Sensory organs of forensically important fly Ophyra capensis (Wiedemann, 1818) (Diptera: Muscidae): A scanning electron microscopic study.

Dipterans, especially the sarcosaprophagous communities are of substantial importance from medical, veterinary and forensic entomological perspectives. Muscids are generally seen to colonize carcasses at advanced stages of decomposition when the initial dominance of calliphorids and sarcophagids subsides. Ophyra capensis (Wiedemann, 1818), a muscid fly with a relatively wide distribution range is considered of decent forensic relevance as it has been reported not only from cadavers placed outdoors but also from graves and exhumed corpses. The prime objective of the present study is to analyse and interpret the ultrastructural morphology of three sensory organs, namely, the ocellar region, compound eye and antenna of adult male and female Ophyra capensis with the help of scanning electron microscopy, so as to facilitate accurate morphological identification of the species in forensic entomological investigations. SEM analysis of the ocellar region revealed that it was larger in size in females and covered with microtrichia. Ultrastructural analysis of the compound eye indicated that the antero-frontally located ommatidia were larger in size in comparison to the rest of the facets, along with notable sexual dimorphism regarding the size of the ommatidia. The ultrastructure of the antenna displayed the presence of five types of sensilla, two types of chaetic sensilla on the scape and pedicel; trichoid sensilla and two types of basiconic sensilla on the flagellum along with numerous microtrichia. Both types of basiconic sensilla displayed a multiporous surface indicating their characteristic olfactory function. The morphological characteristics of these sensilla along with their probable functions are discussed in greater details.