Oviparity, viviparity or plasticity in reproductive mode of the olm Proteus anguinus: an epic misunderstanding caused by prey regurgitation?

What is it about?

The reproduction of cave animals remains largely unknown. Theory predicts that in stable environments - such as caves - live-bearing (viviparity) is favoured over egg-laying (oviparity). The olm (Proteus anguinus), one of the largest living cave animals, has been suggested to be either live-bearing, egg-laying, or both in the past. Olm viviparity had also been reported by Paul Kammerer, who was accused of data falsification in the early 20th century. With the rise of epigenetics and phenotypic plasticity and their role in evolution, interest in Kammerer’s experiments have reawakened. However, all recent observations suggest that olms reproduce by egg-laying. Here we show data of olms feeding and regurgitating salamander larvae in a spring that had been previously reported to contain live-bearing olms. We suggest that the regurgitation of salamander larvae led to the false conclusion that they are live-bearing, and therefore provide additional support that reports on live-bearing reproduction in olms are doubtful.

Featured Image