BIOLOGICAL AND ETHOLOGICAL OBSERVATIONS ON THE INTERACTIONS BETWEEN THE PARASITE ANT FORMICOXENUS-PROVANCHERI AND ITS HOST MYRMICA-INCOMPLETA (HYM-FORMICIDAE)

Information on the biology and the behaviour of Formicoxenus provanche ri, a parasite of Myrmica incompleta, is presented. F. provancheri for ms large polycalic societies with each unit maintaining some independe nce: movements from one unit to another are not frequent and there is brood discrimination between different units. Adoption of Formicoxenus ergates by Myrmica societies is easy, the mortality is very low among the parasites, even if the adoptive Myrmica were previously completel y parasite free. The larvae of Formicoxenus can be eaten by the host M yrmica; this explains the necessity for the Formicoxenus to keep their brood apart from the host. Grooming of the host is very frequent. Thi s might enable the parasite to acquire the species-specific odour of t he host colony. Grooming might also be a way of obtaining some nutriti ous substances from the host body. Appeasement behaviour presented by the Formicoxenus is described. New small units of colonies, at the per iphery of the host society, are probably founded by budding of any fec undated female leaving the nest with some ergates. This leads to the f ormation of super-societies by the parasite. The problem of how the pa rasite spreads is not answered by this study because it was shown that newly fecundated genes suffer strong aggression when they enter an al ien host society.