sábado, 8 de novembro de 2014

The application of Bergmann's Rule to Carollia perspicillata Linnaeus 1758 (Mammali, Chiroptera)

BARROS, L.A.V.; FORTES, R.R.; LORINI, M.L. 2014. The application of Bergmann's Rule to Carollia perspicillata Linnaeus 1758 (Mammali, Chiroptera). Chiroptera Neotropical 20(1):1243-1251.

Abstract. Bergmann’s Rule describes the association between body size of species and latitude. The proposed mechanism to explain the pattern would be the lowest surface/volume ratio found in large animals, which should result in an energy advantage in cold environments. The present study tested to what extent this pattern can be applied in bat populations of Carollia perspicillata (Linnaeus, 1758). We used secondary data, taken from the collection of Universidade Federal Rural do Rio de Janeiro (UFRRJ) and raw data provided by researchers, covering a latitude gradient ranging from 23º03' S to 0º10' N, at altitudes ranging from 10 to 1093m above sea level. Climatological data were obtained from the website of Instituto Nacional de Meteorologia (INMET). Body size analyses were based on mean and maximum length of forearm and body mass, and carried out through latitude, altitude and temperature gradients. A total of 488 adult specimens were analyzed, summarizing data for 23 localities. Body size variables showed a decrease toward higher latitudes and higher altitudes, and an increase in relation to increasing temperature. The results partially follow an inverse trend of the original proposal, called Bergmann’s Rule "converse". Bats’s wings are highly vascularized naked membranes, making their surface/volume ratio higher than that of other animals of similar size; thus a large body size would in fact result in bigger ratios and greater heat loss. The low values of all explicability indexes (R²) and linear coefficients (β) suggest that geographical variation in a  species’ morphology cannot be only explained on the basis of latitudinal clines.

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