Search Results (199)

The occurrence of the invasive Orange Spiny Whitefly (Aleurocanthus spiniferus) has expanded rapidly in Italy, prompting responses from both native and unintentionally introduced natural enemies. Through field monitoring, morpho-molecular identification, and phenological analysis, a multi-species parasitoid complex acting on this pest was revealed. In addition to the predominant activity of Eretmocerus iulii, this study reports the first European detection of Encarsia smithi, genetically confirmed as belonging to haplogroup I, a lineage previously associated with A. spiniferus in Asia. Occasional parasitization by Cales noacki was also observed. Seasonal patterns suggest a possible ecological complementarity between Er. iulii and E. smithi, which may contribute to the suppression of A. spiniferus populations. Although climatic variables showed weak correlations with infestation or parasitism rates, a slight positive relationship was observed between rainfall and whitefly abundance. The increasing biocenotic complexity, reflected by the diversity and interactions among parasitoid species, indicates an emerging ecological balance. These findings underscore the potential role of unintentional biological control in supporting agroecosystem resilience. Full article

Plants and insects are developing strategies to avoid each other’s defense systems. Host plants may release volatile compounds to attract the natural enemies of herbivores; insect pests may also select host plants that are deterrent to natural enemies to avoid such predation. Here we investigated whether the host plant preference of Hyphantria cunea correlates with the attractiveness of these plants to Chouioia cunea, a parasitoid wasp that serves as the primary natural enemy of H. cunea. We found Morus alba was the preferred host plant for female H. cunea. Although M. alba provided suboptimal nutritional value for H. cunea growth and development compared to other plants, it attracted fewer C. cunea relative to alternative host plants. Gas chromatography–mass spectrometry (GC–MS) coupled with gas chromatography–electroantennographic detection (GC-EAD) analysis identified six distinct compounds among the herbivore-induced plant volatiles (HIPVs) produced following H. cunea feeding. Notably, M. alba was the sole plant species that did not emit tridecane. These results suggest that H. cunea utilizes M. alba as a reduced predation enemy-free space, thereby minimizing parasitization by C. cunea. Our research emphasizes the importance of considering adaptive responses of herbivores within the context of multi-trophic relationships, rather than solely focusing on optimizing herbivore growth on the most nutritionally suitable plant host. Full article

The parasitoid wasp Dolichogenidea gelechiidivoris is a key koinobiont solitary endoparasitoid of the invasive agricultural pest Tuta absoluta. This study investigates both the morphological and molecular foundations of sex-specific olfactory differentiation in this species. Morphological analysis revealed that males possess significantly longer antennae (2880.8 ± 20.36 μm) than females (2137.23 ± 43.47 μm), demonstrating pronounced sexual dimorphism. Scanning electron microscopy identified similar sensilla types on both sexes, but differences existed in the length and diameter of specific sensilla. Transcriptomic analysis of adult antennae uncovered molecular differentiation, identifying 11 odorant-binding proteins (OBPs) and 20 odorant receptors (ORs), with 27 chemosensory genes upregulated in females and 4 enriched in males. Integrating morphological and molecular evidence demonstrates complementary sexual specialization in the olfactory apparatus of D. gelechiidivoris. Linking these findings to the potential functions of different sensilla types, as discussed in the context of prior research, provides crucial insights into the sex-specific use of volatile cues. These findings provide critical insights into the use of volatile signals in this highly relevant species for biological control targeting T. absoluta. Full article

A new species of Aprostocetus (Hymenoptera: Eulophidae), Aprostocetus bipolaris sp. nov., is recognized to be fortuitously present on a population of the invasive Eucalyptus (E. grandis × E. urophylla) gall wasp Ophelimus bipolaris Chen & Yao, in Guangxi, China. To classify this species, an integrated approach of morphological characteristics and molecular data was applied. The morphology of the new species is described and illustrated, and an identification key for female and male adults is also presented. Regarding phylogenetic analyses, the position of A. bipolaris sp. nov. within the Aprostocetus group of genera was reaffirmed based on 28S and COI gene sequences. All these lines of evidence indicate that A. bipolaris sp. nov. is a new species. Full article

