Adult Wasps Research Articles

Phylogenomic insights and geographic distribution of the New World genus Amphibolips Reinhard (Hymenoptera: Cynipidae, Cynipini) using ultraconserved elements

AbstractIn recent years, new wasp species and genera of Cynipidae have been described, and their species delimitation and evolutionary relationships have been supported using molecular markers. However, few studies have included comprehensive and extensive sampling of specimens across the complete distribution of a single genus. In this study, we analysed the phylogenetic relationships of the genus Amphibolips throughout its range using ultraconserved elements (UCEs). We collected 520 adult wasps from 401 sites in various geographic locations, predominantly in Mexico, and used 78 wasps for UCE analysis. Our results demonstrate that Amphibolips forms a monophyletic clade. Amphibolips can be further subdivided into four genetically well‐differentiated clades. Each clade had morphological traits that could be collectively characterised. Species delimitation using molecular sequencing highlights the taxonomic complexity involved in separating and assigning species using exclusively morphological criteria. This approach offers an opportunity to refine current morphological taxonomic criteria or propose new criteria to establish more accurate classifications. The rich diversity of host species and geographic regions in Mexico represents a biodiversity hotspot for Amphibolips. The number of undescribed species remains high. This study facilitates the determination of appropriate boundaries for putative new Amphibolips species.

Nesting and mating behaviours, and the development time of three solitary digger wasps of the genus Ammophila (Hymenoptera: Sphecidae)

Abstract Nesting and mating behaviours and the development time of Ammophila clavus (Fabricius), Ammophila globifrontalis Q.Li & Ch.Yang, and Ammophila laevigata F.Smith from Vietnam are presented. All three dig their nests in the ground. The nest entrance is round. The nest burrow is nearly vertical and ends with an elliptical cell. The cell contains 1–2 caterpillars. The egg is usually glued on the third abdominal segment of prey. The three wasps temporarily close their nest burrows just below the entrance when provisioning, but permanently close them above or at the nest cells when full provision is complete. As the last stage of nest construction, the nest entrance is camouflaged with small sticks and several pebbles. Males of both Ammophila clavus and Ammophila laevigata patrol nesting areas, pursue females searching for their nest sites, pounce upon them, and mate with them on the ground. The development time from egg to the emergence of adult wasps is more than one month, males always emerging before females. The nesting behaviour of the three Ammophila species is compared and discussed.

First report of Trypoxylon clavicerum (Crabronidae: Hymenoptera) from the Indian subcontinent: its nesting behaviour and prey preference

Abstract A study was conducted to document the nesting behaviour and prey composition of a crabronid wasp, Trypoxylon sp. The wasp was molecularly characterised as T. clavicerum (NCBI Accession No. OQ913679.1). Nest acceptance rate was significantly higher in the reeds of Ipomea carnea (79.20%) and bamboo (84.80%). The mean number of brood cells (4.40 ± 0.89 cells/nest) and vestibular cells (1.06 cells/nest) built by the wasp was significantly higher in the reeds of I. carnea. Brood parasitisation by the nest parasite Amobia sp. was significantly higher in nests built by the wasp in paper straws (58.57%) compared to the nests built in the reeds of bamboo (23.33%). The mean durations of the egg, larval and pupal stages of T. clavicerum were 2.60 ± 0.55, 6.01 ± 0.71 and 4.80 ± 0.84 days. The number of nests recovered was observed to be the highest during the months of August (3.66 ± 1.53 nests), September (5.00 ± 4.36 nests), October (8.67 ± 2.89 nests) and November (6.00 ± 2.10 nests). The major species of spider from the occupied nests belonged to two families, viz. Salticidae (81%) and Oxyopidae (19%). During the nesting period the adult wasp provisioned a greater number of spiderlings (3.25 to 3.60 spiderlings/cell) than adult spiders (1.20 to 1.60 adult spiders/cell) to her brood. The time taken to complete a single nest provisioned with adult spiders and spiderlings (13.20 ± 6.83 hr/single nest) was significantly less than for the nests provisioned with adult spiders (46.80 ± 14.80 hr/single nest) only. This study is the first ever report of nesting behaviour and prey composition of the spider-hunting wasp T. clavicerum from India.

