGS Publications Warehouse

    Miller, David A.; Grand, J.B.; Fondell, T.F.; Anthony, M.

    2006-01-01

    1. Predation plays an integral role in many community interactions, with the number of predators and the rate at which they consume prey (i.e. their functional response) determining interaction strengths. Owing to the difficulty of directly observing predation events, attempts to determine the functional response of predators in natural systems are limited. Determining the forms that predator functional responses take in complex systems is important in advancing understanding of community interactions. 2. Prey survival has a direct relationship to the functional response of their predators. We employed this relationship to estimate the functional response for bald eagle Haliaeetus leucocepalus predation of Canada goose Branta canadensis nests. We compared models that incorporated eagle abundance, nest abundance and alternative prey presence to determine the form of the functional response that best predicted intra-annual variation in survival of goose nests. 3. Eagle abundance, nest abundance and the availability of alternative prey were all related to predation rates of goose nests by eagles. There was a sigmoidal relationship between predation rate and prey abundance and prey switching occurred when alternative prey was present. In addition, predation by individual eagles increased as eagle abundance increased. 4. A complex set of interactions among the three species examined in this study determined survival rates of goose nests. Results show that eagle predation had both prey- and predator-dependent components with no support for ratio dependence. In addition, indirect interactions resulting from the availability of alternative prey had an important role in mediating the rate at which eagles depredated nests. As a result, much of the within-season variation in nest survival was due to changing availability of alternative prey consumed by eagles. 5. Empirical relationships drawn from ecological theory can be directly integrated into the estimation process to

  5. Predator functional response and prey survival: direct and indirect interactions affecting a marked prey population.

    PubMed

    Miller, David A; Grand, James B; Fondell, Thomas F; Anthony, Michael

    2006-01-01

    1. Predation plays an integral role in many community interactions, with the number of predators and the rate at which they consume prey (i.e. their functional response) determining interaction strengths. Owing to the difficulty of directly observing predation events, attempts to determine the functional response of predators in natural systems are limited. Determining the forms that predator functional responses take in complex systems is important in advancing understanding of community interactions. 2. Prey survival has a direct relationship to the functional response of their predators. We employed this relationship to estimate the functional response for bald eagle Haliaeetus leucocepalus predation of Canada goose Branta canadensis nests. We compared models that incorporated eagle abundance, nest abundance and alternative prey presence to determine the form of the functional response that best predicted intra-annual variation in survival of goose nests. 3. Eagle abundance, nest abundance and the availability of alternative prey were all related to predation rates of goose nests by eagles. There was a sigmoidal relationship between predation rate and prey abundance and prey switching occurred when alternative prey was present. In addition, predation by individual eagles increased as eagle abundance increased. 4. A complex set of interactions among the three species examined in this study determined survival rates of goose nests. Results show that eagle predation had both prey- and predator-dependent components with no support for ratio dependence. In addition, indirect interactions resulting from the availability of alternative prey had an important role in mediating the rate at which eagles depredated nests. As a result, much of the within-season variation in nest survival was due to changing availability of alternative prey consumed by eagles. 5. Empirical relationships drawn from ecological theory can be directly integrated into the estimation process to

  6. Predator-prey interactions, resource depression and patch revisitation

    USGS Publications Warehouse

    Erwin, R.M.

    1989-01-01

    Generalist predators may be confronted by different types of prey in different patches: sedentary and conspicuous, cryptic (with or without refugia), conspicuous and nonsocial, or conspicuous and social. I argue that, where encounter rates with prey are of most importance, patch revisitation should be a profitable tactic where prey have short 'recovery' times (conspicuous, nonsocial prey), or where anti-predator response (e.g. shoaling) may increase conspicuousness. Predictions are made for how temporal changes in prey encounter rates should affect revisit schedules and feeding rates for the 4 different prey types.

  7. A non-autonomous stochastic predator-prey model.

    PubMed

    Buonocore, Aniello; Caputo, Luigia; Pirozzi, Enrica; Nobile, Amelia G

    2014-04-01

    The aim of this paper is to consider a non-autonomous predator-prey-like system, with a Gompertz growth law for the prey. By introducing random variations in both prey birth and predator death rates, a stochastic model for the predator-prey-like system in a random environment is proposed and investigated. The corresponding Fokker-Planck equation is solved to obtain the joint probability density for the prey and predator populations and the marginal probability densities. The asymptotic behavior of the predator-prey stochastic model is also analyzed.

  8. Role of IgA, IgG, and IgM antibodies against Haemophilus parainfluenzae antigens in IgA nephropathy.

    PubMed

    Suzuki, S; Gejyo, F; Nakatomi, Y; Odani, S; Sato, H; Arakawa, M

    1996-11-01

    We have recently demonstrated glomerular deposition of outer membranes of Haemophilus parainfluenzae (HP) antigens (OMHP) and the presence of IgA antibody against OMHP in patients with IgA nephropathy (IgA-N). In this study, we analyzed IgA-, IgG-, and IgM-classes of antibodies against OMHP, and the relationship between these antibodies and renal lesions in IgA-N. The subjects included 44 patients with IgA-N and 62 patients with outer glomerular diseases (OGD); the latter group consisted of 23 patients with predominantly IgG or IgM deposits and small amounts of IgA in the mesangium (group A), and 39 with IgG or IgM deposits without IgA (group B). IgA, IgG, and IgM antibodies against OMHP in patients sera were detected by enzyme-linked immunosorbent assay (ELISA). Immunoblotting demonstrated that the IgA, IgG, and IgM antibodies against OMHP in the sera of IgA-N patients bound to components of OMHP with molecular weights of 19.5, 30, and 40.5 kD. The amino acid compositions of these three OMHP components were similar to those reported for the outer membrane protein (OMP) P6 precursor, OMP P5, and OMP P2 (porin) of Haemophilus influenzae. Both IgA-N and group A patients, (i.e. those with IgA-related renal disease), demonstrated a significantly higher level of IgA antibodies against OMHP than did group B patients. However, only IgA-N patients revealed a significant correlation between the IgA-antibody titer and degree of glomerular changes. IgA-N patients with macroscopic hematuria or arterio(lo)sclerosis had a significantly higher IgA antibody titer than other IgA-N patients. There was no relationship between renal lesions and IgG or IgM antibody titers in any group. These findings suggest that IgA antibodies against OMHP are significantly increased in patients with IgA-related renal disease compared to those without mesangial IgA deposits and that a significant relationship between these antibodies and renal lesions exists only in patients with IgA-N.

  9. The clinical spectrum of IgG4-related disease.

    PubMed

    Brito-Zerón, Pilar; Ramos-Casals, Manuel; Bosch, Xavier; Stone, John H

    2014-12-01

    IgG4-related disease (IgG4-RD) is an emerging immune-mediated disease with the capability of involving essentially any organ. The epidemiology of this disease has not been explored in detail. A majority of patients reported in the literature to date are from Japan, but the condition has been described all across the world and there is no strong evidence to suggest a predilection for Asian populations. The mean age at diagnosis is approximately 60 years and there is a decided male predominance for many clinical features, with an overall male:female ratio of 8:3. A cardinal feature of IgG4-RD is single or multiple organ swelling that often raises concern for malignancy. IgG4-RD should be suspected in patients presenting with unexplained enlargement or swelling of one or more organs. Presenting features vary substantially according to the specialty to which patients present first; in addition, the disease can be diagnosed unexpectedly in pathological specimens or identified incidentally on radiology studies. Involvement of major organs is common and IgG4-RD may lead to organ failure, particularly in the pancreas, liver and biliary tree, kidneys, thyroid gland, lungs, and aorta. The diagnosis of IgG4-RD relies on the coexistence of various clinical, laboratory and histopathological findings, although none is pathognomonic by itself.

  10. Prey preference and life tables of the predatory mite Parasitus bituberosus (Acari: Parasitidae) when offered various prey combinations.

    PubMed

    Szafranek, Piotr; Lewandowski, Mariusz; Kozak, Marcin

    2013-09-01

    Parasitus bituberosus Karg (Acari: Parasitidae) is one of the predatory mite species inhabiting mushroom houses. It is known to accept a wide range of prey, suggesting that it may be a promising candidate for the biological control of key pests of mushroom culture. In our study it did not show any prey preference among four groups of small organisms often occurring in mushroom growth medium, namely rhabditid nematodes, pygmephorid mites, and sciarid and phorid fly larvae. Nevertheless, the type of food these predators fed on affects their development. The shortest egg-to-adult development time was obtained on a nematode diet. On a diet of phorid larvae, mite development stopped at the deutonymph stage; none reached adulthood. All other diets sufficed to reach the adult phase. Female fecundity when fed nematodes and sciarid larvae did not differ, but it was much lower when fed pygmephorid mites. Other life table parameters confirmed that pygmephorid mites constituted the worst diet for P. bituberosus. The highest intrinsic rate of population increase (r m = 0.34) was obtained on the nematode diet; when fed sciarid larvae and pygmephorid mites it was 0.25 and 0.14, respectively. Our study provides good reasons to further test P. bituberosus as biocontrol agent of especially sciarid flies and nematodes, especially when the compost is well colonized by mushroom mycelium (which retards nematode growth).

  11. Effects of prey quality and predator body size on prey DNA detection success in a centipede predator.

    PubMed

    Eitzinger, B; Unger, E M; Traugott, M; Scheu, S

    2014-08-01

    Predator body size and prey quality are important factors driving prey choice and consumption rates. Both factors might affect prey detection success in PCR-based gut content analysis, potentially resulting in over- or underestimation of feeding rates. Experimental evidence, however, is scarce. We examined how body size and prey quality affect prey DNA detection success in centipede predators. Due to metabolic rates increasing with body size, we hypothesized that prey DNA detection intervals will be shorter in large predators than in smaller ones. Moreover, we hypothesized that prey detection intervals of high-quality prey, defined by low carbon-to-nitrogen ratio will be shorter than in low-quality prey due to faster assimilation. Small, medium and large individuals of centipedes Lithobius spp. (Lithobiidae, Chilopoda) were fed Collembola and allowed to digest prey for up to 168 h post-feeding. To test our second hypothesis, medium-sized lithobiids were fed with either Diptera or Lumbricidae. No significant differences in 50% prey DNA detection success time intervals for a 272-bp prey DNA fragment were found between the predator size groups, indicating that body size does not affect prey DNA detection success. Post-feeding detection intervals were significantly shorter in Lumbricidae and Diptera compared to Collembola prey, apparently supporting the second hypothesis. However, sensitivity of diagnostic PCR differed between prey types, and quantitative PCR revealed that concentration of targeted DNA varied significantly between prey types. This suggests that both DNA concentration and assay sensitivity need to be considered when assessing prey quality effects on prey DNA detection success.

  12. Olfactive detection of fig wasps as prey by the ant Crematogaster scutellaris (Formicidae; Myrmicinae).

    PubMed

    Schatz, Bertrand; Anstett, Marie-Charlotte; Out, Welmoed; Hossaert-McKey, Martine

    2003-10-01

    In the species-specific and obligate mutualism between the fig (Ficus carica) and its pollinator (the fig wasps Blastophaga psenes), a third participant, the ant Crematogaster scutellaris, is a predator of the wasps. Here, we ask how ant workers can rapidly localise such prey, whose availability is limited in time and space. Using a Y-tube olfactometer, we tested ant response to odours emitted by different types of figs (receptive female, ripe female or male figs) and by fig wasps (pollinators or non-pollinators). We demonstrate that ants were significantly attracted only to odours emitted by pollinators, either alone or associated with odours of male figs (releasing wasps). Detection of prey odour by ants is an important trait that can explain their observed high rate of predation on pollinators, and could have important implications on the stability of the fig/fig wasp mutualism.

  13. Effect of light, prey density, and prey type on the feeding rates of Hemimysis anomala

    USGS Publications Warehouse

    Halpin, Kathleen E.; Boscarino, Brent T.; Rudstam, Lars G.; Walsh, Mureen G.; Lantry, Brian F.

    2013-01-01

    Hemimysis anomala is a near-shore mysid native to the Ponto-Caspian region that was discovered to have invaded Great Lakes ecosystems in 2006. We investigated feeding rates and prey preferences of adult and juvenile Hemimysis in laboratory experiments to gain insight on the potential for Hemimysis to disrupt food webs. For both age groups (AGs), we measured feeding rates as a function of prey abundance (Bosmina longirostris as prey), prey type (B. longirostris, Daphnia pulex, and Mesocyclops sp.), and light levels (no light and dim light). Mean feeding rates on Bosmina increased with prey density and reached 23 ind. (2 h)−1 for adults and 17 ind. (2 h)−1 for juveniles. Dim light had little effect on prey selection or feeding rate compared to complete darkness. When feeding rates on alternate prey were compared, both AGs fed at higher rates on Bosmina than Daphnia, but only juveniles fed at significantly higher rates on Bosmina relative to Mesocyclops. No significant differences were observed between feeding rates on Mesocyclops and on Daphnia. Hemimysis feeding rates were on the order of 30–60% of their body weight per day, similar to predatory cladocerans that have been implicated in zooplankton declines in Lakes Huron and Ontario.

  14. Functional response of wolves preying on barren-ground caribou in a multiple-prey ecosystem

    USGS Publications Warehouse

    Dale, B.W.; Adams, Layne G.; Bowyer, R.T.

    1994-01-01

    1. We investigated the functional response of wolves (Canis lupus) to varying abundance of ungulate prey to test the hypothesis that switching from alternate prey to preferred prey results in regulation of a caribou (Rangifer tarandus) population at low densities. 2. We determined prey selection, kill rates, and prey abundance for four wolf packs during three 30-day periods in March 1989, March 1990, November 1990, and created a simple discrete model to evaluate the potential for the expected numerical and observed functional responses of wolves to regulate caribou populations. 3. We observed a quickly decelerating type II functional response that, in the absence of numerical response, implicates an anti-regulatory effect of wolf predation on barren-ground caribou dynamics. 4. There was little potential for regulation caused by the multiplicative effect of increasing functional and numerical responses because of presence of alternative prey. This resulted in high wolf:caribou ratios at low prey densities which precluded the effects of an increasing functional response. 5. Inversely density-dependent predation by other predators, such as bears, reduces the potential for predators to regulate caribou populations at low densities, and small reductions in predation by one predator may have disproportionately large effects on the total predation rate.

  15. In men at risk of HIV infection, IgM, IgG1, IgG3, and IgA reach the human foreskin epidermis.

    PubMed

    Lemos, M P; Karuna, S T; Mize, G J; Fong, Y; Montano, S M; Ganoza, C; Lama, J R; Sanchez, J; McElrath, M J

    2016-05-01

    We profiled the humoral response in the penis, an area that has been minimally explored but may be relevant for protecting insertive men against HIV and other sexually acquired infections. Comparing paired tissue samples from 20 men at risk of HIV infection, foreskin contains less immunoglobulin A (IgA) and more IgG2 than colon. Using foreskin dermal and epidermal explants and paired plasma from 17 men, we examined Ig accumulation by normalizing Ig to human serum albumin (HSA) transudation. Dermal IgM, IgG2, IgA, and IgE ratios were greater than that in plasma, suggesting there is local antibody secretion at the dermis. Local Ig transcription was concentrated at the inner rather than the outer foreskin, and inner foreskin Ig ratios did not correlate with blood, indicating that localized production can contribute to the foreskin response. IgM, IgG1, IgG3, and IgA have preferential access to the foreskin epidermis, whereas IgG2, IgG4, and IgE are restricted to the dermis. Lastly, Ad5-specific IgA was selectively present in the colon, whereas foreskin Ad5 IgG was mainly derived from blood, and reached the inner epidermis at higher ratios than the outer (P<0.002). In summary, the foreskin antibody response combines local and systemic sources, and there is selective isotype accumulation in the epidermis.

  16. In Men at Risk of HIV Infection, IgM, IgG1, IgG3 and IgA Reach the Human Foreskin Epidermis

    PubMed Central

    Lemos, Maria P.; Karuna, Shelly T.; Mize, Gregory J.; Fong, Youyi; Montano, Silvia M.; Ganoza, Carmela; Lama, Javier R.; Sanchez, Jorge; McElrath, M. Juliana

    2015-01-01

    We profiled the humoral response in the penis, an area that has been minimally explored but may be relevant for protecting insertive men against HIV and other sexually-acquired infections. Comparing paired tissue samples from 20 men at risk of HIV infection, foreskin contains less IgA and more IgG2 than colon. Using foreskin dermal and epidermal explants and paired plasma from 17 men, we examined Ig accumulation by normalizing Ig to human serum albumin (HSA) transudation. Dermal IgM, IgG2, IgA, and IgE ratios were greater than in plasma, suggesting there is local antibody secretion at the dermis. Local Ig transcription was concentrated at the inner rather than the outer foreskin, and inner foreskin Ig ratios did not correlate with blood, indicating that localized production can contribute to the foreskin response. IgM, IgG1, IgG3, and IgA have preferential access to the foreskin epidermis, whereas IgG2, IgG4, and IgE are restricted to the dermis. Lastly, Ad5-specific IgA was selectively in the colon; whereas foreskin Ad5 IgG was mainly derived from blood, and reached the inner epidermis at higher ratios than the outer (p<0.002). In summary, the foreskin antibody response combines local and systemic sources and there is selective isotype accumulation in the epidermis. PMID:26509877

  17. Male courtship vibrations delay predatory behaviour in female spiders.

    PubMed

    Wignall, Anne E; Herberstein, Marie E

    2013-12-19

    During courtship, individuals transfer information about identity, mating status and quality. However, male web-building spiders face a significant problem: how to begin courting female spiders without being mistaken for prey? Male Argiope spiders generate distinctive courtship vibrations (shudders) when entering a female's web. We tested whether courtship shudders delay female predatory behaviour, even when live prey is present in the web. We presented a live cricket to females during playbacks of shudder vibrations, or white noise, and compared female responses to a control in which we presented a live cricket with no playback vibrations. Females were much slower to respond to crickets during playback of shudder vibrations. Shudder vibrations also delayed female predatory behaviour in a related spider species, showing that these vibrations do not simply function for species identity. These results suggest that male web-building spiders employ a phylogenetically conserved vibratory signal to ameliorate the risk of pre-copulatory cannibalism.

  18. Prey aggregation is an effective olfactory predator avoidance strategy.

    PubMed

    Johannesen, Asa; Dunn, Alison M; Morrell, Lesley J

    2014-01-01

    Predator-prey interactions have a major effect on species abundance and diversity, and aggregation is a well-known anti-predator behaviour. For immobile prey, the effectiveness of aggregation depends on two conditions: (a) the inability of the predator to consume all prey in a group and (b) detection of a single large group not being proportionally easier than that of several small groups. How prey aggregation influences predation rates when visual cues are restricted, such as in turbid water, has not been thoroughly investigated. We carried out foraging (predation) experiments using a fish predator and (dead) chironomid larvae as prey in both laboratory and field settings. In the laboratory, a reduction in visual cue availability (in turbid water) led to a delay in the location of aggregated prey compared to when visual cues were available. Aggregated prey suffered high mortality once discovered, leading to better survival of dispersed prey in the longer term. We attribute this to the inability of the dead prey to take evasive action. In the field (where prey were placed in feeding stations that allowed transmission of olfactory but not visual cues), aggregated (large groups) and semi-dispersed prey survived for longer than dispersed prey-including long term survival. Together, our results indicate that similar to systems where predators hunt using vision, aggregation is an effective anti-predator behaviour for prey avoiding olfactory predators.

  19. a Numerical Study on Predator Prey Model

    NASA Astrophysics Data System (ADS)

    Laham, Mohamed Faris; Krishnarajah, Isthrinayagy; Jumaat, Abdul Kadir

    Stochastic spatial models are becoming a popular tool for understand the ecological and evolution of ecosystem problems. We consider the predator prey interactions in term of stochastic representation of this Lotka-Volterra model and explore the use of stochastic processes to extinction behavior of the interacting populations. Here, we present simulation of stochastic processes of continuous time Lotka-Volterra model. Euler method has been used to solve the predator prey system. The trajectory spiral graph has been plotted based on obtained solution to show the population cycle of predator as a function of time.

  20. Predation risk increases dispersal distance in prey

    NASA Astrophysics Data System (ADS)

    Otsuki, Hatsune; Yano, Shuichi

    2014-06-01

    Understanding the ecological factors that affect dispersal distances allows us to predict the consequences of dispersal. Although predator avoidance is an important cause of prey dispersal, its effects on dispersal distance have not been investigated. We used simple experimental setups to test dispersal distances of the ambulatory dispersing spider mite ( Tetranychus kanzawai) in the presence or absence of a predator ( Neoseiulus womersleyi). In the absence of predators, most spider mites settled in adjacent patches, whereas the majority of those dispersing in the presence of predators passed through adjacent patches and settled in distant ones. This is the first study to experimentally demonstrate that predators induce greater dispersal distance in prey.

  1. Serum Concentrations of IgG4 in the Spanish Adult Population: Relationship with Age, Gender, and Atopy

    PubMed Central

    Carballo, Iago; Alvela, Lucía; Pérez, Luis-Fernando; Gude, Francisco; Vidal, Carmen; Alonso, Manuela; Sopeña, Bernardo; Gonzalez-Quintela, Arturo

    2016-01-01

    Background and Aim Serum IgG4 concentrations are commonly measured in clinical practice. The aim of this study was to investigate serum IgG4 concentrations in adults and their potential relationship with demographic, lifestyle, metabolic, and allergy-related factors. Methods Serum IgG4 concentrations were measured with a commercial assay in 413 individuals (median age 55 years, 45% males) who were randomly selected from a general adult population. Results Median IgG4 concentration was 26.8 mg/dL. Five out of the 413 individuals (1.2%) exhibited IgG4 concentrations >135 mg/dL, and 17 out of 411 (4.1%) exhibited an IgG4/total IgG ratio >8%. Serum IgG4 concentrations were significantly higher in males than in females and decreased with age. After adjusting for age and sex, serum IgG4 concentrations were not significantly influenced by alcohol consumption, smoking or common metabolic abnormalities (obesity and the related metabolic syndrome). Serum IgG4 concentrations were not significantly correlated with serum concentrations of proinflammatory cytokines and inflammation markers. Serum IgG4 concentrations were significantly correlated with IgE concentrations. Serum IgG4 concentrations tended to be higher in atopics (individuals with IgE-mediated sensitization to aeroallergens) than in non-atopics, particularly among atopics without respiratory symptoms. Serum IgG4 concentrations were not significantly correlated with total eosinophil blood count. Cases of IgG4-related disease were neither present at baseline nor detected after a median of 11 years of follow-up. Conclusions Studies aimed at defining reference IgG4 values should consider partitioning by age and sex. Further studies are needed to confirm the potential influence of atopy status on serum IgG4 concentrations. PMID:26910567

  2. IgG, IgM, and IgA antinuclear antibodies in discoid and systemic lupus erythematosus patients.

    PubMed

    Jost, Sheridan A; Tseng, Lin-Chiang; Matthews, Loderick A; Vasquez, Rebecca; Zhang, Song; Yancey, Kim B; Chong, Benjamin F

    2014-01-01

    IgG antinuclear antibodies (ANAs) are elevated in patients with systemic lupus erythematosus (SLE) compared with patients with discoid lupus erythematosus (DLE). To provide an expanded immunologic view of circulating ANAs in lupus patients, we compared the expressions of IgG, IgM, and IgA ANAs in DLE and SLE patients. In this cross-sectional study, sera from age-, gender-, and ethnic-matched SLE (N = 35), DLE (N = 23), and normal patients (N = 22) were tested for IgG, IgM, and IgA ANAs using enzyme-linked immunosorbent assays (ELISAs) and indirect immunofluorescence (IIF) with monkey esophagus as substrate. ELISAs showed elevated levels of IgG ANA, IgM ANA, and IgG/IgM ANA ratios in SLE patients compared with DLE and normal patients. IgA ANA expression was higher in SLE and DLE patients versus normal patients. IIF studies showed higher percentages of patients positive for IgG, IgM, and IgA ANAs in the SLE group. Higher IgG/IgM ANA ratios in SLE than DLE show enhanced class-switching and a more sustained humoral response in SLE. They also suggest a potential connection of IgM ANAs with disease containment.

  3. Arctic skate Amblyraja hyperborea preys on remarkably large glacial eelpouts Lycodes frigidus.

    PubMed

    Byrkjedal, I; Christiansen, J S; Karamushko, O V; Langhelle, G; Lynghammar, A

    2015-01-01

    During scientific surveys on the continental slopes north-west of Spitsbergen and off north-east Greenland (c. 600 and 1000 m depths), two female Arctic skates Amblyraja hyperborea were caught while swallowing extraordinary large individuals of glacial eelpout Lycodes frigidus. The total length (LT) of the prey constituted 50 and 80% of the LT of the skates, which reveal that A. hyperborea are capable predators of fishes of surprisingly large relative size.

  4. Female condoms

    MedlinePlus

    Condoms for women; Contraception - female condom; Family planning - female condom; Birth control - female condom ... care provider or pharmacy for information about emergency contraception (Plan B) if the condom tears or the ...

  5. Stability and Hopf bifurcation in a diffusive predator-prey system incorporating a prey refuge.

    PubMed

    Chang, Xiaoyuan; Wei, Junjie

    2013-08-01

    A diffusive predator-prey model with Holling type II functional response and the no-flux boundary condition incorporating a constant prey refuge is considered. Globally asymptotically stability of the positive equilibrium is obtained. Regarding the constant number of prey refuge m as a bifurcation parameter, by analyzing the distribution of the eigenvalues, the existence of Hopf bifurcation is given. Employing the center manifold theory and normal form method, an algorithm for determining the properties of the Hopf bifurcation is derived. Some numerical simulations for illustrating the analysis results are carried out.

  6. Human activity helps prey win the predator-prey space race.

    PubMed

    Muhly, Tyler B; Semeniuk, Christina; Massolo, Alessandro; Hickman, Laura; Musiani, Marco

    2011-03-02

    Predator-prey interactions, including between large mammalian wildlife species, can be represented as a "space race", where prey try to minimize and predators maximize spatial overlap. Human activity can also influence the distribution of wildlife species. In particular, high-human disturbance can displace large carnivore predators, a trait-mediated direct effect. Predator displacement by humans could then indirectly benefit prey species by reducing predation risk, a trait-mediated indirect effect of humans that spatially decouples predators from prey. The purpose of this research was to test the hypothesis that high-human activity was displacing predators and thus indirectly creating spatial refuge for prey species, helping prey win the "space race". We measured the occurrence of eleven large mammal species (including humans and cattle) at 43 camera traps deployed on roads and trails in southwest Alberta, Canada. We tested species co-occurrence at camera sites using hierarchical cluster and nonmetric multidimensional scaling (NMS) analyses; and tested whether human activity, food and/or habitat influenced predator and prey species counts at camera sites using regression tree analysis. Cluster and NMS analysis indicated that at camera sites humans co-occurred with prey species more than predator species and predator species had relatively low co-occurrence with prey species. Regression tree analysis indicated that prey species were three times more abundant on roads and trails with >32 humans/day. However, predators were less abundant on roads and trails that exceeded 18 humans/day. Our results support the hypothesis that high-human activity displaced predators but not prey species, creating spatial refuge from predation. High-human activity on roads and trails (i.e., >18 humans/day) has the potential to interfere with predator-prey interactions via trait-mediated direct and indirect effects. We urge scientist and managers to carefully consider and quantify the

  7. Size-dependent suitability of two mirids as prey for the cursorial spider Hibana futilis (Araneae: Anyphaenidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of 2nd and 4th instars and adult females of the cursorial spider, Hibana futilis (Banks), to prey on different stages of two mirid pests of cotton was examined. Small nymphs, large nymphs, and adults of the cotton fleahopper, Pseudomatoscelis seriatus (Reuter) and Creontiades signatus (...

  8. Prey escaping wolves, Canis lupus, despite close proximity

    USGS Publications Warehouse

    Nelson, M.E.; Mech, L.D.

    1993-01-01

    We describe attacks by wolf (Canis lupus) packs in Minnesota on a white-tailed deer (Odocoileus virginianus) and a moose (Alces alces) in which wolves were within contact distance of the prey but in which the prey escaped.

  9. A single predator charging a herd of prey: effects of self volume and predator-prey decision-making

    NASA Astrophysics Data System (ADS)

    Schwarzl, Maria; Godec, Aljaz; Oshanin, Gleb; Metzler, Ralf

    2016-06-01

    We study the degree of success of a single predator hunting a herd of prey on a two-dimensional square lattice landscape. We explicitly consider the self volume of the prey restraining their dynamics on the lattice. The movement of both predator and prey is chosen to include an intelligent, decision making step based on their respective sighting ranges, the radius in which they can detect the other species (prey cannot recognise each other besides the self volume interaction): after spotting each other the motion of prey and predator turns from a nearest neighbour random walk into directed escape or chase, respectively. We consider a large range of prey densities and sighting ranges and compute the mean first passage time for a predator to catch a prey as well as characterise the effective dynamics of the hunted prey. We find that the prey's sighting range dominates their life expectancy and the predator profits more from a bad eyesight of the prey than from his own good eye sight. We characterise the dynamics in terms of the mean distance between the predator and the nearest prey. It turns out that effectively the dynamics of this distance coordinate can be captured in terms of a simple Ornstein-Uhlenbeck picture. Reducing the many-body problem to a simple two-body problem by imagining predator and nearest prey to be connected by an effective Hookean bond, all features of the model such as prey density and sighting ranges merge into the effective binding constant.

  10. Behavioral Hypervolumes of Predator Groups and Predator-Predator Interactions Shape Prey Survival Rates and Selection on Prey Behavior.

    PubMed

    Pruitt, Jonathan N; Howell, Kimberly A; Gladney, Shaniqua J; Yang, Yusan; Lichtenstein, James L L; Spicer, Michelle Elise; Echeverri, Sebastian A; Pinter-Wollman, Noa

    2017-03-01

    Predator-prey interactions often vary on the basis of the traits of the individual predators and prey involved. Here we examine whether the multidimensional behavioral diversity of predator groups shapes prey mortality rates and selection on prey behavior. We ran individual sea stars (Pisaster ochraceus) through three behavioral assays to characterize individuals' behavioral phenotype along three axes. We then created groups that varied in the volume of behavioral space that they occupied. We further manipulated the ability of predators to interact with one another physically via the addition of barriers. Prey snails (Chlorostome funebralis) were also run through an assay to evaluate their predator avoidance behavior before their use in mesocosm experiments. We then subjected pools of prey to predator groups and recorded the number of prey consumed and their behavioral phenotypes. We found that predator-predator interactions changed survival selection on prey traits: when predators were prevented from interacting, more fearful snails had higher survival rates, whereas prey fearfulness had no effect on survival when predators were free to interact. We also found that groups of predators that occupied a larger volume in behavioral trait space consumed 35% more prey snails than homogeneous predator groups. Finally, we found that behavioral hypervolumes were better predictors of prey survival rates than single behavioral traits or other multivariate statistics (i.e., principal component analysis). Taken together, predator-predator interactions and multidimensional behavioral diversity determine prey survival rates and selection on prey traits in this system.

  11. Signal transduction by immunoglobulin is mediated through Ig alpha and Ig beta

    PubMed Central

    1993-01-01

    Immunoglobulin (Ig) antigen receptors are composed of a noncovalently- associated complex of Ig and two other proteins, Ig alpha and Ig beta. The cytoplasmic domain of both of these Ig associated proteins contains a consensus sequence that is shared with the signaling proteins of the T cell and Fc receptor. To test the idea that Ig alpha-Ig beta heterodimers are the signaling components of the Ig receptor, we have studied Ig mutations that interfere with signal transduction. We find that specific mutations in the transmembrane domain of Ig that inactivate Ca2+ and phosphorylation responses also uncouple IgM from Ig alpha-Ig beta. These results define amino acid residues that are essential for the assembly of the Ig receptor. Further, receptor activity can be fully reconstituted in Ca2+ flux and phosphorylation assays by fusing the cytoplasmic domain of Ig alpha with the mutant Igs. In contrast, fusion of the cytoplasmic domain of Ig beta to the inactive Ig reconstitutes only Ca2+ responses. Thus, Ig alpha and Ig beta are both necessary and sufficient to mediate signal transduction by the Ig receptor in B cells. In addition, our results suggest that Ig alpha and Ig beta can activate different signaling pathways. PMID:7688784

  12. Prey sex pheromone as kairomone for a new group of predators (Coleoptera: Dasytidae, Aplocnemus spp.) of pine bast scales.

    PubMed

    Branco, M; van Halder, I; Franco, J C; Constantin, R; Jactel, H

    2011-12-01

    During the last decades, an increasing number of predators were found to use specific prey pheromones as chemical cues. Beyond its ecological relevance, this knowledge has practical applications on insect conservation and pest control. In this study, we present first evidence that two species of the family Dasytidae (Coleoptera) Aplocnemus brevis Rosenhauer and A. raymondi Sainte-Claire Deville use the sex pheromone of the pine bast scale Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae) as kairomone to locate this prey. The feeding habits and biology of Aplocnemus species are practically unknown. In the laboratory, the adults of Aplocnemus sp. accepted M. feytaudi egg masses as food source as well as other diets. Females represented more than 90% of Aplocnemus sp. attracted to the pheromone lures. We believe that females use this olfactory cue to locate suitable places for oviposition and that larvae are the predators of Matsucoccus. This study further demonstrates that the response to the kairomone elicited short prey searching times, about 23% of the individuals appeared less than 12 min after lure exposure, being consistent with the hypothesis of prey specialization. Habitat and geographical distribution predict an ancestral association of A. brevis with M. feytaudi and of A. raymondi with M. pini. Nevertheless, a recent prey shift of A. raymondi to the invasive M. feytaudi in Corsica is in progress.

  13. Severe IgG4-Related Disease in a Young Child: A Diagnosis Challenge.

    PubMed

    Corujeira, Susana; Ferraz, Catarina; Nunes, Teresa; Fonseca, Elsa; Vaz, Luísa Guedes

    2015-01-01

    Immunoglobulin G4-related disease (IgG4-RD) is an increasingly recognized syndrome that can appear with multiple organ involvement, typically with tumor-like swelling, lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, and elevated serum IgG4 concentrations. We report the case of a 22-month-old female child with failure to thrive and recurrent respiratory tract infections since 8 months of age. Physical examination was normal except for pulmonary auscultation with bilateral crackles and wheezes. Laboratory tests revealed elevated erythrocyte sedimentation rate, and elevated serum IgG and IgG4 with polyclonal hypergammaglobulinemia. Thoracic CT and MRI showed multiple mediastinal lymphadenopathies and a nodular posterior mediastinal mass in right paratracheal location with bronchial compression. Initial fine needle aspiration biopsy was compatible with reactive lymphadenopathy but after clinical worsening a thoracoscopic partial resection of the mass was performed and tissue biopsy revealed lymphoplasmacytic infiltrate and increased number of IgG4-positive plasma cells and a ratio of IgG4/IgG positive cells above 40%. Glucocorticoids therapy was started with symptomatic improvement, reduction in the size of the mass, and decrease of serum IgG4 levels after 6 weeks. There are very few reports of IgG4-RD in children. Long-term follow-up is necessary to monitor relapses and additional organ involvement.

  14. Tetanus toxoid IgE may be useful in predicting allergy during childhood.

    PubMed

    Ciprandi, G; De Amici, M; Quaglini, S; Labò, E; Castellazzi, A M; Miraglia Del Giudice, M; Marseglia, A; Bianchi, L; Moratti, R; Marseglia, G L

    2012-01-01

    Hypersensitivity reactions after immunization with tetanus toxoid are occasionally observed in atopic and non-atopic individuals. High IgE levels in infancy may predict subsequent allergy. The aims of this study were: i) to evaluate the role of specific IgE to tetanus toxoid in children in response to tetanus immunization and the possible factors associated with specific IgE levels, and ii) to investigate the correlation between specific IgE levels to tetanus toxoid and the late development of allergy (up to 12 years). Initially, 278 healthy infants (152 males and 126 females, aged 12 months) living in an urban city were screened for serum total IgE and specific IgE to tetanus toxoid, after having obtained informed consent from parents. After 12 years, 151 children could be evaluated. Total IgE summed with tetanus specific IgE were significantly associated with allergy at 12 years. In conclusion, this study demonstrates that serum total IgE and tetanus specific IgE may be predictive of subsequent allergy onset.

  15. Large vessel involvement by IgG4-related disease

    PubMed Central

    Perugino, Cory A.; Wallace, Zachary S.; Meyersohn, Nandini; Oliveira, George; Stone, James R.; Stone, John H.

    2016-01-01

    Abstract Objectives: IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that can affect multiple organs and lead to tumefactive, tissue-destructive lesions. Reports have described inflammatory aortitis and periaortitis, the latter in the setting of retroperitoneal fibrosis (RPF), but have not distinguished adequately between these 2 manifestations. The frequency, radiologic features, and response of vascular complications to B cell depletion remain poorly defined. We describe the clinical features, radiology findings, and treatment response in a cohort of 36 patients with IgG4-RD affecting large blood vessels. Methods: Clinical records of all patients diagnosed with IgG4-RD in our center were reviewed. All radiologic studies were reviewed. We distinguished between primary large blood vessel inflammation and secondary vascular involvement. Primary involvement was defined as inflammation in the blood vessel wall as a principal focus of disease. Secondary vascular involvement was defined as disease caused by the effects of adjacent inflammation on the blood vessel wall. Results: Of the 160 IgG4-RD patients in this cohort, 36 (22.5%) had large-vessel involvement. The mean age at disease onset of the patients with large-vessel IgG4-RD was 54.6 years. Twenty-eight patients (78%) were male and 8 (22%) were female. Thirteen patients (36%) had primary IgG4-related vasculitis and aortitis with aneurysm formation comprised the most common manifestation. This affected 5.6% of the entire IgG4-RD cohort and was observed in the thoracic aorta in 8 patients, the abdominal aorta in 4, and both the thoracic and abdominal aorta in 3. Three of these aneurysms were complicated by aortic dissection or contained perforation. Periaortitis secondary to RPF accounted for 27 of 29 patients (93%) of secondary vascular involvement by IgG4-RD. Only 5 patients demonstrated evidence of both primary and secondary blood vessel involvement. Of those treated with

  16. Motor control: how dragonflies catch their prey.

    PubMed

    Dickinson, Michael H

    2015-03-16

    Detailed measurements of head and body motion have revealed previously unknown complexity in the predatory behavior of dragonflies. The new evidence suggests that the brains of these agile predators compute internal models of their own actions and those of their prey.

  17. Predators, prey, and natural disasters attract ecologists.

    PubMed

    Mlot, C

    1993-08-27

    Some 2200 ecologists turned out for the 78th annual meeting of the Ecological Society of America (ESA), held in Madison, Wisconsin, 31 July to 4 August. Among the offerings: reports on the effect of dams and levees on large river ecology, predator-prey interactions, how parasites might control evolution, and the impact of clearcutting on soil organisms.

  18. Diet, prey delivery rates, and prey biomass of Northern Goshawks in East-Central Arizona

    USGS Publications Warehouse

    Rogers, A.S.; DeStefano, S.; Ingraldi, M.F.

    2006-01-01

    Recent concern over persistence of Northern Goshawk (Accipiter gentilis) populations in Arizona has stemmed from two long-term demography studies that report substantial yearly fluctuations in productivity and evidence of a declining population. Although many factors could be involved in changes in productivity and population declines, availability of food is one such factor. As part of a demography study on the Sitgreaves portion of the Apache-Sitgreaves National Forest in Arizona, we used remote cameras to assess diets of goshawks. Northern Goshawks preyed upon 22 species during two nesting seasons. Adult pairs tended to specialize on particular species of prey. Prey delivery rates decreased throughout the nesting season with a corresponding increase in biomass in the latter stages of the nestling and fledgling periods. Adults appeared to take larger prey as nestlings increased in age.

  19. Molecular assessment of heterotrophy and prey digestion in zooxanthellate cnidarians.

    PubMed

    Leal, M C; Nejstgaard, J C; Calado, R; Thompson, M E; Frischer, M E

    2014-08-01

    Zooxanthellate cnidarians are trophically complex, relying on both autotrophy and heterotrophy. Although several aspects of heterotrophy have been studied in these organisms, information linking prey capture with digestion is still missing. We used prey-specific PCR-based tools to assess feeding and prey digestion of two zooxanthellate cnidarians - the tropical sea anemone Aiptasia sp. and the scleractinian coral Oculina arbuscula. Prey DNA disappeared rapidly for the initial 1-3 days, whereas complete digestion of prey DNA required up to 10 days in O. arbuscula and 5 or 6 days in Aiptasia sp. depending on prey species. These digestion times are considerably longer than previously reported from microscopy-based examination of zooxanthellate cnidarians and prey DNA breakdown in other marine invertebrates, but similar to prey DNA breakdown reported from terrestrial invertebrates such as heteroptera and spiders. Deprivation of external prey induced increased digestion rates during the first days after feeding in O. arbuscula, but after 6 days of digestion, there were no differences in the remaining prey levels in fed and unfed corals. This study indicates that prey digestion by symbiotic corals may be slower than previously reported and varies with the type of prey, the cnidarian species and its feeding history. These observations have important implications for bioenergetic and trophodynamic studies on zooxanthellate cnidarians.

  20. Alterations in prey capture and induction of metallothioneins in grass shrimp fed cadmium-contaminated prey

    SciTech Connect

    Wallace, W.G.; Hoexum Brouwer, T.M.; Brouwer, M.; Lopez, G.R.

    2000-04-01

    The aquatic oligochaete Limnodrilus hoffmeisteri from a Cd-contaminated cove on the Hudson River, Foundry Cove, New York, USA, has evolved Cd resistance. Past studies have focused on how the mode of detoxification of Cd by these Cd-resistant worms influences Cd trophic transfer to the grass shrimp Palaemonetes pugio. In the present study, the authors investigate reductions in prey capture in grass shrimp fed Cd-contaminated prey. They also investigate the induction of metal-binding proteins, metallothioneins, in these Cd-exposed shrimp. Grass shrimp were fed field-exposed Cd-contaminated Foundry Cove oligochaetes or laboratory-exposed Cd-contaminated Artemia salina. Following these exposures, the ability of Cd- dosed and control shrimp to capture live A. salina was compared. Results show that shrimp fed laboratory-exposed Cd-contaminated A. salina for 2 weeks exhibit significant reductions in their ability to successfully capture prey (live A. salina). Reductions in prey capture were also apparent, though not as dramatic in shrimp fed for 1 week on field-exposed Cd-contained Foundry Cove oligochaetes. Shrimp were further investigated for their subcellular distribution of Cd to examine if alterations in prey capture could be linked to saturation of Cd-metallothionein. Cd-dosed shrimp produced a low molecular weight CD-binding metallothionein protein in a dose- and time-dependent manner. Most importantly, successful prey capture decreased with increased Cd body burdens and increased Cd concentration bound to high molecular weight proteins.

  1. A predator-prey model with diseases in both prey and predator

    NASA Astrophysics Data System (ADS)

    Gao, Xubin; Pan, Qiuhui; He, Mingfeng; Kang, Yibin

    2013-12-01

    In this paper, we present and analyze a predator-prey model, in which both predator and prey can be infected. Each of the predator and prey is divided into two categories, susceptible and infected. The epidemics cannot be transmitted between prey and predator by predation. The predation ability of susceptible predators is stronger than infected ones. Likewise, it is more difficult to catch a susceptible prey than an infected one. And the diseases cannot be hereditary in both of the predator and prey populations. Based on the assumptions above, we find that there are six equilibrium points in this model. Using the base reproduction number, we discuss the stability of the equilibrium points qualitatively. Then both of the local and global stabilities of the equilibrium points are analyzed quantitatively by mathematical methods. We provide numerical results to discuss some interesting biological cases that our model exhibits. Lastly, we discuss how the infectious rates affect the stability, and how the other parameters work in the five possible cases within this model.

  2. Complex-to-Predict Generational Shift between Nested and Clustered Organization of Individual Prey Networks in Digger Wasps

    PubMed Central

    Ballesteros, Yolanda; Polidori, Carlo; Tormos, José; Baños-Picón, Laura; Asís, Josep Daniel

    2014-01-01

    Although diet has traditionally been considered to be a property of the species or populations as a whole, there is nowadays extensive knowledge that individual specialization is widespread among animal populations. Nevertheless, the factors determining the shape of interactions within food webs remain largely undiscovered, especially in predatory insects. We used an aggregation of the digger wasp Bembix merceti to 1) analyse patterns of individual prey use across three flying seasons in a network–based context; and 2) test the effect of four potential factors that might explain network topologies (wasp mass, nest spatial distribution, simultaneous nest-provisioning, prey availability). Inter-individual diet variation was found in all three years, under different predator-prey network topologies: Individuals arranged in dietary clusters and displayed a checkerboard pattern in 2009, but showed nestedness in 2008 and 2010. Network topologies were not fully explained by the tested factors. Larger females consumed a higher proportion of the total number of prey species captured by the population as a whole, in such a way that nested patterns may arise from mass-dependent prey spectrum width. Conversely, individuals with similar body mass didn’t form clusters. Nested patterns seemed to be associated with a greater availability of the main prey species (a proxy for reduced intra-specific competition). Thus, according with theory, clusters seemed to appear when competition increased. On the other hand, the nests of the individuals belonging to a given cluster were not more closely located, and neither did individuals within a cluster provision their nests simultaneously. Thus, a female-female copying behaviour during foraging was unlikely. In conclusion, wasp populations can maintain a considerable individual variation across years under different food web organizations. The tested factors only partially accounted for the shift in network properties, and new analyses

  3. Factors Affecting Growth of Tengmalm's Owl (Aegolius funereus) Nestlings: Prey Abundance, Sex and Hatching Order.

    PubMed

    Zárybnická, Markéta; Riegert, Jan; Brejšková, Lucie; Šindelář, Jiří; Kouba, Marek; Hanel, Jan; Popelková, Alena; Menclová, Petra; Tomášek, Václav; Šťastný, Karel

    2015-01-01

    In altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. A number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. Based on a seven-year observational study in a central European Tengmalm's owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mass and wing length, as well as the effect of prey abundance on parameters of growth curve. We found that nestling body mass varied among years, and parameters of growth curve, i.e. growth rate and inflection point in particular, increased with increasing abundance of the owl's main prey (Apodemus mice, Microtus voles), and pooled prey abundance (Apodemus mice, Microtus voles, and Sorex shrews). Furthermore, nestling body mass varied with hatching order and between sexes being larger for females and for the first-hatched brood mates. Brood size had no effect on nestling body mass. Simultaneously, we found no effect of year, brood size, hatching order, or sex on the wing length of nestlings. Our findings suggest that in this temperate owl population, nestling body mass is more sensitive to prey abundance than is wing length. The latter is probably more limited by the physiology of the species.

  4. Individual variation in space use by female spotted hyenas

    USGS Publications Warehouse

    Boydston, Erin E.; Kapheim, Karen M.; Szykman, Micaela; Holekamp, Kay E.

    2003-01-01

    Large carnivores range more widely than many other terrestrial mammals, and this behavior tends to bring them into frequent conflict with humans. Within any carnivore population, individual variation in patterns of space use should be expected to make some animals more vulnerable than others to risks of mortality from humans and other sources. In this study, our goal was to document variation among individuals in space use by female spotted hyenas (Crocuta crocuta). We examined predictions of hypotheses suggesting that space use by female hyenas is affected by reproductive state, social rank, and local prey abundance. Home-range size, distance at which females were found from the current communal den, and distance at which they were found from the nearest territorial boundary all varied significantly with the 3 independent variables. Females with den-dwelling cubs had smaller home ranges, were found closer to the communal den, and were found farther from the territorial boundary than were females with no den-dwelling cubs. Neither social rank nor prey availability significantly influenced the space-use patterns of females with den-dwelling cubs. Among females with no den-dwelling cubs, high-ranking females had smaller home ranges, were closer to the communal den, and were farther from the territorial boundary than were low-ranking females. The females ranging most widely were low-ranking individuals with no den-dwelling cubs when they were observed during periods of prey scarcity.

  5. Competition between Serum IgG, IgM, and IgA Anti-Glycan Antibodies

    PubMed Central

    Muthana, Saddam M.; Xia, Li; Campbell, Christopher T.; Zhang, Yalong; Gildersleeve, Jeffrey C.

    2015-01-01

    Anti-glycan antibodies are an abundant subpopulation of serum antibodies with critical functions in many immune processes. Changes in the levels of these antibodies can occur with the onset of disease, exposure to pathogens, or vaccination. As a result, there has been significant interest in exploiting anti-glycan antibodies as biomarkers for many diseases. Serum contains a mixture of anti-glycan antibodies that can recognize the same antigen, and competition for binding can potentially influence the detection of antibody subpopulations that are more relevant to disease processes. The most abundant antibody isotypes in serum are IgG, IgM, and IgA, but little is known regarding how these different isotypes compete for the same glycan antigen. In this study, we developed a multiplexed glycan microarray assay and applied it to evaluate how different isotypes of anti-glycan antibodies (IgA, IgG, and IgM) compete for printed glycan antigens. While IgG and IgA antibodies typically outcompete IgM for peptide or protein antigens, we found that IgM outcompete IgG and IgA for many glycan antigens. To illustrate the importance of this effect, we provide evidence that IgM competition can account for the unexpected observation that IgG of certain antigen specificities appear to be preferentially transported from mothers to fetuses. We demonstrate that IgM in maternal sera compete with IgG resulting in lower than expected IgG signals. Since cord blood contains very low levels of IgM, competition only affects maternal IgG signals, making it appear as though certain IgG antibodies are higher in cord blood than matched maternal blood. Taken together, the results highlight the importance of competition for studies involving anti-glycan antibodies. PMID:25807519

  6. Blood Test: Immunoglobulin A (IgA)

    MedlinePlus

    ... to 2-Year-Old Blood Test: Immunoglobulin A (IgA) KidsHealth > For Parents > Blood Test: Immunoglobulin A (IgA) Print A A A What's in this article? ... Questions en español Análisis de sangre: inmunoglobulina A (IgA) What It Is An IgA test measures the ...

  7. Predator personality and prey behavioural predictability jointly determine foraging performance.

    PubMed

    Chang, Chia-Chen; Teo, Huey Yee; Norma-Rashid, Y; Li, Daiqin

    2017-01-17

    Predator-prey interactions play important roles in ecological communities. Personality, consistent inter-individual differences in behaviour, of predators, prey or both are known to influence inter-specific interactions. An individual may also behave differently under the same situation and the level of such variability may differ between individuals. Such intra-individual variability (IIV) or predictability may be a trait on which selection can also act. A few studies have revealed the joint effect of personality types of both predators and prey on predator foraging performance. However, how personality type and IIV of both predators and prey jointly influence predator foraging performance remains untested empirically. Here, we addressed this using a specialized spider-eating jumping spider, Portia labiata (Salticidae), as the predator, and a jumping spider, Cosmophasis umbratica, as the prey. We examined personality types and IIVs of both P. labiata and C. umbratica and used their inter- and intra-individual behavioural variation as predictors of foraging performance (i.e., number of attempts to capture prey). Personality type and predictability had a joint effect on predator foraging performance. Aggressive predators performed better in capturing unpredictable (high IIV) prey than predictable (low IIV) prey, while docile predators demonstrated better performance when encountering predictable prey. This study highlights the importance of the joint effect of both predator and prey personality types and IIVs on predator-prey interactions.

