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Thermal environment and nutritional condition affect the efficacy of chemical alarm cues produced by prey fish

Lienart, Govinda D. H., Ferrari, Maud C. O., McCormick, Mark I.
Environmental biology of fishes 2016 v.99 no.10 pp. 729-739
Pomacentrus, body condition, energy, fish, food availability, juveniles, oceans, predator-prey relationships, temperature
A wide variety of prey animals possess damage-released chemical alarm cues that evoke antipredator responses in both conspecifics and some heterospecifics. Several studies have indicated that food availability may influence body condition and in doing so, affect the production of alarm cues. We examined whether food availability (high and low) and temperature (27, 30 and 32 °C) interacted to affect the production of chemical alarm cues by juveniles of a marine tropical prey fish, Pomacentrus moluccensis. Results indicate that poorly-fed fish had depleted energy reserves with rising temperatures compared to well-fed fish. Fish with a poor feeding history also showed depressed growth rate across all temperature treatments. The alarm cues produced by experimental fish triggered stronger antipredator responses as temperature increased up to 30 °C, regardless of the feeding history or body condition of the donor. However, at 32 °C, alarm cues from poorly-fed fish did not elicit as effectively an antipredator response in conspecifics compared to those produced by well-fed fish. The results highlight that warming oceans, in isolation but also in conjunction with changes in food supply, may have a drastic impact on chemically-mediated predator-prey interactions.