Spider wasps of the genus Minagenia have evolved koinobiontism as a relatively rare life strategy within the widely diversified hymenopteran family Pompilidae. In this study, we evaluated several aspects of the parasitic strategy of the wasp Minagenia sp. (hereafter, Minagenia) - namely host specificity, ontogeny, and sex determination as a function of host size. We found that Minagenia is highly host specific, being associated only with the genus Lycosa from the family Lycosidae, namely Lycosa u-album (Mello-Leitão, 1938), Lycosa erythrognatha (Lucas, 1836) and Lycosa poliostoma (Koch, 1847) with a parasitism incidence of 18.9%, 15.8% and 12.5%, respectively. Both ecological and taxonomical host traits determine the host selection and sex allocation of Minagenia female wasps. Charnov's host-size model explains Minagenia's host-size-dependent sex ratio in combination with the effect of host development stage, host species, and host foraging strategy. We also found that the final instar larva of Minagenia induces behavioural changes in spider hosts. The manipulated spider builds a protective silk chamber as a shelter for parasitoid pupation. Our results suggest that host manipulation seems to be narrowly connected with koinobiont life style throughout Hymenoptera. This study provides new information about the host-parasitoid koinobiont life strategy among spider wasps, which probably arose convergently in distant taxonomical groups within Pompilidae.
- MeSH
- chování zvířat MeSH
- interakce hostitele a parazita MeSH
- larva fyziologie MeSH
- rozmnožování fyziologie MeSH
- sršňovití fyziologie MeSH
- stadia vývoje MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Locomotion is an important, fitness-related functional trait. Environment selects for type of locomotion and shapes the morphology of locomotion-related traits such as body size and appendages. In subterranean aquatic arthropods, these traits are subjected to multiple, at times opposing selection pressures. Darkness selects for enhanced mechano- and chemosensory systems and hence elongation of appendages. Conversely, water currents have been shown to favor short appendages. However, no study has addressed the variation in locomotion of invertebrates inhabiting cave streams and cave lakes, or questioned the relationship between species' morphology and locomotion. To fill this knowledge gap, we studied the interplay between habitat use, morphology and locomotion in amphipods of the subterranean genus Niphargus. Previous studies showed that lake and stream species differ in morphology. Namely, lake species are large, stout and long-legged, whereas stream species are small, slender and short-legged. We here compared locomotion mode and speed between three lake and five stream species. In addition, we tested whether morphology predicts locomotion. We found that the stream species lie on their body sides and move using slow crawling or tail-flipping. The species inhabiting lakes move comparably faster, and use a variety of locomotion modes. Noteworthy, one of the lake species almost exclusively moves in an upright or semi-upright position that resembles walking. Body size and relative length of appendages predict locomotion mode and speed in all species. We propose that integrating locomotion in the studies of subterranean species might improve our understanding of their morphological evolution.
- MeSH
- Amphipoda fyziologie MeSH
- chování zvířat MeSH
- druhová specificita MeSH
- ekosystém * MeSH
- lokomoce * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Once believed to be restricted only to endotherms (mammals and birds), several poikilothermic amniote lineages have recently been documented to possess long-term evolutionary stability in their sex chromosomes. However, many important lineages were not included in these tests. Previously, based on molecular evidence, we documented the homology of well-differentiated sex chromosomes among seven families of iguanas (Pleurodonta), with basilisks (Corytophanidae) being the only exception, as the tested genes linked to X, but missing on the Y chromosome, in other iguanas were autosomal or pseudoautosomal in basilisks. In this study, we test the homology of sex chromosomes in the remaining, previously unstudied iguana families (Hoplocercidae, Leiosauridae, Liolaemidae, Polychrotidae) and in the basilisk genus Corytophanes. Our results show that 12 currently recognized families of iguanas share X-specific gene content conserved from the common ancestor living in the Cretaceous period. However, the results in the genus Corytophanes indicate the loss of the ancestral differentiated sex chromosomes from the ancestor of basilisks. Our new data further confirm the extensive stability of sex chromosomes in iguanas, thus enabling molecular sexing based on the comparison of the number of X-specific genes by quantitative PCR (qPCR) in all but one family of this widely diversified clade.
- MeSH
- chromozom X genetika MeSH
- fylogeneze MeSH
- genová dávka genetika MeSH
- karyotyp MeSH
- kvantitativní polymerázová řetězová reakce veterinární MeSH
- leguáni genetika MeSH
- pohlavní chromozomy genetika MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Birds are usually considered the main predators shaping the evolution of aposematic signals and mimicry. Nevertheless, some lizards also represent predominately visually oriented predators, so they may also play an important role in the evolution of aposematism. Despite this fact, experimental evidence regarding the responses of lizards to aposematic prey is very poor compared to such evidence in birds. Lizards possess very similar sensory and cognitive abilities to those of birds and their response to aposematic prey may thus be affected by very similar processes. We investigated the reactions of a lizard, the Gran Canaria skink (Chalcides sexlineatus), to an aposematic prey and its artificial Batesian mimic. Further, we attempted to ascertain whether the lizard's food experience has any effect on its ability to recognise an artificial Batesian mimic, by using two groups of predators differing in their prior experience with the prey from which the mimic was fabricated. The red firebug (Pyrrhocoris apterus) was used as an aposematic model, and the Guyana spotted roach (Blaptica dubia) as the palatable prey from which the mimic was fabricated. The appearance of the roach was modified by a paper sticker placed on its back. The skinks showed a strong aversion towards the model firebug. They also avoided attacking the cockroaches with the firebug pattern sticker. This suggests that a visual rather than a chemical signal is responsible for this aversion. The protection provided by the firebug sticker was even effective when the skinks were familiar with unmodified cockroaches (previous food experience).
