Nicolas Borowiec

An integrative approach to species discrimination in the Eupelmus urozonus complex (Hymenoptera, Eupelmidae), with the description of 11 new species from the Western Palaearctic

The systematics of the European species of Eupelmus (Eupelmus) Dalman (Hymenoptera: Eupelmidae) belonging to the ‘urozonus‐complex’ is elucidated through combined molecular and morphological characterization. One mitochondrial gene fragment (Cytochrome oxidase I) and one nuclear protein‐coding gene fragment (Wingless) were sequenced and the results compared with those of a detailed morphological study of the specimens from an extensive sampling. Knowledge of the biodiversity of Eupelmus in the Western Palearctic Region is significantly improved through the separation and description of 11 new species: E. (Eupelmus) confusus Al khatib sp.n., E. gemellus Al khatib sp.n., E. janstai Delvare & Gibson sp.n., E. longicalvus Al khatib & Fusu sp.n., E. minozonus Delvare sp.n., E. opacus Delvare sp.n., E. pistaciae Al khatib sp.n., E. priotoni Delvare sp.n., E. purpuricollis Fusu & Al khatib sp.n., E. simizonus Al khatib sp.n. and E. tremulae Delvare sp.n. Illustrated keys to females and, when known, males of these new 11 species plus the other already described species considered to belong to the ‘urozonus‐complex’ (E. acinellus Askew, E. annulatus Nees, E. azureus Ratzeburg, E. cerris Förster, E. fulvipes Förster, E. kiefferi De Stefani, E. martellii Masi, E. stenozonus Askew, E. tibicinis Bouček and E. urozonus Dalman) are provided and all the species are described based on morphology. Eupelmus kiefferi is removed from synonymy under E. urozonus and E. azureus is recognized as the valid senior synonym of Pteromalus cordairii Ratzeburg, and Eupelmus spongipartus Förster, syn.n. The discrimination of the species included in this complex is particularly relevant because some are potential biological control agents and have been confused in the past.

Availability of eleven species names of Eupelmus (Hymenoptera, Eupelmidae) proposed in Al khatib et al. (2014)

Abstract This paper is an addendum for the availability of the names of 11 new species proposed in Al khatib et al. (2014).

Field Monitoring of Drosophila suzukii and Associated Communities in South Eastern France as a Pre-Requisite for Classical Biological Control

The spotted wing Drosophila, Drosophila suzukii (Ds), became a major economic pest for fruit production since its establishment in Europe and America. Among potential control methods, only classical biological control appears to be a mean of sustainably regulating Ds in both cultivated and natural habitats. In the frame of risk assessment, pre-release surveys were carried out in a restricted but highly heterogeneous area in the south-east of France using traps and deliberate field exposures of Ds and D. melanogaster larvae/pupae. Although Ds abundance varied according to sampling methods, it was found to be pervasive and to produce offspring and adults in most conditions (spatial and seasonal). Its main limits are some specific abiotic conditions (i.e., desiccation) as well as interspecific competition. Indeed, Ds mostly co-occurred with D. busckii and D. hydei, probably due to common phenology and/or ecological requirements. These two species thus deserve more attention for risk assessment. The main indigenous parasitoids collected belonged to two pupal species, Trichopria cf drosophilae and Pachycrepoideus vindemmiae, but their presence was observed late in the autumn and mainly in cultivated areas. Results are discussed in a comparison of the methodological approaches for monitoring Drosophilids and the benefits-risks assessment of classical biological control.

