Parasitoid Wasp Species Research Articles

Habitat or temporal isolation: Unraveling herbivore-parasitoid speciation patterns using double digest RADseq.

Ecological speciation is often observed in phytophagous insects and their parasitoids due to divergent selection caused by host‐associated or temporal differences. Most previous studies have utilized limited genetic markers or distantly related species to look for reproductive barriers of speciation. In our study, we focus on closely related species of Lygus bugs and two sister species of Peristenus parasitoid wasps. Using mitochondrial DNA COI and genomewide SNPs generated using ddRADseq, we tested for potential effects of host‐associated differentiation (HAD) or temporal isolation in this system. While three species of Lygus are clearly delineated with both COI and SNPs, no evidence of HAD or temporal differentiation was detected. Two Peristenus sister species were supported by both sets of markers and separated temporally, with P. mellipes emerging early in June and attacking the first generation of Lygus, while P. howardi emerging later in August and attacking the second generation of their hosts. This is one of the few studies to examine closely related hosts and parasitoids to examine drivers of diversification. Given the results of this study, the Lygus‐Peristenus system demonstrates temporal isolation as a potential barrier to reproductive isolation for parasitoids, which could indicate higher parasitoid diversity in regions of multivoltine hosts. This study also demonstrates that incorporating systematics improves studies of parasitoid speciation, particularly by obtaining accurate host records through rearing, carefully delimiting cryptic species and examining population‐level differences with genomic‐scale data among closely related taxa.

Previous Interspecific Courtship Impairs Female Receptivity to Conspecifics in the Parasitoid Wasp Nasonia longicornis But Not in N. vitripennis.

Interspecific sexual interactions are not uncommon in animals. In sympatry, females often face the risk of accidentally mating with a heterospecific male. Based on the actual risks imposed by the environment at a given time and place, females should be able to adjust their mate acceptance in order to avoid interspecific copulations as well as accidentally refusing to mate with a conspecific. We investigate the ability of females of the two parasitoid wasp species Nasonia vitripennis (Nv) and N. longicornis (Nl) to adjust their mate acceptance in response to previous unsuccessful courtship by heterospecific males. We show that Nl females are more reluctant to mate with a conspecific male when having been courted previously by a heterospecific male, but Nv females are not. We argue that this strategy is reasonable for Nl females but not for Nv females, which follow a different strategy to avoid the fitness costs imposed by heterospecific copulations.

Suppression of orb-web building behavior of the spider Metazygia laticeps (O. Pickard-Cambridge, 1889) (Araneae: Araneidae) by a new parasitoid wasp

Parasitoids may change host behavior in order to improve their survival during the pupal stage. This has been observed in some ichneumonid wasps (Polysphincta genus group), which are able to induce modifications in the movements of host spiders during web construction. These changes usually result in web patterns distinct from those of normal webs of spiders. In this study, we describe the behavioral change in the orb-weaver spider Metazygia laticeps (Araneidae), parasitized by a new species of parasitoid wasp, Polysphincta sinearaneasp. n. (Ichneumonidae), which has a high prevalence in M. laticeps populations. This parasitoid induces behavioral changes in M. laticeps that result in the complete suppression of the normal orb-web structure. The absence of the orb probably reduces accumulation of debris and interception of insects by the webs (factors that could result in the rupture of threads that hold the shelter of the web) during the period from cocoon construction to the emergence of the adult wasp. Also, the suppression of the normal orb-web structure implies that resources that would have been invested in the web will be available to the larva wasp.

Cotesia congregata Bracovirus Circles Encoding PTP and Ankyrin Genes Integrate into the DNA of Parasitized Manduca sexta Hemocytes.

