Capsella bursa-pastoris Is a Key Overwintering Plant for Aphids in the Mediterranean Region.

The reproduction of aphids depends to a great extent on their host plants, an integration that impacts on the successful expansion of overwintering populations. Therefore, a survey was conducted to evaluate the globally distributed Capsella bursa-pastoris as an overwintering host of economically important aphid species, their parasitoids and hyperparasitoids in the southern and western regions of Turkey from November to March in 2006 to 2013. During this survey, 395 samples of C. bursa-pastoris were collected with 25 aphid species recorded. Among aphids that feed on this host, Myzus persicae, Aphis gossypii, Rhopalosiphum padi, Aphis fabae, Aphis craccivora, Lipaphis erysimi, and Brevicoryne brassicae were the most frequently recorded. In total, 10,761 individual parasitoids were identified. Binodoxys angelicae, Aphidius colemani, Aphidius matricariae, Diaeretiella rapae, Ephedrus persicae, and Lysiphlebus confusus were the most abundant aphidiines that emerged from the aphids collected from C. bursa-pastoris. Alloxysta spp. (Hymenoptera: Cynipoidea), Chalcidoidea (unidentified at genus level), and Dendrocerus spp. (Hymenoptera: Ceraphronoidea) were identified as hyperparasitoids on the parasitoids. These findings indicate that C. bursa-pastoris is a key non-agricultural plant that significantly contributes to the overwintering of numerous aphids and their parasitoids, which should be given serious consideration when biological control strategies are designed.

Trioxys liui Chou & Chou, 1993 (Hymenoptera, Braconidae, Aphidiinae): an invasive aphid parasitoid attacking invasive Takecallis species (Hemiptera, Aphididae) in the Iberian Peninsula.

Biological invasion of aphids and other insects has been increased due to long distance commercial transportation of plant material. The bamboo-aphid-parasitoid association is strictly specific and even though it does not develop interactions with the local environment it should be listed as part of the fauna of southwestern Europe. On-going research regarding aphids and their aphidiine parasitoids in Spain has yielded a new association of Trioxys liui Chou & Chou, 1993 with an undescribed species of Takecallis aphids on bamboo, Phyllostachys spp. Here we present the first association of T. liui with aphids of the genus Takecallis that attack bamboos. Trioxys liui is known as a parasitoid of Cranaphis formosana (Takahashi, 1924) and Phyllaphoides bambusicola Takahashi, 1921 on bamboos in China and Russia. The accidental introduction of this parasitoid species to southwestern Europe has been probably realized through transportation of contaminated bamboo plant material. In the current study, a new host association is recorded for T. liui. Its potential to invade other bamboo-associated aphids and the significance of the tritrophic bamboo-aphid-parasitoid interactions in the new environments are also discussed.

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.

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.

Checklist of Aphidiinae (Hymenoptera: Braconidae) and Aphelinus (Hymenoptera: Aphelinidae) species from Belgium with respectively four and three new records.

Aphid parasitoids have good potential for crop protection. However, they have been poorly studied in Belgium, especially in terms of species diversity. Therefore, the aim of this work was to establish the first checklist for the country. To complete the list, aphid parasitoids were sampled in wheat and pea fields near Gembloux (Belgium), in 2013 and 2014. Among the identified species, Aphelinus asychis Walker, Aphelinus daucicola Kurdjumov, Aphelinus fusciscapus (Förster), Aphidius asteris Haliday, Aphidius eadyi Starý, Gonzalez & Hall, Praon barbatum Mackauer, and Trioxys auctus (Haliday) were recorded for the first time in Belgium. Thirty-two Aphidiinae and seven Aphelinus species were included in the checklist. It is hoped this study will stimulate further research, as species diversity is still low compared with neighbouring countries.

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.

Genetic and morphological variation in sexual and asexual parasitoids of the genus Lysiphlebus - an apparent link between wing shape and reproductive mode.

