It's time for Africa - hidden diversity of the Aphidius colemani species group (Hymenoptera, Braconidae, Aphidiinae) south of the Sahara.

Aphidius colemani is an important biological control agent, used in greenhouses and open fields against aphid pests. Despite this economical importance, A. colemani, along with A. transcaspicus and A. platensis, has gone through a complex taxonomical history. The three species have only recently gained status as separate species again, comprising the morphologically defined Aphidius colemani species group. Other than sporadic records probably as a consequence of escape from greenhouses, the A. colemani species group members prefer warmer regions and there are numerous records from South America, Southern Europe and Asia. Based on slide-mounted material collected in the period 1964-2001 in Africa, we describe five new species belonging to this group, and report A. colemani, A. transcaspicus and A. platensis from several African countries. This data opens questions about the origin of the group and presents potential for the diversification of biological control agents against aphid pests.

A new species of genus Monoctonus (Hymenoptera, Braconidae, Aphidiinae) from South Korea.

Background: The genus Monoctonus Haliday, 1833 is a small group which consists of 24 species worldwide. In South Korea, Chang and Youn (1983) recorded one species, M.similis Starý & Schlinger, 1967, but the evidence for identification of this species is doubtful and further confirmation is required (personal communication with Prof. Jong-Cheol Paik). New information: An additional Monoctonus species is recorded as new to science from South Korea. Descriptions and illustrations of the new species -Monoctonuskoreanus sp. nov. - are provided, together with its mitochondrial cytochrome c oxidase subunit I (COI) data and phylogenetic position. A key to the female of the two species present in Korea is provided.

Diversity of parasitoid wasps (Insecta, Hymenoptera) in oilseed rape fields in Serbia.

Background: Oilseed rape is an important crop grown worldwide and used for various purposes, including oil extraction and animal feed. In Europe, there are six major pest species and several other minor pests that can significantly affect oilseed rape production, requiring growers to effectively control them in order to ensure crop yield. The host-parasitoid complexes of these pests have been studied in detail and recorded mainly in western, central and northern Europe. As an abundant source of pollen and nectar, oilseed rape may also be attractive to other parasitoids that do not have direct trophic interactions with oilseed rape pest species. The aim of this study is to fill the knowledge gap regarding the wider parasitoid community in oilseed rape fields, particularly in southern Europe. New information: During the two-year study, a total of 3135 specimens of primary and secondary parasitoids were sampled, of which 2855 were found in oilseed rape fields and 280 in semi-natural habitats. We found 153 taxa, of which 119 were found in oilseed rape fields and 87 in semi-natural habitats. We identified 31 genera (33 species) as parasitoids of oilseed rape pests, 54 genera (97 species) parasitising non-pest species and 10 genera (23 species) as possible parasitoids of oilseed rape pests. This study shows that the parasitoid community in oilseed rape fields is very diverse and that includes parasitoids of both oilseed rape pest and non-pest species.

Four New Species of Pseudephedrus (Hymenoptera, Braconidae, Aphidiinae) from Chile with a Key to Species Identification.

The following work consists of the description of four new species of the genus Pseudephedrus Starý (Aphidiinae), endemic to South America, associated with endemic callaphidid aphid hosts. The descriptions of the new species are based on new samples from Chile and Argentina. The new species described here are as follows: Pseudephedrus staryi sp.n., which is morphologically very close to the already described P. chilensis Starý, with clear apomorphies; P. pubescens sp.n., which presents a setose scutellum, P. flava sp.n. and P. patagonicus sp.n. which have distinct, very elongated, and crenulated petioles representing synapomorphies and probably form separate phylogenetic lineages within Pseudephedrus. All hosts are aphids from the genus Neuquenaphis Blanchard, with varying degrees of diet specialization. From our field and laboratory observations, we hypothesize that, since attempts to sample parasitoids using sweep nets were much more successful than sampling from collected aphids, and since we found mummified aphids only on the ground among the fallen leaves under the trees, Neuquenaphis aphids fall to the ground showing a dropping behaviour as a defence against natural enemies after being stung by parasitoids. This makes rearing from live aphids very unsuccessful and could help explain why it has been difficult to collect and describe species. We supplement the distribution of Pseudephedrus from South America and present a key for the identification of all species based on their morphology.