Polydnaviruses (PDVs) are essential for the parasitism success of tens of thousands of species of parasitoid wasps. PDVs are present in wasp genomes as proviruses, which serve as the template for the production of double-stranded circular viral DNA carrying virulence genes that are injected into lepidopteran hosts. PDV circles do not contain genes coding for particle production, thereby impeding viral replication in caterpillar hosts during parasitism. Here, we investigated the fate of PDV circles of Cotesia congregata bracovirus during parasitism of the tobacco hornworm, Manduca sexta, by the wasp Cotesia congregata Sequences sharing similarities with host integration motifs (HIMs) of Microplitis demolitor bracovirus (MdBV) circles involved in integration into DNA could be identified in 12 CcBV circles, which encode PTP and VANK gene families involved in host immune disruption. A PCR approach performed on a subset of these circles indicated that they persisted in parasitized M. sexta hemocytes as linear forms, possibly integrated in host DNA. Furthermore, by using a primer extension capture method based on these HIMs and high-throughput sequencing, we could show that 8 out of 9 circles tested were integrated in M. sexta hemocyte genomic DNA and that integration had occurred specifically using the HIM, indicating that an HIM-mediated specific mechanism was involved in their integration. Investigation of BV circle insertion sites at the genome scale revealed that certain genomic regions appeared to be enriched in BV insertions, but no specific M. sexta target site could be identified.IMPORTANCE The identification of a specific and efficient integration mechanism shared by several bracovirus species opens the question of its role in braconid parasitoid wasp parasitism success. Indeed, results obtained here show massive integration of bracovirus DNA in somatic immune cells at each parasitism event of a caterpillar host. Given that bracoviruses do not replicate in infected cells, integration of viral sequences in host DNA might allow the production of PTP and VANK virulence proteins within newly dividing cells of caterpillar hosts that continue to develop during parasitism. Furthermore, this integration process could serve as a basis to understand how PDVs mediate the recently identified gene flux between parasitoid wasps and Lepidoptera and the frequency of these horizontal transfer events in nature.

Uninfested plants and honey enhance the attractiveness of a volatile blend to a parasitoid Cotesia vestalis

AbstractA blend of four volatile compounds, (Z)‐3‐hexene‐1‐yl acetate, α‐pinene, sabinene and n‐heptanal, emitted from cabbage plants infested by diamondback moth (DBM) larvae (hereafter called the attractant) attract females of Cotesia vestalis, a dominant parasitoid wasp species of DBM larvae. Here, we tested the effects of the presence of uninfested komatsuna (Brassica rapa var. perviridis L. cv. Rakuten) plants on the wasps’ response to the attractant in the choice chamber under laboratory conditions. Satiated female wasps were equally distributed between groups of 16 and four uninfested plants. However, the wasps preferred the group of 16 uninfested plants with the attractant to that of four uninfested plants with the attractant, indicating that the greater biomass of uninfested plants synergistically increased the attractiveness of the attractant. The effects of honey (a food of C. vestalis while rearing) on the wasps’ responses to the attractant were also tested using starved females. The wasps showed an equal distribution between honey with four uninfested plants and four uninfested plants. When both odour sources were coupled with the attractant, the wasps significantly preferred the former odour source, indicating a synergistic effect of honey on the attractiveness of the attractant. This effect, however, was observed when C. vestalis females had been reared with the tested honey but not when they had been reared with aqueous sucrose. In the experimental glasshouse, when comparing a group of infested plants coupled with uninfested plants, honey and the attractant to a group of infested plants, female wasps preferred the former. In addition, this preference was significantly greater than their preference for infested plants coupled with the attractant over infested plants. Thus, there was a synergistic effect of uninfested plants and honey on the attractiveness of the attractant–infested plant complex under glasshouse conditions.

Seven remarkable new fossil species of parasitoid wasps (Hymenoptera, Ichneumonidae) from the Eocene Messel Pit.

