GENETIC RELATEDNESS AND COLONY STRUCTURE IN POLYGYNOUS MYRMICA ANTS

Genetic relatedness is a key parameter in the kin selection theory for the evolution of altruistic behaviour. In the present study relatedne ss was examined in three facultatively polygynous red ants, Myrmica sc abrinodis and M. gallienii (both among worker and queen nestmates), an d M. sabuleti (among workers). Relatedness among workers generally agr eed with the expectations based on queen number being positive in all species (range: 0.12-0.55), but in most cases significantly lower than 0.75. In M. scabrinodis, relatedness among coexisting queens was high (r = 0.66) and significantly higher than among workers in the same co lonies (r = 0.25), which suggests production of new sexual females by a subset of queens. In M. gallienii, coexisting queens were not relate d (r = 0.01), which results from the high degree of polygyny in the po pulation studied. When data were available for workers and queens, the y were used to calculate the effective number of queens (N-e) in the c olonies. N-e was higher in M. scabrinodis than the observed number of queens (N-e = 6.5 vs x(h) = 2.1). This was either due to the rapid tur nover of queens in Myrmica or the polydomous structure of the colonies .