Foraging and Communication Ecology of the Common Green Bottle Fly, Lucilia sericata (Meigen) (Diptera: Calliphoridae)

In accordance with their physiological state, adults of Lucilia sericata must locate mates, food and oviposition resources. I investigated the cues they exploit to obtain these resources. As females require a protein-rich diet and frequently visit pollen/protein-rich flowers, I studied the effects of generic floral scent and colour cues, and of Oxeye daisy-specific cues, on foraging decisions by flies. I show that (1) flies in the presence of generic floral scent respond more strongly to a uniformly yellow cue than to most other uniform colour cues (green, white, black, blue, red); (2) daisy scent enhances the attractiveness of a yellow cue; and (3) pollen with adequate moisture content facilitates oocyte maturation of flies. Males respond to long-range mate recognition cues. I show that (1) wing movement of females is a visual mate recognition cue, (2) wings are thin-film reflectors that produce light flashes during movement, and (3) light flashes are absent under diffuse light. Wings also produce stable structural colours, UV- and polarized-light reflections, but these optic effects per se are insufficiently gender-specific and thus do not appear to serve as mate recognition cues. Instead, the frequency of light flashes reflected off moving female wings may allow males to recognize prospective mates.Foraging decisions by females change in accordance with their physiological state. Protein-hungry females respond to feces and carrion, whereas protein-fed gravid females with mature oocytes respond only to fresh carrion. Gravid females discriminate against aging carrion (which is detrimental to their offspring) as soon as it produces appreciable amounts of indole, which is an abundant feces semiochemical and apparently serves as an indicator of a food rather than an oviposition resource. Gravid females locate recently deceased vertebrates as oviposition sites in response to dimethyl trisulfide and carrion-type colour cues (dark red, black), indicating that a bimodal cue complex signifies suitable oviposition sites.Oviposition site-seeking females do not respond to an oviposition pheromone. Instead, they coopt semiochemicals associated with feeding flies as resource indicators. This conclusion is based on data that gravid or non-gravid females ovipositing and/or feeding on oviposition resources enhance their attractiveness to gravid and non-gravid females.