Deforestation reduces nest mound size and decreases the production of sexual offspring in the wood ant Formica aquilonia

Little is known about how anthropogenic changes in nature affect reproduction in social insects such as ants. We studied the effects of clear-cutting on the production of sexual offspring and on the mound size in Formica aquilonia, using neighbouring uncut forests as controls. Nest mounds were smaller in clear-cuts, apparently because they tended to be new bud nests. The basal area of nest mounds decreased towards forest edges. The production of sexual offspring increased with nest mound size. Clear-cutting reduced the production of sexual offspring also when the effect of nest mound size had been factored out. Our results show that anthropogenic changes do have the potential to modify the production of sexual offspring in social insect.