Parasitoid wasps are vital for biological control, and while new species continue to be discovered, evaluating their biological characteristics is crucial for realizing their potential for pest management. Pachycrepoideus vindemiae (Rondani) (Hymenoptera: Pteromalidae) is a well-studied parasitoid of dipteran pests, while Trichomalopsis ovigastra Sureshan & Narendran (Hymenoptera: Pteromalidae) has been only morphologically described. To assess its biocontrol potential, we compared the biological traits of T. ovigastra and P. vindemiae using Drosophila melanogaster Meigen (Diptera: Drosophilidae) and Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) as hosts. T. ovigastra showed significantly higher parasitism rates, especially against B. dorsalis, where T. ovigastra achieved nearly 50% parasitism, compared to less than 0.3% by P. vindemiae. When using D. melanogaster as the host, no significant differences were observed between T. ovigastra and P. vindemiae in offspring sex ratio or adult longevity; however, T. ovigastra exhibited a shorter developmental duration and greater tolerance to temperature extremes, starvation, and desiccation. Notably, B. dorsalis has expanded its range from southern to northern China; however, no native parasitoids of this pest have been reported in the newly invaded northern regions. T. ovigastra, collected from northern orchards and capable of parasitizing B. dorsalis, thus shows promise as a biocontrol agent. These findings highlight the potential of locally occurring parasitoids, although field validation is still required. Full article

Trichogramma wasps, egg parasitoids widely used to control lepidopteran pests, have long eluded in-depth molecular mechanistic studies due to their minute size and genetic tool scarcity. While previous RNAi efforts were restricted to T. dendrolimi, we developed the first cross-species RNAi system for both T. dendrolimi and the previously intractable T. ostriniae. Temporal expression profiling identified white and laccase 2 as stage-specific RNAi targets, peaking during prepupal/pupal stages, which were tested across species and developmental stages using microinjection and soaking dsRNA delivery methods. Survival analysis prioritized soaking for T. dendrolimi prepupae/pupae, while microinjection was essential for T. ostriniae to bypass prepupal mortality during soaking. Concentration-dependent RNAi targeting the white gene achieved 85.61% transcript reduction in T. dendrolimi via soaking and 89.36% in T. ostriniae via microinjection at 2000 ng/μL, correlating with 64.06% and 32.09% white-eyed pupae, causing a significant reduction in eye pigments. For the laccase 2 gene, soaking at 2000 ng/μL induced 88.35% transcript reduction in T. dendrolimi and 73.31% in T. ostriniae, leading to incomplete cuticle tanning and sclerotization. This study resolves the long-standing challenge of genetic manipulation in Trichogramma wasps, providing a universally applicable framework to decipher parasitoid–host interactions at the molecular scale, which is useful for sustainable pest management strategies. Full article

This study reports the first complete mitochondrial genomes of three egg parasitoid wasps parasitizing Nilaparvata lugens—Pseudoligosita nephotetticum, Anagrus frequens, and Anagrus nilaparvatae. Genome sizes ranged from 15,429 to 15,889 bp, with all three mitogenomes displaying strong A + T bias, standard gene content, and characteristic strand asymmetries. While A. frequens and A. nilaparvatae exhibited conserved gene orders, extensive gene rearrangements, including multiple inversions in both protein-coding genes (PCGs) and tRNAs, were observed in P. nephotetticum. Codon usage analyses revealed a preference for codons ending in A or U. The non-synonymous (Ka) to synonymous (Ks) substitution ratio analysis identified signs of positive selection in multiple PCGs, particularly in atp8, nad6, and nad3, suggesting possible adaptive evolution related to host-searching behavior. Secondary structure analyses showed the loss of trnL1 in all Anagrus species, while trnS1 and trnR lacked the DHU arm, indicating possible derived traits in Mymaridae. Phylogenetic analysis was the first time to describe the relationship of the genus Anagrus within Mymaridae from the perspective of 13 protein genes. Furthermore, the grouping of (Pseudoligosita + Megaphragma) + Trichogramma was supporting the distinct evolutionary lineage of Pseudoligosita. This work provides new molecular resources and phylogenetic insight for Chalcidoidea, with implications for parasitoid evolution and biological control strategies. Full article

The chestnut gall wasp (Dryocosmus kuriphilus Yasumatsu) is an invasive pest that attacks species of the genus Castanea, inducing gall formation on buds and leaves, which can significantly reduce tree growth, fruiting, and overall chestnut production. Native to China, D. kuriphilus has become a serious threat to chestnut orchards worldwide. Torymus sinensis Kamijo, a parasitoid also originating from China, is highly specific to D. kuriphilus and is currently considered the most effective biological control agent against this pest. This study aimed to evaluate the establishment of T. sinensis as well as its effectiveness in controlling D. kuriphilus at release sites between 2020 and 2023. Releases of T. sinensis were conducted in the municipality of Bragança with a sex ratio of 120 females to 70 males. The parasitoids were randomly released across three chestnut trees with infestation levels ranging from moderate (26–50% of the canopy affected by galls) to very severe (>80% of the canopy affected). At each release site, 250 galls were collected annually, and 10% of these galls were dissected to calculate parasitism rates by T. sinensis. Results revealed a positive correlation between the monitoring year and the parasitism rate. Following the releases, parasitism rates increased gradually, reaching values between 15% and 40%. T. sinensis successfully established itself in chestnut orchards and parasitized D. kuriphilus, despite normal population fluctuations being observed across years and orchards. Full article

