The relevance of wing geometry in entomological surveillance of Triatominae, vectors of Chagas disease

An important epidemiological challenge in controlling the Triatominae (Hemiptera: Reduviidae), vectors of Chagas disease, is identifying the origin of insects re-infesting treated areas, especially when reinfestation occurs during the first 1 or 2 years following insecticide application and in the absence of insecticide resistance. When using strict insect characteristics, the standard approach is to compare reinfesting specimens with those collected prior to treatment. Because of the long generation time of Triatominae, the experimental intent is to reject the hypothesis of a previous population, the one prior to insecticide application, to be the parental population of the reinfesting population. Biometric techniques are based on the hypothesis of more similarity between offspring and parents, and have been tested in the field. Reinfesting specimens are very few when discovered, which might cause sampling problems. The present study used museum material to test the performance of modern morphometrics to assess the origin of a single individual. A configuration of 13 landmarks was used to assign a single wing to its known parental line or relatives. For the 313 wings tested, correct attribution to the parental line was four times higher than expected at random. Moreover, most of the apparently wrong assignments were not random, but driven by lower levels of kinship. These results suggest that the geometry of the wing contains helpful information to identify the possible source of reinfesting specimens.