Alerta e fuga: efeito do inseticida imidacloprido na comunicação de alarme e no comportamento de Nasutitermes corniger (Motschulsky 1855)(Termitidae: Nasutitermitinae)

Abstract

Termites (Blattodea: Isoptera) have a range of defensive strategies in order to maintain colony protection against imminent dangers. The sophisticated alarm communication present in this group ensures that colony members avoid contact with predators, competitors and even pathogens. On the other hand, the effect of toxic substances, such as insecticides, on alarm communication and behavior has not yet been elucidated. Here, we analyze the effects of the insecticide imidacloprid on the alarm communication and behavior of Nasutitermes corniger (Termitidae: Nasutitermitinae). For this, we tested the following hypotheses: (i) the insecticide triggers alert behavior in termites, through an increase in the number of vibrations; (ii) this alert behavior is dose-dependent on the insecticide and (iii) the alert behavior triggers an escape behavior of groups of termites not exposed to the insecticide. Manipulative alarm and behavioral bioassays were performed in the laboratory in order to test the above hypotheses. In general, our results demonstrated that, in fact, groups of N. corniger exposed to the insecticide imidacloprid increase the number of vibrations, triggering an alert behavior. However, there is a decrease in walking activity in groups exposed to the insecticide. The alert response, via vibration, in the groups exposed to the insecticide is dose dependent. In addition, groups exposed to the insecticide can transmit the presence of the insecticide via vibration to non-exposed groups, triggering an escape behavior. Our results demonstrate the existence of an 'insecticide alert behavior' in N. corniger and it seems to be a previously unrecognized communication mechanism in termites that allows reducing the risks of intoxication in the colony.