The influence of temperature and fine-scale resource distribution on resource sharing and domination in an ant community

1. In order to coexist in sympatry, subordinate species must somehow obtain resources that dominant taxa may generally control. This study examines the response of an ant community to fine-scale variation in resource distribution, as a mechanism enabling resource acquisition by subordinates in the presence of dominant taxa. Food (6 g) was portioned as one, eight, or 64 items in a 0.4-m(2) area, centred on nests of Monomorium sydneyense Forel, considered the most dominant ant in the area. This ant is a newly established exotic species in our study site of Tauranga, New Zealand. 2. As the number of food items increased, a significant increase in the number of species utilising the food was observed, associated with an increase in the non-utilised proportion of food items. 3. The changing occupation rates of food items by M. sydneyense and three other species were modelled against soil surface temperature and the varying dispersion rates of the food resource. Significant main effects of food density, site, species, and temperature were observed on the probability of food being occupied by a species. However, there were also significant interaction effects, making it impossible to interpret the main effects in isolation. Monomorium sydneyense dominated a smaller proportion of resources in trials with increased resource distribution and cooler temperatures, allowing more species to access resources. 4. There was considerable variation between species in their responses to variation in temperature and food distribution. Although most species were able to respond to increasing resource dispersion, species that were in low abundance apparently could not. However, even species that could respond to increasing resource dispersion were limited in the number of resources they could secure.