The venom of predators should be under strong selection pressure because it is a costly substance and prey may potentially become resistant. Particularly in prey-specialized predators, venom should be selected for its high efficiency against the focal prey. Very effective venom paralysis has been observed in specialized predators, such as spiders preying on dangerous prey. Here, we compared the toxicity of the venoms of two prey-specialized species, araneophagous Palpimanus sp. and myrmecophagous Zodarion nitidum, and their related generalist species. We injected different venom concentrations into two prey types-the prey preferred by a specialist and an alternative prey-and observed the mortality and the paralysis of the prey within 24 h. We found that the venoms of specialists were far more potent towards the preferred prey than alternative prey. The venoms of generalists were similarly potent towards both prey types. In addition, we tested the efficacy of two venom fractions (smaller and larger than 10 kDa) in araneophagous Palpimanus sp. Compounds larger than 10 kDa paralyzed both prey types, but smaller compounds (<10 kDa) were effective only on preferred prey, suggesting the presence of prey-specific compounds in the latter fraction. Our results confirm that prey-specialized spiders possess highly specific venom that allows them to subdue dangerous prey.

• Klíčová slova
• Araneae, LD50, ecological niche, predator-prey interactions, specialization, toxicity, venom ecological function,
• MeSH
• druhová specificita MeSH
• ekosystém MeSH
• Formicidae MeSH
• Gryllidae MeSH
• LD50 MeSH
• molekulová hmotnost MeSH
• paralýza chemicky indukované   MeSH
• pavoučí jedy chemie   toxicita   MeSH
• pavouci chemie   MeSH
• predátorské chování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• pavoučí jedy MeSH

In specialized predators, a variety of adaptations have evolved to such a level of specificity that they allow very effective exploitation of focal prey. Venom is an essential adaptive trait of predatory venomous species, such as spiders, yet our knowledge of spider venom is incomplete. In agreement with the prey preference hypothesis, we expected that the venom of spider specialists should be more toxic to focal than to alternative prey, because it is composed of prey-specific toxins. Here we used spiders with three types of trophic specializations: specialists that were ant-eating, termite-eating and spider-eating. We compared the efficacy of prey capture of preferred and alternative prey (measured as paralysis latency) with that of related generalists and profiled the venom of the studied species using proteomic methods. We used 22 spider species: six myrmecophagous, two termitophagous, three araneophagous and 11 euryphagous generalist species belonging to different families. We found that ten of the eleven specialist species induced significantly shorter paralysis latency in preferred prey than in alternative prey. Generalists exhibited either similar efficiency on both prey types or slightly higher efficiency on preferred prey. Multivariate analysis of proteomic profiles (peptides and proteins) revealed significant differences between trophic specializations, particularly in peptides. Specialists appear to have venom composed of unique specific compounds as revealed by the multivariate ordination and indicator analysis. These components are likely prey-specific toxins.

• Klíčová slova
• Araneae, adaptation, capture efficacy, paralysis, specialization, venom composition,
• MeSH
• fyziologická adaptace MeSH
• pavoučí jedy MeSH
• pavouci * MeSH
• predátorské chování * MeSH
• proteomika MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• pavoučí jedy MeSH

During 2012-2014 up to 286 birds of the orders Falconiformes (5 species), Accipitriformes (11 species), and Strigiformes (7 species) were examined for trematodes and this represents the first detailed study in Slovakia. A total of 12 trematode species belonging to the families Diplostomidae, Cyathocotylidae, Strigeidae, and Opisthorchiidae were identified. Rare infections were found in falcons where only two species (40 %) and three of 85 examined birds (3.5 %) were infected with a low range of two to four worms of generalists Strigea falconis or Plagiorchis elegans. Contrary to that, ten accipitriformes species (90.9 %) and 63 of 156 bird individuals (40.4 %) were infected with nine flukes: Conodiplostomum perlatum, Conodiplostomum spathula, Neodiplostomum attenuatum, Neodiplostomum spathoides, Parastrigea flexilis, Strigea falconis, Strigea vandenbrokae, Paracoenogonimus ovatus, and Metorchis bilis. S. falconis and N. attenuatum were the most frequent, occurring in parallel in eight and four bird species, in numbers up to 575 and 224. The intensity of infection with other fluke species was low ranging from one to 13 worms. Three owl (Strigiformes) representatives (42.9 %) were exclusive hosts for Neodiplostomum canaliculatum and Strigea strigis, and the proportion of positive and dissected individual birds was 10:45 (22.2 %). Both trematodes occurred in two or three owl species. In conclusion, apparent dissimilarity of trematode load of three unrelated lines of falcons, eagles, and owls was revealed. The present study extends our knowledge on the composition of the trematode fauna in Slovakia as all species except S. falconis and P. elegans that represent new host and species records in Slovakia.

