A test of multiple climate-based hypotheses for distribution limits of the Andean darkling beetles (Coleoptera: Tenebrionidae)

CARRARA RODOLFO; PERI PABLO; FLORES GUSTAVO ERNESTO

Simposio; Fourth International Tenebrionoidea Symposium; 2015

Several hypotheses related climatic variables as limiting factors of insectdistribution ranges: the ?energy?availability hypothesis? posits thatare high and low temperatures, the ?water?availability hypothesis?,posits that is low precipitation and both ?energy?variabilityhypothesis? and ?water?variability hypothesis? posits that is highseasonal variation in temperature and precipitation, respectively. Inthis work we use occurrence data of 23 endemic tenebrionids from theAndean region to assess to what extent the different climatic variableslimit their distribution ranges. First, we utilize maximum entropymodeling to evaluate the fit to data of 14 candidate models, whichresulting from the combination of different hypotheses, by applyingAkaike Information Criterion (AIC). Then, from best fitting modelto each species we conduct analyses between species probabilitiesof occurrence and climatic variables to recognize its role as limitingfactors of species distributions. Results demonstrated that speciesdistributions, as a whole, are better explained by the action of morethan one climatic variable, with the exception of one species. From23 species only 10 showed that climate act as limiting factor of theirdistribution ranges. Among climatic variables those representingwater variability were identified as the most influential for speciesdistribution ranges, followed by water availability, energy availabilityand energy variability. Considering hypotheses formulations, onlyrelationships between water availability and distribution rangesresponded according to expectations by limiting species distributiontoward low precipitations; instead, the remaining relationshipsresponded contrary to expectations limiting species distributionstoward low energy availability, and water and energy variability. Thisresult suggests that, far of generalities, different climatic variables canact as limiting factor of species distribution ranges probably due to theevolutionary history of each species