First record of Hexamermis cf. albicans (Siebold, 1848) (Nematoda: Mermithidae) infecting lepidopteran larvae from Iran

Abstract

During the course of entomological investigations on natural enemies of forest pests in the Arasbaran area, northwest of Iran, a mermithid nematode, Hexamermis cf. albicans was found parasitizing the abdominal cavity of larvae of two lepidopterans, Euproctis chrysorrhoea and Lymantria dispar (Lymantriidae). Infection occurs in the early instars of the host larvae. Parasitism continues until the late instar of the larval host, when the nematode emerges and remains in a post-parasitic free-living stage until it moults into an adult. The mean body length of the parasite ranges from about 14 to 22 cm. One to four mermithids were found per host. About 34% of E. chrysorrhoea and 57% of L. dispar larvae were found to be parasitized by the nematodes. However, the frequency of the parasite varied in different areas. The infection was more frequent in dense as opposed to more sparsely forested regions. This is the first record of Hexamermis cf. albicans (Siebold, 1854) from Iran.