Preliminary Results on the Genetic Control of Dispersal in Common Frog Rana temporaria Froglets

Abstract

Post-metamorphic dispersal in the common frog Rana temporaria (Amphibia, Anura) was studied with a combination of field (pit-fall traps) and laboratory (arena, artificial crossing) experiments. In the first studied population, the breeding place was surrounded by lines of fence-pitfall traps allowing capture of dispersing froglets. Dispersal was at random on the edge of the pond, but oriented in the most favorable terrestrial habitat at 10 m from the edge. Froglets of this population were then tested in orientation arena built on the University campus, where they also dispersed at random. The two other studied populations reproduced at each side (north and south) of a lake. Froglets from each population were tested in similar orientation arena, where they did not dispersed at random but to the north and south direction respectively. In the laboratory we crossed males and females originated from these two populations. Resulting crossed froglets exhibited variable dispersal patterns, which significantly differed from those observed with their respective parents. These results argued for an at least partly genetic control of emigration direction in these two frog populations, that we interpreted as the result of directional selection due to landscape change during the XXth century.