Assaying Nociception Behaviors in Drosophila Larvae During Parasitoid Wasp Attacks.

Nociception in fruit fly (Drosophila melanogaster) larvae is characterized by a stereotyped escape behavior. When a larva encounters a noxious (potentially harmful) stimulus, it responds by curving its body into a c-shape and rolling in a corkscrew-like manner around its long-body axis. This rolling behavior may serve to quickly remove the larva from the source of the noxious stimulus, and is particularly adaptive to escape from a common natural predator of fruit fly larvae: parasitoid wasps (Leptopilina boulardi). L. boulardi completes its life cycle by using fruit fly larvae as hosts for its offspring. Female wasps sting fly larvae with an ovipositor and lay an egg within the larva. The wasp offspring hatches inside the fly larva, consumes the fly tissues during pupation, and eventually emerges from the pupal case as an adult wasp. Fruit fly larvae respond to oviposition attacks by rolling, which causes the long flexible ovipositor to be wound around the larval body like a spool. This dislodges the wasp and allows the larva to attempt to escape by crawling. Rolling behavior is triggered by the activation of sensory neurons (nociceptors) whose function can inform our understanding of the mechanisms of nociception. In this protocol, we describe a simple behavioral assay to test and measure nociceptive responses in Drosophila larvae during oviposition attacks by female parasitoid wasps. First, we discuss parasitoid wasp husbandry and culturing methods in the laboratory. We then describe how to perform the wasp nociception assay on third-instar fruit fly larvae.

Supplementary sugars enhance the production efficiency and parasitism performance of the egg parasitoid Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae).

Trichogramma spp. wasps are egg parasitoids with a long history of mass rearing for augmentation biocontrol programs in field crop and orchard landscapes. Supplementary nutrition can improve the longevity, fecundity, and biocontrol efficacy of parasitoids. To improve the production efficiency and parasitism performance of Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae), the present study screened and examined the potential supplementary nutrients for this biological control agent. Dietary supplementation with a 10% sucrose solution significantly increased wasp longevity and parasitism potential of T. dendrolimi on host eggs, but provision of pollen did not provide additional benefits. Laboratory and greenhouse cage tests demonstrated that wasp access to soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) honeydew, comprised primarily of melezitose and trehalose, improved T. dendrolimi longevity and parasitism. In conclusion, provision of a 10% sucrose solution to adult wasps will enhance the mass-rearing efficiency of T. dendrolimi; furthermore, field release of T. dendrolimi by plant vectors bearing honeydew-producing aphids holds promise for improving the biocontrol efficacy of T. dendrolimi.

Contrasting responses of drosophila pupal parasitoids to heat waves in the larval and adult stages

Abstract The life history of parasitoids is divided into a parasitic immature stage living in or on a host invertebrate and a free‐living adult stage. We still have little consensus on how larvae and adult parasitoids differ in their responses to environmental heat waves. We tested the performance of two cosmopolitan drosophila pupal parasitoids, Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae) and Trichopria drosophilae (Hymenoptera: Diapriidae), when exposed to 35 and 40°C heat waves in the larval and adult stage, respectively. Additionally, we tested if heat hardening in the larval stage influenced the thermal tolerance of adult parasitoids. P. vindemiae had a higher tolerance to heat waves than T. drosophilae in both the larval and adult stages. We did not find significantly increased thermal tolerance of adult wasps that experienced heat hardening during the larval stage. A 35°C heat wave had no effect on P. vindemiae. Larval T. drosophilae that experienced a 35°C heat wave had longer development times, but individuals that survived showed no significant decrease in longevity and fecundity compared with those without warming experience. By contrast, adult T. drosophilae suffered less mortality from the 35°C heat wave, but individuals that survived had significantly reduced longevity and fecundity. A 40°C heat wave resulted in higher mortality in the larval stage than in the adult stage for both parasitoid species. Our study clearly revealed the contrasting responses to heat waves in the larval and adult stages of two parasitoids and highlighted the importance of ontogenetic differences in thermal tolerance in predicting parasitoid distributions and population dynamics.