Aprostocetus nitens Prinsloo & Kelly (Hymenoptera: Eulophidae) was identified as one of four hymenopteran ectoparasitoids utilizing three erythrina gall wasps, Quadrastichus bardus, Q. erythrinae, and Q. gallicola) (Hymenoptera: Eulophidae) in the native eastern Africa. In Hawaiʻi, the eurytomid wasp, Eurytoma erythrinae Gates & Delvare (Hymenoptera: Eurytomidae), was introduced and approved for statewide release in 2008 to control the erythrina gall wasp (EGW) Q. erythrinae Kim. EGW has devastated the wiliwili trees, Erythrina sandwicensis Degener (Fabaceae), an ecologically and culturally important native Hawaiian tree species. However, the parasitoid’s impact on the galled inflorescences and shoots was not adequate to ensure adequate seed set and maturation for successful tree recruitment. Aprostocetus nitens was thus evaluated as a prospective natural enemy to enhance the biological control of EGW to further protect the wiliwili trees in Hawaiʻi. Both choice and no-choice host specificity tests were conducted on seven non-target gall formers in the Hawaii Department of Agriculture, Insect Containment Facility, and showed that the parasitoid was extremely specific to EGW. The potential for competition between this parasitoid and the established E. erythrinae was also investigated, showing that the release of a second parasitoid will potentially complement the success of the eurytomid wasp for control of EGW. Unlike what was found in the native region, the Hawaiian laboratory colony is thelytokous, producing only female offspring. The life cycle took 20.1 ± 0.28 days under the laboratory conditions. Non-ovipositing female survived for 102.5 ± 2.9 days when fed honey and laid eggs for 25.1 ± 2.3 days with average fecundity of 156.7 ± 22.3 offspring/female. This value is 3.9-fold higher than offspring produced by E. erythrinae. Aprostocetus nitens, host specificity, competition with E. erythrinae, and its tri-trophic association with 15 Erythrina host plants and 5 gall wasp assemblages in the native African regions were defined. Implications to reduce frequent galls on the native Erythrina plants and likely domination over E. erythrinae, are discussed. Full article

Entomopathogenic fungi (EPFs) can influence plant–insect interactions through complex molecular and chemical mechanisms. This study investigates how EPF treatment of tomato plants modulates volatile organic compound (VOC) emissions and subsequent trophic interactions between tomato plants, the herbivorous pest Phthorimaea absoluta, and the parasitic wasp, Trichogramma chilonis. Our results demonstrate that EPF-treated plants exhibited reduced attractiveness to adult P. absoluta moths, which were actively repelled by EPF-induced VOCs. Conversely, these same plants showed enhanced recruitment of the parasitoid T. chilonis, which demonstrated positive chemotaxis toward the modified VOC profile. Chemical analysis revealed significantly elevated emissions of key VOCs in EPF-treated plants, particularly (E)-β-Caryophyllene, β-phellandrene, and α-Phellandrene. This increase is correlated with enhanced production of defense-related phytohormones, including JA, SA, and JA-Ile, which may regulate VOC biosynthesis pathways. Behavioral response studies using synthetic VOCs and electroantennogram (EAG) measurements confirmed that these EPF-induced VOCs elicited strong olfactory responses in both insect species. To summarize, EPF treatment reshapes multitrophic interactions by strategically modulating plant VOC emissions and activating defense signaling pathways in tomato plants, providing new insights for potential applications in sustainable pest management strategies. Full article

New genes play a critical role in phenotypic diversity and evolutionary innovation. Parasitoid wasps, a highly abundant and diverse group of insects, parasitize other arthropods and exhibit remarkable evolutionary adaptations, such as evading host immune responses and exploiting host resources. However, the specific contributions of new genes to their unique traits remain poorly understood. Here, we identified 480 new genes that emerged after the Nasonia-Pteromalus divergence. Among these, 272 (56.7%) originated through DNA-mediated duplication, representing the largest proportion, followed by 77 (16.0%) derived from RNA-mediated duplication and 131 (27.3%) that arose de novo. Comparative analysis revealed that these new genes generally have shorter coding sequences and fewer exons compared to single-copy older genes conserved in the seven parasitoid wasps. These new genes are predominantly expressed in the reproductive glands and exhibit venom gland-biased expression. Notably, gene co-expression network analysis further identified that a new gene may act as a hub by interacting with older genes to regulate venom-related networks rather than directly encoding venom proteins. Together, our findings provide novel insights into the role of new genes in driving venom innovation in parasitoid wasps. Full article