Dyscrituluseuropaeus sp. nov. (Hymenoptera, Braconidae, Aphidiinae): description of a new aphid parasitoid species with an identification key for species of the genus.

The braconid genus Dyscritulus Hincks is a small member of the subfamily Aphidiinae, distributed in Europe and Central Asia. All its species are highly specialized parasitoids of aphids of the genera Drepanosiphum Koch and, probably, Periphyllus van der Hoeven which are mostly associated with maple and sycamore trees (genus Acer). Upon examination of specimens from the Naturalis Biodiversity Center, Leiden, we unexpectedly noted unusual variability in morphological characters compared to other known Dyscritulus species. Further inspection of other material previously identified as Dyscritulusplaniceps Marshall, 1896 revealed additional specimens with the same morphological variability. Here we describe a new species of the genus, Dyscrituluseuropaeussp. nov., associated with Drepanosiphum aphids on Acer.

Two new species of subtribe Monoctonina Mackauer from Europe (Hymenoptera, Braconidae, Aphidiinae).

Falciconus hispanicus sp. n. and Monoctonus montenegrinus sp. n. are described as new members of the subtribe Monoctonina from Spain and from high mountain habitats of Montenegro, respectively. The main diagnostic characters of the newly described species and their host plant-host aphid associations are discussed.

Do primary and secondary host plants affect aphid- parasitoid interactions in fruit orchards?

The aim of this study was to investigate how the primary (PHP) and secondary host plants (SHP) in the fruit orchards affect the interactions of aphids and their parasitoids in northwest Turkey during spring and summer 2020 and 2021. In total, 67 tritrophic aphid-parasitoid-host plant interactions, including new association records for Europe and Turkey, were obtained from 16 parasitoid species from the subfamily Aphidiinae (Hymenoptera: Braconidae) reared from 25 aphid species (Hemiptera: Aphididae) on 22 PHP and SHP in the fruit orchards. Also, we evaluated the effect of the PHP and SHP on the parasitoids, aphids and their interactions. We revealed that the species richness and the values of the biodiversity indices of the parasitoids and aphids were significantly higher on the SHP than the PHP. Similarly, the aphid-parasitoid interactions on the SHP showed greater diversity than the PHP. The results of this study clearly show that the interactions of parasitoids and aphids in the fruit orchards were more diverse on the SHP compared to the PHP.

Cereal Aphid Parasitoids in Europe (Hymenoptera: Braconidae: Aphidiinae): Taxonomy, Biodiversity, and Ecology.

Cereals are very common and widespread crops in Europe. Aphids are a diverse group of herbivorous pests on cereals and one of the most important limiting factors of cereal production. Here, we present an overview of knowledge about the taxonomy, biodiversity, and ecology of cereal aphid parasitoids in Europe, an important group of natural enemies contributing to cereal aphid control. We review the knowledge obtained from the integrative taxonomy of 26 cereal aphid primary parasitoid species, including two allochthonous species (Lysiphlebus testaceipes and Trioxys sunnysidensis) and two recently described species (Lipolexis labialis and Paralipsis brachycaudi). We further review 28 hyperparasitoid species belonging to three hymenopteran superfamilies and four families (Ceraphronoidea: Megaspillidae; Chalcidoidea: Pteromalidae, Encyrtidae; Cynipoidea: Figitidae). We also compile knowledge on the presence of secondary endosymbionts in cereal aphids, as these are expected to influence the community composition and biocontrol efficiency of cereal aphid parasitoids. To study aphid-parasitoid-hyperparasitoid food webs more effectively, we present two kinds of DNA-based approach: (i) diagnostic PCR (mainly multiplex PCR), and (ii) DNA sequence-based methods. Finally, we also review the effects of landscape complexity on the different trophic levels in the food webs of cereal aphids and their associated parasitoids, as well as the impacts of agricultural practices and environmental variation.

Resolving the Taxonomic Status of Potential Biocontrol Agents Belonging to the Neglected Genus Lipolexis Förster (Hymenoptera, Braconidae, Aphidiinae) with Descriptions of Six New Species.

