Search

BACKGROUND: Egg parasitoids are important biological control agents of lepidopteran pests of agricultural crops. Trichogramma evanescens Westwood and T. pintoi Voegele (Hymenoptera: Trichogrammatidae) are egg parasitoids with worldwide importance. The parasitoid selection necessitates comparative assessment of the life table traits and functional response analysis to provide insights into their effectiveness in pest control. In this study, we examined their life table traits including survivorship and reproductivity, and functional response and associated parameters i.e., attack coefficient and handling time. RESULTS: Life table parameters, using age‐stage, two‐sex theory, revealed similar survival and reproductive strategies for both species. For example, the female longevity, oviposition days and fecundity did not differ between both species. Exceptionally, the male longevity of T. evanescens was shorter than that of T. pintoi. The population growth parameters such as gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and mean generation time (T) did not differ between species. The polynomial logistic regression yielded a type III functional response and a non‐linear least square analysis revealed different attack coefficient and similar handling time. However, their parasitism rate differed between the lowest (five eggs) and highest (80 eggs) initial host egg densities such that T. evanescens had a lower parasitism rate at the lowest density and higher parasitism rate at the highest density. CONCLUSION: The similarity in survival strategies and minor differences in host handling of both parasitoids are discussed in terms of relevance to applied biological control applications and evolutionary traits. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: The augmentative release of the parasitoid species Anastatus japonicus Ashmead (Hymenoptera: Eupelmidae) is essential for managing the recent invasion of litchi stink bugs (Tessaratoma papillosa (Drury)) (Hemiptera: Tessaratomidae) in Taiwan. The mass release program in the spring targets this univoltine pest's reproduction cycle. Low-temperature storage for the host eggs and parasitoids is required to maximize the production for the annual release program. This study aimed to enhance the shelf life of Samia cynthia (Lepidoptera: Saturniidae) eggs using the combination of refrigeration and individual quick freezing (IQF) as a storage treatment. Storage of A. japonicus in the IQF-treated S. cynthia eggs was evaluated to determine the optimal production process during the short preparation window before the release. Results: The influences of cold storage and IQF treatment on the host eggs were evaluated for different storage durations. The host quality was determined according to the emergence rate and female ratio of A. japonicus. The study's results demonstrated that the host quality of S. cynthia eggs did not change significantly compared to the control group after 28 d of refrigeration at 7 °C. IQF treatment extended S. cyathia's shelf life to 5 months without significantly affecting the host quality. Applying IQF at different developmental stages of the host eggs affected the parasitism rates of A. japonicus. Significantly higher emergence rates of A. japonicus were recorded in the eggs treated during the initial development (D0 to D2). However, storing parasitoids in the IQF-treated eggs under the current storage condition for one month at 12 °C significantly impacted the parasitoid's emergence rate. Conclusions: The results of this study highlight the potential benefits of the individual quick freezing technique. This technique didn't alter the egg quality of S. cynthia, a crucial factor for the mass production of A. japonicus. The IQF treatment extends the shelf life of the host eggs to 5 months when stored at − 20 °C, a significant improvement compared to the 4-week shelf life without IQF treatment. This technology offers a promising and efficient approach for the mass production of A. japonicus and supports field releases. The treatment allowed for the stockpiling of host eggs during the off-season, which can help expedite the mass production of A. japonicus to fit an eight-week production window. [ABSTRACT FROM AUTHOR]

Colours in nature can be pigmentary, structural or a combination of both. The prevalence, function and nanostructural origin of structural coloration in eggs is largely unknown. Stick and leaf insect eggs display a wide variety of colours, most of which are produced by pigments. The eggs of Myronides glaucus (Phasmida: Lonchodidae; Hennemann, 2021), however, show a clear purple to green iridescence. Here, we use micro‐spectrophotometry, Fourier‐transform infrared reflectance, transmission‐ and scanning electron microscopy, atomic force microscopy, finite‐difference time‐domain optical simulations and experimental approaches to elucidate the mechanism for iridescence in M. glaucus eggshells, which together reveal that iridescence is caused by thin‐film interference by a 200‐ to 450‐nm‐thick outermost layer. These results highlight the diversity of phasmid eggs and the need to study the different mechanisms and functions of structural coloration. [ABSTRACT FROM AUTHOR]

