Foraging chemical signals in the Neotropical termite Nasutitermes corniger (Motschulsky, 1855) (Termitidae: Nasutitermitinae): the role of castes and the intercolonial perception

Abstract

Social insects are known to have complex and elaborate communication systems. Communication through chemical signals is paramount in termites since these insects are blind and have cryptic habits. Despite this, knowledge about the role of chemical signals in termites is still scarce, especially in phylogenetically derived species. Here, we aimed to investigate the role of foraging chemical signals in Nasutitermes corniger (Termitidae: Nasutitermitinae), including the effect of different anatomical sources of foraging chemical signals, the response of groups with different caste compositions, and the colony-specificity of these signals. Specifically, we tested the following hypotheses: (i) rectal fluid and sternal gland extracts have different roles in perception, orientation, and acceptance by groups of N. corniger with different caste compositions; (ii) the behavior of N. corniger exposed to intercolonial foraging signals is not altered; and (iii) intercolonial foraging signals have attractive activity on N. corniger. To do so, trail, behavior and attraction/repellent bioassays were carried out in the laboratory. The sternal gland extract triggered greater trail behavior than the other foraging signals. Furthermore, the rectal fluid extract seems to exert an orientation function in N. corniger while the sternal gland extract acts as a recruitment signal. Finally, the behavior and attractiveness of the intercolonial foraging signals were not altered when compared with the control. The results found in the present study increase the understanding of foraging chemical communication in Isoptera and reinforce the role of intercolonial signals in the attractiveness of groups of N. corniger.