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.

New records of Orussus minutus Middlekauff, 1983 (Hymenoptera: Orussidae) represent a significant western range expansion

BACKGROUND

Orussus minutus is an uncommonly collected parasitoid sawfly known from the eastern United States.

NEW INFORMATION

We report specimens Orussus minutus Middlekauff, 1983, from Arkansas, Iowa, Minnesota, and Manitoba, which represent new state and province records and significantly expand the known range of the species west from previous records; provide collection information for unpublished specimens housed in the United States National Museum collection, which includes new state records for West Virginia and Michigan; and report two specimens housed in the Biological Museum at Lund University that represent new state records for Connecticut.

From Fossil Parasitoids to Vectors: Insects as Parasites and Hosts

Within Metazoa, it has been proposed that as many as two-thirds of all species are parasitic. This propensity towards parasitism is also reflected within insects, where several lineages independently evolved a parasitic lifestyle. Parasitic behaviour ranges from parasitic habits in the strict sense, but also includes parasitoid, phoretic or kleptoparasitic behaviour. Numerous insects are also the host for other parasitic insects or metazoans. Insects can also serve as vectors for numerous metazoan, protistan, bacterial and viral diseases. The fossil record can report this behaviour with direct (parasite associated with its host) or indirect evidence (insect with parasitic larva, isolated parasitic insect, pathological changes of host). The high abundance of parasitism in the fossil record of insects can reveal important aspects of parasitic lifestyles in various evolutionary lineages. For a comprehensive view on fossil parasitic insects, we discuss here different aspects, including phylogenetic systematics, functional morphology and a direct comparison of fossil and extant species.

Baltorussus total makeover: rejuvenation and sex change in an ancient parasitoid wasp lineage

The Orussidae is a small and rare but phylogenetically important family of parasitoid wasps. The fossil record of the family is also very poor. Baltorussus velteni was described from Baltic amber from an allegedly female specimen. This and another recently discovered specimen are examined with microCT scanning and standard microscopy. We reveal that both the holotype and the new specimen are actually males. Furthermore, the results of the microCT scanning allow us to integrate the fossils in a morphological data set assembled for extant Orussidae. Phylogenetic analyses consistently retrieve Baltorussus as a separate basal lineage within the crown group, whereas two Cretaceous fossils are placed as stem group orussids and a Dominican amber fossil in an extant genus. Based on the positions of the fossils, we estimate that the extant Orussidae radiated in the mid-Cretaceous (approx. 100 Ma ago). This is considerably younger than a previously suggested Early Jurassic date (180 Ma ago), which was primarily based on biogeographic evidence.