Phylogeny and DNA barcoding of inquiline oak gallwasps (Hymenoptera: Cynipidae) of the Western Palaearctic

Abstract

The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. We examine phylogenetic relationships within the Synergus complex of herbivorous 50 inquiline gallwasps associated with (Hymenoptera; Cynipidae; Synergini) associated with cynipid host galls on oak, a biologically diverse group whose genus-level morphological taxonomy has long been considered stable but whose species level taxonomy is problematic.We incorporate data for over 80% of recognised Western Palaearctic species in 5 morphology-based genera (Ceroptres, Saphonecrus, Synergus, Synophrus, Ufo), comprising 55 sequence for two mitochondrial two mitochondrial loci (coxI, cytb) and one nuclear locus (28S D2). In particular, we assess the evidence for monophyly of two long-established, morphology-defined sections within the genus Synergus that differ in a range of biological traits between-generation polymorphism and impact on the host gall inducer (lethal versus non-lethal). To aid analyses of ecological interactions within oak cynipid communities, we 60 also consider the utility of cytochrome oxidase I (coxI) DNA barcodes in the oak inquilines.In this assessment, we do not assume that species are delineated at a single threshold value of sequence divergence for a single gene, but examine concordance in the composition of molecular operational Taxonomic units (MOTUs) across a range of sequence divergences in each gene and across genes. We also assess the impact of sampling effort on MOTU stability. 65Phylogenetic reconstructions for all three loci support monophyly for Synergus and Synophrus, but reject monophyly for Saphonecrus and for the two sections within Synergus.The suites of traits associated with the two sections of the genus Synergus are thus homoplasious. All three loci also reject monophyly for three Synergus species (S. hayneanus, S. pallipes, S. umbraculus). Sequences for each locus identify robust MOTUs that are largely 70 concordant across loci for a range of cut-off values. Though many MOTU's correspond to recognised Linnean species, there is significant, multigene disagreement between groupings supported by morphology and sequence data, with both allocation of different morphospecies to the same MOTU and allocation of the same morphospecies to multiple MOTUs, regardless 3 of cutoff value. Our results imply that while DNA barcoding has considerable utility within 75 this group, morphology-based identification needs major revision at both genus and species levels. Further, lifehistory traits currently attributed to single morphospecies probably confound attributes of multiple lineages. Revealing patterns of character state evolution in Synergus requires collection of new host association and life history data explicitly linked to DNA barcode data for the specimens concerned. 80

Eastern Palearctic oak cynipid inquilines (Hymenoptera: Cynipidae: Synergini) and associated gallwasps (Hymenoptera: Cynipidae: Cynipini)

“…Probably all seven genera form together a distinct monophyletic lineage (Ronquist et al 2015) and Rhoophilus generally recovered as the sister taxon of all others (e.g. Ács et al 2010Ács et al , Ronquist et al 2015. The morphological taxonomy of Synergus complex has been studied in details (Mayr 1872;Wiebes-Rijks, 1979;Nieves-Aldrey & Pujade-Villar 1985PujadeVillar & Nieves-Aldrey 1990Liljeblad & Ronquist 1998;Liljebald et al 2008;PujadeVillar et al 2003, Melika 2006Bozsó et al 2015) and (i) supported the differentiation of these two lineages, and (ii) showed that five genera, Agastoroxenia, Saphonecrus, Synergus, Synophrus and Ufo morphologically differs from Ceroptres .…”

“…For example the presence of cryptic species, independently evolving lineages that are morphologically indistinguishable, had been demonstrated in many times (Ács et al 2010(Ács et al , Kaartinen et al 2010. Consequently it is becoming increasingly common to supplement morphological identifcation with molecular methods such as DNA barcoding (Hebert et al 2003).…”

“…Further fully overlapping sequences were downloaded from previous studies of gallwasp inquilines (Synergini) (Ács et al 2010;Pénzes et al 2009;Bozsó et al 2014;Kaartinen et al 2010, Bernardo et al 2013, Nylander et al 2004detailed below.). CoxI sequences were aligned without difficulty using Muscle 3.8.31 (Edgar et al 2004) using the default settings as no gaps were detected.…”

“…Saphonecrus closely resembles Synergus , Ács et al 2010, Schwéger et al 2015a. The two genera can be separated by a combination of characters: and maintained the genus, but also questioned its validity.…”

“…Within the tribe Synergini there is some contradiction between the morphology-based taxonomy and the molecular phylogeny when considering the classification above the species level, especially striking in the largest genera, Synergus and Saphonecrus (Melika 2006, Ács et al 2010). …”