- MeSH
- druhová specificita MeSH
- hmyz fyziologie MeSH
- ještěři fyziologie MeSH
- mimikry fyziologie MeSH
- predátorské chování fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Differences in life histories are commonly exhibited within ecological communities, especially among species that display increased variations in body size and morphology and are phylogenetically distant. To examine the relationship between morphological dissimilarity and life history divergence, we investigated three morphologically distinct and distantly related species of freshwater amphipods that co-occur throughout the Danube lowlands - Gammarus balcanicus dacicus, Niphargus valachicus and Synurella ambulans - by collecting monthly samples during a one-year period. Results revealed that the studied species differ significantly with respect to fecundity, size at maturity, number of generations per year, duration and timing of the reproductive period and egg volume. Despite some overlap, each species possesses a unique combination of traits, supporting the hypothesis that life history variation within freshwater amphipod communities can reflect dissimilarities regarding body size, morphology and evolutionary relationships. However, it is not yet clear which of these factors has the most significant contribution to life history divergence.
- MeSH
- Amphipoda anatomie a histologie klasifikace růst a vývoj fyziologie MeSH
- fylogeneze MeSH
- rozmnožování MeSH
- sladká voda MeSH
- těhotenství MeSH
- velikost těla MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Rumunsko MeSH
Beetles of the subfamily Cetoniinae are distinct and well-known, yet their larval ontogeny, sexual size dimorphism and development remain unknown in most species. This group contains many species with large males with prominent secondary sexual structures, such as cephalic or pronotal horns and elongated forelimbs. The species studied here, Pachnoda marginata, belongs to those species without any obvious dimorphism, the males being almost indistinguishable from the females. In this paper we examine sexual dimorphism in body shape and size in this apparently 'non-dimorphic' species. We further investigate the larval development and proximate causes of sexual size dimorphism, in particular when and how the sexes diverge in their growth trajectories during ontogeny. We found that males are larger than females and that the sexes also differ in body shape - for example, males possess significantly longer forelimbs relative to body size than females. The male-biased sexual size dimorphism along with prolonged forelimbs suggests that sexual selection for larger males may not be limited merely to horned species of rose chafers. The dimorphism in size in P. marginata arises during the second larval instar and basically remains unchanged till maturity. In both sexes the maximum body mass as well as developmental time of particular larval instars were strongly correlated, but time spent in the pupal chamber was not related to previous growth and final body size. The correlation between developmental time and adult size was negative, which may be a reflection of differences in resource allocation or utilisation for growth and development among individuals.
- MeSH
- brouci růst a vývoj MeSH
- končetiny anatomie a histologie MeSH
- larva růst a vývoj MeSH
- sexuální faktory MeSH
- velikost těla fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Studies of parasite population dynamics in natural systems are crucial for our understanding of host-parasite coevolutionary processes. Some field studies have reported that host genotype frequencies in natural populations change over time according to parasite-driven negative frequency-dependent selection. However, the temporal patterns of parasite genotypes have rarely been investigated. Moreover, parasite-driven negative frequency-dependent selection is contingent on the existence of genetic specificity between hosts and parasites. In the present study, the population dynamics and host-genotype specificity of the ichthyosporean Caullerya mesnili, a common endoparasite of Daphnia water fleas, were analysed based on the observed sequence variation in the first internal transcribed spacer (ITS1) of the ribosomal DNA. The Daphnia population of lake Greifensee (Switzerland) was sampled and subjected to parasite screening and host genotyping during C. mesnili epidemics of four consecutive years. The ITS1 of wild-caught C. mesnili-infected Daphnia was sequenced using the 454 pyrosequencing platform. The relative frequencies of C. mesnili ITS1 sequences differed significantly among years: the most abundant C. mesnili ITS1 sequence decreased and rare sequences increased over the course of the study, a pattern consistent with negative frequency-dependent selection. However, only a weak signal of host-genotype specificity between C. mesnili and Daphnia genotypes was detected. Use of cutting edge genomic techniques will allow further investigation of the underlying micro-evolutionary relationships within the Daphnia-C. mesnili system.
