• MeSH
• chování zvířat MeSH
• hustota populace MeSH
• predátorské chování MeSH
• psychologické modely MeSH
• pudové chování MeSH
• výběrové chování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

Insecticides usually present in low concentrations in streams are known to impair behaviour and development of non-target freshwater invertebrates. Moreover, there is growing awareness that the presence of natural stressors, such as predation risk may magnify the negative effects of pesticides. This is because perception of predation risk can by itself lead to changes on behaviour and physiology of prey species. To evaluate the potential combined effects of both stressors on freshwater detritivores we studied the behavioural and developmental responses of Chironomus riparius to chlorantraniliprole (CAP) exposure under predation risk. Also, we tested whether the presence of a shredder species would alter collector responses under stress. Trials were conducted using a simplified trophic chain: Alnus glutinosa leaves as food resource, the shredder Sericostoma vittatum and the collector C. riparius. CAP toxicity was thus tested under two conditions, presence/absence of the dragonfly predator Cordulegaster boltonii. CAP exposure decreased leaf decomposition. Despite the lack of significance for interactive effects, predation risk marginally modified shredder effect on leaf decomposition, decreasing this ecosystem process. Shredders presence increased leaf decomposition, but impaired chironomids performance, suggesting interspecific competition rather than facilitation. C. riparius growth rate was decreased independently by CAP exposure, presence of predator and shredder species. A marginal interaction between CAP and predation risk was observed regarding chironomids development. To better understand the effects of chemical pollution to natural freshwater populations, natural stressors and species interactions must be taken into consideration, since both vertical and horizontal species interactions play their role on response to stress.

• MeSH
• Chironomidae účinky léků   růst a vývoj   fyziologie   MeSH
• hmyz účinky léků   růst a vývoj   fyziologie   MeSH
• insekticidy toxicita   MeSH
• larva účinky léků   růst a vývoj   fyziologie   MeSH
• listy rostlin MeSH
• nymfa účinky léků   růst a vývoj   fyziologie   MeSH
• olše MeSH
• ortoaminobenzoáty toxicita   MeSH
• potravní řetězec * MeSH
• predátorské chování * MeSH
• stravovací zvyklosti účinky léků   MeSH
• vážky růst a vývoj   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

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.

• MeSH
• ekosystém MeSH
• Lynx fyziologie   psychologie   MeSH
• populační dynamika MeSH
• potravní řetězec * MeSH
• predátorské chování fyziologie   MeSH
• proporcionální rizikové modely MeSH
• roční období MeSH
• sexuální faktory MeSH
• stalking psychologie   MeSH
• věkové faktory MeSH
• velikost těla MeSH
• výběrové chování fyziologie   MeSH
• vysoká zvěř fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• Coccidia MeSH
• hlodavci parazitologie   psychologie   MeSH
• predátorské chování fyziologie   MeSH
• ptáci MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

Neonicotinoids are very effective in controlling crop pests but have adverse effects on predators and pollinators. Spiders are less sensitive to neonicotinoids compared to insects because of the different structure of their acetylcholine receptors, the binding targets of neonicotinoids. We tested whether short-term exposure to neonicotinoids affected the predation rate in different densities of prey of spiders and led to their paralysis or eventual death. To examine these effects, we topically exposed dominant epigeic, epiphytic and sheet-weaving farmland spiders to four widely used neonicotinoids (imidacloprid, thiamethoxam, acetamiprid and thiacloprid). We applied the neonicotinoids at concentrations recommended by the manufacturers for spray application under field conditions. Short-term exposure to the formulations of all four tested neonicotinoids had adverse effects on the predation rate of spiders, with imidacloprid (Confidor) associated with the most severe effects on the predation rate and exhibiting partial acute lethality after one hour (15-32%). Acetamiprid also displayed strong sublethal effects, particularly when applied dorsally to Philodromus cespitum. Day-long exposure to dorsally applied acetamiprid or thiacloprid led to paralysis or death of multiple Linyphiidae spp., with the effects particularly prominent in males. To conclude, we provided multiple lines of evidence that short-term exposure to neonicotinoids, which were applied at recommended field concentrations, caused severe health effects or death in multiple families of spiders. Even acetamiprid caused strong effects, despite being subject to less strict regulations in the European Union, compared with those for imidacloprid because of claims of its negligible off-target toxicity.