  8. Effects of uniform rotational flow on predator-prey system

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee

    2012-12-01

    Rotational flow is often observed in lotic ecosystems, such as streams and rivers. For example, when an obstacle interrupts water flowing in a stream, energy dissipation and momentum transfer can result in the formation of rotational flow, or a vortex. In this study, I examined how rotational flow affects a predator-prey system by constructing a spatially explicit lattice model consisting of predators, prey, and plants. A predation relationship existed between the species. The species densities in the model were given as S (for predator), P (for prey), and G (for plant). A predator (prey) had a probability of giving birth to an offspring when it ate prey (plant). When a predator or prey was first introduced, or born, its health state was assigned an initial value of 20 that subsequently decreased by one with every time step. The predator (prey) was removed from the system when the health state decreased to less than zero. The degree of flow rotation was characterized by the variable, R. A higher R indicates a higher tendency that predators and prey move along circular paths. Plants were not affected by the flow because they were assumed to be attached to the streambed. Results showed that R positively affected both predator and prey survival, while its effect on plants was negligible. Flow rotation facilitated disturbances in individuals’ movements, which consequently strengthens the predator and prey relationship and prevents death from starvation. An increase in S accelerated the extinction of predators and prey.

  9. Oscillations in a size-structured prey-predator model.

    PubMed

    Bhattacharya, Souvik; Martcheva, Maia

    2010-11-01

    This article introduces a predator-prey model with the prey structured by body size, based on reports in the literature that predation rates are prey-size specific. The model is built on the foundation of the one-species physiologically structured models studied earlier. Three types of equilibria are found: extinction, multiple prey-only equilibria and possibly multiple predator-prey coexistence equilibria. The stabilities of the equilibria are investigated. Comparison is made with the underlying ODE Lotka-Volterra model. It turns out that the ODE model can exhibit sustain oscillations if there is an Allee effect in the net reproduction rate, that is the net reproduction rate grows for some range of the prey's population size. In contrast, it is shown that the structured PDE model can exhibit sustain oscillations even if the net reproductive rate is strictly declining with prey population size. We find that predation, even size-non-specific linear predation can destabilize a stable prey-only equilibrium, if reproduction is size specific and limited to individuals of large enough size. Furthermore, we show that size-specific predation can also destabilize the predator-prey equilibrium in the PDE model. We surmise that size-specific predation allows for temporary prey escape which is responsible for destabilization in the predator-prey dynamics.

  10. Predator personality and prey behavioural predictability jointly determine foraging performance

    PubMed Central

    Chang, Chia-chen; Teo, Huey Yee; Norma-Rashid, Y.; Li, Daiqin

    2017-01-01

    Predator-prey interactions play important roles in ecological communities. Personality, consistent inter-individual differences in behaviour, of predators, prey or both are known to influence inter-specific interactions. An individual may also behave differently under the same situation and the level of such variability may differ between individuals. Such intra-individual variability (IIV) or predictability may be a trait on which selection can also act. A few studies have revealed the joint effect of personality types of both predators and prey on predator foraging performance. However, how personality type and IIV of both predators and prey jointly influence predator foraging performance remains untested empirically. Here, we addressed this using a specialized spider-eating jumping spider, Portia labiata (Salticidae), as the predator, and a jumping spider, Cosmophasis umbratica, as the prey. We examined personality types and IIVs of both P. labiata and C. umbratica and used their inter- and intra-individual behavioural variation as predictors of foraging performance (i.e., number of attempts to capture prey). Personality type and predictability had a joint effect on predator foraging performance. Aggressive predators performed better in capturing unpredictable (high IIV) prey than predictable (low IIV) prey, while docile predators demonstrated better performance when encountering predictable prey. This study highlights the importance of the joint effect of both predator and prey personality types and IIVs on predator-prey interactions. PMID:28094288

  11. Are all prey created equal? A review and synthesis of differential predation on prey in substandard condition

    USGS Publications Warehouse

    Mesa, Matthew G.; Poe, Thomas P.; Gadomski, Dena M.; Petersen, James H.

    1994-01-01

    Our understanding of predator-prey interactions in fishes has been influenced largely by research assuming that the condition of the participants is normal. However, fish populations today often reside in anthropogenically altered environments and are subjected to many kinds of stressors, which may reduce their ecological performance by adversely affecting their morphology, physiology, or behaviour. One consequence is that either the predator or prey, or both, may be in a substandard condition at the time of an interaction. We reviewed the literature on predator-prey interactions in fishes where substandard prey were used as experimental groups. Although most of this research indicates that such prey are significantly more vulnerable to predation, prey condition has rarely been considered in ecological theory regarding predator-prey interactions. The causal mechanisms for increased vulnerability of substandard prey to predation include a failure to detect predators, lapses in decision-making, poor fast-start performance, inability to shoal effectively, and increased prey conspicuousness. Despite some problems associated with empirical predator-prey studies using substandard prey, their results can have theoretical and applied uses, such as in ecological modelling or justification of corrective measures to be implemented in the wild. There is a need for more corroborative field experimentation, a better understanding of the causal mechanisms behind differential predation, and increased incorporation of prey condition into the research of predator-prey modellers and theoreticians. If the concept of prey condition is considered in predator-prey interactions, our understanding of how such interactions influence the structure and dynamics of fish communities is likely to change, which should prove beneficial to aquatic ecosystems.

  12. Observations on the Nesting and Prey of the Solitary Wasp, Tachysphex inconspicuus, with a Review of Nesting Behavior in the T. obscuripennis species group

    PubMed Central

    Kurczewski, Frank E.; Coville, Rollin E.; Schal, Coby

    2010-01-01

    The nesting behaviors of 10 females of Tachysphex inconspicuus (Kirby) (Hymenoptera: Crabronidae) were studied on a sandy, mowed lawn at the La Selva Biological Station in northeastern Costa Rica on 27–29 April 1980. Twenty-four completed nests were observed, excavated, and measured. The nests had oblique, short burrows leading to one or two shallow cells. Prey cockroaches belonging to 11 species of Chorisoneura and Riatia fulgida (Saussure) (Blattaria: Blattellidae), all tropical wet forest canopy indicator species, were removed from the cells, weighed, and identified. The cockroaches consisted mainly of adult females, selectively preyed upon over adult males and nymphs due to their larger sizes. The aggregate prey mass in cells was separable into prospective larger (heavier) female and smaller (lighter) male cells. Wasps usually oviposited on the heaviest cockroach in a cell, in most cases an adult female. Atypical genus behavior included (1) prey being carried to one side of the wasp and perhaps grasped by a hindleg during removal of the temporary entrance closure and nest entry and (2) wasp's egg being laid affixed to a forecoxal corium and extending backward in a longitudinally posteriad position across the prey's ventral thorax. A comparison with the nesting behavior of other species in the Tachysphex obscuripennis species group is made. PMID:21062142

  13. Serum IgD and IgE in rheumatoid arthritis.

    PubMed

    Marcolongo, R; Marsili, C

    1975-02-01

    Serum immunoglobulins IgD and IgE have been determined by a single radial immunodiffusion technique and a radioimmunoassay method in serum samples from 95 rheumatoid patients, 5 subjects with Sjögren's syndrome and 50 healthy controls, and compared with levels of IgG, IgM and IgA fractions measured in the same subjects. The IgD and IgE serum content resulted similar in the rheumatoid, Sjögren's and control sera. No correlation of IgD and IgE values with changes of other immunoglobulins or with the activity and the duration of the rheumatoid disease was observed.

  14. A focus on long-run sustainability of a harvested prey predator system in the presence of alternative prey.

    PubMed

    Kar, T K; Chattopadhyay, S K

    2010-01-01

    Within the framework of a general equilibrium model we study the long-run dynamics of a prey-predator model in the presence of an alternative prey. Our results show that sustainability, i.e. a positive value of the population in the long run, essentially depends on individual harvesting efforts and digesting factors relative to alternative prey. A detailed bifurcation analysis evidences the richness of possible long-run dynamics. Our model clearly shows that the role of an alternative prey must be taken into consideration when studying prey-predator dynamics.

  15. Influence of experimental alcohol administration on serum immunoglobulin levels: contrasting effects on IgE and other immunoglobulin classes.

    PubMed

    Alonso, M; Gomez-Rial, J; Gude, F; Vidal, C; Gonzalez-Quintela, A

    2012-01-01

    In humans, alcoholic liver disease is associated with hypergammaglobulinemia, particularly with high serum concentrations of IgA. Furthermore, alcohol consumption is associated with high concentrations of IgE and low concentrations of IgG. However, there is little experimental evidence to corroborate these observational findings. The objective of the present study was to investigate the potential short-term effects of alcohol administration on serum immunoglobulin concentrations in mice, and the potential influence of sex and strain on these effects. Eight mouse groups were defined by strain (Swiss vs C57BL/6), sex (male vs female), and experimental procedure (alcohol administration vs control diet). Alcohol was administered in a semi-liquid diet (6.5%v/v); control animals received an isocaloric semi-liquid diet. Immunoglobulin concentrations (IgE, IgA, IgM, IgG1, IgG2a, IgG2b, and IgG3) were measured at baseline and weekly thereafter for 4 weeks. Serum Th1 (interferon-gamma) and Th2 (IL-4 and IL-13) cytokines were measured at week 4. We found significant variations in baseline immunoglobulin concentrations depending upon mouse sex and strain. Alcohol administration was quickly followed by an increase in serum IgE concentrations in all experimental groups. IgE increase was correlated with serum IL-13 increase. In contrast, alcohol administration was not associated with significant changes in serum IgA and IgM concentration, and appeared to decrease IgG subclass concentrations. Alcohol effects on immunoglobulin concentrations were independent of mouse strain and sex. In conclusion, alcohol administration in mice had contrasting effects on IgE and other immunoglobulin classes. This experimental evidence confirms observational results in humans.

  16. Preparing the perfect cuttlefish meal: complex prey handling by dolphins.

    PubMed

    Finn, Julian; Tregenza, Tom; Norman, Mark

    2009-01-01

    Dolphins are well known for their complex social and foraging behaviours. Direct underwater observations of wild dolphin feeding behaviour however are rare. At mass spawning aggregations of giant cuttlefish (Sepia apama) in the Upper Spencer Gulf in South Australia, a wild female Indo-Pacific bottlenose dolphin (Tursiops aduncus) was observed and recorded repeatedly catching, killing and preparing cuttlefish for consumption using a specific and ordered sequence of behaviours. Cuttlefish were herded to a sand substrate, pinned to the seafloor, killed by downward thrust, raised mid-water and beaten by the dolphin with its snout until the ink was released and drained. The deceased cuttlefish was then returned to the seafloor, inverted and forced along the sand substrate in order to strip the thin dorsal layer of skin off the mantle, thus releasing the buoyant calcareous cuttlebone. This stepped behavioural sequence significantly improves prey quality through 1) removal of the ink (with constituent melanin and tyrosine), and 2) the calcareous cuttlebone. Observations of foraging dolphin pods from above-water at this site (including the surfacing of intact clean cuttlebones) suggest that some or all of this prey handling sequence may be used widely by dolphins in the region. Aspects of the unique mass spawning aggregations of giant cuttlefish in this region of South Australia may have contributed to the evolution of this behaviour through both high abundances of spawning and weakened post-spawning cuttlefish in a small area (>10,000 animals on several kilometres of narrow rocky reef), as well as potential long-term and regular visitation by dolphin pods to this site.

  17. Phytophagy of the predator Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae) fed on prey and Brassicaceae.

    PubMed

    Grigolli, J F J; Grigolli, M M Kubota; Ramalho, D G; Martins, A L; Vacari, A M; De Bortoli, S A

    2017-03-13

    The purpose of this study was to investigate the development and reproduction of the zoophytophagous predator Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) fed kale, broccoli and cabbage affects its. Nymphs and adults of this predator were fed on larvae of Plutella xylostella (L.) (Lepidoptera: Plutellidae) as prey with kale, cabbage, or broccoli. In the nymph period, the duration and prey consumption were similar with all the Brassicacea cultivar. However, nymph viability was higher for predators with broccoli leaves. The mean weight of 5th-instar nymphs, newly emerged females and the sex ratio were similar among the Brassicacea cultivars, while newly emerged males were heavier with kale and broccoli leaves. The supply of broccoli leaves resulted in greater oviposition, higher number of eggs per egg mass and longer longevity of P. nigrispinus males and females. Furthermore, the consumption of P. xylostella larvae by adult predators was higher with these cultivars. The net reproductive rate (R0) and mean generation time (T) were highest for predators with prey and broccoli leaves. The reproductive parameters of P. nigrispinus were enhanced when fed on P. xylostella larvae with and broccoli leaves, which can be an alternative diet in laboratory rearing of this predator.

  18. A Predator from East Africa that Chooses Malaria Vectors as Preferred Prey

    PubMed Central

    Nelson, Ximena J.; Jackson, Robert R.

    2006-01-01

    Background All vectors of human malaria, a disease responsible for more than one million deaths per year, are female mosquitoes from the genus Anopheles. Evarcha culicivora is an East African jumping spider (Salticidae) that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey. Methodology/Principal Findings By testing with motionless lures made from mounting dead insects in lifelike posture on cork discs, we show that E. culicivora selects Anopheles mosquitoes in preference to other mosquitoes and that this predator can identify Anopheles by static appearance alone. Tests using active (grooming) virtual mosquitoes rendered in 3-D animation show that Anopheles' characteristic resting posture is an important prey-choice cue for E. culicivora. Expression of the spider's preference for Anopheles varies with the spider's size, varies with its prior feeding condition and is independent of the spider gaining a blood meal. Conclusions/Significance This is the first experimental study to show that a predator of any type actively chooses Anopheles as preferred prey, suggesting that specialized predators having a role in the biological control of disease vectors is a realistic possibility. PMID:17205136

  19. IgG4-related inflammation of the orbit simulating malignant lymphoma.

    PubMed

    Kase, Satoru; Noda, Mika; Ishijima, Kan; Yamamoto, Teppei; Hatanaka, Kanako; Ishida, Susumu

    2013-06-01

    Immunoglobulin (IgG) 4-related disease is characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. We report a case of IgG4-related inflammation of the orbit simulating extranodal marginal zone B-cell lymphoma (EMZL). A 72-year-old female complained of bilateral eyelid swelling for three years. A MRI scan demonstrated two kinds of lesions, tumor 1, presenting with a predominantly low density, and tumor 2, of relatively high density. Laboratory tests showed high serum IgG4 concentrations, measuring 991 mg/dl. Partial resection of each tumor was conducted in September 2011. Based on the clinicopathological findings, tumors 1 and 2 were diagnosed as IgG4-related inflammation and EMZL, respectively. The patient initially received oral prednisolone at 30 mg/per day, followed by irradiation with a total dosage of 30 Gy to both eyes. The bilateral tumors consequently diminished, and she is currently well with no recurrence or systemic involvement. In conclusion, EMZL can arise from massive IgG4-related orbital inflammation. Since IgG4-related inflammation can represent multiple nodular lesions, biopsies from multiple sites within the lesion are required to make a correct diagnosis in selected cases. Oral prednisolone combined with radiotherapy is an effective treatment for patients with IgG4-related ophthalmic disease simulating EMZL.

  20. IgG4-Related Tubulointerstitial Nephritis.

    PubMed

    Zhang, Pingchuan; Cornell, Lynn D

    2017-03-01

    Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a fibroinflammatory disorder that can involve nearly any organ. The disorder has increasingly become known as a distinct clinical entity during the last decade. IgG4-related tubulointerstitial nephritis (IgG4-TIN) is the most common manifestation of IgG4-RD in the kidney. Many patients with IgG4-TIN are diagnosed after IgG4-RD has been recognized in other organ systems, but the kidney may also be the first or only site involved. The presenting clinical features of IgG4-TIN are most commonly kidney insufficiency, kidney mass lesion(s), or both. On biopsy, IgG4-TIN shows a dense lymphoplasmacytic infiltrate, increased IgG4+ plasma cells, storiform fibrosis, and often tubular basement membrane immune complex deposits. Elevation of serum IgG4 often accompanies IgG4-RD; however, it is not specific in reaching the diagnosis. Like IgG4-RD in other organs, IgG4-TIN characteristically responds promptly to steroids, although there is a high relapse rate on discontinuation of immunosuppression. The pathogenesis of IgG4-RD is not understood.

  1. Motional instabilities in prey-predator systems.

    PubMed

    Malchow, H

    2000-06-21

    Differential fluxes can destabilize the locally stable stationary density distributions in interaction systems with diffusion, advection, and/or locomotion of chemical or biological species. By this method they can cause the formation of stationary or travelling spatial structures. Different scenarios of this general mechanism of spatio-temporal pattern formation in reaction-diffusion-advection systems will be demonstrated, using a simple two-species predator-prey system as an example model.

  2. Pollinator-prey conflict in carnivorous plants.

    PubMed

    Jürgens, Andreas; Sciligo, Amber; Witt, Taina; El-Sayed, Ashraf M; Suckling, D Max

    2012-08-01

    Most carnivorous plants utilize insects in two ways: the flowers attract insects as pollen vectors for sexual reproduction, and the leaves trap insects for nutrients. Feeding on insects has been explained as an adaptation to nutrient-poor soil, and carnivorous plants have been shown to benefit from insect capture through increased growth, earlier flowering and increased seed production. Most carnivorous plant species seem to benefit from insect pollination, although many species autonomously self-pollinate and some propagate vegetatively. However, assuming that outcross pollen is advantageous and is a more important determinant of reproductive success than the nutrients gained from prey, there should be a selective pressure on carnivorous plants not to feed on their potential pollen vectors. Therefore, it has been suggested that carnivorous plants are subject to a conflict, often called the pollinator-prey conflict (PPC). The conflict results from a trade-off of the benefits from feeding on potentially pollinating insects versus the need to use them as pollen vectors for sexual reproduction. In this review we analyze the conditions under which a PPC may occur, review the evidence for the existence of PPCs in carnivorous plants, and explore the mechanisms that may be in place to prevent or alleviate a PPC. With respect to the latter, we discuss how plant signals such as olfactory and visual cues may play a role in separating the functions of pollinator attraction and prey capture.

  3. Mammals as prey: estimating ingestible size.

    PubMed

    Close, Matthew; Cundall, David

    2012-09-01

    Most mammals have deformable bodies, making it difficult to measure the size of living or freshly killed ones accurately. Because small rodents are common prey of many snakes, and because nearly all snakes swallow their prey whole, we explored four methods for determining the ingestible size (the smallest cross-sectional area that the largest part of the rodent can be made into without breaking bones or dislocating joints) of 100 intact rodents, including 50 Musmusculus and 50 Rattus norvegicus. Cross-sectional areas derived from maximal height and width of specimens at rest or the same specimens wrapped snout to pelvic girdle are roughly 1.5× higher than areas calculated either by the height and width of the same specimens rolled into cylinders or by volumetric displacement. Rolling rodents into cylinders reduces cross-sectional area by straightening the vertebral column, lengthening the abdominal cavity, elevating the sternum, compressing the thoracic cavity, and protracting the shoulder joint, that is, changes similar to those seen in rodents eaten by snakes. Reduced major axis regression of the smallest attainable cross-sectional area, y, on mass, x, shows that y (in log mm(2) ) approximates 1.53x (in log grams)(0.69) for rats and 1.63x(0.64) for mice. Our results suggest that visual cues provided by live rodents might lead most predators, like snakes, to overestimate ingestible size and hence rarely attack prey too large to ingest.

  4. Predator-prey interactions mediated by prey personality and predator hunting mode.

    PubMed

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-04-13

    Predator-prey interactions are important drivers in structuring ecological communities. However, despite widespread acknowledgement that individual behaviours and predator species regulate ecological processes, studies have yet to incorporate individual behavioural variations in a multipredator system. We quantified a prevalent predator avoidance behaviour to examine the simultaneous roles of prey personality and predator hunting mode in governing predator-prey interactions. Mud crabs, Panopeus herbstii, reduce their activity levels and increase their refuge use in the presence of predator cues. We measured mud crab mortality and consistent individual variations in the strength of this predator avoidance behaviour in the presence of predatory blue crabs, Callinectes sapidus, and toadfish, Opsanus tau We found that prey personality and predator species significantly interacted to affect mortality with blue crabs primarily consuming bold mud crabs and toadfish preferentially selecting shy crabs. Additionally, the strength of the predator avoidance behaviour depended upon the predation risk from the predator species. Consequently, the personality composition of populations and predator hunting mode may be valuable predictors of both direct and indirect predator-prey interaction strength. These findings support theories postulating mechanisms for maintaining intraspecies diversity and have broad implications for community dynamics.

  5. Differentiation of membrane IgE+ rat B cells into IgE-secreting cells.

    PubMed Central

    Vanhove, B; Bazin, H

    1993-01-01

    Rat spleen cells were stimulated with pokeweed mitogen (PWM) and the IgM and IgE responses were assessed. An enrichment of the cell suspension with IgE-bearing cells before stimulation resulted in an increase in the number of IgE-secreting cells. A decrease of the number of IgE-secreting cells was found after depletion of IgE- or IgM-bearing cells, but not those bearing IgD molecules on their membranes, before stimulation. Moreover, the stimulation of membrane IgE on B cells with anti-IgE antibodies was shown to increase the number of IgE-secreting cells after PWM-induced differentiation in vitro. In vivo, it was also observed that a single injection of anti-IgE antibodies can induce the differentiation of IgE-secreting cells. These results demonstrate the presence of IgE(+)-IgM (+)-IgD- B cells in the rat that are responsive to PWM-induced differentiation into IgE-secreting cells. They indicate a pre-commitment of these cells at a stage where they still express IgM on their surface. IgE molecules on the cell membranes play a role in their differentiation. PMID:8406582

  6. Problems with studying wolf predation on small prey in summer via global positioning system collars

    USGS Publications Warehouse

    Palacios, V.; Mech, L.D.

    2011-01-01

    We attempted to study predation on various-sized prey by a male and female wolf (Canis lupus) with global positioning system (GPS) collars programmed to acquire locations every 10 min in the Superior National Forest of Minnesota. During May to August 2007, we investigated 147 clusters of locations (31% of the total) and found evidence of predation on a white-tailed deer (Odocoileus virginianus) fawn and yearling, a beaver (Castor canadensis), ruffed grouse (Bonasa umbellus), and fisher (Martes pennanti) and scavenging on a road-killed deer and other carrion. However, we missed finding many prey items and discuss the problems associated with trying to conduct such a study. ?? 2010 US Government.

  7. Prey selection by the Lake Superior fish community

    USGS Publications Warehouse

    Isaac, Edmund J.; Hrabik, Thomas R.; Stockwell, Jason D.; Gamble, Allison E.

    2012-01-01

    Mysis diluviana is an important prey item to the Lake Superior fish community as found through a recent diet study. We further evaluated this by relating the quantity of prey found in fish diets to the quantity of prey available to fish, providing insight into feeding behavior and prey preferences. We describe the seasonal prey selection of major fish species collected across 18 stations in Lake Superior in spring, summer, and fall of 2005. Of the major nearshore fish species, bloater (Coregonus hoyi), rainbow smelt (Osmerus mordax), and lake whitefish (Coregonus clupeaformis) consumed Mysis, and strongly selected Mysis over other prey items each season. However, lake whitefish also selected Bythotrephes in the fall when Bythotrephes were numerous. Cisco (Coregonus artedi), a major nearshore and offshore species, fed largely on calanoid copepods, and selected calanoid copepods (spring) and Bythotrephes (summer and fall). Cisco also targeted prey similarly across bathymetric depths. Other major offshore fish species such as kiyi (Coregonus kiyi) and deepwater sculpin (Myoxocephalus thompsoni) fed largely on Mysis, with kiyi targeting Mysis exclusively while deepwater sculpin did not prefer any single prey organism. The major offshore predator siscowet lake trout (Salvelinus namaycush siscowet) consumed deepwater sculpin and coregonines, but selected deepwater sculpin and Mysis each season, with juveniles having a higher selection for Mysis than adults. Our results suggest that Mysis is not only a commonly consumed prey item, but a highly preferred prey item for pelagic, benthic, and piscivorous fishes in nearshore and offshore waters of Lake Superior.

  8. Increased predation of nutrient-enriched aposematic prey

    PubMed Central

    Halpin, Christina G.; Skelhorn, John; Rowe, Candy

    2014-01-01

    Avian predators readily learn to associate the warning coloration of aposematic prey with the toxic effects of ingesting them, but they do not necessarily exclude aposematic prey from their diets. By eating aposematic prey ‘educated’ predators are thought to be trading-off the benefits of gaining nutrients with the costs of eating toxins. However, while we know that the toxin content of aposematic prey affects the foraging decisions made by avian predators, the extent to which the nutritional content of toxic prey affects predators' decisions to eat them remains to be tested. Here, we show that European starlings (Sturnus vulgaris) increase their intake of a toxic prey type when the nutritional content is artificially increased, and decrease their intake when nutritional enrichment is ceased. This clearly demonstrates that birds can detect the nutritional content of toxic prey by post-ingestive feedback, and use this information in their foraging decisions, raising new perspectives on the evolution of prey defences. Nutritional differences between individuals could result in equally toxic prey being unequally predated, and might explain why some species undergo ontogenetic shifts in defence strategies. Furthermore, the nutritional value of prey will likely have a significant impact on the evolutionary dynamics of mimicry systems. PMID:24598424

  9. Increased predation of nutrient-enriched aposematic prey.

    PubMed

    Halpin, Christina G; Skelhorn, John; Rowe, Candy

    2014-04-22

    Avian predators readily learn to associate the warning coloration of aposematic prey with the toxic effects of ingesting them, but they do not necessarily exclude aposematic prey from their diets. By eating aposematic prey 'educated' predators are thought to be trading-off the benefits of gaining nutrients with the costs of eating toxins. However, while we know that the toxin content of aposematic prey affects the foraging decisions made by avian predators, the extent to which the nutritional content of toxic prey affects predators' decisions to eat them remains to be tested. Here, we show that European starlings (Sturnus vulgaris) increase their intake of a toxic prey type when the nutritional content is artificially increased, and decrease their intake when nutritional enrichment is ceased. This clearly demonstrates that birds can detect the nutritional content of toxic prey by post-ingestive feedback, and use this information in their foraging decisions, raising new perspectives on the evolution of prey defences. Nutritional differences between individuals could result in equally toxic prey being unequally predated, and might explain why some species undergo ontogenetic shifts in defence strategies. Furthermore, the nutritional value of prey will likely have a significant impact on the evolutionary dynamics of mimicry systems.

  10. Predator functional response changed by induced defenses in prey.

    PubMed

    Hammill, Edd; Petchey, Owen L; Anholt, Bradley R

    2010-12-01

    Functional responses play a central role in the nature and stability of predator-prey population dynamics. Here we investigate how induced defenses affect predator functional responses. In experimental communities, prey (Paramecium) expressed two previously undocumented inducible defenses--a speed reduction and a width increase--in response to nonlethal exposure to predatory Stenostomum. Nonlethal exposure also changed the shape of the predator's functional response from Type II to Type III, consistent with changes in the density dependence of attack rates. Handling times were also affected by prey defenses, increasing at least sixfold. These changes show that induced changes in prey have a real defensive function. At low prey densities, induction led to lower attack success; at high prey densities, attack rates were actually higher for induced prey. However, induction increased handling times sufficiently that consumption rates of defended prey were lower than those of undefended prey. Modification of attack rate and handling time has important potential consequences for population dynamics; Type III functional responses can increase the stability of population dynamics and persistence because predation on small populations is low, allowing a relict population to survive. Simulations of a predator-prey population dynamic model revealed the stabilizing potential of the Type III response.

  11. Concealed by conspicuousness: distractive prey markings and backgrounds

    PubMed Central

    Dimitrova, Marina; Stobbe, Nina; Schaefer, H. Martin; Merilaita, Sami

    2009-01-01

    High-contrast markings, called distractive or dazzle markings, have been suggested to draw and hold the attention of a viewer, thus hindering detection or recognition of revealing prey characteristics, such as the body outline. We tested this hypothesis in a predation experiment with blue tits (Cyanistes caeruleus) and artificial prey. We also tested whether this idea can be extrapolated to the background appearance and whether high-contrast markings in the background would improve prey concealment. We compared search times for a high-contrast range prey (HC-P) and a low-contrast range prey (LC-P) in a high-contrast range background (HC-B) and a low-contrast range background (LC-B). The HC-P was more difficult to detect in both backgrounds, although it did not match the LC-B. Also, both prey types were more difficult to find in the HC-B than in the LC-B, in spite of the mismatch of the LC-P. In addition, the HC-P was more difficult to detect, in both backgrounds, when compared with a generalist prey, not mismatching either background. Thus, we conclude that distractive prey pattern markings and selection of microhabitats with distractive features may provide an effective way to improve camouflage. Importantly, high-contrast markings, both as part of the prey coloration and in the background, can indeed increase prey concealment. PMID:19324754

  12. Coupled predator-prey oscillations in a chaotic food web.

    PubMed

    Benincà, Elisa; Jöhnk, Klaus D; Heerkloss, Reinhard; Huisman, Jef

    2009-12-01

    Coupling of several predator-prey oscillations can generate intriguing patterns of synchronization and chaos. Theory predicts that prey species will fluctuate in phase if predator-prey cycles are coupled through generalist predators, whereas they will fluctuate in anti-phase if predator-prey cycles are coupled through competition between prey species. Here, we investigate predator-prey oscillations in a long-term experiment with a marine plankton community. Wavelet analysis of the species fluctuations reveals two predator-prey cycles that fluctuate largely in anti-phase. The phase angles point at strong competition between the phytoplankton species, but relatively little prey overlap among the zooplankton species. This food web architecture is consistent with the size structure of the plankton community, and generates highly dynamic food webs. Continued alternations in species dominance enable coexistence of the prey species through a non-equilibrium 'killing-the-winner' mechanism, as the system shifts back and forth between the two predator-prey cycles in a chaotic fashion.

  13. [Optimization of the conditions for the immunochemical nephelometric analysis of IgG, IgA and IgM].

    PubMed

    Sorokina, N V; Zhuravleva, N I

    1990-01-01

    Immunonephelometric analysis (INA) is widely used in practical chemistry. the authors have examined the possibility of using Soviet reagents in an ICS Analyzer Beckman (USA) nephelometer. The effects of polyethylene glycol concentration, the reaction buffer pH and ionic strength on the results of INA were under study. Optimal conditions for INA with the test systems anti-IgA-IgA, anti-IgG-IgG, and anti-IgM-IgM with Soviet reagents have been developed. Lyophilized immunoreagents from the Mancini radial immunodiffusion kit, prepared at the N. F. Gamaleia Research Institute for Epidemiology and Microbiology, can be employed for analysis with this nephelometer.

  14. David and Goliath: potent venom of an ant-eating spider (Araneae) enables capture of a giant prey.

    PubMed

    Pekár, Stano; Šedo, Onřej; Líznarová, Eva; Korenko, Stanislav; Zdráhal, Zdeněk

    2014-07-01

    It is rare to find a true predator that repeatedly and routinely kills prey larger than itself. A solitary specialised ant-eating spider of the genus Zodarion can capture a relatively giant prey. We studied the trophic niche of this spider species and investigated its adaptations (behavioural and venomic) that are used to capture ants. We found that the spider captures mainly polymorphic Messor arenarius ants. Adult female spiders captured large morphs while tiny juveniles captured smaller morphs, yet in both cases ants were giant in comparison with spider size. All specimens used an effective prey capture strategy that protected them from ant retaliation. Juvenile and adult spiders were able to paralyse their prey using a single bite. The venom glands of adults were more than 50 times larger than those of juvenile spiders, but the paralysis latency of juveniles was 1.5 times longer. This suggests that this spider species possesses very potent venom already at the juvenile stage. Comparison of the venom composition between juvenile and adult spiders did not reveal significant differences. We discovered here that specialised capture combined with very effective venom enables the capture of giant prey.

  15. David and Goliath: potent venom of an ant-eating spider (Araneae) enables capture of a giant prey

    NASA Astrophysics Data System (ADS)

    Pekár, Stano; Šedo, Onřej; Líznarová, Eva; Korenko, Stanislav; Zdráhal, Zdeněk

    2014-07-01

    It is rare to find a true predator that repeatedly and routinely kills prey larger than itself. A solitary specialised ant-eating spider of the genus Zodarion can capture a relatively giant prey. We studied the trophic niche of this spider species and investigated its adaptations (behavioural and venomic) that are used to capture ants. We found that the spider captures mainly polymorphic Messor arenarius ants. Adult female spiders captured large morphs while tiny juveniles captured smaller morphs, yet in both cases ants were giant in comparison with spider size. All specimens used an effective prey capture strategy that protected them from ant retaliation. Juvenile and adult spiders were able to paralyse their prey using a single bite. The venom glands of adults were more than 50 times larger than those of juvenile spiders, but the paralysis latency of juveniles was 1.5 times longer. This suggests that this spider species possesses very potent venom already at the juvenile stage. Comparison of the venom composition between juvenile and adult spiders did not reveal significant differences. We discovered here that specialised capture combined with very effective venom enables the capture of giant prey.

  16. Deep-sea in situ observations of gonatid squid and their prey reveal high occurrence of cannibalism

    NASA Astrophysics Data System (ADS)

    Hoving, H. J. T.; Robison, B. H.

    2016-10-01

    In situ observations are rarely applied in food web studies of deep-sea organisms. Using deep-sea observations obtained by remotely operated vehicles in the Monterey Submarine Canyon, we examined the prey choices of more than 100 individual squids of the genus Gonatus. Off the California coast, these squids are abundant, semelparous (one reproductive cycle) oceanic predators but their diet has remained virtually unknown. Gonatus onyx and Gonatus berryi were observed to feed on mesopelagic fishes (in particular the myctophid Stenobrachius leucopsarus) as often as on squids but inter-specific differences in feeding were apparent. Gonatids were the most common squid prey and while cannibalism occurred in both species it was particularly high in Gonatus onyx (42% of all prey items). Typically, the size of prey was similar to the size of the predator but the squids were also seen to take much larger prey. Postjuvenile gonatids are opportunistic predators that consume nektonic members of the meso-and bathypelagic communities, including their own species. Such voracious feeding is likely necessary to support the high energetic demands associated with the single reproductive event; and for females the long brooding period during which they must depend on stored resources.

  17. Is Tetranychus urticae suitable prey for development and reproduction of naïve Coleomegilla maculata?

    PubMed

    Riddick, Eric W; Wu, Zhixin; Rojas, M Guadalupe

    2014-02-01

    The lady beetle Coleomegilla maculata De Geer is an omnivorous predator that could help suppress aphid and spider mite populations on plants in greenhouses, plantscapes or interiorscapes. We are assessing the nutritional requirements and feeding behavior of C. maculata on target prey (spider mites) and factitious (unnatural) food. Our ultimate goal is to develop an efficacious diet to mass produce C. maculata. In this study, we tested the hypothesis that Tetranychus urticae Koch (two-spotted spider mite) is not suitable prey for development and reproduction of naïve C. maculata (i.e., with no prior exposure to T. urticae). Our objectives were to (i) provide baseline data on the effects of consuming T. urticae on C. maculata life history, (ii) to compare the effects of consuming all stages of T. urticae versus eggs of Musca domestica L. (common housefly), and (iii) to determine if the consumption of plant products was beneficial. We used C. maculata from a colony reared only on Ephestia kuehniella Zeller (Mediterranean flour moth) eggs. In experiments, C. maculata larvae were reared from the first instar to adult stage with prey/food in replicated arenas; adult females were paired with a single male with prey/food. The results showed that naïve C. maculata readily attacked and consumed T. urticae. Nevertheless, T. urticae was less suitable than M. domestica eggs for C. maculata development and reproduction. Applying a synthetic pollen-Chlorella alga powder (SPCA) in arenas containing T. urticae appeared to boost C. maculata female development and reproduction.

  18. Ophthalmic manifestations in IgG4-related disease

    PubMed Central

    Ebbo, Mikael; Patient, Matthieu; Grados, Aurelie; Groh, Matthieu; Desblaches, Julien; Hachulla, Eric; Saadoun, David; Audia, Sylvain; Rigolet, Aude; Terrier, Benjamin; Perlat, Antoinette; Guillaud, Constance; Renou, Frederic; Bernit, Emmanuelle; Costedoat-Chalumeau, Nathalie; Harlé, Jean-Robert; Schleinitz, Nicolas

    2017-01-01

    Abstract IgG4-related disease (IgG4-RD) is characterized by variable tissue or organ involvements sharing common pathological findings. Orbital or orbital adnexa involvement of the disease has been reported in a few case series. The aim of our study was to characterize and analyze ophthalmic manifestations from a nationwide French case-series. Patients with IgG4-RD and orbital or orbital adnexa involvement included in the French multicentric IgG4-RD case-registry were identified. Only patients fulfilling “modified” comprehensive diagnostic criteria with pathological documentation were retained for the study. Clinical, biological, pathological, radiological findings and data regarding the response to treatment were retrospectively analyzed. According to our data registry, the frequency of IgG4-related ophthalmic disease (IgG4-ROD) was 17%. Mean age at diagnosis was 55.1 ± 7.1 years with a male/female ratio of 2.2. The 19 cases of IgG4-ROD consisted of lacrimal gland (68.4%), soft tissue (57.9%), extra-ocular muscles (36.8%), palpebral (21.1%), optical nerve (10.5%), orbital bone (10.5%), and mononeuritis (V1 and/or V2, 10.5%) involvements. IgG4-ROD was bilateral in 57.9% of cases. Extra-ophthalmic manifestations were reported in 78.9% of cases. All patients responded to prednisone but two-thirds of patients relapsed within a mean (SD) of 9.8 (3.5) months and 72.2% required long-term glucocorticoids and/or immunosuppressive agents. Eight patients were treated by rituximab with a favorable response in 87.5% of cases. Lacrimal involvement is the most frequent ophthalmic manifestation of IgG4-RD and is frequently associated with extra-orbital manifestations. Despite initial favorable response to steroids, the long-term management of relapsing patients needs to be improved. PMID:28272212

  19. A stage structured predator-prey model with disease in the prey

    NASA Astrophysics Data System (ADS)

    Agarwal, M.; Pandey, P.

    2008-02-01

    A non-linear mathematical model for a prey-predator community is proposed and analyzed. In the model, prey gets infected and predator population is structured into two stages of life, immature and mature with a time lag between two stages. Boundedness and non-negativity of the solutions of the system have been proved. Criterion for the stability of the system in the absence of delay is derived and bifurcation is found. The critical value of delay parameter for which stability change may occur is obtained.

  20. Use of sIgE/T-IgE in Predicting Systemic Reactions: Retrospective Analysis of 54 Honeybee Venom Allergy Cases in North China

    PubMed Central

    Guan, Kai; Li, Li-Sha; Yin, Jia

    2016-01-01

    Background: Venom allergy is significantly underestimated in China. Venom-specific IgE may not provide accurate clinical reactions. Our conducted retrospective analysis observes alternative diagnostic considerations in assessing confirmation and severity of honeybee venom allergy. Methods: Retrospective review of honeybee venom allergy versus nonallergy patients presented with positive honeybee venom (i1) sIgE results. According to clinically observed reactions caused by a honeybee sting, patients were divided into three groups. Patient residence and exposure types were analyzed. The sIgE/T-IgE among allergy and control groups was compared. Results: Gender ratio male:female was 32:22; median age was 39 years (31, 50). 48% (26/54) of patients live in urban areas, 52% (28/54) in rural areas. Based on bee sting reactions, patients were divided into common localized reactions (32/54), large localized reactions (7/54), and systemic reactions (15/54). In the systemic reaction group, patients presented as Type II (6/15), Type III (6/15). There is significant difference (P < 0.001) between the three groups in regards to exposure types. In the systemic reaction group, 8.7% (13/15) of patients are beekeepers. A significant difference (P < 0.001) was observed between allergic and control groups based on sIgE/T-IgE results. As well as significant difference observed between the systemic reaction group to the other two reaction groups in regards to sIgE/T-IgE results. Six systemic reaction patients presented with large localized reactions before onset of system symptoms 1 month to 1 year of being stung. Conclusions: Occupational exposure is the most common cause in honeybee venom allergy induced systemic reactions. The use of sIgE/T-IgE results is a useful diagnostic parameter in determining honeybee venom allergy. PMID:27569237

  1. Nonconsumptive predator-driven mortality causes natural selection on prey.

    PubMed

    Siepielski, Adam M; Wang, Jason; Prince, Garrett

    2014-03-01

    Predators frequently exert natural selection through differential consumption of their prey. However, predators may also cause prey mortality through nonconsumptive effects, which could cause selection if different prey phenotypes are differentially susceptible to this nonconsumptive mortality. Here we present an experimental test of this hypothesis, which reveals that nonconsumptive mortality imposed by predatory dragonflies causes selection on their damselfly prey favoring increased activity levels. These results are consistent with other studies of predator-driven selection, however, they reveal that consumption alone is not the only mechanism by which predators can exert selection on prey. Uncovering this mechanism also suggests that prey defensive traits may represent adaptations to not only avoid being consumed, but also for dealing with other sources of mortality caused by predators. Demonstrating selection through both consumptive and nonconsumptive predator mortality provides us with insight into the diverse effects of predators as an evolutionary force.

  2. The biomechanics of fast prey capture in aquatic bladderworts.

    PubMed

    Singh, Amit K; Prabhakar, Sunil; Sane, Sanjay P

    2011-08-23

    Carnivorous plants match their animal prey for speed of movements and hence offer fascinating insights into the evolution of fast movements in plants. Here, we describe the mechanics of prey capture in aquatic bladderworts Utricularia stellaris, which prey on swimming insect larvae or nematodes to supplement their nitrogen intake. The closed Utricularia bladder develops lower-than-ambient internal pressures by pumping out water from the bladder and thus setting up an elastic instability in bladder walls. When the external sensory trigger hairs on their trapdoor are mechanically stimulated by moving prey, the trapdoor opens within 300-700 μs, causing strong inward flows that trap their prey. The opening time of the bladder trapdoor is faster than any recorded motion in carnivorous plants. Thus, Utricularia have evolved a unique biomechanical system to gain an advantage over their animal prey.

  3. Egg Load Decreases Mobility and Increases Predation Risk in Female Black-Horned Tree Crickets (Oecanthus nigricornis)

    PubMed Central

    Ercit, Kyla; Martinez-Novoa, Andrew; Gwynne, Darryl T.

    2014-01-01

    Female-biased predation is an uncommon phenomenon in nature since males of many species take on riskier behaviours to gain more mates. Several species of sphecid wasps have been observed taking more female than male prey, and it is not fully understood why. The solitary sphecid Isodontia mexicana catches more adult female tree cricket (Oecanthus nigricornis) prey. Previous work has shown that, although female tree crickets are larger and thus likely to be more valuable as prey than males, body size alone cannot fully explain why wasps take more females. We tested the hypothesis that wasps catch adult female tree crickets more often because bearing eggs impedes a female’s ability to escape predation. We compared female survivors to prey of I. mexicana, and found that females carrying more eggs were significantly more likely to be caught by wasps, regardless of their body size and jumping leg mass. We also conducted laboratory experiments where females’ jumping responses to a simulated attack were measured and compared to her egg load and morphology. We found a significant negative relationship between egg load and jumping ability, and a positive relationship between body size and jumping ability. These findings support the hypothesis that ovarian eggs are a physical handicap that contributes to female-biased predation in this system. Predation on the most fecund females may have ecological-evolutionary consequences such as collapse of prey populations or selection for alternate life history strategies and behaviours. PMID:25330090

  4. IgG4-Related Hypophysitis: Case Report and Literature Review.

    PubMed

    Decker, Lauren; Crawford, Angela M; Lorenzo, Gamaliel; Stippler, Martina; Konstantinov, Konstantin N; SantaCruz, Karen

    2016-12-01

    IgG4-related hypophysitis is a rare, inflammatory process of the pituitary that mimics more commonly seen pituitary tumors. We report a case of IgG4-related hypophysitis in a 16-year-old female with diabetes insipidus who was found to have IgG4-related hypophysitis based on tissue diagnosis. This entity has not been previously described in a pediatric patient. Recognition of certain inflammatory processes of the pituitary may lead to alternative means of diagnosis and medical management without a biopsy.

  5. IgG4-Related Hypophysitis: Case Report and Literature Review

    PubMed Central

    Decker, Lauren; Crawford, Angela M; Lorenzo, Gamaliel; Stippler, Martina; Konstantinov, Konstantin N

    2016-01-01

    IgG4-related hypophysitis is a rare, inflammatory process of the pituitary that mimics more commonly seen pituitary tumors. We report a case of IgG4-related hypophysitis in a 16-year-old female with diabetes insipidus who was found to have IgG4-related hypophysitis based on tissue diagnosis. This entity has not been previously described in a pediatric patient. Recognition of certain inflammatory processes of the pituitary may lead to alternative means of diagnosis and medical management without a biopsy. PMID:28083451

  6. Levofloxacin Induced Toxic Epidermal Necrolysis: Successful Therapy with Omalizumab (Anti-IgE) and Pulse Prednisolone

    PubMed Central

    Uzun, Rusen; Yalcin, Arzu Didem; Celik, Betul; Bulut, Tangul; Yalcin, Ata Nevzat

    2016-01-01

    Patient: Female, 74 Final Diagnosis: Toxic epidermal necrolysis Symptoms: Bullous hemorrhagic lesions Medication: Levoflaxosine Clinical Procedure: Omalizumab therapy Specialty: Allergology Objective: Rare disease Background: Toxic epidermal necrolysis (TEN) is characterized by widespread erythematous and bullous lesions on the skin. Nowadays, considerable progress has been made in the understanding of its pathogenesis. Immunologically it is similar to graft-versus-host disease. Therefore, we may propose that TEN is a disorder of cell-mediated immunity. Case Report: Our patient was a 74-year-old white female who had pneumonia and was positive for hepatitis C virus (HCV), and who had been on levofloxacin therapy. After the first levofloxacin dose, erythematous dusky red macules occurred on her extremities and trunk, and on the following day, confluent purpuric lesions tended to run together over 85% of her body. Her biopsy results indicated TEN. Laboratory testing for serum ECP (eosinophil cationic peptide) and serum immunoglobulin (Ig) levels were performed, and blister fluid was investigated. The patient responded positively to omalizumab treatment and after treatment laboratory tests revealed decreased high sensitive CRP, ECP, IgG1, IgG2, IgG3, IgG4, IgA, and IgM levels. Conclusions: To the best of our knowledge, this is the first case of a patient with HCV who developed cutaneous adverse drug reaction on levofloxacin medication and recovered with omalizumab treatment. This is the first documentation of omalizumab treatment of a TEN patient. PMID:27634312

  7. The Neuronal Control of Flying Prey Interception in Dragonflies

    DTIC Science & Technology

    2014-08-19

    activity rotates the head as well in the direction opposite the preferred target direction. Two TSDNs also move the legs and mouthparts. Insect ...flight, Prey interception, Insect vision, Receptive field, Dragonfly U U U UU 0 Robert M. Olberg 518 388 6509 THE NEURONAL CONTROL OF FLYING PREY...reconstruct, in 3D, the flight trajectory of an aerial predator (killer fly: C. attenuata) and its potential prey (small flying insects such as fungus gnats

  8. Prey selectivity affects reproductive success of a corallivorous reef fish.

    PubMed

    Brooker, Rohan M; Jones, Geoffrey P; Munday, Philip L

    2013-06-01

    Most animals consume a narrower range of food resources than is potentially available in the environment, but the underlying basis for these preferences is often poorly understood. Foraging theory predicts that prey selection should represent a trade-off between prey preferences based on nutritional value and prey availability. That is, species should consume preferred prey when available, but select less preferred prey when preferred prey is rare. We employed both field observation and laboratory experiments to examine the relationship between prey selection and preferences in the obligate coral-feeding filefish, Oxymonacanthus longirostris. To determine the drivers of prey selection, we experimentally established prey preferences in choice arenas and tested the consequences of prey preferences for key fitness-related parameters. Field studies showed that individuals fed almost exclusively on live corals from the genus Acropora. While diet was dominated by the most abundant species, Acropora nobilis, fish appeared to preferentially select rarer acroporids, such as A. millepora and A. hyacinthus. Prey choice experiments confirmed strong preferences for these corals, suggesting that field consumption is constrained by availability. In a longer-term feeding experiment, reproductive pairs fed on non-preferred corals exhibited dramatic reductions to body weight, and in hepatic and gonad condition, compared with those fed preferred corals. The majority of pairs fed preferred corals spawned frequently, while no spawning was observed for any pairs fed a non-preferred species of coral. These experiments suggest that fish distinguish between available corals based on their intrinsic value as prey, that reproductive success is dependent on the presence of particular coral species, and that differential loss of preferred corals could have serious consequences for the population success of these dietary specialists.

  9. Birds of Prey: Training Solutions to Human Factors Issues

    DTIC Science & Technology

    2007-11-01

    Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC) 2007 2007 Paper No. 7133 Page 1 of 12 Birds of Prey: Training...2007 2. REPORT TYPE Conference Proceedings 3. DATES COVERED 01-01-2006 to 30-11-2007 4. TITLE AND SUBTITLE Birds of Prey: Training Solutions...ITSEC) 2007 2007 Paper No. 7133 Page 3 of 12 Birds of Prey: Training Solutions to Human Factors Issues Robert T. Nullmeyer Air Force Research

  10. Nash Equilibria in Noncooperative Predator-Prey Games

    SciTech Connect

    Ramos, Angel Manuel Roubicek, Tomas

    2007-09-15

    A noncooperative game governed by a distributed-parameter predator-prey system is considered, assuming that two players control initial conditions for predator and prey, respectively. Existence of a Nash equilibrium is shown under the condition that the desired population profiles and the environmental carrying capacity for the prey are sufficiently small. A conceptual approximation algorithm is proposed and analyzed. Finally, numerical simulations are performed, too.

  11. A delayed prey-predator system with parasitic infection.

    PubMed

    Mukherjee, Debasis

    2006-08-01

    This paper analyzes a prey-predator system in which some members of the prey population and all predators are subjected to infection by a parasite. The predator functional response is a function of a weighted sum of prey abundances. Persistence and extinction criteria are derived. The stability of the interior equilibrium point is discussed. The role of delay is also addressed. Lastly the results are verified through computer simulation. Numerical simulation suggests that the delay has a destabilizing effect.

