Effets d'un régulateur de croissance d'insectes,le fénoxycarbe,sur la diapause du psylle du poirier Cacopsylla pyri

The nature of the responses of the sheep blowfly Lucilia sericata Meigen (Diptera: Calliphoridae) to carrion odours and carbon dioxide were examined in a windtunnel in the laboratory and the attractiveness of carrion-bait was examined in the field. In the wind tunnel, gravid 9-day-old females increased both the number and duration of their flights, in response to carrion odours. In addition, linear velocity was reduced and the sinuosity of flight increased in the presence of these odours. With 3-day-old females, the response to carrrion odour depended on previous exposure to proteinaceous material. Protein deprived females showed kinetic responses to carrionodour which were similar to those of gravid females. No such changes were observed in protein-fed females. No responses to CO₂ were observed. In the field, the importance of olfactory cues in bait location was demonstrated by the absence of L. sericata from sticky targets lacking an odour bait. Increased bait concentration did not affect the age, sex ratio or ratio of L. sericata to other Lucilia spp. caught, but did increase the numbers caught. Analysis of the reproductive status of females caught, indicated that a greater number of gravid females were caught than expected, while a lower number of females in the final stages of vitellogenesis were caught than expected. The results show that the responses of L. sericata to odours are complex, and are dependent on both exogenous and endogenous stimuli, the latter including the stage of ovarian development.