Morphological and developmental plasticity in larvae of Physalaemus santafecinus (Anura: Leiuperidae) in response to chemical cues of different predators

GÓMEZ, VALERIA I.; KEHR, ARTURO I.

PHYLLOMEDUSA

DEPARTAMENTO DE CIENCIAS BIOLOGICAS ESALQ-USP

Año: 2011 vol. 10 p. 143 - 151

1519-1397

Many antipredator responses are mediated or induced by the hability of the prey to identify chemical cues of predators. The presence of chemicals produced by predators may alert tadpoles to the presence of the predators and a heightened response to alarm cues or the predators presence may increase the posibility of prey survival. We examined changes on morphology and growth and development rate of Physalaemus santafecinus tadpoles reared in the presence of chemical cues of water beetles (Hydrophilidae) and a fish (Characidae). We recorded the time to metamorphosis, as well as weights of metamorphic individuals to determine if the larval stages is accelerated. The experiments were performed under microcosm conditions, with three treatments-chemical cues from fish, water beetles, and a control group. each treatment was replicated 30 times. To obtain independent data for different variables, treatments were conducted on individual larvae in separate containers. The principal results were, as follow.1) Larval morphology were significantly affected by the presence of a predator. 2) Control tadpoles were significantly larger that those subjected to the other two treatment (cues of water beetle and fish). 3) Growth and development rates did not differ significantly among any treatment. 4) Neither time to metamorphosis nor weights of metamorphs varied significantly among treatments. Our results suggest that tadpoles are able to perceive predators by chemical cues released in the water, and P. santafecinus tadpoles alter their morphology to chemical cues that indicate predation. However chemical cues of  predators had not detectable effect on growth rate and developmental rates of these tadpoles