Wing chemoreceptors of Glossina pallidipes (Diptera: Glossinidae) and Stomoxys nigra (Diptera: Muscidae)

Abstract

A comparative study has been made of the wing sense organs, specifically the chemoreceptors, of two trypanosomosis vectors: Glossina pallidipes Austen, 1903 (cyclical transmission) and Stomoxys nigra Macquart, 1850 (mechanical transmission). Chemoreceptor morphology, distribution and role are analyzed in relation to sexual differences and intra-, interspecific variations. G. pallidipes has a greater number of chemoreceptors than S. nigra. Comparisons are made with other Glossina spp. and with Musca domestica. Globally and by sections, G. pallidipes have more chemoreceptors (males: 138.26; females: 135.33) than S. nigra (males: 89.85; females: 95.68) but less than G. m. morsitans (males: 173.17; females: 168), G. m. submorsitans (males: 169.29; females: 169.52) or G. austeni (males: 160.58; females: 156.47). The difference in chemoreceptor numbers between males and females within the same species is not significant. Section E of S. nigra is better provided with chemoreceptors in both sexes, sections A and F are devoid of them. The distribution of chemoreceptors along the costal vein is limited to sections B, C, D and E, while it is on the whole costal vein in tsetse flies. The possible roles of the chemoreceptors in reproduction, environmental perception and host-finding are discussed.