Comparisons of Foraging Activities and Competitive Interactions Between the Red Imported Fire Ant (Hymenoptera: Formicidae) and Two Native Ants Under High Soil-Surface Temperatures

摘要

The foraging activities of the red imported fire ant (RIFA), Solenopsis invicta Buren, and two native ant species, Tapinoma melanocephalum Fabricius and Monomorium chinensis Santschi, were investigated with food lures in the hot seasons from June to September 2006. The occurrences and dominances of the three ant species were correlated with soil-surface temperatures. S. invicta and T. melanocephalum exhibited similar responses to high soil-surface temperatures; the occurrence and bait dominance rateof S. invicta and T. melanocephalum declined with the increasing soil-surface temperature. However, the occurrence and dominance of M. chinensis gradually increased from 34-36 deg C and peaked at 48-50 deg C. In most contest cases, M. chinensis was displaced by T. melanocephalum or S. invicta on the baits. From 36 deg C to 46 deg C, displacement rates ofM. chinensisky S. invicta and T. melanocephalum on baits were both about 20%. The results showed the heat-tolerance level of T. melanocephalum was a little higher than S. invicta, and M. chinensis was more heat-tolerant but less aggressive than the other two species.