• Klíčová slova
• Accipitriformes, Falconiformes, Host specificity, Strigiformes, Trematoda,
• MeSH
• dravci parazitologie   MeSH
• Falconiformes parazitologie   MeSH
• hostitelská specificita MeSH
• infekce červy třídy Trematoda epidemiologie   parazitologie   veterinární   MeSH
• játra parazitologie   MeSH
• nemoci ptáků epidemiologie   parazitologie   MeSH
• parazitární nemoci střev epidemiologie   parazitologie   veterinární   MeSH
• parazitární nemoci u zvířat epidemiologie   parazitologie   MeSH
• střeva parazitologie   MeSH
• Stringiformes parazitologie   MeSH
• Trematoda izolace a purifikace   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Slovenská republika epidemiologie   MeSH

Predators are traditionally classified as generalists and specialists based on the presence of adaptations that increase efficiency of prey capture and consumption and selection of particular prey types. Nevertheless, empirical evidence comparing foraging efficiency between generalist and specialist carnivores is scarce. We compared the prey-capture and feeding efficiency in a generalist and a specialist (araneophagous) spider predator. By using two related species, the generalist Harpactea rubicunda (Dysderidae) and the specialist Nops cf. variabilis (Caponiidae), we evaluated their fundamental trophic niche by studying the acceptance of different prey. Then, we compared their predatory behavior, efficiency in capturing prey of varying sizes, feeding efficiency, and nutrient extraction. Nops accepted only spiders as prey, while Harpactea accepted all offered prey, confirming that Nops is stenophagous, while Harpactea is euryphagous. Further, Nops displayed more specialized (stereotyped) capture behavior than Harpactea, suggesting that Nops is a specialist, while Harpactea is a generalist. The specialist immobilized prey faster, overcame much larger prey, and gained more mass (due to feeding on larger prey) than the generalist. Both the specialist and the generalist spider extracted more proteins than lipids, but the extraction of macronutrients in the specialist was achieved mainly by consuming the prosoma of the focal prey. We show that the specialist has more efficient foraging strategy than the generalist.

• Klíčová slova
• Dangerous prey, Macronutrients, Predatory behavior, Prey size, Trophic niche,
• MeSH
• druhová specificita MeSH
• fyziologická adaptace MeSH
• fyziologie výživy zvířat * MeSH
• pavouci fyziologie   MeSH
• predátorské chování * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Biological divergence results from several mechanisms. Defensive mechanisms, such as Batesian mimicry, can cause reproductive isolation via temporal segregation in foraging activity, particularly, in species that closely associate with their model. This seems to be the case of ant-eating spiders, which can be inaccurate Batesian mimics of their prey. Here, we focused on Zodarion nitidum, which has two forms occurring in sympatry, black and yellow. Given the expected noticeable impact of their colour differences on the spiders' interactions with their potential predators and prey, we investigated whether these morphotypes have diverged in other aspects of their biology. We measured the two morphotypes' phenotypic resemblance to a mimetic model, tested whether they were protected from predators, investigated their circadian activity, surveyed the prey they hunted, modelled their distributions, performed crossing experiments and estimated their degree of genetic differentiation. We found that the black morphotype is ant-like, resembling Messor ants, and it was not distinguishable from their ant models by four potential predators. In contrast, the yellow morphotype seems to use predator avoidance as a defensive strategy. Additionally, the two morphotypes differ in their circadian activity, the yellow morphotype being nocturnal and the black one being diurnal. The two morphotypes hunt and associate with different ant prey and possess marked differences in venom composition. Finally, crossing trials showed complete pre-mating isolation between the two morphotypes, but there was no evidence of genetic (mitochondrial data) or environmental niche differentiation. We conclude that the two morphotypes show evidence of a deep differentiation in morphological, behavioural, physiological and ecological traits that evolved together as part of the spider's diverging lifestyles.

• Klíčová slova
• Zodarion, Araneae, biological divergence, myrmecophagy, reproductive isolation, specialization,
• MeSH
• mimikry * fyziologie   MeSH
• pavouci * fyziologie   MeSH
• predátorské chování fyziologie   MeSH
• reprodukční izolace MeSH
• sympatrie MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We consider a special form of the Gause model of interactions between predator and prey populations. Using the ideas of Cheng, we prove the uniqueness of the limit cycle for more general systems, satisfying some additional conditions. These include also a condition due to Kuang and Freedman. Moreover, in this paper it is shown that the similar generalization of Cheng's uniqueness proof by Conway and Smoller is not correct.