- MeSH
- časové faktory MeSH
- Daphnia genetika parazitologie MeSH
- genotyp MeSH
- hostitelská specificita MeSH
- interakce hostitele a parazita genetika imunologie MeSH
- Mesomycetozoea genetika fyziologie MeSH
- mezerníky ribozomální DNA MeSH
- selekce (genetika) MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Trophic specialists are expected to possess adaptations that increase the efficiency of handling preferred prey. Such adaptations may constrain the ability to utilise alternative prey. Here we tested whether the ant-eating spider Euryopis episinoides possesses metabolic specialisations with increased efficiency in utilising preferred prey and decreased efficiency in utilising alternative prey. In addition, we investigated the contribution of genetic variation via maternal effects. We reared E. episinoides spiders from the first instar on two different diets, either ants (preferred prey) or fruit flies (alternative prey). Spider survival rate and increases in body mass were significantly higher on the ant diet. The total development time did not differ between diet groups, nor did the number of egg sacs per female or the incubation period. However, the number of eggs per egg sac and hatching success were higher on the ant diet. There was a genetic variation in several offspring traits. Our data support the hypothesis that stenophagous ant-eating E. episinoides have a metabolic specialisation on ant utilisation indicated by higher efficiency in utilising ants than fruit flies. While most individuals of E. episinoides were able to capture fruit flies, only very few spiders were able to develop and reproduce on a pure fruit fly diet, suggesting the existence of within-species genetic variation regarding the tolerance to alternative prey.
- MeSH
- Drosophila melanogaster fyziologie MeSH
- druhová specificita MeSH
- energetický metabolismus fyziologie MeSH
- Formicidae fyziologie MeSH
- ovum fyziologie MeSH
- pavouci růst a vývoj fyziologie MeSH
- predátorské chování fyziologie MeSH
- stravovací zvyklosti MeSH
- tělesná hmotnost MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The chemical defence of Heteroptera is primarily based on repellent secretions which signal the potential toxicity of the bug to its predators. We tested the aversive reactions of green lizards (Lacerta viridis) towards the major compounds of the defensive secretion of Graphosoma lineatum, specifically: (i) a mixture of three aldehydes: (E)-hex-2-enal, (E)-oct-2-enal, (E)-dec-2-enal; (ii) a mixture of these three aldehydes and tridecane; (iii) oxoaldehyde: (E)-4-oxohex-2-enal; (iv) secretion extracted from metathoracic scent glands of G. lineatum adults and (v) hexane as a non-polar solvent. All chemicals were presented on a palatable food (Tenebrio molitor larvae). The aversive reactions of the green lizards towards the mealworms were evaluated by observing the approach latencies, attack latencies and approach-attack intervals. The green lizards exhibited a strong aversive reaction to the mixture of three aldehydes. Tridecane reduced the aversive reaction to the aldehyde mixture. Oxoaldehyde caused the weakest, but still significant, aversive reaction. The secretion from whole metathoracic scent glands also clearly had an aversive effect on the green lizards. Moreover, when a living specimen of G. lineatum or Pyrrhocoris apterus (another aposematic red-and-black prey) was presented to the green lizards before the trials with the aldehyde mixture, the aversive effect of the mixture was enhanced. In conclusion, the mixture of three aldehydes had the strong aversive effect and could signal the potential toxicity of G. lineatum to the green lizards.
Several hypotheses have been put forward to explain the evolution of prey specificity (stenophagy). Yet little light has so far been shed on the process of evolution of stenophagy in carnivorous predators. We performed a detailed analysis of a variety of trophic adaptations in one species. Our aim was to determine whether a specific form of stenophagy, myrmecophagy, has evolved from euryphagy via parallel changes in several traits from pre-existing characters. For that purpose, we studied the trophic niche and morphological, behavioural, venomic and physiological adaptations in a euryphagous spider, Selamia reticulata. It is a species that is branching off earlier in phylogeny than stenophagous ant-eating spiders of the genus Zodarion (both Zodariidae). The natural diet was wide and included ants. Laboratory feeding trials revealed versatile prey capture strategies that are effective on ants and other prey types. The performance of spiders on two different diets - ants only and mixed insects - failed to reveal differences in most fitness components (survival and developmental rate). However, the weight increase was significantly higher in spiders on the mixed diet. As a result, females on a mixed diet had higher fecundity and oviposited earlier. No differences were found in incubation period, hatching success or spiderling size. S. reticulata possesses a more diverse venom composition than Zodarion. Its venom is more effective for the immobilisation of beetle larvae than of ants. Comparative analysis of morphological traits related to myrmecophagy in the family Zodariidae revealed that their apomorphic states appeared gradually along the phylogeny to derived prey-specialised genera. Our results suggest that myrmecophagy has evolved gradually from the ancestral euryphagous strategy by integrating a series of trophic traits.
- MeSH
- biologická evoluce MeSH
- dieta MeSH
- druhová specificita MeSH
- Formicidae MeSH
- fyziologická adaptace MeSH
- genetická zdatnost MeSH
- pavoučí jedy chemie MeSH
- pavouci anatomie a histologie chemie genetika fyziologie MeSH
- potravní řetězec MeSH
- predátorské chování MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- stárnutí MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
