In Middle Asia, the dragonfly Pantala flavescens makes regular seasonal migrations. In spring, sexually mature dragonflies (immigrants) arrive in this region for reproduction. Dragonflies of the aboriginal generation (residents) develop in about two months, and migrate south in autumn. Residents of Middle Asia have significantly lower δ2H values (-123.5 (SD 17.2)‱, n = 53) than immigrants (-64.4 (9.7)‱, n = 12), as well as aboriginal dragonfly species from Ethiopia (-47.9 (10.8)‱, n = 4) and the Sahel zone (-50.1 (15.5)‱, n = 11). Phenological data on P. flavescens in the Afro-Asian region and a comparison with published isotopic data on migratory insects from this region suggest that (i) the probable area of origin of P. flavescens immigrants is located in tropical parts of East Africa and/or the Arabian Peninsula and (ii) the autumn migration of Middle Asian residents to the south may also pass through the Indian Ocean. We assume that in the Afro-Asian region, there is an extensive migration circle of P. flavescens covering East Africa, Central Asia and the Indian subcontinent with a total length of more than 14,000 km.
Keywords: deuterium; dragonfly; globe skimmer; isotopic ecology; latitudinal migration; migratory insect; phenology.