Identification based on morphological and molecular characters of Phassus huebneri (Geyer) (Lepidoptera: Hepialidae), a ghost moth feeding on blackberry in Michoacán, Mexico: its biology and parasitoids

Abstract

Larvae of an unidentified Lepidopteran hepialid were found boring stems and crown roots of blackberry (Rubus sp.) in Michoacán, Mexico. In this study, the morphological and molecular identification of larvae and adults of this insect was performed. Preliminary aspects of biology, including information on parasitoids associated to larval stage, are also recorded. A total of 109 larvae of various instars were collected and three were reared to adult. The two females and one male were identified as Phassus huebneri (Geyer) (Lepidoptera: Hepialidae) following morphological characters. This identification was corroborated by comparing the cytochrome oxidase I (COI) barcode of two field-collected larvae (IIAFL1 and IIAFL2) with sequences of Phassus spp. obtained from GenBank. A Neighbor-Joining similarity analysis yielded a phenogram with two subclades. The first subclade grouped the IIAFL1 and IIAFL2 sequences with two other Mexican sequences categorized as P. huebneri, whereas in the second subclade other species belonging to the genus Phassus from Guatemala and Costa Rica were grouped together. Larval development of nine instars took about 14 months. Larvae reached a maximum length of 10 cm. The pupal stage lasted 39–41 days. Each of the two females laid over 1,000 unfertilized eggs within a period of 48 h. Larvae were parasitized by Dinera grisescens Fallen (Diptera: Tachinidae) and another unidentified Dinera sp. This study provides additional evidences on the distribution pattern of P. huebneri in western Mexico and presents the first record of this species feeding on one of the most economically important crops in Mexico.