Larviposition behavior ofSarcophaga bullata (diptera: Calliphoridae): Description and an exploration of the roles of olfaction and taste

Abstract

Larviposition and associated behaviors are described from detailed observations of 8-to 12-day-oldSarcophaga bullata females. Tasting and feeding were almost always closely associated with larviposition. The roles of olfaction and taste in releasing larviposition behavior were investigated by offering a stimulatory feeding substrate (100 mM sucrose) in the presence or absence of larviposition substrate odor and by determining the effect of dilution and distillation on the stimulating capacity of an optimal larviposition substrate (liver homogenate). Odor of liver homogenate coupled with access to the sucrose feeding substrate did not stimulate larviposition, and dilution of the liver homogenate by as little as 50% reduced its effectiveness as a larviposition substrate. It was concluded that taste plays a crucial role in releasing larviposition in this fly. Evidence is also provided for a role for olfaction as a modulator of the threshold for releasing larviposition. In flies showing two or more larviposition bouts, the first larviposition event increased the readiness of a fly to larviposit when given a second opportunity, and the presence of liver odor in the fly's environment between larviposition bouts enhanced this threshold lowering effect. The results are discussed with reference to reported studies on several Calliphoridae.