Antennal sensilla of the green bottle fly, Lucilia sericata (Meigen) (Diptera: Calliphoridae)

Lucilia sericata (Meigen) is a cosmopolitan synanthropic fly of forensic and medical importance, which can work as a mechanic vector of pathogens or cause myiasis of both human and sheep. As essential olfactory organs, antennae of adult L. sericata were examined with stereoscopic microscope, scanning electron microscope, and laser scanning confocal microscope. On antennal scape and pedicel, both microtirchiae and several bristles are detected, while another two structures, setiferous plaques and pedicellar buttons, are also found on the antennal pedicel. Seven subtypes of antennal sensilla are observed on antennal funiculus including one subtype of trichoid sensilla, two subtypes of basiconic sensilla, two subtypes of coeloconic sensilla, and two subtypes of sensory pits. Size and density of the former four types of sensilla on antennal funiculus are measured. Three distinctive sensillar characters of L. sericata are detected, which may contribute to greater olfactory sensitivity of this species and their wide distribution throughout the world. Unlike the common poreless pedicellar button with mechanoreceptor function, every pedicellar button in L. sericata is perforated by three pores, which might indicate potential chemoreceptor function of this structure. Besides, another unique feature is greater number of setiferous plaques in genus Lucilia than calliphorids of other genera. Expect for the common sensory pits with basiconic or basiconic-like sensilla in them, sensory pits filled with rarely described coeloconic-like sensilla are founded in L. sericata as well. After comparison with previous equivalent findings, the functions of these specific structures are discussed according to the life history of this calliphorid.