Parasitoid wasps of the family Ichneumonidae are one of the most diverse and species-rich groups of organisms with a worldwide distribution. We here describe seven new ichneumonid fossil species and two new genera from a remarkable insect fossil site, the Eocene Messel Pit in Germany (~47Ma). The unique fossil preservation allows us to place five out of the seven new species unequivocally in extant subfamilies and genera. For the first time, lobed claws which are a clear synapomorphy for the subfamily Pimplinae, are observed in a fossil, making the newly described Scambus fossilobus sp. nov. the oldest unequivocal representative of the group. We also describe a fossil of Labeninae (Trigonator macrocheirus gen. et sp. nov.), an ichneumonid subfamily that was until now believed to be an exclusively Gondwanan element. Furthermore, the newly described Rhyssella vera sp. nov., Xanthopimpla messelensis sp. nov., and X. praeclara sp. nov. provide evidence that these extant genera date back as far as the Early/Middle Eocene. In contrast to the clear placement of most of the newly described species, we were unable to place Polyhelictes bipolarus gen. et sp. nov. and Mesornatus markovici gen. et sp. nov. in an ichneumonid subfamily, mostly due to the high levels of homoplasy found in this group. These findings on the one hand demonstrate the need for a more rigorous approach in the taxonomic placement of fossil ichneumonids, and on the other hand provide more precise minimum ages for several ichneumonid genera and subfamilies.

Efficacy of using DNA barcoding to identify parasitoid wasps of the melon-cotton aphid (Aphis gossypii) in watermelon cropping system

Parasitoid wasps have received a great deal of attention in the biological control of melon-cotton aphid (Aphis gossypii Glover). The species of parasitoids are often difficult to identify because of their small body size and profound diversity. DNA barcoding offers scientists who are not expert taxonomists a powerful tool to render their field studies more accurate. Using DNA barcodes to identify aphid parasitoid wasps in specific cropping systems may provide valuable information for biological control. Here, we report the use of DNA barcoding to confirm the morphological identification of 14 species (belonging to 13 genera of 7 families) of parasitoid wasps from two-year field samples in a watermelon cropping system. We generated DNA sequences from the mitochondrial COI gene and the nuclear D2 region of 28S rDNA to assess the genetic variation within and between parasitoid species. Automatic Barcode Gap Discovery (ABGD) supported the presence of 14 genetically distinct groups in the dataset. Among the COI sequences, we found no overlap between the maximum K2P distance within species (0.49%) and minimum distance between species (6.85%). The 28S sequences also showed greater interspecific distance than intraspecific distance. DNA barcoding confirmed the morphological identification. However, inconsistency and ambiguity of taxonomic information available in the online databases has limited the successful use of DNA barcoding. Only five species matched those in the BOLD and GenBank. Four species did not match the entries in GenBank and five species showed ambiguous results in BOLD due to confusing nomenclature. We suggested that species identification based on DNA barcodes should be performed using both COI and other genes. Nonetheless, we demonstrate the potential of the DNA barcoding approach to confirm field identifications and to provide a foundation for studies aimed at improving the understanding of the biocontrol services provided by parasitoids in the melon ecosystem.

Comparative genomics of the miniature wasp and pest control agent Trichogramma pretiosum

BackgroundTrichogrammatids are minute parasitoid wasps that develop within other insect eggs. They are less than half a millimeter long, smaller than some protozoans. The Trichogrammatidae are one of the earliest branching families of Chalcidoidea: a diverse superfamily of approximately half a million species of parasitoid wasps, proposed to have evolved from a miniaturized ancestor. Trichogramma are frequently used in agriculture, released as biological control agents against major moth and butterfly pests. Additionally, Trichogramma are well known for their symbiotic bacteria that induce asexual reproduction in infected females. Knowledge of the genome sequence of Trichogramma is a major step towards further understanding its biology and potential applications in pest control.ResultsWe report the 195-Mb genome sequence of Trichogramma pretiosum and uncover signatures of miniaturization and adaptation in Trichogramma and related parasitoids. Comparative analyses reveal relatively rapid evolution of proteins involved in ribosome biogenesis and function, transcriptional regulation, and ploidy regulation. Chalcids also show loss or especially rapid evolution of 285 gene clusters conserved in other Hymenoptera, including many that are involved in signal transduction and embryonic development. Comparisons between sexual and asexual lineages of Trichogramma pretiosum reveal that there is no strong evidence for genome degradation (e.g., gene loss) in the asexual lineage, although it does contain a lower repeat content than the sexual lineage. Trichogramma shows particularly rapid genome evolution compared to other hymenopterans. We speculate these changes reflect adaptations to miniaturization, and to life as a specialized egg parasitoid.ConclusionsThe genomes of Trichogramma and related parasitoids are a valuable resource for future studies of these diverse and economically important insects, including explorations of parasitoid biology, symbiosis, asexuality, biological control, and the evolution of miniaturization. Understanding the molecular determinants of parasitism can also inform mass rearing of Trichogramma and other parasitoids for biological control.

