Reproductive choices lead tadpole survival in Lepidobatrachus llanensis and Pleurodema guayapae

Abstract

Selection of breeding habitats represents one of the most effective ways in which anurans can offer advantages for offspring survival. In arid environments tadpoles developing in ephemeral pools face different risks for survival such as pond drying, predation, high levels of salinity, and exposure to high temperatures. Therefore, in these environments adults should actively select ponds with biotic and abiotic attributes that favor tadpole survival. In this work, we evaluate whether two frog species inhabiting halophytic shrublands from Dry Chaco (Pleurodema guayapae and Lepidobatrachus llanensis) select pond attributes for reproduction and whether selection favors the success of tadpoles on reaching metamorphosis. We recorded the use/non-use of ephemeral pools for reproduction in both species and measured five pond attributes to detect selection of breeding sites. Next, we monitored a subset of sites used for reproduction in each species in order to relate metamorphosis success with the same pond attributes. The results showed that L. llanensis selected ponds with particular attributes, while P. guayapae laid its eggs in any available pond, even ponds that dried prior to metamorphosis. Using any pond available in multiple reproductive events together with the remarkably fast development of tadpoles could actually be a strategy to effectively deal with stochasticity in rain frequencies after the formation of ephemeral ponds.