• MeSH
• dusíkaté sloučeniny farmakologie   MeSH
• insekticidy farmakologie   MeSH
• neonikotinoidy farmakologie   MeSH
• pavouci účinky léků   MeSH
• predátorské chování účinky léků   MeSH
• thiaziny farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Reproductive activities are often associated with conspicuous morphology or behaviour that could be exploited by predators. Individuals can therefore face a trade-off between reproduction and predation risk. Here we use simple models to explore population-dynamical consequences of such a trade-off for populations subject to a mate-finding Allee effect and an Allee effect due to predation. We present our results in the light of populations that belong to endangered species or pests and study their viability and resilience. We distinguish several qualitative scenarios characterized by the shape and strength of the trade-off and, in particular, identify conditions for which the populations survive or go extinct. Reproduction can be so costly that the population always goes extinct. In other cases, the population goes extinct only over a certain range of low, intermediate or high levels of reproductive activities. Moreover, we show that predator removal (e.g. in an attempt to save an endangered prey species) has the least effect on populations with low cost of reproduction in terms of predation and, conversely, predator addition (e.g. to eradicate a pest) is most effective for populations with high predation cost of reproduction. Our results indicate that a detailed knowledge of the trade-off can be crucial in applications: for some trade-off shapes, only intermediate levels of reproductive activities might guarantee population survival, while they can lead to extinction for others. We therefore suggest that the fate of populations subject to the two antagonistic Allee effects should be evaluated on a case-by-case basis. Although the literature offers no quantitative data on possible trade-off shapes in any taxa, indirect evidence suggests that the trade-off and both Allee effects can occur simultaneously, e.g. in the golden egg bug Phyllomorpha laciniata.

• MeSH
• biologické modely MeSH
• ekosystém MeSH
• hodnocení rizik MeSH
• kompetitivní chování fyziologie   MeSH
• predátorské chování fyziologie   MeSH
• rizikové faktory MeSH
• rozmnožování fyziologie   MeSH
• sexuální chování zvířat fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In Central Europe, protected areas are too small to ensure survival of populations of large carnivores. In the surrounding areas, these species are often persecuted due to competition with game hunters. Therefore, understanding how predation intensity varies spatio-temporally across areas with different levels of protection is fundamental. We investigated the predation patterns of Eurasian lynx (Lynx lynx) on roe deer (Capreolus capreolus) and red deer (Cervus elaphus) in both protected areas and multi-use landscapes of the Bohemian Forest Ecosystem. Based on 359 roe and red deer killed by 10 GPS-collared lynx, we calculated the species-specific annual kill rates and tested for effects of season and lynx age, sex and reproductive status. Because roe and red deer in the study area concentrate in unprotected lowlands during winter, we modeled spatial distribution of kills separately for summer and winter and calculated-the probability of a deer killed by lynx and-the expected number of kills for areas with different levels of protection. Significantly more roe deer (46.05-74.71/year/individual lynx) were killed than red deer (1.57-9.63/year/individual lynx), more deer were killed in winter than in summer, and lynx family groups had higher annual kill rates than adult male, single adult female and subadult female lynx. In winter the probability of a deer killed and the expected number of kills were higher outside the most protected part of the study area than inside; in summer, this probability did not differ between areas, and the expected number of kills was slightly larger inside than outside the most protected part of the study area. This indicates that the intensity of lynx predation in the unprotected part of the Bohemian Forest Ecosystem increases in winter, thus mitigation of conflicts in these areas should be included as a priority in the lynx conservation strategy.

