Phylogenomics changes our understanding about earwig evolution

Abstract

Earwigs are one of the comparatively species-poor insect orders. Although various aspects of the phylogeny of this lineage are poorly understood, before the present study, there was a general consensus that Dermaptera comprises two major lineages: the paraphyletic Protodermaptera or 'lower earwigs' and the monophyletic Epidermaptera or 'higher earwigs', which are nested within the former. Our phylogenomic study based on the analysis of 3247 nuclear single-copy genes reverses these relationships by placing monophyletic Protodermaptera within paraphyletic Epidermaptera. This phylogenetic reversal among the major earwig lineages is not contradicted by morphological arguments but results in far-reaching reinterpretations of the dermapteran ground plan. Within Dermaptera, Apachyidae form the sister group to the remaining earwigs which might imply that social behaviour is not part of the earwig ground plan. Our results corroborate the monophyly of Eudermaptera within Epidermaptera and the paraphyly of several traditional families. The monophyly of Protodermaptera is supported by molecular and morphological evidence, although the exact position of Karschiellidae which were not included in the molecular dataset cannot be determined.

The First Mitochondrial Genomes of the Family Haplodiplatyidae (Insecta: Dermaptera) Reveal Intraspecific Variation and Extensive Gene Rearrangement

“…Another possible cause is the inherent deficiency of using mitochondrial DNA without combination with nuclear markers for phylogenetic reconstructions, which has been proved in many other phylogenetic studies [ 55 , 56 , 57 ]. The basal position of Apachyidae as a sister group to other earwigs was supported in most trees of this study, which is consistent with the phylogenomic study of Wipfler et al (2020) [ 54 ] using nuclear single-copy genes. Apachyidae is also commonly considered a basal lineage in previous studies due to the presence of many primitive characters [ 4 , 19 , 54 , 58 ].…”

“…The basal position of Apachyidae as a sister group to other earwigs was supported in most trees of this study, which is consistent with the phylogenomic study of Wipfler et al (2020) [ 54 ] using nuclear single-copy genes. Apachyidae is also commonly considered a basal lineage in previous studies due to the presence of many primitive characters [ 4 , 19 , 54 , 58 ]. Despite the problematic placement of Anisolabididae, the close relationship between Pygidicranidae and Diplatyidae is supported in all trees, which also agrees with the result of Wipfler et al (2020) [ 54 ].…”

“…This result is confusing because Anisolabididae is apparently morphologically diverse from neither Haplodiplatyidae nor Diplatyidae. Although the phylogenetic position of Anisolabididae is also unresolved in previous morphological and molecular studies, it is often grouped with Spongiphoridae or Labiduridae [ 54 ]. This confusing clade might be caused by the probable misidentification of Euborellia arcanum Matzke & Kočárek, 2015, in Song et al (2016) [ 22 ].…”

Comparative mitogenomic analysis of two earwigs (Insecta, Dermaptera) and the preliminary phylogenetic implications

“…In the phylogenetic analyses, the monophyly of Forficulidae was supported with high values The basal phylogenetic position of Apachyidae was also recovered based on nuclear single-copy genes ( Wipfler et al 2020 ). However, the current relationship between the five earwig families is entirely incongruent with all previous phylogenetic studies using either morphological data, other types of molecular markers, or combined data ( Haas 1995 ; Guillet and Vancassel 2001 ; Haas and Kukalova-Peck 2001 ; Colgan et al 2003 ; Jarvis et al 2005 ; Kocarek et al 2013 ; Naegle et al 2016 ; Wipfler et al 2020 ). The preliminary phylogenetic analyses in current study included very few representatives from only five earwig families and thus insufficient for comparison with previous studies.…”

Penetration mechanics of elongated female and male genitalia of earwigs

“…This configuration of male and female genitalia is commonly known in Pygidicranidae 21 , 25 . Male genitalia with paired penis lobes are plausibly plesiomorphic conditions in Dermaptera 29 , 30 , although a plesiomorphic state of the orientation of the penises in repose remained unclear 30 .…”