GENETIC RELATEDNESS AMONG WORKER NESTMATES OF 3 FORMICINE SLAVE-MAKING ANTS

We estimated genetic relatedness among worker nestmates of the faculta tive slave-making ant Formica subnuda (28 colonies), and the obligate slavemakers F. subintegra (19 colonies) and Polyergus breviceps (14 co lonies) using horizontal starch gel electrophoresis. Relatedness among nestmates was 0.42 in F. subnuda, 0.70 in F. subintegra, and 0.49 in P. breviceps on average. Relatedness of F. subintegra workers did not differ significantly from 0.75 indicating that this species is monogyn ous, though some females may mate multiply. The estimates of F. subnud a and P. breviceps were significantly lower than 0.75 and, consequentl y, colonies were polygynous and/or polyandrous. The inbreeding coeffic ients were close to zero in all species suggesting random mating. We s uggest that owing to practical monogyny and obligate nature of its sla vemaking, F. subintegra a is a good species for tests of sex allocatio n theory.