Ultrastructure of antennal sensory organs in Wohlfahrtia magnifica (Diptera: Sarcophagidae)

Wohlfahrtia magnifica (Schiner 1861) is the sole causative agent of vaginal myiasis in Bactrian camels, and its antennal sensilla serve as essential sensory organs for detecting environmental chemical cues. However, no systematic study has been reported on the morphology of antennal sensilla in male and female. Here, we examined and compared the antennal morphology of male and female W. magnifica using scanning electron microscopy. The antennae consist of 3 main segments, the scape, pedicel, and funiculus, with an arista arising from the funiculus. Four sensillum types were identified: chaetica, trichodea, basiconica, and coeloconica. The total antennal, scape and funiculus lengths were significantly greater in females than in males. Females also bore significantly more olfactory pits on the funiculus. In males, Str I exhibited a significantly shorter but a significantly larger basal diameter and abundance than in females, with micropores on their surfaces. Both the length and abundance of Ba II and III were significantly greater in females than in males. Males showed significantly greater length and basal diameter of Co than did females. These findings demonstrate clear sexual dimorphism in the antennal sensilla of W. magnifica. Females appear to have a sensory advantage, potentially facilitating host location and larviposition site selection, whereas the specialized, porous Str I in males may be involved in sex pheromone detection. This study provides a morphological basis for future investigations into the mechanisms underlying host location and mate recognition, as well as for the development of attractants and repellents for this species.