Assessment of non-target toxicity of insecticides on Ganaspis brasiliensis (Ihering) in laboratory and field conditions.

G1 strain Ganaspis brasiliensis (Ihering) has been recently released in both Europe and America as a biological control agent of the spotted wing drosophila, Drosophila suzukii (Matsumura). In initial phases of classical biological control programs, it becomes imperative to evaluate the susceptibility of parasitoids to insecticides, to identify the best alternatives to adopt in an integrated pest management and organic perspective. In this study, we evaluated lethal and sublethal effects of topical application of five different insecticides classes: neonicotinoids, diamides, pyrethroids, organophosphates and spinosyns. Additionally, we tested residual toxicity in field trials in vineyards and sweet cherry orchards. Adult wasps' susceptibility to different insecticides' classes were consistent between laboratory and field. Spinosad exhibited the highest toxicity, with a median lethal concentration (LC50) of 0.00372 of the maximum field dose, and the highest knock-down effect in field trials, causing 92.5 ± 5% of mortality at T0. λ-cyhalothrin showed sublethal effects on both male and female insects' longevity when applied at LC30. In field trials, deltamethrin showed the highest persistence, causing significant parasitoid mortality up to 14 days after treatment. Conversely, cyantraniliprole was the least toxic active ingredient according to both topical and residual bioassays, even though its residues caused mortality up to 7 days after the treatment in the field. Our results indicate that spinosad and λ-cyhalothrin are highly toxic to G. brasiliensis, making them incompatible with classical biological control programs. Cyantraniliprole exhibited lower toxicity, and may be considered a selective pesticide for the integrated management of D. suzukii. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A new species of Diolcogaster (Hymenoptera: Braconidae) from Brazil of potential use in the biological control of the pest Hypercompe brasiliensis (Stoll) (Lepidoptera: Erebidae).

Species of Diolcogaster parasitize Lepidoptera pests of commercial plants. The diversity of this genus is high, but few species of Diolcogaster have been described. The description of a new Diolcogaster species provides information for the biological control using this insect. This study presents the description and key notes on the biology of a new Diolcogaster parasitoid wasp. This species was reared from a caterpillar of Hypercompe brasiliensis collected after feeding on a Gloxinia perennis plant important to floriculture. Two complementary identification analyzes were performed on Diolcogaster adult bodies. The first was the analyses of its external morphology and the second its molecular analysis (mitochondrial DNA). The morphological analysis defined the insect as a new species of Diolcogaster, named Diolcogaster joanesi sp. nov. A maximum-likelihood (ML) analysis partially confirmed the morphological analysis, placing D. joanesi within a cluster including a previously identified species (Diolcogaster choi) and seven other morphospecies. The proximity of D. joanesi to D. choi is discussed and an updated key for all New World species of the xanthaspis group is provided. Twenty-eight adult wasps were obtained (22 females and six males) out of 50 cocoons which larvae emerged from the caterpillar host. The findings contribute to the broader understanding of Diolcogaster in the Neotropics and its potential for the biological control of lepidopteran defoliators.

Shaping the Microbial Landscape: Parasitoid-Driven Modifications of Bactrocera dorsalis Microbiota

Koinobiont endoparasitoids regulate the physiology of their hosts through altering host immuno-metabolic responses, processes which function in tandem to shape the composition of the microbiota of these hosts. Here, we employed 16S rRNA and ITS amplicon sequencing to investigate whether parasitization by the parasitoid wasps, Diachasmimorpha longicaudata (Ashmaed) (Hymenoptera: Braconidae) and Psyttalia cosyrae (Wilkinson) (Hymenoptera: Braconidae), induces gut dysbiosis and differentially alter the gut microbial (bacteria and fungi) communities of an important horticultural pest, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). We further investigated the composition of bacterial communities of adult D. longicaudata and P. cosyrae to ascertain whether the adult parasitoids and parasitized host larvae share microbial taxa through transmission. We demonstrated that parasitism by D. longicaudata induced significant gut perturbations, resulting in the colonization and increased relative abundance of pathogenic gut bacteria. Some pathogenic bacteria like Stenotrophomonas and Morganella were detected in both the guts of D. longicaudata-parasitized B. dorsalis larvae and adult D. longicaudata wasps, suggesting a horizontal transfer of microbes from the parasitoid to the host. The bacterial community of P. cosyrae adult wasps was dominated by Arsenophonus nasoniae, whereas that of D. longicaudata adults was dominated by Paucibater spp. and Pseudomonas spp. Parasitization by either parasitoid wasp was associated with an overall reduction in fungal diversity and evenness. These findings indicate that unlike P. cosyrae which is avirulent to B. dorsalis, parasitization by D. longicaudata induces shifts in the gut bacteriome of B. dorsalis larvae to a pathobiont-dominated community. This mechanism possibly enhances its virulence against the pest, further supporting its candidacy as an effective biocontrol agent of this frugivorous tephritid fruit fly pest.

