Spermathecae: Morphofunctional features and correlation with fat bodies and trachea in six species of vectors of Chagas disease

Trends in Taxonomy of Chagas Disease Vectors (Hemiptera, Reduviidae, Triatominae): From Linnaean to Integrative Taxonomy

Chagas disease is a neglected tropical disease caused by the protozoan Trypanosoma cruzi and transmitted mainly by members of the subfamily Triatominae. There are currently 157 species, grouped into 18 genera and five tribes. Most descriptions of triatomine species are based on classical taxonomy. Facing evolutionary (cryptic speciation and phenotypic plasticity) and taxonomic (more than 190 synonymizations) problems, it is evident that integrative taxonomy studies are an important and necessary trend for this group of vectors. Almost two-and-a-half centuries after the description of the first species, we present for the first time the state-of-the-art taxonomy of the whole subfamily, covering from the initial classic studies to the use of integrative taxonomy.

Pronounced Postmating Response in the Drosophila Female Reproductive Tract Fluid Proteome

Fertility depends on the progression of complex and coordinated postmating processes within the extracellular environment of the female reproductive tract (FRT). Molecular interactions between ejaculate and FRT proteins regulate many of these processes, including sperm motility, migration, storage, and modification, along with concurrent changes in the female. Although extensive progress has been made in the proteomic characterization of the male-derived components of sperm and seminal fluid, investigations into the FRT have remained more limited. To achieve a comparable level of knowledge regarding female-derived proteins that comprise the reproductive environment, we utilized semiquantitative MS-based proteomics to study the composition of the FRT tissue and, separately, the luminal fluid, before and after mating in Drosophila melanogaster. Our approach leveraged whole-fly isotopic labeling to delineate female proteins from transferred male ejaculate proteins. Our results revealed several characteristics that distinguish the FRT fluid proteome from the FRT tissue proteome: (1) the fluid proteome is encoded by genes with higher overall levels of FRT gene expression and tissue specificity, including many genes with enriched expression in the fat body, (2) fluid-biased proteins are enriched for metabolic functions, and (3) the fluid exhibits pronounced postmating compositional changes. The dynamic mating-induced proteomic changes in the FRT fluid inform our understanding of secretory mechanisms of the FRT, serve as a foundation for establishing female contributions to the ejaculate-female interactions that regulate fertility, and highlight the importance of applying proteomic approaches to characterize the composition and dynamics of the FRT environment.

Spermatheca of the scorpionfly Sinopanorpa tincta (Navás, 1931) (Mecoptera: Panorpidae)

The spermathecal structure of the scorpionfly Sinopanorpa tincta (Navás, 1931) was investigated using light microscopy, scanning, and transmission electron microscopy. The spermatheca consists of a bean-shaped spermathecal reservoir and an elongated spermathecal duct. The spermathecal reservoir can be subdivided into a distal portion with well-developed muscles and a proximal transitional portion connected to the spermathecal duct. The spermathecal duct is slender for its basal three-fourths and is greatly thicker for its distal one-fourth, which is mainly responsible for secretory function. A spermathecal pump formed from longitudinal muscle fibers was attached to the reservoir to control the transport of sperm. The lumen of the spermathecal reservoir is lined with a cuticle and filled with spermatozoa after copulation. The epithelium of the distal reservoir comprises a single type of epithelial cells, while the epithelium of the proximal reservoir and the spermathecal duct has three types of cells: secretory cells, duct-forming cells, and common epithelial cells. The secretory cells are rich in mitochondria, rough endoplasmic reticulum, and electron-dense secretory vesicles. The duct-forming cells form cuticular ducts, which connect the secretory cells to the lumen of the spermatheca. The spermathecal reservoir mainly serves as the storage of sperm, but the proximal reservoir as well as the spermathecal duct serves as secretory functions that maintain sperm viability.