• MeSH
• lesy MeSH
• Lynx * MeSH
• potravní řetězec * MeSH
• predátorské chování * MeSH
• roční období MeSH
• vysoká zvěř * MeSH
• zachování přírodních zdrojů MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

Despite the increasing rate of urbanization, the consequences of this process on biotic interactions remain insufficiently studied. Our aims were to identify the general pattern of urbanization impact on background insect herbivory, to explore variations in this impact related to characteristics of both urban areas and insect-plant systems, and to uncover the factors governing urbanization impacts on insect herbivory. We compared the foliar damage inflicted on the most common trees by defoliating, leafmining and gall-forming insects in rural and urban habitats associated with 16 European cities. In two of these cities, we explored quality of birch foliage for herbivorous insects, mortality of leafmining insects due to predators and parasitoids and bird predation on artificial plasticine larvae. On average, the foliage losses to insects were 16.5% lower in urban than in rural habitats. The magnitude of the overall adverse effect of urbanization on herbivory was independent of the latitude of the locality and was similar in all 11 studied tree species, but increased with an increase in the size of the urban area: it was significant in large cities (city population 1-5 million) but not significant in medium-sized and small towns. Quality of birch foliage for herbivorous insects was slightly higher in urban habitats than in rural habitats. At the same time, leafminer mortality due to ants and birds and the bird attack intensity on dummy larvae were higher in large cities than in rural habitats, which at least partially explained the decline in insect herbivory observed in response to urbanization. Our findings underscore the importance of top-down forces in mediating impacts of urbanization on plant-feeding insects: factors favouring predators may override the positive effects of temperature elevation on insects and thus reduce plant damage.

• MeSH
• býložravci * MeSH
• hmyz * MeSH
• larva MeSH
• listy rostlin MeSH
• predátorské chování * MeSH
• ptáci * MeSH
• stromy MeSH
• velkoměsta MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• velkoměsta MeSH

Population variation in trophic niche is widespread among organisms and is of increasing interest given its role in both speciation and adaptation to changing environments. Trinidadian guppies (Poecilia reticulata) inhabiting stream reaches with different predation regimes have rapidly evolved divergent life history traits. Here, we investigated the effects of both predation and resource availability on guppy trophic niches by evaluating their gut contents, resource standing stocks, and δ15N and δ13C stable isotopes across five streams during the wet season. We found that guppies from low predation (LP) sites had a consistently higher trophic position and proportion of invertebrates in their guts and assimilate less epilithon than guppies from high predation (HP) sites. Higher trophic position was also associated with lower benthic invertebrate availability. Our results suggest that LP guppies could be more efficient invertebrate consumers, possibly as an evolutionary response to greater intraspecific competition for higher quality food. This may be intensified by seasonality, as wet season conditions can alter resource availability, feeding rates, and the intensity of intraspecific competition. Understanding how guppy diets vary among communities is critical to elucidating the role of niche shifts in mediating the link between environmental change and the evolution of life histories.

• MeSH
• biologická evoluce MeSH
• dieta * MeSH
• ekosystém * MeSH
• fyziologická adaptace fyziologie   MeSH
• populační dynamika MeSH
• predátorské chování fyziologie   MeSH
• řeky MeSH
• roční období MeSH
• zeměpis MeSH
• živorodka fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Západoindické souostroví MeSH

Parents make tradeoffs between care for offspring and themselves. Such a tradeoff should be reduced in biparental species, when both parents provide parental care. However, in some biparental species, the contribution of one sex varies greatly over time or between pairs. How this variation in parental care influences self-maintenance rhythms is often unclear. In this study, we used continuous video recording to investigate the daily rhythms of sleep and feather preening in incubating females of the Northern Lapwing (Vanellus vanellus), a wader with a highly variable male contribution to incubation. We found that the female's sleep frequency peaked after sunrise and before sunset but was low in the middle of the day and especially during the night. In contrast, preening frequency followed a 24-h rhythm and peaked in the middle of the day. Taken together, incubating females rarely slept or preened during the night, when the predation pressure was highest. Moreover, the sleeping and preening rhythms were modulated by the male contribution to incubation. Females that were paired with more contributing males showed a stronger sleep rhythm but also a weaker preening rhythm. If more incubating males also invest more in nest guarding and deterring daylight predators, their females may afford more sleep on the nest during the day and preen more when they are off the nest. Whether the lack of sleep in females paired with less caregiving males has fitness consequences awaits future investigation.

• MeSH
• Charadriiformes * MeSH
• cirkadiánní rytmus * MeSH
• hnízdění * MeSH
• matky * MeSH
• otcové * MeSH
• péče o zevnějšek u zvířat * MeSH
• predátorské chování * MeSH
• spánek MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH