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Diglyphus species are ecologically and economically important on agromyzid leafminers. In 2018, a thelytokous species, Diglyphus wani Liu, Zhu & Yefremova, was firstly reported and described. Subsequently, the arrhenotokous D. wani were discovered in Yunnan and Guizhou Provinces of China. We compared the morphological characteristics of thelytokous and arrhenotokous strains. However, the females of two strains had a strongly similar morphology and showed subtle differences in fore- and hind-wings. The difference was that forewing of arrhenotokous female was with denser setae overall, showing that costal cell with 2 ~ 4 rows of setae on dorsal surface and the setae of basal cell with 15 ~ 21 hairs and forewing of thelytokous female was with two rows of setae on dorsal surface and basal cell with 10 ~ 15 hairs generally. The setation beneath the marginal vein of the hind-wing of arrhenotokous female is denser than the same area of thelytokous female. To explore the genetic divergence between thelytokous and arrhenotokous strains of D. wani , the mitochondrial and nuclear gene were applied and sequenced. The polygenic analyses revealed that two strains can be distinguished by COI, ITS1 and ITS2. The mean sequence divergence between the two strains was 0.052, 0.010 and 0.007, respectively. Nevertheless, the 28S gene was unfeasible due to its containing a sharing haplotype between different strains. The two strains of D. wani are dominant parasitoids against agromyzid leafminers and such effective discernible foundation provides future in-depth studies on biological characteristics, along with insight into field application of two strains of D. wani .

The recent incursions of three agromyzid leafminers (Liriomyza huidobrensis, L. sativae, and L. trifolii) into Australia pose a significant threat to horticultural production. Outbreaks of these polyphagous pests are consistently associated with the disruption of their parasitoids caused by the widespread use of non-selective insecticides and to increasing pesticide resistance in these agromyzids. An analysis of the international literature for records of parasitoids associated with L. huidobrensis, L. sativae, and L. trifolii revealed that they are attacked by a similar profile of parasitoid families: Eulophidae (63% of records), Braconidae (19%), Pteromalidae (9%), and Figitidae (8%). Diglyphus isaea, Neochrysocharis formosa and Hemiptarsenus varicornis (all already recorded in Australia) were the most commonly reported parasitoids worldwide. These species, along with Australia’s broader parasitoid fauna, will play an important role in managing invasive Liriomyza species, provided insecticide use does not disrupt their populations. However, key knowledge gaps remain, especially regarding the taxonomy of local parasitoids, their potential use in conservation biocontrol programs, and the local landscape features that support parasitoid populations. The use of various species in augmentative releases is considered, including constraints and opportunities related to strain selection and the potential use of thelytokous strains for mass-rearing.

Field trials were carried out for two seasons in two sites (Sagana and Naromoru, Central province of Kenya) to evaluate the prospects of endophyte isolates of Beauveria bassiana (Balsamo) Vuillemin G1LU3 and Hypocrea lixii Patouillard F3ST1 for the control of Liriomyza leafminer in common bean Phaseolus vulgaris L. crops through seeds inoculation. Autodissemination device (AD) treated with conidia of Metarhizium anisopliae (Metschnikoff) Sorokin ICIPE 20 was also added as a treatment. Leafminer infestation was not significantly different during the first season but was higher in the controls than in endophtyte treatments at both sites during the second season. Three key Liriomyza species [( L. huidobrensis Blanchard, L. sativae Blanchard and L. trifolii (Burgess)] and six parasitoid species [( Opius dissitus Muesebeck, Phaedrotoma scabriventris Nixon, Diglyphus isaea Walker, Neochrysocharis formosa Westwood, Hemiptarsenus varicornis Girault and Halticoptera arduine (Walker)] were identified during the trials. Leafminer infestation, number of pupae, leafminer flies and parasitoids emergence and yield were the parameters evaluated. Both isolates successfully colonized different parts of P. vulgaris plants, although the colonization was higher with H. lixii F3ST1 than B. bassiana G1LU3 at both sites. The mean number of pupae from the infested leaves varied between 141–252 and 331–416 in endophyte and control treatments, respectively, during the first season and from 110–223 to 366–523, respectively, in endophyte and control treatments during the second season. There were no significant differences among the treatments in the number of parasitoids that emerged from pupae. Higher yield of P. vulgaris seeds was obtained in endophyte than in control treatments. The inclusion of AD treatment did not have significant effect on all the parameters evaluated, except yield. Results of the present study suggest that both fungal isolates hold potential for pest management and could be considered for the control of leafminer flies. However, there is the need to confirm these results on large-scale trials.

The assemblage of hymenopteran parasitoids associated with the invasive lime leaf miner, Phyllonorycter issikii (Lepidoptera, Gracillariidae), developing on the small-leaved lime ( Tilia cordata ) was studied in Perm krai and in the Republic of Bashkortostan in 2019. Sixteen species of parasitoids of Ph. issikii were recognized: Diglyphus isaea , Elachertus fenestratus , Hyssopus geniculatus , Pnigalio agraules , P . mediterraneus , Sympiesis dolichogaster , S. gordius , S. sericeicornis , Chrysocharis laomedon , Ch. nephereus , Ch. pentheus , Ch .  pubens , Ch. pubicornis , Ch . submutica , Minotetrastichus frontalis (Eulophidae), and Pholetesor circumscriptus (Braconidae). Three species, Diglyphus isaea , Chrysocharis pubens, and Ch . submutica (Eulophidae), were reported as parasitoids of the lime leaf miner for the first time. The roles the complex of parasitoids played in the mortality of the miner were negligible. The mortality ranged from 1.3 ± 0.3 (Perm) to 23.7 ± 3.3% (village of Tolbazy).

Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2(nd) and 3(rd) instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression.

Eulophidae and Pteromalidae are parasitic wasps with a global distribution and import for the biological control of pests. They can be distributed in different altitude regions, but their morphological and genetic adaptations to different altitudes are unclear. Here, we collected specimens that belong to Eulophidae and Pteromalidae from various altitudinal gradients, based on integrated taxonomic approaches to determine the species composition, and we analyzed their body shape and size from different altitudes using geometric morphometrics. Then, we performed an analysis of the D. isaea population’s haplotype genes to illustrate their genetic diversity. As a result, eight species that belong to two genera, Diglyphus Walker (Eulophidae) and Pachyneuron Walker (Pteromalidae), were identified, including two newly recorded species from China (D. chabrias and D. sabulosus). Through a geometric morphometrics analysis of body shape, we found that a narrow forewing shape and a widened thorax are the significant characteristics of adaptation to high-altitude environments in D. isaea and P. aphidis. Additionally, the body size studies showed a principal relationship between centroid size and altitude; the size of the forewings and thorax increases at higher altitudes. Next, using haplotype analysis, 32 haplotypes were found in seven geographic populations with high genetic diversity of this species. Our research provides preliminary evidence for the morphological and genetic diversity adaptation of parasitic wasps to extreme environments, and these data can provide important references for investigations on the ecological adaptability of parasitic wasps.

Diglyphus Walker, 1844 (Hymenoptera: Eulophidae) is an economically important genus including species acting as biocontrol agents against agromyzid leafminer pests. A new species of Diglyphus , Diglyphus difasciatus Liu, Hansson & Wan, sp. nov. , was discovered during the identification of agromyzid leafminers and their associated parasitoid wasps collected from 2016 to 2022 in China, based on morphological characteristics and molecular analyses of COI, ITS2 and 28S genes. Diglyphus difasciatus is similar to D. bimaculatus Zhu, LaSalle & Huang, distinguished by two interconnected infuscate vertical bands on the fore wing and the color of the scape. Molecular data support D. difasciatus and D. bimaculatus as two different species. The mean genetic distances between D. difasciatus and D. bimaculatus were 11.33%, 8.62%, and 0.18%, based on the COI, ITS2, and 28S genes, respectively.