  12. Prey Selection of Scandinavian Wolves: Single Large or Several Small?

    PubMed Central

    Eklund, Ann; Zimmermann, Barbara; Wikenros, Camilla; Wabakken, Petter

    2016-01-01

    Research on large predator-prey interactions are often limited to the predators’ primary prey, with the potential for prey switching in systems with multiple ungulate species rarely investigated. We evaluated wolf (Canis lupus) prey selection at two different spatial scales, i.e., inter- and intra-territorial, using data from 409 ungulate wolf-kills in an expanding wolf population in Scandinavia. This expansion includes a change from a one-prey into a two-prey system with variable densities of one large-sized ungulate; moose (Alces alces) and one small-sized ungulate; roe deer (Capreolus capreolus). Among wolf territories, the proportion of roe deer in wolf kills was related to both pack size and roe deer density, but not to moose density. Pairs of wolves killed a higher proportion of roe deer than did packs, and wolves switched to kill more roe deer as their density increased above a 1:1 ratio in relation to the availability of the two species. At the intra-territorial level, wolves again responded to changes in roe deer density in their prey selection whereas we found no effect of snow depth, time during winter, or other predator-related factors on the wolves’ choice to kill moose or roe deer. Moose population density was only weakly related to intra-territorial prey selection. Our results show that the functional response of wolves on moose, the species hitherto considered as the main prey, was strongly dependent on the density of a smaller, alternative, ungulate prey. The impact of wolf predation on the prey species community is therefore likely to change with the composition of the multi-prey species community along with the geographical expansion of the wolf population. PMID:28030549

  13. Distinct histopathological features of Hashimoto's thyroiditis with respect to IgG4-related disease.

    PubMed

    Li, Yaqiong; Zhou, Gengyin; Ozaki, Takashi; Nishihara, Eijun; Matsuzuka, Fumio; Bai, Yanhua; Liu, Zhiyan; Taniguchi, Emiko; Miyauchi, Akira; Kakudo, Kennichi

    2012-08-01

    A form of Hashimoto's thyroiditis with lymphoplasmacytic sclerosing changes and increased numbers of IgG4-positive plasma cells has recently been reported in the literature. These histopathological features suggest that this subtype of Hashimoto's thyroiditis may be closely related to IgG4-related disease. Therefore, this unique form of IgG4-related Hashimoto's thyroiditis, which is referred to as IgG4 thyroiditis, has its own clinical, serological, and sonographic features that are distinct from those associated with non-IgG4 thyroiditis. IgG4 thyroiditis shares similarities with the well-known fibrous variant of Hashimoto's thyroiditis; however, the detailed histopathological features of IgG4 thyroiditis have not been well established. Based on immunostaining results, 105 patients with Hashimoto's thyroiditis were divided into an IgG4 thyroiditis group (n=28) and a non-IgG4 thyroiditis group (n=77). As in our previous reports, IgG4 thyroiditis was associated with a patient population of a younger age, a lower female-to-male ratio, rapid progression, higher levels of thyroid autoantibodies, subclinical hypothyroidism, and diffuse sonographic echogenicity. Histopathologically, this group revealed severe lymphoplasmacytic infiltration, dense stromal fibrosis, marked follicular cell degeneration, numerous micro-follicles, and notable giant cell/histiocyte infiltration. Importantly, the IgG4-related group did not completely overlap with fibrous variant of Hashimoto's thyroiditis. Four cases (14%) in the IgG4 thyroiditis group presented only mild fibrosis in the stroma, whereas 29 cases (38%) in the non-IgG4 thyroiditis group met the diagnostic criteria for fibrous variant of Hashimoto's thyroiditis. Furthermore, we observed three patterns of stromal fibrosis in Hashimoto's thyroiditis: interfollicular fibrosis, interlobular fibrosis, and scar fibrosis. The IgG4 thyroiditis group was significantly associated with the presence of predominant interfollicular fibrosis. In

  14. Female circumcision.

    PubMed

    Abu Daia, J M

    2000-10-01

    It is uncertain when female circumcision was first practiced, but it certainly preceded the founding of both Christianity and Islam. A review of past and current historical, popular and professional literature was undertaken, and 4 types of female circumcision were identified. Typically female circumcision is performed by a local village practitioner, lay person or by untrained midwives. Female genital mutilation is not accepted by any religious or medical opinion, and is a violation of human rights against helpless individuals who are unable to provide informed consent and who must therefore be protected through education and legislation. Complications of female circumcision can present after many years. Any medical practitioner (either for adult or pediatric) can be confronted with this issue of female circumcision, even in countries where this custom is not present, thus mandating the understanding of this complex issue.

  15. Prey processing in the Siamese fighting fish (Betta splendens).

    PubMed

    Konow, Nicolai; Krijestorac, Belma; Sanford, Christopher P J; Boistel, Renauld; Herrel, Anthony

    2013-07-01

    We studied prey processing in the Siamese fighting fish (Betta splendens), involving slow, easily observed head-bobbing movements, which were compared with prey processing in other aquatic feeding vertebrates. We hypothesized that head-bobbing is a unique prey-processing behaviour, which alternatively could be structurally and functionally analogous with raking in basal teleosts, or with pharyngognathy in neoteleosts. Modulation of head-bobbing was elicited by prey with different motility and toughness. Head-bobbing involved sustained mouth occlusion and pronounced cranial elevation, similar to raking. However, the hyoid and pectoral girdle were protracted, and not retracted as in both raking and pharyngognathy. High-speed videofluoroscopy of hyoid movements confirmed that head-bobbing differs from other known aquatic prey-processing behaviours. Nevertheless, head-bobbing and other prey-processing behaviours converge on a recurrent functional theme in the trophic ecology of aquatic feeding vertebrates; the use of intraoral and oropharyngeal dentition surfaces to immobilize, reduce and process relatively large, tough or motile prey. Prey processing outside the pharyngeal region has not been described for neoteleosts previously, but morphological evidence suggests that relatives of Betta might use similar processing behaviours. Thus, our results suggest that pharyngognathy did not out-compete ancestral prey-processing mechanisms completely during the evolution of neoteleosts.

  16. Prey community structure affects how predators select for Mullerian mimicry.

    PubMed

    Ihalainen, Eira; Rowland, Hannah M; Speed, Michael P; Ruxton, Graeme D; Mappes, Johanna

    2012-06-07

    Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits (Parus major) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mortality in complex communities when the birds were inexperienced. However, in a subsequent generalization test to potential mimics of the model prey (a continuum of signal accuracy), only birds that had foraged from simple communities selected against inaccurate mimics. Therefore, accurate mimicry is more likely to evolve in simple communities even though predator avoidance learning is slower in complex communities. For mimicry to evolve, prey species must have a common predator; the effective community consists of the predator's diet. In diverse environments, the limited diets of specialist predators could create 'simple community pockets' where accurate mimicry is selected for.

  17. Model of naticid gastropod predator-prey coevolution

    SciTech Connect

    DeAngelis, D.L.; Kitchell, J.A.; Post, W.M.; Travis, C.C.

    1982-01-01

    Size change over evolutionary time between two interacting species, a predatory naticid gastropod and its bivalve prey, is analyzed. We show that two simultaneous, maximizing algorithms (the predator maximizes energy intake; the prey maximizes reproductive output) result in an endogenous, coevolutionary size increase, to a stable attracting point. In particular, we show that selection for delayed reproduction in a predatorpreay system that is highly size-selective due to the predatory strategy of cost-benefit prey selection, coupled with the relative allometries of cost (prey shell thickness) and benefit (prey biomass) with prey size, and the highly size-dependent probability of successful predation, lead to a coevolutionary size increase for both predator and prey, up to a limit condition dictated by predatory respiration costs. In the absence of predation, the prey species attains a smaller size than in the presence of predation. Addition of the predator results in a delay in the timing of reproduction by the prey, thereby facilitating a size response.

  18. A study of prey-predator relations for mammals.

    PubMed

    Khan, Q J A; Ghaleb, A F

    2003-07-21

    In this paper, we present a prey-predator nonlinear model for mammals, consisting of large- and small-size prey species with group defence, in a partially protected habitat. If the prey size is small, then it is more prone to the predator at higher densities. Conversely, large prey size at higher densities tend to develop group defence. Therefore, the predator will be attracted towards that area where prey are less in number. A new physical constant has been introduced into the radiation-type condition on that part of the boundary where interaction between prey and predator takes place. This constant allows us to efficiently model group defence capabilities of the herds and its numerical values have to be determined for different pairs of prey-predator species from field observations. A way of measuring the constants involved in the model is suggested. Numerical results are provided and thoroughly discussed for a habitat of circular shape. The obtained results show that in the region away from the protected area, the density of large-size prey species is higher than that of small-size prey species, a fact that is in accordance with observations.

  19. Prey depletion as a threat to the world's large carnivores

    PubMed Central

    Ripple, William J.

    2016-01-01

    Large terrestrial carnivores are an ecologically important, charismatic and highly endangered group of species. Here, we assess the importance of prey depletion as a driver of large carnivore endangerment globally using lists of prey species for each large carnivore compiled from the literature. We consider spatial variation in prey endangerment, changes in endangerment over time and the causes of prey depletion, finding considerable evidence that loss of prey base is a major and wide-ranging threat among large carnivore species. In particular, the clouded leopard (Neofelis nebulosa), Sunda clouded leopard (Neofelis diardi), tiger (Panthera tigris), dhole (Cuon alpinus) and Ethiopian wolf (Canis simensis) all have at least 40% of their prey classified as threatened on the International Union for the Conservation of Nature (IUCN) Red List and, along with the leopard (Panethra pardus), all of these species except the Ethiopian wolf have at least 50% of their prey classified as declining. Of the 494 prey species in our analysis, an average of just 6.9% of their ranges overlap protected areas. Together these results show the importance of a holistic approach to conservation that involves protecting both large carnivores directly and the prey upon which they depend. PMID:27853599

  20. Alternative prey use affects helminth parasite infections in grey wolves.

    PubMed

    Friesen, Olwyn C; Roth, James D

    2016-09-01

    Predators affect prey populations not only through direct predation, but also by acting as definitive hosts for their parasites and completing parasite life cycles. Understanding the affects of parasitism on prey population dynamics requires knowing how their predators' parasite community is affected by diet and prey availability. Ungulates, such as moose (Alces americanus) and white-tailed deer (Odocoileus virginianus), are often important prey for wolves (Canis lupus), but wolves also consume a variety of alternative prey, including beaver (Castor canadensis) and snowshoe hare (Lepus americanus). The use of alternative prey, which may host different or fewer parasites than ungulates, could potentially reduce overall abundance of ungulate parasites within the ecosystem, benefiting both wolves and ungulate hosts. We examined parasites in wolf carcasses from eastern Manitoba and estimated wolf diet using stable isotope analysis. Taeniidae cestodes were present in most wolves (75%), reflecting a diet primarily comprised of ungulates, but nematodes were unexpectedly rare. Cestode abundance was negatively related to the wolf's δ(13) C value, indicating diet affects parasite abundance. Wolves that consumed a higher proportion of beaver and caribou (Rangifer tarandus), estimated using Bayesian mixing models, had lower cestode abundance, suggesting the use of these alternative prey can reduce parasite loads. Long-term consumption of beavers may lower the abundance of adult parasites in wolves, eventually lowering parasite density in the region and ultimately benefiting ungulates that serve as intermediate hosts. Thus, alternative prey can affect both predator-prey and host-parasite interactions and potentially affect food web dynamics.

  1. Risky prey behavior evolves in risky habitats.

    PubMed

    Urban, Mark C

    2007-09-04

    Longstanding theory in behavioral ecology predicts that prey should evolve decreased foraging rates under high predation threat. However, an alternative perspective suggests that growth into a size refuge from gape-limited predation and the future benefits of large size can outweigh the initial survival costs of intense foraging. Here, I evaluate the relative contributions of selection from a gape-limited predator (Ambystoma opacum) and spatial location to explanations of variation in foraging, growth, and survival in 10 populations of salamander larvae (Ambystoma maculatum). Salamander larvae from populations naturally exposed to intense A. opacum predation risk foraged more actively under common garden conditions. Higher foraging rates were associated with low survival in populations exposed to free-ranging A. opacum larvae. Results demonstrate that risky foraging activity can evolve in high predation-risk habitats when the dominant predators are gape-limited. This finding invites the further exploration of diverse patterns of prey foraging behavior that depends on natural variation in predator size-selectivity. In particular, prey should adopt riskier behaviors under predation threat than expected under existing risk allocation models if foraging effort directly reduces the duration of risk by growth into a size refuge. Moreover, evidence from this study suggests that foraging has evolved over microgeographic scales despite substantial modification by regional gene flow. This interaction between local selection and spatial location suggests a joint role for adaptation and maladaptation in shaping species interactions across natural landscapes, which is a finding with implications for dynamics at the population, community, and metacommunity levels.

  2. The Coevolution of "Tyrannosaurus" & Its Prey: Could "Tyrannosaurus" Chase down & Kill a "Triceratops" for Lunch?

    ERIC Educational Resources Information Center

    May, S. Randolph

    2014-01-01

    Students will analyze the coevolution of the predator-prey relationships between "Tyrannosaurus rex" and its prey species using analyses of animal speeds from fossilized trackways, prey-animal armaments, adaptive behaviors, bite marks on prey-animal fossils, predator-prey ratios, and scavenger competition. The students will be asked to…

  3. Predation: Prey plumage adaptation against falcon attack.

    PubMed

    Palleroni, Alberto; Miller, Cory T; Hauser, Marc; Marler, Peter

    2005-04-21

    Several plumage types are found in feral pigeons (Columba livia), but one type imparts a clear survival advantage during attacks by the swiftest of all predators--the peregrine falcon (Falco peregrinus). Here we use quantitative field observations and experiments to demonstrate both the selective nature of the falcon's choice of prey and the effect of plumage coloration on the survival of feral pigeons. This plumage colour is an independently heritable trait that is likely to be an antipredator adaptation against high-speed attacks in open air space.

  4. A new sensitive and specific enzyme-linked immunosorbent assay for IgD.

    PubMed

    Mosedale, David E; Sandhu, Manjinder S; Luan, Jian'an; Goodall, Margaret; Grainger, David J

    2006-06-30

    We have developed a new highly specific ELISA for IgD, and then used it to measure levels of circulating IgD in the serum of 480 un-selected patients from the East Anglia region of UK. The assay is both extremely sensitive and specific, with a minimum detected IgD concentration of 30 pg/ml and more than 10,000-fold specificity for IgD over all other human immunoglobulins. The assay shows linear dilution characteristics with both purified IgD and human serum, and spiking of purified IgD into either purified immunoglobulins or human serum shows c. 100% recovery. Furthermore, intra-assay and inter-assay coefficients of variation for repeated measurements of the same samples are below 10% and 15% respectively. Measurement of IgD levels on the un-selected patient population showed levels to range from <300 pg/ml to over 100 microg/ml, with a geometric mean of 8 microg/ml. The distribution is approximately normal after log transformation. Levels of circulating IgD were higher in men than in women. There was a significant negative correlation between levels of IgD and age in women, but not in men. Moreover, after adjustment for age and sex, there were statistically significantly higher levels of circulating IgD in male (but not female) smokers, compared to their non-smoking counterparts. These results highlight the care that needs to be taken to control for age, sex and cigarette smoking when examining levels of circulating IgD in future studies.

  5. IgA deficiency in wolves.

    PubMed

    Frankowiack, Marcel; Hellman, Lars; Zhao, Yaofeng; Arnemo, Jon M; Lin, Miaoli; Tengvall, Katarina; Møller, Torsten; Lindblad-Toh, Kerstin; Hammarström, Lennart

    2013-06-01

    Low mean concentrations of serum immunoglobulin A (IgA) and an increased frequency of overt IgA deficiency (IgAD) in certain dog breeds raises the question whether it is a breeding-enriched phenomenon or a legacy from the dog's ancestor, the gray wolf (Canis lupus). The IgA concentration in 99 serum samples from 58 free-ranging and 13 captive Scandinavian wolves, was therefore measured by capture ELISA. The concentrations were markedly lower in the wolf serum samples than in the dog controls. Potential differences in the IgA molecule between dogs and wolves were addressed by sequencing the wolf IgA heavy chain constant region encoding gene (IGHA). Complete amino acid sequence homology was found. Detection of wolf and dog IgA was ascertained by showing identity using double immunodiffusion. We suggest that the vast majority of wolves, the ancestor of the dog, are IgA deficient.

  6. IgG subclasses to food antigens.

    PubMed

    Quinti, I; Papetti, C; D'Offizi, G; Cavagni, G; Panchor, M L; Lunardi, C; Paganelli, R

    1988-02-01

    Involvement of sub-classes of IgG that are specific for food allergens in anaphylactoid reactions and some manifestations of atopy no longer needs to be shown. Accordingly, sub-classes of IgG specific for ovalbumin (OVA) and beta-lactoglobulin (BLG) were compared in healthy subjects and those who presented with an intolerance or food allergy to OVA and BLG to decide whether a restrictive diet was necessary. The four sub-classes of IgG1, IgG2, IgG3 and IgG4 were isolated in all the groups. IgG4 was highest in the allergic subjects and the IgG sub-class values were modified by the diet differently in each group. Unfortunately, the small number of subjects does not allow the formation of a definite conclusion to this study.

  7. Global existence of solutions and uniform persistence of a diffusive predator-prey model with prey-taxis

    NASA Astrophysics Data System (ADS)

    Wu, Sainan; Shi, Junping; Wu, Boying

    2016-04-01

    This paper proves the global existence and boundedness of solutions to a general reaction-diffusion predator-prey system with prey-taxis defined on a smooth bounded domain with no-flux boundary condition. The result holds for domains in arbitrary spatial dimension and small prey-taxis sensitivity coefficient. This paper also proves the existence of a global attractor and the uniform persistence of the system under some additional conditions. Applications to models from ecology and chemotaxis are discussed.

  8. Linking biomechanics and ecology through predator-prey interactions: flight performance of dragonflies and their prey.

    PubMed

    Combes, S A; Rundle, D E; Iwasaki, J M; Crall, J D

    2012-03-15

    Aerial predation is a highly complex, three-dimensional flight behavior that affects the individual fitness and population dynamics of both predator and prey. Most studies of predation adopt either an ecological approach in which capture or survival rates are quantified, or a biomechanical approach in which the physical interaction is studied in detail. In the present study, we show that combining these two approaches provides insight into the interaction between hunting dragonflies (Libellula cyanea) and their prey (Drosophila melanogaster) that neither type of study can provide on its own. We performed >2500 predation trials on nine dragonflies housed in an outdoor artificial habitat to identify sources of variability in capture success, and analyzed simultaneous predator-prey flight kinematics from 50 high-speed videos. The ecological approach revealed that capture success is affected by light intensity in some individuals but that prey density explains most of the variability in success rate. The biomechanical approach revealed that fruit flies rarely respond to approaching dragonflies with evasive maneuvers, and are rarely successful when they do. However, flies perform random turns during flight, whose characteristics differ between individuals, and these routine, erratic turns are responsible for more failed predation attempts than evasive maneuvers. By combining the two approaches, we were able to determine that the flies pursued by dragonflies when prey density is low fly more erratically, and that dragonflies are less successful at capturing them. This highlights the importance of considering the behavior of both participants, as well as their biomechanics and ecology, in developing a more integrative understanding of organismal interactions.

  9. Analysis of a competitive prey-predator system with a prey refuge.

    PubMed

    Sarwardi, Sahabuddin; Mandal, Prashanta Kumar; Ray, Santanu

    2012-12-01

    Gauss's competitive exclusive principle states that two competing species having analogous environment cannot usually occupy the same space at a time but in order to exploit their common environment in a different manner, they can co-exist only when they are active in different times. On the other hand, several studies on predators in various natural and laboratory situations have shown that competitive coexistence can result from predation in a way by resisting any one prey species from becoming sufficiently abundant to outcompete other species such that the predator makes the coexistence possible. It has also been shown that the use of refuges by a fraction of the prey population exerts a stabilizing effect in the interacting population dynamics. Further, the field surveys in the Sundarban mangrove ecosystem reveal that two detritivorous fishes, viz. Liza parsia and Liza tade (prey population) coexist in nature with the presence of the predator fish population, viz. Lates calcarifer by using refuges. In view of such observations in mind, a three-component model consisting of two prey and one predator population is considered in the present investigation with the inclusion of Holling type-II response function incorporating a constant proportion of prey refuge. The essential mathematical features of the present model have been analyzed thoroughly in terms of the local and the global stability and the bifurcations arising in some selected situations as well. The threshold values for some parameters indicating the feasibility and the stability conditions of some equilibria are also determined. The ranges of the significant parameters under which the system admits a Hopf bifurcation are investigated. The explicit formulae for determining the stability, direction and other properties of bifurcating periodic solutions are also derived with the use of both the normal form and the central manifold theory. Numerical illustrations are performed finally in order to validate

  10. Transchromosomally derived Ig heavy chains

    SciTech Connect

    Knight, K.L.; Kingzette, M.; Crane, M.A.

    1995-07-15

    During an immune response, activated B cells undergo isotype switching and begin to express isotypes other than IgM and IgD. Isotype switching occurs when downstream C{gamma}, C{alpha}, or C{epsilon} genes are rearranged into the S{mu} chromosomal region, resulting in the deletion of the region in between. These rearrangements usually occur in cis, i.e., intrachromosomally. In previous studies, we analyzed allotypic specificities of rabbit secretory IgA and identified a substantial number of IgA heavy chains with V{sub h} and C{alpha} allotypes that were encoded by V{sub h} and C{alpha} genes in trans. In those studies, however, we could not determine whether the trans association of V{sub H} and C{alpha} occurred during VDJ gene rearrangement or during isotype switching. Here, we cloned rabbit cDNA which encodes these trans IgA heavy chains and determined the chromosomal origin of the V{sub H}, J{sub H}, and C{alpha} regions. To determine whether the trans association occurred during VDJ gene rearrangement, we analyzed the nucleotide polymorphism of the J{sub H} region and the V{sub H} allotype encoded by the cDNA. We found that the V{sub H} and J{sub H} genes used in the VDJ gene rearrangements were from the same chromosome, indicating that the V{sub H}, D, and J{sub H} gene rearrangements occurred in cis. Furthermore, we analyzed the DNA polymorphisms of J{sub H} and C{alpha} and showed that the VDJ and C{alpha} genes encoding the trans IgA molecules were derived from different parental chromosomes. We suggest that the trans association occurred during isotype switching. This study shows that V{sub H} and C{sub H} can associate transchromosomally as part of a normal immune response. 34 refs., 5 figs.

  11. IgG4-related kidney disease.

    PubMed

    Cornell, Lynn D

    2012-11-01

    IgG4-related kidney disease is a term that refers to any form of renal involvement by IgG4-related disease (IgG4-RD), a recently recognized systemic immune-mediated disease. The most common renal manifestation is IgG4-related tubulointerstitial nephritis (IgG4-TIN), which presents as acute or chronic renal insufficiency, renal mass lesions, or both. On biopsy, IgG4-TIN shows a plasma cell-rich interstitial inflammatory infiltrate with increased IgG4+ plasma cells, along with expansile interstitial fibrosis; tubular basement membrane immune complex deposits are common. IgG4-TIN usually shows a brisk response to immunosuppressive therapy. Glomeruli may be affected by IgG4-RD, usually in the form of membranous glomerulonephritis. Other patterns of glomerular disease include IgA nephropathy, membranoproliferative glomerulonephritis, and endocapillary or mesangioproliferative immune complex glomerulonephritis. IgG4-related plasma cell arteritis has also been observed in the kidney. This review describes the histopathologic and immunophenotypic patterns of renal involvement by IgG4-RD, with associated clinical, radiographic, and serologic features.

  12. Oxidative stress in IgA nephropathy.

    PubMed

    Coppo, R; Camilla, R; Amore, A; Peruzzi, L

    2010-01-01

    IgA nephropathy (IgAN) is characterized by mesangial deposits of IgA1, likely due to accumulation of IgA immune complexes. The activation of intracellular signaling mostly results in oxidative stress, as detected in mesangial cells cultured with aberrantly glycosylated IgA or IgA aggregates and in renal biopsies of patients with IgAN. Signs of altered oxidation/antioxidation balance have been detected in sera and/or in erythrocytes of patients with IgAN, including increased levels of lipoperoxide or malondialdehyde and reduced activity of superoxide dismutase, catalase and glutathione peroxidase. Moreover, increased levels of a marker of oxidative stress, advanced oxidation protein products (AOPPs), have been reported to be significantly associated with proteinuria and disease progression in patients with IgAN. AOPPs are often carried by albumin and can in turn enhance the oxidative stress in the circulation. Recent research suggests that the nephrotoxicity of aberrantly glycosylated IgA1 in IgAN is enhanced in the presence of systemic signs of oxidative stress, and it is tempting to hypothesize that the level of the oxidative milieu conditions the different expression and progression of IgAN.

  13. Evaluating prey switching in wolf-ungulate systems.

    PubMed

    Garrott, Robert A; Bruggeman, Jason E; Becker, Matthew S; Kalinowski, Steven T; White, P J

    2007-09-01

    Wolf restoration has become a widely accepted conservation and management practice throughout North America and Europe, though the ecosystem effects of returning top carnivores remain both scientific and societal controversies. Mathematical models predicting and describing wolf-ungulate interactions are typically limited to the wolves' primary prey, with the potential for prey switching in wolf-multiple-ungulate systems only suggested or assumed by a number of investigators. We used insights gained from experiments on small taxa and field data from ongoing wolf-ungulate studies to construct a model of predator diet composition for a wolf-elk-bison system in Yellowstone National Park, Wyoming, USA. The model explicitly incorporates differential vulnerability of the ungulate prey types to predation, predator preference, differences in prey biomass, and the possibility of prey switching. Our model demonstrates wolf diet shifts with changes in relative abundance of the two prey, with the dynamics of this shift dependent on the combined influences of preference, differential vulnerability, relative abundances of prey, and whether or not switching occurs. Differences in vulnerability between elk and bison, and strong wolf preference for elk, result in an abrupt dietary shift occurring only when elk are very rare relative to bison, whereas incorporating switching initiates the dietary shift more gradually and at higher bison-elk ratios. We demonstrate how researchers can apply these equations in newly restored wolf-two-prey systems to empirically evaluate whether prey switching is occurring. Each coefficient in the model has a biological interpretation, and most can be directly estimated from empirical data collected from field studies. Given the potential for switching to dramatically influence predator-prey dynamics and the wide range of expected prey types and abundances in some systems where wolves are present and/or being restored, we suggest that this is an

  14. Functional responses: a question of alternative prey and predator density.

    PubMed

    Tschanz, Britta; Bersier, Louis-Felix; Bacher, Sven

    2007-05-01

    Throughout the study of ecology, there has been a growing realization that indirect effects among species cause complexity in food webs. Understanding and predicting the behavior of ecosystems consequently depends on our ability to identify indirect effects and their mechanisms. The present study experimentally investigates indirect interactions arising between two prey species that share a common predator. In a natural field experiment, we introduced different densities of mealworms (Tenebrio molitor), an alternative prey, to a previously studied predator-prey system in which paper wasps (Polistes dominulus) preyed on shield beetle larvae (Cassida rubiginosa). We tested if alternative prey affects predation on the first prey (i.e., the predator-dependent functional response of paper wasps) by modifying either interference among predators or the effective number of predators foraging on shield beetles. Presence of mealworms significantly reduced the effective number of predators, whereas predator interference was not affected. In this way, the experimentally introduced alternative prey altered the wasps' functional response and thereby indirectly influenced C. rubiginosa density. In all prey-density combinations offered, paper wasps constantly preferred T. molitor. This led to an asymmetrical, indirect interaction between both prey species: an increase in mealworm density significantly relaxed predation on C. rubiginosa, whereas an increase in C. rubiginosa density intensified predation on mealworms. Such asymmetrical outcomes of a fixed food preference can significantly affect the population dynamics of the species involved. In spite of the repeated finding of a Type III functional response in this system, our experiment did not reveal switching behavior in paper wasps. The variety of mechanisms underlying direct and indirect interactions within our study system exemplifies the importance of incorporating alternative prey when investigating the impact of a

  15. Insect prey foraging strategies in Callicebus oenanthe in northern Peru.

    PubMed

    Deluycker, Anneke M

    2012-05-01

    Titi monkeys (genus Callicebus) are small-bodied platyrrhines that supplement their predominantly frugivorous diet with variable amounts of leaves, seeds, and/or arthropod prey. Notable interspecific variation in the amount of insect prey in the diet has been observed in Callicebus, ranging from 0% to 20%. In this study, I investigate the degree and type of prey foraging in a little-known species, Callicebus oenanthe inhabiting a fragmented, secondary forest on the foothills of the Andes in northern Peru. I present data on prey type, prey search and capture techniques, substrate/vegetation use, foraging height, prey capture efficiency, and seasonal variation of insect prey foraging in one group of C. oenanthe observed from January to August 2005. Insect prey accounted for 22% of the diet, the highest amount reported for any Callicebus species to date, and insects from at least six different orders were included. C. oenanthe was mainly an investigative forager of hidden prey, manipulating easy-to-open substrates such as rolled up leaves, and hunted ant swarms and larger insects opportunistically. Insect foraging was predominant during the dry season (26%) and decreased during the wet season (13%). The study group foraged mostly in the understory (2-6 m) within vine-laden shrubs and trees, which may conform to an anti-predator strategy of crypticity. Overall the group had an 83% insect capture success rate. These data suggest that insect prey is an important part of the diet of C. oenanthe and may be especially notable during periods of resource scarcity. This study adds to the knowledge concerning insect prey foraging in Callicebus, which can have an important role in defining ecological strategies in the selection of secondary protein food resources within a given ecosystem.

  16. IgA1 dominant subclass of latent IgA mesangial deposition in donated kidney

    PubMed Central

    Oka, Kazumasa; Nishimura, Kenji; Kishikawa, Hidefumi; Ichikawa, Yasuji

    2016-01-01

    Background In the pathogenesis of immunoglobulin A nephropathy (IgAN), the IgA1 subclass is more important than the IgA2 subclass. In healthy men, the prevalence of mesangial IgA deposition has been previously investigated. However, it remains unknown whether the presence of urinary abnormalities depends on the subclass of IgA deposition. Materials and methods We researched the subclasses of IgA (IgA1 and IgA2) by the direct immunofluorescence (IF) staining method using specimens in which we identified the deposition of IgA through zero-hour renal transplant biopsies from donors without urinary abnormalities. The samples of the zero-hour biopsies were collected from 46 cases of living renal transplant patients at Nishinomiya Hospital, Hyogo Prefecture, from January 2011 to December 2013. Results In seven of the 46 cases (15%), IgA deposition and C3 in mesangium were confirmed. All seven cases showed IgA1 predominant mesangial deposition on IF. The results of the histological evaluations for all seven cases were Oxford Classification M0.S0.E0.T0. Conclusion This study showed similar patterns of latent mesangial IgA deposition according to IgA subclass and frequency of C3 deposition as IgAN. Latent mesangial IgA deposition may require some, as yet undefined factors, to become clinically apparent as IgAN. PMID:27942230

  17. O-glycosylation of serum IgD in IgA nephropathy.

    PubMed

    Smith, Alice C; de Wolff, Jacob F; Molyneux, Karen; Feehally, John; Barratt, Jonathan

    2006-04-01

    In IgA nephropathy (IgAN), serum IgA1 with abnormal O-glycosylation preferentially deposits in the glomerular mesangium. The control of O-glycosylation is poorly understood. Among Ig isotypes, only IgD, produced early in B cell development, and IgA1, produced by mature B cells, are O-glycosylated. For investigation of the stage of B cell maturation at which the defect seen in IgAN arises, the O-glycosylation of serum IgA1 and IgD was studied in IgAN and controls. Serum was obtained from 20 patients with IgAN and 20 control subjects. The O-glycosylation profiles of native and desialylated IgA1 and IgD were measured in an ELISA-type system using the lectins Helix aspersa and peanut agglutinin, which bind to alternative forms of O-glycan moieties. The lectin-binding patterns of the two immunoglobulins differed in all participants, with that of IgD suggesting that it is more heavily galactosylated than IgA1. Defective O-glycosylation of IgA1, probably taking the form of reduced galactosylation, was confirmed in IgAN in this study. This undergalactosylation was not shared by IgD; in contrast, IgD carried more galactosylated O-glycans in IgAN than controls. The contrasting lectin-binding patterns of IgA1 and IgD shows that Ig O-glycosylation is differentially controlled during B cell maturation. Compared with controls, O-glycosylation in IgAN is incomplete in IgA1 but more complete in IgD. These observations show that abnormal IgA1 O-glycosylation in IgAN is not due to an inherent defect in glycosylation mechanisms but arises only at a later stage in B cell development and may be secondary to aberrant immunoregulation.

  18. Study of IgG subclass profiles of anti-HBs in populations with different HBV infection status.

    PubMed

    Tsai, Tzu-Hsin; Huang, Chien-Fu; Wei, James Cheng-Chung; Ho, Mei-Shang; Wang, Lina; Tsai, Wei-Yu; Lin, Chien-Chou; Xu, Fang-Ling; Yang, Chi-Chiang

    2006-01-01

    To study IgG-specific subclasses of hepatitis B virus (HBV) surface antigen (anti-HBs), in different populations in Taiwan, a comparison was made between 104 chronic carriers (60 male and 44 female) and 439 recovered individuals (247 male and 192 female). Biochemical analyses of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also performed. Among the 104 chronic carriers, 21 patients had abnormal ALT and AST levels (> 25 IU/ml). When comparing the patients with abnormal ALT and AST levels to chronic carriers with normal ALT and AST levels, no statistical difference was observed for anti-HBs levels (p > 0.05). The IgG subclass pattern of the relative anti-HBs IgG subclass titers was IgG1 > IgG3 = IgG4 in both chronic carriers and recovered individuals (p < 0.05). IgG1 is the predominant anti-HBs antibody after HBV infection, in either chronic carriers or in HBV-cured individuals. This finding is partly inconsistent with data reported from other group who suggested in individuals naturally infected, the anti-HBs IgG consists mainly of IgG3 and IgG1. In contrast to that of our previous studies of anti-HBe and anti-HBc, the mean OD values of anti-HBs total IgG, and all IgG subclasses except for IgG2, of either males or females, were significantly higher in recovered individuals than in chronic carriers, while the mean OD values of anti-HBe and anti-HBc were significantly higher in chronic carriers than in recovered individuals (P < 0.05). The IgG subclass profile of anti-HBs in chronic carriers was not changed with liver inflammation and was independent of sex and age, except in individuals with abnormal ALT and AST for whom anti-HBs IgG1 was not significantly higher than IgG3 (p > 0.05), in spite of that whose mean O.D. value is higher.

  19. IgG4-related Orbital Disease and Its Mimics in a Western Population.

    PubMed

    Ferry, Judith A; Klepeis, Veronica; Sohani, Aliyah R; Harris, Nancy Lee; Preffer, Frederic I; Stone, John H; Grove, Arthur; Deshpande, Vikram

    2015-12-01

    Although chronic inflammatory disorders of the ocular adnexa are relatively common, their pathogenesis is in many cases poorly understood. Recent investigation suggests that many cases of sclerosing orbital inflammation are a manifestation of IgG4-related disease; however, most patients reported have been Asian, and it is not clear whether the results of studies from the Far East can be reliably extrapolated to draw conclusions about Western patients. We evaluated 38 cases previously diagnosed as orbital inflammatory pseudotumor or chronic dacryoadenitis to determine whether our cases fulfill the criteria for IgG4-RD (IgG4-related dacryoadenitis when involving the lacrimal gland, and IgG4-related sclerosing orbital inflammation when involving orbital soft tissue). Fifteen patients had IgG4-related dacryoadenitis or orbital inflammation. These patients included 9 men and 6 women, aged 24 to 77 years (median, 64 y). Lesions involved orbital soft tissue (8 cases), lacrimal gland (6 cases), and canthus (1 case). In 1 case, focal in situ follicular neoplasia was seen in a background of IgG4-RD. In another case, a clonal IGH gene rearrangement was detected. Four patients with IgG4-RD had evidence of IgG4-RD in other anatomic sites. Five patients, 1 man and 4 women, aged 26 to 74 years (median 50 y) had orbital lesions (2 involving lacrimal gland, 3 involving soft tissue) suspicious for, but not diagnostic of, IgG4-RD. Of 16 patients with IgG4-RD or probable IgG4-RD with information available regarding the course of their disease, 11 patients experienced recurrent or persistent orbital disease. However, no patient developed lymphoma, and no patient died of complications of IgG4-RD. Eighteen patients had lesions not representing IgG4-RD. They included 6 male and 12 female individuals aged 6 to 77 years (median, 47 y). These patients had a variety of diseases, including granulomatosis with polyangiitis (3 cases), Rosai-Dorfman disease (1 case), nonspecific chronic

  20. JSI-124 inhibits IgE production in an IgE B cell line.

    PubMed

    Cui, Lulu; Bi, Jiacheng; Yan, Dehong; Ye, Xiufeng; Zheng, Mingxing; Yu, Guang; Wan, Xiaochun

    2017-01-29

    IgE is a key effector molecule in atopic diseases; however, the regulation mechanisms of IgE production in IgE B cells remain poorly understood. In the present study, we demonstrate that JSI-124 (cucurbitacin I), a selective STAT3 inhibitor, selectively inhibits production of IgE by a human IgE B cell line, CRL-8033 cells, while does not affect the IgG production by IgG B cell lines. In the aspect of molecular mechanism, we found that Igλ, but not Ighe, gene expression was suppressed by JSI-124. The above effects of JSI-124 were not mediated by affecting cellular proliferation or apoptosis. Furthermore, multiple B cell differentiation-related genes expression was not significantly affected by JSI-124. Taken together, we demonstrate a potential strategy of therapeutically suppressing IgE production without affecting IgG production in atopic patients.

  1. Effect of the mass of immunoglobulin (Ig)G intake and age at first colostrum feeding on serum IgG concentration in Holstein calves.

    PubMed

    Osaka, I; Matsui, Y; Terada, F

    2014-10-01

    Forty-four Holstein calves (19 male and 25 female) were used in this study of the relationships among age at first colostrum feeding, IgG intake, and apparent efficiency of IgG absorption. Time of birth was recorded for each calf and the calves were fed colostrum ad libitum after birth at either 0930 or 1630 h. Blood samples were collected immediately before and 24h after colostrum feeding. Data from calves were then categorized into 4 groups representing time from birth to colostrum feeding: A=fed within 1h (n=5); B=fed from 1 to 6h (n=10); C=fed from 6 to 12 h (n=21); and D=fed from 12 to 18 h (n=8) after birth. Average total intake of colostrum was 3.6 ± 0.1L. Over 80% of the calves consumed ≥3 L of colostrum. Apparent efficiency of IgG absorption declined remarkably 12 h after birth. Mean apparent efficiency of absorption of IgG in group D (15.8 ± 3.0%) was lower than that in groups A (30.5 ± 3.9%) and B (27.4 ± 2.8%). Serum IgG concentration in calves was positively correlated with IgG intake in all groups. The relationship between mass of IgG consumed and calf serum IgG at 24 h was different for each time of colostrum feeding, with only limited differences observed between groups A and B. We concluded that failure of transfer of passive immunity in newborn calves may be avoided if calves consume ≥3 L of colostrum with IgG concentration >40 mg/mL within 6 h after birth. These findings help define the opportunity to minimize failure of transfer of passive immunity to newborn calves under management programs similar to those used on commercial dairy farms.

  2. Potential of astigmatid mites (Acari: Astigmatina) as prey for rearing edaphic predatory mites of the families Laelapidae and Rhodacaridae (Acari: Mesostigmata).

    PubMed

    Barbosa, Marina F C; de Moraes, Gilberto J

    2016-07-01

    Laelapidae and Rhodacaridae are important families of edaphic predatory mites and species of these families have been considered for use in biological control programs of soil pests. Mites of Cohort Astigmatina (Acari: Sarcoptiformes) have been largely used as factitious prey in the mass rearing of various edaphic or plant-inhabiting predatory mites. Stratiolaelaps scimitus (Womersley) (Mesostigmata: Laelapidae) (widely commercialized for the control of fungus gnats and thrips) and Protogamasellopsis zaheri Abo-Shnaf, Castilho and Moraes (Mesostigmata: Rhodacaridae) (not available commercially but promising for the control of thrips and nematodes) are known to be reared on Tyrophagus putrescentiae (Schrank) (Astigmatina: Acaridae), but the possibility to find a perhaps more efficient prey has not been evaluated. The objective of this paper was to evaluate different astigmatid species as prey for these predators. S. scimitus and P. zaheri oviposited on all evaluated astigmatids and the acarid mites T. putrescentiae and Aleuroglyphus ovatus (Tropeau) were the most suitable prey; to confirm the effect of prey on oviposition rates, pregnant females of the predators were kept under starvation conditions and oviposition was negligible or null. Survivorship was always higher than 78 % and was not influenced by prey species or starvation.

  3. Influence of stochastic perturbation on prey-predator systems.

    PubMed

    Rudnicki, Ryszard; Pichór, Katarzyna

    2007-03-01

    We analyse the influence of various stochastic perturbations on prey-predator systems. The prey-predator model is described by stochastic versions of a deterministic Lotka-Volterra system. We study long-time behaviour of both trajectories and distributions of the solutions. We indicate the differences between the deterministic and stochastic models.

  4. Energy and protein content of coyote prey in southeastern Idaho

    SciTech Connect

    MacCracken, J.G.; Hansen, R.M.

    1986-04-30

    Gross energy, digestible energy, crude protein, and digestible crude protein were estimated for two leporids and five rodents that were the primary prey of coyotes (Canis latrans) in southeastern Idaho. Digestible protein estimates differed (38%-54%) more than digestible energy (3.5-4.4 kcal), in the prey examined. 15 references, 1 table.

  5. Unusual predator-prey dynamics under reciprocal phenotypic plasticity.

    PubMed

    Mougi, Akihiko

    2012-07-21

    Recent theories and experiments have shown that plasticity, such as an inducible defense or an inducible offense in predator-prey interactions, strongly influences the stability of the population dynamics. However, such plastic adaptation has not been expected to cause unusual dynamics such as antiphase cycles, which occur in experimental predator-prey systems with evolutionary adaptation in the defensive trait of prey. Here I show that antiphase cycles and cryptic cycles (a large population fluctuation in one species with almost no change in the population of the other species) can occur in a predator-prey system when both member species can change their phenotypes through adaptive plasticity (inducible defenses and offenses). I consider a familiar type of predator-prey system in which both species can change their morphology or behavior through phenotypic plasticity. The plasticity, that is, the ability to change between distinct phenotypes, is assumed to occur so as to maximize their fitness. I examined how the reciprocal adaptive plasticity influences the population dynamics. The results show that unusual dynamics such as antiphase population cycles and cryptic cycles can occur when both species show inducible plasticity. The unusual dynamics are particularly likely to occur when the carrying capacity of the prey is small (the density dependence of the prey's growth is strong). The unusual predator-prey dynamics may be induced by phenotypic plasticity as long as the phenotypic change occurs to maximize fitness.

  6. Red fox prey demands and implications to prairie duck production

    USGS Publications Warehouse

    Sargeant, A.B.

    1978-01-01

    Experiments were conducted during spring and summer with 33 red foxes (Vulpes vulpes) to determine prey demands, feeding characteristics, and growth rates using natural foods. Pups began eating prey the 4th week after birth. Then, prey consumption averaged 1.38 and 1.90 kg/pup/week for weeks 5-8 and 9-12 of the denning season respectively, and 2.54 kg/pup/week for the postdenning period. Feeding by adults averaged 2.25 kg/adult/week. Free water was not needed by either pups or adults. About 90 percent of the prey offered to pups on simulated natural diets was consumed, remains varied with prey availability and prey type. Prey biomass required by a typical fox family was estimated at 18.5 kg/km2 for the 12-week denning season and 2.4 kg/km2/week for the postdenning period. Because of the large prey demands, ducks could represent a small part of the foxes' diet and yet be of consequence to the productivity of particular species. An example is provided for the mallard (Anas platyrhynchos).

  7. Aggregative response in bats: prey abundance versus habitat.

    PubMed

    Müller, Jörg; Mehr, Milenka; Bässler, Claus; Fenton, M Brock; Hothorn, Torsten; Pretzsch, Hans; Klemmt, Hans-Joachim; Brandl, Roland

    2012-07-01

    In habitats where prey is either rare or difficult to predict spatiotemporally, such as open habitats, predators must be adapted to react effectively to variations in prey abundance. Open-habitat foraging bats have a wing morphology adapted for covering long distances, possibly use information transfer to locate patches of high prey abundance, and would therefore be expected to show an aggregative response at these patches. Here, we examined the effects of prey abundance on foraging activities of open-habitat foragers in comparison to that of edge-habitat foragers and closed-habitat foragers. Bat activity was estimated by counting foraging calls recorded with bat call recorders (38,371 calls). Prey abundance was estimated concurrently at each site using light and pitfall traps. The habitat was characterized by terrestrial laser scanning. Prey abundance increased with vegetation density. As expected, recordings of open-habitat foragers clearly decreased with increasing vegetation density. The foraging activity of edge- and closed-habitat foragers was not significantly affected by the vegetation density, i.e., these guilds were able to forage from open habitats to habitats with dense vegetation. Only open-habitat foragers displayed a significant and proportional aggregative response to increasing prey abundance. Our results suggest that adaptations for effective and low-cost foraging constrains habitat use and excludes the guild of open-habitat foragers from foraging in habitats with high prey abundance, such as dense forest stands.

  8. Prey behavior, age-dependent vulnerability, and predation rates.

    PubMed

    Lingle, Susan; Feldman, Alex; Boyce, Mark S; Wilson, W Finbarr

    2008-11-01

    Variation in the temporal pattern of vulnerability can provide important insights into predator-prey relationships and the evolution of antipredator behavior. We illustrate these points with a system that has coyotes (Canis latrans) as a predator and two species of congeneric deer (Odocoileus spp.) as prey. The deer employ different antipredator tactics (aggressive defense vs. flight) that result in contrasting patterns of age-dependent vulnerability in their probability of being captured when encountered by coyotes. We use long-term survival data and a simple mathematical model to show that (1) species differences in age-dependent vulnerability are reflected in seasonal predation rates and (2) seasonal variation in prey vulnerability and predator hunt activity, which can be associated with the availability of alternative prey, interact to shape seasonal and annual predation rates for each prey species. Shifting hunt activity from summer to winter, or vice versa, alleviated annual mortality on one species and focused it on the other. Our results indicate that seasonal variation in prey vulnerability and hunt activity interact to influence the impact that a predator has on any particular type of prey. Furthermore, these results indicate that seasonal variation in predation pressure is an important selection pressure shaping prey defenses.

  9. IGS Data Center Working Group Report

    NASA Technical Reports Server (NTRS)

    Noll, Carey E.

    2004-01-01

    At its 18th meeting held December 09, 2001 in San Francisco, the IGS Governing Board recommended the formation of a working group to focus on data center issues. This working group will tackle many of the problems facing the IGS data centers as well as develop new ideas to aid users both internal and external to the IGS. The direction of the IGS has changed since its start in 1992 and many new working groups, projects, data sets, and products have been created and incorporated into the service since that time. Therefore, this may be an appropriate time to revisit the requirements of data centers within the IGS.

  10. Piscivore-prey fish interactions: mechanisms behind diurnal patterns in prey selectivity in brown and clear water.

    PubMed

    Ranåker, Lynn; Persson, Jens; Jönsson, Mikael; Nilsson, P Anders; Brönmark, Christer

    2014-01-01

    Environmental change may affect predator-prey interactions in lakes through deterioration of visual conditions affecting foraging success of visually oriented predators. Environmental change in lakes includes an increase in humic matter causing browner water and reduced visibility, affecting the behavioural performance of both piscivores and prey. We studied diurnal patterns of prey selection in piscivorous pikeperch (Sander lucioperca) in both field and laboratory investigations. In the field we estimated prey selectivity and prey availability during day and night in a clear and a brown water lake. Further, prey selectivity during day and night conditions was studied in the laboratory where we manipulated optical conditions (humic matter content) of the water. Here, we also studied the behaviours of piscivores and prey, focusing on foraging-cycle stages such as number of interests and attacks by the pikeperch as well as the escape distance of the prey fish species. Analyses of gut contents from the field study showed that pikeperch selected perch (Perca fluviatilis) over roach (Rutilus rutilus) prey in both lakes during the day, but changed selectivity towards roach in both lakes at night. These results were corroborated in the selectivity experiments along a brown-water gradient in day and night light conditions. However, a change in selectivity from perch to roach was observed when the optical condition was heavily degraded, from either brown-stained water or light intensity. At longer visual ranges, roach initiated escape at distances greater than pikeperch attack distances, whereas perch stayed inactive making pikeperch approach and attack at the closest range possible. Roach anti-predatory behaviour decreased in deteriorated visual conditions, altering selectivity patterns. Our results highlight the importance of investigating both predator and prey responses to visibility conditions in order to understand the effects of degrading optical conditions on

  11. Behavioral response races, predator-prey shell games, ecology of fear, and patch use of pumas and their ungulate prey.

    PubMed

    Laundré, John W

    2010-10-01

    The predator-prey shell game predicts random movement of prey across the landscape, whereas the behavioral response race and landscape of fear models predict that there should be a negative relationship between the spatial distribution of a predator and its behaviorally active prey. Additionally, prey have imperfect information on the whereabouts of their predator, which the predator should incorporate in its patch use strategy. I used a one-predator-one-prey system, puma (Puma concolor)-mule deer (Odocoileus hemionus) to test the following predictions regarding predator-prey distribution and patch use by the predator. (1) Pumas will spend more time in high prey risk/low prey use habitat types, while deer will spend their time in low-risk habitats. Pumas should (2) select large forage patches more often, (3) remain in large patches longer, and (4) revisit individual large patches more often than individual smaller ones. I tested these predictions with an extensive telemetry data set collected over 16 years in a study area of patchy forested habitat. When active, pumas spent significantly less time in open areas of low intrinsic predation risk than did deer. Pumas used large patches more than expected, revisited individual large patches significantly more often than smaller ones, and stayed significantly longer in larger patches than in smaller ones. The results supported the prediction of a negative relationship in the spatial distribution of a predator and its prey and indicated that the predator is incorporating the prey's imperfect information about its presence. These results indicate a behavioral complexity on the landscape scale that can have far-reaching impacts on predator-prey interactions.

  12. Biological Control Outcomes Using the Generalist Aphid Predator Aphidoletes aphidimyza under Multi-Prey Conditions.

    PubMed

    Jandricic, Sarah E; Wraight, Stephen P; Gillespie, Dave R; Sanderson, John P

    2016-12-14

    The aphidophagous midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae) is used in biological control programs against aphids in many crops. Short-term trials with this natural enemy demonstrated that that females prefer to oviposit among aphids colonizing the new growth of plants, leading to differential attack rates for aphid species that differ in their within-plant distributions. Thus, we hypothesized that biological control efficacy could be compromised when more than one aphid species is present. We further hypothesized that control outcomes may be different at different crop stages if aphid species shift their preferred feeding locations. Here, we used greenhouse trials to determine biological control outcomes using A. aphidimyza under multi-prey conditions and at different crop stages. At all plant stages, aphid species had a significant effect on the number of predator eggs laid. More eggs were found on M. persicae versus A. solani-infested plants, since M. persicae consistently colonized plant meristems across plant growth stages. This translated to higher numbers of predatory larvae on M. periscae-infested plants in two out of our three experiments, and more consistent control of this pest (78%-95% control across all stages of plant growth). In contrast, control of A. solani was inconsistent in the presence of M. persicae, with 36%-80% control achieved. An additional experiment demonstrated control of A. solani by A. aphidimyza was significantly greater in the absence of M. persicae than in its presence. Our study illustrates that suitability of a natural enemy for pest control may change over a crop cycle as the position of prey on the plant changes, and that prey preference based on within-plant prey location can negatively influence biological control programs in systems with pest complexes. Careful monitoring of the less-preferred pest and its relative position on the plant is suggested.

  13. Biological Control Outcomes Using the Generalist Aphid Predator Aphidoletes aphidimyza under Multi-Prey Conditions

    PubMed Central

    Jandricic, Sarah E.; Wraight, Stephen P.; Gillespie, Dave R.; Sanderson, John P.

