Comparative Morphology of Meloidodera spp. and Verutus sp. (Heteroderidae) with Scanning Electron Microscopy

Scanning electron microscopy (SEM) of second-stage juveniles (J2), males, and females of Meloidodera floridensis, M. charis, M. belli, and Verutus volvingentis reveals detailed characteristics of the head region, lateral field, phasmid, body striae, vulva, and perineal region. In M. charis and M. belli the en face pattern conforms to a basic pattern in which the labial disc is surrounded by six lips (sectors) of the first head annulation. In J2 the head has additional annulations, whereas in males annulation is replaced by longitudinal blocks. Conversely, J2 and males of M. floridensis and V. volvingentis each have a unique derived face pattern with fusion of various lip components and with head annulation. All six lips of females of M. charis and M. belli are fused, whereas females of M. floridensis and V. volvingentis have distinct lateral lips. Lateral fields vary among species, with only slight differences at the anterior and posterior ends of the lateral lines and in the spatial relation of the lines to phasmid openings. Phasmid openings are present in adults of Meloidodera spp., but were not observed in adults of V. volvingentis; in this respect, the female perineal pattern of Verutus is different from Meloidodera spp, The very large vulva (+/- 48 mum long) of V. volvingentis is in sharp contrast to the minute vulva (+/- 6 mum long) in a population of M. charis from San Bernardino. Morphological characters revealed by SEM will be most informative when investigated throughout Heteroderidae and incorporated with additional characters for a phylogenetic analysis of the family.