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A new species of Mymaromma , M. menehune sp. nov. , is described from the Hawaiian Islands. It was found emerging as a solitary endoparasitoid from eggs of a Lepidopsocus sp. (Psocodea: Lepidopsocidae) on branches of Ficus microcarpa (Moraceae) on the island of O‘ahu. This the first host record for the superfamily Mymarommatoidea, coming almost exactly 100 years after the first extant species of Mymarommatidae was described.

Spotted-wing Drosophila, Drosophila suzukii (Matsumura, 1931), is an economic pest of thin-skinned fruit crops. Its control has commonly been carried out through chemical methods. However, given the need to develop safer and environmentally friendly management alternatives, the pupal endoparasitoid Trichopria anastrephae Lima stands out as a potential biological control agent. However, the lack of information on the mass rearing of this parasitoid limits its use. Thus, the objective of our study was to provide information that is useful for rearing T. anastrephae using D. suzukii as a host. The effects of pupal age, exposure time, and pupal density on the parasitism rate were examined, as was the effect of honey provision for extending adult parasitoid longevity. Exposing 15 12-h-old pupae per female for 24 h resulted in higher parasitism rates and a greater number of emerged parasitoids. Males and females of T. anastrephae fed with pure honey (100%) or honey diluted to 50% in water lived longer compared to those fed 10% honey, no food, or only water.

The invasive spotted wing drosophila, Drosophila suzukii Matsumura (Dipt.: Drosophilidae), a native of East Asia, has widely established in North America and Europe, where it is a serious pest of small and stone fruit crops. The lack of effective indigenous parasitoids of D. suzukii in the recently colonized regions prompted the first foreign exploration for co-evolved parasitoids in South Korea during 2013 and 2014. We collected the larval parasitoids Asobara japonica Belokobylskij, A . leveri (Nixon) and A. brevicauda Guerrieri & van Achterberg (Hym.: Braconidae) , Ganaspis brasiliensis (Ihering), Leptopilina japonica japonica Novković & Kimura and L. j. formosana Novković & Kimura (Hym.: Figitidae); and the pupal parasitoids Pachycrepoideus vindemiae (Rondani) (Hym.: Pteromalidae) and Trichopria drosophilae Perkins (Hym.: Diapriidae). From UC Berkeley quarantine records, percentage parasitism ranged from 0 to 17.1 % and varied by geography, season, and collection methods. Asobara japonica was the most common parasitoid species. Higher numbers of parasitoids were reared from field-picked fruit as opposed to traps baited with uninfested fruit. Quarantine bioassays confirmed that A. japonica , G. brasiliensis , L. j . japonica , P. vindemiae , and T. drosophilae developed from D. suzukii . Female individuals of the endoparasitoid, A. japonica, were larger when reared on the larger D. suzukii larvae compared with those reared on the smaller larvae of D. melanogaster Meigen. Larger parasitoid size was associated with longer developmental time. Several of the South Korean parasitoid species have the potential for use in classical biological control and may contribute to the suppression of D. suzukii in the newly invaded regions.

Current management strategy of the invasive fruit fly Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) exploits different tools but relies mainly on chemical control. In the invaded areas, the local natural enemy community mostly consists of generalist pupal parasitoids unable to control the pest efficiently. Conversely, in the pest native area, there are more specialized sympatric larval parasitoids attacking D. suzukii . Following foreign explorations and quarantine risk assessments, the larval endoparasitoid Ganaspis brasiliensis (Ihering) (Hymenoptera: Figitidae) was selected as the best candidate for classical biological control programs. In 2021, the first ever propagative biocontrol program using a Japanese G1 lineage of G. brasiliensis started in Italy. Here we report the results of the first year of releases in the province of Trento (Northeast Italy), wherein G. brasiliensis was released in 12 locations. Pre- and post-release samplings on fresh and fallen fruits were performed around the release points to assess the recapture rate, the impact of the exotic parasitoid on D. suzukii and its potential interactions with local non-target species. After releases, G. brasiliensis was recovered at 50% of the locations. The exotic parasitoid only emerged from D. suzukii , mostly from fresh fruit still on the plant. Post-overwintering monitoring revealed the presence of a four G. brasiliensis individuals at two release locations.

Phymastichus coffea LaSalle (Hymenoptera:Eulophidae) is an adult endoparasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera:Curculionidae:Scolytinae), which has been introduced in many coffee producing countries as a biological control agent. To determine the effectiveness of P. coffea against H. hampei and environmental safety for release in Hawaii, we investigated the host selection and parasitism response of adult females to 43 different species of Coleoptera, including 23 Scolytinae (six Hypothenemus species and 17 others), and four additional Curculionidae. Non-target testing included Hawaiian endemic, exotic and beneficial coleopteran species. Using a no-choice laboratory bioassay, we demonstrated that P. coffea was only able to parasitize the target host H. hampei and four other adventive species of Hypothenemus : H. obscurus, H. seriatus, H. birmanus and H. crudiae. Hypothenemus hampei had the highest parasitism rate and shortest parasitoid development time of the five parasitized Hypothenemus spp. Parasitism and parasitoid emergence decreased with decreasing phylogenetic relatedness of the Hypothenemus spp. to H. hampei , and the most distantly related species, H. eruditus , was not parasitized. These results suggest that the risk of harmful non-target impacts is low because there are no native species of Hypothenemus in Hawaii, and P. coffea could be safely introduced for classical biological control of H. hampei in Hawaii.

