Morphobiological aspects of Rhodnius brethesi Matta, 1919 (Hemiptera:Reduviidae) from the Upper and Middle Negro River, Amazon region of Brazil: I - scanning electron microscopy

Abstract

The occurrence of autochthonous cases of Chagas disease in the Amazon region of Brazil over recent decades has motivated an intensification of studies in this area. Different species of triatomines have been identified, and ten of these have be proven to be carriers of the parasite Trypanosoma cruzi or "cruzi-like" parasites. Studies conducted in the municipalities of Santa Isabel do Rio Negro and Barcelos, located on the Upper and Middle of the Negro River, microregion of Negro River, state of Amazonas have confirmed not only thatRhodnius brethesi is present in the palm tree Leopoldinia piassaba, but also that this insect was recognized by palm fiber collectors. A morphological study of eyes, inter-ocular and inter-ocellar regions, antennae, buccula, labrum, rostrum, stridulatory sulcus and feet, including the apex of the tibia, spongy fossette and ctenidium was conducted by scanning electron microscopy. The buccula and the stridulatory sulcus presented notable differences in specimens of different genera and also of different species. These data make it possible to suggest that the details presented in these structures can be included as diagnostic characteristics to be used in new dichotomous keys, thereby contributing towards studies of taxonomy and systematics and furnishing backing for comparative analysis of specimens collected from different localities.Key words: Rhodnius brethesi -external morphology -taxonomy -scanning electron microscopy -Amazon region -Brazil Over recent years, attention has been drawn to Chagas disease infection in the Amazon region of Brazil because of increased numbers of reports of acute cases and the presence of individuals who are serologically positive for this infection (Coura et al. 1995, 2002a, Fraiha Neto et al. 1995, Valente et al. 1999, Dias et al. 2002. So far, it is unclear whether these growing numbers of human cases are due to increased transmission or whether they are the result from an active search for positive cases. This latter is the case in the state of Pará, where greater numbers of small outbreaks attributed to contamination by oral transmission have been described (Valente et al. 1999).One of the epidemiological profiles discerned in the Amazon region that has received deserved attention is the one found in the Upper and Middle Negro River region, microregion of Negro River in the state of Amazonas. Initial investigations by Coura et al. (1994Coura et al. ( , 1995 indicated that the presence of human infection in areas of the Negro River were associated with extractive activities relating to the collection of fiber from the native palm tree Leopoldinia piassaba Wallace, 1853. The link in the transmission cycle was pinpointed as the contact between the fiber gatherer and the species of triatomines present in the extraction areas (Coura et al. 2002a). The data obtained though that investigation showed that two vector species were present in the extraction areas: Rhodnius brethesi Matta, 1919, and Panstrongylus geniculatus (Latreille, 1811). The first of th...

Morphological Aspects of Antennal Sensilla of theRhodnius brethesiMatta, 1919 (Hemiptera: Reduviidae) from the Negro River, Amazon Region of Brazil

“…The third and fourth segments are fully lined with bristles II, thin-walled sensilla (thin-walled), thick-walled (thickwalled), basiconica (Figure 3(a)), and coeloconic (Figure 3(d)), all types already described for Triatominae [9,12,13,21,24,25].…”

“…These types of sensilla are already described for Triatominae [9,12,13,21,24,25]. However, the latter are only seen in studies with Rhodnius species [9,24], suggesting that lamellar-based trichobothria sensilla are a synapomorphic feature of the genus [4]. Another interesting observation, which was not mentioned in previous studies, is that these sensilla are only seen on the dorsal surface of the second antennal segment.…”

“…Still in the second antennal segment, there is a row of trichobothria sensilla (Figure 2(a)) with a cuticular area at the base in the form of short extensions and lamellar structures (Figures 2(d) and 2(e)). These types of sensilla are already described for Triatominae [9,12,13,21,24,25]. However, the latter are only seen in studies with Rhodnius species [9,24], suggesting that lamellar-based trichobothria sensilla are a synapomorphic feature of the genus [4].…”

Bioactivity of the latex from Parahancornia amapa (Apocynaceae) on the development of Rhodnius nasutus (Hemiptera, Reduviidae, Triatominae) under laboratory conditions

“…Morphological alterations of the adults from the test groups were analyzed using scanning electron microscopy (SEM), as described by Santos-Mallet et al (2005). The statistical program used to analyze the data was GraphPad InStat.…”

Mosaico de vulnerabilidades: açaí artesanal e risco da transmissão oral da doença de Chagas

“…Envolvendo triatomíneos (conhecidos pela população local como piolho de piaçava) -com destaque para o Rhodnius brethesi -alojados em palmeiras Leopoldinia piassaba. A respeito, veja-se:Albajar et al (2003); Brum-Soares et al (2010); Coura, Barrett e Naranjo (1994);Coura et al (1999Coura et al ( , 2002aCoura et al ( , 2013aCoura et al ( e 2013b;Duncan, Malheiro e Danilow (2015);Santos-Mallet et al (2005); Souza (2013) e Xavier et al(2006).…”