LARVIPOSITION BEHAVIOR OF SARCOPHAGA-BULLATA (DIPTERA, CALLIPHORIDAE)- DESCRIPTION AND AN EXPLORATION OF THE ROLES OF OLFACTION AND TASTE

Larviposition and associated behaviors are described from detailed obs ervations of 8- to 12-day-old Sarcophaga 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 sucro se) 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). Od or of liver homogenate coupled with access to the sucrose feeding subs trate did not stimulate larviposition, and dilution of the liver homog enate by as little as 50% reduced its effectiveness as a larviposition substrate. It was concluded that taste plays a crucial role in releas ing larviposition in this fly. Evidence is also provided for a role fo r olfaction as a modulator of the threshold for releasing larvipositio n. In flies showing two or more larviposition bouts, the first larvipo sition event increased the readiness of a fly to larviposit when given a second opportunity, and the presence of liver odor in the fly's env ironment between larviposition bouts enhanced this threshold lowering effect. the results are discussed with reference to reported studies o n several Calliphoridae.