    2016-01-01

    The aphidophagous midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae) is used in biological control programs against aphids in many crops. Short-term trials with this natural enemy demonstrated that that females prefer to oviposit among aphids colonizing the new growth of plants, leading to differential attack rates for aphid species that differ in their within-plant distributions. Thus, we hypothesized that biological control efficacy could be compromised when more than one aphid species is present. We further hypothesized that control outcomes may be different at different crop stages if aphid species shift their preferred feeding locations. Here, we used greenhouse trials to determine biological control outcomes using A. aphidimyza under multi-prey conditions and at different crop stages. At all plant stages, aphid species had a significant effect on the number of predator eggs laid. More eggs were found on M. persicae versus A. solani-infested plants, since M. persicae consistently colonized plant meristems across plant growth stages. This translated to higher numbers of predatory larvae on M. periscae-infested plants in two out of our three experiments, and more consistent control of this pest (78%–95% control across all stages of plant growth). In contrast, control of A. solani was inconsistent in the presence of M. persicae, with 36%–80% control achieved. An additional experiment demonstrated control of A. solani by A. aphidimyza was significantly greater in the absence of M. persicae than in its presence. Our study illustrates that suitability of a natural enemy for pest control may change over a crop cycle as the position of prey on the plant changes, and that prey preference based on within-plant prey location can negatively influence biological control programs in systems with pest complexes. Careful monitoring of the less-preferred pest and its relative position on the plant is suggested. PMID:27983620

  14. IgM and IgD concentrations in the serum and secretions of children with selective IgA deficiency.

    PubMed Central

    Plebani, A; Mira, E; Mevio, E; Monafo, V; Notarangelo, L D; Avanzini, A; Ugazio, A G

    1983-01-01

    Serum IgG and serum and secretory IgM, IgA and IgD levels were determined in 14 children with selective IgA deficiency and in 12 age and sex matched healthy controls. IgD was determined using a highly sensitive ELISA technique. In the healthy controls serum IgG, IgA and IgM were all in the age normal range, and serum IgA was significantly higher than secretory IgA with IgA in nasal secretions being significantly higher than in saliva. In the IgA deficient children serum IgG and IgM and secretory IgM were present in higher concentrations than in the controls but the difference was statistically significant only for serum IgG and salivary IgM. IgD was detectable in the serum and secretions of all patients and all but one control subject. Like IgM, serum IgD levels were significantly higher than secretory IgD levels and IgD was present in greater concentrations in nasal secretions than in saliva both in the patients and the controls, with no difference between the two groups. Thus, the data of this study show that while serum and secretory IgM levels are elevated in children with selective IgA deficiency, serum and secretory IgD are present in normal concentrations, supporting the hypothesis of a compensatory increase in IgM but not in IgD in such patients. PMID:6616961

  15. Supplementary Feeding, Plumage Documentation and Early Season Prey of Peregrine Falcons at the New Mexico Alpha Eyrie

    SciTech Connect

    Ponton, David A.

    2015-03-20

    A review of what is known about avian physiology and the biological effects of DDE suggests that some benefit to peregrine falcon egg condition could be attained by artificially feeding DDE free prey to the female from the time of her arrival on the nesting grounds until completion of egg laying; the magnitude of potential benefit is unknown. Sporadic efforts in the past demonstrated the need for precision methods of prey delivery. Two methods were developed and tried; providing dead prey items by dropping them in a day perch, and delivery of live prey by remotely controlled release from compartments positioned at the top of the cliff occupied by the falcons. Maintaining quail in the day perch for 21 days resulted in at least one and probably two meals for the female peregrine. Of 16 live birds released (mostly pigeons) 13 were pursued and three caught. Blinding the pigeons with tape proved to be necessary to enable capture. Also, some reluctance of the male peregrine to attack pigeons was observed, and problems with equipment, visibility, and the proximity of the falcons to the release box were encountered. Manpower was the most significant resource requirement. Baiting of great-horned owls, possibly leading to owl attack on the falcons, is judged to be the largest detrimental effect of supplemental feeding. It is recommended that supplemental feeding be reserved for falcons or eyries where complete reproductive failure is expected. Plumage documentation photography was successfully conducted by a remotely controlled camera as an aid to identification of individual falcons. American robin, red-winged blackbird, starling, white-throated swift, bluebird, and mourning dove were among natural prey consumed by the peregrines before completion of egg laying. All activities in close proximity to the cliff were conducted at night to preclude direct disturbance of the falcons.

  16. Polymeric IgA rheumatoid factor in idiopathic IgA mesangial nephropathy (Berger's disease).

    PubMed

    Sinico, R A; Fornasieri, A; Oreni, N; Benuzzi, S; D'Amico, G

    1986-07-15

    A specific and sensitive enzyme-linked immunosorbent assay (ELISA) was used to detect IgA rheumatoid factor (RF) in sera from 88 patients with IgA nephropathy (IgA GN), a disease characterized by abnormalities of IgA production. Significantly higher levels of IgA antiglobulins were demonstrated in IgA GN patients than in normal healthy controls and patients with other forms of chronic primary glomerulonephritis (mean +/- SEM 28.4 +/- 6.6 vs 6.0 +/- 0.4 and 8.3 +/- 1.2 micrograms/ml respectively; p less than 0.002). Interestingly, in contrast to rheumatoid arthritis, IgA RF activity was not associated with IgM antiglobulins. Analysis of sera fractionated by gel chromatography at acid pH revealed that anti-IgG activity resided predominantly in the polymeric fractions of IgA as confirmed by the ability to bind "free" secretory component. Several findings in patients with IgA GN suggest that the IgA deposited in the glomeruli is polymeric, and levels of circulating macromolecular IgA are increased. Our findings confirm a general perturbation of IgA metabolism in this disease. Although the polymeric nature of the IgA RF is suggestive of a mucosal origin, additional evidence is needed to confirm this hypothesis.

  17. Unusual myelomas: a review of IgD and IgE variants.

    PubMed

    Pandey, Shivlal; Kyle, Robert A

    2013-08-01

    Immunoglobulin D multiple myeloma (IgD MM) accounts for almost 2% of all myeloma cases. It is associated with an increased frequency of undetectable or small monoclonal (M)-protein levels on electrophoresis; osteolytic lesions; extramedullary involvement; amyloidosis; a lambda (lambda) light chain predilection; renal failure; hypercalcemia; and, often, advanced disease at diagnosis. Immunoglobulin E (IgE) MM is rare, with fewer than 50 cases reported in the literature. IgE MM presents with features similar to those of IgD MM, along with a higher incidence of plasma cell leukemia. The hallmark of IgE MM is t(11;14) (q13;q32). IgD and IgE levels are generally very low and hence may escape detection; thus, it is important that, when myeloma is suspected, patients be screened for the presence of IgD and IgE if they have an apparently free monoclonal immunoglobulin light chain in the serum. Although survival of patients with IgD MM or IgE MM is shorter in comparison to those with immunoglobulin G (IgG) MM or immunoglobulin A (IgA) MM, the outcome for patients with IgD and IgE subtypes is improving with the use of novel agents and autologous transplantation.

  18. Bioeconomic harvesting of a prey-predator fishery.

    PubMed

    Das, Tapasi; Mukherjee, R N; Chaudhuri, K S

    2009-09-01

    This paper deals with the problem of non-selective harvesting of a prey-predator system by using a reasonable catch-rate function instead of usual catch-per-unit-efforthypothesis. Here both the prey and the predator species obey the law of logistic growth. We have taken the predator functional response to prey density in such a form that each predator's functional response to the prey density approaches a constant as the prey population increases. Boundedness of the exploited system is examined. The existence of its steady states and their stability (local and global) are studied using Eigenvalue analysis. The existence of bionomic equilibria has been illustrated using a numerical example. The problem of determining the optimal harvesting policy is then solved by using Pontryagin's maximum principle.

  19. Unique coevolutionary dynamics in a predator-prey system.

    PubMed

    Mougi, Akihiko; Iwasa, Yoh

    2011-05-21

    In this paper, we study the predator-prey coevolutionary dynamics when a prey's defense and a predator's offense change in an adaptive manner, either by genetic evolution or phenotypic plasticity, or by behavioral choice. Results are: (1) The coevolutionary dynamics are more likely to be stable if the predator adapts faster than the prey. (2) The prey population size can be nearly constant but the predator population can show very large amplitude fluctuations. (3) Both populations may oscillate in antiphase. All of these are not observed when the handling time is short and the prey's density dependence is weak. (4) The population dynamics and the trait dynamics show resonance: the amplitude of the population fluctuation is the largest when the speed of adaptation is intermediate. These results may explain experimental studies with microorganisms.

  20. Inherited forms of IgA nephropathy.

    PubMed

    Scolari, Francesco

    2003-01-01

    Simplex and multiplex families with IgA nephropathy (IgAN) have been reported from several ethnic backgrounds, providing the strongest evidence of a role for genetic factors in pathogenesis of IgAN. From a phenotypic point of view, familial and sporadic IgAN cannot be differentiated, and the main clinical and histological features are similar. Traditionally, the case-control study design was employed to identify associations between particular candidate genes, for example, HLA antigens the uteroglobin gene and IgAN, giving conflicting results. Recently, a different approach, using linkage analysis, was undertaken by geneticists at Yale University. A 10-cM genome-wide screen was performed in 30 multiplex IgAN pedigrees, and one locus was mapped (IGAN-1) on chromosome 6q22-23. Future study will be focused on the identification of the gene underlying IGAN-1. This will enable us to understand the molecular pathogenetic basis of IgAN.

  1. Heuristic Rules Underlying Dragonfly Prey Selection and Interception.

    PubMed

    Lin, Huai-Ti; Leonardo, Anthony

    2017-03-28

    Animals use rules to initiate behaviors. Such rules are often described as triggers that determine when behavior begins. However, although less explored, these selection rules are also an opportunity to establish sensorimotor constraints that influence how the behavior ends. These constraints may be particularly significant in influencing success in prey capture. Here we explore this in dragonfly prey interception. We found that in the moments leading up to takeoff, perched dragonflies employ a series of sensorimotor rules that determine the time of takeoff and increase the probability of successful capture. First, the dragonfly makes a head saccade followed by smooth pursuit movements to orient its direction-of-gaze at potential prey. Second, the dragonfly assesses whether the prey's angular size and speed co-vary within a privileged range. Finally, the dragonfly times the moment of its takeoff to a prediction of when the prey will cross the zenith. Each of these processes serves a purpose. The angular size-speed criteria biases interception flights to catchable prey, while the head movements and the predictive takeoff ensure flights begin with the prey visually fixated and directly overhead-the key parameters that underlie interception steering. Prey that do not elicit takeoff generally fail at least one of the criterion, and the loss of prey fixation or overhead positioning during flight is strongly correlated with terminated flights. Thus from an abundance of potential targets, the dragonfly selects a stereotyped set of takeoff conditions based on the prey and body states most likely to end in successful capture.

  2. Modelling the fear effect in predator-prey interactions.

    PubMed

    Wang, Xiaoying; Zanette, Liana; Zou, Xingfu

    2016-11-01

    A recent field manipulation on a terrestrial vertebrate showed that the fear of predators alone altered anti-predator defences to such an extent that it greatly reduced the reproduction of prey. Because fear can evidently affect the populations of terrestrial vertebrates, we proposed a predator-prey model incorporating the cost of fear into prey reproduction. Our mathematical analyses show that high levels of fear (or equivalently strong anti-predator responses) can stabilize the predator-prey system by excluding the existence of periodic solutions. However, relatively low levels of fear can induce multiple limit cycles via subcritical Hopf bifurcations, leading to a bi-stability phenomenon. Compared to classic predator-prey models which ignore the cost of fear where Hopf bifurcations are typically supercritical, Hopf bifurcations in our model can be both supercritical and subcritical by choosing different sets of parameters. We conducted numerical simulations to explore the relationships between fear effects and other biologically related parameters (e.g. birth/death rate of adult prey), which further demonstrate the impact that fear can have in predator-prey interactions. For example, we found that under the conditions of a Hopf bifurcation, an increase in the level of fear may alter the direction of Hopf bifurcation from supercritical to subcritical when the birth rate of prey increases accordingly. Our simulations also show that the prey is less sensitive in perceiving predation risk with increasing birth rate of prey or increasing death rate of predators, but demonstrate that animals will mount stronger anti-predator defences as the attack rate of predators increases.

  3. Detection of IgE, IgG, IgA and IgM antibodies against raw and processed food antigens

    PubMed Central

    Vojdani, Aristo

    2009-01-01

    Background Despite the first documented case of food allergy to cooked food in 1921 by Prausnitz and Kustner, all commercial food antigens are prepared from raw food. Furthermore, all IgE and IgG antibodies against dietary proteins offered by many clinical laboratories are measured against raw food antigens. Methods We developed an enzyme-linked immunosorbent assay for the measurement of IgE, IgG, IgA and IgM antibodies against raw and processed food antigens. Sera with low or high reactivity to modified food antigens were subjected to myelin basic protein, oxidized low density lipoprotein, and advanced glycation end products (AGE) such as AGE-human serum albumin and AGE-hemoglobin. Results Compared to raw food antigens, IgE antibodies showed a 3–8-fold increase against processed food antigens in 31% of the patients. Similarly, IgG, IgA and IgM antibodies against modified food antigens overall were found at much higher levels than antibody reactions against raw food antigens. Almost every tested serum with high levels of antibodies against modified food antigens showed very high levels of antibodies against myelin basic protein, oxidized low density lipoprotein, AGE-human serum albumin and AGE-hemoglobin. Conclusion We conclude that the determination of food allergy, intolerance and sensitivity would be improved by testing IgE, IgG, IgA and IgM antibodies against both raw and processed food antigens. Antibodies against modified food antigens, by reacting with AGEs and tissue proteins, may cause perturbation in degenerative and autoimmune diseases such as diabetes, atherosclerosis, inflammation, autoimmunity, neurodegeneration and neuroautoimmunity. PMID:19435515

  4. Prey to predator size ratio influences foraging efficiency of larval Aeshna juncea dragonflies.

    PubMed

    Hirvonen, Heikki; Ranta, Esa

    1996-05-01

    We investigated foraging behaviour of larval dragonflies Aeshna juncea in order to examine the significance of prey density and body size in predator-prey dynamics. A. juncea were offered separately three size-classes of Daphnia magna at low and high densities. The data were collected with direct observations of the foraging individuals. We found that large A. juncea larvae could better enhance their intake of prey biomass as prey size and prey density increased than their smaller conspecifics. However, increasing feeding efficiency of both larval instars was constrained by declining attack success and search rate with increasing prey size and density. With small D. magna, in contrast to large A. juncea, small A. juncea increased their searching efficiency as prey density increased keeping D. magna mortality rate at a constant level. In a predator-prey relationship this indicates stabilizing potential and feeding thresholds set by both prey density and prey-predator size ratio. Attack success dropped with prey size and density, but did not change in the course of the foraging bout. For both A. juncea sizes prey handling times increased as more medium and large prey were eaten. The slope of the increase became steeper with increasing prey-predator size ratio. These observations indicate that components of the predator-prey relationship vary with prey density, contrary to the basic assumptions of functional response equations. Moreover, the results suggest that the effects of prey density change during the ontogeny of predators and prey.

  5. Female Condom

    MedlinePlus

    ... Nov. 13, 2014. Hatcher RA, et al. Contraceptive Technology. 20th ed. New York, N.Y.: Ardent Media; 2011:391. FC2 female condom. U.S. Food and Drug Administration. http://www.accessdata.fda.gov/ ...

  6. Stability and Hopf bifurcation for a prey-predator model with prey-stage structure and diffusion.

    PubMed

    Wang, Mingxin

    2008-04-01

    In this paper, we first propose a prey-predator model with prey-stage structure and diffusion. Then we discuss the following three problems: (1) stability of non-negative constant steady states for the reduced ODE system and the corresponding reaction diffusion system with homogeneous Neumann boundary conditions; (2) Hopf bifurcation for the ODE system; (3) Hopf bifurcation created by diffusion.

  7. Evaluation of rubella virus immunoglobulin G (IgG) and IgM assays with the new Vidia instrument.

    PubMed

    Medici, Maria Cristina; Martinelli, Monica; Albonetti, Valeria; Chezzi, Carlo; Dettori, Giuseppe

    2008-05-01

    For rubella virus immunoglobulin G (IgG) and IgM detection, Vidia assays were compared to Vidas, AxSYM, and Liaison assays with 419 serum samples. Only Vidia produced a sensitivity of 100% for IgG and IgM. Vidia specificities were 98.4% for IgG and 99.8% for IgM, versus Vidas specificities of 100 and 99.3%. Vidia IgG and IgM assays performed equally well.

  8. Modelling the Effects of Prey Size and Distribution on Prey Capture Rates of Two Sympatric Marine Predators

    PubMed Central

    Thaxter, Chris B.; Daunt, Francis; Grémillet, David; Harris, Mike P.; Benvenuti, Silvano; Watanuki, Yutaka; Hamer, Keith C.; Wanless, Sarah

    2013-01-01

    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5±0.8 items per dive (0.8±0.4 and 1.1±0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7±2.4 items per dive (4.9±3.1 and 7.3±4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in predicting likely

  9. Modelling the effects of prey size and distribution on prey capture rates of two sympatric marine predators.

    PubMed

    Thaxter, Chris B; Daunt, Francis; Grémillet, David; Harris, Mike P; Benvenuti, Silvano; Watanuki, Yutaka; Hamer, Keith C; Wanless, Sarah

    2013-01-01

    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5 ± 0.8 items per dive (0.8 ± 0.4 and 1.1 ± 0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7 ± 2.4 items per dive (4.9 ± 3.1 and 7.3 ± 4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in

  10. Degraded environments alter prey risk assessment.

    PubMed

    Lönnstedt, Oona M; McCormick, Mark I; Chivers, Douglas P

    2012-01-01

    Elevated water temperatures, a decrease in ocean pH, and an increasing prevalence of severe storms have lead to bleaching and death of the hard corals that underpin coral reef ecosystems. As coral cover declines, fish diversity and abundance declines. How degradation of coral reefs affects behavior of reef inhabitants is unknown. Here, we demonstrate that risk assessment behaviors of prey are severely affected by coral degradation. Juvenile damselfish were exposed to visual and olfactory indicators of predation risk in healthy live, thermally bleached, and dead coral in a series of laboratory and field experiments. While fish still responded to visual cues in all habitats, they did not respond to olfactory indicators of risk in dead coral habitats, likely as a result of alteration or degradation of chemical cues. These cues are critical for learning and avoiding predators, and a failure to respond can have dramatic repercussions for survival and recruitment.

  11. Competing conservation objectives for predators and prey: estimating killer whale prey requirements for Chinook salmon.

    PubMed

    Williams, Rob; Krkošek, Martin; Ashe, Erin; Branch, Trevor A; Clark, Steve; Hammond, Philip S; Hoyt, Erich; Noren, Dawn P; Rosen, David; Winship, Arliss

    2011-01-01

    Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada-US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict

  12. Competing Conservation Objectives for Predators and Prey: Estimating Killer Whale Prey Requirements for Chinook Salmon

    PubMed Central

    Williams, Rob; Krkošek, Martin; Ashe, Erin; Branch, Trevor A.; Clark, Steve; Hammond, Philip S.; Hoyt, Erich; Noren, Dawn P.; Rosen, David; Winship, Arliss

    2011-01-01

    Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada–US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict

  13. Prey risk allocation in a grazing ecosystem.

    PubMed

    Gude, Justin A; Garrott, Robert A; Borkowski, John J; King, Fred

    2006-02-01

    Understanding the behaviorally mediated indirect effects of predators in ecosystems requires knowledge of predator-prey behavioral interactions. In predator-ungulate-plant systems, empirical research quantifying how predators affect ungulate group sizes and distribution, in the context of other influential variables, is particularly needed. The risk allocation hypothesis proposes that prey behavioral responses to predation risk depend on background frequencies of exposure to risk, and it can be used to make predictions about predator-ungulate-plant interactions. We determined non-predation variables that affect elk (Cervus elaphus) group sizes and distribution on a winter range in the Greater Yellowstone Ecosystem (GYE) using logistic and log-linear regression on surveys of 513 1-km2 areas conducted over two years. Employing model selection techniques, we evaluated risk allocation and other a priori hypotheses of elk group size and distributional responses to wolf (Canis lupus) predation risk while accounting for influential non-wolf-predation variables. We found little evidence that wolves affect elk group sizes, which were strongly influenced by habitat type and hunting by humans. Following predictions from the risk allocation hypothesis, wolves likely created a more dynamic elk distribution in areas that they frequently hunted, as elk tended to move following wolf encounters in those areas. This response should dilute elk foraging pressure on plant communities in areas where they are frequently hunted by wolves. We predict that this should decrease the spatial heterogeneity of elk impacts on grasslands in areas that wolves frequently hunt. We also predict that this should decrease browsing pressure on heavily browsed woody plant stands in certain areas, which is supported by recent research in the GYE.

  14. Wave propagation in predator-prey systems

    NASA Astrophysics Data System (ADS)

    Fu, Sheng-Chen; Tsai, Je-Chiang

    2015-12-01

    In this paper, we study a class of predator-prey systems of reaction-diffusion type. Specifically, we are interested in the dynamical behaviour for the solution with the initial distribution where the prey species is at the level of the carrying capacity, and the density of the predator species has compact support, or exponentially small tails near x=+/- ∞ . Numerical evidence suggests that this will lead to the formation of a pair of diverging waves propagating outwards from the initial zone. Motivated by this phenomenon, we establish the existence of a family of travelling waves with the minimum speed. Unlike the previous studies, we do not use the shooting argument to show this. Instead, we apply an iteration process based on Berestycki et al 2005 (Math Comput. Modelling 50 1385-93) to construct a set of super/sub-solutions. Since the underlying system does not enjoy the comparison principle, such a set of super/sub-solutions is not based on travelling waves, and in fact the super/sub-solutions depend on each other. With the aid of the set of super/sub-solutions, we can construct the solution of the truncated problem on the finite interval, which, via the limiting argument, can in turn generate the wave solution. There are several advantages to this approach. First, it can remove the technical assumptions on the diffusivities of the species in the existing literature. Second, this approach is of PDE type, and hence it can shed some light on the spreading phenomenon indicated by numerical simulation. In fact, we can compute the spreading speed of the predator species for a class of biologically acceptable initial distributions. Third, this approach might be applied to the study of waves in non-cooperative systems (i.e. a system without a comparison principle).

  15. Genetic linkage of IgA deficiency to the major histocompatibility complex: evidence for allele segregation distortion, parent-of-origin penetrance differences, and the role of anti-IgA antibodies in disease predisposition.

    PubMed Central

    Vorechovský, I; Webster, A D; Plebani, A; Hammarström, L

    1999-01-01

    Immunoglobulin A (IgA) deficiency (IgAD) is characterized by a defect of terminal lymphocyte differentiation, leading to a lack of IgA in serum and mucosal secretions. Familial clustering, variable population prevalence in different ethnic groups, and a predominant inheritance pattern suggest a strong genetic predisposition to IgAD. The genetic susceptibility to IgAD is shared with a less prevalent, but more profound, defect called "common variable immunodeficiency" (CVID). Here we show an increased allele sharing at 6p21 in affected members of 83 multiplex IgAD/CVID pedigrees and demonstrate, using transmission/diseqilibrium tests, family-based associations indicating the presence of a predisposing locus, designated "IGAD1," in the proximal part of the major histocompatibility complex (MHC). The recurrence risk of IgAD was found to depend on the sex of parents transmitting the defect: affected mothers were more likely to produce offspring with IgAD than were affected fathers. Carrier mothers but not carrier fathers transmitted IGAD1 alleles more frequently to the affected offspring than would be expected under random segregation. The differential parent-of-origin penetrance is proposed to reflect a maternal effect mediated by the production of anti-IgA antibodies tentatively linked to IGAD1. This is supported by higher frequency of anti-IgA-positive females transmitting the disorder to children, in comparison with female IgAD nontransmitters, and by linkage data in the former group. Such pathogenic mechanisms may be shared by other MHC-linked complex traits associated with the production of specific autoantibodies, parental effects, and a particular MHC haplotype. PMID:10090895

  16. IgG4-related disease mimicking chalazion in the upper eyelid with skin manifestations on the trunk.

    PubMed

    Leivo, Tiina; Koskenmies, Sari; Uusitalo, Marita; Tynninen, Olli

    2015-08-01

    IgG4-related disease is a recently defined inflammatory process characterized by IgG4-bearing plasma cells in the involved tissues. The most common sites of involvement are the pancreas, hepatobiliary tract, salivary glands, lymph nodes, retroperitoneum and orbit, especially the lacrimal glands. Other ocular or ocular adnexal sites are rare. To our knowledge, there is one reported case of a conjunctival involvement. We describe a patient, who had an IgG4-RD mimicking chalazion in the upper eyelid, confined to the tarsus, with multiple skin lesions on the trunk. This is a case report of a 55-year-old female. A 55-year-old female presented with an upper eyelid lesion, which was clinically diagnosed as chalazion and drained three times. Histopathological diagnoses were chalazion and inflammation with mixed cells, respectively. Additionally, the patient had had skin nodules on the trunk for several years. Finally, after a third recurrence, the tarsal eyelid lesion was completely excised. The tarsal pathology specimen showed 85 IgG4 positive plasma cells per HPF and the IgG4/IgG ratio was 0.64, suggesting a probable IgG4-related disease. The re-examined skin lesions resembled histologically the eyelid lesion. It is essential to be aware of IgG4-related disease, including in recurrent chalazia.

  17. Analysis of Prey-Predator Three Species Fishery Model with Harvesting Including Prey Refuge and Migration

    NASA Astrophysics Data System (ADS)

    Roy, Sankar Kumar; Roy, Banani

    In this article, a prey-predator system with Holling type II functional response for the predator population including prey refuge region has been analyzed. Also a harvesting effort has been considered for the predator population. The density-dependent mortality rate for the prey, predator and super predator has been considered. The equilibria of the proposed system have been determined. Local and global stabilities for the system have been discussed. We have used the analytic approach to derive the global asymptotic stabilities of the system. The maximal predator per capita consumption rate has been considered as a bifurcation parameter to evaluate Hopf bifurcation in the neighborhood of interior equilibrium point. Also, we have used fishing effort to harvest predator population of the system as a control to develop a dynamic framework to investigate the optimal utilization of the resource, sustainability properties of the stock and the resource rent is earned from the resource. Finally, we have presented some numerical simulations to verify the analytic results and the system has been analyzed through graphical illustrations.

  18. The packaging problem: bivalve prey selection and prey entry techniques of the octopus Enteroctopus dofleini.

    PubMed

    Anderson, Roland C; Mather, Jennifer A

    2007-08-01

    Many predators face a complex step of prey preparation before consumption. Octopuses faced with bivalve prey use several techniques to penetrate the shells to gain access to the meat inside. When given prey of mussels Mytilus trossulus, Manila clams Venerupis philippinarum, and littleneck clams Protothaca staminea, Enteroctopus dofleini solved the problem differently. They pulled apart V. philippinarum and M. trossulus, which had the thinnest shells and the least pulling resistance. P. staminea were eaten after the shells had been chipped or had been penetrated by drilling, presumably to inject a toxin. Likely because of these differences, octopuses consumed more V. philippinarum and M. trossulus than P. staminea when the mollusks were given to them either 1 species at a time or all together. However, when the shells were separated and the penetration problem removed, the octopuses predominantly chose P. staminea and nearly ignored M. trossulus. When V. philippinarum were wired shut, octopuses switched techniques. These results emphasize that octopuses can learn on the basis of nonvisual information and monitor their body position to carry out feeding actions.

  19. Spectrotypic analysis of IgM and IgA rheumatoid factors.

    PubMed Central

    Chu, J L; Gharavi, A E; Elkon, K B

    1986-01-01

    The spectrotypes of IgA and IgM rheumatoid factors (RF) were analysed in whole serum as well as immunoglobulin fractions and purified RF from patients with one of three autoimmune disorders. As predicted from the pI ranges of normal human serum IgM and IgA in agarose, IgM RF had near neutral pIs, whereas IgA RF showed more acidic (lower) pI values. Serum IgA and IgM RF from patients with rheumatoid arthritis or the sicca syndrome showed considerable charge heterogeneity whereas IgM RF from mixed cryoglobulinaemia or rheumatoid vasculitis patients showed monoclonal and oligoclonal banding patterns respectively. Clonotypic analysis was best achieved with isolated light and heavy chains from highly purified RF. The IgA RF spectrotypes from unmodified paired serum and saliva IgA were clearly different whereas after desialation, similar pI values and, in one case, similar spectrotypes were observed. These observations are compatible with the hypothesis that serum and saliva IgA RF are derived from similar clonal precursors. The methods used in these studies may also be of use in the analysis of IgA and IgM antibody diversity in a number of other situations. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:3708903

  20. The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms.

    PubMed

    Humphries, Austin T; La Peyre, Megan K; Decossas, Gary A

    2011-01-01

    Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and "predator-free space" to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of "predator-free space" was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require "predator-free space" measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of "predator-free space" are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.

  1. The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms

    USGS Publications Warehouse

    Humphries, Austin T.; La Peyre, Megan K.; Decossas, Gary A.

    2011-01-01

    Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and “predator-free space” to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of “predator-free space” was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require “predator-free space” measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of “predator-free space” are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.

  2. Levofloxacin Induced Toxic Epidermal Necrolysis: Successful Therapy with Omalizumab (Anti-IgE) and Pulse Prednisolone.

    PubMed

    Uzun, Rusen; Yalcin, Arzu Didem; Celik, Betul; Bulut, Tangul; Yalcin, Ata Nevzat

    2016-09-16

    BACKGROUND Toxic epidermal necrolysis (TEN) is characterized by widespread erythematous and bullous lesions on the skin. Nowadays, considerable progress has been made in the understanding of its pathogenesis. Immunologically it is similar to graft-versus-host disease. Therefore, we may propose that TEN is a disorder of cell-mediated immunity. CASE REPORT Our patient was a 74-year-old white female who had pneumonia and was positive for hepatitis C virus (HCV), and who had been on levofloxacin therapy. After the first levofloxacin dose, erythematous dusky red macules occurred on her extremities and trunk, and on the following day, confluent purpuric lesions tended to run together over 85% of her body. Her biopsy results indicated TEN. Laboratory testing for serum ECP (eosinophil cationic peptide) and serum immunoglobulin (Ig) levels were performed, and blister fluid was investigated. The patient responded positively to omalizumab treatment and after treatment laboratory tests revealed decreased high sensitive CRP, ECP, IgG1, IgG2, IgG3, IgG4, IgA, and IgM levels. CONCLUSIONS To the best of our knowledge, this is the first case of a patient with HCV who developed cutaneous adverse drug reaction on levofloxacin medication and recovered with omalizumab treatment. This is the first documentation of omalizumab treatment of a TEN patient.

  3. [IgG rheumatoid factor in rheumatoid arthritis with interstitial lung disease].

    PubMed

    Sakaida, H

    1995-08-01

    Case of rheumatoid arthritis (RA) with interstitial lung disease (ILD) have been reported to show increased titers of rheumatoid factor (RF) in serum; however the pathogenic role of this substance in the lung is still obscure. The aims of this study were to estimate IgGRF in the bronchoalveolar lavage fluid (BALF) in RA and to investigate its possible roles in the ILD of RA. Two step bronchoalveolar lavage in 20 RA patients (9 males, 11 females) was performed in conjunction with high resolution chest CT. IgGRF was measured by enzyme-linked immunosorbent assay and its molecular size in BALF was evaluated by high performance liquid chromatography. IgGRF bound to BALF cells was eluted by sonication of the cells. RA patients with ILD had significantly elevated levels of IgGRF in serum as well as in BALF. The IgGRF in BALF was monomeric in 2 of 3 RA patients with ILD. The activity of IgGRF bound to BALF cells was significantly higher in RA with ILD than in control patients. These findings suggest that monomeric IgGRF in the lungs of RA patients could bind to the cells with Fc receptors.

  4. Infant gut immunity: a preliminary study of IgA associations with breastfeeding.

    PubMed

    Bridgman, S L; Konya, T; Azad, M B; Sears, M R; Becker, A B; Turvey, S E; Mandhane, P J; Subbarao, P; Scott, J A; Field, C J; Kozyrskyj, A L

    2016-02-01

    Secretory immunoglobulin A (IgA) plays a critical role in gut mucosal immune defense. Initially provided by breastmilk, IgA production by the infant gut is gradually stimulated by developing gut microbiota. This study reports associations between infant fecal IgA concentrations 4 months after birth, breastfeeding status and other pre/postnatal exposures in 47 infants in the Canadian Healthy Infant Longitudinal Development cohort. Breastfed infants and first-born infants had higher median fecal IgA concentrations (23.11 v. 9.34 µg/g protein, P<0.01 and 22.19 v. 8.23 µg/g protein, P=0.04). IgA levels increased successively with exclusivity of breastfeeding (β-coefficient, 0.37, P<0.05). This statistical association was independent of maternal parity and household pets. In the absence of breastfeeding, female sex and pet exposure elevated fecal IgA to levels found in breastfed infants. In addition to breastfeeding, infant fecal IgA associations with pre/postnatal exposures may affect gut immunity and risk of allergic disease.

  5. [IgG4-related disease].

    PubMed

    Sato, Yasuharu; Yoshino, Tadashi

    2012-02-01

    IgG4-related disease is a recently recognized systemic syndrome characterized by mass-forming lesions, mainly in exocrine tissue, that consist of lymphoplasmacytic infiltrates and sclerosis. There are numerous IgG4+ plasma cells in the affected tissues, and the serum IgG4 level is elevated in these patients. Ocular adnexal IgG4-related disease frequently involves bilateral lacrimal glands, and obliterative phlebitis is rare. Moreover, some malignant lymphomas, especially mucosa-associated lymphoid tissue lymphoma, arise from ocular adnexal IgG4-related disease. It is known that hyper IL-6 syndromes, such as multicentric Castleman's disease, rheumatoid arthritis, and other autoimmune diseases, fulfill the histological diagnostic criteria for IgG4-related disease; therefore, hyper IL-6 syndromes and IgG4-related disease cannot be differentially diagnosed by immunohistochemical staining alone. However, upon laboratory examination, hype IL-6 syndromes show elevation of the CRP level, polyclonal hyper gamma-globulinemia, anemia, and hypoalbuminemia. These findings are quite different from IgG4-related disease, which is not characterized by elevated serum IgA, IgM, and CRP levels. Therefore, laboratory findings are crucial for the differential diagnosis.

  6. Pathogenesis of IgA nephropathy.

    PubMed

    Lai, Kar Neng

    2012-03-20

    Since its first description in 1968, IgA nephropathy has remained the most common form of idiopathic glomerulonephritis leading to chronic kidney disease in developed countries. The exact pathogenesis of IgA nephropathy is still not well defined. Current data implicate an important genetic factor, especially in promoting the overproduction of an aberrant form of IgA1. The immunochemical aberrancy of IgA nephropathy is characterized by the undergalactosylation of O-glycans in the hinge region of IgA1. However, such aberrant glycosylation alone does not cause renal injury. The next stage of disease development requires the formation of glycan-specific IgG and IgA antibodies that recognize the undergalactosylated IgA1 molecule. These antibodies often have reactivity against antigens from extrinsic microorganisms and might arise from recurrent mucosal infection. B cells that respond to mucosal infections, particularly tonsillitis, might produce the nephritogenic IgA1 molecule. With increased immune-complex formation and decreased clearance owing to reduced uptake by the liver, IgA1 binds to the glomerular mesangium via an as yet unidentified receptor. Glomerular IgA1 deposits trigger the local production of cytokines and growth factors, leading to the activation of mesangial cells and the complement system. Emerging data suggest that mesangial-derived mediators following glomerular deposition of IgA1 lead to podocyte and tubulointerstitial injury via mesangio-podocytic-tubular crosstalk. This Review summarizes the latest findings in the pathogenesis of IgA nephropathy.

  7. Factors Affecting Growth of Tengmalm’s Owl (Aegolius funereus) Nestlings: Prey Abundance, Sex and Hatching Order

    PubMed Central

    Zárybnická, Markéta; Riegert, Jan; Brejšková, Lucie; Šindelář, Jiří; Kouba, Marek; Hanel, Jan; Popelková, Alena; Menclová, Petra; Tomášek, Václav; Šťastný, Karel

    2015-01-01

    In altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. A number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. Based on a seven-year observational study in a central European Tengmalm’s owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mass and wing length, as well as the effect of prey abundance on parameters of growth curve. We found that nestling body mass varied among years, and parameters of growth curve, i.e. growth rate and inflection point in particular, increased with increasing abundance of the owl’s main prey (Apodemus mice, Microtus voles), and pooled prey abundance (Apodemus mice, Microtus voles, and Sorex shrews). Furthermore, nestling body mass varied with hatching order and between sexes being larger for females and for the first-hatched brood mates. Brood size had no effect on nestling body mass. Simultaneously, we found no effect of year, brood size, hatching order, or sex on the wing length of nestlings. Our findings suggest that in this temperate owl population, nestling body mass is more sensitive to prey abundance than is wing length. The latter is probably more limited by the physiology of the species. PMID:26444564

  8. Glomerular IgG deposition predicts renal outcome in patients with IgA nephropathy.

    PubMed

    Shin, Dong Ho; Lim, Beom Jin; Han, In Mi; Han, Seung Gyu; Kwon, Young Eun; Park, Kyoung Sook; Lee, Mi Jung; Oh, Hyung Jung; Park, Jung Tak; Han, Seung Hyeok; Kang, Shin-Wook; Yoo, Tae-Hyun

    2016-07-01

    Glomerular IgG deposition is frequently observed in patients with IgA nephropathy. However, the association between glomerular IgG deposition and progression of IgA nephropathy is uncertain. Six hundred and twenty-seven patients with biopsy-proven IgA nephropathy were recruited. Histological variables of the Oxford classification (Oxford-MEST) and the presence of glomerular IgG deposits were assessed. Renal progression defined as end-stage renal disease or 50% reduction in estimated glomerular filtration rate was analyzed using Kaplan-Meier methods and Cox regression analysis. Of the study population, 200 patients (31.9%) had glomerular IgG deposition on immunofluorescence staining. During a mean follow-up of 56.8±37.5 months, the rate of renal progression was significantly higher in the IgA nephropathy patients with glomerular IgG deposition compared with the IgA nephropathy patients without glomerular IgG deposition (39.8 vs 12.3 per 1000 patient-years; P<0.001). Of patients with IgG deposition, 178 (28.3%), 20 (3.2%), and 2 (0.3%) patients had mild, moderate, and marked glomerular IgG deposits, receptively. Kaplan-Meier analysis revealed that cumulative renal survival was significantly lower in IgA nephropathy patients with the higher intensity of glomerular IgG deposits (P<0.001). In addition, Cox regression analysis revealed that moderate and marked glomerular IgG deposits significantly predicted renal outcome independent of Oxford-MEST and clinical variables (HR, 2.97; 95% CI, 1.01-8.77; P=0.04). This study showed that that glomerular IgG deposition was independently associated with poor renal outcome in patient with IgA nephropathy.

  9. IgD positive L&H cells identify a unique subset of nodular lymphocyte predominant Hodgkin lymphoma.

    PubMed

    Prakash, Sonam; Fountaine, Thomas; Raffeld, Mark; Jaffe, Elaine S; Pittaluga, Stefania

    2006-05-01

    Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a rare B-cell lymphoma considered to be of germinal center (GC) derivation. Studies on immunoglobulin expression have been few, and post-switch immunoglobulin (IgG) has been identified in the majority of cases examined thus far. We reviewed 180 cases of NLPHL and observed the unexpected expression of IgD in 27% of cases. IgD is usually coexpressed with IgM in naive B cells but can also be seen as IgD-only in centroblasts (CD38-positive) or memory B cells (CD27-positive). We asked whether IgD-positive NLPHL differed from cases of NLPHL negative for IgD. Clinically, the IgD-positive cases presented at a younger median age (21 vs. 44 years) and had a striking male predominance (male-to-female ratio, 23:1 vs. 1.5:1). Cervical lymph nodes were more frequently involved (56% vs. 18.2%). L&H cells were localized in a predominantly extrafollicular distribution in the majority of IgD-positive cases (69%). The IgD-positive cases did not coexpress IgM or CD27 (a marker associated with memory B cells), and nearly all (93%) were weakly positive for CD38, supporting a GC derivation. The expression of Bcl-6, BOB.1, Oct2, and SWAP-70 was similar in the two groups. However, PU.1 expression was seen in 60% of the IgD-positive cases in contrast to 86% of the IgD-negative cases. The absence of PU.1 staining correlated with more L&H cells in an extrafollicular distribution, weakening the use of this marker in the differential diagnosis with T-cell rich/histiocyte rich B-cell lymphomas. To study IgD expression in "de-novo" T-cell rich/histiocyte rich B-cell lymphomas, we analyzed 20 cases and all but one were negative. In conclusion, cases of IgD-positive NLPHL do not differ from IgD-negative cases regarding cellular derivation and most other immunophenotypic characteristics. However, IgD-positive NLPHL exhibits distinctive clinical features, and more often involves the interfollicular region in a background relatively rich in T

  10. IgH loci of American alligator and saltwater crocodile shed light on IgA evolution.

    PubMed

    Magadán-Mompó, Susana; Sánchez-Espinel, Christian; Gambón-Deza, Francisco

    2013-07-01

    Immunoglobulin loci of two representatives of the order Crocodylia were studied from full genome sequences. Both Alligator mississippiensis and Crocodylus porosus have 13 genes for the heavy chain constant regions of immunoglobulins. The IGHC locus contains genes encoding four immunoglobulins M (IgM), one immunoglobulin D (IgD), three immunoglobulins A (IgA), three immunoglobulins Y (IgY), and two immunoglobulins D2 (IgD2). IgA and IgD2 genes were found in reverse transcriptional orientation compared to the other Ig genes. The IGHD gene contains 11 exons, four of which containing stop codons or sequence alterations. As described in other reptiles, the IgD2 is a chimeric Ig with IgA- and IgD-related domains. This work clarifies the origin of bird IgA and its evolutionary relationship with amphibian immunoglobulin X (IgX) as well as their links with mammalian IgA.

  11. Dynamics of prey prehension by chameleons through viscous adhesion

    NASA Astrophysics Data System (ADS)

    Brau, Fabian; Lanterbecq, Déborah; Zghikh, Leïla-Nastasia; Bels, Vincent; Damman, Pascal

    2016-10-01

    Among predators using an adhesive tongue to feed, chameleons are able to capture large prey by projecting the tongue at high acceleration. Once in contact with a prey, the tongue retracts with a comparable acceleration to bring it to the mouth. A strong adhesion between the tongue tip and the prey is therefore required during the retraction phase to ensure a successful capture. To investigate the mechanism responsible for this strong bond, the viscosity of the mucus produced at the chameleon's tongue pad is measured, using the viscous drag exerted on rolling beads by a thin layer of mucus. Here we show that the viscosity of this secretion is about 400 times larger than that of human saliva. We incorporate this viscosity into a dynamical model for viscous adhesion, which describes the motion of the compliant tongue and the prey during the retraction phase. The variation of the maximum prey size with respect to the chameleon body length is derived, and compared with in vivo observations for various chameleon species. Our study shows that the size of the captured prey is not limited by viscous adhesion, owing to the high mucus viscosity and large contact area between the prey and the tongue.

  12. Tactile experience shapes prey-capture behavior in Etruscan shrews

    PubMed Central

    Anjum, Farzana; Brecht, Michael

    2012-01-01

    A crucial role of tactile experience for the maturation of neural response properties in the somatosensory system is well established, but little is known about the role of tactile experience in the development of tactile behaviors. Here we study how tactile experience affects prey capture behavior in Etruscan shrews, Suncus etruscus. Prey capture in adult shrews is a high-speed behavior that relies on precise attacks guided by tactile Gestalt cues. We studied the role of tactile experience by three different approaches. First, we analyzed the hunting skills of young shrews' right after weaning. We found that prey capture in young animals in most, but not all, aspects is similar to that of adults. Second, we performed whisker trimming for 3–4 weeks after birth. Such deprivation resulted in a lasting disruption of prey capture even after whisker re-growth: attacks lacked precise targeting and had a lower success rate. Third, we presented adult shrews with an entirely novel prey species, the giant cockroach. The shape of this roach is very different from the shrew's normal (cricket) prey and the thorax—the preferred point of attack in crickets—is protected by a heavy cuticle. Initially shrews attacked giant roaches the same way they attack crickets and targeted the thoracic region. With progressive experience, however, shrews adopted a new attack strategy targeting legs and underside of the roaches while avoiding other body parts. Speed and efficiency of attacks improved. These data suggest that tactile experience shapes prey capture behavior. PMID:22701408

  13. A snail-eating snake recognizes prey handedness

    PubMed Central

    Danaisawadi, Patchara; Asami, Takahiro; Ota, Hidetoshi; Sutcharit, Chirasak; Panha, Somsak

    2016-01-01

    Specialized predator-prey interactions can be a driving force for their coevolution. Southeast Asian snail-eating snakes (Pareas) have more teeth on the right mandible and specialize in predation on the clockwise-coiled (dextral) majority in shelled snails by soft-body extraction. Snails have countered the snakes’ dextral-predation by recurrent coil reversal, which generates diverse counterclockwise-coiled (sinistral) prey where Pareas snakes live. However, whether the snake predator in turn evolves any response to prey reversal is unknown. We show that Pareas carinatus living with abundant sinistrals avoids approaching or striking at a sinistral that is more difficult and costly to handle than a dextral. Whenever it strikes, however, the snake succeeds in predation by handling dextral and sinistral prey in reverse. In contrast, P. iwasakii with little access to sinistrals on small peripheral islands attempts and frequently misses capturing a given sinistral. Prey-handedness recognition should be advantageous for right-handed snail-eating snakes where frequently encountering sinistrals. Under dextral-predation by Pareas snakes, adaptive fixation of a prey population for a reversal gene instantaneously generates a sinistral species because interchiral mating is rarely possible. The novel warning, instead of sheltering, effect of sinistrality benefitting both predators and prey could further accelerate single-gene ecological speciation by left-right reversal. PMID:27046345

  14. Predator pursuit strategies: how do falcons and hawks chase prey?

    NASA Astrophysics Data System (ADS)

    Kane, Suzanne Amador; Zamani, Marjon; Fulton, Andrew; Rosenthal, Lee

    2014-03-01

    This study reports on experiments on falcons, goshawks and red-tailed hawks wearing miniature videocameras mounted on their backs or heads while pursuing flying or ground-based prey. Videos of hunts recorded by the raptors were analyzed to determine apparent prey positions on their visual fields during pursuits. These video data then were interpreted using computer simulations of pursuit steering laws observed in insects and mammals. A comparison of the empirical and modeling data indicates that falcons use cues due to the apparent motion of prey on the falcon's visual field to track and capture flying prey via a form of motion camouflage. The falcons also were found to maintain their prey's image at visual angles consistent with using their shallow fovea. Results for goshawks and red-tailed hawks were analyzed for a comparative study of how pursuits of ground-based prey by accipeters and buteos differ from those used by falcons chasing flying prey. These results should prove relevant for understanding the coevolution of pursuit and evasion, as well as the development of computer models of predation on flocks,and the integration of sensory and locomotion systems in biomimetic robots.

  15. Disentangling mite predator-prey relationships by multiplex PCR.

    PubMed

    Pérez-Sayas, Consuelo; Pina, Tatiana; Gómez-Martínez, María A; Camañes, Gemma; Ibáñez-Gual, María V; Jaques, Josep A; Hurtado, Mónica A

    2015-11-01

    Gut content analysis using molecular techniques can help elucidate predator-prey relationships in situations in which other methodologies are not feasible, such as in the case of trophic interactions between minute species such as mites. We designed species-specific primers for a mite community occurring in Spanish citrus orchards comprising two herbivores, the Tetranychidae Tetranychus urticae and Panonychus citri, and six predatory mites belonging to the Phytoseiidae family; these predatory mites are considered to be these herbivores' main biological control agents. These primers were successfully multiplexed in a single PCR to test the range of predators feeding on each of the two prey species. We estimated prey DNA detectability success over time (DS50), which depended on the predator-prey combination and ranged from 0.2 to 18 h. These values were further used to weight prey detection in field samples to disentangle the predatory role played by the most abundant predators (i.e. Euseius stipulatus and Phytoseiulus persimilis). The corrected predation value for E. stipulatus was significantly higher than for P. persimilis. However, because this 1.5-fold difference was less than that observed regarding their sevenfold difference in abundance, we conclude that P. persimilis is the most effective predator in the system; it preyed on tetranychids almost five times more frequently than E. stipulatus did. The present results demonstrate that molecular tools are appropriate to unravel predator-prey interactions in tiny species such as mites, which include important agricultural pests and their predators.

  16. Tactile experience shapes prey-capture behavior in Etruscan shrews.

    PubMed

    Anjum, Farzana; Brecht, Michael

    2012-01-01

    A crucial role of tactile experience for the maturation of neural response properties in the somatosensory system is well established, but little is known about the role of tactile experience in the development of tactile behaviors. Here we study how tactile experience affects prey capture behavior in Etruscan shrews, Suncus etruscus. Prey capture in adult shrews is a high-speed behavior that relies on precise attacks guided by tactile Gestalt cues. We studied the role of tactile experience by three different approaches. First, we analyzed the hunting skills of young shrews' right after weaning. We found that prey capture in young animals in most, but not all, aspects is similar to that of adults. Second, we performed whisker trimming for 3-4 weeks after birth. Such deprivation resulted in a lasting disruption of prey capture even after whisker re-growth: attacks lacked precise targeting and had a lower success rate. Third, we presented adult shrews with an entirely novel prey species, the giant cockroach. The shape of this roach is very different from the shrew's normal (cricket) prey and the thorax-the preferred point of attack in crickets-is protected by a heavy cuticle. Initially shrews attacked giant roaches the same way they attack crickets and targeted the thoracic region. With progressive experience, however, shrews adopted a new attack strategy targeting legs and underside of the roaches while avoiding other body parts. Speed and efficiency of attacks improved. These data suggest that tactile experience shapes prey capture behavior.

  17. Flexibility in assessment of prey cues: frog-eating bats and frog calls.

    PubMed

    Page, Rachel A; Ryan, Michael J

    2005-04-22

    Predators use cues associated with their prey to assess prey quality and to avoid consuming poisonous prey. Considerable attention has been given to predators' use of aposematic cues to assess prey quality, but little is known about predators that eavesdrop on prey cues that are not intended for them. Here we investigate the prey-cue/prey-quality associations of a predator that eavesdrops on the sexual advertisement signals of its prey. Stability is expected in prey-cue/prey-quality associations when mistakes in prey assessment are lethal. Conversely, flexibility is possible when mistakes are less costly. Predators that must respond to temporal and spatial fluctuations in prey availability should be more flexible in their assessment of prey quality. Given these predictions, we examined flexibility in the ability of wild-caught bats to reverse prey-cue/prey-quality associations for a preferred prey and a poisonous one. We found that the predatory bat, Trachops cirrhosus, has a heretofore undescribed ability to reverse its evaluations of the cues that signal preferred prey.

  18. Predicting prey population dynamics from kill rate, predation rate and predator-prey ratios in three wolf-ungulate systems.

