Some like it hot: effects of temperature and fine-scale resource distribution on ant community domination

In order to coexist in sympatry, subordinate species must somehow obtain resources that dominant taxa may generally control. We examined 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 (6g) was partitioned as 1, 8, or 64 items in a 0.4m 2 area, near nests of the dominant ant Monomorium sydneyense Forel, during a variety of temperatures. As the number of food items increased, a significant increase in the number of species utilizing the food was observed, associated with an increase in the unutilized proportion of food items. The changing occupation rates of food items by M. sydneyense and three other species was modelled against soil surface temperature and the varying dispersion rate of the food resource. We observed significant main effects of density, site, species, and temperature 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. There was considerable variation between species in their response to variation in temperature and food distribution. Though 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 had a limit to the number of resources that they could secure.