A laboratory trial evaluated four phytoseiid species for their potential as biological control agents of spruce spider mite, Oligonychus ununguis (Jacobi) (Acari: Tetranychidae). An augmentative biological control approach, using the predatory mites Neoseiulus fallacis Garman and Galendromus occidentalis Nesbitt (Acari: Phytoseiidae), was evaluated for reducing pest mite densities and injury, a...

Predator recognition often requires learning by prey individuals. Iberian green frog tadpoles (Pelophylax perezi) have the ability to learn to recognize new potential predators when their chemical cues are found paired with conspecific alarm cues. However, a random pairing of alarm cues and chemical stimuli of a nonpredator might later induce costly antipredator responses to nondangerous specie...

In a radiotracer study designed to evaluate the fate of metals from fish prey to predator fish, we measured the trophic transfer of 7 trace elements (Am, Cd, Co, Cr, Cs, Mn, Zn) from juvenile Mediterranean sea bream Sparus auratus to 3 predator species, the teleosts Psetta maxima and Sparus auratus, and the elasmobranch Scyliorhinus canicula. Prey S. auratus were labeled by exposure to metal ra...

Studies that rigorously measure the effectiveness of anti-predator traits in complex ecological communities are rare. Rarer still are studies that compile the results of these trait analyses in a framework that explains the variation in predation pressure by a predator assemblage. Here the risk of predation by ants is quantified for a community of caterpillar species that employ several putativ...

Many animals must trade-off anti-predator vigilance with other behaviours. Some species facilitate predator detection by joining mixed-species foraging parties and 'eavesdropping' on the predator warnings given by other taxa. Such use of heterospecific warnings presumably reduces the likelihood of predation, but it is unclear whether it also provides wider benefits, by allowing individuals to r...

While effects of urbanization on species assemblages are receiving increasing attention, effects on ecological interactions remain largely unexplored. We investigated how urbanization influences the strength of direct and indirect trophic interactions in a tri- trophic system. In a field experiment including five cities and nearby farmed areas, we used potted Vicia faba plants and manipulated t...

Stage dependent predation may give rise to the hydra effect--the increase of predator density at equilibrium as its mortality rate is raised. Management strategies that adjust predator harvest rates or quotas based on responses of populations to past changes in capture rates may eventually lead to a catastrophic collapse of predator species. A proposed threshold management policy avoids the hyd...

Recently, some biologists have argued that the ratio-dependent predator-prey model is more appropriate than the Gauss-type models for modelling predator-prey interactions where predation involves searching processes. This is strongly supported by numerous laboratory experiments and observations [1, 2, 3, 4, 10, 11, 12]. Many authors [1, 5, 7, 13, 14] have observed that the ratio-dependent preda...

As alarm calls indicate the presence of predators, the correct interpretation of alarm calls, including those of other species, is essential for predator avoidance. Conversely, communication calls of other species might indicate the perceived absence of a predator and hence allow a reduction in vigilance. This "eavesdropping" was demonstrated in birds and mammals, including lemur species. Inter...