Megaselia steptoeae (Diptera: Phoridae): specialists on smashed snails.

Females of the phorid fly Megaselia steptoeae Hartop et al. (Diptera: Phoridae) were found to be quickly attracted to crushed glass snails of the species Oxychilus draparnaudi (Beck) (Gastropoda: Oxychilidae). Most females were without mature eggs and apparently were attracted for feeding purposes only; other injured molluscs offered at the same time were not attractive. One female laid eggs in captivity and offspring were reared to the pupal stage. The lifestyle of this species is similar to that of parasitoids of injured ants, which also require separate hosts of the same species for feeding and oviposition. We conclude that injured hosts must be common in the environment to attract these host-specific scavengers.