No abstract

Aggressive behaviour can ensure animal access to local resources. To reduce constant costs in the defence of territories, species could save energy with conflicts avoiding aggression with neighbour or in situations with abundance of resources. In the present study, we analysed the effect of distance among colonies and resource availability on the aggression level and responses to chemical cues of Nasutitermes aff. coxipoensis (Holmgren) (Termitidae: Nasutitermitinae). Manipulation of resource offer was conducted in the field, where nests with different distances were kept without addition of baits (control), with addition of three or 16 sugarcane baits/nest. After 3 months, aggressiveness, linear and Y-shaped trail-following bioassays were carried out with all pairwise combinations of colonies in each treatment. Our results showed that aggressive index of N. aff. coxipoensis was affected by the resource availability. However, individuals from colonies with 0 and 3 baits/nest showed a higher number of fighting with neighbours than those from non-neighbours colonies. Termite workers from colonies without baits (control) followed shorter distance in the linear trails compared to those from colonies with addition of baits. In all treatments, there was no preference of workers in relation to the choice of chemical cues from own or other colonies. The response of intercolonial aggressiveness in N. aff. coxipoensis seems to be resource-dependent. These results may contribute to the comprehension of the use of space by N. aff. coxipoensis and could be useful to explain patterns of termite co-occurrence at different spatial scales, from local (inside the nest-e.g. cohabitation of nests by inquilines) to regional (e.g. around the nest).

Social insects have an efficient recognition system that guarantees social cohesion and protection against intruders in their colonies and territories. However, the energy costs in constant conflicts with neighboring colonies could promote a reduction in the fitness of colonies. Here, we evaluated the effect of previous exposure to allocolonial odor and the consumption of similar food resources on aggressive behavior and choice of allocolonial cues in Nasutitermes aff. coxipoensis (Termitidae: Nasutitermitinae). Our results showed that intercolonial aggressiveness was not affected by previous exposure to allocolonial odor and by the consumption of similar food resources. However, individuals previously exposed to allocolonial odor were more attracted to these odors than individuals who had no prior exposure to allocolonial odor. In addition, individuals from colonies of N. aff. coxipoensis that use similar food resources increased alertness via a greater number of vibration than individuals who consumed different food resources. In general, our results indicate that colonies of N. aff coxipoensis perceive allocolonial cues that have been previously exposed and that the consumption of similar resources triggers an alert signal between individuals. Additional studies are necessary to assess how widespread this capacity of perception is present among the different Isoptera groups and the consequences of colony recognition odor cues on termite space use.

No abstract

Termite colonies are protected by the physical structure of the nest as well as by an elaborate system of recognition against intruders. Nevertheless, the defensive system does not always prevent colonization of termite nests by other species. Here, we analyzed whether the host-inquiline cohabitation could occur through mechanisms related to the specificity of chemical cue acquisition by inquilines or through avoidance, testing the hypotheses that (i) there is lower survival and greater aggressiveness between host and inquiline coming from different nests than between those from the same nest; (ii) there is lower survival between host and inquiline coming from the nests of different locals than between those species from the same local; and (ii) intestinal or body cues may be repellent for inquilines or hosts. Manipulative bioassays were conducted pairing hosts and inquilines coming from the same and different nests. Our results showed that although there was greater mortality of the host and inquiline in close contact, they showed mutual recognition of cues without displaying any aggressive behavior. The host was attracted by inquiline body cues and the inquiline was attracted by the host’s intestinal and body cues. Hosts did not distinguish inquilines from different nests in the same locality; however, inquilines seemed to be more habituated to their own host nests than to other nests. Our results suggest that local and genetic factors may be related to cues involved in this coexistence. Therefore, under natural conditions, we hypothesized that mechanisms, such as segregation and camouflaging, could maintain cohabitation.

Nests of the termite Constrictotermes sp. can be cohabited by obligatory inquilines Inquilinitermes sp. Recent studies have shown that inquilines establish themselves in mature nests, possibly during the nidification transition phase of the colony (e.g., from the epigeal to the arboreal habit). It is believed that cohabitation is maintained through spatial segregation of the cohabitants since the inquilines aggregate in the central nest region. Here, we described the cohabitation between Inquilinitermes microceus (Silvestri) and a Constrictotermes species in Sergipe, Northeast Brazil. We compared the cohabitation observed in distinct regions considering hypotheses related to the entry and maintenance of the inquiline in the nests. All Constrictotermes sp. nests found in this region are epigeal, unlike already reported in other studies. Approximately 45% of the nests analyzed were associated with I. microcerus, and cohabitation seemed to be dependent on nest size. The entrance of the inquiline was not related to changes in the nidification habit from soil to trees, as suggested in other studies. In addition, inquilines were not associated with and segregated into the dark walls in the central part of the nest. The cohabitation observed here could involve mechanisms which are distinct from the mechanisms reported in other regions.

No 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.