Larval newts adjust foraging rate to perceived predator and competitor proximity

摘要: Foraging is key for most animals, because their energy and matter income depend on food ingestion. However, animals may respond adaptively to perceived competitor and/or predator proximity by modifying foraging rates. Increased activity expected improve the chances of succeeding in competition. benefits increased could be offset risks conspicuousness predators. Plus, starvation have counteracting or additive effects behaviour. Here, we test these hypotheses larval Iberian ribbed newts (Pleurodeles waltl). We estimated rates individuals haphazardly assigned either a restricted an unrestricted-feeding regime, water with (1) self-odour as control, (2) Dytiscus sp. chemical cues, (3) conspecific larva cues. Treatments were presented random sequence. Newt larvae responded cues increasing relative control. Conspecific over other two treatments. Feeding regime did not modify response proximity. presence simultaneously energetic status face competition reduce prey available competitor. Intermediate suggest trade-off between (likely improved accelerated metamorphosis) costs conspicuousness) These results prove that adjust