FACTORS AFFECTING THE ACCEPTANCE OF ALIEN CONSPECIFICS ON NESTS OF THE PRIMITIVELY EUSOCIAL WASP, ROPALIDIA-MARGINATA (HYMENOPTERA, VESPIDAE)

In the primitively eusocial wasp, Ropalidia marginata, individual fema les are known to drift from one newly founded nest to another. In the laboratory, young (<6- to 8-day-old) alien wasps are accepted onto unr elated colonies, while older (>6- to 8-day-old) wasps are not. Here we have investigated the factors that could influence the acceptance of foreign conspecifics onto unrelated nests. Individually marked wasps o f different ages, isolated immediately after eclosion from the natal n est and from each other, were introduced onto unrelated recipient nest s. Considered separately, both age and ovarian condition seemed to inf luence the probability of acceptance as well as the levels of aggressi on and tolerance received by the introduced wasps. However, partial co rrelation analysis and multiple regression analysis indicated that onl y age had a direct influence and that the ovarian condition acts only through age, a variable with which it is highly correlated. The observ ed acceptance of young aliens and rejection of old aliens are less lik ely to be due to the perception of older wasps as a reproductive threa t rather than some age-related factor, other than ovarian condition, f or example, the relative ease with which younger wasps can be molded i nto desired roles.