BACKGROUND: Morphological divergence often increases with phylogenetic distance, thus making morphology taxonomically informative. However, transitions to asexual reproduction may complicate this relationship because asexual lineages capture and freeze parts of the phenotypic variation of the sexual populations from which they derive. Parasitoid wasps belonging to the genus Lysiphlebus Foerster (Hymenoptera: Braconidae: Aphidiinae) are composed of over 20 species that exploit over a hundred species of aphid hosts, including many important agricultural pests. Within Lysiphlebus, two genetically and morphologically well-defined species groups are recognised: the "fabarum" and the "testaceipes" groups. Yet within each group, sexual as well as asexual lineages occur, and in L. fabarum different morphs of unknown origin and status have been recognised. In this study, we selected a broad sample of specimens from the genus Lysiphlebus to explore the relationship between genetic divergence, reproductive mode and morphological variation in wing size and shape (quantified by geometric morphometrics). RESULTS: The analyses of mitochondrial and nuclear gene sequences revealed a clear separation between the "testaceipes" and "fabarum" groups of Lysiphlebus, as well as three well-defined phylogenetic lineages within the "fabarum" species group and two lineages within the "testaceipes" group. Divergence in wing shape was concordant with the deep split between the "testaceipes" and "fabarum" species groups, but within groups no clear association between genetic divergence and wing shape variation was observed. On the other hand, we found significant and consistent differences in the shape of the wing between sexual and asexual lineages, even when they were closely related. CONCLUSIONS: Mapping wing shape data onto an independently derived molecular phylogeny of Lysiphlebus revealed an association between genetic and morphological divergence only for the deepest phylogenetic split. In more recently diverged taxa, much of the variation in wing shape was explained by differences between sexual and asexual lineages, suggesting a mechanistic link between wing shape and reproductive mode in these parasitoid wasps.

Revision of the world Monoctonia Starý, parasitoids of gall aphids: taxonomy, distribution, host range, and phylogeny (Hymenoptera, Braconidae: Aphidiinae).

The present paper represents a contribution to the knowledge of the taxonomy of Monoctonia Starý aphid parasitoids obtained using the barcoding region of the mitochondrial COI gene. We discuss the phylogenetic position of the genus within the subtribe Monoctonina, redescribe known species, and describe Monoctonia japonica sp. n. from Japan in the association Pemphigus matsumurai Monzen/Populus maximowiczii. A key for species identification is provided. Also, we review and discuss the host records, origin, and geographical distribution of Monoctonia species. It is hypothesized that the genus Monoctonia evolved in Paleogene forests of the temperate (and subtropical) belt, most probably in the European part of the Mediterranean region, which is also the center of origin of their host plants. 

Dispersal dynamics in food webs.

Studies of food webs suggest that limited nonrandom dispersal can play an important role in structuring food webs. It is not clear, however, whether density-dependent dispersal fits empirical patterns of food webs better than density-independent dispersal. Here, we study a spatially distributed food web, using a series of population-dispersal models that contrast density-independent and density-dependent dispersal in landscapes where sampled sites are either homogeneously or heterogeneously distributed. These models are fitted to empirical data, allowing us to infer mechanisms that are consistent with the data. Our results show that models with density-dependent dispersal fit the α, ß, and γ tritrophic richness observed in empirical data best. Our results also show that density-dependent dispersal leads to a critical distance threshold beyond which site similarity (i.e., ß tritrophic richness) starts to decrease much faster. Such a threshold can also be detected in the empirical data. In contrast, models with density-independent dispersal do not predict such a threshold. Moreover, preferential dispersal from more centrally located sites to peripheral sites does not provide a better fit to empirical data when compared with symmetric dispersal between sites. Our results suggest that nonrandom dispersal in heterogeneous landscapes is an important driver that shapes local and regional richness (i.e., α and γ tritrophic richness, respectively) as well as the distance-decay relationship (i.e., ß tritrophic richness) in food webs.

Parasitoids and hyperparasitoids (Hymenoptera) on aphids (Hemiptera) infesting citrus in east Mediterranean region of Turkey.

The aphids, aphid parasitoids, and hyperparasitoids found in citrus orchards, the parasitoids' and hyperparasitoids' seasonal abundance, and the plant-aphid-parasitoid relationships in Hatay, Osmaniye, Adana, and Mersin provinces of the east Mediterranean region of Turkey are presented in the present 2-yr study. Aphidius colemani Viereck, Binodoxys angelicae (Haliday), and Lysiphlebus confusus Tremblay and Eady (Hymenoptera: Braconidae: Aphidiinae) were encountered as the most common parasitoids among 10 identified aphidiine and aphelinid taxa on different citrus species. Hyperparasitoids belonging to the genera Alloxysta, Phaenoglyphis, Asaphes, Pachyneuron, Syrphophagus, and Dendrocerus are reported for the first time emerging from aphids feeding on citrus in Turkey. Among them, Asaphes spp., Pachyneuron spp., and Syrphophagus spp. were recorded as the most common ones. Citrus reticulata Blanco and Citrus limon (L.) Burm. fil. were recorded as main hosts for the aphid parasitoids and their hyperparasitoids.

Interference of field evidence, morphology, and DNA analyses of three related Lysiphlebus aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae).

