Meeting Abstract

P1.143  Friday, Jan. 4  Can the thermal conditions experienced during ontogeny have consequences on phenotypic flexibility in Phyllotis darwini? CAVIERES, G*; NUñEZ-VILLEGAS, M; SABAT, P; Universidad de Chile; Universidad de Chile; Universidad de Chile griselcavieres@gmail.com

We studied the putative effect of thermal history experienced during development on physiological flexibility of energetic traits (basal metabolic rate (BMR), thermal conductance (Ct) and body mass) in an altricial rodent, the leaf-eared mouse (Phyllotis darwini). Adults individuals were trapped in central Chile and maintained in pairs for breed. Pups were isolated after weaning and acclimated to either cold or warm conditions (15 and 30° C) until adulthood. Subsequently, individuals were acclimated to opposite thermal treatment. The results revealed a significant effect of the ontogenetic history on adult’s thermoregulatory capacities. Individuals developed at 15°C showed a significant increase in BMR. Additionally, individuals reared at 30 ° C exhibited lower BMR, and a Ct significantly higher, which in turn was correlated with an increase in morphometrics traits related to heat loss (foot and ear length). Adults acclimated at 30°C decreased BMR; however those reared at 30°C and then acclimated to 15°C did not increased BMR. Furthermore, the Ct in animals developed at 30 ° C changed when they were re-acclimated at 15 ° C, but not in the opposite direction. Therefore, morphometric traits showed inflexible reaction norms. The results suggest the existence of ontogenetic dependence on the ability of change on metabolic attributes in Phyllotis darwini.