The wing interference patterns (WIPs) of Parapanteles (Braconidae, Microgastrinae): demonstrating a powerful and accessible tool for species-level identification of small and clear winged insects

Abstract

Wing interference patterns (WIPs) are color patterns of insect wings caused by thin film interference. Thin film interference is the same phenomenon responsible for the refracted spectral colors sometimes visible on soap bubbles. Insect WIPs are static patterns due to the variable thickness of wing membranes and the colors produced depend on the thicknesses of wing membranes. While WIPs have been studied in several taxa of small insects, they have not been broadly adopted by insect taxonomists. We surveyed WIPs in one moderate-sized genus of parasitoid wasps, Parapanteles (Braconidae: Microgastrinae). Using an inexpensive microscope camera set-up and free imaging and analysis software, we detected consistent WIP differences between Parapanteles species. In some cases, WIPs can be used to diagnose sibling species that would otherwise require SEM images to differentiate or DNA barcodes. Wing interference patters are an underemployed character that may be similarly useful in many other taxa of small clear-winged insects.