Differences in the reliance on cuticular hydrocarbons as sexual signaling and species discrimination cues in parasitoid wasps

BackgroundCuticular hydrocarbons (CHC) have been documented to play crucial roles as species- and sex-specific cues in the chemical communication systems of a wide variety of insects. However, whether they are sufficient by themselves as the sole cue triggering sexual behavior as well as preference of con- over heterospecific mating partners is rarely assessed. We conducted behavioral assays in three representative species of parasitoid wasps (Hymenoptera: Pteromalidae) to determine their reliance on CHC as species-specific sexual signaling cues.ResultsWe found a surprising degree of either unspecific or insufficient sexual signaling when CHC are singled out as recognition cues. Most strikingly, the cosmopolitan species Nasonia vitripennis, expected to experience enhanced selection pressure to discriminate against other co-occurring parasitoids, did not discriminate against CHC of a partially sympatric species from another genus, Trichomalopsis sarcophagae. Focusing on the latter species, in turn, it became apparent that CHC are even insufficient as the sole cue triggering conspecific sexual behavior, hinting at the requirement of additional, synergistic sexual cues particularly important in this species. Finally, in the phylogenetically and chemically most divergent species Muscidifurax uniraptor, we intriguingly found both CHC-based sexual signaling as well as species discrimination behavior intact although this species is naturally parthenogenetic with sexual reproduction only occurring under laboratory conditions.ConclusionsOur findings implicate a discrepancy in the reliance on and specificity of CHC as sexual cues in our tested parasitioid wasps. CHC profiles were not sufficient for unambiguous discrimination and preference behavior, as demonstrated by clear cross-attraction between some of our tested wasp genera. Moreover, we could show that only in T. sarcophagae, additional behavioral cues need to be present for triggering natural mating behavior, hinting at an interesting shift in signaling hierarchy in this particular species. This demonstrates the importance of integrating multiple, potentially complementary signaling modalities in future studies for a better understanding of their individual contributions to natural sexual communication behavior.

Symbiotic polydnavirus and venom reveal parasitoid to its hyperparasitoids

Symbiotic relationships may provide organisms with key innovations that aid in the establishment of new niches. For example, during oviposition, some species of parasitoid wasps, whose larvae develop inside the bodies of other insects, inject polydnaviruses into their hosts. These symbiotic viruses disrupt host immune responses, allowing the parasitoid's progeny to survive. Here we show that symbiotic polydnaviruses also have a downside to the parasitoid's progeny by initiating a multitrophic chain of interactions that reveals the parasitoid larvae to their enemies. These enemies are hyperparasitoids that use the parasitoid progeny as host for their own offspring. We found that the virus and venom injected by the parasitoid during oviposition, but not the parasitoid progeny itself, affected hyperparasitoid attraction toward plant volatiles induced by feeding of parasitized caterpillars. We identified activity of virus-related genes in the caterpillar salivary gland. Moreover, the virus affected the activity of elicitors of salivary origin that induce plant responses to caterpillar feeding. The changes in caterpillar saliva were critical in inducing plant volatiles that are used by hyperparasitoids to locate parasitized caterpillars. Our results show that symbiotic organisms may be key drivers of multitrophic ecological interactions. We anticipate that this phenomenon is widespread in nature, because of the abundance of symbiotic microorganisms across trophic levels in ecological communities. Their role should be more prominently integrated in community ecology to understand organization of natural and managed ecosystems, as well as adaptations of individual organisms that are part of these communities.

