Morphology of the male reproductive system and spermatozoa of Horiola picta (Coquebert, 1801) (Hemiptera: Membracidae).

Abstract

Membracidae is a family of insects known for its diverse pronotal shapes and coloration, which are used for mimicry. It is common to find species of this family that maintain mutualistic relationships with ants and bees, to which the membracids provide a sweet substance in exchange for protection. One such species with a mutualistic relationship is Horiola picta (Coquebert, 1801) (Smiliinae: Tragopini), considered a cocoa pest in several regions of Brazil. To complement morphological studies, we describe the morphology of the male reproductive system and sperm of H. picta. The male reproductive system is similar to that of other Membracoidea species. However, the number of testicular follicles varies from 12 to 14, which is higher than that observed in other Membracoidea families, which vary from 4 to 13. Based on histology, we observed that follicles contain cysts at different stages of spermatogenesis, suggesting that sperm production is continuous in adulthood and that males copulate multiple times throughout their lives. Furthermore, spermatozoa are long compared to other Membracoidea species, measuring 189.74 ± 1.76 µm in length, and nuclei are 27.30 ± 3.58 µm in length. Two to five terminal flagellar filaments are present, a characteristic unique to Membracoidea and not observed in other groups such as Cercopoidea and Cicadoidea. In the seminal vesicles, the spermatozoa remain organized in spermatodesmata-type bundles, as previously reported in Cicadellidae. This work aims to contribute to knowledge of the species' reproductive biology and to provide relevant morphological data on the reproductive organs, with a view to future taxonomic and phylogenetic analyses of the family and Membracoidea.