Habrobracon hebetor is a globally acknowledged larval ectoparasitoid that is widely used to control lepidopteran pests. Wolbachia is a natural endosymbiont that regulates various aspects of the insect host biology. The ability of H. hebetor to paralyze and develop on lepidopteran larvae from five families was tested under laboratory conditions. Two lines of the wasp were used, “W+” containing a naturally occurring Wolbachia from the supergroup B, and “W−”, with the endosymbiont eradicated by antibiotic treatment, followed by propagation of 20 subsequent generations. The proportions of larvae in which host paralysis, as well as parasitoid oviposition, larval, pupal, and adult development were observed, were usually higher in W+ compared to W−. In Loxostege sticticalis, differences in these indices were not statistically significant. In Galleria mellonella, Mamestra brassicae, and Ostrinia nubilalis, some of the parasitism indices were significantly higher in W+ than in W−. In Bombyx mori and Plutella xylostella, H. hebetor could not complete its life cycle, but parasitism levels at the initial steps (from paralysis symptoms to the presence of larvae/pupae of the parasitoid) were 2–5 times lower in W− compared to W+ (p < 0.01). It can be suggested that the presence of Wolbachia is advantageous for H. hebetor, as it increases the success of parasitism in a broad range of lepidopteran hosts. Full article

This study explores the molecular mechanisms underlying diapause in the parasitoid wasp Telenomus remus (Nixon) (Hymenoptera: Platygastridae), a critical egg parasitoid for the biological control of the invasive pest Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). While effective in pest management, T. remus faces limitations in large-scale applications due to its short lifespan and low viability under storage conditions. Diapause, a state of developmental arrest, was successfully induced in T. remus using photoperiod manipulation (0L:24D), allowing for extended survival and improved storage potential. Transcriptome sequencing identified 2642 differentially expressed genes, with 617 involved in 284 enriched pathways, including calcium signaling and phototransduction. The study found that the expression levels of CBP1 and CBP2, genes encoding calcium-binding proteins, were significantly downregulated during diapause. As key regulators in calcium ion-mediated signal transduction pathways, the downregulation of CBP1 and CBP2 may lead to the suppression of intracellular calcium signaling, thereby affecting light signal transduction and energy metabolism regulation. This suggests that during diapause, insects may reduce calcium signaling activity to suppress physiological functions, maintain a low metabolic state, and decrease sensitivity to environmental stimuli. Additionally, ARR genes still exhibited differential expression, further supporting their potential role in phototransduction and diapause regulation. Full article

Related species of parasitoid Hymenoptera often coexist on a certain host, but many details of interactions between these organisms remain unclear. The present review summarizes the main existing concepts and facts and suggests principal patterns and mechanisms that allow for the coexistence of several members of a particular parasitoid genus at the expense of the same host. Although the successful introduction of exotic parasitic wasps into the existing ecosystems often leads to the competitive displacement of related parasitoids, mere spatial and/or temporal niche partitioning between these insects is also possible. Nevertheless, many cases of coexistence of related wasp species on the same host defy simple explanations since they apparently result from complex interactions between the host and its parasitoids. The main characteristics of the oviposition process, i.e., egg volume, fecundity, and duration of the egg-laying period, are likely to correlate with other basic features of life-history strategies in parasitoid Hymenoptera. Specialist parasitic wasps often aggregate over the host patches, whereas generalists can be randomly distributed, thus reducing the degree of interspecific competition among parasitoids. However, some of the coexisting parasitic wasps, usually the weakest competitors, must also have access to enemy-free space to survive. Full article

Unusual membrane-bound particles are present in the venom of the parasitoid wasps that parasitize Drosophila melanogaster. These venom particles harbor about 400 proteins and suppress the encapsulation of a wasp egg. Whereas the proteins in the particles of Leptopilina boulardi venom modify host hemocyte properties, those in L. heterotoma kill host hemocytes. The mechanisms underlying this differential effect are not well understood. The proteome of the L. heterotoma venom particles has been described before, but that of L. boulardi has not been similarly examined. Using sequence-based programs, we report the presence of conserved proteins in both proteomes with strong enrichment in the endomembrane and exosomal cell components. Extracellular vesicle markers are present in both proteomes, as are numerous toxins. Both proteomes also contain proteins lacking any annotation. Among these, we identified the proteins with structural similarity to the ADP-ribosyltransferase enzymes involved in bacterial virulence. We propose that invertebrate fluids like parasitoid venom contain functional extracellular vesicles that deliver toxins and virulence factors from a parasite to a host. Furthermore, the presence of such vesicles may not be uncommon in the venom of other animals. An experimental verification of the predicted toxin functions will clarify the cellular mechanisms underlying successful parasitism. Full article