ABSTRACT
Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs) were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.
Subject(s)
Animals , Insect Vectors/classification , Triatominae/classification , Chagas Disease/transmission , Ecosystem , Geography, Medical , Mexico , Models, Biological , Population DensityABSTRACT
Analysis of antibiosis resistance to common cutworm (Spodoptera litura Fabricius) in soybean (Glycine max (L.) Merr.) has progressed significantly, but the immediate cause remains unknown. We performed quantitative trait loci (QTL) analysis of pubescence density and plant development stage because these factors are assumed to be the immediate cause of resistance to cutworm. The QTLs for pubescence appeared to be identical to the previously detected the Pd1 and Ps loci controlling pubescence density. We found no candidate loci for flowering time QTLs, although one could be identical to the gene governing the long-juvenile trait or to the E6 loci controlling maturity. None of the QTLs overlapped with the QTLs for antibiosis resistance.