From larval stage to adulthood? Habitat type-specific chemical fingerprints of fire salamander larvae might give first indication for adult mate preference

Assortative mating can play a major role in the divergence of a population with gene flow. In a fire salamander population near Bonn, Germany, the larvae differ genetically according to the habitat type they are found in, i.e. ponds or streams. Neither sound nor vision are a source for assortative mating in fire salamanders, but it is known that females can discriminate between sexes and habitat types of the males based on chemical cues. The adults share the same terrestrial habitat which leads to the question whether there is a habitat type-specific chemical fingerprint already existing in the larvae that may be used in the adult stage as the base for assortative mating. We took water samples and captured larvae at two ponds and two streams and used polydimethylsiloxane and TD-GC-MS to collect and analyze samples of the environmental background as well as from the surface of the larvae. We found a significantly different composition of chemical features in the environmental back-ground samples. Additionally, we found the larvae to carry habitat type-specific chemical features. These finding allow to speculate that the features on the larval surface may be used