When one does not want, two fight less: low mobility and similar odors result in peaceful interspecific encounters in termites

Abstract

The cohabitation in nests of eusocial insects may involve different strategies that allow the stable coexistence. Here, we investigated the role of mobility and whole body odors in interspecific encounters in termites. Specifically, we tested the hypothesis that aggressiveness is reduced in interspecific encounters when: i) one of the involved species has low mobility; and/or ii) non-nestmate individuals share similar whole body odor. Manipulative bioassays were conducted to evaluate the proportion of attacks between the host species (Constrictotermes sp.) and target individuals: inquiline (Inquinitermes microcerus) and non-inquiline species (Nasutitermes corniger). The treatments consisted of the manipulation of combinations between the mobility (immovable or free) and odor of the target species and variation in host castes (S: soldier, W: worker, or S + W: both castes). For odor manipulation, the body watery extract was used to treat the species with each other's odors. Host and treated target individuals were inserted into the arena to determine the time elapsed until the first attack. Hosts and inquilines exhibited low aggression towards each other. The host's attack on the inquiline varied only among castes, with greater aggressiveness in the presence of the host worker (W or S + W). The proportion of attacks by the host on non-inquilines, and vice versa, was greater when the non-inquiline was free and had its own odor, followed by a neutral odor, the odor of inquiline, or the host. Our results suggest that low mobility and acquisition of similar odors can reduce interspecific aggression. These results contribute to the understanding of the mechanisms involved in the interactions between termites and other eusocial species.