MORPHOLOGICAL PREDICTION OF WORKER SIZE DISCRIMINATION AND RELATIVE ABUNDANCE OF SYMPARTIC SPECIES OF PSEUDACTEON (DIPT, PHORIDAE) PARASITOIDS OF THE FIRE ANT, SOLENOPSIS-SAEVISSIMA (HYM, FORMICIDAE) IN BRAZIL

Patterns of attack for collected species of phorids are predicted usin g multivariate morphometrics of female Pseudacteon species and worker size distributions of parasitized fire ants, Solenopsis saevissima. Th e model assumes that there is a direct correlation between phorid size and the size range of the worker ant attacked, and presumes that work er sizes are a resource that is divided by sympatric phorid species to minimize joint parasitism. These results suggest that the community o f sympatric Pseudacteon species on only one host species coexists by r estricting the size of workers attacked, and secondarily by differing diel patterns of ovipositional activity. When we compared relative abu ndance of species of Pseudacteon with the size distribution of forager s of S. saevissima, our observed distribution did not differ significa ntly from our predicted relative abundance of females of Pseudacteon. The activity of Pseudacteon may be a factor determining forager size d istributions.