Variation in the diversity and richness of parasitoid wasps based on sampling effort.

Parasitoid wasps are a mega-diverse, ecologically dominant, but poorly studied component of global biodiversity. In order to maximise the efficiency and reduce the cost of their collection, the application of optimal sampling techniques is necessary. Two sites in Auckland, New Zealand were sampled intensively to determine the relationship between sampling effort and observed species richness of parasitoid wasps from the family Ichneumonidae. Twenty traps were deployed at each site at three different times over the austral summer period, resulting in a total sampling effort of 840 Malaise-trap-days. Rarefaction techniques and non-parametric estimators were used to predict species richness and to evaluate the variation and completeness of sampling. Despite an intensive Malaise-trapping regime over the summer period, no asymptote of species richness was reached. At best, sampling captured two-thirds of parasitoid wasp species present. The estimated total number of species present depended on the month of sampling and the statistical estimator used. Consequently, the use of fewer traps would have caught only a small proportion of all species (one trap 7–21%; two traps 13–32%), and many traps contributed little to the overall number of individuals caught. However, variation in the catch of individual Malaise traps was not explained by seasonal turnover of species, vegetation or environmental conditions surrounding the trap, or distance of traps to one another. Overall the results demonstrate that even with an intense sampling effort the community is incompletely sampled. The use of only a few traps and/or for very short periods severely limits the estimates of richness because (i) fewer individuals are caught leading to a greater number of singletons; and (ii) the considerable variation of individual traps means some traps will contribute few or no individuals. Understanding how sampling effort affects the richness and diversity of parasitoid wasps is a useful foundation for future studies.

Record of six Pteromalid parasitoids from the soybean stem fly Melanagromyza sojae Zehntner with the description of a new species of Sphegigaster Spinola (Hymenoptera: Chalcidoidea) from Maharashtra, India

Field surveys were carried out in Pune area of Maharashtra state in India during June–September of 2014 and 2015 to determine the parasitoid species associated with stem fly Melanagromyza sojae Zehntner infesting soybean. Ten species of parasitoid wasps emerged from the collected materials and included six species of Pteromlaidae, and one species each from the families Eurytomidae, Figitidae (= Eucoilidae), Braconidae and Eulophidae. Six pteromalid parasitoids recorded were: Chlorocytus amaravathicus, Colotrechnus melghaticus, Halticoptera propinqua, Syntomopus carinatus, Syntomopus nigrus and Sphegigaster punensis sp. nov. Sureshan, Fand & Nikhil. Among pteromalids, S. punensis was dominant parasitoid during the mid-season, whereas C. amaravathicus, C. melghaticus, H. propinqua, S. carinatus and S. nigrus were present in low number towards the end of the season. Whilst S. carinatus constitute an already reported parasitoid species from M. sojae, this study reports for the first time M. sojae as a new host for the parasitoid species viz., C. amaravathicus, C. melghaticus and S. nigrus. For H. propinqua, this is the first record of the genus and species from M. sojae whereas, Sphegigaster punensis sp. nov. Sureshan, Fand & Nikhil is described for the first time as a new pteromalid species. Keys to the pteromlaid parastioids of M. sojae in general and species of Sphegigaster in particular are provided.http://zoobank.org/urn:lsid:zoobank.org:pub:A9C5E4C0-1251-458D-82CD-2741C4F43A93

In silico prediction of neuropeptides in Hymenoptera parasitoid wasps.

