ANTS IN TROPICAL IRRIGATED RICE - DISTRIBUTION AND ABUNDANCE, ESPECIALLY OF SOLENOPSIS-GEMINATA (HYMENOPTERA, FORMICIDAE)

At least 62 species of ants were caught at baits in Philippine rice fi elds, notably in the bunds (levees) of irrigated rice. Many were relat ively uncommon or localized. Apart from the ubiquitous Tapinoma sp. nr indicum Forel the most widespread was the aggressive Solenopsis gemin ata (Fabricius) which was often very abundant in fields with bunds tha t were disturbed by regular repair. This ant was scarce or absent in r elatively undisturbed well-vegetated bunds where Pheidole spp. were so metimes common and where up to 14 different species were recorded in b unds of a single field. Colonies were spaced out along the bunds where foraging territories sometimes overlapped, except for those of the co mpeting dominants S. geminata and Pheidole spp. In general, S. geminat a retained its overall foraging areas from year to year but those of n on-dominant ant species could vary considerably. Bunds of low-lying fi elds that are deeply flooded in the wet season were recolonized by S. geminata in the wet season. This ant occurred as separate colonies wit h workers from nests that differed in degree of mutual aggression. Suc h aggression was not observed in foraging areas. Solenopsis geminata a nd other species foraged into, and nested within, dry fallowed fields after the crop was harvested. In the crop season, they foraged across mud during periods of up to one week when farmers allow irrigated rice fields to drain before flooding. Solenopsis geminata workers also for aged across the closed crop canopy. At such times they were commonly o bserved preying on hemipteran and lepidopteran pests and on eggs and y oung golden snails (Pomacea canaliculata Lamarck) which are serious ri ce pests in the Philippines.