Geometric Morphometric for third instar larva identification of forensically important blowflies in Thailand

Abstract

Fly identification is the first crucial step in forensic entomology. However, morphological and molecular techniques are considered as common and/or routine method, the limitation that requires a technician and financial resources still exists. Since the geometric morphometric approach has been increasingly published over the last decades, this tool is interesting for the classification and identification of insects. This study assessed the geometric morphometric (GM) analysis to the posterior spiracles for species identification of 800 third-instar larva of eight medically and forensically important including, Chrysomya chani Kurahashi, Chrysomya megacephala (Fabricius), Chrysomya (Ceylonomyia) nigripes Aubertin, Chrysomya pinguis (Walker), Chrysomya (Achoetandrus) rufifacies (Macquart), Hemipyrellia ligurriens (Wiedemann), Lucilia cuprina (Wiedemann), and Lucilia porphyrina (Walker). The cross-validation based on the posterior spiracles geometry shown a relatively high percentage of correct classification in most species, ranking from 86% to 100%. The results of this study proved that the GM analysis applied to the posterior spiracles of fly larvae might be an effective identification tool. Hence, this GM method represents the potential to serve as a utilized tool when morphological and molecular limitations arise, and the output of this study will be useful for further studies.