Search results for "Predation"
showing 10 items of 589 documents
Exploring individual and population eco-evolutionary feedbacks under the coupled effects of fishing and predation
2020
Intensive fishing that selects for large and old individuals can have pervasive effects on traits directly associated with the fecundity and survival of the target species. The observed reduction in fish body size can result in earlier sexual maturity at a smaller body size, leading to a lower individual reproductive output and population productivity in the long term. In addition, increased predation can induce similar responses in age and size at maturity due to the release of intraspecific competition and the lower population density. Thus, the combined impact of fisheries and predation is more difficult to predict due to their competition for fish, ultimately limiting and directing the …
Effects of food abundance and early clutch predation on reproductive timing in a high Arctic shorebird exposed to advancements in arthropod abundance.
2016
12 pages; International audience; Climate change may influence the phenology of organisms unequally across trophic levels and thus lead to phenological mismatches between predators and prey. In cases where prey availability peaks before reproducing predators reach maximal prey demand, any negative fitness consequences would selectively favor resynchronization by earlier starts of the reproductive activities of the predators. At a study site in northeast Greenland, over a period of 17 years, the median emergence of the invertebrate prey of Sanderling Calidris alba advanced with 1.27 days per year. Yet, over the same period Sanderling did not advance hatching date. Thus, Sanderlings increasin…
Discriminating uniparental and biparental breeding strategies by monitoring nest temperature
2017
10 pages; International audience; Birds exhibit a wide diversity of breeding strategies. During incubation or chick-rearing, parental care can be either uniparental, by either the male or the female, or biparental. Understanding the selective pressures that drive these different strategies represents an exciting challenge for ecologists. In this context, assigning the type of parental care at the nest (e.g. biparental or uniparental incubation strategy) is often a prerequisite to answering questions in evolutionary ecology. The aim of this study was to produce a standardized method unequivocally to assign an incubation strategy to any Sanderling Calidris alba nest found in the field by moni…
Occupation of wood warbler Phylloscopus sibilatrix nests by Myrmica and Lasius ants
2018
Bird nests can provide habitats for various invertebrates, including ectoparasites, scavengers, and predators. Records of ants associating with active bird nests mostly involve the insects searching for food, with some exceptional records of ants raising their broods (eggs, larvae or pupae) within songbird nests in nest-boxes or tree cavities. We present data for a previously undocumented, but apparently regular, occurrence of ants and their broods within the active nests of a songbird, the wood warbler Phylloscopus sibilatrix (Bechstein, 1793), which builds domed nests on the ground in European forests. Systematic recording found ants, mostly Myrmica ruginodis Nylander, 1846, in 43% of 80 …
Camouflage accuracy in Sahara–Sahel desert rodents
2020
1. Camouflage helps animals to hide from predators and is therefore key to survival. Although widespread convergence of animal phenotypes to their natural environment is well-established, there is a lack of knowledge about how species compromise camouflage accuracy across different background types in their habitat.2. Here we tested how background matching has responded to top–down selection by avian and mammalian predators using Sahara–Sahel desert rodents in North Africa.3. We show that the fur colouration of several species has become an accurate match to different types of desert habitats. This is supported by a correlation analysis of colour and pattern metrics, investigation of animal…
Modelling sensitive elasmobranchs habitat
2013
Basic information on the distribution and habitat preferences of ecologically important species is essential for their management and protection. In the Mediterranean Sea there is increasing concern over elasmobranch species because their biological (ecological) characteristics make them highly vulnerable to fishing pressure. Their removal could affect the structure and function of marine ecosystems, inducing changes in trophic interactions at the community level due to the selective elimination of predators or prey species, competitors and species replacement. In this study Bayesian hierarchical spatial models are used to map the sensitive habitats of the three most caught elasmobranch spe…
Parasite transmission in aquatic ecosystems under temperature change: effects of host activity and elimination of parasite larvae by filter‐feeders
2020
A moderate raise in temperature was suggested to enhance the impact of parasites on aquatic ecosystems. Under higher temperatures, poikilothermic animals (e.g. fish) increase their activity, which can result in a more frequent encounter with parasites. However, temperature increase may also trigger processes counteracting an increased risk of parasitic infections. Thus, the removal of free‐living stages of parasites by filter‐feeding organisms can increase with temperature and potentially mitigate disease risk in ecosystems under climate change. We aimed to study whether an increased infection transmission under higher temperatures can be compensated by the increased removal of parasitic la…
Predation on Multiple Trophic Levels Shapes the Evolution of Pathogen Virulence
2009
The pathogen virulence is traditionally thought to co-evolve as a result of reciprocal selection with its host organism. In natural communities, pathogens and hosts are typically embedded within a web of interactions with other species, which could affect indirectly the pathogen virulence and host immunity through trade-offs. Here we show that selection by predation can affect both pathogen virulence and host immune defence. Exposing opportunistic bacterial pathogen Serratia marcescens to predation by protozoan Tetrahymena thermophila decreased its virulence when measured as host moth Parasemia plantaginis survival. This was probably because the bacterial anti-predatory traits were traded o…
Communal nesting in the garden dormouse (Eliomys quercinus)
2017
Communal nesting has been described in many rodents including some dormouse species. In this study, we report the existence of this reproductive strategy in the garden dormouse Eliomys quercinus. Data was recorded by checking natural nests and nest-boxes from 2003 to 2013 in SE Spain. Pups and adults dormice found in nests were captured and marked. Overall, 198 nests were found: 161 (81.31%) were singular nests and 37 (18.69%) were communal nests. Communal nests were composed by different combinations of one up to three females together with one up to three different size litters. The number of communal nests varied from year to year in accordance with the number of singular nests and no se…
Bachelor groups form due to individual choices or environmental disrupters in African striped mice
2021
International audience; In several mammal species, bachelor groups occur as a regular life history stage between dispersal and becoming the breeding male of a multi-female group. However, it is rarely investigated how such groups come into existence and how males that choose this strategy differ in life history traits from other males. Males of the socially flexible African striped mouse Rhabdomys pumilio have been historically reported to adopt one of three alternative tactics, i.e., small group-living philopatric males, intermediate solitary living roaming males, or large group-living territorial males. Here, we describe for the first time, bachelors as a fourth male tactic. Using long-te…