Both the amount and spatial arrangement (configurational heterogeneity) of resources can affect population abundance and community diversity via influence on the growth, survival, reproduction, recruitment and movement of species. However, in most cases, it is difficult to separate the effects of resource amount from arrangement because these two attributes are often naturally correlated. In this study, we examined the configurational heterogeneity of resources (oviposition habitat—emergent rocks, ER) within rivers and decoupled the effects of resource amount from those due to the spatial arrangement on oviposition by eight species of aquatic insects (seven caddisflies and one mayfly). To capture the configurational heterogeneity of resources in 28 sites (riffles) across multiple streams in Australia and Scotland, we calculated fractal dimensions (DB) using the box‐counting technique. We then used simulated riffles to explore how numbers of ER, edginess (the proportion of ER along river margins) and patchiness (clustering of emergent rocks in the middle) separately and together affected the values of DB using asymptotic regression models. Finally, we used multiple regression to test whether the numbers of egg masses laid in natural riffles of each of the eight species were explained by the number of ER, fractal dimension or both. The distributions of ER in natural riffles were scale‐independent, self‐repeating patterns (i.e. they were fractal), and values of DB varied significantly among riffles. Variations in fractal dimensions among simulated riffles were significantly related to the number of ER, edginess and patchiness. However, in natural riffles, only the number of ER and patchiness affected DB. Egg mass abundances were related to the fractal dimensions of ER distributions in riffles in three species and to the number of ER in five species. The fractal dimensions of riffles are unlikely to be driven by large‐scale processes but instead may result from within‐riffle variability that influences rock movement, arrangement and emergence. Increased oviposition by aquatic insects in riffles with greater numbers of ER suggests that these species may be limited by the amount of oviposition resources. Of the species responding to fractal dimension, two species favoured tightly clustered ER whereas the third favoured ER in much looser clusters. It is feasible that aquatic insects can detect ER clusters from the air by responding to changes in the reflectivity of water (albedo) caused by turbulence around ER. That fractals can capture configurational heterogeneity of resources in streams suggests that this technique is useful to test for general ecological patterns across diverse stream systems. Whether configurational heterogeneity influences adults directly or indirectly, these results showed that the amount and arrangement of suitable oviposition habitat plays a role in determining egg mass densities, with potential consequences for larval densities. These patterns may have important community‐level and functional consequences and hence spatial arrangements should be considered when humans manipulate these resources in rivers. [ABSTRACT FROM AUTHOR]

In addition to preventing precocious larval metamorphosis, juvenile hormone (JH), synthesized in corpora allata (CA), is known to stimulate female reproduction of insects. JH titer is extremely low or absent during metamorphosis, but thereafter rapidly increases in the previtellogenic stage and rises to a peak in the vitellogenic phase. However, the mechanisms underlying the biosynthesis of high levels of JH in adults remain unclear. We found in this study that 12 genes involved in JH synthesis pathway were highly expressed in the CA of adult locusts. By transcriptome analysis and quantitative real‐time – polymerase chain reaction validation, a total of 106 evolutionary conserved micro RNAs (miRNAs) and 163 species‐specific miRNAs were identified in locust CA. Dual‐luciferase assay revealed that 17 miRNAs bound to 10 JH synthesis genes (JHSGs) and downregulated their expression. These miRNAs were expressed in low levels during vitellogenic stage, which was oppositive from that of targeting JHSGs. Six miRNAs including miR‐971‐3p, miR‐31a, miR‐9‐5p, miR‐1‐3p, miR‐315, and miR‐282 were selected for function study. Co‐application of agomiRs resulted in significantly decreased levels of targeting JHSGs, accompanied by significantly reduced vitellogenin expression as well as arrested ovarian development. The data suggest that multiple miRNAs expressed synchronously at low levels in the vitellogenic phase, thereby ensuring the high levels of JHSG expression to facilitate JH biosynthesis required for JH‐dependent female reproduction. The findings provide important information for deciphering miRNA—messenger RNA modules for JH biosynthesis as well as JH regulation of insect metamorphosis and reproduction. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) has been included by the World Health Organization in its list of "priority pathogens" because of its widespread prevalence and the severity of the infections it causes. The role of food in infections caused by MRSA is unknown, although strains of this microorganism have been detected in various items for human consumption. In order to gain an overview of any possible role of food in MRSA infections, a review was undertaken of studies published between January 2001 and February 2024 relating to MRSA. These comprised research that focused on fish and shellfish, eggs and egg products, foods of vegetable origin, other foodstuffs (e.g., honey or edible insects), and drinking water. In most of these investigations, no prior enrichment was carried out when isolating strains. Three principal methods were used to confirm the presence of MRSA, namely amplification of the mecA gene by PCR, amplification of the mecA and the mecC genes by PCR, and disc diffusion techniques testing susceptibility to cefoxitin (30 μg) and oxacillin (1 μg). The great diversity of methods used for the determination of MRSA in foods and water makes comparison between these research works difficult. The prevalence of MRSA varied according to the food type considered, ranging between 0.0% and 100% (average 11.7 ± 20.3%) for fish and shellfish samples, between 0.0% and 11.0% (average 1.2 ± 3.5%) for egg and egg products, between 0.0% and 20.8% (average 2.5 ± 6.8%) for foods of vegetable origin, between 0.6% and 29.5% (average 28.2 ± 30.3%) for other foodstuffs, and between 0.0% and 36.7% (average 17.0 ± 14.0%) for drinking water. [ABSTRACT FROM AUTHOR]

