Reproductive Biology of Triatoma brasiliensis (Hemiptera, Triatominae) During the Imaginal Molt

Abstract

Abstract. The triatomines are vectors of the protozoan Trypanosoma cruzi, etiologic agent of Chagas disease. These insects are sexually active after the imaginal molt. Some aspects have been studied in Triatoma brasiliensis during the imaginal molt, such as autogeny in virgin females and the relationship between blood ingestion by fifth instar nymph and the realization of the imaginal molt. Thus, to aid in the understanding of reproductive biology and developmental physiology of these vectors, this article analyzes the spermatogenesis of T. brasiliensis during the imaginal molt. The analysis of the seminiferous tubules from males in the fifth instar during imaginal molt has demonstrated that T. brasiliensis has only a few spermatids and a plentiful quantity of sperm. Thus, we suggest that during imaginal molt the cell division is disrupted aiming to reduce energy costs and the differentiation into sperm is stimulated to ensure the paternity of the adult male.

Dichotomous Keys Based on Cytogenetic Data for Triatomines Reported in Brazilian Regions with Outbreaks of Orally Transmitted Chagas Disease (Pernambuco and Rio Grande Do Norte)

“…Cytogenetic studies have provided insight into reproductive [39][40][41], physiological [42,43], evolutionary [44][45][46], systematic [34,47], and taxonomic [33,36,48] aspects of Triatominae. Cytotaxonomy was initially developed in 1950, when Schreiber and Pellegrino [49] described some karyotypes of species from South America.…”

Nucleolar Persistence: Peculiar Characteristic of Spermatogenesis of the Vectors of Chagas Disease (Hemiptera, Triatominae)

“…Furthermore, the spermatogenesis of the triatomines is characterized as cystic, 5,6 and it has been suggested that, during imaginal molt (transition from the fifth instar nymph to adult), the cell division is disrupted, aiming to reduce energy costs, and the differentiation into sperm is stimulated to ensure the paternity of the adult male. 7 In 1999, Tartarotti and Azeredo-Oliveira, 8 while studying the spermatogenesis of Panstrongylus megistus and Panstrongylus herreri (= Panstrongylus lignarius), noted that these triatomines exhibited a different nucleolar behavior than the one described for other eukaryotes: the nucleolus persisted during all stages of meiosis. The authors characterized this phenomenon as nucleolar persistence.…”