Change in movement and subdivision of Myrmica punctiventris (Hymenoptera, Formicidae) colonies in north temperate forests is related to a long-term shift in social organization

We assessed temporal and spatial patterns of nest site use in the cavity dwelling ant, Myrmica punctiventris in a well-studied temperate forest site in central New York State. We evaluated changes in nest site use by repeatedly censusing the ants inhabiting artificial nests (hollow dowels) for three consecutive growing seasons. We confirm a shift towards more polydomy in this population of M. punctiventris, first reported by DeHeer et al. (2001), but extend these findings by demonstrating that this shift has occurred gradually over several years. We are unable to determine if this polydomy is seasonal or year round. We explore various explanations for the occurrence of polydomy and suggest that long-term changes in sex allocation are indirectly driving the shift in nesting strategies. Received 15 July 2004; revised 11 April and 19 October 2005; accepted 25 October.