Colonization of Asia by coin spiders

Reconstructing biogeographic history is challenging when dispersal biology of studied species is poorly understood and they have undergone a complex geological past. Here, we reconstruct the origin and subsequent dispersal of coin spiders (Nephilidae: Herennia), a clade of 14 species inhabiting tropical Asia and Australasia. Specifically, we aim to answer (i) what is the sequence and chronology of coin spider dispersal from their origin to the present distribution, (ii) how would alternative dispersal biologies influence this pattern and (iii) is the unusually large range of H. multipuncta a result of human activity.

We demonstrate the importance of the understanding of organismal biology in biogeographic reconstructions. In organisms where dispersal is not well understood, we show how testing alternative modes of dispersal through parallel statistical models might prove helpful in uncovering the most likely dispersal biology without direct field observation.

Furthermore, our results show that H. multipuncta internal splits are generally too old to be influenced by humans, thereby implying its natural colonization of Asia. We speculate that coin spiders’ ancestor may have lost the ability to balloon, but that H. multipuncta regained it, thereby colonizing and maintaining larger areas.