Parasitoid wasps of the order Hymenoptera, the most diverse groups of animals, are important natural enemies of arthropod hosts in natural ecosystems and can be used in biological control. To date, only one neuropeptidome of a parasitoid wasp, Nasonia vitripennis, has been identified. This study aimed to identify more neuropeptides of parasitoid wasps, by using a well-established workflow that was previously adopted for predicting insect neuropeptide sequences. Based on publicly accessible databases, totally 517 neuropeptide precursors from 24 parasitoid wasp species were identified; these included five neuropeptides (CNMamide, FMRFamide-like, ITG-like, ion transport peptide-like and orcokinin B) that were identified for the first time in parasitoid wasps, to our knowledge. Next, these neuropeptides from parasitoid wasps were compared with those from other insect species. Phylogenetic analysis suggested the divergence of AST-CCC within Hymenoptera. Further, the encoding patterns of CAPA/PK family genes were found to be different between Hymenoptera species and other insect species. Some neuropeptides that were not found in some parasitoid superfamilies (e.g., sulfakinin), or considerably divergent between different parasitoid superfamilies (e.g., sNPF) might be related to distinct physiological processes in the parasitoid life. Information of neuropeptide sequences in parasitoid wasps can be useful for better understanding the phylogenetic relationships of Hymenoptera and further elucidating the physiological functions of neuropeptide signaling systems in parasitoid wasps.

Bionomy of small spruce bud scale, Physokermes hemicryphus (Dalman) (Hemiptera: Coccidae) in Serbia

Small spruce bud scale, Physokermes hemicryphus (Dalman) (Hemiptera: Coccidae), is a Holarctic, oligophagous species developing on plants of the genera Picea and Abies (Pinaceae). It is a serious pest of Picea abies in Serbia, which causes drying and falling of needles, branches and even drying of entire plants. A study of the bionomy of Ph. hemicryphus was carried out at five locations in Serbia in 2016 and 2017. Ph. hemicryphus was found to develop one generation annually and to overwinter as second-instar larvae on spruce branches. Adults emerge at the beginning of April and oviposition takes place at the beginning of May. Larvae hatch in the second half of May; during summer they feed on spruce needles and moult into second-instar larvae in September. Scale populations are controlled by a number of natural enemies. Five species of parasitoid wasps were reared: Coccophagus lycimnia (Walker) (Hymenoptera: Aphelinidae), Metaphycus unicolor Hoffer, Microterys lunatus (Dalman), Pseudorhopus testaceus (Ratzeburg) (Hymenoptera: Encyrtidae) and Pachyneuron muscarum (L.) (Hymenoptera: Pteromalidae), as well as five predatory species: Anthribus nebulosus Forster (Coleoptera: Anthribidae), Exochomus quadripustulatus L., Scymnus abietis Paykull, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) and Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). The most efficient parasitoid of Ph. hemicryphus was P. testaceus, reducing scale populations up to 28.97%, while the most efficient predator was A. nebulosus with an efficacy of up to 51.72%.

Spatiotemporal variation in drivers of parasitoid metacommunity structure in continuous forest landscapes

AbstractAlthough landscape spatial structure is known to influence spatial patterns of biodiversity, its effect on insect communities at higher trophic levels such as parasitoids remains poorly understood. This is particularly true in continuously distributed forests in which it can be difficult to identify clear boundaries among habitat patches. Using the metacommunity framework, we evaluate the relative importance of forest landscape structure, non‐environmental spatial structure, and host outbreak status to spatial and within‐season temporal variation in parasitoid communities. We used variation partitioning and metacommunity structure analyses to identify (1) the drivers of the metacommunity structure of parasitoids associated with the spruce budworm (Choristoneura fumiferana), and (2) how their relative influence varies through a season. We used a multi‐scale perspective to summarize landscape heterogeneity in regions of increasing size around the community sampling locations. Spruce budworm larvae and pupae were sampled during three periods during the summer 2014 in 18 locations within continuous forest landscapes in Quebec, Canada. Thirty‐two parasitoid wasp and fly species were recorded, 16 of which were found at more than one location. We found that the mechanisms shaping metacommunity structure changed over the course of a single season and that community structure varied among sites. At early and late periods in the season, we found that non‐environmental structure, forest structure, and likely inter‐specific competition were the main mechanisms influencing spatial variation in community structure. These results suggest a competition–dispersal trade‐off. In contrast, at the middle period of the season, environmental filtering by forest structure and stochastic events were found to influence community structure. This period corresponds to the transition between early and late parasitoid communities. Our findings on the role of environmental filtering and forest structure support the idea that forest manipulations have the potential to influence parasitoid populations and hence spruce budworm outbreak dynamics as hypothesized by the “enemies hypothesis.” Moreover, our study highlights the value of considering a multi‐scale approach and temporal variability of species interactions when characterizing the multiple processes shaping spatial metacommunity structure, particularly in continuous environments.