Lipolexis is a small genus in the subfamily Aphidiinae represented by one species in Europe (Lipolexis gracilis Förster) and by four in Asia (Lipolexis wuyiensis Chen, L. oregmae Gahan, L. myzakkaiae Pramanik and Raychaudhuri and L. pseudoscutellaris Pramanik and Raychaudhuri). Although L. oregmae is employed in biological control programs against pest aphids, the last morphological study on the genus was completed over 50 years ago. This study employs an integrative approach (morphology and molecular analysis (COI barcode region)), to examine Lipolexis specimens that were sampled worldwide, including specimens from BOLD database. These results establish that two currently recognized species of Lipolexis (L. gracilis, L. oregmae) are actually a species complex and also reveal phylogenetic relationships within the genus. Six new species are described and a global key for the identification of Lipolexis species is provided.

Phylogeny of the Subtribe Monoctonina (Hymenoptera, Braconidae, Aphidiinae).

Members of the Monoctonina subtribe have long been neglected in applied studies of the subfamily Aphidiinae, due to their low economic importance, as they do not parasitize pests of cultivated plants. Consequently, data about this group are scarce, including its taxonomy and phylogeny. In the present study, we explore inter- and intraspecific genetic variation of Monoctonina species, including genera Monoctonus Haliday 1833, Monoctonia Starý 1962, Falciconus Mackauer 1959 and Harkeria Cameron 1900. We employ two molecular markers, the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) and the D2 region of the 28S nuclear gene (28S rDNA), to analyze genetic structuring and phylogeny of all available Monoctonina species, and combine them with morphological data for an integrative approach. We report one new species, and three potentially new species which can be formally described when further specimens are available. Analysis of phylogenetic relationships within the subtribe shows a basal position for the genera Falciconus and Monoctonia, and the close relatedness of Harkeria and Monoctonus.

Review of the world Monoctonina Mackauer 1961 (Hymenoptera, Braconidae, Aphidiinae): key for their identification and descriptions of five new species.

The subtribe Monoctonina has long been overlooked when it comes to morphological studies, probably due to the low economic importance of its members. Mainly distributed in high montane areas and forest ecosystems, species of Monoctonina are not often found in large populations and do not parasitize pests of cultivated plants. Our research uncovered five new species belonging to this subtribe (Monoctonus brachyradius sp. n., M. canadensis sp. n., M. inexpectatus sp. n., M. luteus sp. n., and M. parvipalpus sp. n.). We also redescribe species originally described over a century ago, and discuss the utility of certain morphological characters, as well as status of some species within Monoctonina.

Integrative taxonomy of root aphid parasitoids from the genus Paralipsis (Hymenoptera, Braconidae, Aphidiinae) with description of new species.

Species from the genus Paralipsis are obligatory endoparasitoids of root aphids in the Palaearctic. It is known that these species are broadly distributed, parasitizing various aphid hosts and showing great biological and ecological diversity. On the other hand, this group of endoparasitoids is understudied and was thought to be represented by a single species in Europe, viz., Paralipsisenervis (Nees). However, recent description of two new species indicated the possibility of cryptic speciation and recognition of additional Paralipsis species in Europe. In this research, Paralipsis specimens collected during the last 60 years from eight European countries, as well as one sample from Morocco, were subjected to molecular and morphological characterization. Newly designed genus-specific degenerative primers successfully targeted short overlapping fragments of COI of the mitochondrial DNA. Molecular analyses showed clear separation of four independent lineages, two of which are the known species P.enervis and P.tibiator, while two new species are described here, viz., P.brachycaudi Tomanovic & Starý, sp. n. and P.rugosa Tomanovic & Starý, sp. n. No clear specialization of the taxa to a strict root aphid host has been determined. The recognized mitochondrial lineages were distinct one from another, but with a substantial within-lineage divergence rate, clearly indicating the complexity of this group of parasitoids, on which further research is required in order to clarify the factors triggering their genetic differentiation. We reviewed literature data and new records of Paralipsisenervis aphid host associations and distributions. A key for the identification of all known Paralipsis species is provided and illustrated.

Hymenoptera Complex Associated with Myzus persicae and Hyalopterus spp. in Peach Orchards in Northeastern Spain and Prospects for Biological Control of Aphids.