The article discusses the transpacific crossings of beetle borer at several sugar transplantations in Hawaii. Topics mentioned include a description of beetle borer's parasitoid called tachinid fly, the history of sugar, the physical and socioecological geographies of the Pacific Ocean, the examination of insects as coconsumers and coproducers, and the birth of the Hawaiian sugarcane.

ABSTRACT Insects have evolved a spectrum of strategies that facilitate survival in the face of adverse environmental conditions and bottom‐up or top‐down pressures. The egg is the first stage in the life cycle of most insects. It is not only immobile but in many insects is the stage that survives unfavourable seasons when food resources are unavailable. Eggs are targeted by oophagous natural enemies and also are subject to abiotic stresses. In response to these diverse stresses, insects have developed various egg protection strategies. Females of many insects lay eggs in clusters and then use their own body resources to cover them to provide protection from harsh environments and biotic attack. Such egg protection strategies have allowed some herbivorous insects to thrive in new environments and become serious invasive pests. Females of many insects protect their eggs in other ways (e.g. laying eggs in concealed places, direct parental care) while others do not provide protection at all. Here, we review various egg protective strategies in insects. Our focus is on adaptive ecological mechanisms and temporal variation as well as the benefits and costs of egg coverings. We highlight several case studies on how these egg protective traits might impede biological control of globally important agricultural and forest pests and propose a framework for incorporating egg protective traits into biological control programs especially for invasive insect pests. [ABSTRACT FROM AUTHOR]

The hemagglutination inhibition (HI) assay is a traditional laboratory procedure for detection and quantitation of serum antibodies of hemagglutinating viruses containing the hemagglutinin (HA) gene. The current study aimed to investigate the novel use of virus like particles (VLP) as an antigen for the HI assay. VLPs were prepared from a strain of H5N1 using a baculovirus expression system. The VLPs were characterized using the hemagglutination test, Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting, and transmission electron microscopy. The comparative HI assay was performed using three different seed antigens: A/chicken/Mexico/232/94 (H5N2), A/chicken/Egypt/18-H/09(H5N1) and A/goose/Guangdong/1/1996(H5N1). The HI assay of serum antibody titrations using homologous antigens to these vaccinal seeds were compared to the VLP's antigens for the same serum. The HI titers were logically relevant to the similarity between VLP antigens and vaccinal seeds, indicating the VLPs behave similarly to the standard HI assay which uses inactivated whole virus as an antigen. VLPs could be considered as an alternative to the HI assay antigen as they show a relatedness between the similarity with vaccinal seed and serum antibodies. Compared to typical entire H5N1 viral antigen prepared in SPF eggs that require proper inactivation to avoid any public health risk, VLPs prepared in tissue culture, plants or insect cells are a safe, inexpensive and scalable alternative to inactivated whole virus antigen. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the phytochemical composition and evaluate the antifungal and insecticidal properties of Rosmarinus officinalis essential oil (EO). GC‐MS was employed to analyze the phytochemical profile of the EO. The antifungal activity of the EO was assessed by calculating growth inhibition rates for Alternaria alternata, Fusarium oxysporum, and Botrytis cinerea. Repellent capacity and toxicity were evaluated through inhalation and contact tests on Callosobruchus maculatus. Molecular docking techniques were utilized to test the insecticidal and antifungal activities of rosemary EO. The analysis revealed a total of sixteen components in R. officinalis EO, with 1,8‐cineole (40.80%) being the major constituent, followed by α‐pinene (26.18%) and camphor (19.53%). Antifungal evaluation demonstrated a significant inhibitory impact on the mycelial growth of the tested fungi, with complete inhibition observed against B. cinerea. In terms of insecticidal capacity, the EO induced complete mortality of C. maculatus adults at a concentration of 1 μL/L air, with an inhalation test LC50 value of 0.62 μL/L air. Concentration‐dependent reductions were observed in the number of both laid eggs and emerged insects, reaching a 99.36% reduction. The EO also exhibited a moderate effectiveness in repelling insects, with an average repellency rate of 50.83%. In silico analysis identified borneol as the most active molecule against insect acetylcholinesterase (PDB: 6ARY) with a Glide score of −7.254 kcal/mol. α‐Caryophyllene showed the highest activity against B. cinerea β‐tubulin (PDB: 3N2G) with a Glide score of −7.025 kcal/mol. These findings suggest that the EO derived from Moroccan Rosmarinus officinalis has potential as an effective natural agent against pathogenic fungi and could serve as a sustainable and environmentally friendly alternative as a bioinsecticide. [ABSTRACT FROM AUTHOR]

