The Encyrtidae encompass large group of insects widely used in the biocontrol programs of scale insects (Hemiptera: Coccoidea). Here we investigated antennal sensory system organization of Anagyrus vladimiri females, a species widely used as a biocontrol agent of Planococcus spp. and Pseudococcus spp. Ultrastructural investigations with scanning (SEM) and transmission (TEM) electron microscopy revealed filiform antennae made of nine segments. The scape was enlarged and paddle-like, compared to the other antennomeres. The club was mono-segmented and housed the highest number of sensilla. On the antennae, eight morphologically different types of sensilla were recorded; sensilla trichoidea I, trichoidea II, chaetica I, chaetica II, grooved peg sensilla, campaniform sensilla, multiporous plate sensilla, multiporous basiconic sensilla. The sensilla belonged to the major types sensilla types (olfactory, gustatory, thermos-hygroreceptor). The sensilla trichoidea I and multiporous plate sensilla were the most abundant types. The potential functional role of each sensillum was discussed.

Ceratitis capitata (Wiedemann) (medfly) strongly affects Argentinean fruit production and export. Augmentative biological control using the exotic parasitoid Diachasmimorpha longicaudata (Ashmead) is currently applied. The ability to find and parasitize medfly larvae on a wide diversity of fruit host species is a key issue to be analyzed. This research assessed the effect of the physical features of fruit on the preference of foraging D. longicaudata females and the influence of varying release density on parasitoid performance as a pest mortality factor in three fruit species. Trials were performed inside field cages under semi-arid environmental conditions in Argentina's central–western fruit-growing region. Sweet orange, peach, and fig were tested. Fruits were inoculated with third-instar larvae of the Vienna-8 temperature-sensitive lethal medfly strain. Naïve, 5-d-old mated D. longicaudata females were released in cages at 20, 40, 80 and 160 parasitoid densities. The highest levels of medfly mortality and parasitoid emergence were recorded in fig and peach, although D. longicaudata also induced mortality in orange, a fruit with few physical features favorable to parasitism. The medfly mortality in all fruit host species significantly increased with increased parasitoid females released into field cages. Diachsmimorpha longicaudata has high potential as a medfly biocontrol agent.

The modifications in planting structure and continuous land use adjustments have significant implications for the structure, diversity, and functioning of arthropod communities in farmland landscapes, particularly regarding the biological control of pest insects by natural enemy species. Therefore, there is an urgent need to comprehensively and accurately assess insect community diversity in croplands. In this study conducted between 2022-2023, we utilized Malaise traps and sweep netting to collect insects from three different double-cropping paddy fields. We extracted DNA from preservative ethanol of Malaise traps and tissue samples of selected parasitoid wasps, followed by amplification using DNA barcoding primers to prepare high-throughput sequencing libraries. As a result, we annotated a total of 4956 operational taxonomic units (OTUs) belonging to 174 genera and 32 families of parasitoid wasps. Our findings demonstrate that the ethanol filter method efficiently captures a wide range of information diversity. However, it demonstrates a lower resolution and may result in a reduction of species abundance. Furthermore, we have identified additional insect species in the parasitoid samples. This demonstrates that high throughput sequencing from adult parasitoid wasps can effectively detect host specie, enabling a comprehensive understanding of host species and providing novel insights into food web construction.

Phenacoccus manihoti (Hemiptera: Pseudococcidae), is an invasive pest that is very detrimental to cassava cultivation in Indonesia. Control efforts by utilizing natural enemies of the parasitoid have succeeded in overcoming the cassava mealybug in 25 countries such as in Africa and Thailand. The purpose of this study was to specifically evaluate the potential for parasitoid species associated with the mealybug P. manihoti by (1) determining the level of parasitization against mealybugs on various varieties of cassava, (2) determining parasitoid preference for P. manihoti instars, and (3) determining the type of parasitoid. This study was undertaken in the field to re-evaluate the kinds of parasitoids associated with cassava pests, and in the laboratory to assess the amount of parasitization, predilection, and functional response of parasitoids to P. manihoti population density. The findings revealed three of parasitoids linked with P. manihoti in the field: Anagyrus lopezi, Acerophagus sp., and Blepyrus sp. The parasitoid A. lopezi had the greatest parasitization rate in the field, which was 18.67 %. Furthermore, the parasitoids A. lopezi and Blepyrus sp. preferred 3rd instar nymphs, but Acerophagus sp. preferred 2nd instar nymphs. The parasitoid A. lopezi demonstrated a type-III functional response, while Acerophagus sp. and Blepyrus sp. demonstrated a type-II functional response. The handling capacity (Th) of A. lopezi is the shortest at 3.42 minutes. This work is a comprehensive study of the parasitoid A. lopezi's potential as a biological agent, highlighting how it effectively suppresses P. manihoti on various cassava varieties in Bali, providing an inexpensive, environmentally friendly, and applicable control in tropical countries.

The genus Dirphys Howard is synonymized with Encarsia Förster syn. n. and treated as a species-group of Encarsia, referred to henceforth as the Encarsia mexicana species-group. The monophyly of Encarsia is discussed in relation to Dirphys. The new synonymy is based on phylogenetic analyses of the nuclear ribosomal 28S-D2 gene region (43 taxa, 510 bp). The Encarsia mexicana species-group is recovered as strongly monophyletic within Encarsia. All species of the Encarsia mexicana species-group are revised. The group includes six previously described species, and fourteen newly described species. All species are described (or redescribed) and illustrated. Detailed distributional data, and, where available, plant associate and host records are provided for all species. Encarsia myartsevae Kresslein & Polaszek nom. nov. is here proposed as a replacement name for Encarsia mexicana Myartseva, now preoccupied by Encarsia mexicana (Howard). A dichotomous identification key, supplemented by an online multiple-entry key, is provided for all species.