    PubMed

    Vucetich, John A; Hebblewhite, Mark; Smith, Douglas W; Peterson, Rolf O

    2011-11-01

    1. Predation rate (PR) and kill rate are both fundamental statistics for understanding predation. However, relatively little is known about how these statistics relate to one another and how they relate to prey population dynamics. We assess these relationships across three systems where wolf-prey dynamics have been observed for 41 years (Isle Royale), 19 years (Banff) and 12 years (Yellowstone). 2. To provide context for this empirical assessment, we developed theoretical predictions of the relationship between kill rate and PR under a broad range of predator-prey models including predator-dependent, ratio-dependent and Lotka-Volterra dynamics. 3. The theoretical predictions indicate that kill rate can be related to PR in a variety of diverse ways (e.g. positive, negative, unrelated) that depend on the nature of predator-prey dynamics (e.g. structure of the functional response). These simulations also suggested that the ratio of predator-to-prey is a good predictor of prey growth rate. That result motivated us to assess the empirical relationship between the ratio and prey growth rate for each of the three study sites. 4. The empirical relationships indicate that PR is not well predicted by kill rate, but is better predicted by the ratio of predator-to-prey. Kill rate is also a poor predictor of prey growth rate. However, PR and ratio of predator-to-prey each explained significant portions of variation in prey growth rate for two of the three study sites. 5. Our analyses offer two general insights. First, Isle Royale, Banff and Yellowstone are similar insomuch as they all include wolves preying on large ungulates. However, they also differ in species diversity of predator and prey communities, exploitation by humans and the role of dispersal. Even with the benefit of our analysis, it remains difficult to judge whether to be more impressed by the similarities or differences. This difficulty nicely illustrates a fundamental property of ecological

  19. Predator cannibalism can intensify negative impacts on heterospecific prey.

    PubMed

    Takatsu, Kunio; Kishida, Osamu

    2015-07-01

    Although natural populations consist of individuals with different traits, and the degree of phenotypic variation varies among populations, the impact of phenotypic variation on ecological interactions has received little attention, because traditional approaches to community ecology assume homogeneity of individuals within a population. Stage structure, which is a common way of generating size and developmental variation within predator populations, can drive cannibalistic interactions, which can affect the strength of predatory effects on the predator's heterospecific prey. Studies have shown that predator cannibalism weakens predatory effects on heterospecific prey by reducing the size of the predator population and by inducing less feeding activity of noncannibal predators. We predict, however, that predator cannibalism, by promoting rapid growth of the cannibals, can also intensify predation pressure on heterospecific prey, because large predators have large resource requirements and may utilize a wider variety of prey species. To test this hypothesis, we conducted an experiment in which we created carnivorous salamander (Hynobius retardatus) populations with different stage structures by manipulating the salamander's hatch timing (i.e., populations with large or small variation in the timing of hatching), and explored the resultant impacts on the abundance, behavior, morphology, and life history of the salamander's large heterospecific prey, Rana pirica frog tadpoles. Cannibalism was rare in salamander populations having small hatch-timing variation, but was frequent in those having large hatch-timing variation. Thus, giant salamander cannibals occurred only in the latter. We clearly showed that salamander giants exerted strong predation pressure on frog tadpoles, which induced large behavioral and morphological defenses in the tadpoles and caused them to metamorphose late at large size. Hence, predator cannibalism arising from large variation in the timing

  20. Birth timing for mountain lions (Puma concolor); testing the prey availability hypothesis.

    PubMed

    Jansen, Brian D; Jenks, Jonathan A

    2012-01-01

    We investigated potential advantages in birth timing for mountain lion (Puma concolor) cubs. We examined cub body mass, survival, and age of natal dispersal in relation to specific timing of birth. We also investigated the role of maternal age relative to timing of births. We captured mountain lion cubs while in the natal den to determine birth date, which allowed for precise estimates of the population birth pulse and age of natal dispersal. A birth pulse occurred during June-August. Body mass of cubs was related to litter size and timing of birth; heaviest cubs occurred in litters of 2, and those born after 1 July. Cubs born within pulse months exhibited similar survival to those born out of the pulse. We found that cubs born April-June dispersed at younger ages than those born after 1 July. There was less variation in birth timing for 1(st) litters of females than older females. We hypothesize that cubs born after the peak in births of neonate prey are advantaged by the abundance of vulnerable prey and those cubs and mothers realize an evolutionary advantage.

  1. A multiple phenotype predator-prey model with mutation

    NASA Astrophysics Data System (ADS)

    Abernethy, Gavin M.; Mullan, Rory; Glass, David H.; McCartney, Mark

    2017-01-01

    An existing multiple phenotype predator-prey model is expanded to include mutation amongst the predator phenotypes. Two unimodal maps are used for the underlying dynamics of the prey. A predation strategy is also defined which differs for each of the predators in the model. Results show that the introduction of predator mutation enhances predator survival both in terms of the number of phenotypes and total population for a range of values of the predation rate. In general, the dominant predator phenotype is the one which is most focused on the prey phenotype with the largest population.

  2. The Role of Motion Extrapolation in Amphibian Prey Capture

    PubMed Central

    2015-01-01

    Sensorimotor delays decouple behaviors from the events that drive them. The brain compensates for these delays with predictive mechanisms, but the efficacy and timescale over which these mechanisms operate remain poorly understood. Here, we assess how prediction is used to compensate for prey movement that occurs during visuomotor processing. We obtained high-speed video records of freely moving, tongue-projecting salamanders catching walking prey, emulating natural foraging conditions. We found that tongue projections were preceded by a rapid head turn lasting ∼130 ms. This motor lag, combined with the ∼100 ms phototransduction delay at photopic light levels, gave a ∼230 ms visuomotor response delay during which prey typically moved approximately one body length. Tongue projections, however, did not significantly lag prey position but were highly accurate instead. Angular errors in tongue projection accuracy were consistent with a linear extrapolation model that predicted prey position at the time of tongue contact using the average prey motion during a ∼175 ms period one visual latency before the head movement. The model explained successful strikes where the tongue hit the fly, and unsuccessful strikes where the fly turned and the tongue hit a phantom location consistent with the fly's earlier trajectory. The model parameters, obtained from the data, agree with the temporal integration and latency of retinal responses proposed to contribute to motion extrapolation. These results show that the salamander predicts future prey position and that prediction significantly improves prey capture success over a broad range of prey speeds and light levels. SIGNIFICANCE STATEMENT Neural processing delays cause actions to lag behind the events that elicit them. To cope with these delays, the brain predicts what will happen in the future. While neural circuits in the retina and beyond have been suggested to participate in such predictions, few behaviors have been

  3. Cannibalism in discrete-time predator-prey systems.

    PubMed

    Chow, Yunshyong; Jang, Sophia R-J

    2012-01-01

    In this study, we propose and investigate a two-stage population model with cannibalism. It is shown that cannibalism can destabilize and lower the magnitude of the interior steady state. However, it is proved that cannibalism has no effect on the persistence of the population. Based on this model, we study two systems of predator-prey interactions where the prey population is cannibalistic. A sufficient condition based on the nontrivial boundary steady state for which both populations can coexist is derived. It is found via numerical simulations that introduction of the predator population may either stabilize or destabilize the prey dynamics, depending on cannibalism coefficients and other vital parameters.

  4. IgA Structure Variations Associate with Immune Stimulations and IgA Mesangial Deposition.

    PubMed

    Oruc, Zeliha; Oblet, Christelle; Boumediene, Ahmed; Druilhe, Anne; Pascal, Virginie; Le Rumeur, Elisabeth; Cuvillier, Armelle; El Hamel, Chahrazed; Lecardeur, Sandrine; Leanderson, Tomas; Morelle, Willy; Demengeot, Jocelyne; Aldigier, Jean-Claude; Cogné, Michel

    2016-09-01

    IgA1 mesangial deposition is the hallmark of IgA nephropathy and Henoch-Schönlein purpura, the onset of which often follows infections. Deposited IgA has been reported as polymeric, J chain associated, and often, hypogalactosylated but with no information concerning the influence of the IgA repertoire or the link between immune stimuli and IgA structure. We explored these issues in the α1KI mouse model, which produces polyclonal human IgA1 prone to mesangial deposition. Compared with mice challenged by a conventional environment, mice in a specific pathogen-free environment had less IgA deposition. However, serum IgA of specific pathogen-free mice showed more galactosylation and much lower polymerization. Notably, wild-type, α1KI, and even J chain-deficient mice showed increased polymeric serum IgA on exposure to pathogens. Strict germfree conditions delayed but did not completely prevent deposition; mice housed in these conditions had very low serum IgA levels and produced essentially monomeric IgA. Finally, comparing monoclonal IgA1 that had different variable regions and mesangial deposition patterns indicated that, independently of glycosylation and polymerization, deposition might also depend on IgA carrying specific variable domains. Together with IgA quantities and constant region post-translational modifications, repertoire changes during immune responses might, thus, modulate IgA propensity to deposition. These IgA features are not associated with circulating immune complexes and C3 deposition and are more pertinent to an initial IgA deposition step preceding overt clinical symptoms in patients.

  5. IgM, IgD and IgY and their expression pattern in the Chinese soft-shelled turtle Pelodiscus sinensis.

    PubMed

    Xu, Zhen; Wang, Gai L; Nie, P

    2009-06-01

    Three Ig isotypes, IgM, IgD, and IgA, were previously known in reptiles. Here, in this report we describe IgM, IgD and a novel immunoglobulin heavy-chain isotype upsilon (IgY) in Chinese soft-shelled turtle (Pelodiscus sinensis). The IgM and IgY constant domains are characteristically similar to their counterparts described in other vertebrates. The expression of IgM and IgD were detected at mRNA level early during embryonic development, and their expression increased during further development. However, the IgY expression was not detected in larval turtles until 90 days after hatching-out. The increase in the transcription of these three Ig molecules was analyzed by using real-time PCR in spleen, kidney and blood following the injection of inactivated Aeromonas hydrophila. The primary increase in the expression of these three Igs was observed 1 week after the first injection, although not statistically significant, and the second injection 2 weeks after the first injection provoked a significant increase in the expression of these Igs, revealing a pattern of primary and secondary antibody response in the turtle. The present study represents the first report on reptile IgY and the pattern of IgM, IgD and IgY transcription in reptiles.

  6. IgG4-related skin disease.

    PubMed

    Tokura, Y; Yagi, H; Yanaguchi, H; Majima, Y; Kasuya, A; Ito, T; Maekawa, M; Hashizume, H

    2014-11-01

    IgG4-related disease (IgG4-RD) is a recently established clinical entity characterized by high levels of circulating IgG4, and tissue infiltration of IgG4(+) plasma cells. IgG4-RD exhibits a distinctive fibroinflammatory change involving multiple organs, such as the pancreas and salivary and lacrimal glands. The skin lesions of IgG4-RD have been poorly characterized and may stem not only from direct infiltration of plasma cells but also from IgG4-mediated inflammation. Based on the documented cases together with ours, we categorized the skin lesions into seven subtypes: (1) cutaneous plasmacytosis (multiple papulonodules or indurations on the trunk and proximal part of the limbs), (2) pseudolymphoma and angiolymphoid hyperplasia with eosinophilia (plaques and papulonodules mainly on the periauricular, cheek and mandible regions), (3) Mikulicz disease (palpebral swelling, sicca syndrome and exophthalmos), (4) psoriasis-like eruption (strikingly mimicking psoriasis vulgaris), (5) unspecified maculopapular or erythematous eruptions, (6) hypergammaglobulinaemic purpura (bilateral asymmetrical palpable purpuric lesions on the lower extremities) and urticarial vasculitis (prolonged urticarial lesions occasionally with purpura) and (7) ischaemic digit (Raynaud phenomenon and digital gangrene). It is considered that subtypes 1-3 are induced by direct infiltration of IgG4(+) plasma cells, while the other types (4-7) are caused by secondary mechanisms. IgG4-related skin disease is defined as IgG4(+) plasma-cell-infiltrating skin lesions that form plaques, nodules or tumours (types 1-3), but may manifest secondary lesions caused by IgG4(+) plasma cells and/or IgG4 (types 4-7).

  7. Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality.

    PubMed

    Bijleveld, Allert I; MacCurdy, Robert B; Chan, Ying-Chi; Penning, Emma; Gabrielson, Rich M; Cluderay, John; Spaulding, Eric L; Dekinga, Anne; Holthuijsen, Sander; ten Horn, Job; Brugge, Maarten; van Gils, Jan A; Winkler, David W; Piersma, Theunis

    2016-04-13

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The 'functional response' couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotically with prey density; this predicts the highest predator densities at the highest prey densities. In one of the most stringent tests of this generality to date, we measured density and quality of bivalve prey (edible cockles Cerastoderma edule) across 50 km² of mudflat, and simultaneously, with a novel time-of-arrival methodology, tracked their avian predators (red knots Calidris canutus). Because of negative density-dependence in the individual quality of cockles, the predicted energy intake rates of red knots declined at high prey densities (a type IV, rather than a type II functional response). Resource-selection modelling revealed that red knots indeed selected areas of intermediate cockle densities where energy intake rates were maximized given their phenotype-specific digestive constraints (as indicated by gizzard mass). Because negative density-dependence is common, we question the current consensus and suggest that predators commonly maximize their energy intake rates at intermediate prey densities. Prey density alone may thus poorly predict intake rates, carrying capacity and spatial distributions of predators.

  8. Sizes of prey consumed by two pelagic predators in US reservoirs: Implications for quantifying biomass of available prey

    USGS Publications Warehouse

    Dennerline, D.E.; Van Den Avyle, M.J.

    2000-01-01

    Striped bass Morone saxatilis and hybrid bass M. saxatilis x M. chrysops have been stocked to establish fisheries in many US reservoirs, but success has been limited by a poor understanding of relations between prey biomass and predator growth and survival. To define sizes of prey that are morphologically available, we developed predictive relationships between predator length, mouth dimensions, and expected maximum prey size; predictions were then validated using published data on sizes of clupeid prey (Dorosoma spp.) in five US reservoirs. Further, we compared the biomass of prey considered available to predators using two forms of a length-based consumption model - a previously published AP/P ratio and a revised model based on our results. Predictions of maximum prey size using predator GW were consistent with observed prey sizes in US reservoirs. Length of consumed Dorosoma was significantly, but weakly, correlated with predator length in four of the five reservoirs (r2 = 0.006-0.336, P 150 mm TL) were abundant. (C) 2000 Elsevier Science B.V.

  9. Cell-cycle progress in obligate predatory bacteria is dependent upon sequential sensing of prey recognition and prey quality cues

    PubMed Central

    Rotem, Or; Pasternak, Zohar; Shimoni, Eyal; Belausov, Eduard; Porat, Ziv; Pietrokovski, Shmuel; Jurkevitch, Edouard

    2015-01-01

    Predators feed on prey to acquire the nutrients necessary to sustain their survival, growth, and replication. In Bdellovibrio bacteriovorus, an obligate predator of Gram-negative bacteria, cell growth and replication are tied to a shift from a motile, free-living phase of search and attack to a sessile, intracellular phase of growth and replication during which a single prey cell is consumed. Engagement and sustenance of growth are achieved through the sensing of two unidentified prey-derived cues. We developed a novel ex vivo cultivation system for B. bacteriovorus composed of prey ghost cells that are recognized and invaded by the predator. By manipulating their content, we demonstrated that an early cue is located in the prey envelope and a late cue is found within the prey soluble fraction. These spatially and temporally separated cues elicit discrete and combinatory regulatory effects on gene transcription. Together, they delimit a poorly characterized transitory phase between the attack phase and the growth phase, during which the bdelloplast (the invaded prey cell) is constructed. This transitory phase constitutes a checkpoint in which the late cue presumably acts as a determinant of the prey’s nutritional value before the predator commits. These regulatory adaptations to a unique bacterial lifestyle have not been reported previously. PMID:26487679

  10. Sensory exploitation of prey: manipulation of the initial direction of prey escapes by a conspicuous "rare enemy".

    PubMed

    Jabłonski, P G

    2001-05-22

    The painted redstart (Myioborus pictus) represents a group of non-cryptic predators, the flush pursuers, who visually trigger prey escapes by spreading and pivoting their conspicuously patterned tails and wings. The prey are then chased in aerial pursuits. Such an exploitation of prey may be possible because the predation risk from redstarts is smaller than that from the predatory guild of insectivores and their neural pathways are adapted to helping prey avoid common predators rather than "rare enemies". I propose that the pivoting movements of flush pursuers direct insect escapes across the central field of vision of a predator, where it is easier to track and intercept the prey. Eighty per cent of chases by wild redstarts were in a direction suggesting that prey were entering the birds' area of stereoscopic vision. The redstart's fanned and raised tail creates a stronger visual stimulus than a redstart's head. Flies escaped away from the section of the fly's field of vision in which the model's tail was located and towards the area where the predator's stereoscopic vision is likely to be located, in front of a bird's forehead. The experiments suggested that redstarts may not only exploit the sensitivity of typical neural escape pathways, which are non-directionally sensitive, but that they may also exploit the sensitivity of some directionally sensitive neural pathways in prey.

  11. Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality

    PubMed Central

    Chan, Ying-Chi; Penning, Emma; Cluderay, John; Spaulding, Eric L.; Dekinga, Anne; ten Horn, Job; Brugge, Maarten; Winkler, David W.

    2016-01-01

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The ‘functional response’ couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotically with prey density; this predicts the highest predator densities at the highest prey densities. In one of the most stringent tests of this generality to date, we measured density and quality of bivalve prey (edible cockles Cerastoderma edule) across 50 km² of mudflat, and simultaneously, with a novel time-of-arrival methodology, tracked their avian predators (red knots Calidris canutus). Because of negative density-dependence in the individual quality of cockles, the predicted energy intake rates of red knots declined at high prey densities (a type IV, rather than a type II functional response). Resource-selection modelling revealed that red knots indeed selected areas of intermediate cockle densities where energy intake rates were maximized given their phenotype-specific digestive constraints (as indicated by gizzard mass). Because negative density-dependence is common, we question the current consensus and suggest that predators commonly maximize their energy intake rates at intermediate prey densities. Prey density alone may thus poorly predict intake rates, carrying capacity and spatial distributions of predators. PMID:27053747

  12. IgG4-related nephropathy.

    PubMed

    Quattrocchio, Giacomo; Roccatello, Dario

    2016-08-01

    IgG4-related disease (IgG4-RD) is a recently recognized disorder, often with multiple organ involvement, characterized by dense tissue infiltration of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis and frequently elevated serum IgG4 concentration. The kidney can be involved either directly or indirectly. The most frequent direct renal manifestations of IgG4-RD are IgG4-related tubulointerstitial nephritis (TIN) and membranous glomerulonephropathy. Retroperitoneal fibrosis (RPF) is another condition that is frequently IgG4-related and that can indirectly affect the kidney causing ureteral obstruction and hydronephrosis. Contrast-enhanced computerized tomography, magnetic resonance imaging and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography show different imaging findings and are useful tools for monitoring therapeutic response. Steroid treatment is the first line of therapy, but relapsing or refractory forms of the disease are frequently observed and require more aggressive therapeutic approaches. At our centre, we treated three cases of aggressive IgG4-related TIN and two cases of IgG4-related RPF with an intensified, immune suppressive protocol, obtaining good results without severe adverse effects.

  13. Trophic relay and prey switching - A stomach contents and calorimetric investigation of an ambassid fish and their saltmarsh prey

    NASA Astrophysics Data System (ADS)

    McPhee, Jack J.; Platell, Margaret E.; Schreider, Maria J.

    2015-12-01

    Trophic relay is an ecological model that involves the movement of biomass and energy from vegetation, such as saltmarshes, within estuaries to the open sea via a series of predator-prey relationships. Any potential for trophic relay is therefore affected by water movements within an estuary and by the ability of a predator to "switch" prey in response to fluctuating abundances of those prey. Saltmarsh-dwelling grapsid crabs, which feed on saltmarsh-derived detritus and microphytobenthos, release zoeae into ebbing tides that inundate saltmarshes during spring-tide cycles within tidally-dominated estuaries, such as Brisbane Water Estuary, therefore providing an opportunity to examine whether prey-switching and/or trophic relay may occur in fish that feed on those zoeae (such as the highly abundant estuarine ambassid, Ambassis jacksoniensis). This model was examined by sampling A. jacksoniensis near saltmarshes in a large, temperate south-eastern Australian estuary during flood and ebb tides on days of saltmarsh inundation and non-inundation over four spring-tide events in 2012. Stomach fullnesses of A. jacksoniensis were generally highest during ebb tides on days of saltmarsh inundation, implying that feeding was most marked at these times. Caridean decapods dominated diets during flood tides and on days of no saltmarsh inundation, while crab zoeae dominated diets during ebb tides and on days of inundation, suggesting that, when saltmarsh-derived zoeae became abundant, A. jacksoniensis switched to feeding on those prey. Three potential zooplankton prey (calanoid copepods, caridean decapods and crab zoeae) did not differ calorimetrically, indicating that switching of prey by A. jacksoniensis is not directly related to their preying on energetically greater prey, but reflects opportunistic feeding on more abundant and/or less elusive prey. As A. jacksoniensis is able to switch prey from estuarine caridean decapods to saltmarsh-derived crab zoeae, this very abundant

  14. Simultaneous Quantification of Anticardiolipin IgG and IgM by Time Resolved Fluoroimmunoassay

    PubMed Central

    Liu, Jie; Li, Mei; Ye, Yan; Chen, Yu

    2016-01-01

    The autoimmune disease antiphospholipid syndrome (APS) is characterized by the presence of anticardiolipin antibodies (aCL), along with anti-β2-glycoprotein I (β2GPI) antibodies and lupus anticoagulant (LA). In this study, we developed a time-resolved fluoroimmunoassay (TRFIA) system for simultaneous quantification of aCL IgG and IgM. A 96-well microtiter plate precoated with the complex of cardiolipin from bovine heart and bovine β2GPI was incubated with the anticardiolipin IgG and IgM standard substance or serum, and the conjugate of Eu3+-labeled anti-human IgG and Sm3+-labeled anti-human IgM was pipetted to the wells to form a tipical double-antibody-sandwich immunoreactions; finally the fluorescent intensity of Eu3+ and Sm3+ was detected to reflect the quantity of anticardiolipin IgG and IgM. This assay showed a good relationship between fluorescence intensities and the concentration of anticardiolipin antibody(aCL) IgG and IgM, with a low-end sensitivity of 0.1 U/ml for IgG and 0.1 U/ml for IgM, respectively. The intra- and inter-assay coefficients of variation (CV) of the calibrators was 3.0% and 4.51% for IgG, and 2.76% and 4.45% for IgM. The average recovery was 100.38% for aCL IgG and 100.45% for aCL IgM. For serum samples, the results of our method showed a good correlation with those obtained with ELISA kit. Simultaneous detection of aCL-IgG and aCL-IgM in the same reaction well can optimize assay performance by avoiding potential influence of different reaction conditions-timing, and well-to-well difference in concentration and characteristics of cardiolipin antigen. The results of a combo aCL-IgG and aCL-IgM assay for the same sample are more consistent and more reliable. This dual-label time-resolved fluoroimmunoassay is sensitive for detecting aCL IgG and IgM across a wide concentration range with stable reagents and may assist in the clinical diagnosis of antiphospholipid syndrome. PMID:27661084

  15. Transglutaminase is essential for IgA nephropathy development acting through IgA receptors.

    PubMed

    Berthelot, Laureline; Papista, Christina; Maciel, Thiago T; Biarnes-Pelicot, Martine; Tissandie, Emilie; Wang, Pamela H M; Tamouza, Houda; Jamin, Agnès; Bex-Coudrat, Julie; Gestin, Aurelie; Boumediene, Ahmed; Arcos-Fajardo, Michelle; England, Patrick; Pillebout, Evangéline; Walker, Francine; Daugas, Eric; Vrtosvnik, François; Flamant, Martin; Benhamou, Marc; Cogné, Michel; Moura, Ivan C; Monteiro, Renato C

    2012-04-09

    IgA nephropathy (IgAN) is a common cause of renal failure worldwide. Treatment is limited because of a complex pathogenesis, including unknown factors favoring IgA1 deposition in the glomerular mesangium. IgA receptor abnormalities are implicated, including circulating IgA-soluble CD89 (sCD89) complexes and overexpression of the mesangial IgA1 receptor, TfR1 (transferrin receptor 1). Herein, we show that although mice expressing both human IgA1 and CD89 displayed circulating and mesangial deposits of IgA1-sCD89 complexes resulting in kidney inflammation, hematuria, and proteinuria, mice expressing IgA1 only displayed endocapillary IgA1 deposition but neither mesangial injury nor kidney dysfunction. sCD89 injection into IgA1-expressing mouse recipients induced mesangial IgA1 deposits. sCD89 was also detected in patient and mouse mesangium. IgA1 deposition involved a direct binding of sCD89 to mesangial TfR1 resulting in TfR1 up-regulation. sCD89-TfR1 interaction induced mesangial surface expression of TGase2 (transglutaminase 2), which in turn up-regulated TfR1 expression. In the absence of TGase2, IgA1-sCD89 deposits were dramatically impaired. These data reveal a cooperation between IgA1, sCD89, TfR1, and TGase2 on mesangial cells needed for disease development. They demonstrate that TGase2 is responsible for a pathogenic amplification loop facilitating IgA1-sCD89 deposition and mesangial cell activation, thus identifying TGase2 as a target for therapeutic intervention in this disease.

  16. Colour Polymorphism Protects Prey Individuals and Populations Against Predation.

    PubMed

    Karpestam, Einat; Merilaita, Sami; Forsman, Anders

    2016-02-23

    Colour pattern polymorphism in animals can influence and be influenced by interactions between predators and prey. However, few studies have examined whether polymorphism is adaptive, and there is no evidence that the co-occurrence of two or more natural prey colour variants can increase survival of populations. Here we show that visual predators that exploit polymorphic prey suffer from reduced performance, and further provide rare evidence in support of the hypothesis that prey colour polymorphism may afford protection against predators for both individuals and populations. This protective effect provides a probable explanation for the longstanding, evolutionary puzzle of the existence of colour polymorphisms. We also propose that this protective effect can provide an adaptive explanation for search image formation in predators rather than search image formation explaining polymorphism.

  17. Prey-predator communication: for your sensors only.

    PubMed

    Page, Rachel A

    2007-11-20

    Prey have evolved myriad strategies to escape predation. Ground squirrels tailor their defensive signals to the predator at hand and use infrared warning signals in response to heat-sensitive rattlesnakes.

  18. Spatiotemporal predictability of schooling and nonschooling prey of Pigeon Guillemots

    USGS Publications Warehouse

    Litzow, Michael A.; Piatt, John F.; Abookire, Alisa A.; Speckman, Suzann G.; Arimitsu, Mayumi L.; Figurski, Jared D.

    2004-01-01

    Low spatiotemporal variability in the abundance of nonschooling prey might allow Pigeon Guillemots (Cepphus columba) to maintain the high chick provisioning rates that are characteristic of the species. We tested predictions of this hypothesis with data collected with beach seines and scuba and hydroacoustic surveys in Kachemak Bay, Alaska, during 1996–1999. Coefficients of variability were 20–211% greater for schooling than nonschooling prey on day, seasonal, and km scales. However, the proportion of schooling prey in chick diets explained relatively little variability in Pigeon Guillemot meal delivery rates at the scale of hours (r2 = 0.07) and weeks (r2 = 0.19). Behavioral adaptations such as flexible time budgets likely ameliorate the negative effects of high resource variability, but we propose that these adaptations are only effective when schooling prey are available at distances well below the maximum foraging range of the species.

  19. Galactose-Deficient IgA1 as a Candidate Urinary Polypeptide Marker of IgA Nephropathy?

    PubMed

    Suzuki, Hitoshi; Allegri, Landino; Suzuki, Yusuke; Hall, Stacy; Moldoveanu, Zina; Wyatt, Robert J; Novak, Jan; Julian, Bruce A

    2016-01-01

    In patients with IgA nephropathy (IgAN), circulatory IgA1 and IgA1 in mesangial deposits contain elevated amounts of galactose-deficient IgA1 (Gd-IgA1). We hypothesized that a fraction of Gd-IgA1 from the glomerular deposits and/or circulation may be excreted into the urine and thus represent a disease-specific biomarker. Levels of urinary IgA and Gd-IgA1 were determined in 207 patients with IgAN, 205 patients with other renal diseases, and 57 healthy controls, recruited in USA, Japan, and Italy. Urinary IgA was similarly elevated in patients with IgAN and renal-disease controls compared with healthy controls. However, urinary Gd-IgA1 levels were higher in patients with IgAN (IgAN, 28.0 ± 17.9; disease controls, 20.6 ± 17.4 units/mg urinary creatinine; P < 0.0001). Lectin western blotting data confirmed these results. In IgAN patients, levels of urinary Gd-IgA1 correlated with proteinuria (P < 0.001). When we purified IgA from serum and urine of an IgAN patient, the relative proportion of Gd-IgA1 to total IgA1 was higher in the urine compared with serum, suggesting selective excretion of Gd-IgA1 in IgAN. In summary, urinary excretion of Gd-IgA1 was elevated in patients with IgAN and the urinary Gd-IgA1 levels correlated with proteinuria. Urinary Gd-IgA1 may thus represent a disease-specific biomarker of IgAN.

  20. Galactose-Deficient IgA1 as a Candidate Urinary Polypeptide Marker of IgA Nephropathy?

    PubMed Central

    Allegri, Landino; Hall, Stacy; Wyatt, Robert J.

    2016-01-01

    In patients with IgA nephropathy (IgAN), circulatory IgA1 and IgA1 in mesangial deposits contain elevated amounts of galactose-deficient IgA1 (Gd-IgA1). We hypothesized that a fraction of Gd-IgA1 from the glomerular deposits and/or circulation may be excreted into the urine and thus represent a disease-specific biomarker. Levels of urinary IgA and Gd-IgA1 were determined in 207 patients with IgAN, 205 patients with other renal diseases, and 57 healthy controls, recruited in USA, Japan, and Italy. Urinary IgA was similarly elevated in patients with IgAN and renal-disease controls compared with healthy controls. However, urinary Gd-IgA1 levels were higher in patients with IgAN (IgAN, 28.0 ± 17.9; disease controls, 20.6 ± 17.4 units/mg urinary creatinine; P < 0.0001). Lectin western blotting data confirmed these results. In IgAN patients, levels of urinary Gd-IgA1 correlated with proteinuria (P < 0.001). When we purified IgA from serum and urine of an IgAN patient, the relative proportion of Gd-IgA1 to total IgA1 was higher in the urine compared with serum, suggesting selective excretion of Gd-IgA1 in IgAN. In summary, urinary excretion of Gd-IgA1 was elevated in patients with IgAN and the urinary Gd-IgA1 levels correlated with proteinuria. Urinary Gd-IgA1 may thus represent a disease-specific biomarker of IgAN. PMID:27647947

  1. Bacterial IgA protease-mediated degradation of agIgA1 and agIgA1 immune complexes as a potential therapy for IgA Nephropathy.

    PubMed

    Wang, Li; Li, Xueying; Shen, Hongchun; Mao, Nan; Wang, Honglian; Cui, Luke; Cheng, Yuan; Fan, Junming

    2016-08-03

    Mesangial deposition of aberrantly glycosylated IgA1 (agIgA1) and its immune complexes is a key pathogenic mechanism of IgA nephropathy (IgAN). However, treatment of IgAN remains ineffective. We report here that bacteria-derived IgA proteases are capable of degrading these pathogenic agIgA1 and derived immune complexes in vitro and in vivo. By screening 14 different bacterial strains (6 species), we found that 4 bacterial IgA proteases from H. influenzae, N. gonorrhoeae and N. meningitidis exhibited high cleaving activities on serum agIgA1 and artificial galactose-depleted IgA1 in vitro and the deposited agIgA1-containing immune complexes in the mesangium of renal biopsy from IgAN patients and in a passive mouse model of IgAN in vitro. In the modified mouse model of passive IgAN with abundant in situ mesangial deposition of the agIgA-IgG immune complexes, a single intravenous delivery of IgA protease from H. influenzae was able to effectively degrade the deposited agIgA-IgG immune complexes within the glomerulus, demonstrating a therapeutic potential for IgAN. In conclusion, the bacteria-derived IgA proteases are biologically active enzymes capable of cleaving the circulating agIgA and the deposited agIgA-IgG immune complexes within the kidney of IgAN. Thus, the use of such IgA proteases may represent a novel therapy for IgAN.

  2. Bacterial IgA protease-mediated degradation of agIgA1 and agIgA1 immune complexes as a potential therapy for IgA Nephropathy

    PubMed Central

    Wang, Li; Li, Xueying; Shen, Hongchun; Mao, Nan; Wang, Honglian; Cui, Luke; Cheng, Yuan; Fan, Junming

    2016-01-01

    Mesangial deposition of aberrantly glycosylated IgA1 (agIgA1) and its immune complexes is a key pathogenic mechanism of IgA nephropathy (IgAN). However, treatment of IgAN remains ineffective. We report here that bacteria-derived IgA proteases are capable of degrading these pathogenic agIgA1 and derived immune complexes in vitro and in vivo. By screening 14 different bacterial strains (6 species), we found that 4 bacterial IgA proteases from H. influenzae, N. gonorrhoeae and N. meningitidis exhibited high cleaving activities on serum agIgA1 and artificial galactose-depleted IgA1 in vitro and the deposited agIgA1-containing immune complexes in the mesangium of renal biopsy from IgAN patients and in a passive mouse model of IgAN in vitro. In the modified mouse model of passive IgAN with abundant in situ mesangial deposition of the agIgA-IgG immune complexes, a single intravenous delivery of IgA protease from H. influenzae was able to effectively degrade the deposited agIgA-IgG immune complexes within the glomerulus, demonstrating a therapeutic potential for IgAN. In conclusion, the bacteria-derived IgA proteases are biologically active enzymes capable of cleaving the circulating agIgA and the deposited agIgA-IgG immune complexes within the kidney of IgAN. Thus, the use of such IgA proteases may represent a novel therapy for IgAN. PMID:27485391

  3. How ecology shapes prey fish cognition.

    PubMed

    Beri, S; Patton, B W; Braithwaite, V A

    2014-11-01

    Fish exhibit diverse cognitive capacities: they cooperate, punish, develop cultural traditions, learn to map their environment and communicate their intentions to one another. Skills such as these have helped fish radiate to colonize the many and diverse aquatic niches available. Prey fish are no exception to this, and several recent studies have shown them to be a rich resource for understanding the evolutionary ecology of animal cognition. Many fish have to cope with the threat of predation, but some environments contain more predators than others. These environments deliver the opportunity to investigate how predation pressure shapes fish cognition and behaviour. Here we compared fish from two high and two low predation habitats in their ability to learn a sequential choice spatial task. We also investigated their ability to solve the maze after it was rearranged. Fish from high predation sites made more errors as they learned to navigate the maze than fish from low predation sites. The fish also varied in the cues that they learned to help them solve the task. These did not vary by levels of predation pressure, rather, they differed between rivers, with fish from one river learning to use landmark cues, and those from the other river learning the sequence of left and right turns. As the different populations varied in how well they learned to navigate through a reconfigured maze, it seems likely that predation pressure is not the only factor influencing spatial behavior in these fish.

  4. Functional Differences between IgM and IgD Signaling in Chronic Lymphocytic Leukemia.

    PubMed

    Ten Hacken, Elisa; Sivina, Mariela; Kim, Ekaterina; O'Brien, Susan; Wierda, William G; Ferrajoli, Alessandra; Estrov, Zeev; Keating, Michael J; Oellerich, Thomas; Scielzo, Cristina; Ghia, Paolo; Caligaris-Cappio, Federico; Burger, Jan A

    2016-09-15

    BCR signaling is a central pathogenetic pathway in chronic lymphocytic leukemia (CLL). Most CLL cells express BCRs of IgM and IgD isotypes, but the contribution of these isotypes to functional responses remains incompletely defined. We therefore investigated differences between IgM and IgD signaling in freshly isolated peripheral blood CLL cells and in CLL cells cultured with nurselike cells, a model that mimics the lymph node microenvironment. IgM signaling induced prolonged activation of ERK kinases and promoted CLL cell survival, CCL3 and CCL4 chemokine secretion, and downregulation of BCL6, the transcriptional repressor of CCL3 In contrast, IgD signaling induced activation of the cytoskeletal protein HS1, along with F-actin polymerization, which resulted in rapid receptor internalization and failure to support downstream responses, including CLL cell survival and chemokine secretion. IgM and IgD receptor downmodulation, HS1 and ERK activation, chemokine secretion, and BCL6 downregulation were also observed when CLL cells were cocultured with nurselike cells. The Bruton's tyrosine kinase inhibitor ibrutinib effectively inhibited both IgM and IgD isotype signaling. In conclusion, through a variety of functional readouts, we demonstrate very distinct outcomes of IgM and IgD isotype activation in CLL cells, providing novel insight into the regulation of BCR signaling in CLL.

  5. IgA nephropathy in Brazil: apropos of 600 cases.

    PubMed

    Soares, Maria Fernanda; Caldas, M L R; Dos-Santos, W L C; Sementilli, A; Furtado, P; Araújo, S; Pegas, K L; Petterle, R R; Franco, M F

    2015-01-01

    IgA nephropathy (IgAN) is th e commonest primary glomerular disease worldwide. Studies on its prevalence in Brazil are however scarce. Databases and clinical records from 10 reference centres were retrospectively reviewed. Clinical and laboratory features at the moment of the biopsy were retrieved (age, gender, presence of hematuria, serum creatinine [mg/dL], proteinuria [g/24 h]). Renal biopsy findings were classified according to Haas single grade classification scheme and the Oxford Classification of IgAN. 600 cases of IgAN were identified, of which 568 (94.7 %) were on native kidneys. Male to female ratio was 1.24:1. Patients averaged 32.76 ± 15.12 years old (range 4-89, median 32). Proteinuria and hematuria were observed, respectively in 56.63 and 72.29 % of patients. The association of both these findings occurred in 37.95 % of the cases. Serum creatinine averaged 1.65 ± 0.67 mg/dL (median 1.5 mg/dL) at diagnosis. Segmental sclerosis and mesangial hypercellularity were the main glomerular findings (47.6 and 46.2 %) The commonest combination by Oxford Classification of IgAN, was M0 E0 S0 T0 (22.4 %). Chronic tubulo-interstitial lesions with an extension wider than 25 % of the renal cortex could be identified in 32.2 % of the cases. Tubular atrophy and interstitial fibrosis were more strongly associated with higher 24-h proteinuria and serum creatinine levels. Segmental sclerosis (S1) showed a stronger tendency of association with the presence of tubulo-interstitial lesions (T1 and T2) than other glomerular variables. To the best of our knowledge this is the largest series of IgAN in Brazil. It depicts the main biopsy findings and their possible clinical correlates. Our set of data is comparable to previous reports.

  6. Predator dispersal determines the effect of connectivity on prey diversity.

    PubMed

    Limberger, Romana; Wickham, Stephen A

    2011-01-01

    Linking local communities to a metacommunity can positively affect diversity by enabling immigration of dispersal-limited species and maintenance of sink populations. However, connectivity can also negatively affect diversity by allowing the spread of strong competitors or predators. In a microcosm experiment with five ciliate species as prey and a copepod as an efficient generalist predator, we analysed the effect of connectivity on prey species richness in metacommunities that were either unconnected, connected for the prey, or connected for both prey and predator. Presence and absence of predator dispersal was cross-classified with low and high connectivity. The effect of connectivity on local and regional richness strongly depended on whether corridors were open for the predator. Local richness was initially positively affected by connectivity through rescue of species from stochastic extinctions. With predator dispersal, however, this positive effect soon turned negative as the predator spread over the metacommunity. Regional richness was unaffected by connectivity when local communities were connected only for the prey, while predator dispersal resulted in a pronounced decrease of regional richness. The level of connectivity influenced the speed of richness decline, with regional species extinctions being delayed for one week in weakly connected metacommunities. While connectivity enabled rescue of prey species from stochastic extinctions, deterministic extinctions due to predation were not overcome through reimmigration from predator-free refuges. Prey reimmigrating into these sink habitats appeared to be directly converted into increased predator abundance. Connectivity thus had a positive effect on the predator, even when the predator was not dispersing itself. Our study illustrates that dispersal of a species with strong negative effects on other community members shapes the dispersal-diversity relationship. When connections enable the spread of a

  7. Red queen dynamics in specific predator-prey systems.

    PubMed

    Harris, Terence; Cai, Anna Q

    2015-10-01

    The dynamics of a predator-prey system are studied, with a comparison of discrete and continuous strategy spaces. For a [Formula: see text] system, the average strategies used in the discrete and continuous case are shown to be the same. It is further shown that the inclusion of constant prey switching in the discrete case can have a stabilising effect and reduce the number of available predator types through extinction.

  8. Predator Dispersal Determines the Effect of Connectivity on Prey Diversity

    PubMed Central

    Limberger, Romana; Wickham, Stephen A.

    2011-01-01

    Linking local communities to a metacommunity can positively affect diversity by enabling immigration of dispersal-limited species and maintenance of sink populations. However, connectivity can also negatively affect diversity by allowing the spread of strong competitors or predators. In a microcosm experiment with five ciliate species as prey and a copepod as an efficient generalist predator, we analysed the effect of connectivity on prey species richness in metacommunities that were either unconnected, connected for the prey, or connected for both prey and predator. Presence and absence of predator dispersal was cross-classified with low and high connectivity. The effect of connectivity on local and regional richness strongly depended on whether corridors were open for the predator. Local richness was initially positively affected by connectivity through rescue of species from stochastic extinctions. With predator dispersal, however, this positive effect soon turned negative as the predator spread over the metacommunity. Regional richness was unaffected by connectivity when local communities were connected only for the prey, while predator dispersal resulted in a pronounced decrease of regional richness. The level of connectivity influenced the speed of richness decline, with regional species extinctions being delayed for one week in weakly connected metacommunities. While connectivity enabled rescue of prey species from stochastic extinctions, deterministic extinctions due to predation were not overcome through reimmigration from predator-free refuges. Prey reimmigrating into these sink habitats appeared to be directly converted into increased predator abundance. Connectivity thus had a positive effect on the predator, even when the predator was not dispersing itself. Our study illustrates that dispersal of a species with strong negative effects on other community members shapes the dispersal-diversity relationship. When connections enable the spread of a

  9. Local Bifurcations and Optimal Theory in a Delayed Predator-Prey Model with Threshold Prey Harvesting

    NASA Astrophysics Data System (ADS)

    Tankam, Israel; Tchinda Mouofo, Plaire; Mendy, Abdoulaye; Lam, Mountaga; Tewa, Jean Jules; Bowong, Samuel

    2015-06-01

    We investigate the effects of time delay and piecewise-linear threshold policy harvesting for a delayed predator-prey model. It is the first time that Holling response function of type III and the present threshold policy harvesting are associated with time delay. The trajectories of our delayed system are bounded; the stability of each equilibrium is analyzed with and without delay; there are local bifurcations as saddle-node bifurcation and Hopf bifurcation; optimal harvesting is also investigated. Numerical simulations are provided in order to illustrate each result.

  10. Integrated pest management with stochastic birth rate for prey species

    PubMed Central

    Akman, Olcay; Comar, Timothy D.; Hrozencik, Daniel

    2013-01-01

    Song and Xiang (2006) developed an impulsive differential equations model for a two-prey one-predator model with stage structure for the predator. They demonstrate the conditions on the impulsive period for which a globally asymptotically stable pest-eradication periodic solution exists, as well as conditions on the impulsive period for which the prey species is permanently maintained under an economically acceptable threshold. We extend their model by including stage structure for both predator and prey as well as by adding stochastic elements in the birth rate of the prey. As in Song and Xiang (2006), we find the conditions under which a globally asymptotically stable pest eradication periodic solution exists. In addition, we numerically show the relationship between the stochastically varying birth rate of the prey and the necessary efficacy of the pesticide for which the probability of eradication of the prey species is above 90%. This is significant because the model recognizes varying environmental and climatic conditions which affect the resources needed for pest eradication. PMID:23964194

  11. The impact of environmental toxins on predator-prey dynamics.

    PubMed

    Huang, Qihua; Wang, Hao; Lewis, Mark A

    2015-08-07

    Predators and prey may be simultaneously exposed to environmental toxins, but one may be more susceptible than the other. To study the effects of environmental toxins on food web dynamics, we develop a toxin-dependent predator-prey model that combines both direct and indirect toxic effects on two trophic levels. The direct effects of toxins typically reduce organism abundance by increasing mortality or reducing fecundity. Such direct effects, therefore, alter both bottom-up food availability and top-down predatory ability. However, the indirect effects, when mediated through predator-prey interactions, may lead to counterintuitive effects. This study investigates how the balance of the classical predator-prey dynamics changes as a function of environmental toxin levels. While high toxin concentrations are shown to be harmful to both species, possibly leading to extirpation of both species, intermediate toxin concentrations may affect predators disproportionately through biomagnification, leading to reduced abundance of predators and increased abundance of the prey. This counterintuitive effect significantly increases biomass at the lower trophic level. Environmental toxins may also reduce population variability by preventing populations from fluctuating around a coexistence equilibrium. Finally, environmental toxins may induce bistable dynamics, in which different initial population levels produce different long-term outcomes. Since our toxin-dependent predator-prey model is general, the theory developed here not only provides a sound foundation for population or community effects of toxicity, but also could be used to help develop management strategies to preserve and restore the integrity of contaminated habitats.

  12. Dynamics of Predator-Prey Metapopulations with Allee Effects.

    PubMed

    Fan, Meng; Wu, Ping; Feng, Zhilan; Swihart, Robert K

    2016-08-01

    Allee effects increasingly are recognized as influential determinants of population dynamics, especially in disturbed landscapes. We developed a predator-prey metapopulation model to study the impact of an Allee effect on predator-prey. The model incorporates habitat destruction and predators with imperfect information about prey distribution. Criteria are established for the existence and stability of equilibria, and the possible existence of a limit cycle is discussed. Numerical bifurcation analysis of the model is carried out to examine the impact of Allee effects as well as other key processes on trophic dynamics. Inclusion of Allee effects produces a richer array of dynamics than earlier models in which it was absent. When prey interacts with generalist predators, Allee effects operate synergistically to depress prey populations. Allee effects are more likely to depress occupancy levels when destruction of habitat patches is moderate; at severe levels of destruction, Allee effects are swamped by demographic effects of habitat loss. Stronger Allee effects correspond to lower thresholds of predator colonization rates at which prey become extinct. We discuss implications of our model for conservation of rare species as well as pest management via biocontrol.

  13. Indirect evolutionary rescue: prey adapts, predator avoids extinction.

    PubMed

    Yamamichi, Masato; Miner, Brooks E

    2015-09-01

    Recent studies have increasingly recognized evolutionary rescue (adaptive evolution that prevents extinction following environmental change) as an important process in evolutionary biology and conservation science. Researchers have concentrated on single species living in isolation, but populations in nature exist within communities of interacting species, so evolutionary rescue should also be investigated in a multispecies context. We argue that the persistence or extinction of a focal species can be determined solely by evolutionary change in an interacting species. We demonstrate that prey adaptive evolution can prevent predator extinction in two-species predator-prey models, and we derive the conditions under which this indirect evolutionary interaction is essential to prevent extinction following environmental change. A nonevolving predator can be rescued from extinction by adaptive evolution of its prey due to a trade-off for the prey between defense against predation and population growth rate. As prey typically have larger populations and shorter generations than their predators, prey evolution can be rapid and have profound effects on predator population dynamics. We suggest that this process, which we term 'indirect evolutionary rescue', has the potential to be critically important to the ecological and evolutionary responses of populations and communities to dramatic environmental change.

  14. Predator interference and stability of predator-prey dynamics.

    PubMed

    Přibylová, Lenka; Berec, Luděk

    2015-08-01

    Predator interference, that is, a decline in the per predator consumption rate as predator density increases, is generally thought to promote predator-prey stability. Indeed, this has been demonstrated in many theoretical studies on predator-prey dynamics. In virtually all of these studies, the stabilization role is demonstrated as a weakening of the paradox of enrichment. With predator interference, stable limit cycles that appear as a result of environmental enrichment occur for higher values of the environmental carrying capacity of prey, and even a complete absence of the limit cycles can happen. Here we study predator-prey dynamics using the Rosenzweig-MacArthur-like model in which the Holling type II functional response has been replaced by a predator-dependent family which generalizes many of the commonly used descriptions of predator interference. By means of a bifurcation analysis we show that sufficiently strong predator interference may bring about another stabilizing mechanism. In particular, hysteresis combined with (dis)appearance of stable limit cycles imply abrupt increases in both the prey and predator densities and enhanced persistence and resilience of the predator-prey system. We encourage refitting the previously collected data on predator consumption rates as well as for conducting further predation experiments to see what functional response from the explored family is the most appropriate.

  15. Caste evolution and ecology: a special worker for novel prey

    PubMed Central

    Powell, Scott; Franks, Nigel R

    2005-01-01

    Individual specialization underpins the division of labour within ant societies, but only in a small minority do morphological specialists, or physical castes, exist in the workforce. The genetic conditions that allow such castes to evolve are well understood, but the ecological pressures that select for them are not. We provide compelling evidence that the task of transporting novel prey selected for an exaggerated transport caste, or ‘submajor’, in the army ant Eciton burchellii. This species is the only Eciton that preys upon large arthropods as well as ants, the ancestral prey type, and by comparing load-transport among Eciton species and within E. burchellii, we show that this mixed diet significantly constrains transport efficiency. Crucially, however, we also show that E. burchellii submajors are highly specialized on transporting non-ant prey, and we demonstrate experientially that it is specifically this prey type that constrains prey-transport efficiency. Our study also suggests that phylogenetic constraints associated with the Eciton lifestyle intensified selection for the exaggerated submajor of E. burchellii. Thus, we propose that a novel task may only select for a special caste when phylogenetic constraints preclude the evolution of alternative solutions. This identifies a new and potentially general scenario for the evolution of physical castes. PMID:16188606

  16. Integrated pest management with stochastic birth rate for prey species.

    PubMed

    Akman, Olcay; Comar, Timothy D; Hrozencik, Daniel

    2013-01-01

    Song and Xiang (2006) developed an impulsive differential equations model for a two-prey one-predator model with stage structure for the predator. They demonstrate the conditions on the impulsive period for which a globally asymptotically stable pest-eradication periodic solution exists, as well as conditions on the impulsive period for which the prey species is permanently maintained under an economically acceptable threshold. We extend their model by including stage structure for both predator and prey as well as by adding stochastic elements in the birth rate of the prey. As in Song and Xiang (2006), we find the conditions under which a globally asymptotically stable pest eradication periodic solution exists. In addition, we numerically show the relationship between the stochastically varying birth rate of the prey and the necessary efficacy of the pesticide for which the probability of eradication of the prey species is above 90%. This is significant because the model recognizes varying environmental and climatic conditions which affect the resources needed for pest eradication.

  17. Role of IgA receptors in the pathogenesis of IgA nephropathy.

    PubMed

    Lechner, Sebastian M; Papista, Christina; Chemouny, Jonathan M; Berthelot, Laureline; Monteiro, Renato C

    2016-02-01

    Immunoglobulin A nephropathy (IgAN) or Berger's disease is the most common form of primary glomerulonephritis in the world and one of the first causes of end-stage renal failure. IgAN is characterized by the accumulation of immune complexes containing polymeric IgA1 in mesangial areas. The pathogenesis of this disease involves the deposition of polymeric and hypogalactosylated IgA1 (Gd-IgA1) in the mesangium. Quantitative and structural changes of Gd-IgA1 play a key role in the development of the disease due to functional abnormalities of two IgA receptors: the FcαRI (CD89) expressed by blood myeloid cells and the transferrin receptor (CD71) on mesangial cells. Abnormal Gd-IgA1 induces release of soluble CD89, which participates in the formation of circulating IgA1 complexes. These complexes are trapped by CD71 that is overexpressed on mesangial cells in IgAN patients together with the crosslinking enzyme transglutaminase 2 allowing pathogenic IgA complex formation in situ and mesangial cell activation. A humanized mouse model expressing IgA1 and CD89 develops IgAN in a similar manner as patients. In this model, a food antigen, the gliadin, was shown to be crucial for circulating IgA1 complex formation and deposition, which could be prevented by a gluten-free diet. Identification of these new partners opens new therapeutic prospects for IgAN treatment.

  18. The Mast Cell-IgE Paradox

    PubMed Central

    Galli, Stephen J.

