Search results for "Predator"
showing 10 items of 349 documents
Comparison of the functional responses of invasive and native amphipods
2008
While we can usually understand the impacts of invasive species on recipient communities, invasion biology lacks methodologies that are potentially more predictive. Such tools should ideally be straightforward and widely applicable. Here, we explore an approach that compares the functional responses (FRs) of invader and native amphipod crustaceans. Dikerogammarus villosus is a Ponto-Caspian amphipod currently invading Europe and poised to invade North America. Compared with other amphipods that it actively replaces in freshwaters, D. villosus exhibited significantly greater predation, consuming significantly more prey with a higher type II FR. This corroborates the known dramatic field imp…
The challenge of the predatory open-access publishing outbreak
2019
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The importance of pattern similarity between Müllerian mimics in predator avoidance learning
2004
Müllerian mimicry, where unpalatable prey share common warning patterns, has long fascinated evolutionary biologists. It is commonly assumed that Müllerian mimics benefit by sharing the costs of predator education, thus reducing per capita mortality, although there has been no direct test of this assumption. Here, we specifically measure the selection pressure exerted by avian predators on unpalatable prey with different degrees of visual similarity in their warning patterns. Using wild-caught birds foraging on novel patterned prey in the laboratory, we unexpectedly found that pattern similarity did not increase the speed of avoidance learning, and even dissimilar mimics shared the educatio…
Response of bird predators for female wood tiger moth chemical defences
2018
Multiple behavioural responses of blue tit predators to the defence fluids of wood tiger moth (Arctia plantaginis) females that were either food deprived or fed ad libitum during development.
Change in take-off elevation angle after limb autotomy mitigates the reduction in jumping distance in rice grasshoppersOxya yezoensis
2013
Autotomy is the ability to spontaneously self-amputate a limb or other appendage, often as a reflexive action. This limb amputation typically occurs as a specialized defensive response to an attack from a predator and thereby enables the prey to escape from predation. Despite the benefits of escape, autotomized organisms lose the body part and its associated function. Here, we investigated the jumping behavior and performance of one-leg-autotomized and intact rice grasshoppers, Oxya yezoensis, to examine changes in jumping behavior after autotomy. The take-off elevation of autotomized grasshoppers was 7.8° lower than in intact grasshoppers, resulting in nearly a 45° angle of take-off, which…
Olfactory attraction of the hornet Vespa velutina to honeybee colony odors and pheromones.
2014
19 pages; International audience; Since the beginning of the last century, the number of biological invasions has continuously increased worldwide. Due to their environmental and economical consequences, invasive species are now a major concern. Social wasps are particularly efficient invaders because of their distinctive biology and behavior. Among them, the yellow-legged hornet, Vespa velutina, is a keen hunter of domestic honeybees. Its recent introduction to Europe may induce important beekeeping, pollination, and biodiversity problems. Hornets use olfactory cues for the long-range detection of food sources, in this case the location of honeybee colonies, but the exact nature of these c…
Prey-predator strategies in a multiagent system
2006
This paper describes the prey-predator multiagent system which can be considered as an abstraction of more complex real-world models. Both the prey and the predators are considered as autonomous agents with their own behaviors and perception of the environment. In particular, we propose a simulator which lets study different strategies such as cooperation and individualism. An extensive experiment has been carried out in order to prove the effectiveness of the latter.
Evolution of avian clutch size along latitudinal gradients: do seasonality, nest predation or breeding season length matter?
2010
Birds display a latitudinal gradient in clutch size with smaller clutches in the tropics and larger in the temperate region. Three factors have been proposed to affect this pattern: seasonality of resources (SR), nest predation and length of the breeding season (LBS). Here, we test the importance of these factors by modelling clutch size evolution within bird populations under different environmental settings. We use an individual-based ecogenetic simulation model that combines principles from population ecology and life history theory. Results suggest that increasing SR from the tropics to the poles by itself or in combination with a decreasing predation rate and LBS can generate the latit…
Behavioural interactions in stream food webs: the case of drift-feeding fish, predatory invertebrates and grazing mayflies
1999
Summary 1. We examined direct and indirect behavioural responses of grazing mayfly nymphs (Baetis rhodani) to predation risk from a drift-feeding fish (European minnow; odour manipulated), and two types of invertebrate predators, Diura bicaudata (stonefly) and Rhyacophila nubila (caddis larva). We also assessed the direct responses of the invertebrate predators to fish chemicals. 2. Based on diel gut content periodicity, D. bicaudata nymphs were strongly nocturnal foragers. R. nubila was also nocturnal, but only in a fish stream; in a stream lacking fish, their gut contents did not vary significantly on a diel basis. In the laboratory, Diura was nocturnal even in the absence of fish and alm…
Complementary methods assessing short and long-term prey of a marine top predator ‒ Application to the grey seal-fishery conflict in the Baltic Sea.
2019
The growing grey seal (Halichoerus grypus) population in the Baltic Sea has created conflicts with local fisheries, comparable to similar emerging problems worldwide. Adequate information on the foraging habits is a requirement for responsible management of the seal population. We investigated the applicability of available dietary assessment methods by comparing morphological analysis and DNA metabarcoding of gut contents (short-term diet; n = 129/125 seals, respectively), and tissue chemical markers i.e. fatty acid (FA) profiles of blubber and stable isotopes (SIs) of liver and muscle (mid- or long-term diet; n = 108 seals for the FA and SI markers). The methods provided complementary inf…