Variation in the species richness of parasitoid wasps (Ichneumonidae: Pimplinae and Rhyssinae) across sites on different continents

Abstract The old idea that parasitoid wasps (Ichneumonidae) show an inverse latitudinal diversity gradient has recently been challenged, but how ichneumonid species richness varies across the globe is still not well understood. We carried out field inventories in 21 sites on three continents to clarify this question, focusing on the subfamilies Pimplinae and Rhyssinae. Our total sampling effort was 628 Malaise trap months and the total catch exceeded 65 000 individuals. Our main focus was in two intensively inventoried areas in Amazonia, together yielding 257 Malaise trap months and 26 390 ichneumonid individuals. To expand the scope and assess global species diversity patterns of the Pimplinae and Rhyssinae, we compiled published species lists from a total of 97 study localities around the world. The highest observed species richness in any locality, 105 species, was found in one of our field sites in Peruvian Amazonia. None of the other localities reported more than 70 species, even the ones with a sampling effort comparable to ours. Despite the local thoroughness of our field inventories in Amazonia, data analyses indicated that a substantial proportion of the parasitoid wasp species occurring in each site remained unobserved. The highest local species richness values were reported from the tropics. Nevertheless parasitoid wasps are still too sparsely sampled to draw solid conclusions about whether or not their species richness follows a particular latitudinal trend, and if so, where their richness peaks.

A Horizontally Transferred Autonomous Helitron Became a Full Polydnavirus Segment in Cotesia vestalis.

Bracoviruses associate symbiotically with thousands of parasitoid wasp species in the family Braconidae, working as virulence gene vectors, and allowing the development of wasp larvae within hosts. These viruses are composed of multiple DNA circles that are packaged into infective particles, and injected together with wasp’s eggs during parasitization. One of the viral segments of Cotesia vestalis bracovirus contains a gene that has been previously described as a helicase of unknown origin. Here, we demonstrate that this gene is a Rep/Helicase from an intact Helitron transposable element that covers the viral segment almost entirely. We also provide evidence that this element underwent at least two horizontal transfers, which appear to have occurred consecutively: first from a Drosophila host ancestor to the genome of the parasitoid wasp C. vestalis and its bracovirus, and then from C. vestalis to a lepidopteran host (Bombyx mori). Our results reinforce the idea of parasitoid wasps as frequent agents of horizontal transfers in eukaryotes. Additionally, this Helitron-bracovirus segment is the first example of a transposable element that effectively became a whole viral circle.

Ethanol confers differential protection against generalist and specialist parasitoids of Drosophila melanogaster.

As parasites coevolve with their hosts, they can evolve counter-defenses that render host immune responses ineffective. These counter-defenses are more likely to evolve in specialist parasites than generalist parasites; the latter face variable selection pressures between the different hosts they infect. Natural populations of the fruit fly Drosophila melanogaster are commonly threatened by endoparasitoid wasps in the genus Leptopilina, including the specialist L. boulardi and the generalist L. heterotoma, and both wasp species can incapacitate the cellular immune response of D. melanogaster larvae. Given that ethanol tolerance is high in D. melanogaster and stronger in the specialist wasp than the generalist, we tested whether fly larvae could use ethanol as an anti-parasite defense and whether its effectiveness would differ against the two wasp species. We found that fly larvae benefited from eating ethanol-containing food during exposure to L. heterotoma; we observed a two-fold decrease in parasitization intensity and a 24-fold increase in fly survival to adulthood. Although host ethanol consumption did not affect L. boulardi parasitization rates or intensities, it led to a modest increase in fly survival. Thus, ethanol conferred stronger protection against the generalist wasp than the specialist. We tested whether fly larvae can self-medicate by seeking ethanol-containing food after being attacked by wasps, but found no support for this hypothesis. We also allowed female flies to choose between control and ethanol-containing oviposition sites in the presence vs. absence of wasps and generally found significant preferences for ethanol regardless of wasp presence. Overall, our results suggest that D. melanogaster larvae obtain protection from certain parasitoid wasp species through their mothers’ innate oviposition preferences for ethanol-containing food sources.

