Deuterium δD isotopic analysis is increasingly being used to trace wildlife movement, and undoubtedly has much to offer in this respect but questions still remain as to the feasibility and practicality of the method in ecology. Here we report our attempt to determine the geographic origin of an auxiliary hoverfly, Episyrphus balteatus, in South-western France and a pest moth, Helicoverpa armigera in Western Africa. We used quantile regression to calculate the minimum separation distance, based on the International Atomic Energy Agency / World Meteorological Organization (IAEA / WMO) data, at which two insects could be said to originate from different latitudes with a given degree of confidence. Our results revealed greater variability of hoverfly adults δD in autumn than in spring. From this we infer an autumnal migration of the auxiliary hoverfly species. Despite the complications encountered in Europe, the minimum separation distance model proved a useful first step to get a first range of possible origins of E. balteatus and its application to other arthropod species in Europe warrants investigation. The lack of IAEA /WMO data in western Africa prevents the calculation of a minimum separation distance for the pest moth. The interpretation of water simulated δD in the study area in Western Africa and preliminary results on wild moth advocate for a restricted use of stable isotope to infer the geographical origin of the pest moth.