    2017-01-01

    Mast cells and IgE are so inextricably linked to the pathology of allergic disorders, including fatal anaphylaxis, that it can be difficult to think of them in other contexts. Surely, we do not have mast cells and IgE so that we can eat a peanut and die! It is thought that mast cells and IgE and basophils (circulating granulocytes, whose functions partially overlap with those of mast cells) can contribute to host defense as components of adaptive T helper cell type 2 immune responses to helminths, ticks, and certain other parasites. Accordingly, it was suggested that allergies are misdirected type 2 immune responses in which IgE antibodies are produced against any of a broad variety of apparently harmless antigens. However, components of animal venoms also can sensitize individuals to develop severe IgE-associated allergic reactions, including fatal anaphylaxis, on subsequent venom exposure. Here, I describe evidence that mast cells can enhance innate host resistance to reptile or arthropod venoms during responses to an initial exposure to such venoms and that acquired type 2 immune responses, IgE antibodies, the high-affinity IgE receptor FcεRI, and mast cells can contribute toward acquired resistance in mice to the lethal effects of honeybee or Russell's viper venom. These findings support the hypothesis that mast cells and IgE can help protect the host against noxious substances. PMID:26776074

  19. [Clinical symptoms in IgA deficiency].

    PubMed

    De Oliveira-Serra, Flavio Augusto; Mosca, Tainá; Santos de Menezes, Maria da Conceição; Carvalho-Neves Forte, Wilma

    2017-01-01

    Antecedentes: La deficiencia de inmunoglobulina A (IgA) es la inmunodeficiencia primaria más frecuente. El diagnóstico oportuno y el seguimiento clínico pueden mejorar la calidad de vida de los portadores. Para ello, deben estudiarse y entenderse las manifestaciones clínicas de este trastorno. Objetivo: Determinar las manifestaciones clínicas de la deficiencia de IgA. Métodos: Estudio transversal, retrospectivo, exploratorio, realizado mediante análisis de expedientes de 39 pacientes con deficiencia de IgA. Resultados: De los pacientes analizados, 10 fueron diagnosticados con deficiencia total de IgA y 29 con deficiencia parcial. Las principales manifestaciones clínicas fueron rinoconjuntivitis y asma alérgicas. En los pacientes con deficiencia total de IgA, además de las enfermedades alérgicas se observó un mayor número de cuadros infecciosos de rinosinusitis, amigdalitis y conjuntivitis (p < 0.05). Conclusión: En el presente estudio, las principales manifestaciones clínicas de la deficiencia de IgA fueron los cuadros alérgicos de rinoconjuntivitis y el asma; además, los pacientes portadores de deficiencia total de IgA presentaron aumento significativo de cuadros infecciosos de rinosinusitis, amigdalitis y conjuntivitis, comparados con los pacientes con deficiencia parcial de IgA.

  20. IgA Antibodies in Rett Syndrome

    ERIC Educational Resources Information Center

    Reichelt, K. L.; Skjeldal, O.

    2006-01-01

    The level of IgA antibodies to gluten and gliadin proteins found in grains and to casein found in milk, as well as the level of IgG to gluten and gliadin, have been examined in 23 girls with Rett syndrome and 53 controls. Highly statistically significant increases were found for the Rett population compared to the controls. The reason for this…

  1. Female sexuality.

    PubMed

    Rao, T S Sathyanarana; Nagaraj, Anil Kumar M

    2015-07-01

    Sex is a motive force bringing a man and a woman into intimate contact. Sexuality is a central aspect of being human throughout life and encompasses sex, gender identities and roles, sexual orientation, eroticism, pleasure, intimacy, and reproduction. Sexuality is experienced and expressed in thoughts, fantasies, desires, beliefs, attitudes, values, behaviors, practices, roles and relationships. Though generally, women are sexually active during adolescence, they reach their peak orgasmic frequency in their 30 s, and have a constant level of sexual capacity up to the age of 55 with little evidence that aging affects it in later life. Desire, arousal, and orgasm are the three principle stages of the sexual response cycle. Each stage is associated with unique physiological changes. Females are commonly affected by various disorders in relation to this sexual response cycle. The prevalence is generally as high as 35-40%. There are a wide range of etiological factors like age, relationship with a partner, psychiatric and medical disorders, psychotropic and other medication. Counseling to overcome stigma and enhance awareness on sexuality is an essential step in management. There are several effective psychological and pharmacological therapeutic approaches to treat female sexual disorders. This article is a review of female sexuality.

  2. Female sexuality

    PubMed Central

    Rao, T.S. Sathyanarana; Nagaraj, Anil Kumar M.

    2015-01-01

    Sex is a motive force bringing a man and a woman into intimate contact. Sexuality is a central aspect of being human throughout life and encompasses sex, gender identities and roles, sexual orientation, eroticism, pleasure, intimacy, and reproduction. Sexuality is experienced and expressed in thoughts, fantasies, desires, beliefs, attitudes, values, behaviors, practices, roles and relationships. Though generally, women are sexually active during adolescence, they reach their peak orgasmic frequency in their 30 s, and have a constant level of sexual capacity up to the age of 55 with little evidence that aging affects it in later life. Desire, arousal, and orgasm are the three principle stages of the sexual response cycle. Each stage is associated with unique physiological changes. Females are commonly affected by various disorders in relation to this sexual response cycle. The prevalence is generally as high as 35–40%. There are a wide range of etiological factors like age, relationship with a partner, psychiatric and medical disorders, psychotropic and other medication. Counseling to overcome stigma and enhance awareness on sexuality is an essential step in management. There are several effective psychological and pharmacological therapeutic approaches to treat female sexual disorders. This article is a review of female sexuality. PMID:26330647

  3. IgM, IgA and IgG producing cells in cerebrospinal fluid and peripheral blood in multiple sclerosis.

    PubMed Central

    Henriksson, A; Kam-Hansen, S; Link, H

    1985-01-01

    The protein A plaque assay was used to enumerate IgM, IgA and IgG producing cells per 20 X 10(3) lymphocytes in cerebrospinal fluid (CSF) and peripheral blood (PB) from 37 patients with multiple sclerosis (MS) and in PB from healthy controls. Fifty-seven percent of the MS patients displayed in CSF cells producing IgM, 70% IgA and 89% IgG. IgM or IgA producing cells predominated in CSF from 10 patients, IgG in 27. Immunoglobulin producing cells were often present when the corresponding CSF Ig index was normal, confirming that enumeration of Ig producing cells is a more sensitive variable of the intrathecal immune status. No Ig producing cells were found in CSF from four patients with tension headache, indicating absence of intrathecal Ig synthesis in healthy individuals. The patients with MS had higher numbers of IgM, IgA and IgG producing cells in PB than healthy controls, confirming occurrence of an extrathecal B cell response in MS. Active and stable MS patients did not differ regarding Ig producing cells in CSF nor in PB, which speaks in favour of continuous immune activity within as well as outside the CNS independent of clinical symptoms. PMID:4064372

  4. Identification of Prey Captures in Australian Fur Seals (Arctocephalus pusillus doriferus) Using Head-Mounted Accelerometers: Field Validation with Animal-Borne Video Cameras

    PubMed Central

    Volpov, Beth L.; Hoskins, Andrew J.; Battaile, Brian C.; Viviant, Morgane; Wheatley, Kathryn E.; Marshall, Greg; Abernathy, Kyler; Arnould, John P. Y.

    2015-01-01

    This study investigated prey captures in free-ranging adult female Australian fur seals (Arctocephalus pusillus doriferus) using head-mounted 3-axis accelerometers and animal-borne video cameras. Acceleration data was used to identify individual attempted prey captures (APC), and video data were used to independently verify APC and prey types. Results demonstrated that head-mounted accelerometers could detect individual APC but were unable to distinguish among prey types (fish, cephalopod, stingray) or between successful captures and unsuccessful capture attempts. Mean detection rate (true positive rate) on individual animals in the testing subset ranged from 67-100%, and mean detection on the testing subset averaged across 4 animals ranged from 82-97%. Mean False positive (FP) rate ranged from 15-67% individually in the testing subset, and 26-59% averaged across 4 animals. Surge and sway had significantly greater detection rates, but also conversely greater FP rates compared to heave. Video data also indicated that some head movements recorded by the accelerometers were unrelated to APC and that a peak in acceleration variance did not always equate to an individual prey item. The results of the present study indicate that head-mounted accelerometers provide a complementary tool for investigating foraging behaviour in pinnipeds, but that detection and FP correction factors need to be applied for reliable field application. PMID:26107647

  5. Prey abundance and food habits of San Joaquin kit fox (Vulpes velox macrotis) at Camp Roberts Army National Guard Training site, California

    SciTech Connect

    Logan, C.G.; Berry, W.H.; Standley, W.G.; Kato, T.T.

    1992-09-01

    Prey abundance and food habits of the San Joaquin kit fox (Vulpes velox macrotis) were investigated at Camp Roberts Army National Guard Training site, California, from November 1988 through September 1991. The sampling methods initially used to assess abundance of prey species resulted in indices too low to be of value. Because of this, the relationship between relative abundance and frequency of occurrence of prey species could not be examined. Six hundred forty-nine fecal samples (scats) were analyzed to determine the frequency of occurrence of prey items. California ground squirrels (Spermophilus beecheyi) and lagomorphs primarily desert cottontails (Sylvilagus audubonii) and black-tailed jackrabbits (Lepus californicus) were the most frequently occurring mammalian prey items found in scats (35.0% and 12.2%, respectively). The frequency of occurrence of ground squirrel (but not lagomorph) remains in scats collected from juveniles was significantly higher than in scats collected from adults. The frequency of occurrence of ground squirrel and lagomorph remains in scats collected from males was not significant different than in scats collected from females. There were significant variations in the frequency of ground squirrel remains among the years 1989--1991 and during the June--November periods between 1989 and 1990 and between 1990 and 1991. The frequency of lagomorph remains collected during the June--November period differed significantly among the years 1989--1991 and between 1990 and 1991.

  6. Identification of Prey Captures in Australian Fur Seals (Arctocephalus pusillus doriferus) Using Head-Mounted Accelerometers: Field Validation with Animal-Borne Video Cameras.

    PubMed

    Volpov, Beth L; Hoskins, Andrew J; Battaile, Brian C; Viviant, Morgane; Wheatley, Kathryn E; Marshall, Greg; Abernathy, Kyler; Arnould, John P Y

    2015-01-01

    This study investigated prey captures in free-ranging adult female Australian fur seals (Arctocephalus pusillus doriferus) using head-mounted 3-axis accelerometers and animal-borne video cameras. Acceleration data was used to identify individual attempted prey captures (APC), and video data were used to independently verify APC and prey types. Results demonstrated that head-mounted accelerometers could detect individual APC but were unable to distinguish among prey types (fish, cephalopod, stingray) or between successful captures and unsuccessful capture attempts. Mean detection rate (true positive rate) on individual animals in the testing subset ranged from 67-100%, and mean detection on the testing subset averaged across 4 animals ranged from 82-97%. Mean False positive (FP) rate ranged from 15-67% individually in the testing subset, and 26-59% averaged across 4 animals. Surge and sway had significantly greater detection rates, but also conversely greater FP rates compared to heave. Video data also indicated that some head movements recorded by the accelerometers were unrelated to APC and that a peak in acceleration variance did not always equate to an individual prey item. The results of the present study indicate that head-mounted accelerometers provide a complementary tool for investigating foraging behaviour in pinnipeds, but that detection and FP correction factors need to be applied for reliable field application.

  7. Reciprocity in predator-prey interactions: exposure to defended prey and predation risk affects intermediate predator life history and morphology.

    PubMed

    Hammill, Edd; Beckerman, Andrew P

    2010-05-01

    A vast body of literature exists documenting the morphological, behavioural and life history changes that predators induce in prey. However, little attention has been paid to how these induced changes feed back and affect the predators' life history and morphology. Larvae of the phantom midge Chaoborus flavicans are intermediate predators in a food web with Daphnia pulex as the basal resource and planktivorous fish as the top predator. C. flavicans prey on D. pulex and are themselves prey for fish; as D. pulex induce morphological defences in the presence of C. flavicans this is an ideal system in which to evaluate the effects of defended prey and top predators on an intermediate consumer. We assessed the impact on C. flavicans life history and morphology of foraging on defended prey while also being exposed to the non-lethal presence of a top fish predator. We tested the basic hypothesis that the effects of defended prey will depend on the presence or absence of top predator predation risk. Feeding rate was significantly reduced and time to pupation was significantly increased by defended morph prey. Gut size, development time, fecundity, egg size and reproductive effort respond to fish chemical cues directly or significantly alter the relationship between a trait and body size. We found no significant interactions between prey morph and the non-lethal presence of a top predator, suggesting that the effects of these two biological factors were additive or singularly independent. Overall it appears that C. flavicans is able to substantially modify several aspects of its biology, and while some changes appear mere consequences of resource limitation others appear facultative in nature.

  8. Dynamics and patterns of a diffusive Leslie-Gower prey-predator model with strong Allee effect in prey

    NASA Astrophysics Data System (ADS)

    Ni, Wenjie; Wang, Mingxin

    2016-10-01

    This paper is devoted to study the dynamical properties and stationary patterns of a diffusive Leslie-Gower prey-predator model with strong Allee effect in the prey population. We first analyze the nonnegative constant equilibrium solutions and their stabilities, and then study the dynamical properties of time-dependent solutions. Moreover, we investigate the stationary patterns induced by diffusions (Turing pattern). Our results show that the impact of the strong Allee effect essentially increases the system spatiotemporal complexity.

  9. Comparing nearshore benthic and pelagic prey as mercury sources to lake fish: the importance of prey quality and mercury content.

    PubMed

    Karimi, Roxanne; Chen, Celia Y; Folt, Carol L

    2016-09-15

    Mercury (Hg) bioaccumulation in fish poses well-known health risks to wildlife and humans through fish consumption. Yet fish Hg concentrations are highly variable, and key factors driving this variability remain unclear. One little studied source of variation is the influence of habitat-specific feeding on Hg accumulation in lake fish. However, this is likely important because most lake fish feed in multiple habitats during their lives, and the Hg and caloric content of prey from different habitats can differ. This study used a three-pronged approach to investigate the extent to which habitat-specific prey determine differences in Hg bioaccumulation in fish. This study first compared Hg concentrations in common nearshore benthic invertebrates and pelagic zooplankton across five lakes and over the summer season in one lake, and found that pelagic zooplankton generally had higher Hg concentrations than most benthic taxa across lakes, and over a season in one lake. Second, using a bioenergetics model, the effects of prey caloric content from habitat-specific diets on fish growth and Hg accumulation were calculated. This model predicted that the consumption of benthic prey results in lower fish Hg concentrations due to higher prey caloric content and growth dilution (high weight gain relative to Hg from food), in addition to lower prey Hg levels. Third, using data from the literature, links between fish Hg content and the degree of benthivory, were examined, and showed that benthivory was associated with reduced Hg concentrations in lake fish. Taken together, these findings support the hypothesis that higher Hg content and lower caloric content make pelagic zooplankton prey greater sources of Hg for fish than nearshore benthic prey in lakes. Hence, habitat-specific foraging is likely to be a strong driver of variation in Hg levels within and between fish species.

  10. Complications of IgA nephropathy in a non-insulin-dependent diabetes model, the Akita mouse.

    PubMed

    Haseyama, Toshiyuki; Fujita, Toshiki; Hirasawa, Fujiko; Tsukada, Mikako; Wakui, Hideki; Komatsuda, Atsushi; Ohtani, Hiroshi; Miura, Akira B; Imai, Hirokazu; Koizumi, Akio

    2002-12-01

    The Akita mouse, which has a mutation (Cys96Tyr) in the insulin 2 gene (Ins2(Akita)), is a model for diabetes. The male Akita mouse has diabetes, while females develop mild diabetes. This study aimed to investigate renal complications in the Akita mouse model, which has been maintained in a heterozygous state Ins2(Akita) (+/-) with a C57BL/6 background (B6). Renal function (BUN, creatinine), serum IgA concentrations and histological changes in the kidneys were evaluated in diabetic and control mice in a B6 background. Five each of male and female mice per group (diabetes vs. control) were killed at 10, 20, 30 and 40 weeks of age. The influence of major histocompatibility antigens (MHC) on renal complications was tested using male diabetic mice in a C3H/He (C3H) background. When compared with controls, diabetic males, but not females, developed impaired renal function with elevation of serum IgA after 30 weeks of age. Diabetic glomerulosclerosis advanced with age in both sexes. Diffuse granular mesangial deposits of IgA were detected by immunofluorescence microscopy in diabetic males after 20 weeks. We tested whether the IgA-associated lesions were influenced by MHC using diabetic males in a C3H background. Similar degrees of diabetic glomerulosclerosis and glomerular IgA deposition were found in mice with C3H and B6 backgrounds. Akita mouse is a unique mouse model showing both mesangial sclerosis and IgA nephropathy.

  11. Zebrafish immunoglobulin IgD: unusual exon usage and quantitative expression profiles with IgM and IgZ/T heavy chain isotypes.

    PubMed

    Zimmerman, Anastasia M; Moustafa, Farah M; Romanowski, Kryzstof E; Steiner, Lisa A

    2011-09-01

    The zebrafish is an emerging model for comparative immunology and biomedical research. In contrast to the five heavy chain isotype system of mice and human (IgD, IgM, IgA, IgG, IgE), zebrafish harbor gene segments for IgD, IgM, and novel heavy chain isotype called IgZ/T which appears restricted to bony fishes. The purpose of this study was to design and validate a suite of quantitative real time RT-PCR protocols to measure IgH expression in a vertebrate model which has considerable promise for modeling both pathogenic infection and chronic conditions leading to immune dysfunction. Specific primers were designed and following verification of their specificty, relative expression levels of IgD, IgM, and IgZ/T were measured in triplicate for zebrafish raised under standard laboratory conditions. During embryonic stages, low levels of each heavy chain isotype (IgH) were detected with each increasing steadily between 2 and 17 weeks post fertilization. Overall IgM>IgZ>IgD throughout zebrafish development with the copy number of IgM being several fold higher than that of IgD or IgZ/T. IgD exon usage was also characterized, as its extremely long size and presence of a stop codon in the second IgD exon in zebrafish, raised questions as to how this antibody might be expressed. Zebrafish IgD was found to be a chimeric immunoglobulin, with the third IgD exon spliced to the first IgM constant exon thereby circumventing the first and second IgD exons. Collectively, the qRT-PCR results represent the first comparative profile of IgD, IgM, IgZ/T expression over the lifespan of any fish species and the primers and assay parameters reported should prove useful in enabling researchers to rapidly quantify changes in IgH expression in zebrafish models of disease where altered IgH expression is manifested.

  12. The clinical condition of IgA-deficient patients is related to the proportion of IgD- and IgM-producing cells in their nasal mucosa.

    PubMed Central

    Brandtzaeg, P; Karlsson, G; Hansson, G; Petruson, B; Björkander, J; Hanson, L A

    1987-01-01

    Nasal biopsy specimens from 15 adult patients with selective IgA deficiency but normal IgG-subclass levels were examined by immunohistochemistry for the presence of immunocytes producing various Ig isotypes. The mucosal samples were completely IgA-deficient except in two cases where 0.9% and 8.4% IgA cells were found, respectively (normal, 69.8%). Numerous IgG- (mainly IgG1-) producing cells were present in 10 samples; in five of these there were additional IgM- but virtually no IgD-producing cells, whereas in the other five a marked dominance of the IgD over the IgM isotype was seen. The latter category of patients had more upper airways infections (recurrent acute rhinosinusitis, otitis media, and tonsillitis) than the former, who had no recurrent upper respiratory tract infections except one patient with recurrent acute rhinosinusitis. The five remaining samples, which contained very few Ig-producing cells, were derived from patients with even more frequent infections than those showing IgD predominance. Our results indicate that IgM acts as a compensatory secretory Ig in the upper respiratory tract of some IgA-deficient subjects. However, immunoregulatory events favouring local IgD responses apparently do not support mucosal defence satisfactorily, either because local production of IgM is hampered or because IgD (which is not a secretory Ig) blocks complement-dependent reactions mediated by IgG and IgM antibodies within the mucosa. Images Fig. 2 PMID:3301101

  13. Variable prey development time suppresses predator-prey cycles and enhances stability.

    PubMed

    Cronin, James T; Reeve, John D; Xu, Dashun; Xiao, Mingqing; Stevens, Heidi N

    2016-03-01

    Although theoretical models have demonstrated that predator-prey population dynamics can depend critically on age (stage) structure and the duration and variability in development times of different life stages, experimental support for this theory is non-existent. We conducted an experiment with a host-parasitoid system to test the prediction that increased variability in the development time of the vulnerable host stage can promote interaction stability. Host-parasitoid microcosms were subjected to two treatments: Normal and High variance in the duration of the vulnerable host stage. In control and Normal-variance microcosms, hosts and parasitoids exhibited distinct population cycles. In contrast, insect abundances were 18-24% less variable in High- than Normal-variance microcosms. More significantly, periodicity in host-parasitoid population dynamics disappeared in the High-variance microcosms. Simulation models confirmed that stability in High-variance microcosms was sufficient to prevent extinction. We conclude that developmental variability is critical to predator-prey population dynamics and could be exploited in pest-management programs.

  14. Predators choose prey over prey habitats: evidence from a lynx-hare system.

    PubMed

    Keim, Jonah L; DeWitt, Philip D; Lele, Subhash R

    2011-06-01

    Resource selection is grounded in the understanding that animals select resources based on fitness requirements. Despite uncertainty in how mechanisms relate to the landscape, resource selection studies often assume, but rarely demonstrate, a relationship between modeled variables and fitness mechanisms. Using Canada lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) as a model system, we assess whether prey habitat is a viable surrogate for encounters between predators and prey. We simultaneously collected winter track data for lynx and hare in two study areas. We used information criteria to determine whether selection by lynx is best characterized by a hare resource selection probability function (RSPF) or by the amount of hare resource use. Results show that lynx selection is better explained by the amount of hare use (SIC = -21.9; Schwarz's Information Criterion) than by hare RSPF (SIC = -16.71), and that hare RSPF cannot be assumed to reveal the amount of resource use, a primary mechanism of predator selection. Our study reveals an obvious but important distinction between selection and use that is applicable to all resource selection studies. We recommend that resource selection studies be coupled with mechanistic data (e.g., metrics of diet, forage, fitness, or abundance) when investigating mechanisms of resource selection.

  15. Enhancement of anti-OVA IgG2c production in vivo by enalapril.

    PubMed

    Almeida, L C; Muraro, L S; Albuquerque, D A

    2016-07-11

    Angiotensin-converting enzyme (ACE) inhibitors have non-hemodynamic, pleiotropic effects on the immune response. The effects of ACE inhibitors on the production of cytokines and T-cell functions are well established. However, little is known on the effects of these medicines on humoral response to foreign antigens. In this study, we investigated the effect of enalapril treatment on ovalbumin (OVA)-specific IgG1 and IgG2c production in mice determined by ELISA. Two groups of 8-week-old C57BL/6 females mice (3-4/group) were subcutaneously immunized with OVA (10 μg/animal) in presence of Alhydrogel (1 mg/mouse) and boosted at day 21. The mice were treated with enalapril (5 mg/kg daily, po) or were left without treatment for one month. The animals were bled from the orbital plexus on days 0, 7, 14, 21, and 28 after the first immunization and the sera were stored at -20°C until usage. OVA-specific serum IgG1 and IgG2c were determined by ELISA using serum from each individual animal. The results showed that enalapril significantly increased anti-OVA serum IgG2c in the secondary response without affecting IgG1 synthesis. These data expand our understanding on the properties of enalapril on the immune response, including antibody production.

  16. Mesangial IgA deposits indicate pathogenesis of anti-glomerular basement membrane disease.

    PubMed

    Wang, Aifeng; Wang, Yongping; Wang, Guobao; Zhou, Zhanmei; Xun, Zhang; Tan, Xiaohui

    2012-05-01

    Anti-glomerular basement membrane (anti-GBM) disease is characterized by crescentic glomerulonephritis with immunoglobulin G (IgG) autoantibodies to the non-collagenous (NC1) domain of α3(IV) collagen presenting along the GBM. The patient clinically manifests with rapidly progressive glomerulonephritis (RPGN) with pulmonary hemorrhage (Goodpasture syndrome). In rare cases, other immunocomplexes of IgA or IgM are involved, but their specificities have not been determined. We report a rare case of a 31-year-old female who was diagnosed as having anti-GBM disease with extensive IgA deposits in the mesangium. This patient presented heavy hematuria, proteinuria with increasing creatinine, but no lung hemorrhage. Renal biopsy showed crescentic glomerulonephritis (type Ⅰ) with strong IgA (3+) as lump and branch shape. Therapies with pulse methylprednisolone, plasmapheresis and cyclophosphamide administration were less effective. This case is different from the present type Ⅰ crescentic glomerulonephritis and the specificity of IgA deposits may implicate the pathogenesis of anti-GBM disease.

  17. [Salmonella typhi vaccination response study reveals defective antibody production selective IgA deficiency patient].

    PubMed

    Pleguezuelo, Daniel E; Gianelli, Carla

    2015-01-01

    Selective IgA deficiency (SIgAD) is the most prevalent immunodeficiency worldwide, progressing to common variable immunodeficiency only in few reported cases. We report the case of a Spanish female aged 22 and diagnosed of selective IgA deficiency, a long history of bronchitis, several episodes of pneumonia, bilateral bronchiectasis, normal IgG, IgM, IgG subclasses, and detectable pre-vaccination IgG antibodies against tetanus toxoid and Streptococcus pneumoniae. She was evaluated in our clinic in order to rule out common variable immunodeficiency. We observed good antibody response to tetanus toxoid, absence of circulating switched memory B cells, decreased response to pneumococcal polysaccharide antigens and a lack of response to Salmonella typhi vaccine. Most SIgAD patients presents with upper respiratory tract infections or mild diarrhea. Those with lower tract infections, pneumonia or untreatable diarrhea should follow B-cell subpopulations' study and antibody response to vaccines. Absence of response to Salmonella typhi vaccine allowed us to expose the defective antibody production.

  18. Enhancement of anti-OVA IgG2c production in vivo by enalapril

    PubMed Central

    Almeida, L.C.; Muraro, L.S.; Albuquerque, D.A.

    2016-01-01

    Angiotensin-converting enzyme (ACE) inhibitors have non-hemodynamic, pleiotropic effects on the immune response. The effects of ACE inhibitors on the production of cytokines and T-cell functions are well established. However, little is known on the effects of these medicines on humoral response to foreign antigens. In this study, we investigated the effect of enalapril treatment on ovalbumin (OVA)-specific IgG1 and IgG2c production in mice determined by ELISA. Two groups of 8-week-old C57BL/6 females mice (3–4/group) were subcutaneously immunized with OVA (10 μg/animal) in presence of Alhydrogel (1 mg/mouse) and boosted at day 21. The mice were treated with enalapril (5 mg/kg daily, po) or were left without treatment for one month. The animals were bled from the orbital plexus on days 0, 7, 14, 21, and 28 after the first immunization and the sera were stored at –20°C until usage. OVA-specific serum IgG1 and IgG2c were determined by ELISA using serum from each individual animal. The results showed that enalapril significantly increased anti-OVA serum IgG2c in the secondary response without affecting IgG1 synthesis. These data expand our understanding on the properties of enalapril on the immune response, including antibody production. PMID:27409332

  19. An Overlapping Case of Lupus Nephritis and IgG4-Related Kidney Disease.

    PubMed

    Zaarour, Mazen; Weerasinghe, Chanudi; Eter, Ahmad; El-Sayegh, Suzanne; El-Charabaty, Elie

    2015-07-01

    We report a case of a 71-year-old Filipino female who was admitted to the hospital for abdominal pain, vomiting and diarrhea of 8 days duration. The patient was found to have marked acute kidney injury (AKI), which required hemodialysis in the next 3 days. Extensive workup revealed hematuria, subnephrotic range proteinuria, elevated anti-nuclear antibody (ANA) and elevated total immunoglobulin G (IgG) levels, with normal IgG4 and anti-dsDNA levels. On kidney biopsy, mild membranous glomerulonephritis was found, along with autoimmune tubulointerstitial nephritis (TIN) with a "full-house" pattern of immune deposits. These findings were suggestive of lupus interstitial nephritis. However, IgG4+ plasma cells were detected in the interstitium by immunostaining, favoring a diagnosis of IgG4-related kidney disease (IgG4-RKD). Our case highlights the difficulty in differentiating lupus nephritis (LN) from IgG4-RKD in some patients, raising the suspicion that these two entities can co-exist.

  20. An Overlapping Case of Lupus Nephritis and IgG4-Related Kidney Disease

    PubMed Central

    Zaarour, Mazen; Weerasinghe, Chanudi; Eter, Ahmad; El-Sayegh, Suzanne; El-Charabaty, Elie

    2015-01-01

    We report a case of a 71-year-old Filipino female who was admitted to the hospital for abdominal pain, vomiting and diarrhea of 8 days duration. The patient was found to have marked acute kidney injury (AKI), which required hemodialysis in the next 3 days. Extensive workup revealed hematuria, subnephrotic range proteinuria, elevated anti-nuclear antibody (ANA) and elevated total immunoglobulin G (IgG) levels, with normal IgG4 and anti-dsDNA levels. On kidney biopsy, mild membranous glomerulonephritis was found, along with autoimmune tubulointerstitial nephritis (TIN) with a “full-house” pattern of immune deposits. These findings were suggestive of lupus interstitial nephritis. However, IgG4+ plasma cells were detected in the interstitium by immunostaining, favoring a diagnosis of IgG4-related kidney disease (IgG4-RKD). Our case highlights the difficulty in differentiating lupus nephritis (LN) from IgG4-RKD in some patients, raising the suspicion that these two entities can co-exist. PMID:26015827

  1. Effect of dispersal in two-patch prey-predator system with positive density dependence growth of preys.

    PubMed

    Sasmal, Sourav Kumar; Ghosh, Dibakar

    2017-01-01

    Prey-predator systems in patchy environment, connected through dispersal between patches is a very common phenomenon observed in nature, which have a significant impact in ecology, species persistence and extinction, etc. In the present paper, we consider a two patch prey-predator system where the patches are connected through dispersal between preys populations only. We consider positive density dependence growth for preys population. In addition, we consider the time scale difference (different life span) between preys and predator populations. From our study, we can conclude that dispersal can save both the populations from extinction, when in a single patch initial preys density is lower the Allee threshold. Also, time difference can increase the basin of attraction of the coexistence equilibrium of our two-patch model. Time scale difference also can help to reach the steady state faster than the without time scale difference, and it also causes the amplitude death when populations are in limit cycle oscillation. We also analyze our model by considering the time delay in dispersal dynamics, and we show that delay induced dispersal can stabilize the system and cause the amplitude death when individual populations are in the limit cycle, without dispersal. In addition, dispersal in non-identical patches can stabilize at its interior equilibrium even if the environment is harsh for both the populations in both the individual patches.

  2. Interrupting peptidoglycan deacetylation during Bdellovibrio predator-prey interaction prevents ultimate destruction of prey wall, liberating bacterial-ghosts

    PubMed Central

    Lambert, Carey; Lerner, Thomas R.; Bui, Nhat Khai; Somers, Hannah; Aizawa, Shin-Ichi; Liddell, Susan; Clark, Ana; Vollmer, Waldemar; Lovering, Andrew L.; Sockett, R. Elizabeth

    2016-01-01

    The peptidoglycan wall, located in the periplasm between the inner and outer membranes of the cell envelope in Gram-negative bacteria, maintains cell shape and endows osmotic robustness. Predatory Bdellovibrio bacteria invade the periplasm of other bacterial prey cells, usually crossing the peptidoglycan layer, forming transient structures called bdelloplasts within which the predators replicate. Prey peptidoglycan remains intact for several hours, but is modified and then degraded by escaping predators. Here we show predation is altered by deleting two Bdellovibrio N-acetylglucosamine (GlcNAc) deacetylases, one of which we show to have a unique two domain structure with a novel regulatory”plug”. Deleting the deacetylases limits peptidoglycan degradation and rounded prey cell “ghosts” persist after mutant-predator exit. Mutant predators can replicate unusually in the periplasmic region between the peptidoglycan wall and the outer membrane rather than between wall and inner-membrane, yet still obtain nutrients from the prey cytoplasm. Deleting two further genes encoding DacB/PBP4 family proteins, known to decrosslink and round prey peptidoglycan, results in a quadruple mutant Bdellovibrio which leaves prey-shaped ghosts upon predation. The resultant bacterial ghosts contain cytoplasmic membrane within bacteria-shaped peptidoglycan surrounded by outer membrane material which could have promise as “bacterial skeletons” for housing artificial chromosomes. PMID:27211869

  3. Tonsillectomy and IgA nephritis.

    PubMed

    Ponticelli, Claudio

    2012-07-01

    IgA nephritis (IgAN) is an autoimmune disease characterized by deposits of IgA in the glomerular mesangium. Clinically, the disease may be punctuated by episodes of macroscopic haematuria often associated with pharingotonsillitis or may be oligosyntomatic with microscopic haematuria and mild proteinuria. The natural course of IgAN may be indolent and benign; however, some 30-50% of patients may progress to end-stage renal disease when follow-up is extended to ≥20 years. In patients with IgAN, circulating IgA1 molecules have an aberrant structure of O-glycans in the hinge region, which is characterized by abbreviated glycans composed of N-acetylgalactosamine, with or without sialic acid. These aberrant IgA1 trigger the production of autoantibodies, with formation of immune complexes that deposit in the mesangium causing inflammation and production of extracellular matrix. A number of experimental and clinical data outlined a possible pathogenetic role of tonsillitis. As a consequence, tonsillectomy has been frequently performed in Japan. Observational studies, made in patients with normal renal function and mild proteinuria, reported that tonsillectomy could reduce the episodes of macrohaematuria as well as the entity of microhaematuria and proteinuria. However, the available studies had short-term follow-up and could not asses the role of tonsillectomy in protecting from renal function deterioration. In a longitudinal retrospective study, Isseki et al. compared the outcome of tonsillectomized patients with IgAN with that of IgAN patients who did not receive tonsillectomy. Tonsillectomized patients had a higher number of remissions and a better slope of glomerular filtration rate in comparison with controls. These data are interesting and suggest that tonsillectomy may prevent renal dysfunction in patients with IgAN and normal renal function. However, the retrospective nature of the study and the presence of some confounding factors require further investigations

  4. IgG4-related spinal pachymeningitis.

    PubMed

    Lu, Zhang; Tongxi, Liu; Jie, Luo; Yujuan, Jiao; Wei, Jiang; Xia, Liu; Yumin, Zheng; Xin, Lu

    2016-06-01

    The aim of this study is to study the clinical, laboratory, imaging pathology, and prognosis features of IgG4-related spinal pachymeningitis. We worked with a 55-year-old man suffering from IgG4-related spinal pachymeningitis who had the most widespread lesion in his dura mater. We also review previous related studies and discuss the clinical characteristics of this rare disease. In total, eight IgG4-related spinal pachymeningitis patients have been reported in the literature since 2009. They were mostly male patients, 51.7 ± 11.9 years old on average. Cervical and thoracic vertebrae were the most common sites for lesions. The most prominent symptom was varying numbness and weakness of the limbs and/or body associated with spinal cord compression. There was one patient (1/5) with elevated serum IgG4 levels and three patients (3/3) with increased cerebrospinal fluid (CSF) IgG4 index. Positive histopathologic findings are the strongest basis for a diagnosis. All the patients with IgG4-related spinal pachymeningitis responded well to glucocorticoid therapy. IgG4-related spinal pachymeningitis is an orphan disease that mainly occurs in cervical and thoracic vertebrae. Older males are the most susceptible group. Serum IgG4 levels were consistently normal in these cases, so analysis of CSF for IgG4 production (IgG4 index) could become a useful tool. Pathological findings remain the gold standard for diagnosis. Most patients responded favorably to glucocorticoid treatment.

  5. Inflammation in IgA nephropathy.

    PubMed

    Rauen, Thomas; Floege, Jürgen

    2017-03-14

    Immunoglobulin A nephropathy (IgAN) is the most frequently occurring primary glomerulonephritis in Caucasian and Asian populations. Nonetheless, therapeutic recommendations are based on weak evidence, large controlled trials are scarce and, in particular, the additional value of immunosuppression beyond comprehensive supportive measures is not well-established. The use of immunosuppressants is supported by experimental insights into IgAN pathogenesis that suggest an autoimmune component in disease development. The so-called "multi-hit" theory comprises multiple steps, starting with defective glycosylation of IgA subclass IgA1 that results in overproduction of galactose-deficient IgA1 (Gd-IgA1), occurrence of anti-Gd-IgA1 autoantibodies, and mesangial deposition of nephritogenic immune complexes. This eventually results in an increased mesangial cell proliferation, inflammatory responses, and complement activation. Recent genome-wide association studies have identified several susceptibility genes, many of which support the "multi-hit" concept. In light of these discoveries, it is astonishing that the vast majority of adult IgAN patients obviously do not need and/or benefit from immunosuppressive therapies in the first place. In fact, a number of supportive measures are highly effective in reducing the risk for disease progression in many patients. These measures need to be optimized before immunosuppression should be considered at all. In this review we focus on the underlying pathogenetic cornerstones and the central question of whether systemic inflammation in adult IgAN patients should be treated. Treatment options in children with IgAN are also discussed.

  6. IgA-antigliadin antibodies in IgA mesangial nephropathy (Berger's disease).

    PubMed

    Fornasieri, A; Sinico, R A; Maldifassi, P; Bernasconi, P; Vegni, M; D'Amico, G

    1987-07-11

    Circulating IgA-antigliadin antibodies were detected with enzyme linked immunosorbent assay (ELISA) in four of 121 patients (3%) who had IgA mesangial nephropathy and 14 of 17 children (82%) who had untreated coeliac disease. No positive cases were present in the 54 healthy subjects of the control group. Three patients who had IgA nephropathy and IgA-antigliadin antibodies underwent jejunal biopsy, and two showed mucosal atrophy. In these two patients urinary abnormalities, together with the IgA-antigliadin antibodies, disappeared completely after three months and five months, respectively, of following a gluten free diet. Circulating IgA immune complexes were found in most patients who had coeliac disease and Berger's disease associated with IgA-antigliadin antibodies, suggesting overactivity of the B cells producing IgA in both conditions. By contrast, a circulating IgA rheumatoid factor was detectable in three of the four patients who had IgA nephropathy and asymptomatic coeliac disease but was always absent in children who had coeliac disease but did not show signs of renal disease. These results suggest that a more complex abnormality in the IgA immune response is necessary for renal disease to become manifest in patients who have gluten enteropathy.

  7. Amphibians have immunoglobulins similar to ancestral IgD and IgA from Amniotes.

    PubMed

    Estevez, Olivia; Garet, Elina; Olivieri, David; Gambón-Deza, Francisco

    2016-01-01

    We studied the immunoglobulin genes from either the genomes or RNAs of amphibians. In particular, we obtained data from one frog genome (Nanorana parkeri) and three transcriptomes of the Caudata order (Andrias davidianus, Notophthalmus viridescens and Cynops pyrrhogaster). Apart from the immunoglobulins IgM and IgY previously described, we identified several IgD related immunoglobulins. The species N. parkeri, N. viridescens and C. pyrrhogaster have two IgD genes, while Andrias davidianus has three such genes. The three Caudata species have long IgD immunoglobulins similar to IgD of reptiles, and could be an ancient relic from the common ancestor of IgD of all mammals and reptiles. We also found two IgA isotypes. The results suggest that one of the IgA may be the ancestor of IgA in crocodiles and birds, while the other could be the ancestor IgA found in mammals. These results provide information that could help understand the evolution of immunoglobulins in terrestrial vertebrates.

  8. Neuromuscular control of prey capture in frogs.

    PubMed Central

    Nishikawa, K C

    1999-01-01

    While retaining a feeding apparatus that is surprisingly conservative morphologically, frogs as a group exhibit great variability in the biomechanics of tongue protraction during prey capture, which in turn is related to differences in neuromuscular control. In this paper, I address the following three questions. (1) How do frog tongues differ biomechanically? (2) What anatomical and physiological differences are responsible? (3) How is biomechanics related to mechanisms of neuromuscular control? Frog species use three non-exclusive mechanisms to protract their tongues during feeding: (i) mechanical pulling, in which the tongue shortens as its muscles contract during protraction; (ii) inertial elongation, in which the tongue lengthens under inertial and muscular loading; and (iii) hydrostatic elongation, in which the tongue lengthens under constraints imposed by the constant volume of a muscular hydrostat. Major differences among these functional types include (i) the amount and orientation of collagen fibres associated with the tongue muscles and the mechanical properties that this connective tissue confers to the tongue as a whole; and (ii) the transfer of intertia from the opening jaws to the tongue, which probably involves a catch mechanism that increases the acceleration achieved during mouth opening. The mechanisms of tongue protraction differ in the types of neural mechanisms that are used to control tongue movements, particularly in the relative importance of feed-forward versus feedback control, in requirements for precise interjoint coordination, in the size and number of motor units, and in the afferent pathways that are involved in coordinating tongue and jaw movements. Evolution of biomechanics and neuromuscular control of frog tongues provides an example in which neuromuscular control is finely tuned to the biomechanical constraints and opportunities provided by differences in morphological design among species. PMID:10382226

  9. Do lions Panthera leo actively select prey or do prey preferences simply reflect chance responses via evolutionary adaptations to optimal foraging?

    PubMed

    Hayward, Matt W; Hayward, Gina J; Tambling, Craig J; Kerley, Graham I H

    2011-01-01

    Research on coursing predators has revealed that actions throughout the predatory behavioral sequence (using encounter rate, hunting rate, and kill rate as proxy measures of decisions) drive observed prey preferences. We tested whether similar actions drive the observed prey preferences of a stalking predator, the African lion Panthera leo. We conducted two 96 hour, continuous follows of lions in Addo Elephant National Park seasonally from December 2003 until November 2005 (16 follows), and compared prey encounter rate with prey abundance, hunt rate with prey encounter rate, and kill rate with prey hunt rate for the major prey species in Addo using Jacobs' electivity index. We found that lions encountered preferred prey species far more frequently than expected based on their abundance, and they hunted these species more frequently than expected based on this higher encounter rate. Lions responded variably to non-preferred and avoided prey species throughout the predatory sequence, although they hunted avoided prey far less frequently than expected based on the number of encounters of them. We conclude that actions of lions throughout the predatory behavioural sequence, but particularly early on, drive the prey preferences that have been documented for this species. Once a hunt is initiated, evolutionary adaptations to the predator-prey interactions drive hunting success.

  10. Intraguild interactions among three spider mite predators: predation preference and effects on juvenile development and oviposition.

    PubMed

    Rahmani, Hasan; Daneshmandi, Aliakbar; Walzer, Andreas

    2015-12-01

    A first step to evaluate potential negative effects of intraguild predation (IGP) when using multiple predators against a pest species is the determination of the predation behavior of the predators and the nutritional value of intraguild (IG) prey in terms of development and oviposition. Here, we investigated the predation preference of the female predatory mites Neoseiulus californicus, Typhlodromus bagdasarjani and Phytoseius plumifer, when having choice between larvae of the two other predatory mite species (IG prey) with and without extraguild prey, the spider mite Tetranychus urticae (EG prey). Additionally, we evaluated the juvenile development and oviposition of the three predator species when provided with larvae from each other species. Irrespective of EG prey, IG prey species affected neither the first attack nor attack times of the three female IG predator species. The IG predation rates of the predator females, however, were influenced by prey species in the absence of EG prey. Neoseiulus californicus females killed more P. plumifer than T. bagdasarjani larvae, whereas T. bagdasarjani and P. plumifer females killed more N. californicus than P. plumifer and T. bagdasarjani larvae, respectively. All IG predator species consumed significantly more EG than IG prey. IG prey species did not influence juvenile and adult survival probabilities of the IG predators. We conclude that IGP is a weak force among the three predators and the potential consequences of IGP should not result in the elimination of one by another tested predatory mite species at least in the presence of spider mites.

  11. [IgG(4)-related disease involving the trachea and paratracheal soft tissue: a case report and literature review].

    PubMed

    Fang, W L; Wang, H J; Lu, Y W; Feng, R E; Bu, X N; Fang, Q H

    2017-03-01

    Objective: To investigate the clinical data of a patient with IgG(4)-related disease involving the trachea and paratracheal soft tissue and review the literature so as to improve the understanding level of the disorder. Methods: To analyze the clinical manifestation, laboratory examination, imaging, histopathology, treatment and prognosis of a patient with IgG(4)-related disease trachea and paratracheal soft tissue involved, who was admitted to the Department of Respiratory and Critical Care Medicine at Beijing Chaoyang Hospital. The relevant literatures were reviewed. Results: A 18-year-old female was admitted with chief complaint of cough, dyspnea, and neck mass. Neck CT suggested that tracheal stenosis was caused by surrounded soft tissue. Paratracheal mass biopsy showed dense collagen fibers with infiltration of many lymphocytes and plasma cells. Immunohistochemical stain found that IgG(4)-positive plasma cells were >50/high power field (HPF) and a ratio of IgG(4)/IgG positive cells was over 40% .The level of serum IgG(4) was significantly increased (2 930 mg/L). She was diagnosed as IgG(4)-related disease. The patient was treated with 80 mg intravenous methylprednisolone per day for three days, then prednisone 40 mg daily oral. Her dyspnea was significantly relieved.One month later, CT scan showed that the cervical tracheal stenosis was significantly improved. We identified 20 cases of IgG(4)-related disease involving the trachea and paratracheal soft tissue from databases, in which only 1 case was similar as this patient. The other 19 cases were of extratracheal involvement. Elevated serum IgG(4) was detected in 11/12 patients. Most patients were treated with glucocorticoid, some combined with immunosuppressive agents and rituximab. The clinical outcome was good. Conclusion: IgG(4)-related disease involving the trachea and paratracheal soft tissue is a rare condition. Serum IgG(4) level and histopathology should be considered for diagnosis. Glucocorticoid is

  12. Concomitant occurrence of IgG4-related pleuritis and periaortitis: a case report with review of the literature.

    PubMed

    Ishida, Mitsuaki; Hodohara, Keiko; Furuya, Aya; Fujishiro, Aya; Okuno, Hiroko; Yoshii, Miyuki; Horinouchi, Akiko; Shirakawa, Ayaka; Harada, Ayumi; Iwai, Muneo; Yoshida, Keiko; Kagotani, Akiko; Yoshida, Takashi; Okabe, Hidetoshi

    2014-01-01

    IgG4-related sclerosing disease is an established disease entity with characteristic clinicopathological features. Some recent reports have demonstrated that this disease can occur in the respiratory system including the pleura. Herein, we describe the first documented case of concomitant occurrence of IgG4-related pleuritis and periaortitis. A 71-year-old Japanese female with a history of essential thrombocythemia presented with persistent cough and difficulty in breathing. Computed tomography demonstrated thickening of the right parietal pleura, pericardium, and periaortic tissue and pleural and cardiac effusions. Histopathological study of the surgical biopsy specimen of the parietal pleura revealed marked fibrous thickening with lymphoplasmacytic infiltration. Phlebitis was noted, however, only a few eosinophils had infiltrated. Immunohistochemical study revealed abundant IgG4-positive plasma cell infiltration and high ratio of IgG4-/IgG-positive plasma cells (84%). Therefore, a diagnosis of IgG4-related pleuritis was made with consideration of the elevated serum IgG4 level (684 mg/dL). Recently, the spectrum of IgG4-related sclerosing disease has expanded, and this disease can occur in the pleura, pericardium, and periaortic tissue. Although histopathological analysis of the pericardium and periaortic tissue was not performed in the present case, it was suspected that thickening of the pericardium and periaortic tissue was clinically due to IgG4-related sclerosing disease. Our clinicopathological analyses of IgG4-related pleuritis and pericarditis reveal that this disease can present as dyspnea and pleural and pericardial effusion as seen in the present case, therefore, it is important to recognize that IgG4-related sclerosing disease can occur in these organs for accurate diagnosis and treatment.

  13. Prey capture in frogs: alternative strategies, biomechanical trade-offs, and hierarchical decision making.

    PubMed

    Monroy, Jenna A; Nishikawa, Kiisa

    2011-02-01

    Frogs exhibit flexible repertoires of prey-capture behavior, which depend primarily on visual analysis of prey attributes. We review three examples of how visual cues are used to modulate prey-capture strategies. (1) Dyscophus guineti modulates tongue aiming in response to prey location. These frogs turn only their heads to apprehend prey located at azimuths <40°. At azimuths >40°, the frogs switch from this strategy to one in which both head and tongue are aimed toward prey. (2) Rana pipiens modulates its feeding behavior in response to prey size, using tongue prehension for capturing small prey but switching to jaw prehension to capture large prey. (3) In Cyclorana novaehollandiae, visual processing of prey attributes involves hierarchical decision making. These frogs first assess prey size. For large prey, they ignore velocity but not shape. For small prey, they ignore shape but not velocity. Alternative prey-capture strategies are associated with biomechanical trade-offs that result from the interaction between the feeding apparatus and varying attributes of prey. Alternative strategies likely exist because biomechanical constraints prevent any one strategy from being effective over a range of prey attributes. Taken together, these studies emphasize the requirement that predators must somehow tune prey-capture kinematics simultaneously to multiple attributes of prey. In frogs, the choice among alternative prey-capture strategies involves a hierarchical decision-making process. Hierarchical decision making is expected to be widespread among animals. However, no previous studies were found except for humans, who frequently use this type of approach to make complex decisions.

