Aquatic habitat size induce changes in ecological features of Physalaemus albonotatus tadpoles.

GÓMEZ, VALERIA I.; KEHR, ARTURO, I.

Gramado

Congreso; 7mo Congreso Brasilero de Herpetología; 2015

Sociedad brasilera de herpetología

Habitat size has important effects on population and community process. Until now, the influence of aquatic habitat shape on the growth and development on tadpoles has received slightly attention. Understanding these effects is important to achieving optimal conditions for raising in artificial environments as well as understanding how the physical shape of the environment influences the animals in the wild. We studied Physalaemus albonotatus tadpoles. Our goal were detect responses to variation in surface area and water volume by traits correlated with fitness and determine if habitat-size effects are constant over the larval period. Tadpoles from six P. albonotatus foam nests were reared individually under microcosms conditions in plastic containers of different size filled with 200 y 400 ml of well water. The experiment consisted in a 2 x 2 factorial design; two volume of water (high and low) and two surfaces area (small and large). The experiment started with tadpoles on development stage 26 (Gosner) and finished when tadpoles metamorphosed. At 15 and 30 days of start the experiment, tadpoles were measured, weighed and staged following Gosner (1960). Tadpoles were photographed for morphological measurement (body length, body height, tail length, tail height, and caudal muscle height). We also recorded timing and weight at metamorphosis. Morphological traits were analyzed using multivariate analysis of covariance (MANCOVA) with a subsequent ANOVA and his corresponding test a posteriori. We found that at 15 days tadpoles reared at high volume of water significantly increased all morphological variables, as well as weight and development stage in relation to tadpoles reared at low volume of water. We found no difference in tadpoles reared at different surface. At 30 days, tadpole reared at small surface significantly increased the body length, body height and developmental stage in relation to tadpoles reared at large surface. We found no difference in tadpoles reared at different volume of water. Tadpoles reared at small surface reach metamorphosis significantly earlier in relation to tadpoles reared at large surface. This study demonstrates that habitat size can elicit changes in morphology, growth and development of tadpoles and the response to habitat size can change during development.