Microhabitat change drives diversification in pholcid spiders
(Published in BMC Evolutionary Biology; https://doi.org/10.1186/s12862-018-1244-8)
Pholcid spiders occur is a wide variety of microhabitats, and field observations have suggested that this microhabitat diversity may be causally related to species diversity. In this study we investigate the influence of microhabitat on diversification rates in pholcid spiders. Diversification analyses were conducted in the framework of the largest molecular phylogeny of pholcid spiders to date based on three nuclear and three mitochondrial loci from 600 species representing more than 85% of the currently described pholcid genera.

Assessments of ancestral microhabitat revealed frequent evolutionary change. In particular, within the largest subfamily Pholcinae, numerous changes from near-ground habitats towards leaves and back were found. In general, taxa occupying leaves and large sheltered spaces had higher diversification rates than ground-dwelling taxa. Shifts in speciation rate were found in leaf- and space-dwelling taxa.

Our analyses result in one of the most comprehensive phylogenies available for a major spider family and provide a framework for any subsequent studies of pholcid spider biology. Diversification analyses strongly suggest that microhabitat is an important factor influencing diversification patterns in pholcid spiders.

The three main microhabitats in pholcid spiders: life leaves, large sheltered spaces, and leaf litter. Drawing: J. Eberle.