Temperature is the abiotic factors that strongly influence the biology and behavior of insects. Thus, we assessed the development of the egg parasitoids, Ooencyrtus submetallicus and Telenomus podisi, parasitizing eggs of the brown stinkbug, Euschistus heros, at different temperatures, in addition to estimating the average number of generations using temperature records for seven representative soybean producing regions in Brazil. The comparative biology study conducted evidenced that O. submetallicus and T. podisi had similar percentages of parasitism and emergence, life cycle duration (egg-adult), and longevity. The sex ratio and the number of adult parasitoid emerged per parasitized egg was superior for O. submetallicus. The study of thermal requirements evaluated temperatures of 16, 19, 22, 25, 28, 31, and 33 °C. Ooencyrtus submetallicus and T. podisi developed at temperatures between 16 and 31°C. The lower temperature (Tb) threshold for O. submetallicus and T. podisi was 9.3° and 6.7°C, while the thermal constant (K) was 336.9 and 272.7 degree days, respectively. The estimated average number of generations per year for both parasitoids was greater than the pest E. heros. Ooencyrtus submetallicus and T. podisi exhibited the same biological capacity to parasitize and to develop parasitizing E. heros eggs under laboratory studied conditions. The temperature range between 16° and 33 °C was favourable for the development of both parasitoids parasitizing E. heros eggs.

Thermal variations affect tri-trophic interactions involving plants, herbivores, and parasitoids, causing a mismatch between their phenological cycles. In the current environmental context of climate change, climatic factors can undergo profound and sudden changes, such as sudden hot or cold snaps. Here we show that episodes of short but sustained low temperatures have increased, mainly in the month of May, in the last two decades. We subjected galls induced by Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus to cold stress to assess if and how the pest and its parasitoids were affected. Over the course of two years seasonal parasitism, parasitism rates, the relative abundance of each parasitoid species, and mortality of ACGW were calculated. We found that the cold treatment affected both pest and parasitoids, resulting in a reduction in emerging ACGWs and differing ratios of species within the parasitoid community. The striking example was the change in the relative frequency of three species of Eupelmus spp. and of Mesopolobus tibialis, which doubled in thermally-stressed galls in all chestnut fields. The thermal effects on the development of the host and the direct effects of cold temperatures on the surface of galls (i.e., humidity or hardness of the galls) warrant further research in this direction.

Diatoms are single-celled photosynthetic eukaryotes responsible for CO2 fixation and primary production in aquatic ecosystems. The cosmopolitan marine diatom Coscinodiscus granii can form seasonal blooms in coastal areas and interact with various microorganisms, including the parasitic oomycete Lagenisma coscinodisci. This unicellular eukaryote is mainly present in the northern hemisphere as an obligate parasite of the genus Coscinodiscus. Understanding the interplay of abiotic factors such as temperature and biotic factors like parasitism on algal physiology is crucial as it dictates plankton community composition and is especially relevant in climate change. This study investigates the impact of two temperatures, 13°C and 25°C, on Coscinodiscus granii under laboratory conditions. A decreased infection rate of the parasite was observed at the elevated temperature. Comparative metabolomic analysis using UHPLC-HRMS revealed that temperature and parasitism significantly affect the algal metabolome. Abundances of metabolites related to sulfur metabolism, including cysteinoleic acid and dimethylsulfoniopropionate, as well as molecules linked to fatty acid metabolism, e.g., carnitine, acetylcarnitine, and eicosapentaenoic acid, significantly increase in cells grown at a higher temperature, suggesting the enhanced rate of metabolism of host cells as temperature rises. Our study reveals how temperature-induced metabolic changes can influence host-parasite dynamics in a changing climate.

Megaselia scalaris and Senotainia tricuspis are two parasitoid flies of the honeybee Apis mellifera and are known to infest apiaries of different European and Mediterranean countries. However, their prevalence is still little known and no systematic control of their presence and countermeasures are currently adopted. To achieve a better knowledge about their distribution in apiaries, quantitative PCR (qPCR) based methods for their rapid detection directly in hive matrices were developed in this study. These were applied to samples of adult honeybees and hive debris collected in the summer season in Central Italy and Kosovo. In total 16 samples per type per region were analyzed. Both flies were detected in the two geographical contexts but more frequently in Central Italy. The positive apiaries in Central Italy were re-sampled one year later by capturing viable honeybees and isolating emerging flies after differentiation into adults. These were genotyped by sequencing regions of the mitochondrial cytochrome oxidase subunit I gene COI for M. scalaris and cytochrome B gene cytB for S. tricuspis amplified with specific primers designed in this study. Different genotypes of M. scalaris were detected and these were related to biotypes from distant nations. Some fly isolates were shown to harbor DNA or RNA of honeybee microbial pathogens. Results suggested to implement efficient control against these parasites in apiaries to limit their detrimental effects. The qPCR tests that have been developed can facilitate larger screening studies and early detection.