Insights into the male reproductive system and spermatozoa of Lutzia bigoti (Diptera: Culicidae)

Abstract

Spermatozoa and the male reproductive system (MRS) present great variability, featuring morphological characters that could be used in the taxonomy of different insect groups. Despite their importance, such data are scarce for mosquitoes, and their potential application in taxonomy has been neglected. In this study, we describe the morphology of the MRS and spermatozoa of the mosquito Lutzia bigoti Bellardi, 1862. The MRS consists of a pair of testes, deferent ducts, seminal vesicles, accessory glands, and an ejaculatory duct. The testes have only a single well-compacted follicle. The deferent ducts originate at the base of each testis, with the first portion resembling a goblet, and present an enlargement that forms the seminal vesicles in the posterior region. Subsequently, the ducts merge with the respective ducts of the accessory glands and open into the ejaculatory duct. The spermatozoa of L. bigoti are characterized as filiform and long, measuring around 220 µm, providing a potential distinguishing feature of this species. We hypothesize that the spiral organization of the testes may confer advantages in spermatozoa production. Similar to other mosquitoes, the MRS organization plan of L. bigoti conforms to type B. In addition, we also suggest that Culicinae species possibly share juxtaposed vesicles. This work paved the way for future analyses exploring of reproductive biology of Lutzia, including ultrastructure examinations and taxonomic investigations in the Culicidae family.