Brachymeria mochica, a new Neotropical species of Chalcididae (Hymenoptera: Chalcidoidea) discovered on the archaeological site of Huacas de Moche, Peru with a review of related species

Two parasitoid wasp species of the Brachymeria minuta species group are studied. The specimens were collected in Peru at the archaeological site of Huacas de Moche, the former capital of the Mochica culture between 400–600 A.D. Brachymeria mochica Delvare sp. nov. (Chalcididae) is described and illustrated while B. podagrica (Fabricius, 1787) is reviewed with an update of the nomenclature and a summary of knowledge regarding its hosts and biology. The morphology and biology of both species are newly defined and characterized. Brachymeria brevicornis (Klug, 1834) stat. rev., previously synonymized with B. minuta (Linnaeus, 1767), is re-established as a valid species and a lectotype is designated. The following names are synonymised with B. podagrica: Chalcis ferox Kieffer, 1905 and its variety C. ferox coxalis Kieffer, 1905, Chalcis spilopus Cameron, 1905, Chalcis capensis Cameron, 1905, Chalcis transvaalensis Cameron, 1911, Chalcis neglecta Masi, 1916, Chalcis sodalis Masi, 1917, Brachymeria Fonscolombei var. gananensis Masi, 1938, Chalcis vulcani Schmitz, 1946, and Brachymeria fonscolombei f. neglecta Masi, 1951 new synonymies. Brachymeria amenocles (Walker, 1846) stat. rev. is re-established as a valid species with Chalcis varipes Walker, 1871 and Brachymeria Beccarii Masi, 1929 as junior synonyms syn. rev. Lectotypes are designated for the above names except for C. sodalis and C. vulcani.

The chemical basis of mate recognition in two parasitoid wasp species of the genus Nasonia

AbstractTo recognize one's mate is essential for all sexually reproducing animals. In insects, mate recognition is often based on chemical cues such as hydrocarbons which are distributed over the insect's cuticle. In the parasitoid wasp genus Nasonia (Hymenoptera: Pteromalidae), interspecific mating possibly occurs in microsympatry between Nasonia vitripennis Walker and Nasonia giraulti Darling despite post‐zygotic isolation mechanisms preventing hybridization. Males of N. vitripennis are known to equally court con‐ and heterospecific females, which they recognize by means of cuticular hydrocarbons. A recent study surprisingly showed that this might not be the case in N. giraulti, leaving open how males of this species achieve the recognition of mating partners. In this study, we investigated chemical mate recognition in N. giraulti in more detail and compared observed behaviors with behaviors of N. vitripennis by conducting experiments with both species concurrently and under the same experimental conditions. We disentangled the role of female‐derived non‐polar cuticular lipids – i.e., cuticular hydrocarbons – and more polar cuticular lipids in the ability of males to recognize con‐ and heterospecific females. In addition, we tested whether females of the two species discriminate similarly between con‐ and heterospecific males. We demonstrate that, in contrast to N. vitripennis, males of N. giraulti prefer live conspecific females over heterospecific ones. Furthermore, in contrast to N. vitripennis, mate recognition in N. giraulti males is not based on cuticular hydrocarbons, but rather involves other chemical messengers, presumably more polar cuticular lipids. In both species, discrimination against heterospecific males decreases with female age.