The Behavior and Natural History of Hybosciara gigantea (Diptera: Sciaridae)

Larvae of Hybosciara gigantea fed on leaf litter and formed compact masses of up to several hundred individuals. Sex ratios were often highly biased, and varied widely in different masses. Given the fact that in some sciarid species females are able to produce only a single sex of offspring, larvae in masses were probably often siblings; several other aspects of the flies's natural history were in accord with this hypothesis. Young adult females, but apparently not males, dispersed long distances. Males formed loose ephemeral swarms near vegetation where copulation occurred.