Testing the interplay between physiological and life-history traits: an experimental study in Drosophila

GUILLERMO FOLGUERA; JOSÉ LUIS MUÑOZ; SANTIAGO CEBALLOS; FRANCISCO BOZINOVIC ; ESTEBAN HASSON

Evolutionary Ecology Research

Evolutionary Ecology

Año: 2007 p. 1211 - 1222

1522–0613

Question: Developmental time and metabolic rate are correlated at higher levels of organization. Does this allometric relationship scale down to the intraspecific level? Methods: We exposed flies of three species of Drosophila collected at contrasting altitudes and similar latitudes to varying experimental thermal regimes. Metabolic rate was measured as CO2 production using a ‘closed systemÂ’. Developmental time was estimated as the time elapsed from the first instar larval stage until adult emergence. Results: We observed a positive correlation between metabolic rate and developmental time among species. However, such allometry was not detected within species. Interestingly, both variables presented different patterns of interactions with sex and thermal treatment. Conclusions: It may not be possible to extrapolate allometric rules of macroecology towithin-species variation. Indeed, the factors that affect variation in physiological variables at the intraspecific and interspecific levels should be different. Keywords: developmental time, Drosophila, metabolic rate, thermal adaptation.