Geometric morphometrics and ecological niche modelling for delimitation of near-sibling triatomine species

Abstract

Identifying morphologically similar triatomine species is key to Chagas' disease vector control and surveillance, but remains challenging when only qualitative phenotypic data are available. We investigated whether morphometric and ecological variation can provide additional criteria for species delimitation by combining geometric morphometrics and ecological niche modelling to characterize two near-sibling triatomine species, Triatoma sordida and Triatoma garciabesi (Reduviidae: Triatominae). We analysed size and shape variation in 231 wings and 123 heads from one T. garciabesi and three T. sordida populations. Predicted distribution maps (21 climatic variables, 324 vector occurrence points) were produced using the Maxent method. Multivariate analyses summarized morphological and ecological variation. Wings and heads of T. sordida were significantly larger and more elongated than those of T. garciabesi. Discriminant analyses separated the species, with a partial overlap between Argentinean populations. The predicted distribution of T. garciabesi included northwest Argentina (mainly arid Chaco), whereas that of T. sordida included northeast Argentina (humid Chaco) and the Brazilian Cerrado and Caatinga ecoregions. Clear ecological niche differences were observed, with T. garciabesi occupying colder and drier areas than T. sordida. Our results show how morphometric variation and niche divergence can be used to enhance operational criteria for the delimitation of phenotypically similar triatomine species.

Synanthropic triatomines (Hemiptera, Reduviidae) in the state of Pernambuco, Brazil: geographical distribution and natural Trypanosoma infection rates between 2006 and 2007

“…Despite these differences, the co-occurrence of R. neglectus and R. nasutus in some states in the Northeast Brazil, including Pernambuco, was predicted 40 . Our results confirm these predictions and reinforce the idea that the identification of these species in these areas must be made with the aid of morphometric [41][42] and molecular methods 43 due to morphological similarities between these species. Finally, the sporadic occurrence of these species of Rhodnius in Pernambuco should be associated with the presence of palm trees in the peridomiciles.…”

Climatic factors influencing triatomine occurrence in Central-West Brazil

“…sordida and R. neglectus were the species showing the broadest geographic distributions in CW. Both species are capable of adapting to different ecosystems, as has been noted by other authors (Lent & Wygodzinsky 1979, Forattini 1980, Gurgel-Gonçalves & Cuba 2009, Gurgel-Gonçalves et al 2011, 2012b. Although it is the most frequently encountered species in Brazil, T. sordida occurs mainly in peridomicile areas and generally feeds on birds, which reduces the probability of vectorial transmission of T. cruzi to humans (Diotaiuti et al 1993).…”

“…A greater number of synanthropic triatomine species was observed in areas with greater seasonal temperature variation. Other studies have shown temperature to be an important determinant of the distribution of triatomines on a regional or continental scale (Gorla 2002, Rodriguero & Gorla 2004, Batista & Gurgel-Gonçalves 2009, Gurgel-Gonçalves & Silva 2009, Gurgel-Gonçalves et al 2011). However, other environmental variables, such as the slope of the terrain (Leite et al 2011) and humidity (Arboleda et al 2009), have also been identified as principal determinants of the occurrence of certain species.…”

Análise preditiva da distribuição geográfica de hantavírus no Brasil

“…Estes modelos de predição já foram utilizados para analisar a distribuição de algumas doenças como peste (Neerinckx et al 2008, Giles et al 2011, febre do Nilo (Wimberly et al 2003, Peterson et al 2008a), influenza aviária (Kilpatrick et al 2006) e febre hemorágica de Marburg . Além disso, a MNE tem sido aplicada para analisar a distribuição de vetores de doenças tropicais como doença de Chagas (Peterson et al 2002, Lopez-Cardenas et al 2005, Gurgel-Gonçalves & Cuba 2009, Gurgel-Gonçalves et al 2010, Pereira et al 2013, malária (Levine et al, 2004a, Levine et al 2004b, Moffett et al 2007), dengue , doença de Lyme (Brownstein et al 2003) e leishmaniose (Peterson & Shaw 2003, Donalisio et al 2012 .…”