Catalogue of Sceliphron destillatorium (Illager, 1807) (Hymenoptera, Sphecidae) specimens deposited in the State Museum of Natural History NASU, Lviv, Ukraine

Representatives of the genus Sceliphron Klug, 1801 are found in almost all biogeographical regions of the world (Yuan, 2022). At present, 35 species of this genus have been known (Pulawski, 2020). Of these, six species have been recorded from the territory of Ukraine as follows: three invasive species: Sceliphron caementarium (Drury, 1773); Sceliphron curvatum (Smith, 1870) and Sceliphron deforme (F. Smith, 1856) (Kletʹonkin, 2023); and three native species: Sceliphron destillatorium (Illiger, 1807); Sceliphron madraspatanum (Fabricius, 1781) and Sceliphron spirifex (Linnaeus, 1758) (Tymkiv et al., 2015). The most common is Sceliphron destillatorium (Illiger, 1807), which occurs throughout the territory of Ukraine. Representatives of the genus Sceliphron Klug, 1801 belong to two subgenera: Sceliphron and Hensenia. Although species of both subgenera take care of their offspring and feed the larvae with spiders, their nests differ in shape and number of mud cells. Wasps of the subgenus Hensenia build a certain number of single-celled mud nests in shape of jugs. Instead, wasps of the subgenus Sceliphron build cells that joint into large mud nest. S. destillatorium is the South–Palaearctic species. Its range covers the Mediterranean region (southern and south-eastern Europe, northern Africa and south-western and southern Asia) (Wisniowski et al., 2013). S. destillatorium is a solitary wasp. It belongs to the family Sphecidae (Insecta: Hymenoptera) of the subgenus Sceliphron (Gülmez1 et al, 2017). S. destillatorium female builds a nests of the moist soil material, which she collects and transports herself. The nest consists of tubular cells placed side by side, the number of which varies (Chatenoud et al., 2012). After building the first cell, the female hunts spiders to feed her offspring (Pytel-Huta, 2023; Yuan, 2022). Female S. destillatorium brings the paralysed spider into the cell, lays an egg and continues to hunt. Each cell stores a certain number of spiders. The number depends on the size of the victims and the sex of the future generation. Once the cells have been built, the female S. destillatorium covers them with an additional layer of soil (Polidori, 2005). In the wild, females build their nests in shady, sheltered places (rock ledges, empty tree trunks, etc.). However, at present, they are increasingly nesting in people's houses (usually under roofs, attics, etc.) (Yuan, 2022). Adult wasps feed on angiosperm nectar. The collection of the State Museum of Natural History, National Academy of Sciences in Lviv contains 14 specimens of this species collected in the western part of Ukraine and one specimen collected in the central part. A few samples (4) of this species were collected in 1922, 1923 and 1926, collector – J. Noskiewicz. The date and place of collection of the remaining specimens are unknown. All data have been entered into the web resource Data Centre “Biodiversity of Ukraine” http://dc.smnh.org/.

