Dilema do predador: Se arriscar ou não por uma presa que oferece risco de injúria na presença de pistas de competição?

Abstract

According to optimal foraging theory, generalist predators prefer prey that offers the highest energetic return. However, the risk of injury imposed by the prey and competition with other predators can influence the predator’s foraging decisions, leading it to capture prey that provides a lower energetic return. Jumping spiders may be susceptible to these two factors. Thus, it is possible that upon detecting cues from a competitor, the spider becomes more likely to attack a more dangerous prey, as the density of easier-to-capture prey should decrease when competitors are present. In this study, we tested whether females of the jumping spider Corythalia conferta avoid prey that poses a higher risk of injury but increase their attacks in the presence of cues from conspecific spiders. In laboratory arenas, we offered the spiders ants that presented different levels of injury risk and used the dragline silk of another spider as a competitor signal. C. conferta avoided ants that posed a higher risk of injury, but even though they exhibited behavioral changes in the presence of the competitor’s silk, they did not alter their foraging decisions. This suggests that the risk posed by prey has a greater impact on C. conferta’s foraging decisions than competition with conspecifics.