  14. Impacts of human disturbance on large prey species: do behavioral reactions translate to fitness consequences?

    PubMed

    Leblond, Mathieu; Dussault, Christian; Ouellet, Jean-Pierre

    2013-01-01

    Anthropogenic disturbances have been demonstrated to affect animal behavior, distribution, and abundance, but assessment of their impacts on fitness-related traits has received little attention. We hypothesized that human activities and infrastructure cause a decrease in the individual performance of preys because of anthropogenically enhanced predation risk. We evaluated the impacts of commercial logging and road networks on the fitness of a large herbivore known to be sensitive to human disturbance: the forest-dwelling woodland caribou (Rangifer tarandus caribou). For 8 consecutive years (2004-2011) we monitored 59 individuals using GPS telemetry in the Charlevoix region of Québec, Canada. We also used Very High Frequency telemetry locations collected on 28 individuals from 1999-2000. We related habitat selection of adult caribou at various spatio-temporal scales to their probability of dying from predation, and to indices of their reproductive success and energy expenditure. The probability that adult caribou died from predation increased with the proportion of recent disturbances (including cutblocks ≤ 5 years old) in their annual home range. The respective effects of increasing paved and forestry road densities depended upon the overall road density within the home range of caribou. At a finer scale of 10 to 15 days before their death, caribou that were killed by a predator selected for recent disturbances more than individuals that survived, and avoided old mature conifer stands. The home range area of caribou increased with road density. Finally, the composition of the home range of females had no effect on their reproductive success. We show that human activities and infrastructure may influence the individual performance of large prey species in highly managed regions. We outline the need to consider the full set of impacts that human development may have on threatened animal populations, with particular emphasis on predator-prey relationships and

  15. Impacts of Human Disturbance on Large Prey Species: Do Behavioral Reactions Translate to Fitness Consequences?

    PubMed Central

    Leblond, Mathieu; Dussault, Christian; Ouellet, Jean-Pierre

    2013-01-01

    Anthropogenic disturbances have been demonstrated to affect animal behavior, distribution, and abundance, but assessment of their impacts on fitness-related traits has received little attention. We hypothesized that human activities and infrastructure cause a decrease in the individual performance of preys because of anthropogenically enhanced predation risk. We evaluated the impacts of commercial logging and road networks on the fitness of a large herbivore known to be sensitive to human disturbance: the forest-dwelling woodland caribou (Rangifer tarandus caribou). For 8 consecutive years (2004–2011) we monitored 59 individuals using GPS telemetry in the Charlevoix region of Québec, Canada. We also used Very High Frequency telemetry locations collected on 28 individuals from 1999–2000. We related habitat selection of adult caribou at various spatio-temporal scales to their probability of dying from predation, and to indices of their reproductive success and energy expenditure. The probability that adult caribou died from predation increased with the proportion of recent disturbances (including cutblocks ≤5 years old) in their annual home range. The respective effects of increasing paved and forestry road densities depended upon the overall road density within the home range of caribou. At a finer scale of 10 to 15 days before their death, caribou that were killed by a predator selected for recent disturbances more than individuals that survived, and avoided old mature conifer stands. The home range area of caribou increased with road density. Finally, the composition of the home range of females had no effect on their reproductive success. We show that human activities and infrastructure may influence the individual performance of large prey species in highly managed regions. We outline the need to consider the full set of impacts that human development may have on threatened animal populations, with particular emphasis on predator-prey relationships and

  16. Serum galactose-deficient IgA1 levels in children with IgA nephropathy.

    PubMed

    Jiang, Mengjie; Jiang, Xiaoyun; Rong, Liping; Xu, Yuanyuan; Chen, Lizhi; Qiu, Zeting; Mo, Ying

    2015-01-01

    Immunoglobulin A nephropathy (IgAN) is an immunopathologic diagnosis based on a renal biopsy, it is characterized by deposits of IgA-containing immune complexes in the mesangium. Adults with IgAN have a galactose-deficient IgA1 in the circulation and glomerular deposition. There are few studies on the glycosylation of serum IgA1 in children with IgAN. To measure the serum levels of galactose-deficient IgA1 in pediatric patients with IgAN, 72 biopsy-proven IgAN children were divided into 3 groups based on the clinical features: isolated hematuria group (24 patients), hematuria and proteinuria group (22 patients), and nephritic syndrome group (26 patients). They were also divided into 3 groups according to pathologic grading: grade I + II group (25 patients), grade III group (33 patients) and grade IV + V group (14 patients). 30 healthy children were recruited as a control group. We used vicia villosa lectin binding enzyme-linked immunosorbent assay to measure the serum levels of galactose-deficient IgA1 in all groups and controls. Serum levels of galactose-deficient IgA1 in children with IgAN were higher than controls (P < 0.01). There were no significant differences in serum levels of galactose-deficient IgA1 among the different clinical and pathologic grading groups. The values of the area under the curve for galactose-deficient IgA1 levels were 0.976 (95% CI, 0.953-1.000). The cutoff point for galactose-deficient IgA1 levels was 0.125, with a sensitivity of 87.5% and a specificity of 83.3%, with a positive predictive value of 92.6% and a negative predictive value of 73.5% (P < 0.01). Children with IgAN presented serum galactose-deficient IgA1, which has shown no relationship with the clinical manifestations and pathologic grading of the disease. Detection of serum galactose-deficient IgA1 levels by vicia villosa lectin binding enzyme-linked immunosorbent assay has a certain clinical value in diagnosis of children with IgAN.

  17. Performance on immunoglobulin IgG, IgA, and IgM tests in CAP survey specimens.

    PubMed

    Ritchie, R F; Rippey, J H

    1982-10-01

    The performance of participants in nine consecutive College of American Pathologists (CAP) Survey specimens during 1979-1981 are listed for IgA, IgG, and IgM. The majority of participants used either radial immunodiffusion (RID) (51.4%) or nephelometric kits (33.6 per cent) manufactured by major firms and reported results in mass units (93.5 per cent). When tabulated by kit, prominent differences in performance were noticed. Furthermore, definite trends in methods employed were evident during the two-year period.

  18. Prey type, vibrations and handling interactively influence spider silk expression.

    PubMed

    Blamires, S J; Chao, I-C; Tso, I-M

    2010-11-15

    The chemical and mechanical properties of spider major ampullate (MA) silks vary in response to different prey, mostly via differential expression of two genes - MaSp1 and MaSp2 - although the spinning process exerts additional influence over the mechanical properties of silk. The prey cues that initiate differential gene expression are unknown. Prey nutrients, vibratory stimuli and handling have been suggested to be influential. We performed experiments to decouple the vibratory stimuli and handling associated with high and low kinetic energy prey (crickets vs flies) from their prey nutrients to test the relative influence of each as inducers of silk protein expression in the orb web spider Nephila pilipes. We found that the MA silks from spiders feeding on live crickets had greater percentages of glutamine, serine, alanine and glycine than those from spiders feeding on live flies. Proline composition of the silks was unaffected by feeding treatment. Increases in alanine and glycine in the MA silks of the live-cricket-feeding spiders indicate a probable increase in MaSp1 gene expression. The amino acid compositions of N. pilipes feeding on crickets with fly stimuli and N. pilipes feeding on flies with cricket stimuli did not differ from each other or from pre-treatment responses, so these feeding treatments did not induce differential MaSp expression. Our results indicate that cricket vibratory stimuli and handling interact with nutrients to induce N. pilipes to adjust their gene expression to produce webs with mechanical properties appropriate for the retention of this prey. This shows that spiders can genetically alter their silk chemical compositions and, presumably, mechanical properties upon exposure to different prey types. The lack of any change in proline composition with feeding treatment in N. pilipes suggests that the MaSp model determined for Nephila clavipes is not universally applicable to all Nephila.

  19. Evaluation of the diagnostic value of measuring IgG, IgM, and IgA antibodies to mycobacterial A60 antigen in active tuberculosis.

    PubMed

    Ben-selma, Walid; Harizi, Hedi; Marzouk, Manel; Ben Kahla, Imen; Ben Lazreg, Foued; Ferjeni, Asma; Boukadida, Jalel

    2010-09-01

    The purpose of the present study was to evaluate the clinical usefulness of detection of serum immunoglobulin A (IgA), IgG, and IgM antibodies raised against the mycobacterial A60 antigen for the diagnosis and discrimination of active tuberculosis (TB) from other pulmonary diseases. Three commercially available ELISA kits (IgA, IgG, and IgM) (ANDA Biologicals, Strasbourg, France) were evaluated simultaneously in 246 serum samples from 3 groups of patients: group I, 171 patients with active TB (128 pulmonary TB and 43 extrapulmonary TB); group II, 73 patients with pulmonary non-TB diseases; and group III, 2 leprosies patients. The sensitivities of tests ranged from 31.3% (IgA) to 94% (IgG) in pulmonary TB patients and from 21% (IgA) to 84% (IgG) in extrapulmonary TB patients. The specificities of assays varied from 92% (IgG) to 96% (IgA) in the pulmonary non-TB group. Combination of IgG with IgA and/or IgM does not improve its sensitivity. Clinical use of the A60-based serodiagnostic IgG assay is of great value for the rapid diagnosis and discrimination between active TB and pulmonary non-TB diseases. Moreover, this test could be used to increase diagnostic accuracy, especially for smear-negative TB cases, which are difficult to diagnose.

  20. Who's for dinner? High-throughput sequencing reveals bat dietary differentiation in a biodiversity hotspot where prey taxonomy is largely undescribed.

    PubMed

    Burgar, Joanna M; Murray, Daithi C; Craig, Michael D; Haile, James; Houston, Jayne; Stokes, Vicki; Bunce, Michael

    2014-08-01

    Effective management and conservation of biodiversity requires understanding of predator-prey relationships to ensure the continued existence of both predator and prey populations. Gathering dietary data from predatory species, such as insectivorous bats, often presents logistical challenges, further exacerbated in biodiversity hot spots because prey items are highly speciose, yet their taxonomy is largely undescribed. We used high-throughput sequencing (HTS) and bioinformatic analyses to phylogenetically group DNA sequences into molecular operational taxonomic units (MOTUs) to examine predator-prey dynamics of three sympatric insectivorous bat species in the biodiversity hotspot of south-western Australia. We could only assign between 4% and 20% of MOTUs to known genera or species, depending on the method used, underscoring the importance of examining dietary diversity irrespective of taxonomic knowledge in areas lacking a comprehensive genetic reference database. MOTU analysis confirmed that resource partitioning occurred, with dietary divergence positively related to the ecomorphological divergence of the three bat species. We predicted that bat species' diets would converge during times of high energetic requirements, that is, the maternity season for females and the mating season for males. There was an interactive effect of season on female, but not male, bat species' diets, although small sample sizes may have limited our findings. Contrary to our predictions, females of two ecomorphologically similar species showed dietary convergence during the mating season rather than the maternity season. HTS-based approaches can help elucidate complex predator-prey relationships in highly speciose regions, which should facilitate the conservation of biodiversity in genetically uncharacterized areas, such as biodiversity hotspots.

  1. Modulation in Persistent Organic Pollutant Concentration and Profile by Prey Availability and Reproductive Status in Southern Resident Killer Whale Scat Samples.

    PubMed

    Lundin, Jessica I; Ylitalo, Gina M; Booth, Rebecca K; Anulacion, Bernadita; Hempelmann, Jennifer A; Parsons, Kim M; Giles, Deborah A; Seely, Elizabeth A; Hanson, M Bradley; Emmons, Candice K; Wasser, Samuel K

    2016-06-21

    Persistent organic pollutants (POPs), specifically PCBs, PBDEs, and DDTs, in the marine environment are well documented, however accumulation and mobilization patterns at the top of the food-web are poorly understood. This study broadens the understanding of POPs in the endangered Southern Resident killer whale population by addressing modulation by prey availability and reproductive status, along with endocrine disrupting effects. A total of 140 killer whale scat samples collected from 54 unique whales across a 4 year sampling period (2010-2013) were analyzed for concentrations of POPs. Toxicant measures were linked to pod, age, and birth order in genotyped individuals, prey abundance using open-source test fishery data, and pregnancy status based on hormone indices from the same sample. Toxicant concentrations were highest and had the greatest potential for toxicity when prey abundance was the lowest. In addition, these toxicants were likely from endogenous lipid stores. Bioaccumulation of POPs increased with age, with the exception of presumed nulliparous females. The exceptional pattern may be explained by females experiencing unobserved neonatal loss. Transfer of POPs through mobilization of endogenous lipid stores during lactation was highest for first-borns with diminished transfer to subsequent calves. Contrary to expectation, POP concentrations did not demonstrate an associated disruption of thyroid hormone, although this association may have been masked by impacts of prey abundance on thyroid hormone concentrations. The noninvasive method for measuring POP concentrations in killer whales through scat employed in this study may improve toxicant monitoring in the marine environment and promote conservation efforts.

  2. The sequential appearance of IgG subclasses and IgE during the course of Trichinella spiralis infection.

    PubMed Central

    Ljungström, I; Hammarström, L; Kociecka, W; Smith, C I

    1988-01-01

    Earlier studies have shown that IgG1 and IgG4 are the dominant IgG subclasses in the specific response during a chronic helminthic infection. It has also been suggested that IgG4 production results from chronic or repetitive antigenic stimulation and a correlation between IgG4 and IgE levels exists. An outbreak of Trichinella spiralis infection in Poland provided the opportunity to follow the sequential appearance of the IgG subclass and IgE responses in 15 patients during the early stage of Trichinella infection and to compare these observations in sera obtained one year later from the same patients. The results show that the sequential appearance of the IgG subclasses were IgG1 before IgG3 and IgG3 before IgG4. IgG1 antibodies dominated the immune response in all patients. A statistically significant increase in the number of IgG4 positive sera was observed in patients during the chronic stage compared to the findings during the early stage of infection (13% vs 73%; p less than 0.001), supporting the view that IgG4 results from a chronic antigenic stimulation. A correlation between the appearance of IgG4 and IgE was not found. The highest levels of IgE were seen in the first serum samples obtained, with a decrease during the course of infection. PMID:3224442

  3. The clinical significance of IgA rheumatoid factor in idiopathic IgA mesangial nephropathy (Berger's disease).

    PubMed

    Sinico, R A; Fornasieri, A; Maldifassi, P; Colasanti, G; D'Amico, G

    1988-10-01

    IgA rheumatoid factor, IgA and IgG immune complexes were measured in 119 patients with IgA nephropathy. IgA rheumatoid factor was detected in 62/119 (52%) patients and in 92/265 (35%) serum samples. There was a good correlation (p less than 0.001) between the presence of IgA rheumatoid factor and the presence as well as levels of IgG immune complexes, but not between levels of IgA rheumatoid factor and other clinical or immunological parameters. However, higher levels of serum IgA were found in the subgroup of patients with constantly positive IgA rheumatoid factor. Using aggregated human IgG, we could not demonstrate antiglobulin activity in renal biopsy specimens from 36 patients. These results suggest that IgA rheumatoid factor does not play a primary role in renal damage in IgA nephropathy, but could simply reflect a response to IgG immune complexes in a disorder characterized by abnormalities of IgA production. Nevertheless, the presence of circulating IgA rheumatoid factor in a substantial proportion of patients, especially in those with features of polyclonal IgA activation, provides additional evidence for a general perturbation of IgA metabolism in this disease and could represent an antigen-specific system with which to study regulation of IgA synthesis.

  4. Effect of resource subsidies on predator-prey population dynamics: a mathematical model.

    PubMed

    Nevai, Andrew L; Van Gorder, Robert A

    2012-01-01

    The influence of a resource subsidy on predator-prey interactions is examined using a mathematical model. The model arises from the study of a biological system involving arctic foxes (predator), lemmings (prey), and seal carcasses (subsidy). In one version of the model, the predator, prey and subsidy all occur in the same location; in a second version, the predator moves between two patches, one containing only the prey and the other containing only the subsidy. Criteria for feasibility and stability of the different equilibrium states are studied both analytically and numerically. At small subsidy input rates, there is a minimum prey carrying capacity needed to support both predator and prey. At intermediate subsidy input rates, the predator and prey can always coexist. At high subsidy input rates, the prey cannot persist even at high carrying capacities. As predator movement increases, the dynamic stability of the predator-prey-subsidy interactions also increases.

  5. Female condoms.

    PubMed

    Bounds, W

    1997-06-01

    Early versions of a female condom were available in the 1920s and 1960s, but they were little used and soon forgotten. It took the arrival of AIDS, and the urgent need for a wider range of female-controlled barrier techniques, to rekindle scientific interest in this method. In the 1980s, three groups in Europe and the USA began development of new female condom designs, comprising 'Femidom (Reality)', the 'Bikini Condom', and 'Women's Choice'. Apart from differences in their physical design, Femidom differs from the others in that it is made of a polyurethane membrane, which has several advantages over latex. Of the three, Femidom is the most advanced in terms of development and clinical testing, and it is the only one to have reached the marketing stage. Laboratory studies and clinical trials suggest that its contraceptive efficacy is similar to that documented for the male condom, though a direct comparison is not possible because no comparative clinical trials have, as yet, been undertaken. Reported 'typical-use' pregnancy rates range from 12.4 to 22.2% at 6 months of use in the USA and Latin America, respectively, while a study in the UK observed a rate of 15% at 12 months. As with all barrier methods, most failures appear to be associated with poor compliance or incorrect use. 'Perfect-use' pregnancy rates were substantially lower, indicating that Femidom can be very effective, if used consistently and correctly. Evidence for Femidom's effectiveness to protect against transmission of sexual disease-causing organisms, including HIV, is still very limited and based largely on laboratory studies. Whilst, in theory, the condom should confer reliable protection, its efficacy in clinical use will depend upon correct and consistent use and upon the product's ability to maintain an effective physical barrier throughout penetrative intercourse. In this respect, the results of recent and ongoing clinical studies are expected with much interest. How valuable Femidom will

  6. Comparative growth and development of spiders reared on live and dead prey.

    PubMed

    Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C

    2013-01-01

    Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific.

  7. Electric Eels Concentrate Their Electric Field to Induce Involuntary Fatigue in Struggling Prey.

    PubMed

    Catania, Kenneth C

    2015-11-16

    Nature is replete with predator venoms that immobilize prey by targeting ion channels. Electric eels (Electrophorus electricus) take a different tactic to accomplish the same end. Striking eels emit electricity in volleys of 1 ms, high-voltage pulses. Each pulse is capable of activating prey motor neuron efferents, and hence muscles. In a typical attack, eel discharges cause brief, immobilizing tetanus, allowing eels to swallow small prey almost immediately. Here I show that when eels struggle with large prey or fish held precariously, they commonly curl to bring their own tail to the opposite side of prey, sandwiching it between the two poles of their powerful electric organ. They then deliver volleys of high-voltage pulses. Shortly thereafter, eels juggle prey into a favorable position for swallowing. Recordings from electrodes placed within prey items show that this curling behavior at least doubles the field strength within shocked prey, most likely ensuring reliable activation of the majority of prey motor neurons. Simulated pulse trains, or pulses from an eel-triggered stimulator, applied to a prey muscle preparations result in profound muscle fatigue and loss of contractile force. Consistent with this result, video recordings show that formerly struggling prey are temporarily immobile after this form of attack, allowing the manipulation of prey that might otherwise escape. These results reveal a unique use of electric organs to a unique end; eels superimpose electric fields from two poles, ensuring maximal remote activation of prey efferents that blocks subsequent prey movement by inducing involuntary muscle fatigue.

  8. Sequential assessment of prey through the use of multiple sensory cues by an eavesdropping bat

    NASA Astrophysics Data System (ADS)

    Page, Rachel A.; Schnelle, Tanja; Kalko, Elisabeth K. V.; Bunge, Thomas; Bernal, Ximena E.

    2012-06-01

    Predators are often confronted with a broad diversity of potential prey. They rely on cues associated with prey quality and palatability to optimize their hunting success and to avoid consuming toxic prey. Here, we investigate a predator's ability to assess prey cues during capture, handling, and consumption when confronted with conflicting information about prey quality. We used advertisement calls of a preferred prey item (the túngara frog) to attract fringe-lipped bats, Trachops cirrhosus, then offered palatable, poisonous, and chemically manipulated anurans as prey. Advertisement calls elicited an attack response, but as bats approached, they used additional sensory cues in a sequential manner to update their information about prey size and palatability. While both palatable and poisonous small anurans were readily captured, large poisonous toads were approached but not contacted suggesting the use of echolocation for assessment of prey size at close range. Once prey was captured, bats used chemical cues to make final, post-capture decisions about whether to consume the prey. Bats dropped small, poisonous toads as well as palatable frogs coated in toad toxins either immediately or shortly after capture. Our study suggests that echolocation and chemical cues obtained at close range supplement information obtained from acoustic cues at long range. Updating information about prey quality minimizes the occurrence of costly errors and may be advantageous in tracking temporal and spatial fluctuations of prey and exploiting novel food sources. These findings emphasize the sequential, complex nature of prey assessment that may allow exploratory and flexible hunting behaviors.

  9. Comparative Growth and Development of Spiders Reared on Live and Dead Prey

    PubMed Central

    Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C.

    2013-01-01

    Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific. PMID:24386248

  10. [Genetics of mesangial IgA nephropathy].

    PubMed

    Delbarba, Elisa; Pedroni, Bruno; Dallera, Nadia; Izzi, Claudia; Scolari, Francesco

    2015-01-01

    IgA nephropathy is the most common form of primary glomerulonephritis, with a variable prevalence depending on the geographic area of examination. Marked differences in disease prevalence has suggested that genetics could play a role in the pathogenesis of the disease, indicating the existence of susceptibility genes detected with different frequencies in geographically separated populations. Moreover, familial forms of IgAN have been reported worldwide, in sibling pairs, families and extended pedigrees belonging to geographically isolated populations. In this article we describe recent discoveries in genetic studies on IgAN. If candidate-gene association studies require first survey on the pathogenesis of the disease, since the candidate loci are selected on the basis of information gathered from traditional biology, the linkage analysis consist in an alternative approach. Several susceptibility loci have been identified in pedigrees segregating for IgAN, but not the causative mutations of the disease. Further progress in the field of knowledge about the genetics of IgAN has recently been obtained by the application of genome-wide association studies (GWAS) in large cohorts of cases and controls of IgAN. GWAS have identified multiple susceptibility loci coding for genes involved in critical mechanisms for the development of IgAN and, accordingly, have shed new light on the biology of the disease, revealing unknown pathogenic pathways. The close connection between IgAN and many autoimmune diseases has been demonstrated. Moreover, these studies have made the correlation of genetic risk score of developing IgAN with the geo-epidemiological aspect of the disease possible. The goal of the integrated genomic approach will be to discover new potential therapeutic targets.

  11. Aberrant IgA1 Glycosylation in IgA Nephropathy: A Systematic Review

    PubMed Central

    Sun, Qiang; Zhang, Zhenhai; Liu, Xiaorong

    2016-01-01

    Objective Galactose-deficient IgA1 was evaluated in patients with IgA nephropathy(IgAN) and controls in order to determine the predictive value of galactose-deficient IgA1 in cases of IgA nephropathy. Methods PubMed, EMBASE, Cochrane central register of controlled trials, CNKI, CBM disc, and VIP database were searched to identify eligible studies that evaluated a difference in aberrant IgA1 glycosylation in IgAN patients compared with controls. A meta-analysis was conducted to evaluate the impact of galactose-deficient IgA1(Gd-IgA1) levels in different groups. Results A total of 22 studies (n = 1657) met inclusion criteria. The mean Newcastle-Ottawa Scale (NOS) score was 7.2 and ranged from 6 to 8. The standard mean difference(SMD) in the meta-analysis of 20 studies of the level of Gd-IgA1 in the serum and/or supernatant of cultured cells was higher in the IgAN group compared with healthy controls as well as in those with other renal diseases (SMD = 1.76, 95% CI = 1.18–2.34, P<0.00001; SMD = 1.05, 95% CI = 0.05–2.04, P = 0.04). The data synthesis suggested that IgAN patients had similar levels of serum Gd-IgA1, with no significant differences, compared with first-degree relatives and Henoch-Schonlein purpura nephritis (HSPN) patients (MD = 0.04, 95% CI = 0.00–0.08, P = 0.05; MD = -46.03, 95% CI = -217.70–125.64, P = 0.60). In addition, the combined MD of 5 studies indicated that there were no significant differences in Gd-IgA1 levels among patients with varying severities of IgAN (MD = 0.02, 95% CI = -0.02–0.05, P = 0.28). Conclusions The pooled evidence suggests that the level of Gd-IgA1 in the serum or supernatant of cultured cells from peripheral blood or tonsils may be a useful biomarker for predicting IgA nephropathy, though the level of Gd-IgA1 was not significantly associated with disease severity. PMID:27870872

  12. Specific IgE response in patients with brucellosis.

    PubMed Central

    Araj, G. F.; Lulu, A. R.; Khateeb, M. I.; Haj, M.

    1990-01-01

    In the search to find discriminative serological markers to differentiate between patients with acute brucellosis and those with chronic brucellosis, an enzyme-linked immunosorbent assay (ELISA) was used to determine and compare the brucella-specific IgE response in 80 sera from patients with acute brucellosis, 37 sera from patients with chronic brucellosis, 26 sera from patients with positive blood cultures for bacteria other than brucella and 51 sera from healthy controls. The IgE findings were compared to brucella-specific IgG, IgM, IgA and IgG1-4 demonstrated by ELISA, and to microagglutination test (MAT) results. Elevated (positive) antibrucella IgE titres were detected in 89 and 81% of sera from patients with acute and chronic brucellosis respectively. The predominant antibodies found in patients with acute brucellosis were of the IgG, IgM, IgA, IgE, IgG1 and IgG3 types while in chronic brucellosis IgG, IgA, IgE and IgG4 were found. Although IgE can be detected in patients with brucellosis, it does not discriminate between the acute and chronic stages of the disease. PMID:2249721

  13. IgG4-related prostatitis progressed from localized IgG4-related lymphadenopathy

    PubMed Central

    Li, Dujuan; Kan, Yunzhen; Fu, Fangfang; Wang, Shuhuan; Shi, Ligang; Liu, Jie; Kong, Lingfei

    2015-01-01

    Immunoglobulin G4-related disease (IgG4-RD) is a recently described inflammatory disease involving multiple organs. Prostate involvement with IgG4-RD is very rare. In this report, we describe a case of IgG4-related prostatitis progressed from localized IgG4-related lymphadenopathy. This patient was present with urine retention symptoms. MRI and CT examination revealed the prostatic enlargement and the multiple lymphadenopathy. Serum IgG4 levels were elevated. Prostatic tissue samples resected both this time and less than 1 year earlier showed the same histological type of prostatitis with histopathologic and immunohistochemical findings characteristic of IgG4-RD. The right submandibular lymph nodes excised 2 years earlier were eventually proven to be follicular hyperplasia-type IgG4-related lymphadenopathy. This is the first case of IgG4-RD that began as localized IgG4-related lymphadenopathy and progressed into a systemic disease involving prostate and multiple lymph nodes. This patient showed a good response to steroid therapy. This leads us to advocate a novel pathogenesis of prostatitis, and a novel therapeutic approach against prostatitis. Pathologists and urologists should consider this disease entity in the patients with elevated serum IgG4 levels and the symptoms of prostatic hyperplasia to avoid ineffective medical or unnecessary surgical treatment. PMID:26617921

  14. IgG4-related prostatitis progressed from localized IgG4-related lymphadenopathy.

    PubMed

    Li, Dujuan; Kan, Yunzhen; Fu, Fangfang; Wang, Shuhuan; Shi, Ligang; Liu, Jie; Kong, Lingfei

    2015-01-01

    Immunoglobulin G4-related disease (IgG4-RD) is a recently described inflammatory disease involving multiple organs. Prostate involvement with IgG4-RD is very rare. In this report, we describe a case of IgG4-related prostatitis progressed from localized IgG4-related lymphadenopathy. This patient was present with urine retention symptoms. MRI and CT examination revealed the prostatic enlargement and the multiple lymphadenopathy. Serum IgG4 levels were elevated. Prostatic tissue samples resected both this time and less than 1 year earlier showed the same histological type of prostatitis with histopathologic and immunohistochemical findings characteristic of IgG4-RD. The right submandibular lymph nodes excised 2 years earlier were eventually proven to be follicular hyperplasia-type IgG4-related lymphadenopathy. This is the first case of IgG4-RD that began as localized IgG4-related lymphadenopathy and progressed into a systemic disease involving prostate and multiple lymph nodes. This patient showed a good response to steroid therapy. This leads us to advocate a novel pathogenesis of prostatitis, and a novel therapeutic approach against prostatitis. Pathologists and urologists should consider this disease entity in the patients with elevated serum IgG4 levels and the symptoms of prostatic hyperplasia to avoid ineffective medical or unnecessary surgical treatment.

  15. IgG4-related skin manifestations in patients with IgG4-related disease.

    PubMed

    Ikeda, Tetsuya; Oka, Masahiro; Shimizu, Hideki; Hatakeyama, Mayumi; Kanki, Haruhisa; Kunisada, Makoto; Tsuji, Goh; Morinobu, Akio; Kumagai, Shunichi; Azumi, Atsushi; Negi, Akira; Nishigori, Chikako

    2013-04-01

    We describe two cases of IgG4-related disease associated with skin manifestations with IgG4-positive plasma cells. The first patient was a 52-year-old woman with a 3-year history of IgG4-related sialadenitis who presented with pruritic, indurated erythematous lesions on the auricle, postauricular and submandibular regions and neck. A skin biopsy showed infiltration of IgG4-positive plasma cells in the subcutaneous tissue. The second patient was a 53-year-old woman with IgG4-related lesions in the ocular adnexal tissues and nasal cavity who presented with pruritic, indurated erythema on the cheek and submandibular region. Histopathological examination of a skin biopsy revealed a dense, patchy infiltrate comprised of lymphocytes, IgG4-positive plasma cells and eosinophils around blood vessels and sweat glands in the entire dermis and subcutis. The skin lesions in these cases were considered to be skin manifestations of IgG4-related disease. The findings of these two cases together with the three reported cases of IgG4-related disease with skin manifestations in the literature suggest that IgG4-related skin lesions may appear on the scalp, face, neck, auricle and postauricular regions during the course of IgG4-related disease.

  16. A dedicated visual pathway for prey detection in larval zebrafish

    PubMed Central

    Semmelhack, Julia L; Donovan, Joseph C; Thiele, Tod R; Kuehn, Enrico; Laurell, Eva; Baier, Herwig

    2014-01-01

    Zebrafish larvae show characteristic prey capture behavior in response to small moving objects. The neural mechanism used to recognize objects as prey remains largely unknown. We devised a machine learning behavior classification system to quantify hunting kinematics in semi-restrained animals exposed to a range of virtual stimuli. Two-photon calcium imaging revealed a small visual area, AF7, that was activated specifically by the optimal prey stimulus. This pretectal region is innervated by two types of retinal ganglion cells, which also send collaterals to the optic tectum. Laser ablation of AF7 markedly reduced prey capture behavior. We identified neurons with arbors in AF7 and found that they projected to multiple sensory and premotor areas: the optic tectum, the nucleus of the medial longitudinal fasciculus (nMLF) and the hindbrain. These findings indicate that computations in the retina give rise to a visual stream which transforms sensory information into a directed prey capture response. DOI: http://dx.doi.org/10.7554/eLife.04878.001 PMID:25490154

  17. Cooperative prey herding by the pelagic dolphin, Stenella longirostris.

    PubMed

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

    2009-01-01

    Sonar techniques were used to quantitatively observe foraging predators and their prey simultaneously in three dimensions. Spinner dolphins foraged at night in highly coordinated groups of 16-28 individuals using strict four-dimensional patterns to increase prey density by up to 200 times. Herding exploited the prey's own avoidance behavior to achieve food densities not observed otherwise. Pairs of dolphins then took turns feeding within the aggregation that was created. Using a proxy estimate of feeding success, it is estimated that each dolphin working in concert has more access to prey than it would if feeding individually, despite the costs of participating in the group maneuvers, supporting the cooperation hypothesis. Evidence of a prey density threshold for feeding suggests that feedback from the environment may be enough to favor the evolution of cooperation. The remarkable degree of coordination shown by foraging spinner dolphins, the very strict geometry, tight timing, and orderly turn taking, indicates the advantage conferred by this strategy and the constraints placed upon it. The consistent appearance of this behavior suggests that it may be a critical strategy for energy acquisition by spinner dolphins in energy poor featureless environments in the tropical Pacific Ocean.

  18. Prey scan at random to evade observant predators.

    PubMed Central

    Scannell, J.; Roberts, G.; Lazarus, J.

    2001-01-01

    Anti-predator scans by animals occur with very irregular timing, so that the initiation of scans resembles a random, Poisson-like, process. At first sight, this seems both dangerous (predators could exploit the long intervals) and wastefull (scans after very short intervals are relatively uninformative). We explored vigilance timing using a new model that allows both predators and prey to vary their behaviour. Given predators that attack at random with respect to prey behaviour, constant inter-scan intervals minimize predation risk. However, if prey scan regularly to minimize their risk from randomly attacking predators, they become more vulnerable to predators that initiate attacks when the inter-scan intervals begin. If, in order to defeat this tactic, prey choose extremely variable inter-scan intervals, they become more vulnerable to predators who wait for long intervals before launching attacks. Only if predators can monitor the variability of inter-scan intervals and either attack immediately (if variability is too low) or wait for long intervals to attack (if variability is too high) does the empirically observed pattern of Poisson-like scanning become the optimal prey strategy. PMID:11296867

  19. Bacterial predator–prey dynamics in microscale patchy landscapes

    PubMed Central

    Rotem, Or; Jurkevitch, Edouard; Dekker, Cees

    2016-01-01

    Soil is a microenvironment with a fragmented (patchy) spatial structure in which many bacterial species interact. Here, we explore the interaction between the predatory bacterium Bdellovibrio bacteriovorus and its prey Escherichia coli in microfabricated landscapes. We ask how fragmentation influences the prey dynamics at the microscale and compare two landscape geometries: a patchy landscape and a continuous landscape. By following the dynamics of prey populations with high spatial and temporal resolution for many generations, we found that the variation in predation rates was twice as large in the patchy landscape and the dynamics was correlated over shorter length scales. We also found that while the prey population in the continuous landscape was almost entirely driven to extinction, a significant part of the prey population in the fragmented landscape persisted over time. We observed significant surface-associated growth, especially in the fragmented landscape and we surmise that this sub-population is more resistant to predation. Our results thus show that microscale fragmentation can significantly influence bacterial interactions. PMID:26865299

  20. Permanence in an intraguild predation model with prey switching.

    PubMed

    Zabalo, Joaquin

    2012-09-01

    Intraguild predation, a form of omnivory that can occur in simple food webs when one species preys on and competes for limiting resources with another species, can have either a stabilizing effect (McCann and Hastings in Proc. R. Soc. Lond. B 264:1249-1254, 1997) or a destabilizing effect (Holt and Polis in Am. Nat. 149:745-764, 1997), depending on the assumptions of the system. Another type of behavior that has been observed in simple food web experiments (Murdoch in Ecol. Monogr. 39:335-354, 1969) is prey switching. Prey switching can occur when the predator prefers the most abundant prey. This has also been shown to be capable of having either a stabilizing effect or a destabilizing effect and even possibly lead to predator extinction (VanLeeuwen et al. in Ecology 88:1571-1581, 2007). Therefore, it is clear that incorporating prey switching into an intraguild predation model could lead to unexpected consequences. In this paper, we propose and explore such a model.

  1. 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

  2. Perceptual advertisement by the prey of stalking or ambushing predators.

    PubMed

    Broom, Mark; Ruxton, Graeme D

    2012-12-21

    There has been previous theoretical explorations of the stability of signals by prey that they have detected a stalking or ambush predator, where such perceptual advertisement dissuades the predator from attacking. Here we use a game theoretical model to extend the theory to consider some empirically-motivated complexities: (i) many perceptual advertisement signals appear to have the potential to vary in intensity, (ii) higher intensity signals are likely to be most costly to produce, and (iii) some high-cost signals (such as staring directly at the predator) can only be utilised if the prey is very confident of the existence of a nearby predator (that is, there are reserved or unfakable signals). We demonstrate that these complexities still allow for stable signalling. However, we do not find solutions where prey use a range of signal intensities to signal different degrees of confidence in the proximity of a predator; with prey simply adopting a binary response of not signalling or always signalling at the same fixed level. However this fixed level will not always be the cheapest possible signal, and we predict that prey that require more certainty about proximity of a predator will use higher-cost signals. The availability of reserved signals does not prohibit the stability of signalling based on lower-cost signals, but we also find circumstances where only the reserved signal is used. We discuss the potential to empirically test our model predictions, and to develop theory further to allow perceptual advertisement to be combined with other signalling functions.

  3. Prey Capture Ecology of the Cubozoan Carukia barnesi

    PubMed Central

    Sachlikidis, Nik; Jones, Rhondda

    2015-01-01

    Adult Carukia barnesi medusae feed predominantly on larval fish; however, their mode of prey capture seems more complex than previously described. Our findings revealed that during light conditions, this species extends its tentacles and ‘twitches’ them frequently. This highlights the lure-like nematocyst clusters in the water column, which actively attract larval fish that are consequently stung and consumed. This fishing behavior was not observed during dark conditions, presumably to reduce energy expenditure when they are not luring visually oriented prey. We found that larger medusae have longer tentacles; however, the spacing between the nematocyst clusters is not dependent on size, suggesting that the spacing of the nematocyst clusters is important for prey capture. Additionally, larger specimens twitch their tentacles more frequently than small specimens, which correlate with their recent ontogenetic prey shift from plankton to larval fish. These results indicate that adult medusae of C. barnesi are not opportunistically grazing in the water column, but instead utilize sophisticated prey capture techniques to specifically target larval fish. PMID:25970583

  4. Incorporating prey refuge in a prey-predator model with a Holling type I functional response: random dynamics and population outbreaks.

    PubMed

    Gkana, Amalia; Zachilas, Loukas

    2013-09-01

    A prey-predator discrete-time model with a Holling type I functional response is investigated by incorporating a prey refuge. It is shown that a refuge does not always stabilize prey-predator interactions. A prey refuge in some cases produces even more chaotic, random-like dynamics than without a refuge and prey population outbreaks appear. Stability analysis was performed in order to investigate the local stability of fixed points as well as the several local bifurcations they undergo. Numerical simulations such as parametric basins of attraction, bifurcation diagrams, phase plots and largest Lyapunov exponent diagrams are executed in order to illustrate the complex dynamical behavior of the system.

  5. Generation and Characterization of Antibodies against Asian Elephant (Elephas maximus) IgG, IgM, and IgA

    PubMed Central

    Humphreys, Alan F.; Tan, Jie; Peng, RongSheng; Benton, Susan M.; Qin, Xiang; Worley, Kim C.; Mikulski, Rose L.; Chow, Dar-Chone; Palzkill, Timothy G.; Ling, Paul D.

    2015-01-01

    Asian elephant (Elephas maximus) immunity is poorly characterized and understood. This gap in knowledge is particularly concerning as Asian elephants are an endangered species threatened by a newly discovered herpesvirus known as elephant endotheliotropic herpesvirus (EEHV), which is the leading cause of death for captive Asian elephants born after 1980 in North America. While reliable diagnostic assays have been developed to detect EEHV DNA, serological assays to evaluate elephant anti-EEHV antibody responses are lacking and will be needed for surveillance and epidemiological studies and also for evaluating potential treatments or vaccines against lethal EEHV infection. Previous studies have shown that Asian elephants produce IgG in serum, but they failed to detect IgM and IgA, further hampering development of informative serological assays for this species. To begin to address this issue, we determined the constant region genomic sequence of Asian elephant IgM and obtained some limited protein sequence information for putative serum IgA. The information was used to generate or identify specific commercial antisera reactive against IgM and IgA isotypes. In addition, we generated a monoclonal antibody against Asian elephant IgG. These three reagents were used to demonstrate that all three immunoglobulin isotypes are found in Asian elephant serum and milk and to detect antibody responses following tetanus toxoid booster vaccination or antibodies against a putative EEHV structural protein. The results indicate that these new reagents will be useful for developing sensitive and specific assays to detect and characterize elephant antibody responses for any pathogen or vaccine, including EEHV. PMID:25658336

  6. A Reassessment of IgM Memory Subsets in Humans.

    PubMed

    Bagnara, Davide; Squillario, Margherita; Kipling, David; Mora, Thierry; Walczak, Aleksandra M; Da Silva, Lucie; Weller, Sandra; Dunn-Walters, Deborah K; Weill, Jean-Claude; Reynaud, Claude-Agnès

    2015-10-15

    From paired blood and spleen samples from three adult donors, we performed high-throughput VH sequencing of human B cell subsets defined by IgD and CD27 expression: IgD(+)CD27(+) ("marginal zone [MZ]"), IgD(-)CD27(+) ("memory," including IgM ["IgM-only"], IgG and IgA) and IgD(-)CD27(-) cells ("double-negative," including IgM, IgG, and IgA). A total of 91,294 unique sequences clustered in 42,670 clones, revealing major clonal expansions in each of these subsets. Among these clones, we further analyzed those shared sequences from different subsets or tissues for VH gene mutation, H-CDR3-length, and VH/JH usage, comparing these different characteristics with all sequences from their subset of origin for which these parameters constitute a distinct signature. The IgM-only repertoire profile differed notably from that of MZ B cells by a higher mutation frequency and lower VH4 and higher JH6 gene usage. Strikingly, IgM sequences from clones shared between the MZ and the memory IgG/IgA compartments showed a mutation and repertoire profile of IgM-only and not of MZ B cells. Similarly, all IgM clonal relationships (among MZ, IgM-only, and double-negative compartments) involved sequences with the characteristics of IgM-only B cells. Finally, clonal relationships between tissues suggested distinct recirculation characteristics between MZ and switched B cells. The "IgM-only" subset (including cells with its repertoire signature but higher IgD or lower CD27 expression levels) thus appear as the only subset showing precursor-product relationships with CD27(+) switched memory B cells, indicating that they represent germinal center-derived IgM memory B cells and that IgM memory and MZ B cells constitute two distinct entities.

  7. Silk wrapping of nuptial gifts as visual signal for female attraction in a crepuscular spider

    NASA Astrophysics Data System (ADS)

    Trillo, Mariana C.; Melo-González, Valentina; Albo, Maria J.

    2014-02-01

    An extensive diversity of nuptial gifts is known in invertebrates, but prey wrapped in silk is a unique type of gift present in few insects and spiders. Females from spider species prefer males offering a gift accepting more and longer matings than when males offered no gift. Silk wrapping of the gift is not essential to obtain a mating, but appears to increase the chance of a mating evidencing a particularly intriguing function of this trait. Consequently, as other secondary sexual traits, silk wrapping may be an important trait under sexual selection, if it is used by females as a signal providing information on male quality. We aimed to understand whether the white color of wrapped gifts is used as visual signal during courtship in the spider Paratrechalea ornata. We studied if a patch of white paint on the males' chelicerae is attractive to females by exposing females to males: with their chelicerae painted white; without paint; and with the sternum painted white (paint control). Females contacted males with white chelicerae more often and those males obtained higher mating success than other males. Thereafter, we explored whether silk wrapping is a condition-dependent trait and drives female visual attraction. We exposed good and poor condition males, carrying a prey, to the female silk. Males in poor condition added less silk to the prey than males in good condition, indicating that gift wrapping is an indicator of male quality and may be used by females to acquire information of the potential mate.

  8. Silk wrapping of nuptial gifts as visual signal for female attraction in a crepuscular spider.

    PubMed

    Trillo, Mariana C; Melo-González, Valentina; Albo, Maria J

    2014-02-01

    An extensive diversity of nuptial gifts is known in invertebrates, but prey wrapped in silk is a unique type of gift present in few insects and spiders. Females from spider species prefer males offering a gift accepting more and longer matings than when males offered no gift. Silk wrapping of the gift is not essential to obtain a mating, but appears to increase the chance of a mating evidencing a particularly intriguing function of this trait. Consequently, as other secondary sexual traits, silk wrapping may be an important trait under sexual selection, if it is used by females as a signal providing information on male quality. We aimed to understand whether the white color of wrapped gifts is used as visual signal during courtship in the spider Paratrechalea ornata. We studied if a patch of white paint on the males' chelicerae is attractive to females by exposing females to males: with their chelicerae painted white; without paint; and with the sternum painted white (paint control). Females contacted males with white chelicerae more often and those males obtained higher mating success than other males. Thereafter, we explored whether silk wrapping is a condition-dependent trait and drives female visual attraction. We exposed good and poor condition males, carrying a prey, to the female silk. Males in poor condition added less silk to the prey than males in good condition, indicating that gift wrapping is an indicator of male quality and may be used by females to acquire information of the potential mate.

  9. Anti-Acanthamoeba IgG, IgM, and IgA immunoreactivities in correlation to strain pathogenicity.

    PubMed

    Walochnik, J; Obwaller, A; Haller-Schober, E M; Aspöck, H

    2001-08-01

    Several representatives of the genus Acanthamoeba are known as causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. These occur predominantly in the immunocompromised host, but it is still unclear what primes the amoebae for pathogenicity. The aim of this study was to assess possible immunological differences between a highly pathogenic and a nonpathogenic Acanthamoeba strain. A total of 20 sera, including two sera of Acanthamoeba keratitis patients, were tested for anti-Acanthamoeba IgG, IgM, and IgA immunoreactivities using immunoblotting. All sera were positive for Acanthamoeba, revealing two predominant bands at 29 kDa and at 47 kDa, respectively. Interestingly, IgG and particularly IgA immunoreactivity enabled a clear discrimination between the pathogenic and nonpathogenic strains. Moreover, compared to the control sera, the two sera of Acanthamoeba keratitis patients showed rather weak immunoreactivities and they lacked the 29 kDa and the 47 kDa band in the IgA immunoblot against the pathogenic strain. The results of our study support the assumption that immunological predisposition might also be of importance in Acanthamoeba keratitis.

  10. Feeding behaviour of the nauplii of the marine calanoid copepod Paracartia grani Sars: Functional response, prey size spectrum, and effects of the presence of alternative prey

    PubMed Central

    Saiz, Enric

    2017-01-01

    Laboratory feeding experiments were conducted to study the functional response and prey size spectrum of the young naupliar stages of the calanoid copepod Paracartia grani Sars. Experiments were conducted on a range of microalgal prey of varying sizes and motility patterns. Significant feeding was found in all prey of a size range of 4.5–19.8 μm, with Holling type III functional responses observed for most prey types. The highest clearance rates occurred when nauplii fed on the dinoflagellate Heterocapsa sp. and the diatom Thalassiosira weissflogii (respectively, 0.61 and 0.70 mL ind-1 d-1), suggesting an optimal prey:predator ratio of 0.09. Additional experiments were conducted to examine the effects of the presence of alternative prey (either Heterocapsa sp. or Gymnodinium litoralis) on the functional response to the haptophyte Isochrysis galbana. In the bialgal mixtures, clearance and ingestion rates of I. galbana along the range of the functional response were significantly reduced as a result of selectivity towards the larger, alternative prey. Paradoxically, relatively large prey trigger a perception response in the nauplii, but most likely such prey cannot be completely ingested and a certain degree of sloppy feeding may occur. Our results are further evidence of the complex prey-specific feeding interactions that are likely to occur in natural assemblages with several available prey types. PMID:28257517

  11. Capture success and efficiency of dragonflies pursuing different types of prey.

    PubMed

    Combes, S A; Salcedo, M K; Pandit, M M; Iwasaki, J M

    2013-11-01

    The dynamics of predator-prey interactions vary enormously, due both to the heterogeneity of natural environments and to wide variability in the sensorimotor systems of predator and prey. In addition, most predators pursue a range of different types of prey, and most organisms are preyed upon by a variety of predators. We do not yet know whether predators employ a general kinematic and behavioral strategy, or whether they tailor their pursuits to each type of prey; nor do we know how widely prey differ in their survival strategies and sensorimotor capabilities. To gain insight into these questions, we compared aerial predation in 4 species of libelluid dragonflies pursuing 4 types of dipteran prey, spanning a range of sizes. We quantified the proportion of predation attempts that were successful (capture success), as well as the total time spent and the distance flown in pursuit of prey (capture efficiency). Our results show that dragonfly prey-capture success and efficiency both decrease with increasing size of prey, and that average prey velocity generally increases with size. However, it is not clear that the greater distances and times required for capturing larger prey are due solely to the flight performance (e.g., speed or evasiveness) of the prey, as predicted. Dragonflies initiated pursuits of large prey when they were located farther away, on average, as compared to small prey, and the total distance flown in pursuit was correlated with initial distance to the prey. The greater initial distances observed during pursuits of larger prey may arise from constraints on dragonflies' visual perception; dragonflies typically pursued prey subtending a visual angle of 1°, and rarely pursued prey at visual angles greater than 3°. Thus, dragonflies may be unable to perceive large prey flying very close to their perch (subtending a visual angle greater than 3-4°) as a distinct target. In comparing the performance of different dragonfly species that co-occur in the

  12. Fear on the move: predator hunting mode predicts variation in prey mortality and plasticity in prey spatial response.

    PubMed

    Miller, Jennifer R B; Ament, Judith M; Schmitz, Oswald J

    2014-01-01

    Ecologists have long searched for a framework of a priori species traits to help predict predator-prey interactions in food webs. Empirical evidence has shown that predator hunting mode and predator and prey habitat domain are useful traits for explaining predator-prey interactions. Yet, individual experiments have yet to replicate predator hunting mode, calling into question whether predator impacts can be attributed to hunting mode or merely species identity. We tested the effects of spider predators with sit-and-wait, sit-and-pursue and active hunting modes on grasshopper habitat domain, activity and mortality in a grassland system. We replicated hunting mode by testing two spider predator species of each hunting mode on the same grasshopper prey species. We observed grasshoppers with and without each spider species in behavioural cages and measured their mortality rates, movements and habitat domains. We likewise measured the movements and habitat domains of spiders to characterize hunting modes. We found that predator hunting mode explained grasshopper mortality and spider and grasshopper movement activity and habitat domain size. Sit-and-wait spider predators covered small distances over a narrow domain space and killed fewer grasshoppers than sit-and-pursue and active predators, which ranged farther distances across broader domains and killed more grasshoppers, respectively. Prey adjusted their activity levels and horizontal habitat domains in response to predator presence and hunting mode: sedentary sit-and-wait predators with narrow domains caused grasshoppers to reduce activity in the same-sized domain space; more mobile sit-and-pursue predators with broader domains caused prey to reduce their activity within a contracted horizontal (but not vertical) domain space; and highly mobile active spiders led grasshoppers to increase their activity across the same domain area. All predators impacted prey activity, and sit-and-pursue predators generated strong

  13. [Antinuclear antibodies, patterns and characteristics obtained by immunofluorescence. The importance of the IgA, IgM and IgG isotypes].

    PubMed

    Arcavi, Miriam; Dadone, Jorge

    2009-01-01

    The indirect immunofluorescence with epitelial cell line from human laryngeal carcinoma as substrate (IIF-HEp2) and anti-IgG or anti-total Ig as antisera, is the technique currently used for the detection of antinuclear antibodies. The most important antibodies for the diagnosis and follow-up of connective tissue diseases (CTD) are the IgG-ANA, while the IgM-ANA have no clinical relevance. However the IgA-ANA have not been thoroughly investigated so far. The aim of this work was to study the prevalence of different ANA isotypes of Ig antibodies in CTD patients and to evaluate the convenience of the use of monovalent or polyvalent conjugate. We examined the sera of 100 patients with different CTD by IIF-HEp2 and detected a prevalence of 38% IgA-ANA (titles > or = 1:80) and 12% IgM-ANA (titles < or = 1:160). In twenty nine cases we detected IgA-ANA in absence of IgM-ANA, and in 3 cases IgM-ANA in absence of IgA-ANA. In all the cases IgG-ANA were present. In 6 sera a change in the immunofluorescence pattern was observed while using anti-IgA conjugate, whereas in 3 the change was observed with the use of anti-IgM conjugate. Because of the high prevalence of ANA-IgA detected by IIF-HEp2, we emphasize the convenience of employing anti-total Ig in spite of anti-IgG conjugated until the role of ANA-IgA is dilucidated in CTD patients, in order to establish its relevance in the diagnosis, prognosis and follow-up of systemic rheumatic diseases.

  14. How sailfish use their bills to capture schooling prey

    PubMed Central

    Domenici, P.; Wilson, A. D. M.; Kurvers, R. H. J. M.; Marras, S.; Herbert-Read, J. E.; Steffensen, J. F.; Krause, S.; Viblanc, P. E.; Couillaud, P.; Krause, J.

    2014-01-01

    The istiophorid family of billfishes is characterized by an extended rostrum or ‘bill’. While various functions (e.g. foraging and hydrodynamic benefits) have been proposed for this structure, until now no study has directly investigated the mechanisms by which billfishes use their rostrum to feed on prey. Here, we present the first unequivocal evidence of how the bill is used by Atlantic sailfish (Istiophorus albicans) to attack schooling sardines in the open ocean. Using high-speed video-analysis, we show that (i) sailfish manage to insert their bill into sardine schools without eliciting an evasive response and (ii) subsequently use their bill to either tap on individual prey targets or to slash through the school with powerful lateral motions characterized by one of the highest accelerations ever recorded in an aquatic vertebrate. Our results demonstrate that the combination of stealth and rapid motion make the sailfish bill an extremely effective feeding adaptation for capturing schooling prey. PMID:24759865

  15. Bacteria facilitate prey retention by the pitcher plant Darlingtonia californica.

    PubMed

    Armitage, David W

    2016-11-01

    Bacteria are hypothesized to provide a variety of beneficial functions to plants. Many carnivorous pitcher plants, for example, rely on bacteria for digestion of captured prey. This bacterial community may also be responsible for the low surface tensions commonly observed in pitcher plant digestive fluids, which might facilitate prey capture. I tested this hypothesis by comparing the physical properties of natural pitcher fluid from the pitcher plant Darlingtonia californica and cultured 'artificial' pitcher fluids and tested these fluids' prey retention capabilities. I found that cultures of pitcher leaves' bacterial communities had similar physical properties to raw pitcher fluids. These properties facilitated the retention of insects by both fluids and hint at a previously undescribed class of plant-microbe interaction.

