The ecotopes and evolution of triatomine bugs (triatominae) and their associated trypanosomes

Abstract

cruzi 1 (Z1) by host transfers into rodents, edentates, and primates. We have constructed a molecular phylogeny of haematophagous vectors, including triatomine bugs, which suggests that faecal transmission of trypanosomes may be the ancestral route. A molecular clock phylogeny suggests that Rhodnius and Triatoma diverged before the arrival, about 40 million years ago, of bats and rodents into South America.Key words: triatomine bugs -ecotopes -palms -Rhodnius -marsupials -Didelphis -edentatesTrypanosoma cruzi -evolution -phylogenetics Phenotypic diversity and genotypic diversity of Trypanosoma cruzi were described in a series of publications in the 70s and 80s. At least two major subdivisions within the species were defined, initially as principal zymodemes (reviewed in Stothard et al. 1999, Anon 1999. Contemporary papers on T. cruzi in the Amazon basin of Brazil, described the habitats and vertebrate hosts of triatomine bug species and their roles as vectors of T. cruzi and T. rangeli (Miles et al. 1981a(Miles et al. ,b, 1983). Here we revisit these early studies in the context of (a) more recent molecular approaches to understanding T. cruzi genotypes, and (b) new research on the phylogeny of triatomine bugs. We speculate on the evolution of triatomine bugs and T. cruzi, and provide evidence for key elements of their evolutionary history.

Ecological aspects of Rhodnius nasutus Stål, 1859 (Hemiptera: Reduviidae: Triatominae) in palms of the Chapada do Araripe in Ceará, Brazil

“…as in the original species description according to Lent and Wygodzinsky (1979), while those in the other palm species were chestnut-coloured. Gaunt and Miles (2000) suspected that variation in triatomine colour patterns, particularly those of certain Rhodnius species, may be influenced by habitat (e.g., the palm species on which they occur). Our field observations support this theory, as colouration of R. nasutus (nymphs and adults) corresponded exactly to that of the stems and base of the fronds, providing camouflage for the insects.…”

Trapping Triatominae in Silvatic Habitats

“…The study of these habitats by means of traditional approaches (random manual searches and dissection) is laborious and destructive, hampering the development of more detailed studies. Hence, many of the characteristics of triatomine habitats are often obscure and remain to be more thoroughly investigated (Romaña et al 1999, Gaunt & Miles 2000. Livebaited adhesive traps could help overcome some of these problems.…”

Two Hybridization Events Define the Population Structure of Trypanosoma cruzi

“…Broadly, DTU I is associated with the silvatic cycle of transmission and arboreal mammals; DTU II is associated with the domestic cycle and a terrestrial niche (Miles et al 1978;Fernandes et al 1998;Zingales et al 1998;Yeo et al 2005) and associated triatomine vectors (Gaunt and Miles 2000) in Brazil and other South American countries. This association may vary by region and as the human population encroaches upon the silvatic ecosystem.…”