This study provides evidence on integrating the morphological, field, and laboratory data, and application of the cytochrome oxidase subunit I (COI) barcoding gene to the three asexual or sexual Lysiphlebus spp., i.e., Lysiphlebus cardui (Marshall), Lysiphlebus confusus Tremblay and Eady and Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae). New aphid- invasive plant association, Aphis fabae Scopoli (Hemipreta: Aphididae) on Impatiens glandulifera Royle, has been used in the same model area in the Czech Republic under the same sampling and rearing method for several consecutive years and throughout the season. For molecular identification of these three species, we used DNA sequences of the barcoding region of the mitochondrial COI gene. Although our results confirmed ecological and morphological differences among L. cardui, L. confusus, and L. fabarum, genetic analysis on the basis of COI mitochondrial barcoding gene does not support species status of the mentioned Lysiphlebus taxa. The level of morphological differentiation in these Lysiphlebus Förster species is in accordance with the usual species variability within subfamily Aphidiinae. However, it should be examined how appearance of asexual lineages affects the morphological or genetical variability.

Lysiphlebus orientalis (Hymenoptera, Braconidae), a new invasive aphid parasitoid in Europe - evidence from molecular markers.

We report the occurrence of Lysiphlebus orientalis in Serbia, an aphid parasitoid from the Far East that is new to Europe and has the potential to become invasive. Our finding based on morphological characters is confirmed by analyses of mitochondrial cytochrome oxidase subunit I sequences. An increase in number and an expansion of the host range were observed during field studies over the past two years, and it is determined that the current host range encompasses nine aphid hosts on 12 different host plants, forming 13 tri-trophic associations. A host range determined for European populations of L. orientalis appears wider compared with that in its Far Eastern native habitats where Aphis glycines Mats. is the sole known host. Moreover, it overlaps considerably with the host ranges of European parasitoids that play an important role in the natural control of pest aphids.

Species of Adialytus Förster, 1862 (Hymenoptera, Braconidae, Aphidiinae) in Iran: taxonomic notes and tritrophic associations.

The species of Adialytus Förster in Iran are taxonomically studied and new data on distribution and host associations are presented. The existence of a species complex, in the case of Adialytus ambiguus (Haliday), and the morphological variability in commonly used taxonomic characters has been discussed. In total, four valid species belonging to the genus Adialytus including Adialytus ambiguus (Haliday), Adialytus salicaphis (Fitch), Adialytus thelaxis (Starý) and Adialytus veronicaecola (Starý) have been identified and recorded from Iran. Also, we recognized two additional phenotypes: "Adialytus arvicola" (Starý) and "Adialytus cf. ambiguus" (Haliday). These phenotypes and Adialytus veronicaecola are newly recorded from Iran in association with Sipha and Aphis species, respectively. An illustrated key for identification of the species and two variable phenotypes is presented.

Parasitoids (Hymenoptera: Braconidae: Aphidiinae) of northeastern Iran: aphidiine-aphid-plant associations, key and description of a new species.

Aphid parasitoids of the subfamily Aphidiinae (Hymenoptera: Braconidae) of northeastern Iran were studied in this paper. A total of 29 species are keyed and illustrated with line drawings. The aphidiines presented in this work have been reared from 42 aphid host taxa occurring on 49 plant taxa from a total of 33 sampling sites. Sixty-six aphidiine-aphid-plant associations are presented. Trioxys metacarpalis sp. nov. from Chaitaphis tenuicaudata Nevsky (Hemiptera: Aphididae) on Kochia scoparia, is described. The species diversity based on the comparative faunistic analysis is discussed.

Karyotype analysis of the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) reveals a large X chromosome with rRNA and histone gene families.

The Russsian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a worldwide pest of cereals. Despite its economic importance, little is known about its genome. Here we investigated physical genomic features in RWA by karyotype analysis using differential staining with AgNO(3), CMA(3), and DAPI, by chromosomal localization of ribosomal DNA (rDNA), H3 and H4 histone genes, and the "arthropod" telomeric sequence (TTAGG)(n) using fluorescence in situ hybridization (FISH), and by measuring the RWA genome size using flow cytometry. The female karyotype, 2n = 10, is composed of four autosome pairs and a pair of X chromosomes, whereas the male karyotype, 2n = 9, has a single X. The X chromosome is the largest element in the karyotype. All three molecular markers used, i.e., 18S rRNA and both H3 and H4 probes are co-localized at one end of the X chromosome. The FISH probes revealed that the AgNO(3)-positive bridge between two prometaphase X chromosomes of females, which is believed to be responsible for the elimination of one X chromosome in aphid oocytes determined to undergo male development, contains clusters of both histone genes, in addition to an rDNA cluster. Interestingly, RWA lacks the (TTAGG)(n) telomeric sequence in its genome, in contrast to several previously investigated aphid species. Additionally, we compared female and male genome sizes. The female genome size is 2C = 0.86 pg, whereas the male genome size is 2C = 0.70 pg. The difference between the DNA content in the two genders suggests that the RWA X chromosome occupies about 35% of the female haploid genome (1C = 0.43 pg), which makes it one of the largest sex chromosomes in the animal kingdom.

