Using ecophysiological traits to understand the Realized Niche: the role of desiccation tolerance in Chagas disease vectors

DE LA VEGA, G.J.; SCHILMAN, P.E.

OECOLOGIA

SPRINGER

Lugar: Berlin; Año: 2017 vol. 185 p. 607 - 618

0029-8549

Small ectotherms, such as insects, with high surface-area to volume ratios are usually at risk ofdehydration in arid environments. We hypothesize that desiccation tolerance ininsects could be reflected in their distribution, which is limited by areaswith high relative values ​​of water vapor pressure deficit (VPD) (e.g. hot and dry). The main goal of thisstudy was to explore whether incorporation of eco-physiological traits such asdesiccation tolerance in arid environments can improve our understanding of speciesdistribution models (SDM). We use a novel eco-physiological approach tounderstand the distribution and the potential overlap with their fundamentalniche in triatomine bugs, Chagas disease vectors. The desiccation dimension forT. infestans, T. delpontei, T. dimidiataand T. sordida niches seem to extendto very dry areas. For T. vitticeps,xeric areas seem to limit the geographical range of their realized niche. Themaximum VPD limits the western and southern distributions of T. vitticeps, T. delpontei and T. patagonica. All species showed hightolerance to desiccation with survival times (35°C-RH~15%) ranging from 24-38days, except for T. dimidiata (9 days),which can be explained by a higher water loss rate, due to a higher cuticularpermeability along with a higher Critical Water Content. This approachindicates that most of these triatomine bugs could be exploiting the drynessdimension of their fundamental niche. Incorporating such species-specifictraits in studies of distribution, range, and limits under scenarios ofchanging climate could enhance predictions of movement of disease-causingvectors into novel regions.