Flight properties of orthorrhaphous Brachycera flies in tethered flight performance (Insecta : Diptera)

Abstract

Flight properties were examined for orthorrhaphous Brachycera flies with automatically recording flight-mills installing a magnetic floating system. Species examined were wild individuals of Tabanidae (Tabanus trigonus Coquillett and Hirosia iyoensis (Shiraki)), Asilidae (Cophinopoda chinensis (Fabricius) and Promachus yesonicus Bigot), and Stratiomydae (Hermetia illucens (Linnaeus)). Properties measured were distance of total flight (DIT), distance of the most sustained flight (DIS), duration of total flight (DUT), duration of the most sustained flight (DUS), speed of total flight (SPT), speed of the most sustained flight (SPS), and speed of the fast 1km flight (SPF). T. trigonus exhibited strong flight capability with mean values of DIT (8.1km), DUT (115.1 min.), SPT (1.49m/sec), and maximum values of DIS (11.6km), DUS (125.9min.), SPS (2.9m/sec), and SPF (3.44m/sec). Two asilid species and H. iyoensis showed smaller values in these properties. A stratiomyid species, H. illucens, showed rather larger values, with mean values of DIT (17.5km), DUT (210.2min.), SPT (0.98m/sec), and maximum values of DIS (11.03km), DUS (238.2min.), SPS (1.2m/sec), and SPF (1.83m/sec). The maximum dispersal range at a time was 36.6km for H. illucens and 33.1Km for T. trigonus, and less than 3.2km for other species. A tendency of a rapid flight as well as a long distance and propensity was recognized in T. trigonus, and a slow flight as well as a long distance and propensity in H. illucens. These properties of flights seemed to be derived from the flight pattern in their intrinsic behavior for foraging food resources. Their specialized body plans in relation to adult food habits seemed to characterize flight pattern respecting to carnivorous, bloodsuckers, nectar feeders, or scavengers.