1Lehrstuhl Tierphysiologie, Universität Bayreuth, 95440 Bayreuth, Germany.
2Zoologisches Institut, Universität Bern, Erlachstr. 9a, 3012 Bern, Switzerland.
3Umweltforschungszentrum Leipzig-Halle, Theodor-Lieser-Straße 4, 06120 Halle, Germany.
The origin of labels used to discriminate nestmates from aliens is unknown. In principal there are two possibilities: labels are either collected from the environment or produced by the individuals/colonies. For the latter case, cuticular hydrocarbons or related compounds are discussed. Thus we investigated aggressiveness in the termite Macrotermes subhyalinus in correlation with inter-colonial differences in cuticular hydrocarbon compositions. The results are: (1) We observed the full range of aggression from no aggression between individuals up to pairings in which most individuals were killed. (2) Between years there was a good correlation of aggression, although the general level of aggression was higher in 1997 than in 1996. Thus the environmental situation mould the level of aggression. (3) Aggression was not correlated with the spatial distance between colonies. Thus, there was no indication of a dear-enemy phenomenon. (4) Aggression was not correlated with differences size or age of the colonies. (5) We found a very strong correlation of aggression between colonies with the differences in the hydrocarbon compositions. We conclude that in M. subhyalinus chemical cues, which trigger aggression, are produced by biochemical pathways of the termites and may be biased by the genetics and may thus depend on the relatedness between colonies.