Aphids are a serious pest for peach crops. They have traditionally been managed with insecticides, but there is increasing concern about the risk that insecticides pose to both humans and the environment. As a first step to use biological control in aphid management, we conducted a 3-year field survey in northeastern Spain to determine which parasitoids and hyperparasitoids were most prevalent on two aphids, Myzus persicae (Sulzer) and Hyalopterus spp. Koch, the most harmful to peach trees. We collected 11 parasitoid species from M. persicae, with Aphidius matricariae (Haliday) being the most abundant. Two parasitoid species were also collected from Hyalopterus spp., Aphidius transcaspicus Telenga and Praon volucre (Haliday). Hyperparasitoid species overlapped between these aphids but their relative abundances differed. We also discuss the possible impacts of hyperparasitoids on parasitoid populations. Our results suggest that it would be feasible to implement biocontrol methods for aphids in integrated pest management programmes in peach orchards. There are a number of primary parasitoid species associated with these aphids, and the nearby crops and wild vegetation in the vicinity and within the orchards may provide a suitable habitat for them. Additionally, some of them are commercially available and might be usable in augmentative releases.

Key for identification of the parasitoids (Hymenoptera: Braconidae: Aphidiinae) of aphids infesting alfalfa in Europe.

Although Aphidiinae parasitoids have been used as agents for biocontrol of alfalfa aphids for more than half a century and have been the subject of numerous ecological investigations, there is an evident lack of systematic studies on the parasitoids of aphids infesting alfalfa in Europe. Here we present an original and up-dated key for identification of both native and invasive Aphidiinae parasitoids attacking aphids that feed on alfalfa in Europe. In total, 20 species are keyed and illustrated with scanning electron micrographs and line drawings.

Species composition and seasonal dynamics of aphid parasitoids and hyperparasitoids in wheat fields in northern China.

Parasitoids are important natural enemies of aphids in wheat fields of northern China, and interest in them has increased in recent years. However, little is known regarding parasitoids of wheat aphids, which has hindered the study and understanding of aphid-parasitoid interactions. In the present study, three primary parasitoids and 15 hyperparasitoids were collected in wheat fields during a 2-year survey in northern China (2014, 2015) and a 2-year investigation at Langfang, Hebei Province (2015, 2016). Among them, Aphidius uzbekistanicus Luzhetski was found most frequently among the primary parasitoids, while Pachyneuron aphidis (Bouché) dominated the hyperparasitoid community. Investigation of the dynamics of wheat aphids and parasitoids revealed that the primary parasitoids appeared early in the growing period and that the hyperparasitoids appeared later. Analysis of the seasonal dynamics revealed that growth of the parasitoid population followed that of the aphid population and that the parasitism rates were highest in the late growing period.

Species composition and richness of aphid parasitoid wasps in cotton fields in northern China.

The cotton aphid, Aphis gossypii (Hemiptera: Aphididae), is a serious pest of cotton across the globe, particularly in the cotton agroecosystems of northern China. Parasitic wasps are deemed to be important natural enemies of A. gossypii, but limited information exists about their species composition, richness and seasonal dynamics in northern China. In this study, we combine sampling over a broad geographical area with intensive field trials over the course of three cropping seasons to describe parasitoid-hyperparasitoid communities in cotton crops. We delineate a speciose complex of primary parasitoids and hyperparasitoids associated with A. gossypii. Over 90% of the primary parasitoids were Binodoxys communis. Syrphophagus sp. and Pachyneuron aphidis made up most of the hyperparasitoids. Parasitism rates changed in a similar way following the fluctuation of the aphid population. Early in the growing period, there were more hyperparasitoids, while later, the primary parasitoids provided control of A. gossypii. The first systematic report of this cotton aphid parasitoid complex and their population dynamics in association with their hosts presented a comprehensive assessment of cotton parasitoid species and provided important information for the establishment and promotion of their biological control of cotton aphids.

An effective molecular approach for assessing cereal aphid-parasitoid-endosymbiont networks.

