Phylogenomics and biogeography of sawflies and woodwasps (Hymenoptera, Symphyta).

Phylogenomic approaches have recently helped elucidate various insect relationships, but large-scale comprehensive analyses on relationships within sawflies and woodwasps are still lacking. Here, we infer the relationships and long-term biogeographic history of these hymenopteran groups using a large dataset of 354 UCE loci collected from 385 species that represent all major lineages. Early Hymenoptera started diversifying during the Early Triassic âˆ¼249 Ma and spread all over the ancient supercontinent Pangaea. We recovered Xyeloidea as a monophyletic sister group to other Hymenoptera and Pamphilioidea as sister to Unicalcarida. Within the diverse family Tenthredinidae, our taxonomically and geographically expanded taxon sampling highlights the non-monophyly of several traditionally defined subfamilies. In addition, the recent removal of Athalia and related genera from the Tenthredinidae into the separate family Athaliidae is supported. The deep historical biogeography of the group is characterised by independent dispersals and re-colonisations between the northern (Laurasia) and southern (Gondwana) palaeocontinents. The breakup of these landmasses led to ancient vicariance in several Gondwanan lineages, while interchange across the Northern Hemisphere has continued until the Recent. The little-studied African sawfly fauna is likewise a diverse mixture of groups with varying routes of colonization. Our results reveal interesting parallels in the evolution and biogeography of early hymenopterans and other ancient insect groups.

The First Ptilodactyla Illiger, 1807 (Coleoptera: Dryopoidea: Ptilodactylidae) Described from Eocene Baltic Amber.

The beetle family Ptilodactylidae contains more than 500 extant species; however, its fossil record is scarce and remains understudied. In this study, we describe a new species of Ptilodactylidae, Ptilodactyla eocenica Kundrata, Bukejs and Blank, sp. nov., based on a relatively well-preserved specimen from Baltic amber. We use X-ray microcomputed tomography to reconstruct its morphology since some of the principal diagnostic characters have been obscured by opaque bubbles. It is the third ptilodactylid species described from Baltic amber, and the first one belonging to the subfamily Ptilodactylinae. Additionally, we summarize the classification, diversity, and distribution of both extinct and extant Ptilodactylidae.

First microsatellite markers for the pine catkin sawfly Xyela concava (Hymenoptera, Xyelidae) and their application in phylogeography and population genetics.

Microsatellites are widely used as powerful markers in population genetics because of their ability to access recent genetic variation and to resolve subtle population genetic structures. However, their development, especially for non-model organisms with no available genome-wide sequence data has been difficult and time-consuming. Here, a commercial high-throughput sequencing approach (HTS) was used for the very first identification of microsatellite motifs in the genome of Xyela concava and the design of primer pairs flanking those motifs. Sixteen of those primer pairs were selected and implemented successfully to answer questions on the phylogeography and population genetics of X. concava. The markers were characterized in three geographically distinct populations of X. concava and tested for cross-species amplification in two additional Xyela and one Pleroneura species (Xyelidae). All markers showed substantial polymorphism as well as revealing subtle genetic structures among the three genotyped populations. We also analyzed a fragment of the nuclear gene region of sodium/potassium-transporting ATPase subunit alpha (NaK) and a partial mitochondrial gene region coding for cytochrome oxidase subunit I (COI) to demonstrate different genetic resolutions and sex-biased patterns of these markers, and their potential for combined use in future studies on the phylogeography and population genetics of X. concava. Although a limited number of populations was analyzed, we nevertheless obtained new insights on the latter two topics. The microsatellites revealed a generally high gene flow between the populations, but also suggested a deep historical segregation into two genetic lineages. This deep genetic segregation was confirmed by NaK. While the high gene flow was unexpected, because of assumed restricted dispersal ability of X. concava and the discontinuous distribution of the host trees between the populations, the segregation of two lineages is comprehensible and could be explained by different refuge areas of the hosts during glacial times. The COI results showed a discordant strong genetic structure between all populations, which might be explained by the smaller effective population size of the mitochondrial genome. However, given the frequent evidence of a similar nature in recent studies on sawflies, we also consider and discuss mitochondrial introgression on population level as an alternative explanation.

Fauna Europaea: Hymenoptera - Symphyta & Ichneumonoidea.

Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all extant European terrestrial and freshwater animals, their geographical distribution at the level of countries and major islands (west of the Urals and excluding the Caucasus region), and some additional information. The Fauna Europaea project comprises about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. Fauna Europaea represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. For the Hymenoptera, taxonomic data from one grade (Symphyta) and one Superfamily (Ichneumonoidea), including 15 families and 10,717 species, are included. Ichneumonoidea is the largest superfamily of Hymenoptera and consisting of two extant families, Ichneumonidae and Braconidae. The costal cell of the fore wing is absent, the fore wing has at least two closed cells, the constriction between the mesosoma (thorax + first abdominal segment or propodeum) and the metasoma (remainder of abdomen) is distinct and the parasitoid larvae usually spin a silken cocoon. Also, the metasoma is ventrally partly desclerotized in the vast majority of ichneumonoids.

Bird droppings on chestnut leaves or sawfly larvae: DNA barcodes verify the occurrence of the archaic Megaxyela togashii (Hymenoptera, Xyelidae) in Hokkaido, Japan.

We made a molecular phylogenetic analysis using mitochondrial cytochrome oxidase subunit 1 (COI) gene sequences for ten unidentified Megaxyela larvae from Hokkaido, Honshu and Shikoku, Japan, and 15 identified adults of four Megaxyela, one Macroxyela and three Xyela species. It revealed that all larvae belonged to M. togashii Shinohara, 1992, which showed rather large intraspecific genetic variability even among the individuals from the same population. This is the first distribution record of M. togashii from Hokkaido. Megaxyela togashii is a univoltine species with a very short larval feeding period, only nine days in one rearing experiment from egg to larval maturation. The larva is a solitary, external leaf-feeder on Juglans ailanthifolia, resting curled around the central leaf vein at the apex of a leaflet, and may resemble the excrement of birds. The prepupa overwinters in an earthen cell whose wall is made only of soil, neither parchment-like nor containing fiber. The mature larva is described and several life traits are discussed.

Identification of sawflies and horntails (Hymenoptera, 'Symphyta') through DNA barcodes: successes and caveats.

The 'Symphyta' is a paraphyletic assemblage at the base of the order Hymenoptera, comprising 14 families and about 8750 species. All have phytophagous larvae, except for the Orussidae, which are parasitoids. This study presents and evaluates the results of DNA barcoding of approximately 5360 specimens of 'Symphyta', mainly adults, and 4362 sequences covering 1037 species were deemed of suitable quality for inclusion in the analysis. All extant families are represented, except for the Anaxyelidae. The majority of species and specimens are from Europe, but approximately 38% of the species and 13% of the specimens are of non-European origin. The utility of barcoding for species identification and taxonomy of 'Symphyta' is discussed on the basis of examples from each of the included families. A significant level of cryptic species diversity was apparent in many groups. Other attractive applications include the identification of immature stages without the need to rear them, community analyses based on metabarcoding of bulk samples and association of the sexes of adults.

Trachelus stipa (Hymenoptera: Cephidae), a new stem sawfly from Central Anatolia associated with feather grass (Stipa holosericea, Poaceae).

Trachelus stipa is described from Central Anatolia, Turkey. It is morphologically close to T. flavicornis and T. troglodyta regarding the structure of the preapical sterna of the male. It is unique among Trachelus species regarding the shape of the claw of the posterior leg, the size of the denticles of the ovipositor and the short valvula 3 of the ovipositor sheath in the female, and the distally notched hypopygium in the male. The genetic distance found in two mitochondrial (COI and cyt b) and one nuclear (EF-1α) gene regions support the recognition of this species and its placement within Trachelus, although the shape of the ovipositor sheath disagrees with this concept. Stipa holosericea, the host of T. stipa according to field observations, represents the first record of a feather grass as the host of a sawfly species.

Invertebrate and avian predators as drivers of chemical defensive strategies in tenthredinid sawflies.

BACKGROUND: Many insects are chemically defended against predatory vertebrates and invertebrates. Nevertheless, our understanding of the evolution and diversity of insect defenses remains limited, since most studies have focused on visual signaling of defenses against birds, thereby implicitly underestimating the impact of insectivorous insects. In the larvae of sawflies in the family Tenthredinidae (Hymenoptera), which feed on various plants and show diverse lifestyles, two distinct defensive strategies are found: easy bleeding of deterrent hemolymph, and emission of volatiles by ventral glands. Here, we used phylogenetic information to identify phylogenetic correlations among various ecological and defensive traits in order to estimate the relative importance of avian versus invertebrate predation. RESULTS: The mapping of 12 ecological and defensive traits on phylogenetic trees inferred from DNA sequences reveals the discrete distribution of easy bleeding that occurs, among others, in the genus Athalia and the tribe Phymatocerini. By contrast, occurrence of ventral glands is restricted to the monophyletic subfamily Nematinae, which are never easy bleeders. Both strategies are especially effective towards insectivorous insects such as ants, while only Nematinae species are frequently brightly colored and truly gregarious. Among ten tests of phylogenetic correlation between traits, only a few are significant. None of these involves morphological traits enhancing visual signals, but easy bleeding is associated with the absence of defensive body movements and with toxins occurring in the host plant. Easy bleeding functions through a combination of attributes, which is corroborated by an independent contrasts test indicating a statistically significant negative correlation between species-level integument mechanical resistance and hemolymph feeding deterrence against ants. CONCLUSIONS: Our analyses evidence a repeated occurrence of easy bleeding, and no phylogenetic correlation including specific visual signals is significant. We conclude that the evolution of chemically-based defenses in tenthredinids may have been driven by invertebrate as much as by avian predation. The clear-cut visual signaling often encountered in the Nematinae would be linked to differential trends of habitat use by prey and predators. Further studies on (prey) insect groups should include visual signals and other traits, as well as several groups of natural enemies, to better interpret their relative significance and to refine our understanding of insect chemical defenses.

The Eurasian species of Xyela (Hymenoptera, Xyelidae): taxonomy, host plants and distribution.

The 28 Eurasian species of Xyela Dalman, 1819 are revised based on material of ca 7,500 imagines including about 10 % reared specimens. Larvae of Eurasian Xyela usually are monophagous and feed inside the staminate cones of pines (Pinus spp., Pinaceae). Based on the reared material, on identification by barcoding and on additional collection observations, the larval host associations for the Xyela species are summarized and additional biological observations are noted. An illustrated key to the species and distribution maps are presented. Eight species are described as new: X. altenhoferi Blank, sp. nov. (Croatia), X. heldreichii Blank, sp. nov. (Albania, Greece), X. koraiensis Blank & Shinohara, sp. nov. (Russia, South Korea), X. peuce Blank, sp. nov. (Bulgaria), X. pumilae Blank & Shinohara, sp. nov. (Japan), X. rasnitsyni Blank & Shinohara, sp. nov. (China, Russia, South Korea), X. sibiricae Blank, sp. nov. (Mongolia, Russia), and X. uncinatae Blank, sp. nov. (Andorra, France, Spain, Switzerland). For the other species redescriptions are given. A lectotype is designated for X. longula Dalman, 1819, and neotypes are designated for X. graeca J.P.E.F. Stein, 1876 and Pinicola julii Brébisson, 1818. The following new synonymies are proposed: X. lii Xiao, 1988, syn. nov. of X. sinicola Maa, 1947; X. nigroabscondita Haris & Gyurkovics, 2011, syn. nov. of X. lugdunensis (Berland, 1943); and X. suwonae Ryu & Lee, 1992, syn. nov. of X. ussuriensis Rasnitsyn, 1965.

When hymenopteran males reinvented diploidy.

In most plants and animals, a consistent relationship exists between the DNA content of a cell and its metabolic activity. The male-haploid sex determination of Hymenoptera and other arthropods may therefore impose a particular selective pressure upon males, which must evolve adaptations to cope with a genomic DNA reduced by half compared with that of females. Here, we show that a nuclear DNA content similar to that of females is restored in muscles of males in all hymenopteran lineages tested except the most basal one (Xyelidae). This doubling of DNA content in males does not occur in other haplodiploid insects, such as thrips (Thysanoptera) and whiteflies (Sternorrhyncha). These results indicate that this adaptation probably occurred early in hymenopteran history, possibly because males acquired strong flying and dispersal abilities.