Sobre a variação intra-específica em Triatoma dimidiata (Latreille) e Triatoma infestans (Klug) (Hemiptera, Reduviidae)

Abstract

A observação de oito exemplares de Triatoma dimidiata (Latreille, 1811) de procedência diversas, com vistas a procurar caracterizar as estruturas da genitália externa dos machos (processo do endosoma, suporte do falosoma, falosoma e visica) levou-nos a constatar a mesma variabilidade que a espécie demonstra em relação aos seus caracteres externos de colorido e relações da cabeça e do rosto. Por associação de idéias, ampliamos um estudo anterior sobre a genitália masculina de Triatoma infestans (Klug, 1834), também espécie de larga distribuição geográfica, porém com caracteres externos estáveis. Encontramos assim mesmo, embora em percentagem pequena, que os espinhos do processo do endosoma, habitualmente em número reduzido, podiam não existir. Desta espécie observamos quinze exemplares, de procedências diversas.<br>The analysis of eight speciemens of Triatoma dimidiata (Latreille, 1811) of diverse origins, in order to characterize the structure of the male external genitalia (endosoma process, struts, phallosoma, vesica) led us to point out that the same variability is demonstrate by the species in relation to its external colour characters and the relation between the head and rostrum. Triatoma dimidiata is a vector of Chagas' disease in several American countries, from Mexico (extreme north of its distribution) to the north of South America, including Colombia, Venezuela, Ecuador and Peru. Similarly we have carried out a large scale study on male genitalia of Triatoma infestans (Klug, 1834) which also has a wide geographic distribution, but with stable external characters. The spines of the endosoma process which generally are few in number, might not exist in a small percentage of cases. We analysed fifteen specimens of diverse origins

Variations of the External Male Genitalia in Three Populations of Triatoma infestans Klug, 1834

“…The present work shows results in agreement with those observed by Lent and Jurberg (1985), although it has a wider scope as it includes an analysis of the representatives of three populations that presented different characteristics.…”

“…The variation of the number of the denticles in the endosoma process of T. infestans was firstly observed by Lent and Jurberg (1985), while studying 15 individuals from Bolivia, Paraguay, Chile, Argentina, Brazil and a specimen from Chaco-i in Paraguay without denticles in the endosoma process.…”

“…At present, these morphological variations of the male genitalia have not been observed in the studies covering populations. Lent and Jurberg (1985) found small differences in two structures of the male genitalia (endosoma process and phallosome support) while studying 15 specimens of T. infestans from different places, indicating the possibility that this variability could occur at a populational level. This work has the purpose of studying comparatively, for the first time, the external male genitalia of insects of different populations of T. infestans and to investigate the correlation between the morphological and behavioral variations.…”

Morphological Studies on the Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae, Triatominae) Genital Structures and Eggs of Different Chromatic Forms

“…Recently, Jurberg and Galvão (1997) used genital structures to describe a new genus in triatomines. At intraspecific level, Lent and Jurberg (1985) reported individual variations for T. infestans and T. dimidiata. The later species showed chromatic variations and their genital structures did not correlate with the distinct chromatic patterns.…”

New chromosomal evidence for the origin of Triatoma infestans populations from Brazil

“…Intraspecific variability and variation within populations have been detected by other means between T. infestans from different locations. Lent and Jurberg (1985) reported intraspecific variation in these insects by the morphological analysis of the male genital structures. Pires et al (1998) observed variation in the external structures of the genitals and suggested that this could be used as a tool to characterize the populations studied.…”