Reassessing the phylogenetic position of the epizoic earwigs (Insecta: Dermaptera)

• There are two independent origins of epizoic lifestyle within Dermaptera.
• Hemimerida and Arixeniidae are derived from different lineages of Spongiphoridae.
• Analyses suggest that viviparity evolved prior to the shift to an epizoic lifestyle.

Dermaptera is a relatively small order of free-living insects that typically feed on detritus and other plant material. However, two earwig lineages – Arixeniidae and Hemimeridae – are epizoic on Cheiromeles bats and Beamys and Cricetomys rats respectively. Both of these epizoic families are comprised of viviparous species. The monophyly of these epizoic lineages and their placement within dermapteran phylogeny has remained unclear. A phylogenetic analyses was performed on a diverse sample of 47 earwig taxa for five loci (18S rDNA, 28S rDNA, COI, Histone 3, and Tubulin Alpha I). Our results support two independent origins of the epizoic lifestyle within Dermaptera, with Hemimeridae and Arixeniidae each derived from a different lineage of Spongiphoridae. Our analyses places Marava, a genus of spongiphorids that includes free-living but viviparous earwigs, as sister group to Arixeniidae, suggesting that viviparity evolved prior to the shift to the epizoic lifestyle. Additionally, our results support the monophyly of Forficulidae and Chelisochidae and the paraphyly of Labiduridae, Pygidicranidae, Spongiphoridae, and Anisolabididae.

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