Neighbouring plant species can indirectly affect each other's fitness through insect herbivores. For instance, the number of eggs an insect deposits on a focal plant can be influenced by the presence of a neighbouring plant species because of the herbivore's relative host plant preferences. Yet, the relationship between oviposition preferences (measured in no‐choice tests) and the strength and direction of such indirect effects among neighbouring plants remains poorly understood.We performed a lab experiment using bean beetles (Callosobruchus maculatus) and five species of beans to determine if beetles' no‐choice preferences for a neighbouring bean species correlated with the number of eggs laid on a focal species in two‐species environments (diculture).We predicted that as the preference for the neighbouring beans increased compared to the focal host, beetles would lay fewer eggs on the focal bean host.Across all pair‐wise combinations, our prediction was supported: as the relative no‐choice preference of neighbouring beans increased, the number of eggs laid on focal beans decreased. However, this relationship was relatively weak. We also found that beetles tended to lay more eggs in diculture compared to arenas with one bean species.These results provide empirical evidence linking herbivores' no‐choice preferences to the strength of neighbourhood effects and suggest that even within a relatively controlled environment, neighbourhood effects can be weak. Our results also highlight that unexpected changes to the total number of eggs laid by herbivores in mixed‐plant patches relative to monoculture can complicate predictions. [ABSTRACT FROM AUTHOR]

Plants can respond to insect egg deposition by emitting oviposition‐induced plant volatiles (OIPVs) recruiting parasitoids. The recruitment of carnivore insects in response to egg deposition is considered an indirect defence strategy that is widespread in the plant kingdom. In recent years, there has been increasing evidence showing that microbial colonization can influence the strength of plant responses to insect herbivory, yet no information is available on how beneficial microbes modulate indirect defences induced by insect egg deposition.In this work, we evaluated the effects of inoculation with the beneficial soil fungus Trichoderma harzianum strain T22 on a tritrophic system consisting of tomato, the southern green stink bug Nezara viridula and its associated egg parasitoid Trissolcus basalis. We used Y‐tube olfactometer assays to evaluate the behavioural responses of the parasitoids to OIPVs emitted by plants colonized with beneficial soil microbes. We also used gas chromatography coupled with mass spectrometry (GC–MS) to investigate whether and how root inoculation with T. harzianum T22 affects the chemical composition of induced plant volatiles.In olfactometer assays, we found that root inoculation with T. harzianum T22 enhanced the attraction of the egg parasitoid towards tomato plants induced by N. viridula feeding and oviposition activities. In particular, the egg parasitoid preferred OIPVs emitted by tomato plants previously inoculated with T. harzianum T22 over OIPVs emitted by non‐inoculated plants. Furthermore, chemical analysis showed that root inoculation with T. harzianum T22 resulted in changes in the composition of OIPVs, which was consistent with the behavioural observations. Among the compounds that strongly contribute to the chemical differences between OIPVs from non‐inoculated and inoculated plants, chemical analysis identified green leaf volatiles ((Z)‐3‐hepten‐1‐ol, (E,E)‐2,4‐hexadienal), along with terpenoids (terpinen 4‐ol, α‐tujene and δ‐elemene).Taken together our results indicate that beneficial soil microbes enhance indirect plant defences induced by feeding and oviposition, broadening our understanding of plant responses to insect eggs. Our results underscore the importance of taking into account the role of microorganisms to fully comprehend the intricate interactions among plants, herbivore eggs and their associated egg parasitoids. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Cadra cautella (Walker) (Lepidoptera: Pyralidae) is a pest in barn, and its eggs are often utilized as an alternative prey or as hosts for mass production of insect predators and parasitoids. To aid in developing a mass-rearing system for C. castella, the suitability of using an artificial diet based on brown rice flour and whole brown rice was compared using the age-stage, 2-sex life table. Compared with those reared on brown rice, the insects reared on an artificial diet had a shorter preadult period (32.08 vs 37.38 d), higher fecundity (468.14 vs 356.20 eggs/female), greater intrinsic rate of increase (0.1509 vs 0.1145 d−1), and higher net reproductive rate (199.28 vs 103.52 offspring). Small populations were required to rear the moth on an artificial diet to achieve the same daily production of C. cautella. Still, the food expense was only 60.2% of that of C. cautella reared on brown rice. Approximately 99.44% of the eggs in each rearing procedure could be supplied as alternative prey for predators, with the remainder served to maintain the colonies for subsequent batches. Only eggs laid within 6 d would be utilized to ensure the high quality of alternative prey for the mass production of predacious bugs. Additionally, a multifunctional device was designed for moth rearing and egg collection, reducing labor input and minimizing health risks for workers coping with inhaled scales. To encourage the production of natural enemies, a cost-effective diet for maintaining a sustainable colony, and a system for daily egg-harvesting of alternative prey were proposed. [ABSTRACT FROM AUTHOR]

