Efeito da proporção de soldados na percepção de pistas de risco durante a seleção de recursos em cupins.

Abstract

In nature, animals face complex situations in the search and choice of food resources, which may be accompanied by negative interactions, requiring organisms to evaluate the benefits and costs during foraging. In this process, animals use information (private or social) obtained from the environment, and this perception is even more sophisticated in social insects, where decision-making is done collectively. In the present study, we evaluated the effect of the proportion of soldiers on the perception of the change in intensity of risk cues during the selection of food resources in Nasutitermes corniger (Termitidae: Nasutitermitinae). To do so, we tested the hypothesis that increasing the proportion of soldiers in groups of N. corniger increases the ability to perceive changes in risk cues during the selection of food resources. Initially, field experiments were conducted to verify the ant species that preyed the most on termites so that we could use the chemical signals of this predator as risk cues. Next, free-choice resource selection bioassays were carried out in the laboratory to evaluate the choice of groups of 30 termites in different soldier proportions (0 to 100%) for resources with different intensities of risk cues (4 uL - low or 20 uL - high), where the resources were alternated after 19h from the beginning of the experiment. A control experiment was performed without exchanging resources between arenas. In general, our results demonstrated that the presence of the soldier caste plays an essential role in the perception of risk cues, where an increase in its proportion triggers a greater perception of risk cues during the selection of food resources. This mechanism can significantly influence the understanding of the different functions that the soldier can have within the nest, the evolution of this caste, the pattern of habitat use, and the foraging of termites.