On the larval morphology of Micropterix aruncella (Scopoli, 1763) (Lepidoptera: Micropterigidae).

Abstract

Larvae and adults of M. aruncella were collected from alpine pasture land near the tree line (2000 m a.s.l., Stubai Valley, northern Tyrol, Central Alps, Austria). 158 larvae were extracted from the superficial soil using the Kempson technique (Meyer 1980) between May and October 1998. 81 adults (42 males, 39 females) were collected in emergence traps between July 10 and August 23, 2001. The integument of the larvae exhibits numerous modifications such as folds, bulges, discs and conical structures. The external anatomy of the mouthparts, antennae and legs are documented by SEM micrographs and original drawings. The frequency distribution of head capsule width of the investigated larvae falls into 4 groups indicative of four instar larvae which according to a progression scale increase at each molt by a ratio of 1.2. - 1.7. The first instar larvae were present only in May. By autumn all had reached the fourth stage. After overwintering, the adults emerged between the middle of July and the middle of August, feasible a two-year life cycle.

Keywords

Lepidoptera, Micropterigidae, Micropterix aruncella, larval morphology, Central Alps, North Tyrol, alpine pasture land.