Transcriptomic analysis of cold stress-response in Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae)

Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) is a solitary ectoparasitoid that parasitizes several stored product beetles. Implementing an effective cold storage program can extend the shelf life of parasitoids for large scale applications in biological control. To explore the low temperature adaptation mechanisms of A. calandrae, the survival, longevity, parasitism rate, fecundity, and transcriptome of cold-treated A. calandrae adults were investigated. Storing A. calandrae adult wasps at 15 °C and 10 °C for 1 week had no significant difference in terms of adult longevity, parasitism rate, and progeny compared with the control. By analysing the gene expression patterns and comparing the whole transcriptome of cold-treated A. calandrae adults (adults after cold storage at 15, 10, or 5 °C for 1 week, referred to as T2, T3, and T4, respectively, and adults without experiencing cold storage referred to as T1), a total of 1376, 9799, and 7745 differentially expressed genes (DEGs) were respectively identified (T1 vs T2, T1 vs T3, T1 vs T4). A total of 196 commonly up-regulated genes and 100 commonly down-regulated genes in T1 vs T2, T1 vs T3, and T1 vs T4 treatments were identified. A total of 6 modules composed of differentially co-expressed genes were identified by weighted gene co-expression network analysis (WGCNA). The Mebrown module was extremely associated with the T4 sample. Mebrown module of genes was found to be highly correlated with the metabolic process (217 genes), cell part (148 genes), and catalytic activity (225 genes). Four transcription factor genes, LOC111691805, LOC126386779, LOC108733382, and LOC108906572 were presented in Mebrown module as hub genes. The changes in gene expression indicated that A. calandrae can significantly upregulate the expression levels of abiotic related genes, such as the heat shock protein (Hsp 90) gene, cytochrome P450, and calnexin gene, etc., to cope with cold stress. The current results provide the molecular mechanisms and identify the key genes that may explain the adaptation of A. calandrae to cold stress.

How Wasps Recognize Their Eggs

Wasps are insects that many people tend to dislike. But have you heard that wasps perform really important services in nature, such as pest control and pollination, and that they can also serve as living indicators of environmental health? We can learn a lot from wasps. Most people do not know that wasps have a sophisticated communication system—they use their eyes to see, their antennas to smell, and their legs to feel vibrations. The bodies of adult and young wasps are covered by a mix of odors, which carry information about which family they belong to. We decided to do experiments to see if wasps can recognize their eggs because, to us, all wasp eggs look very similar. In this article, we will show you that wasp eggs carry odors that wasps can recognize, and this helps the entire colony to function properly.

Diversity of Parasitoid Wasps and Comparison of Sampling Strategies in Rice Fields Using Metabarcoding.

A comprehensive and precise evaluation of Arthropoda diversity in agricultural landscapes can enhance biological pest control strategies. We used Malaise traps and sweep nets to collect insects from three double-cropping paddy fields. DNA was extracted from the ethanol preservative of the Malaise traps and from tissue samples of selected parasitoid wasps. This was followed by amplification using DNA barcoding primers to prepare high-throughput sequencing libraries. We annotated a total of 4956 operational taxonomic units (OTUs), encompassing 174 genera and 32 families of parasitoid wasps. The ethanol filter method efficiently captured a wide range of information. However, the method has low resolution and may result in a reduced estimate of species abundance. Additional insect species were also identified in the parasitoid samples. This suggests that high throughput sequencing from adult parasitoid wasps can also detect host species, enabling a better understanding of host species and providing insights into food webs.

Phenology model development for Neodryinus typhlocybae: Evaluation of phenological synchrony with its host, Metcalfa pruinosa

The invasive species Metcalfa pruinosa has inflicted significant economic losses in various European and Asian regions. To combat this pest, the parasitoid wasp Neodryinus typhlocybae has been effectively introduced in Europe. Despite its success, research on the field occurrence patterns of N. typhlocybae, particularly its phenology, remains scarce. This study aims to develop a degree-day model for predicting the adult emergence of N. typhlocybae from overwintering cocoons and to assess the phenological synchrony between N. typhlocybae adults and the nymphal stages of M. pruinosa in Korea. In this study, we estimated the thermal parameters of N. typhlocybae under field temperatures and six constant temperatures (13.92, 17.71, 18.53, 20.53, 22.78, and 24.03 °C) conditions. The lower developmental temperature was estimated using the values of the coefficient of variation for the cumulative degree days of emerged individual adults. The estimated lower developmental threshold temperature was 12.3 °C. With this developmental threshold, a degree-day model was developed, and this model well-predicted emergence in field conditions. By simulating this developed model with the actual occurrence of the nymphal stages of its host, M. pruinosa, adult wasp emergence was estimated to be 1.5 weeks later than the first instar nymph of the host but faster than other nymphal stages of M. pruinosa. Thus, the findings in this study would be helpful in determining the possibility of establishing N. typhlocybae and improving the management efficiency of M. pruinosa.

