Search results for "Predation"

A manipulative parasite increasing an antipredator response decreases its vulnerability to a nonhost predator.

2009

8 pages; International audience; Trophically transmitted parasites have to deal with the antipredator adaptations of their intermediate hosts. Some of these parasites induce behavioural changes in their intermediate hosts that make them more vulnerable to predation by definitive hosts. However, the adaptiveness of behavioural manipulation also depends on the probability of being eaten by a nonhost predator. Parasites might therefore try to use specific antipredator responses of intermediate hosts to avoid this dead end. We tested this hypothesis using the acanthocephalan Polymorphus minutus and its intermediate amphipod host, Gammarus roeseli. In their natural habitat, uninfected G. roeseli…

Factors influencing infection patterns of trophically transmitted parasites among a fish community: host diet, host-parasite compatibility or both?

2011

20 pages; International audience; Parasite infection patterns were compared with the occurrence of their intermediate hosts in the diet of nine sympatric fish species in a New Zealand lake. Stomach contents and infection levels of three gastrointestinal helminth species were examined from the entire fish community. The results highlighted some links between fish host diet and the flow of trophically transmitted helminths. Stomach contents indicated that all but one fish species were exposed to these helminths through their diet. Host feeding behaviour best explained infection patterns of the trematode Coitocaecum parvum among the fish community. Infection levels of the nematode Hedruris spi…

Bird and amphipod parasites illustrate a gradient from adaptation to exaptation in complex life cycle.

2010

6 pages; International audience; Trophically transmitted parasites modify the phenotype of their hosts, sometimes in a way that facilitates transmission. Parasite-induced changes can be either part of a manipulative strategy evolved to improve the transmission success of the parasite, or simply by-products of infection with no health effect. In the former case, manipulation is regarded as a parasite adaptation driven by the probability of being eaten by a suitable next host. Here, we consider the fact that manipulation may also be an 'exaptation': a trait that evolved for a certain use, but which has been co-opted for a new use. According to this view, features built by natural selection fo…

Key carabid species drive spring weed seed predation of Viola arvensis

2020

Specific color sensitivities of prey and predator explain camouflage in different visual systems

2004

In situations of aggressive mimicry, predators adapt their color to that of the substrate on which they sit for hunting, a behavior that is presumed to hide them from prey as well as from their own predators. Females of few crab-spider species encounter such situations when lying on flowers to ambush pollinators. To evaluate the efficiency of spider camouflage on flowers, we measured by spectroradiometry adult female Thomisus onustus and marguerite daisies, Leucanthemum vulgare. We compared chromatic contrast (color used for short-range detection) of each pair of spider and flower to detection thresholds computed in the visual systems of both Hymenopteran prey and passerine bird predator. W…

In utero behavioral imprinting to predation risk in pups of the bank vole

2020

Abstract In the predator–prey arms race, survival-enhancing adaptive behaviors are essential. Prey can perceive predator presence directly from visual, auditory, or chemical cues. Non-lethal encounters with a predator may trigger prey to produce special body odors, alarm pheromones, informing conspecifics about predation risks. Recent studies suggest that parental exposure to predation risk during reproduction affects offspring behavior cross-generationally. We compared behaviors of bank vole (Myodes glareolus) pups produced by parents exposed to one of three treatments: predator scent from the least weasel (Mustela nivalis nivalis); scent from weasel-exposed voles, i.e., alarm pheromones;…

Predator presence may benefit: kestrels protect curlew nests against nest predators.

1994

We studied whether the presence of breeding kestrels (Falco tinnunculus) affected nest predation and breeding habitat selection of curlews (Numenius arquata) on an open flat farmland area in western Finland. We searched for nests of curlews from an area of 6 km2 during 1985–1993. For each nest found, we recorded the fate of the nest, and the distance to the nearest kestrel nest and to the nearest perch. We measured the impact of breeding kestrels on nest predation by constructing artificial curlew nests in the vicinity of ten kestrel nests in 1993. Curlew nests were closer to kestrel nests than expected from random distribution, eventhough kestrels fed on average 5.5% of curlew chick produc…

Parasite-induced suppression of aggregation under predation risk in a freshwater amphipod

2012

a b s t r a c t Recent findings suggest that grouping with conspecifics is part of the behavioural defences developed by amphipod crustaceans to face predation risk by fish. Amphipods commonly serve as intermediate hosts for trophically transmitted parasites. These parasites are known for their ability to alter intermediate host phenotype in a way that promotes predation by definitive hosts, where they reproduce. If aggregation in amphipods dilutes the risk to be preyed on by fish, then it may dilute the probability of transmission for the parasite using fish as definitive hosts. Using experimental infections, we tested whether infection with the fish acanthocephalan Pomphorhynchus laevis a…

Predation risk and reproduction in the bank vole

2012

Context Life-history strategies are the means that organisms use to achieve successful reproduction in environments that vary in time and space. Individual animals maximise life-time reproductive success (LRS) through optimal timing of reproduction and investment in offspring. A crucial factor affecting LRS is predation risk in a highly seasonal environment. According to the breeding-suppression hypothesis (BSH), females should delay breeding under short periods of high predation risk. Delayed breeding under risk is suggested to have substantial consequences for females’ fitness. Aims We tested the BSH in an iteroparous boreal small rodent, the bank vole, Myodes glareolus. Methods We used …

The invasive stink bug Halyomorpha halys affects the reproductive success and the experience-mediated behavioural responses of the egg parasitoid Tri…

2021

Invasive species, because of their lack of co-evolutionary history with recipient communities, can act as “evolutionary traps” causing disconnects between natural enemy behavioural responses and the suitability of the invasive species as a prey/host resource. Invasion of exotic species in non-native environments may have several ecological effects, including consequences for the experience-mediated behavioural responses of indigenous foragers. Experience is usually thought to help resident species to buffer against negative impacts of new invasive species, including escaping from evolutionary traps. Here we hypothesized that the impact of foraging experience depends on whether an indigenous…