Molecular approaches are increasingly being used to analyse host-parasitoid food webs as they overcome several hurdles inherent to conventional approaches. However, such studies have focused primarily on the detection and identification of aphids and their aphidiid primary parasitoids, largely ignoring primary parasitoid-hyperparasitoid interactions or limiting these to a few common species within a small geographical area. Furthermore, the detection of bacterial secondary endosymbionts has not been considered in such assays despite the fact that endosymbionts may alter aphid-parasitoid interactions, as they can confer protection against parasitoids. Here we present a novel two-step multiplex PCR (MP-PCR) protocol to assess cereal aphid-primary parasitoid-hyperparasitoid-endosymbiont interactions. The first step of the assay allows detection of parasitoid DNA at a general level (24 primary and 16 hyperparasitoid species) as well as the species-specific detection of endosymbionts (3 species) and cereal aphids (3 species). The second step of the MP-PCR assay targets seven primary and six hyperparasitoid species that commonly occur in Central Europe. Additional parasitoid species not covered by the second-step of the assay can be identified via sequencing 16S rRNA amplicons generated in the first step of the assay. The approach presented here provides an efficient, highly sensitive, and cost-effective (~consumable costs of 1.3 € per sample) tool for assessing cereal aphid-parasitoid-endosymbiont interactions.

Evaluation of three molecular markers for identification of European primary parasitoids of cereal aphids and their hyperparasitoids.

Aphids are major pests of cereal crops and a suite of hymenopteran primary parasitoids play an important role in regulating their populations. However, hyperparasitoids may disrupt the biocontrol services provided by primary parasitoids. As such, understanding cereal aphid-primary parasitoid-hyperparasitoid interactions is vital for a reliable parasitoid-based control of cereal aphids. For this, the ability to identify the different primary and hyperparasitoid species is necessary. Unfortunately, this is often difficult due to a lack of morphologically diagnostic features. DNA sequence-based species identification of parasitoids can overcome these hurdles. However, comprehensive DNA sequence information is lacking for many of these groups, particularly for hyperparasitoids. Here we evaluate three genes [cytochrome c oxidase subunit I (COI), 16S ribosomal RNA (16S) and 18S ribosomal RNA (18S)] for their suitability to identify 24 species of primary parasitoids and 16 species of hyperparasitoids associated with European cereal aphids. To identify aphelinid primary parasitoid species and hyperparasitoids, we found 16S to be more suitable compared to COI sequences. In contrast, the Aphidiinae are best identified using COI due to better species-level resolution and a more comprehensive DNA sequence database compared to 16S. The 18S gene was better suited for group-specific identification of parasitoids, but did not provide resolution at the species level. Our results provide a DNA sequence database for cereal aphid primary parasitoids and their associated hyperparasitoids in Central Europe, which will allow further improvement of our understanding of cereal aphid-primary parasitoid-hyperparasitoid interactions in relation to aphid biological control.

Re-visiting the Aphidius urticae s. str. group: re-description of Aphidius rubi Starý and A. silvaticus Starý (Hymenoptera: Braconidae: Aphidiinae).

Here we tested Aphidius urticae s. str. host-associated lineages from Microlophium carnosum (Buckton), Amphorophora rubi (Kaltenbach), Macrosiphum funestum (Macchiati) and Aulacorthum vaccinii Hille Ris Lambers with the barcoding region of the mitochondrial cytochrome oxidase subunit I gene used to analyse population differences and elucidate phylogenetic relationships between the separated taxa. This molecular marker has been shown to be the most informative molecular marker in resolving species complexes in aphidiine parasitoids. Analyses of the mitochondrial sequences revealed the existence of three clearly separated mitochondrial lineages of A. urticae s. str. group associated with: i) Macrosiphum funestum and Aulacorthum vaccinii aphid hosts, ii) Microlophium carnosum and iii) Amphorophora rubi. This corresponds to the initial descriptions of A. rubi, A. silvaticus and A. urticae and their aphid host associations prior to synonymization of A. rubi and A. silvaticus with A. urticae. On the other hand, significant evolutionary distances ranging from 2.3 to 9.2% between the three mitochondrial lineages were not accompanied by clear morphological differences. Therefore, re-descriptions of A. rubi and A. silvaticus are presented, together with their morphological differentiation in a key, as well as their phylogenetic relationships and genetical differentiation.

The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage.

Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and host-use efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure.