A Comparative Study on the Spermatogenesis of Trichoptera and Lepidoptera

Abstract

The insect orders of Trichoptera (caddisflies) and Lepidoptera (moths and butterflies have a strong phylogenetic affinity as indicated by aboundant taxo-morphological data (1, 2). There is, however,disagreement concerning the origin of the divergence of the two orders from the common ancestors, mainly due to lack of clarity on the relative phylogenetic position of Zeugloptera. Zeugloptera is considered by many taxonomists as the most primitive systematic group of Lepidoptera. However, since Zeugloptera has so many “trichopteroid” characteristies others have recognized it as a separate order which might be more archaic than either Trichoptera or Lepidoptera (3). The determination of the phylogenetic position of the lower Lepidoptera is further impeded by paucity of fossils and by disagreement concerning the comparative karyological analysis (4, 5). Comparative spermatology has not been yet applied to the Lepidoptera-Trichoptera evolution.