Bombyx mori is a lepidopteran holometabolous insect with distinct developmental stages: egg, larvae, pupae, and adult. The lepidopteran insect undergoes major modifications in the central nervous system (CNS) so as to adapt to the lifestyle of these distinct stages with specific habitats and functions from voraciously feeding larval stages to flying reproductive adults via dormant pupal stages. Such transitions are linked to transcriptional, epigenetic, and translational complexities. Therefore, studying rhythmic gene expression in CNS of various developmental stages and the effects of antagonists on developmental hormones requires a very stable reference gene (RG). To facilitate rhythmic gene expression studies using reverse transcription quantitative polymerase chain reaction (RT-qPCR) in B. mori and the effect of developmental hormone juvenile hormone (JH) and 20-hydroxy ecdysone hormone (20 HE), antagonists Precocene 1 and testosterone, respectively, were used. Eight candidate RGs, namely, Translational initiation factor 3 subunit 4 (TI3S4), Translational initiation factor 3 subunit 5 (TI3S5), Ribosomal protein subunit 7 (RPs7), TATA-binding protein association factor (TAF13), Translational initiation factor 4 A (TI4A), Ribosomal protein (RPL32), Elongation factor 1 (EF1), and Arginine kinase (AK), were assessed in the CNS of B. mori. The postembryonic developmental (PED) stages used were the fifth late larval instar, early pupa, mid pupa, late pupa, and adult. The assessments were done at four different time points, Zeitgeber time (ZT) 0, 6, 12, and 18, to find stability towards 24-h rhythmic expression. RefFinder, geNorm, and Ct value analysis were performed. RefFinder and geNORM studies suggested stability order as TI3S4 > TI3S5 > RPs7, but Ct value evaluation showed stability order as TI3S5 > TI3S4 > RPs7. We therefore demonstrated that TI3S4, TI3S5, and RPs7 can be used as RG in various PED stages in CNS of B. mori (Strain: CB-hybrid, PMÃ--CSR2) towards studies with effects of JH and 20 HE antagonists. [ABSTRACT FROM AUTHOR]

Body size is a characteristic of many animal species that is correlated with many fitness‐related traits. Parasitoids are important biological control agents of pests; larger parasitoids often have greater fitness and enhanced performance. Host size is a major influence on parasitoid size, which has been explored in the important egg parasitoid Anastatus disparis (Hymenoptera: Eupelmidae), a potential biological control agent for several Lepidopteran pests. Here, we found that the body size of A. disparis females increased with increasing host egg size, while host egg size did not significantly affect male size. In addition, both female and male offspring sizes significantly increased with increasing maternal size, and female offspring produced by younger mothers were also larger. Furthermore, the body sizes of both females and males appeared to increase when the total development time from egg to adult eclosion decreased. Male offspring produced by larger females have shorter development times, while female offspring produced by older females have longer development times. Consequently, our results suggested that the effect of maternal status on offspring size may be mediated by influencing development time. In summary, our results indicated that the body size of A. disparis is determined by multiple factors with differing effects on females and males, and our results provide guidance for its effective mass rearing and its performance in the field. [ABSTRACT FROM AUTHOR]