Floral resources enhance fitness of the parasitoid Hadronotus pennsylvanicus (Hymenoptera: Scelionidae) but not biological control of its host Leptoglossus zonatus (Heteroptera: Coreidae).

The diet of adult parasitoid wasps is vital for their survival and reproduction. However, the availability of food resources, such as plant nectar, can vary widely in cropping systems, potentially affecting parasitoid fitness and thereby biological control of pests. The egg parasitoid Hadronotus pennsylvanicus (Ashmead) (Hymenoptera: Scelionidae) is a potential biological control agent of the pistachio pest Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae). While H. pennsylvanicus is known to attack L. zonatus eggs in California, USA, parasitism rates in orchards are highly variable. Floral resource provisioning has the potential to enhance parasitoid longevity and thus improve parasitism rates, leading to reduced pest densities. Here, a combination of field and laboratory studies was used to assess the influence of flowering groundcovers on the reproductive fitness of H. pennsylvanicus and the abundance of L. zonatus. Evaluated groundcovers included oat (Avena sativa L.), cowpea (Vigna unguiculata L.), white mustard (Sinapis alba L.), and buckwheat (Fagopyrum esculentum Moench). Under laboratory conditions, buckwheat and mustard provided the greatest benefit to female H. pennsylvanicus longevity. However, females provided a buckwheat diet produced the greatest number of offspring over the course of their lifetime. In field trials, flowering groundcovers did not influence the abundance of H. pennsylvanicus nor parasitism rates on L. zonatus. While the availability of floral resources can improve the reproductive fitness of H. pennsylvanicus, the use of groundcovers in pistachio did not enhance biological control of L. zonatus.

Relationship between Nest and Body Temperature and Microclimate in the Paper Wasp Polistes dominula.

The paper wasp Polistes dominula is a thermophilic species originating from the Mediterranean climate, but is now widely spread in Europe. They live in quite differing habitats; and as synanthropic species, they have been established in human settlement areas. They build a single small comb at protected places with a favorable microclimate. We measured the temperature of the wasps, the nests and their environment at typical nesting sides in Austria (Europe) in the temperate climate, in order to reveal relationships between nest and body temperature and the habitats' microclimate. The temperatures of the comb and of the wasps' body were in a wide range (~20-37 °C) above the ambient air temperature at the nest. This is an advantage as higher temperatures accelerate the development speed of the brood. However, the mean comb temperature did not exceed approximately 38.6 °C. This was managed by cooling efforts of the adult wasps. The ambient air temperature near the nest (~1-2 cm) was always clearly elevated above the ambient air temperature at a local standard weather station in the habitat. A comparison with climate-model-generated macroclimate data revealed the necessity of measuring microclimate data for a reliable description of the insects' thermal environment.

Improved effects of Helicoverpa armigera nucleopolyhedrovirus integrated with Campoletis chlorideae against H. armigera and impact of the virus on the parasitoid.

Combined use can be an effective measure to improve pest control by viruses and parasitic wasps. However, not all combinations of natural enemies show improved effects. Helicoverpa armigera nucleopolyhedrovirus (HearNPV) and Campoletis chlorideae Uchida are two important natural enemies of Helicoverpa armigera. This study aimed to investigate the combined effects of C. chlorideae and HearNPV against H. armigera larvae and the impact of HearNPV on C. chlorideae. The combination of HearNPV and C. chlorideae exerted increased mortality on H. armigera when C. chlorideae parasitized larvae one day after infection with HearNPV. C. chlorideae could distinguish between HearNPV-infected and noninfected larvae. Besides influencing host selection of C. chlorideae, HearNPV infection had negative effects on the development and reproduction of C. chlorideae. The developmental time of C. chlorideae was significantly prolonged and the percentage of emergence and adult eclosion of C. chlorideae was lower in infected hosts. The adult wasps were also smaller in body size, and female adults had fewer eggs when they developed in virus-infected hosts. HearNPV combined with C. chlorideae could improve the efficacy of biological control against H. armigera. The results provided valuable information on the importance of timing in the combined use of HearNPV and C. chlorideae for the biological control of H. armigera. © 2023 Society of Chemical Industry.