  16. Influence of poisoned prey on foraging behavior of ferruginous hawks

    USGS Publications Warehouse

    Vyas, Nimish B.; Kuncir, Frank; Clinton, Criss C.

    2017-01-01

    We recorded 19 visits by ferruginous hawks (Buteo regalis) over 6 d at two black–tailed prairie dog (Cynomys ludovicianus) subcolonies poisoned with the rodenticide Rozol® Prairie Dog Bait (0.005% chlorophacinone active ingredient) and at an adjacent untreated subcolony. Before Rozol® application ferruginous hawks foraged in the untreated and treated subcolonies but after Rozol® application predation by ferruginous hawks was only observed in the treated subcolonies. We suggest that ferruginous hawks' preference for hunting in the treated subcolonies after Rozol® application was influenced by the availability of easy-to-capture prey, presumably due to Rozol® poisoning. The energetically beneficial behavior of favoring substandard prey may increase raptor encounters with rodenticide exposed animals if prey vulnerability has resulted from poisoning.

  17. How sailfish use their bills to capture schooling prey.

    PubMed

    Domenici, P; Wilson, A D M; Kurvers, R H J M; Marras, S; Herbert-Read, J E; Steffensen, J F; Krause, S; Viblanc, P E; Couillaud, P; Krause, J

    2014-06-07

    The istiophorid family of billfishes is characterized by an extended rostrum or 'bill'. While various functions (e.g. foraging and hydrodynamic benefits) have been proposed for this structure, until now no study has directly investigated the mechanisms by which billfishes use their rostrum to feed on prey. Here, we present the first unequivocal evidence of how the bill is used by Atlantic sailfish (Istiophorus albicans) to attack schooling sardines in the open ocean. Using high-speed video-analysis, we show that (i) sailfish manage to insert their bill into sardine schools without eliciting an evasive response and (ii) subsequently use their bill to either tap on individual prey targets or to slash through the school with powerful lateral motions characterized by one of the highest accelerations ever recorded in an aquatic vertebrate. Our results demonstrate that the combination of stealth and rapid motion make the sailfish bill an extremely effective feeding adaptation for capturing schooling prey.

  18. Predator personality structures prey communities and trophic cascades.

    PubMed

    Start, Denon; Gilbert, Benjamin

    2017-03-01

    Intraspecific variation is central to our understanding of evolution and population ecology, yet its consequences for community ecology are poorly understood. Animal personality - consistent individual differences in suites of behaviours - may be particularly important for trophic dynamics, where predator personality can determine activity rates and patterns of attack. We used mesocosms with aquatic food webs in which the top predator (dragonfly nymphs) varied in activity and subsequent attack rates on zooplankton, and tested the effects of predator personality. We found support for four hypotheses: (1) active predators disproportionately reduce the abundance of prey, (2) active predators select for predator-resistant prey species, (3) active predators strengthen trophic cascades (increase phytoplankton abundance) and (4) active predators are more likely to cannibalise one another, weakening all other trends when at high densities. These results suggest that intraspecific variation in predator personality is an important determinant of prey abundance, community composition and trophic cascades.

  19. Biomechanics (Communication arising): prey attack by a large theropod dinosaur.

    PubMed

    Frazzetta, T H; Kardong, Kenneth V

    2002-03-28

    Prey-capture strategies in carnivorous dinosaurs have been inferred from the biomechanical features of their tooth structure, the estimated bite force produced, and their diet. Rayfield et al. have used finite-element analysis (FEA) to investigate such structure-function relationships in Allosaurus fragilis, and have found that the skull was designed to bear more stress than could be generated by simple biting. They conclude that this large theropod dinosaur delivered a chop-and-slash 'hatchet' blow to its prey, which it approached with its mouth wide open before driving its upper tooth row downwards. We argue that this mode of predation is unlikely, and that the FEA results, which relate to an 'overengineered' skull, are better explained by the biomechanical demands of prey capture. Understanding the mechanics of predation is important to our knowledge of the feeding habits of carnivorous dinosaurs and for accurate reconstruction their lifestyles.

  20. Predator-prey oscillations can shift when diseases become endemic.

    PubMed

    Bate, Andrew M; Hilker, Frank M

    2013-01-07

    In epidemiology, knowing when a disease is endemic is important. This is usually done by finding the basic reproductive number, R(0), using equilibrium-based calculations. However, oscillatory dynamics are common in nature. Here, we model a disease with density dependent transmission in an oscillating predator-prey system. The condition for disease persistence in predator-prey cycles is based on the time-average density of the host and not the equilibrium density. Consequently, the time-averaged basic reproductive number R(0)¯ is what determines whether a disease is endemic, and not on the equilibrium-based basic reproductive number R(0)(*). These findings undermine any R(0) analysis based solely on steady states when predator-prey oscillations exist for density dependent diseases.

  1. Predatory fish select for coordinated collective motion in virtual prey.

    PubMed

    Ioannou, C C; Guttal, V; Couzin, I D

    2012-09-07

    Movement in animal groups is highly varied and ranges from seemingly disordered motion in swarms to coordinated aligned motion in flocks and schools. These social interactions are often thought to reduce risk from predators, despite a lack of direct evidence. We investigated risk-related selection for collective motion by allowing real predators (bluegill sunfish) to hunt mobile virtual prey. By fusing simulated and real animal behavior, we isolated predator effects while controlling for confounding factors. Prey with a tendency to be attracted toward, and to align direction of travel with, near neighbors tended to form mobile coordinated groups and were rarely attacked. These results demonstrate that collective motion could evolve as a response to predation, without prey being able to detect and respond to predators.

  2. IgE Immunotherapy Against Cancer

    PubMed Central

    Leoh, Lai Sum

    2015-01-01

    The success of antibody therapy in cancer is consistent with the ability of these molecules to activate immune responses against tumors. Experience in clinical applications, antibody design, and advancement in technology have enabled antibodies to be engineered with enhanced efficacy against cancer cells. This allows re-evaluation of current antibody approaches dominated by antibodies of the IgG class with a new light. Antibodies of the IgE class play a central role in allergic reactions and have many properties that may be advantageous for cancer therapy. IgE-based active and passive immunotherapeutic approaches have been shown to be effective in both in vitro and in vivo models of cancer, suggesting the potential use of these approaches in humans. Further studies on the anticancer efficacy and safety profile of these IgE-based approaches are warranted in preparation for translation toward clinical application. PMID:25553797

  3. A case of IgA nephropathy in three sisters with thin basement membrane disease.

    PubMed

    Yoshida, K; Suzuki, J; Suzuki, S; Kume, K; Suzuki, H; Hujiki, T

    1998-01-01

    IgA nephropathy associated with thin basement membrane disease is reported in a 9-year-old female. The diagnosis of IgA nephropathy was made by means of an immunofluorescence investigation, which showed generalized diffuse mesangial deposits. Thin basement membrane disease was identified by electron-microscopic investigations, which disclosed thinning of the basement membrane of several capillary loops and prominence of the lamina densa. Her father, elder sister and younger sister were also found to have hematuria and her sisters were diagnosed as having thin basement membrane disease by renal biopsy. Patients with IgA nephropathy have focal thinning of the glomerular basement membrane, but we consider that urinalysis of the family needs to be done for the diagnosis of familial thin basement membrane disease, when diffuse thinning of the glomerular basement membrane is detected in such patients.

  4. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces

    PubMed Central

    Clare, Elizabeth L; Holderied, Marc W

    2015-01-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an ‘acoustic shadow’ cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for ‘acoustic camouflage’ as an anti-predator defence mechanism. DOI: http://dx.doi.org/10.7554/eLife.07404.001 PMID:26327624

  5. Serological Profile of HSV-2 in STD Patients: Evaluation of Diagnostic Utility of HSV-2 IgM and IgG Detection

    PubMed Central

    Rashetha; Sucilathangam, G.; Cinthujah, B.; Revathy, C.

    2014-01-01

    Background and Objectives:The present study was undertaken to determine Herpes Simplex Virus-2 seroprevalence in sexually active adults aged 20-49 and to investigate the correlation with sociodemographic characteristics and to find its association with other sexually transmitted diseases especially HIV and also to assess the proportion of primary and reactivated HSV-2 cases. Materials and Methods:This prospective study was carried out for a period of six months in a tertiary care hospital. Serum samples were taken from 91 patients attending the out Patient clinic of the Department of Venereology. The serological testing for HSV-2 was performed on all the specimens by using Euroimmun anti-HSV2 (gG2) IgM ELISA and IgG ELISA. Results: Out of the 91 STD patients in the study group, 18 males (34.62%) and 14 females (36.84%) tested positive for HSV-2 antibodies. Seropositivity rate is 35.16%. More number of HSV-2 positive cases were seen among males, older age, rural residence, low socioeconomic status, single marital status, irregular condom usage during the sexual intercourses with new partners and with higher number of sexual partners during lifetime. HSV-2 IgM alone was positive in three cases, HSV-2 IgG alone was positive in 26 cases and three had a positive HSV-2 IgM and IgG result. Addition of IgM testing increased rate of detecting seroconversion, 31.87%, when only IgG ELISA was used, to 35.16 % patients when IgM test was added. In the study group four cases tested positive for VDRL, and one of them was a known positive case. Among the 55 HIV positive cases in the study group, HSV 2 was positive in 17 cases and among the 36 HIV negative cases HSV 2 was positive in 15 cases. (30.91% and 47.22%).Though the number of HIV cases were high, HSV 2 positivity among them was statistically not significant. Conclusion:The purpose of screening for HSV-2 is not only to identify seropositivity, but to help seropositive people identify symptoms and protect themselves from

  6. Independence Day for IgA.

    PubMed

    Macpherson, Andrew J; McCoy, Kathy D

    2015-09-15

    IgA is induced through T-cell-dependent and -independent pathways. In this issue, Bunker et al. (2015) now show that the T-cell-independent pathway is sufficient to coat most small intestinal microbes specifically, and Fransen et al. (2015) find that IgA coating promotes uptake of microbes into Peyer's patches and drives further induction in a positive-feedback loop.

  7. Predator-prey interactions, flight initiation distance and brain size.

    PubMed

    Møller, A P; Erritzøe, J

    2014-01-01

    Prey avoid being eaten by assessing the risk posed by approaching predators and responding accordingly. Such an assessment may result in prey-predator communication and signalling, which entail further monitoring of the predator by prey. An early antipredator response may provide potential prey with a selective advantage, although this benefit comes at the cost of disturbance in terms of lost foraging opportunities and increased energy expenditure. Therefore, it may pay prey to assess approaching predators and determine the likelihood of attack before fleeing. Given that many approaching potential predators are detected visually, we hypothesized that species with relatively large eyes would be able to detect an approaching predator from afar. Furthermore, we hypothesized that monitoring of predators by potential prey relies on evaluation through information processing by the brain. Therefore, species with relatively larger brains for their body size should be better able to monitor the intentions of a predator, delay flight for longer and hence have shorter flight initiation distances than species with smaller brains. Indeed, flight initiation distances increased with relative eye size and decreased with relative brain size in a comparative study of 107 species of birds. In addition, flight initiation distance increased independently with size of the cerebellum, which plays a key role in motor control. These results are consistent with cognitive monitoring as an antipredator behaviour that does not result in the fastest possible, but rather the least expensive escape flights. Therefore, antipredator behaviour may have coevolved with the size of sense organs, brains and compartments of the brain involved in responses to risk of predation.

  8. IgG4-related kidney disease--A review.

    PubMed

    Pradhan, Dinesh; Pattnaik, Niharika; Silowash, Russell; Mohanty, Sambit Kumar

    2015-10-01

    IgG4-related disease (IgG4-RD) is a recently recognized systemic autoimmune disorder characterized by high levels of serum IgG4 and dense infiltration of IgG4-positive plasma cells in multiple organs. The condition was first described as a disease of the pancreas, and has since been recognized in various organ systems including the kidneys. IgG4 related kidney disease (IgG4-RKD) signifies any form of renal involvement by IgG4-RD. The most common renal involvement by IgG4-RD is tubulointerstitial nephritis. Glomerular disease, in particular membranous glomerulonephritis, may also be seen. Other co-existent glomerular diseases such as IgA nephropathy, membranoproliferative glomerulonephritis, and mesangioproliferative immune complex glomerulonephritis may be identified. IgG4-related plasma cell arteritis has also been noted in the kidney. As with IgG4-RD in general, IgG4 related kidney disease (IgG4-RKD) usually occurs in middle-aged to elderly men. Common findings in IgG4-RKD are plasma cell-rich interstitial inflammatory infiltrate either in a focal or diffuse pattern with increased IgG4+ plasma cells, expansile swirling interstitial fibrosis, high levels of serum IgG and IgG4, hypocomplementemia, high serum IgE levels and/or peripheral blood eosinophilia. By immunofluorescence, most of the cases show IgG4 dominant tubular basement membrane immune complex deposits. Similar to IgG4-RD, IgG4-RKD often shows a rapid response to steroid therapy. In this review, we discuss the current knowledge on IgG4-RKD and its clinical relevance.

  9. Laboratory investigations of the effects of predator sex and size on prey selection by the Asian crab, Hemigrapsus sanguineus.

    PubMed

    Brousseau, D J.; Filipowicz, A; Baglivo, J A.

    2001-07-30

    Laboratory studies have shown that the nonindigenous Asian shore crab, Hemigrapsus sanguineus, readily consumes three species of commercial bivalves: blue mussels, Mytilus edulis, soft-shell clams, Mya arenaria, and oysters, Crassostrea virginica. Although crabs can eat bivalves of a wide size range, they preferred the smaller prey (Prey critical size limits exist for M. edulis and C. virginica, but not M. arenaria, possibly because of differences in shell characteristics among the three species. Crabs preferred M. arenaria over both M. edulis and C. virginica, and M. edulis was strongly preferred over C. virginica in pairwise comparison tests. Experiments to determine feeding rates on mussels showed that H. sanguineus can consume large numbers of mussels daily (12.7+/-11.6 mussels day(-1); sexes pooled; N=59). Mussel consumption rates increased with size of the predator and male crabs consumed more mussels than did similarly sized female crabs. The high densities of Hemigrapsus that occur in the wild, their effectiveness as predators of juvenile bivalves and their large appetites suggest an important role for these predators in restructuring the prey communities in habitats into which they have been introduced.

  10. Host plant mediates foraging behavior and mutual interference among adult Stethorus gilvifrons (Coleoptera: Coccinellidae) preying on Tetranychus urticae (Acari: Tetranychidae).

    PubMed

    Bayoumy, Mohamed H; Osman, Mohamed A; Michaud, J P

    2014-10-01

    Physical plant characteristics can influence predator foraging and their behavioral responses to each other. This study examined the searching efficiency and functional response of adult female Stethorus gilvifrons Mulsant foraging for Tetranychus urticae Koch (Acari: Tetranychidae) on castor bean, common bean, and cucumber leaves. Experiments conducted on leaf discs in arenas for 12 h revealed a type II functional response for S. gilvifrons on all host plants. Per capita searching efficiency and killing power decreased with increasing predator density on all plants, but most notably on common bean, the plant with the highest prey consumption rates, due to greater mutual interference. Attack rates were highest on common bean and lowest on castor bean, whereas handling times were shortest on common bean and longest on cucumber, such that the daily predation rate was maximal on common bean. Host plant interacted with predator and prey densities to affect searching efficiency and functional response, the differences in mite consumption among host plants increasing with predator and prey densities. The waxy layers of castor bean leaves and high trichome counts of cucumber leaves appeared to reduce predator foraging efficiency. Thus, the efficacy of S. gilvifrons against T. urticae is likely to be greatest on plants such as Phaeseolus vulgaris L. that have relatively smooth leaves.

  11. Poor response of initial steroid therapy for IgG4-related sclerosing cholangitis with multiple organs affected

    PubMed Central

    Liu, Wei; Chen, Weijie; He, Xiaodong; Qu, Qiang; Hong, Tao; Li, Binglu

    2017-01-01

    Abstract IgG4-related sclerosing cholangitis (IgG4-SC) is a rare biliary manifestation in which many other organs might be affected. The purpose of our study was to investigate the different clinical characteristics and initial steroid response between IgG4-SC patients with and without other organs affected. A series of patients with IgG4-SC in the period from January 2006 to December 2015 at our hospital were included. The pancreas and major salivary glands were screened, and the initial corticosteroid therapy was given. Clinical information was collected and analyzed including demographics, clinical presentation, IgG4 serology, imaging features, and treatment outcomes. The study identified 72 IgG4-SC patients, including 60 males and 12 females. The mean age was 59.8 years old. Among these IgG4-SC patients, 10 patients had only bile duct involved, 42 patients had 2 organs involved and 20 patients had multiple organs involved. In patients with multiple organs involved, more complaints were given (mean 2.9 kinds), higher serum IgG4 levels were found (23458 ± 19402.7 mg/L), and more stricture lesions of biliary tract were shown. All 72 patients exhibited a disease response within 4 to 6 weeks of starting steroids. The remission rate in the multiple lesions group was lower (60%), and the recurrence rate is higher (83.3%). The relapse-free survival was 20.0 months in the single lesion group, which is longer than that in the multiple lesions group (3.1 months, P < 0.05). The IgG4-SC patients with multiple organs affected had more complaints, higher serum IgG4 levels, and poor response to initial steroids. PMID:28328835

  12. The stabilizing effects of genetic diversity on predator-prey dynamics.

    PubMed

    Steiner, Christopher F; Masse, Jordan

    2013-01-01

    Heterogeneity among prey in their susceptibility to predation is a potentially important stabilizer of predator-prey interactions, reducing the magnitude of population oscillations and enhancing total prey population abundance. When microevolutionary responses of prey populations occur at time scales comparable to population dynamics, adaptive responses in prey defense can, in theory, stabilize predator-prey dynamics and reduce top-down effects on prey abundance. While experiments have tested these predictions, less explored are the consequences of the evolution of prey phenotypes that can persist in both vulnerable and invulnerable classes. We tested this experimentally using a laboratory aquatic system composed of the rotifer Brachionus calyciflorus as a predator and the prey Synura petersenii, a colony-forming alga that exhibits genetic variation in its propensity to form colonies and colony size (larger colonies are a defense against predators). Prey populations of either low initial genetic diversity and low adaptive capacity or high initial genetic diversity and high adaptive capacity were crossed with predator presence and absence. Dynamics measured over the last 127 days of the 167-day experiment revealed no effects of initial prey genetic diversity on the average abundance or temporal variability of predator populations. However, genetic diversity and predator presence/absence interactively affected prey population abundance and stability; diversity of prey had no effects in the absence of predators but stabilized dynamics and increased total prey abundance in the presence of predators. The size structure of the genetically diverse prey populations diverged from single strain populations in the presence of predators, showing increases in colony size and in the relative abundance of cells found in colonies. Our work sheds light on the adaptive value of colony formation and supports the general view that genetic diversity and intraspecific trait variation of

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

    USGS Publications Warehouse

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

    2008-01-01

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

  14. Large orb-webs adapted to maximise total biomass not rare, large prey.

    PubMed

    Harmer, Aaron M T; Clausen, Philip D; Wroe, Stephen; Madin, Joshua S

    2015-09-16

    Spider orb-webs are the ultimate anti-ballistic devices, capable of dissipating the relatively massive kinetic energy of flying prey. Increased web size and prey stopping capacity have co-evolved in a number orb-web taxa, but the selective forces driving web size and performance increases are under debate. The rare, large prey hypothesis maintains that the energetic benefits of rare, very large prey are so much greater than the gains from smaller, more common prey that smaller prey are irrelevant for reproduction. Here, we integrate biophysical and ecological data and models to test a major prediction of the rare, large prey hypothesis, that selection should favour webs with increased stopping capacity and that large prey should comprise a significant proportion of prey stopped by a web. We find that larger webs indeed have a greater capacity to stop large prey. However, based on prey ecology, we also find that these large prey make up a tiny fraction of the total biomass (=energy) potentially captured. We conclude that large webs are adapted to stop more total biomass, and that the capacity to stop rare, but very large, prey is an incidental consequence of the longer radial silks that scale with web size.

  15. Increased olfactory search costs change foraging behaviour in an alien mustelid: a precursor to prey switching?

    PubMed

    Price, Catherine J; Banks, Peter B

    2016-09-01

    If generalist predators are to hunt efficiently, they must track the changing costs and benefits of multiple prey types. Decisions to switch from hunting preferred prey to alternate prey have been assumed to be driven by decreasing availability of preferred prey, with less regard for accessibility of alternate prey. Olfactory cues from prey provide information about prey availability and its location, and are exploited by many predators to reduce search costs. We show that stoats Mustela erminea, an alien olfactory predator in New Zealand, are sensitive to the search costs of hunting both their preferred rodent prey (mice) and a less desirable alternate prey (locust). We manipulated search costs for stoats using a novel form of olfactory camouflage of both prey, and found that stoats altered their foraging strategy depending on whether mice were camouflaged or conspicuous, but only when locusts were also camouflaged. Stoats gave up foraging four times more often when both prey were camouflaged, compared to when mice were conspicuous and locusts camouflaged. There were no differences in the foraging strategies used to hunt camouflaged or conspicuous mice when locusts were easy to find. Consequently, camouflaged mice survived longer than conspicuous mice when locusts were hard to find, but not when locusts were easy to find. Our results demonstrate that predators can integrate search costs from multiple prey types when making foraging decisions. Manipulating olfactory search costs to alter foraging strategies offers new methods for understanding the factors that foreshadow prey switching.

  16. Stomach fullness modulates prey size choice in the frillfin goby, Bathygobius soporator.

    PubMed

    Tomida, Leonardo; Lee, James T; Barreto, Rodrigo E

    2012-10-01

    Behaviours related to foraging and feeding in predator-prey systems are fundamental to our understanding of food webs. From the perspective of a predator, the selection of prey size depends upon a number of factors including prey vulnerability, prey size, and the predator's motivation to eat. Thus, feeding motivation and prey visual cues are supposed to influence predator decisions and it is predicted that prey selection by visual cues is modulated by the predator's stomach fullness prior to attacking a prey. This study was conducted using an animal model from the rocky shores ecosystem, a predatory fish, the frillfin goby Bathygobius soporator, and a benthic prey, the mottled shore crab Pachygrapsus transversus. Our results demonstrate that frillfin gobies are capable of visually evaluating prey size and that the size evaluation process is modulated by the level of stomach fullness. Predators with an empty stomach (0% fullness) attacked prey that was larger than the predicted optimal size. Partially satiated predators (50% stomach fullness) selected prey close to the optimal size, while fully satiated predators (100% stomach fullness) showed no preference for size. This finding indicates an integrative response of the predator that depends on the input of both internal and external sensory information when choosing prey. Predator perceptions of visual cues (prey size) and stomach fullness modulate foraging decisions. As a result, a flexible feeding behaviour emerges, evidencing a clearly adaptive response in line with optimal foraging theory predictions.

  17. An Eco-epidemiological System with Infected Prey and Predator subject to the weak Allee effect.

    PubMed

    Sasmal, Sourav Kumar; Chattopadhyay, Joydev

    2013-10-24

    In this article, we propose a general prey-predator model with disease in prey and predator subject to the weak Allee effects. We make the following assumptions: (i) infected prey competes for resources but does not contribute to reproduction; and (ii) in comparison to the consumption of the susceptible prey, consumption of infected prey would contribute less or negatively to the growth of predator. Based on these assumptions, we provide basic dynamic properties for the full model and corresponding submodels with and without the Allee effects. By comparing the disease free submodels (susceptible prey-predator model) with and without the Allee effects, we conclude that the Allee effects can create or destroy the interior attractors. This enables us to obtain the complete dynamics of the full model and conclude that the model has only one attractor (only susceptible prey survives or susceptible-infected coexist), or two attractors (bi-stability with only susceptible prey and susceptible prey-predator coexist or susceptible prey-infected prey coexists and susceptible prey-predator coexist). This model does not support the coexistence of susceptible-infected-predator, which is caused by the assumption that infected population contributes less or are harmful to the growth of predator in comparison to the consumption of susceptible prey.

  18. Porcine allergy and IgE.

    PubMed

    Rupa, Prithy; Schmied, Julie; Wilkie, Bruce N

    2009-11-15

    Anaphylaxis was reported in 1963 in pigs experimentally sensitized with ovalbumin and was subsequently associated indirectly with IgE-related antibodies by functional assays to confirm heat-labile passive cutaneous anaphylaxis (PCA), reverse passive anaphylaxis (RPA) and Prausnitz-Küstner (PK) reactions to this and other allergens. The immunoglobulin mediating immediate hypersensitivity could be cross-adsorbed with anti-human IgE. Porcine IgE epsilon chain has been cloned and sequenced. Rabbit anti-pig IgE has been described by two groups, as has cross reactivity with pig IgE of various heterologous polyclonal and monoclonal anti-IgEs. Pigs develop transient post-weaning food allergy to soy allergens which can be prevented by pre-weaning feeding of soy proteins in sufficient quantity. Natural hypersensitivity also occurs to nematodes. Recently, experimental allergy has been induced in outbred pigs to peanut and to egg allergens which manifest as respiratory, cutaneous and enteric signs similar to those of human food allergy. These models are platforms for comparative allergy research as realistic alternatives to use of inbred mice or humans for investigation of pathogenesis, prophylaxis and therapy.

  19. IgE antibodies in toxoplasmosis.

    PubMed

    Matowicka-Karna, Joanna; Kemona, Halina

    2014-05-15

    Toxoplasmosis is a worldwide infection caused by the intracellular parasite Toxoplasma gondii. At least a third of the world human population is infected with the parasite, making it one of the most successful parasitic infections. Primary maternal infection may cause health-threatening sequelae for the fetus, or even cause death of the uterus. Reactivation of a latent infection in immune deficiency conditions such as AIDS and organ transplantation can cause fatal toxoplasmic encephalitis. Toxoplasmosis is a major cause of chorioretinitis, especially in individuals with impaired immune systems. In the acute phase, directly after invading the body, T. gondii begins to multiply rapidly. In the majority of cases acquired toxoplasmosis is asymptomatic. In the second week of infection, specific IgM antibodies are present in the blood. IgE antibodies appear at the same time, slightly preceding specific IgA antibodies. The concentration of IgE can be one of the parameters used for diagnosing an infection with T. gondii. Laboratory diagnosis, i.e. IgE and serologic assays, plays the main role in the diagnosis of congenital infection and assists in the confirmatory diagnosis of toxoplasmic encephalitis and ocular toxoplasmosis. This article is a review of IgE in toxoplasmosis.

  20. Oscillatory behavior in a lattice prey-predator system.

    PubMed

    Lipowski, A

    1999-11-01

    Using Monte Carlo simulations we study a lattice model of a prey-predator system. We show that in the three-dimensional model populations of preys and predators exhibit coherent periodic oscillations but such a behavior is absent in lower-dimensional models. Finite-size analysis indicate that amplitude of these oscillations is finite even in the thermodynamic limit. This is an example of a microscopic model with stochastic dynamics which exhibits oscillatory behavior without any external driving force. We suggest that oscillations in our model are induced by some kind of stochastic resonance.

  1. Stability of a Prey-Predator Model with Behavior Changes

    NASA Astrophysics Data System (ADS)

    Wang, Wendi

    2010-04-01

    A prey-predator system with hawk and dove behavior changes is studied, which allows the same time scale for population growth and individual behavior changes. Through stability analysis, we find that the four patterns in dynamical behaviors persist when the restriction is removed that the time scale of the behavior changes is much faster than that of population growth. The patterns include the bistability of an eqUilibrium of predator survival and an equilibrium of predator extinction, the coexistence of two stable equilibria of predator survival, a monostable equilibrium that describes the coexistence of prey and predators, and the extinction of predators for all positive initial values.

  2. Bogdanov-Takens bifurcation in a predator-prey model

    NASA Astrophysics Data System (ADS)

    Liu, Zhihua; Magal, Pierre; Xiao, Dongmei

    2016-12-01

    In this paper, we investigate a class of predator-prey model with age structure and discuss whether the model can undergo Bogdanov-Takens bifurcation. The analysis is based on the normal form theory and the center manifold theory for semilinear equations with non-dense domain combined with integrated semigroup theory. Qualitative analysis indicates that there exist some parameter values such that this predator-prey model has an unique positive equilibrium which is Bogdanov-Takens singularity. Moreover, it is shown that under suitable small perturbation, the system undergoes the Bogdanov-Takens bifurcation in a small neighborhood of this positive equilibrium.

  3. Predator-prey quasicycles from a path-integral formalism.

    PubMed

    Butler, Thomas; Reynolds, David

    2009-03-01

    The existence of beyond mean-field quasicycle oscillations in a simple spatial model of predator-prey interactions is derived from a path-integral formalism. The results agree substantially with those obtained from analysis of similar models using system size expansions of the master equation. In all of these analyses, the discrete nature of predator-prey populations and finite-size effects lead to persistent oscillations in time, but spatial patterns fail to form. The path-integral formalism goes beyond mean-field theory and provides a focus on individual realizations of the stochastic time evolution of population not captured in the standard master-equation approach.

  4. On a predator-prey system of Gause type.

    PubMed

    Hasík, Karel

    2010-01-01

    In this paper a Gause type model of interactions between predator and prey population is considered. We deal with the sufficient condition due to Kuang and Freedman in the generalized form including a kind of weight function. In a previous paper we proved that the existence of such weight function implies the uniqueness of limit cycle. In the present paper we give a new condition equivalent to the existence of a weight function (Theorem 4.4). As a consequence of our result, it is shown that some simple qualitative properties of the trophic function and the prey isocline ensure the uniqueness of limit cycle.

  5. [IgG4-related disease that presented cranial, cervical, lumbar and sacral hypertrophic pachymeningitis associated with infundibulo-hypophysitis].

    PubMed

    Sakai, Toshiyuki; Kondo, Masahide; Yoshii, Shintaro; Tomimoto, Hidekazu

    2014-01-01

    We report a patient of 32-year-old female with central IgG4-related disease. She developed headache and visual disturbance. On examination, she revealed diabetes insipidus, retrobulbar neuritis, hyperreflexia and limb weakness. Her laboratory findings showed serum IgG4 elevation, pleocytosis and protein elevation in cerebrospinal fluid. Chest CT showed a nodular lesion in the S8 of the left lung. Cranial and spinal magnetic resonance images with gadolinium contrast material showed cranial, cervical and lumbosacral hypertrophic pachymeningitis associated with infundibulo-hypophysitis. Pathological findings of the left frontal dura mater revealed lymphoplasmacytic inflammatory cell infiltrate with dense fibrosis. IgG4 immunohistochemistry showed no IgG4 + plasma cells within the inflammatory infiltrate. During treatment with intravenous pulse methylprednisolone followed by oral prednisolone, she revealed recovery of visual acuity with improvement of hypertrophic pachymeningitis and normalization of serum IgG4. This is a first report of IgG4-related hypertrophic pachymeningitis which involved cranial, cervical and lumbosacral regions as well as infundibulo-hypophysitis in a young female.

  6. Lymphocyte surface IgD and IgM in Macaca monkeys: ontogeny, tissue distribution and occurrence on individual lymphocytes.

    PubMed Central

    Martin, L N; Leslie, G A

    1977-01-01

    A proportion of lymphocytes in blood, spleen and lymph nodes of nonhuman primates had immunoglobulin on their surfaces detectable by fluorescent antibody to human IgM and IgD. The majority of the individual lymphocytes having either IgM or IgD on their surfaces possessed both classes of immunoglobulin. Lymphocyte surface IgD was capped independently of surface IgM on the same cell when incubated at 37 degrees with anti-IgD. Lymphocytes with surface IgM and/or IgD were present in blood at birth and the percentages over the first 6 months of life were increased compared to older monkeys. A corona of cells faintly positive for both IgM and IgD was observed around germinal centres of both lymph nodes and spleen. Images Figure 1 Figure 2 PMID:412779

  7. Density of wild prey modulates lynx kill rates on free-ranging domestic sheep.

    PubMed

    Odden, John; Nilsen, Erlend B; Linnell, John D C

    2013-01-01

    Understanding the factors shaping the dynamics of carnivore-livestock conflicts is vital to facilitate large carnivore conservation in multi-use landscapes. We investigated how the density of their main wild prey, roe deer Capreolus capreolus, modulates individual Eurasian lynx Lynx lynx kill rates on free-ranging domestic sheep Ovis aries across a range of sheep and roe deer densities. Lynx kill rates on free-ranging domestic sheep were collected in south-eastern Norway from 1995 to 2011 along a gradient of different livestock and wild prey densities using VHF and GPS telemetry. We used zero-inflated negative binomial (ZINB) models including lynx sex, sheep density and an index of roe deer density as explanatory variables to model observed kill rates on sheep, and ranked the models based on their AICc values. The model including the effects of lynx sex and sheep density in the zero-inflation model and the effect of lynx sex and roe deer density in the negative binomial part received most support. Irrespective of sheep density and sex, we found the lowest sheep kill rates in areas with high densities of roe deer. As roe deer density decreased, males killed sheep at higher rates, and this pattern held for both high and low sheep densities. Similarly, females killed sheep at higher rates in areas with high densities of sheep and low densities of roe deer. However, when sheep densities were low females rarely killed sheep irrespective of roe deer density. Our quantification of depredation rates can be the first step towards establishing fairer compensation systems based on more accurate and area specific estimation of losses. This study demonstrates how we can use ecological theory to predict where losses of sheep will be greatest, and can be used to identify areas where mitigation measures are most likely to be needed.

  8. Wuchereria bancrofti filariasis in French Polynesia: age-specific patterns of microfilaremia, circulating antigen, and specific IgG and IgG4 responses according to transmission level.

    PubMed

    Chanteau, S; Glaziou, P; Plichart, C; Luquiaud, P; Moulia-Pelat, J P; N'Guyen, L; Cartel, J L

    1995-01-01

    The age-specific patterns of microfilaremia, Og4C3 antigenemia, anti-Brugia malayi IgG and IgG4 were assessed in 3 villages of low, medium and high transmission level for Wuchereria bancrofti filariasis. The prevalence rates for each of the 4 markers were clearly age dependent and their patterns strongly associated with the transmission level. The antigenemia prevalence rate was consistently higher than the microfilaremia prevalence rate, in all age groups. The prevalences of anti-B. malayi IgG and IgG4 responses were very similar and much higher than those of microfilaremia or antigenemia. Antibody responses reached the plateau at an earlier age and at a higher prevalence with increased intensity of transmission. For all the markers, the prevalence rates were significantly higher in males than in females.

  9. The effect of institutionalisation on elevated IgD and IgG levels in patients with Down's syndrome.

    PubMed

    McMillan, B C; Hanson, R P; Golubjatnikov, G; Sinha, S K

    1975-01-01

    Serum levels of IgA, IgD, IgE, IgG, IgM and levels of secretory IgA (S-IgA) in nasal specimens were quantitated by radial immunodiffusion in a group of forty-one institutionalised patients with Down's syndrome (all non-disjunctive trisomy-G karyotype) and their age, sex and race matched controls, consisting of institutionalised non-mongols and normal non-institutionalised subjects. Analysis of levels of all immunoglobulins by age and sex showed no differences within the populations. However, levels of IgA, IgD and IgG were found significantly higher in mongols than in the other two populations. The concentrations of IgM were lower in mongols than in other institutionalised retardates but higher than non-institutionalised normal controls. Levels of S-IgA or IgE were similar in all populations. It was shown that the length of institutionalisation was associated with elevated levels of IgA and depressed levels of IgM in mongols. However, elevated IgG levels in mongols did not appear to be associated with their length of institutionalisation. Similarly, elevated levels of IgD in mongols were not associated with their length of institutionalisation.

  10. “Auto-anti-IgE”: Naturally occurring IgG anti-IgE antibodies may inhibit allergen-induced basophil activation

    PubMed Central

    Chan, Yih-Chih; Ramadani, Faruk; Santos, Alexandra F.; Pillai, Prathap; Ohm-Laursen, Line; Harper, Clare E.; Fang, Cailong; Dodev, Tihomir S.; Wu, Shih-Ying; Ying, Sun; Corrigan, Christopher J.; Gould, Hannah J.

    2014-01-01

    Background Naturally occurring IgE-specific IgG autoantibodies have been identified in patients with asthma and other diseases, but their spectrum of functions is poorly understood. Objective Address the hypothesis that: (i) IgG anti-IgE autoantibodies are detectable in the serum of all subjects but elevated in asthmatic patients regardless of atopic status as compared with controls; (ii) some activate IgE-sensitized basophils; and (iii) some inhibit allergen-induced basophil activation. Methods IgE-specific IgG autoantibodies were detected and quantified in sera using ELISA. Sera were examined for their ability to activate IgE-sensitized human blood basophils in the presence and absence of allergen using a basophil activation test, and to inhibit allergen binding to specific IgE on a rat basophilic cell line stably expressing human FcεRI. Results IgG autoantibodies binding to both free and FcεRI-bound IgE were detected in patients with atopic and non-atopic asthma, as well as controls. While some were able to activate IgE-sensitised basophils, others inhibited allergen-induced basophil activation, at least partly by inhibiting binding of IgE to specific allergen. Conclusion Naturally occurring IgG anti-IgE autoantibodies may inhibit, as well as induce, basophil activation. They act in a manner distinct from therapeutic IgG anti-IgE antibodies such as omalizumab. They may at least partly explain why atopic subjects who make allergen-specific IgE never develop clinical symptoms, and why omalizumab therapy is of variable clinical benefit in severe atopic asthma. PMID:25112697

  11. IgE, IgG4 and IgA specific to Bet v 1-related food allergens do not predict oral allergy syndrome

    PubMed Central

    Guhsl, E E; Hofstetter, G; Lengger, N; Hemmer, W; Ebner, C; Fröschl, R; Bublin, M; Lupinek, C; Breiteneder, H; Radauer, C

    2015-01-01

    Background Birch pollen-associated plant food allergy is caused by Bet v 1-specific IgE, but presence of cross-reactive IgE to related allergens does not predict food allergy. The role of other immunoglobulin isotypes in the birch pollen-plant food syndrome has not been investigated in detail. Methods Bet v 1-sensitized birch pollen-allergic patients (n = 35) were diagnosed for food allergy by standardized interviews, skin prick tests, prick-to-prick tests and ImmunoCAP. Concentrations of allergen-specific IgE, IgG1, IgG4 and IgA to seven Bet v 1-related food allergens were determined by ELISA. Results Bet v 1, Cor a 1, Mal d 1 and Pru p 1 bound IgE from all and IgG4 and IgA from the majority of sera. Immunoglobulins to Gly m 4, Vig r 1 and Api g 1.01 were detected in <65% of the sera. No significant correlation was observed between plant food allergy and increased or reduced levels of IgE, IgG1, IgG4 or IgA specific to most Bet v 1-related allergens. Api g 1-specific IgE was significantly (P = 0.01) elevated in celeriac-allergic compared with celeriac-tolerant patients. Likewise, frequencies of IgE (71% vs 15%; P = 0.01) and IgA (86% vs 38%; P = 0.04) binding to Api g 1.01 were increased. Conclusion Measurements of allergen-specific immunoglobulins are not suitable for diagnosing Bet v 1-mediated plant food allergy to hazelnut and Rosaceae fruits. In contrast, IgE and IgA to the distantly related allergen Api g 1 correlate with allergy to celeriac. PMID:25327982

  12. Reference values of total serum IgE and their significance in the diagnosis of allergy in young European adults.

    PubMed

    Carosso, Aurelia; Bugiani, Massimiliano; Migliore, Enrica; Antò, Josep Maria; DeMarco, Roberto

    2007-01-01

    Allergic sensitization mediated by immunoglobulin E (IgE) is the basis of allergic diseases, and elevated total IgE, in spite of some well-known limitations, is frequently included as a diagnostic criterion for allergic diseases. The reference value of total IgE (IgE-t) in the literature (1.5-144 kU/l) was established almost 2 decades ago. The aim of this study was to establish IgE-t reference values, establishing an updated cutoff value able to identify atopic subjects, defined as a positive CAP-radioallergosorbent test to at least one of a panel of common allergens, among young European adults. The study included 6,670 subjects from 10 Western European countries within the framework of the European Community Respiratory Health Survey II. IgE-t and specific IgE (IgE-s) were measured for the main inhalant allergens; IgE-s in class 0 for all allergens (66.2%) characterized non-atopy. The reference values were estimated by means of linear regression using a 50% random subsample of non-atopic subjects. Two non-atopic subsamples were examined so that one subsample could be used to establish reference IgE-t values, and these values were compared to those in the second non-atopic subsample to validate the findings. Sensitivity and specificity for atopy were assessed on the other 50% of non-atopic and on all atopic subjects. The 95th percentile of IgE-t reference values in non-smokers was 148 kU/l in women and 169 kU/l in men, while it was 194 and 220 kU/l in female and male smokers, respectively: serum IgE-t above the 95th percentile identifies <32% and above the 99th percentile <20% of atopic adults (low sensitivity), but a serum IgE-t below the 95th percentile identifies >90% and below the 99th percentile identifies >95% of non-atopic adults (good specificity). Due to the adequate specificity, IgE-t values exceeding the normal limits confirm a suspected atopic status; however, because of the low sensitivity, values below the cutoff seem not to exclude an atopic status

  13. Operations of the International GPS Geodynamics Service (IGS)

    NASA Technical Reports Server (NTRS)

    Beutler, G.; Neilan, R.; Mueller, I.

    1993-01-01

    This paper focuses on the operations, organization, and interfaces of the International GPS Geodynamics Service (IGS) which is expected to contribute to geodesy for many years to come. It briefly summarizes the history of the IGS, reports on IGS '92 campaign activities, and describes the current IGS terms of reference and proposal status.

  14. Predator-induced changes of female mating preferences: innate and experiential effects

    PubMed Central

    2011-01-01

    Background In many species males face a higher predation risk than females because males display elaborate traits that evolved under sexual selection, which may attract not only females but also predators. Females are, therefore, predicted to avoid such conspicuous males under predation risk. The present study was designed to investigate predator-induced changes of female mating preferences in Atlantic mollies (Poecilia mexicana). Males of this species show a pronounced polymorphism in body size and coloration, and females prefer large, colorful males in the absence of predators. Results In dichotomous choice tests predator-naïve (lab-reared) females altered their initial preference for larger males in the presence of the cichlid Cichlasoma salvini, a natural predator of P. mexicana, and preferred small males instead. This effect was considerably weaker when females were confronted visually with the non-piscivorous cichlid Vieja bifasciata or the introduced non-piscivorous Nile tilapia (Oreochromis niloticus). In contrast, predator experienced (wild-caught) females did not respond to the same extent to the presence of a predator, most likely due to a learned ability to evaluate their predators' motivation to prey. Conclusions Our study highlights that (a) predatory fish can have a profound influence on the expression of mating preferences of their prey (thus potentially affecting the strength of sexual selection), and females may alter their mate choice behavior strategically to reduce their own exposure to predators. (b) Prey species can evolve visual predator recognition mechanisms and alter their mate choice only when a natural predator is present. (c) Finally, experiential effects can play an important role, and prey species may learn to evaluate the motivational state of their predators. PMID:21726456

  15. [Determination of immunoglobulins IgG, IgM and IgA in maternal serum in patients with intrauterine growth retardation].

    PubMed

    Möller, U; Seewald, H J; Groh, A; Ader, B

    1987-01-01

    Immunoglobulin IgG, IgM, and IgA were analysed in maternal serum of 33 patients with intrauterine growth retardation and 30 patients without hypotrophic newborns. The estimations of the immunoglobulins were carried out by means of single radial immunodiffusion according to Mancini and coworkers. There were no significant differences between both groups of patients. Therefore IgG, IgM, and IgA are no additional parameters for estimation of the placental function of the 3rd trimester of pregnancy.

  16. Density-dependent prey mortality is determined by the spatial scale of predator foraging.

    PubMed

    McCarthy, Erin K; White, J Wilson

    2016-02-01

    Foraging theory predicts which prey patches predators should target. However, in most habitats, what constitutes a 'patch' and how prey density is calculated are subjective concepts and depend on the spatial scale at which the predator (or scientist) is observing. Moreover, the predator's 'foraging scale' affects prey population dynamics: predators should produce directly density-dependent (DDD) prey mortality at the foraging scale, but inversely density-dependent (IDD) mortality (safety-in-numbers) at smaller scales. We performed the first experimental test of these predictions using behavioral assays with guppies (Poecilia reticulata) feeding on bloodworm 'prey' patches. The guppy's foraging scale had already been estimated in a prior study. Our experimental results confirmed theoretical predictions: predation was IDD when prey were aggregated at a scale smaller than the foraging scale, but not when prey were aggregated at larger scales. These results could be used to predict outcomes of predator-prey interactions in continuous, non-discrete habitats in the field.

  17. Pros and cons of VP1-specific maternal IgG for the protection of Enterovirus 71 infection.

    PubMed

    Kim, Young-In; Song, Jae-Hyoung; Kwon, Bo-Eun; Kim, Ha-Neul; Seo, Min-Duk; Park, KwiSung; Lee, SangWon; Yeo, Sang-Gu; Kweon, Mi-Na; Ko, Hyun-Jeong; Chang, Sun-Young

    2015-11-27

    Enterovirus 71 (EV71) causes hand, foot, and mouth diseases and can result in severe neurological disorders when it infects the central nervous system. Thus, there is a need for the development of effective vaccines against EV71 infection. Here we report that viral capsid protein 1 (VP1), one of the main capsid proteins of EV71, efficiently elicited VP1-specific immunoglobulin G (IgG) in the serum of mice immunized with recombinant VP1. The VP1-specific IgG produced in female mice was efficiently transferred to their offspring, conferring protection against EV71 infection immediately after birth. VP1-specific antibody can neutralize EV71 infection and protect host cells. VP1-specific maternal IgG in offspring was maintained for over 6 months. However, the pre-existence of VP1-specific maternal IgG interfered with the production of VP1-specific IgG antibody secreting cells by active immunization in offspring. Therefore, although our results showed the potential for VP1-specific maternal IgG protection against EV71 in neonatal mice, other strategies must be developed to overcome the hindrance of maternal IgG in active immunization. In this study, we developed an effective and feasible animal model to evaluate the protective efficacy of humoral immunity against EV71 infection using a maternal immunity concept.

  18. IgG antibodies in patients with pemphigus vulgaris before and after diagnosing with immunofluorescence.

    PubMed

    Azimi, Hamideh; Majidi, Jafar; Estakhri, Rasul; Goldust, Mohamad

    2013-06-15

    Pemphigus is defined as a group of chronic self-immune vesicular diseases histologically recognized by inter-epidermic vesicles resulting from acantholysis. The aim of this study was to evaluate the precipitant and circulative IgG antibodies in patients with pemphigus vulgaris before and after treating with immunofluorescence. Sixty-two patients (34 females and 28 males) with clinically and pathologically confirmed P.V. were studied prospectively over a one year period of time during which direct and indirect immunofluorescent tests were performed before and after treatment. They had mild or moderate forms of disease. All patients received prednisolon 1-2 mg/kg/day and Azathioprine 2-3 mg/kg/day or methylpredisolon (1 g day(-1) for 4 days) and cyclophosphamide (500 mg/first day) pulse therapy due to general condition. Thirty- four females and 28 males enrolled, the mean age were 39.5 years (SD = 12.7). Before treatment, 10 and 52 cases were positive for skin depositing + or ++) and circulatory IgG (1/20 -1/60), respectively. Two to 3 month later, 37 were IgG positive with titers 1/20 to 1/160. The correlation between circulatory IgG before and after treatment was weakly positive (p = 0.05, r = 0.415). In the present study, treatment methods used for patients suffering from pemphigus vulgaris were not successful in significantly decreasing the circulative autoantibodies levels.

  19. IgA/IgM responses to tryptophan and tryptophan catabolites (TRYCATs) are differently associated with prenatal depression, physio-somatic symptoms at the end of term and premenstrual syndrome.

    PubMed

    Roomruangwong, Chutima; Kanchanatawan, Buranee; Sirivichayakul, Sunee; Anderson, George; Carvalho, André F; Duleu, Sebastien; Geffard, Michel; Maes, Michael

    2017-05-01

    There is some evidence that lowered tryptophan and an activated tryptophan catabolite (TRYCAT) pathway play a role in depression, somatoform disorder, and postpartum blues. The aim of this study is to delineate the associations between the TRYCAT pathway and premenstrual syndrome (PMS) and perinatal depressive and physio-somatic symptoms. We examine the associations between end of term serum IgM and IgA responses to tryptophan and 9 TRYCATs in relation to zinc, C-reactive protein (CRP), and haptoglobin and prenatal physio-somatic (previously known as psychosomatic) symptoms (fatigue, back pain, muscle pain, dyspepsia, obstipation) and prenatal and postnatal depression and anxiety symptoms as measured using the Edinburgh Postnatal Depression Scale (EPDS), Hamilton Depression Rating Scale (HAMD), and Spielberger's State Anxiety Inventory (STAI). We included pregnant females with (n = 24) and without depression (n = 25) and 24 non-pregnant females. There were no significant associations between the IgA/IgM responses to tryptophan and TRYCATs and prenatal and postnatal depression/anxiety symptoms, except for lowered IgA responses to anthranilic acid in prenatal depression. A large part of the variance in IgA responses to most TRYCATs was explained by PMS and haptoglobin (positively) and CRP (inversely) levels. The IgA responses to TRYCATs were significantly increased in PMS, in particular picolinic, anthranilic, xanthurenic and kynurenic acid, and 3OH-kynurenine. Variance (62.5%) in physio-somatic symptoms at the end of term was explained by PMS, previous depressions, zinc (inversely), CRP and haptoglobin (both positively), and the IgM responses to quinolinic acid (positively), anthranilic acid, and tryptophan (both negatively). The results suggest that mucosa-derived TRYCAT pathway activation is significantly associated with PMS, but not with perinatal depression/anxiety symptoms. Physio-somatic symptoms in pregnancy have an immune-inflammatory pathophysiology

  20. Immunochromatographic IgG/IgM Test for Rapid Diagnosis of Active Tuberculosis▿

    PubMed Central

    Ben-Selma, Walid; Harizi, Hedi; Boukadida, Jalel

    2011-01-01

    For rapid diagnosis and discrimination between active tuberculosis (TB) and other pulmonary diseases, we evaluated the clinical usefulness of detection of serum immunoglobulin IgG and IgM antibodies raised against mycobacterial 38-kDa, 16-kDa, and 6-kDa antigens by a commercial rapid immunochromatographic IgG/IgM test (Standard Diagnostics, South Korea) in 246 serum samples from three groups of patients: (i) 171 patients with active TB (128 with pulmonary TB [pTB] and 43 with extrapulmonary TB [epTB]), (ii) 73 patients with pulmonary non-TB diseases, and (iii) two leprosy patients. The sensitivities of IgG and IgM in patients with active TB (pTB and epTB) were 68.4% and 2.3%, respectively. IgG had the best performance characteristics, with sensitivities of 78.1% and 39.5% in sera from patients with active pTB and epTB, respectively, and a specificity of 100%. The sensitivities of IgM were poor and were similar for pTB and epTB (2.3%). In contrast, specificity was very elevated (100%). The combination of IgG with IgM did not improve its sensitivity. IgG-mediated responses against the mycobacterial 38-kDa, 16-kDa, and 6-kDa antigens might constitute a clinically useful tool for presumptive diagnosis and discrimination of active pTB from other pulmonary diseases. Moreover, based on its simplicity and rapidity of application, it could be a screening tool for active pTB in poorly e