Fire salamander larvae show habitat type-specific surface chemical fingerprints

In a fire salamander population near Bonn, Germany, fire salamander females use two different habitats for larval deposition, i.e. ponds or streams. As it is known that females can discriminate between sexes and habitat types of the males based on chemical cues, we asked whether larvae show habitat specific differences in their surface chemical fingerprints. We took water samples and captured larvae at two ponds and two streams; we used polydimethylsiloxane and TD-GC-MS to collect and analyze samples of the environmental background (i.e. features that were found in the water) as well as from the surface of the larvae. We found a significantly different composition of chemical features in the environmental background 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, if retained across metamorphosis, may be used for assortative mating in the adults, which should be further investigated.