Intraspecific colony recognition in the termites Macrotermes subhyalinus and Macrotermes bellicosus (Isoptera, Termitidae)
Intraspecific colony recognition in the termites Macrotermes subhyalinus and M. bellicosus was investigated over two field seasons in Comoë-Nationalpark (Ivory Coast). Behavioural tests with major workers and minor soldiers, respectively, were performed using neutral arenas of covered plastic dishes. For each species, termites were sampled by baiting from 10 field colonies randomly chosen at four different sites. Major workers and minor soldiers of both species were capable of differentially discriminating between members of various colonies. In major workers of M. subhyalinus this discriminatory ability was expressed as varying degrees of aggression, whereas major workers of M. bellicosus showed different degrees of examination behaviour. Minor soldiers of both species reacted to foreign colony members with different levels of aggression. Thus, M. bellicosus displayed a more subtle form of discriminatory behaviour. Mound volume was measured as a parameter for colony size and stage of colony development. Aggression (in major workers of M. subhyalinus) and examination behaviour (in major workers of M. bellicosus) were not correlated with differences in mound volume and thus differences in size or age of the involved colonies. Aggression and examination behaviour respectively of major workers were not correlated either with the spatial distance between the colonies. We found cases, where individuals from neighbouring colonies showed either no aggression/examination behaviour or a high level of aggression/examination behaviour. Thus, there was no indication of a dear-enemy phenomenon. The behaviour of colony discrimination was found to be consistent over the two years for both species.