The anatomy, histology, and physiology of the reproductive systems of Lytta nuttalli Say (Coleoptera: Meloidae). II. The abdomen and external genitalia

Abstract

The abdomen of adult Lytta nuttalli is composed of 10 segments, the first 8 of which are well developed, except for the first two sterna. The last two segments are concealed within the eighth. The ninth segment of the male is represented by a pair of hemitergites dorsolateral to the genital chamber and a ventral sternum, which supports the aedeagus. The aedeagus is typical of the vaginate type of male coleopteran genitalia. Seven pairs of muscles and an unpaired muscle associated with the aedeagus and ninth sternum are involved in copulation. The female ninth segment is made up of a pair of hemitergites dorsolateral to the genital chamber and a pair of ventrolateral hemisternites bearing styli. These structures are characteristic of the compact type of female beetle genitalia. Bristles on the styli probably have a tactile function in copulation and possibly in oviposition. The 10th segment of both sexes consists of a pair of heavily sclerotized hemitergites dorsolateral and a lightly sclerotized sternum ventral lo the anus. The form and functions of the external genitalia of L. nuttalli are compared with those of other Meloidae and other Coleoptera.