Preliminary observations on male reproductive behavior in a population of Italian tree frog (Hyla intermedia) in central Piedmont

In many lek-breeding species, male reproductive success depends both on the quality of the ornaments and on the time spent at the breeding site (attendance): males who spend more nights at the site mate more often. This study focuses on a small population of Italian tree frog (Hyla intermedia), a lek breeding Anuran, and investigates: i) the biotic and abiotic factors that affect the number of males at the lek in a given night, and ii) male mating success and the factors that influence it. During the 2013 breeding season, male tree frogs have been individually marked and recorded. For each evening we counted the males at the site and measured several environmental parameters (water temperature, air temperature, relative humidity, wind velocity and daily total rainfall). In addition, we weighed and measured males, calculated their condition index and counted the number of nights spent at the breeding site and the number of matings obtained. The number of males at the breeding site showed four peaks during the breeding season and was influenced by both abiotic (wind velocity, rainfall) and biotic factors (number of males at the site during the previous evening). Male reproductive success was not random and was positively influenced by body weight and attendance. The results of this study thus confirm that in Hyla intermedia (as in many other Hylids) endurance rivalry is an important form of competition between males and plays an important role in determining male reproductive success.