PARENTAGE AND SEX ALLOCATION IN THE FACULTATIVELY POLYGYNOUS ANT MYRMICA-TAHOENSIS

Most social groups have the potential for reproductive conflict among group members. Within insect societies, reproduction can be divided am ong multiple fertile individuals, leading to potential conflicts betwe en these individuals over the parentage of sexual offspring. Colonies of the facultatively polygynous ant Myrmica tahoensis contain from one to several mated queens. In this species, female sexuals were produce d almost exclusively by one queen. The parentage of male sexuals was m ore complex. In accordance with predictions based on worker sex-alloca tion preferences, male-producing colonies tended to have low levels of genetic relatedness (i.e., high queen numbers). Correspondingly, male s were often reared from the eggs of two or more queens in the nest. F urther, over half of the males produced appeared to be the progeny of fertile workers, not of queens. Overall investment ratios were substan tially more male biased than those predicted by genetic relatedness, s uggesting hidden costs associated with the production of female sexual s. These costs are likely to include local-resource competition among females, most notably when these individuals are adopted by their mate rnal nest.