Protein detection in spermatids and spermatozoa of the butterfly Euptoieta hegesia (Lepidoptera)

This study was undertaken to detect protein components in both sperm types of the butterfly Euptoieta hegesia. These spermatozoa possess complex extracellular structures for which the composition and functional significance are still unclear. In the apyrene sperm head, the proteic cap presented an external ring and an internal dense content; basic proteins were detected only in external portions. In the tail, the paracrystalline core of mitochondrial derivatives and the axoneme are rich in proteins. The extratesticular spermatozoa are covered by a proteic coat, which presented two distinct layers. In eupyrene spermatozoa, acrosome and nucleus were negatively stained, probably because of their high compaction. In the tail, there is no paracrystalline core and the axoneme presented a very specific reaction for basic proteins. The lacinate and reticular appendages are composed of cylindrical sub-units and presented a light reaction to E-PTA and a strong reaction to tannic acid. A complex proteic coat also covers the extratesticular spermatozoa. We found similarities between both extratesticular coats, indicating a possible common origin. Both spermatozoon types are rich in proteins, especially the eupyrene appendages and the extratesticular coats. We believe that both coats are related to the sperm maturation and capacitation processes.

Dichotomic spermiogenesis in Euptoieta hegesia(Lepidoptera: Nymphalidae)

Butterflies and moths produce enucleate (apyrene) and nucleate (eupyrene) spermatozoa. However, most studies oflepidopteran spermatogenesis and spermiogenesis have used only larvae and pupae. In this work, we used light andtransmission electron microscopy to examine spermiogenesis in males of the butterfly Euptoieta hegesia. Only adultmales were used, because this species has a long adult lifespan during which all cell stages can be observed. Male E.hegesia had a single fused testis with cysts that exclusively contained either apyrene or eupyrene cells. The mainevents of apyrene spermiogenesis included the formation, transformation and elimination of micronuclei, dense capformation, the development of mitochondrial derivatives and tail elongation. Eupyrene spermiogenesis involvedacrosome formation, nuclear condensation and elongation, extracellular appendage development, formation ofmitochondrial derivatives and tail elongation. The pattern and events of apyrene and eupyrene spermiogenesis in E.hegesia corroborate and complement data in the literature, particularly with regard to the intermediate developmentalstages of some structures, such as the acrosome, axoneme and extracellular appendages.