Adverse effects of the fungal biopesticide Beauveria bassiana on a predatory social wasp

Biopesticides are considered eco-friendly alternatives to synthetic agrochemicals. However, their impact on non-target organisms is still poorly understood. Social wasps, in particular, are a largely neglected group when it comes to risk assessment of plant protection products, despite the relevant ecological and economic services provided by these insects. In the present study, we evaluated the impact of a common biopesticide, the entomopathogenic fungus Beauveria bassiana, on the paper wasp Polistes dominula. We adopted a holistic approach in ecotoxicology by focusing not only on the detrimental effects on isolated individuals, but also on the whole colony. Both adult wasps belonging to different castes and immature larvae were topically exposed to a field-realistic concentration of fungal spores from the commercial strain of B. bassiana ATCC 74040 to assess the impact of the biopesticide on their survival, behavior and physiology. Our results showed that the fungus causes a number of adverse effects on P. dominula, that include increased mortality, altered locomotion and feeding rate, selective ejection of exposed larvae from nests, reduced oviposition rate and ovary development in foundresses, and colony failure. Our findings provide new insights on the often-neglected sublethal effects of pollutants that can jeopardize not only individual beneficial insects, but also the delicate social balance of their colonies and their valuable ecosystem services, highlighting that the natural origin of plant-protection products does not always guarantee environmental safety.

Functional characterization of Microplitis demolitor bracovirus genes that encode nucleocapsid components.

Understanding how bracoviruses (BVs) function in wasps is of broad interest in the study of virus evolution. This study characterizes most of the Microplitis demolitor bracovirus (MdBV) genes whose products are nucleocapsid components. Results indicate several genes unknown outside of nudiviruses and BVs are essential for normal capsid assembly. Results also indicate most MdBV tyrosine recombinase family members and the DNA binding protein p6.9-1 are required for DNA processing and packaging into nucleocapsids.

The Susceptibility of Bemisia tabaci Mediterranean (MED) Species to Attack by a Parasitoid Wasp Changes between Two Whitefly Strains with Different Facultative Endosymbiotic Bacteria.

In this study, two strains of the mitochondrial lineage Q1 of Bemisia tabaci MED species, characterized by a different complement of facultative bacterial endosymbionts, were tested for their susceptibility to be attacked by the parasitoid wasp Eretmocerus mundus, a widespread natural enemy of B. tabaci. Notably, the BtHC strain infected with Hamiltonella and Cardinium was more resistant to parasitization than the BtHR strain infected with Hamiltonella and Rickettsia. The resistant phenotype consisted of fewer nymphs successfully parasitized (containing the parasitoid mature larva or pupa) and in a lower percentage of adult wasps emerging from parasitized nymphs. Interestingly, the resistance traits were not evident when E. mundus parasitism was compared between BtHC and BtHR using parasitoids originating from a colony maintained on BtHC. However, when we moved the parasitoid colony on BtHR and tested E. mundus after it was reared on BtHR for four and seven generations, we saw then that BtHC was less susceptible to parasitization than BtHR. On the other hand, we did not detect any difference in the parasitization of the BtHR strain between the three generations of E. mundus tested. Our findings showed that host strain is a factor affecting the ability of E. mundus to parasitize B. tabaci and lay the basis for further studies aimed at disentangling the role of the facultative endosymbiont Cardinium and of the genetic background in the resistance of B. tabaci MED to parasitoid attack. Furthermore, they highlight that counteradaptations to the variation of B. tabaci defence mechanisms may be rapidly selected in E. mundus to maximize the parasitoid fitness.