Predation avoidance behavior and web investment are not constrained by individual nutritional status in a shelter-building spider species

Abstract

Optimal foraging and individual specialization theories suggest that different properties of the interaction between prey and predators determine foraging strategies. However, none of them consider how the nutritional status of the predators and the risk of being attacked by other predators can affect the option for these strategies. Some spider species can build webs as dynamic traps to capture prey and perform behaviors that optimize capture efficiency while adopting strategies to minimize their exposure to predators, such as building a shelter. In this sense, the risk of predation during foraging and the nutritional status of spiders may be important factors mediating predator-prey interactions, because capturing prey involves leaving the shelter, which may contribute to an increased risk of exposure to predators lurking close to the web. In this study, we evaluated the hypotheses that individuals of the shelter-building spider Metazygia laticeps (Araneidae) with poor nutritional status (i) are more exposed to predators during foraging and (ii) invest more in web structures to capture prey. Nutritional status was unrelated to exposure to predation. However, M. laticeps individuals left the shelter faster at night than during the day, regardless of their nutritional status, probably to reduce exposure to visually oriented predators. In addition, individuals with poor nutritional status did not show higher investment in webs when compared to well-nourished spiders. Nutritional status, therefore, was not a determining factor modulating investment in web foraging structures by M. laticeps.