Data from: Intraspecific support for the polygyny-vs.-polyandry hypothesis in the bulldog ant Myrmecia brevinoda

The number of queens per colony and the number of matings per queen are
the most important determinants of the genetic structure of ant colonies,
and understanding their interrelationship is essential to the study of
social evolution. The polygyny-versus-polyandry hypothesis argues that
polygyny and polyandry should be negatively associated since both can
result in increased intracolonial genetic variability and have costs.
However, evidence for this long-debated hypothesis has been lacking at the
intraspecific level. Here, we investigated the colony genetic structure in
the Australian bulldog ant Myrmecia brevinoda. The numbers of queens per
colony varied from 1 to 6. Nestmate queens within polygynous colonies were
on average related (rqq = 0.171±0.019), but the overall relatedness
between queens and their mates was indistinguishable from zero (rqm =
0.037±0.030). Queens were inferred to mate with 1 to 10 males. A lack of
genetic isolation by distance among nests indicated the prevalence of
independent colony foundation. In accordance with the
polygyny-versus-polyandry hypothesis, the number of queens per colony was
significantly negatively associated with the estimated number of matings
(Spearman rank correlation R = -0.490, P = 0.028). This study thus
provides rare intraspecific evidence for the polygyny-versus-polyandry
hypothesis. We suggest that high costs of multiple matings and the strong
effect of multiple mating on intracolonial genetic diversity may be
essential to the negative association between polygyny and polyandry, and
that any attempt to empirically test this hypothesis should place emphasis
upon these two key underlying aspects.