Parasitoids modulate host development for the survival of their offspring, but the mechanisms underlying this phenomenon remain largely unknown. Here, we found that the endoparasitoid Cotesia vestalis disrupted the larval-larval ecdysis in its host Plutella xylostella by the 20-hydroxyecdysone (20E) synthesis pathway. After parasitization by C. vestalis , the 20E peak of host larvae disappeared before the onset of ecdysis and the expression of ecdysone synthesis genes was significantly downregulated. We further found that a Cotesia vestalis bracovirus (CvBV) gene CvBV_28 − 5 was transiently high-level expressed prior to the host’s 20E peak, enabling the precise suppression of this critical developmental signal. Consistently, the knockdown of CvBV_28 − 5 affected the expression of 20E response transcription factors in the cuticle and several ecdysis-related genes. Furthermore, we found that CvBV_28 − 5 bound directly to the Raf, a MAP3K member of the MAPK pathwaythat functions as a critical regulator of ecdysone synthesis genes in hosts. Collectively, our results provide the first evidence that parasitoids modulate host ecdysis by affecting MAPK-20E signaling during a defined developmental window and provide novel insights into the mechanism of parasitoid regulation of host development.

The coexistence and efficiency in pest control of introduced and native parasitoids can be challenging. Continuous observations of the cohabitation of parasitoid species could confirm the persistence of the introduced parasitoid in the ecosystem under co-existence scenarios. This study provides an example of such a co-existence for biocontrol of the invasive pest, Phthorimaea absoluta (Meyrick) (Lepidoptera: Gelechiidae). Two parasitoids, the introduced endoparasitoid Dolichogenidea gelechiidivoris (Marsh) (Hymenoptera: Braconidae) and the native ectoparasitoid Bracon nigricans Szépligeti (Hymenoptera: Braconidae) were released in cages containing a tomato plant infested with P. absoluta . Parasitism and killing rate of P. absoluta by both parasitoid species, and the parasitoid and P. absoluta population were monitored weekly. The parasitoid species coexisted for seven weeks in the experimental units. Parasitism by D. gelechiidivoris was significantly affected by the presence of B. nigricans, with 73% and 22% parasitism in the absence and presence of B. nigricans, respectively. Parasitism by B. nigricans was not affected by its co-existence with D. gelechiidivoris . The number of D. gelechiidivoris adults increased eight-fold in five weeks in the absence of B. nigricans , while less than the initial number of adults were present in co-existence with B. nigricans . The P. absoluta infestation declined from the fifth week to 98% lesser than the control in all the treatments, either D. gelechiidivoris or B. nigricans as standalone treatments, as well as in combination. Since B. nigricans negatively affected D. gelechiidivoris population growth, releases of this introduced parasitoid should be considered with caution in areas where B. nigricans occurs.

     Microbiomes play vital roles in insect fitness and health and can be influenced by interactions between insects and their parasites. Many studies investigate the microbiome of free-living insects, whereas microbiomes of endoparasitoids and their interactions with parasitised insects are less explored. Due to their development in the constrained environment within a host, endoparasitoids are expected to have less diverse yet distinct microbiomes. We used high-throughput 16S rRNA gene amplicon sequencing to characterise the bacterial communities of Dipterophagus daci (Strepsiptera) and seven of its tephritid fruit fly host species . Bacterial communities of D. daci were less diverse and contained fewer taxa relative to the bacterial communities of the tephritid hosts. The strepsipteran’s microbiome was dominated by Pseudomonadota (formerly Proteobacteria) (> 96%), mainly attributed to the presence of Wolbachia , with few other bacterial community members, indicative of an overall less diverse microbiome in D. daci . In contrast, a dominance of Wolbachia was not found in flies parasitised by early stages of D. daci nor unparasitised flies . Yet, early stages of D. daci parasitisation resulted in structural changes in the bacterial communities of parasitised flies. Furthermore, parasitisation with early stages of D. daci with Wolbachia was associated with a change in the relative abundance of some bacterial taxa relative to parasitisation with early stages of D. daci lacking Wolbachia . Our study is a first comprehensive characterisation of bacterial communities in a Strepsiptera species together with the more diverse bacterial communities of its hosts and reveals effects of concealed stages of parasitisation on host bacterial communities.

The larval endoparasitoid Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae) is a biocontrol agent against the South American tomato leafminer, Phthorimaea absoluta (Meyrick) (Lepidoptera: Gelechiidae). Effective breeding protocols and storage methods ensure the availability of high-quality organisms for commercialization and field release. To optimize mass rearing programs, we evaluated the effects of P. dignus pupae cold storage under different temperature conditions and time periods. Two conditions were tested: 10 °C for four weeks and 13 °C for three weeks. We assessed flight capacity, pupal development time, adult emergence percentage, sex ratio of emerging adults, female survival rate over seven days, parasitism percentages using P. absoluta larvae, and sex ratio of the F1 generation. Morphometric traits of emerging females were also examined. Results indicated that emergence exceeded 60% under both conditions, with no impact on flight capacity or sex ratio. However, storage at 10 °C for four weeks significantly delayed pupal development and reduced parasitism percentages, with a male-biased progeny. Morphological analysis showed slight changes in wing size but no significant abnormalities. We conclude that short-term storage at 13 °C for three weeks is suitable for P. dignus rearing programs to support augmentative releases.

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.