The parasitoid complex of D. suzukii and other fruit feeding Drosophila species in Asia

Drosophila suzukii is an invasive fly of East Asian origin that has become a serious fruit pest worldwide. Classical biological control through the introduction of parasitoids from Asia could help reduce populations of D. suzukii in invaded regions. Little is known about the native parasitoids of the fly in Asia. Therefore, surveys for larval parasitoids of D. suzukii were carried out in China and Japan between 2015 and 2017. Parasitoids of D. suzukii and other fruit-inhabiting drosophilids (D. pulchrella and D. subpulchrella) that are probably attacked by the same parasitoid complex were found in four Chinese provinces and four Japanese prefectures. Larval parasitoids were obtained at most sites where D. suzukii was found, with parasitism varying from 0.0 to 75.6%. At least eight parasitoid species were reared. The most abundant and frequent parasitoids were the Figitidae Ganaspis cf. brasiliensis and Leptopilina japonica, but another Leptopilina species and at least five Braconidae species belonging to the genera Areotetes, Asobara and Tanycarpa were obtained in low numbers. Due to its likely restricted host range, the most promising parasitoid for biological control is Ganaspis cf. brasiliensis. However, its exact specificity and taxonomic status require future research.

Early population dynamics in classical biological control: establishment of the exotic parasitoid Torymus sinensis and control of its target pest, the chestnut gall wasp Dryocosmus kuriphilus, in France

In response to the introduction and spread of the chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) in metropolitan France, including Corsica, the exotic parasitoid Torymus sinensis Kamijo (Hymenoptera: Torymidae) was deliberately introduced in more than 50 locations covering most of the areas of chestnut production. To test the impact of propagule pressure (i.e., the number and size of introductions) on establishment success and post‐release dynamics, the introductions were done according to three experimental modalities: (1) a single introduction of 100 females, (2) two sequential introductions of 50 females, or (3) a single introduction of 1 000 females. Post‐release surveys demonstrated a very high local establishment of T. sinensis, regardless of the introduction modality. Post‐introduction dynamics were found to follow a two‐phase process. First, early dynamics were characterized by an exponential growth of T. sinensis populations without a significant decrease in D. kuriphilus populations. Later, middle‐term dynamics indicated a global decrease in both D. kuriphilus and T. sinensis populations. Quite surprisingly, propagule pressure had a limited effect on post‐introduction dynamics, with a lasting demographic advantage for the largest introductions, but no influence of the number of introductions. Finally, site connectivity had a positive effect on T. sinensis population size, suggesting successful colonization and establishment at a wide spatial scale beyond the introduction sites. In addition, we observed that some T. sinensis exhibited a very short developmental time compared to the majority of the emerged individuals, which may be interpreted as a diversified bet hedging strategy against environmental stochasticity. These findings confirm the strong potential of T. sinensis for successful establishment and sustainable control of the chestnut gall wasp in Europe.

Life-history traits of Encarsia guadeloupae, a natural enemy of the invasive spiralling whitefly Aleurodicus dispersus

On south‐west Indian Ocean islands, many crops and ornamental plants are threatened by the spiralling whitefly Aleurodicus dispersus (Hemiptera: Aleyrodidae), which is a polyphagous pest that is native to the Caribbean region. Aleurodicus dispersus causes economic damage to various crops on all the islands in the south‐west Indian Ocean. The hymenopteran parasitoid Encarsia guadeloupae (Hymenoptera: Aphelinidae) is a natural enemy of A. dispersus on the Caribbean islands. In this study, we assessed the geographical distribution of the parasitoid in La Réunion, an island in the south‐west Indian Ocean where the parasitoid was first observed in 2004. We also investigated its main life‐history traits. Field surveys indicated that the parasitoid is widespread in most of the low‐lying areas of the island and exhibits high parasitism rates on A. dispersus populations. At 25°C, E. guadeloupae adults had a mean longevity of 33.6 days, and its pre‐imaginal development required 23 days. The lower temperature threshold and thermal constant were estimated to be 7.9°C and 132 degree‐days, respectively. Females of E. guadeloupae preferred to deposit eggs in early rather than in late instars of A. dispersus, and oviposition rates were highest in the second larval instar. Females of E. guadeloupae were able to oviposit in larvae of other species of whiteflies found in La Réunion (Bemisia tabaci and Dialeurolonga simplex), although subsequent development of the parasitoid was not monitored. Finally, we discuss the potential use of E. guadeloupae for the control of whitefly populations on islands in the south‐west Indian Ocean.