• MeSH
• biologické modely * MeSH
• hustota populace MeSH
• predátorské chování * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In this paper we consider one-predator-two-prey population dynamics described by a control system. We study and compare conditions for permanence of the system for three types of predator feeding behaviors: (i) specialized feeding on the more profitable prey type, (ii) generalized feeding on both prey types, and (iii) optimal foraging behavior. We show that the region of parameter space leading to permanence for optimal foraging behavior is smaller than that for specialized behavior, but larger than that for generalized behavior. This suggests that optimal foraging behavior of predators may promote coexistence in predator-prey systems. We also study the effects of the above three feeding behaviors on apparent competition between the two prey types.

• MeSH
• biologické modely MeSH
• populační dynamika MeSH
• predátorské chování * MeSH
• stravovací zvyklosti * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Hunting other predators is dangerous, as the tables can turn and the hunter may become the hunted. Specialized araneophagic (spider eating) predators have evolved intriguing hunting strategies that allow them to invade spiders' webs by adopting a stealthy approach or using aggressive mimicry. Here, we present a newly discovered, specialized hunting strategy of the araneophagic spider Poecilochroa senilis (Araneae: Gnaphosidae), which forces its way into the silk retreat of the potential spider prey and immobilizes it by swathing gluey silk onto its forelegs and mouthparts. Poecilochroa senilis has been reported from the nests of a several, often large, spider species in the Negev desert (Israel), suggesting specialization on spiders as prey. Nevertheless, in laboratory experiments, we found that P. senilis has a wider trophic niche, and fed readily on several small insect species. The specialized nest-invading attack was used more frequently with large spiders, and even small juvenile P. senilis were able to attack and subdue larger spiders. Our observations show that specific hunting tactics, like nest usurpation, allow specialized predators to overcome defences of dangerous prey.

• MeSH
• pavouci fyziologie   MeSH
• predátorské chování * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

1. Disruptive natural selection resulting from specialization on different hosts is recognized as one of the most important driving forces in the diversification of herbivores and parasites. It has been proposed that a similar mechanism could apply to carnivorous predators too, although the evidence is still lacking. 2. Here, we show that the differentiation of biotypes of specialized ant-eating spiders of the genus Zodarion has probably been induced by prey-shifting. We focused on two forms of one species Z. styliferum from the Iberian Peninsula that presumably represent ecological races. We conducted geographic, ecological, venom-oriented, reproductive and genetic divergence analysis among multiple populations collected at a number of sites across Portugal and Madeira. 3. Geographic analysis revealed that the two forms occur in mosaic sympatry. Each form was found to associate in nature with a different ant species in a different habitat. Specifically, the styliferum form hunted predominantly Messor ants, and the extraneum form hunted mainly Camponotus ants. Laboratory experiments revealed that the two forms exhibit a significant preference for attacking focal ants, demonstrating higher paralysis efficiency, and also show different venom composition. Cross-mating of the two forms was significantly less likely than between pairs of the same form, suggesting moderate assortative mating. Phylogenetic analyses indicate low genetic differentiation of the two forms and parallel-repeated evolution of biotypes. 4. Adaptive prey-shifting correlated with habitat preference are at present the most valid explanations for biotype formation in Zodarion. The speciation of ant-eating Zodarion spiders thus appears to follow a scenario similar to that of host-shifting in parasites and herbivores.

• MeSH
• ekosystém MeSH
• Formicidae MeSH
• fylogeneze MeSH
• molekulární sekvence - údaje MeSH
• pavoučí jedy analýza   MeSH
• pavouci genetika   fyziologie   MeSH
• potravní řetězec * MeSH
• predátorské chování MeSH
• respirační komplex IV genetika   MeSH
• rozmnožování MeSH
• sekvenční analýza DNA MeSH
• selekce (genetika) * MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• vznik druhů (genetika) * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Portugalsko MeSH
• Španělsko MeSH
• Názvy látek
• pavoučí jedy MeSH
• respirační komplex IV MeSH

Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies.

• MeSH
• biodiverzita MeSH
• brouci * MeSH
• hlemýždi * MeSH
• larva MeSH
• molekulární evoluce MeSH
• predátorské chování * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Řecko MeSH