In Hymenoptera parasitoids, the reproductive mode is arrhenotoky, while a few species reproduce by thelytoky. The thelytoky of Hymenoptera parasitoids is generally genetically determined by the parasitoids themselves or induced by bacteria, including Wolbachia, Cardinium, and Rickettsia. Diglyphus wani (Hymenoptera: Eulophidae), a recently reported thelytokous species is a main parasitoid attacking agromyzid leafminers. To assess whether endosymbionts induce thelytoky in D. wani, we performed universal PCR detection and sequenced the V3-V4 region of 16S ribosomal RNA gene. In addition, bacteria were removed through high-temperature and antibiotic treatments, and the localized bacteria were detected using FISH. Based on general PCR detection, Wolbachia, Cardinium, Rickettsia, Arsenophonus, Spiroplasma, and Microsporidia were absent in laboratory and field individuals of thelytokous D. wani. Furthermore, 16S rRNA gene sequencing revealed that the dominant endosymbionts in thelytokous D. wani were not reproductive manipulators. High-temperature and antibiotic treatment for five consecutive generations cannot reverse the thelytokous pattern of D. wani, and no male offspring were produced. Moreover, no bacterial spots were found in the ovaries of D. wani. Thus, it is considered that the thelytoky of D. wani does not result in the presence of endosymbionts. This species is thus the second reported eulophid parasitoid whose thelytoky appears not to be associated with endosymbionts.

The tiger-fly Coenosia attenuata Stein (Diptera: Muscidae: Coenosiini) is a generalist predator that preys on several pests of greenhouse crops and is considered a biological control agent in the Mediterranean region. Previous behavioural observations identified its preferred prey, but a more in-depth evaluation will benefit from using Polymerase Chain Reaction amplification of prey DNA remains in the gut of this predator. To evaluate the rate of decay and suitability of this method for use in the field assessments, we carried out a laboratory feeding calibration experiment on 355 females of C. attenuata, which were killed at different intervals of time after ingestion (10 time points from 0 to 48 h). The prey species tested were: Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae: Trialeurodini), Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), Diglyphus isaea (Walker) (Hymenoptera: Eulophidae: Cirrospilini), Bradysia impatiens (Johannsen) (Diptera: Sciaridae) and Drosophila mercatorum Patterson & Wheeler (Diptera: Drosophilidae: Drosophilini). Based on a probit model, amplification success of prey DNA declined exponentially with increasing time after ingestion. The half-time molecular detection differed between species, ranging from an average of 5 h for T. vaporariorum and D. isaea, 6 h for B. impatiens, 15 h for L. huidobrensis to more than 40 h for D. mercatorum. This study confirmed the feasibility of using DNA based detection to identify prey species in the gut contents of C. attenuata and provided calibration curves for a better understanding of predation activity in this agroecosystem.

It has been established that herbivore populations can be structured by apparent competition, even if they do not compete directly for resources. But we lack evidence on the mechanisms behind such indirect competition. This study shows that temporal asynchronies in emergence time lead to apparent competition via shared natural enemies in a leafminer-parasitoid community. We present three kinds of evidence on mechanisms driving apparent competition. First, we conducted a two-year population census of Liriomyza helianthi and Calycomyza platyptera , along with all associated parasitoids, at seven sites in the Californian Central Valley, USA. We then assessed C. platyptera parasitism on 16 vegetation islands, half with experimental removal of early-season L. helianthi populations. Finally, we examined parasitoid host preference between leafminer species. We found that Liriomyza helianthi populations emerged approximately one month before C. platyptera . Experimental removal of L. helianthi populations in the early summer led to a 60%% reduction in parasitism of C. platyptera . We found no evidence of differential parasitoid preference for host species. The findings suggest that temporal asynchrony can lead to negative effects on later-emerging species and that such indirect competition may be a major structuring force in herbivore communities.