Global phylogenetics of Diuraphis noxia (Hemiptera: Aphididae), an invasive aphid species: evidence for multiple invasions into North America.

The Russian wheat aphid, Diruaphis noxia (Kudjumov) (Hemiptera: Aphididae), is globally one of the most devastating pests of bread wheat, Tritium aestivum L., durum wheat, Triticum turgidum L., and barley, Hordeum vulgare L. Several sources of D. noxia resistance have been incorporated in commercial wheat and barley genotypes, but up to eight virulent biotypes, defined based on their ability to damage different wheat and barley genotypes, now occur across the western United States since the first appearance of D. noxia in North America in 1986. Critical to the study of D. noxia and other invasive species is an understanding of the number and origin of invasions that have occurred, as well as the rate or potential of postinvasion adaptation and geographic range expansion. The goal of this study was to determine whether D. noxia biotypes are by-products of a single invasion or multiple invasions into North America. We used the genome-wide technique of amplified fragment length polymorphisms, in combination with 22 collections of D. noxia from around the world, to assess this question, as well as patterns of genetic divergence. We found multiple lines of evidence that there have been at least two D. noxia invasions of different origin into North America, each resulting in subsequent postinvasion diversification that has since yielded multiple biotypes.

Regional tritrophic relationship patterns of five aphid parasitoid species (Hymenoptera: Braconidae: Aphidiinae) in agroecosystem-dominated landscapes of southeastern Europe.

A regional survey of the complex tritrophic associations (parasitoid-aphid-plant) of aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) was carried out to determine and explore the patterns of those associations in various types of environments. Here, we present trophic relationship patterns of the five aphid parasitoid species in crop and noncrop habitats in southeastern Europe, and we contrast them in a regional (Mediterranean [MED] versus continental [CNT]) context. In total, 79 aphid host taxa were identified in this survey. Forty-two of these were recorded from noncrop plants only, 21 from crop plants only, and 18 were present on both types of plants. This means that approximately 74% of all the parasitoid-aphid trophic interactions that support the persistence of the five selected parasitoids are entirely (54%) or partially (20%) associated with noncrop plants. The correspondence of parasitoid-aphid combinations among habitat/region combinations is very high and specific. Our results suggest that Mediterranean and continental regions are clearly distinguished by a contrasting pattern of trophic interactions in crop habitats, whereas the noncrop habitats contribute in lesser degree to these differences. For the crop/noncrop breakdown, the number of nonspecific interactions was larger than expected in crop habitats, whereas in noncrop habitats the abundance of partially specific and specific interactions was larger. The analysis of variance for the regional and habitat distribution of mean aphid host number per parasitoid was highly significant. When both regions were analyzed separately, the parasitoid/crop design showed significant parasitoid effects as well as interactions, whereas the habitat effect was not significant for the Mediterranean region and highly so for the continental region. This highly complex pattern suggests that the mean number of parasitized aphid species is not distributed among parasitoids, regions, and habitats in a similar manner. Even with these complexities taken into account, the overall trend is that noncrop habitats support more parasitoid-aphid combinations and more so in the continental than in Mediterranean regions, although not always statistically significant. As mentioned, large number of noncrop aphid hosts, especially for Lysiphlebus fabarum (Marshall), Praon volucre (Haliday) and Aphidius colemani Viereck, can significantly enhance the population buildup for these important parasitoids around agroecosystems. These facts can be important in biological aphid pest control in the region. Although not easily quantified, the overall positive effects of larger parasitoid diversity in noncrop habitats are undoubtedly related to the distribution and structure of noncrop habitat patches in agroecosystems at a landscape scale.

Aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) and their associations related to biological control in Brazil

This study evaluated the parasitoid-aphid-plant associations in Brazil with the objective of developing a useful research database for further studies of aphid parasitoid ecology and aphid management. The original material was obtained from collections made in Paraná, Rio Grande do Sul, Minas Gerais, and São Paulo states. The published information on the Aphidiinae in Brazil is revised. The general features of the target parasitoid fauna of Central and South America is summarized and promising biological control programs of some aphid species in Brazil is discussed.

Este trabalho avaliou as interações parasitóides-pulgão-planta no Brasil, com o objetivo de desenvolver um banco útil de dados para estudos subseqüentes em ecologia de parasitóides de afídeos e manejo de pulgões. O material original foi obtido de coletas nos estados do Paraná, Rio Grande do Sul, Minas Gerais e São Paulo, sendo revisadas as informações sobre Aphidiinae publicadas no Brasil. Foram também sumarizadas as caracteristicas gerais da fauna de parasitóides das Américas Central e do Sul e discutidos os programas potenciais de controle biológico de algumas espécies de pulgões no Brasil.