The potential of the solitary parasitoid Microctonus brassicae for the biological control of the adult cabbage stem flea beetle, Psylliodes chrysocephala.

The cabbage stem flea beetle (CSFB), Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae), is a major pest of oilseed rape, Brassica napus L. (Brassicaceae), within the UK and continental Europe. Following the withdrawal of many broad-spectrum pesticides, most importantly neonicotinoids, and with increased incidence of pyrethroid resistance, few chemical control options remain, resulting in the need for alternative pest management strategies. We identified the parasitoid wasp Microctonus brassicae (Haeselbarth) (Hymenoptera: Braconidae) within CSFB collected from three independent sites in Norfolk, UK. Parasitism of adult CSFB was confirmed, and wasp oviposition behaviour was described. Moreover, we show that within captive colonies parasitism rates are sufficient to generate significant biological control of CSFB populations. A sequence of the M. brassicae mitochondrial cytochrome oxidase 1 (MT-CO1) gene was generated for rapid future identification. Moroccan specimens of Microctonus aethiopoides (Loan), possessing 90% sequence similarity, were the closest identified sequenced species. This study represents the first description published in English of this parasitoid of the adult cabbage stem flea beetle.

Endoparasitoid lifestyle promotes endogenization and domestication of dsDNA viruses.

The accidental endogenization of viral elements within eukaryotic genomes can occasionally provide significant evolutionary benefits, giving rise to their long-term retention, that is, to viral domestication. For instance, in some endoparasitoid wasps (whose immature stages develop inside their hosts), the membrane-fusion property of double-stranded DNA viruses have been repeatedly domesticated following ancestral endogenizations. The endogenized genes provide female wasps with a delivery tool to inject virulence factors that are essential to the developmental success of their offspring. Because all known cases of viral domestication involve endoparasitic wasps, we hypothesized that this lifestyle, relying on a close interaction between individuals, may have promoted the endogenization and domestication of viruses. By analyzing the composition of 124 Hymenoptera genomes, spread over the diversity of this clade and including free-living, ecto, and endoparasitoid species, we tested this hypothesis. Our analysis first revealed that double-stranded DNA viruses, in comparison with other viral genomic structures (ssDNA, dsRNA, ssRNA), are more often endogenized and domesticated (that is, retained by selection) than expected from their estimated abundance in insect viral communities. Second, our analysis indicates that the rate at which dsDNA viruses are endogenized is higher in endoparasitoids than in ectoparasitoids or free-living hymenopterans, which also translates into more frequent events of domestication. Hence, these results are consistent with the hypothesis that the endoparasitoid lifestyle has facilitated the endogenization of dsDNA viruses, in turn, increasing the opportunities of domestications that now play a central role in the biology of many endoparasitoid lineages.

Completing Linnaeus's inventory of the Swedish insect fauna: Only 5,000 species left?

Despite more than 250 years of taxonomic research, we still have only a vague idea about the true size and composition of the faunas and floras of the planet. Many biodiversity inventories provide limited insight because they focus on a small taxonomic subsample or a tiny geographic area. Here, we report on the size and composition of the Swedish insect fauna, thought to represent roughly half of the diversity of multicellular life in one of the largest European countries. Our results are based on more than a decade of data from the Swedish Taxonomy Initiative and its massive inventory of the country's insect fauna, the Swedish Malaise Trap Project The fauna is considered one of the best known in the world, but the initiative has nevertheless revealed a surprising amount of hidden diversity: more than 3,000 new species (301 new to science) have been documented so far. Here, we use three independent methods to analyze the true size and composition of the fauna at the family or subfamily level: (1) assessments by experts who have been working on the most poorly known groups in the fauna; (2) estimates based on the proportion of new species discovered in the Malaise trap inventory; and (3) extrapolations based on species abundance and incidence data from the inventory. For the last method, we develop a new estimator, the combined non-parametric estimator, which we show is less sensitive to poor coverage of the species pool than other popular estimators. The three methods converge on similar estimates of the size and composition of the fauna, suggesting that it comprises around 33,000 species. Of those, 8,600 (26%) were unknown at the start of the inventory and 5,000 (15%) still await discovery. We analyze the taxonomic and ecological composition of the estimated fauna, and show that most of the new species belong to Hymenoptera and Diptera groups that are decomposers or parasitoids. Thus, current knowledge of the Swedish insect fauna is strongly biased taxonomically and ecologically, and we show that similar but even stronger biases have distorted our understanding of the fauna in the past. We analyze latitudinal gradients in the size and composition of known European insect faunas and show that several of the patterns contradict the Swedish data, presumably due to similar knowledge biases. Addressing these biases is critical in understanding insect biomes and the ecosystem services they provide. Our results emphasize the need to broaden the taxonomic scope of current insect monitoring efforts, a task that is all the more urgent as recent studies indicate a possible worldwide decline in insect faunas.

Revision of the Oriental subgenus Patrisaspilota Fischer, 1995 (Hymenoptera: Braconidae: Alysiinae: Orthostigma Ratzeburg, 1844) with description of a new species from Papua New Guinea.

A revision of all Oriental species of subgenus Patrisaspilota Fischer, 1995 of the genus Orthostigma Ratzeburg, 1844 is provided and a new species from Papua New Guinea, Orthostigma (Patrisaspilota) enduwaense sp. nov., is described and illustrated. The species name Patrisaspilota memorandum Fischer, 1995 is synonymized with Orthostigma multicarinatum Tobias, 1990. A comprehensive key to the World Patrisaspilota species is presented and all known species are re-described and illustrated.

Multilocus phylogeny of the parasitic wasps in the tribe Euphorini (Hymenoptera: Braconidae) with revised generic classifications.

BACKGROUND: Parasitic wasps in the family Braconidae are important regulators of insect pests, particularly in forest and agroecosystems. Within Braconidae, wasps in the tribe Euphorini (Euphorinae) attack economically damaging plant bugs (Miridae) that are major pests of field and vegetable crops. However, the evolutionary relationships of this tribe have been historically problematic. Most generic concepts have been based on ambiguous morphological characters which often leads to misidentification, complicating their use in biological control. METHODS: Using a combination of three genes (COI, 28S, and CAD) and 80 taxa collected worldwide, we conducted Bayesian inference using MrBayes, and maximum likelihood analyses using RAxML and IQ-Tree on individual gene trees as well as the concatenated dataset. RESULTS: The monophyly of the tribe Euphorini and the two genera Peristenus and Leiophron were confirmed using maximum likelihood and Bayesian inference. The subgeneric classifications of Leiophron sensu lato were not supported, and the monotypic genus Mama was also not supported. DISCUSSION: Euphoriella, Euphoriana, Euphorus, and Mamasyn. n, have been synonymized under Leiophron. Mama mariaesyn. n was placed as a junior synonym of Leiophron reclinator. The generic concepts of Peristenus and Leiophron were refined to reflect the updated phylogeny. Further we discuss the need for revising Euphorini given the number of undescribed species within the tribe.

Review of the Palaearctic (and Oriental) Allurus (Braconidae, Euphorinae) based on material from Sweden.

BACKGROUND: The tribe Centistini includes three genera, Allurus, Centistes and Centistoides (Stigenberg et al. 2015). They are solitary endoparasitoids of adults and final instar larvae of beetles from the family Curculionidae (Jackson 1920, Aeschlimann 1980, Tobias 1986). NEW INFORMATION: In this paper we present a key, molecular data (standard DNA barcode, CO1) and images of the two species of Allurus occurring in the Western Palaearctic. A third Oriental species described from China (Taiwan) is also included in the key. Allurus is a Holarctic genus with three known species (A. choui, A. lituratus, A. muricatus). Our sequence data confirms that A. muricatus and A. lituratus are two distinct and separate species and this paper points out good and easy characters to separate them.