Morphometry and morphology of the antennae of Panstrongylus megistus Burmeister, Rhodnius neglectus Lent, Rhodnius prolixus Stal and Triatoma vitticeps Stal (Hemiptera: Reduviidae)

Abstract

) for all fi ve instars. The morphological study of the second antennal segment by scanning electron microscopy (SEM) disclosed that the fi rst instars of all four species exhibit type I bristles sensillae and one trichobothrium. Another type III bristle and basiconic, campaniform, coeloconic, trichoid sensillae and type I bristle and trichobothria were noted on their fourth instars and adults. Campaniform sensillae were noted only on T. vitticeps adults. Nodules were observed in the joint between 1 st and 2 nd antennal segments of adults of P. megistus and T. vitticeps, but not on R. neglectus and R. prolixus.KEY WORDS: Triatominae, mensuration, electron microscopy, sensilla The Chagas' disease, which is caused by the fl agellate protozoan parasite Trypanosoma cruzi, is widespread in North and South America from Mexico to southern Argentina and Chile, and is still considered a major public health issue in Latin America (WHO 2005). Great advances have been made in the reduction of vectorial and transfusional transmission, with a resulting alleviation in the incidence of Chagas' disease. Yet, it is estimated that a total of 18 million individuals are still infected in 17 Central and Latin American countries. Approximately 93 million people live in the endemic areas, and 200,000 new cases occur annually in these areas (WHO 2005).Panstrongylus megistus Burmeister was fi rst recorded to transmit T. cruzi in 1909T. cruzi in (Chagas 1909, and is one of the six major species vectoring the Chagas' disease (Silveira 1983, Dias 1993, Brazilian Health Ministry 2005. Rhodnius neglectus Lent plays a secondary role in transmitting the disease; however, it is widespread in the Brazilian states of Bahia, Goiás, Mato Grosso, Maranhão, Minas Gerais, Paraná, Pernambuco and São Paulo (Silveira 1983, Galvão et al 2003. Rhodnius prolixus Stal can be found in 16 Latin American countries and is an important vector of T. cruzi, especially in Venezuela, Colombia and French Guiana (Lent & Wygodzinsky 1979, Galvão et al 2003). Even though Triatoma vitticeps Stal is considered the most important vector in Bahia, Espírito Santo, Minas Gerais and Rio de Janeiro, studies on this species are very scarce (Galvão et al 2003).Despite the fact that immatures also play an important role in the transmission of the Chagas' disease, there are very few information on their morphology. In an early article presented by Rangel (1979) some morphological aspects of the anatomy of the digestive apparatus of P. megistus nymphs are mentioned and distinct features of nymph instars are presented in other studies (Côrrea 1954, Ramírez-Pérez 1969, Carcavallo et al 1978, Lent & Wygodzinsky 1979,Jimenez & Fuentes 1981, Brewer et al 1981, Gonçalves et al, 1985, Rosa et al 1992a, 1992b, 1995, 2000, Rosa & Barata 1997, Galvão et al 2005.Rosa st . March -April 2010 Neotropical Entomology 39(2) 215The importance of the study of the morphological traits of triatomine vectors, beyond their physiological importance as reported by Wigglesworth & Gillett (1934), Chaika (19...

Description of Rhodnius marabaensis sp. n. (Hemiptera, Reduviidae, Triatominae) from Pará State, Brazil

“…This relative length pattern of the four antennal segments is the same as the pattern observed by Rosa et al (2010) in Rhodnius neglectus and Rhodnius prolixus adults; however, the differences in size between the largest and the smallest segments are distinct: the second antennal segment of Rhodnius marabaensis sp. n. is 10.3 times larger than the first; in Rhodnius prolixus , it is 6.2 times larger, and in Rhodnius robustus it is 8.3 times larger (Table 1).…”

Immature Instars of Three Species of Rhodnius (Hemiptera, Reduviidae, Triatominae): Morphological and Morphometric Studies

“…The patterns identi ed in R. neglectus and R. prolixus were the same found for R. prolixus and R. robustus in this work. Rosa et al [28] measured the antennal segments of T. rubrovaria (Blanchard, 1843) and found patterns different from R. marabaensis, R. prolixus and R. robustus, but similar to those observed in P. megistus by Rosa et al [41]. However, in relation to the relative length of the four antennal segments, it is not possible to differentiate the studied species.…”

“…However, in relation to the relative length of the four antennal segments, it is not possible to differentiate the studied species. The different results were described for R. colombiensis, R. ecuadoriensis, R. milesi, R. stali [40] and R. neglectus [41], T. rubrovaria [28], P. megistus, and T. vitticeps [41]. Furthermore, our data show that R. prolixus and R. robustus are like R. neglectus [41] and can be distinguished from R. colombiensis, R. ecuadoriensis, R. milesi, and R. stali [40] as well as T. rubrovaria [28], P. megistus, and T. vitticeps [41] for this characteristic.…”

Third record of Rhodnius amazonicus and comparative study with R. pictipes (Hemiptera, Reduviidae, Triatominae)

“…Eighteen characters of ten females and sixteen characters of ten males of R. pictipes (Table 1) were analyzed, as well as, seventeen characters of the female specimen and thirteen characters of the male specimen of R. amazonicus, in view of the absence of antennal segments (Rosa et al, 2010;Souza et al, 2016). Length and opercular opening of two eggs of R. amazonicus and thirty eggs of R. pictipes were measured ( Table 1).…”

“…A,B and C-R. amazonicus; D,E and F-R. pictipes. Gc8: gonocoxiteVIII; Gp8: gonapophysis VIII; VII, VIII, IX: esternites; X: segment(Rosa et al, 2010).…”