First report of aberrant sperm in Edessinae and analysis of the male reproductive system of Edessa rufomarginata (De Geer, 1773) (Hemiptera: Pentatomidae).

Edessinae is one of the ten subfamilies of Pentatomidae, and it is further divided into seven genera. Among these, Edessa Fabricius, 1803 is the most diverse genus, boasting around 300 species recognized for their ecological and economic significance worldwide. The inclusion of various pentatomids in the Edessa genus has led to mistakes in its taxonomy due to common morphological features and misidentifications. An alternative to avoid mistakes is to use diverse datasets to characterize and classify insects, such as the male reproductive system and sperm morphology, for their variability and conserved traits within a clade. Thus, we described the morphology of the male reproductive system, spermatozoa, and spermiogenesis of Edessa rufomarginata (De Geer, 1773) using light microscopy. We discovered that their male reproductive system consists of a pair of elongated testes with four follicles each. The analysis revealed for the first time the presence of dimorphic spermatozoa in Edessinae. There are two distinct morphotypes: spermatozoa type I, produced by follicles 1, 2, and 3, with a total length of approximately 325 μm and a nucleus of 34 μm and spermatozoa type II, produced by follicle 4, measuring approximately 156 μm in total length and 73 μm in the nucleus, and showing an aberrant sperm morphology with different morphology from what has been described in Pentatomidae. The presence of sperm dimorphism in E. rufomarginata are not reported in any other Pentatomidae to date, and it may contribute to establishing taxonomic limits within the subfamily Edessinae.