Ascogaster mimetica Viereck is an egg-larval parasitoid that targets Sparganothis sulfureana Clemens, a major cranberry pest in North America. While previous studies have shown that other Ascogaster species respond to cues from their hosts' eggs, it remains unknown whether A. mimetica utilizes these cues to recognize S. sulfureana. We hypothesized that female A. mimetica recognizes S. sulfureana from another cranberry pest, Choristoneura parallela Robinson, based on the presence of surface cues on eggs. To test this, we observed female A. mimetica behavior when exposed to eggs from its host, S. sulfureana ; a nonhost, C. parallela ; and eggs of S. sulfureana that were washed clean with hexane. Additionally, we tracked parasitism rates in each group. Our results revealed that A. mimetica spent 9.5 times longer walking when exposed to C. parallela eggs and 6 times longer when exposed to hexane-washed S. sulfureana eggs compared to unwashed S. sulfureana eggs. Also, A. mimetica spent 3 times longer grooming when exposed to hexane-washed than unwashed S. sulfureana eggs. In contrast, females spent 6 and 18 times longer drumming and probing/ovipositing on unwashed S. sulfureana eggs than on C. parallela eggs and 5 times longer probing/ovipositing on unwashed S. sulfureana eggs than on hexane-washed S. sulfureana eggs. Higher parasitism rates were observed from unwashed S. sulfureana eggs compared to those from C. parallela eggs and hexane-washed S. sulfureana eggs. Our findings suggest that the presence of egg surface cues, like scales, of S. sulfureana likely plays a crucial role in host acceptance and parasitism success for A. mimeti ca. [ABSTRACT FROM AUTHOR]

Seventeen-year periodical cicadas represent an extreme life history, with individuals spending 17 years as juveniles and less than 45 days as adults. The implications of this life history on investment in immunity are unknown. Using monofilament implants, we examined sex differences in melanization and encapsulation-based immunity in Brood X Magicicada septendecim and M. cassini periodical cicadas. In many insects, females devote more effort to immunity than males which allows females additional time to lay eggs before death. In 17-year cicadas, the functional difference in lifespan between males and females is trivial as compared to their total lifespan. However, we found that in both species, adult females had better immunity (encapsulation response) than males. In both species, male immunity (melanization and encapsulation) declined as they aged, as did female encapsulation. However, female immunity (melanization) either did not decline or improved with age. We conclude that although male immunosenescence resembles that of shorter-lived insects, for females, melanization-based immunity is preserved as they age, potentially due to their unique life history. We also examined whether being housed in mixed-sex versus single-sex enclosures affected immunity but did not find an effect of reproductive opportunity on either melanization or encapsulation in males or females of either species. This is the first study to assay melanization or encapsulation in a cicada, so our results provide a first look at sex- and age-based immunity in this group. [ABSTRACT FROM AUTHOR]

The forage Urochloa ruziziensis ((R. Germ. and C.M. Evrard) Crins (synonym Brachiaria ruziziensis) (Poales: Poaceae)) has great potential to be adopted as pasture. However, this forage is susceptible to spittlebugs, the main insect pest of pastures in Brazil. Thus, the objective of this study was to select genotypes of U. ruziziensis resistant to Deois schach (Fabricius) and Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) through 16 cycles of recurrent selection. The resistance of 13,114 U. ruziziensis plants to spittlebugs was evaluated in experiments conducted between 2008 and 2023. Each plant was infested with six eggs of the insect pest at stage S4 and kept in a greenhouse for up to 40 days. After this period, surviving nymphs from the second to fifth instars were counted. The original population of U. ruziziensis (POP01-2008) presented a nymphal survival rate of 63%, while for the improved population (POP36-2023) the average nymphal survival rate was 32.8%. The estimated total genetic gain was 15%, and the annual genetic gain was 1%. After 16 selection cycles, in POP36-2023, approximately 63% of the genotypes (716 plants), had nymphal survival rates equal to or less than 33% and were considered resistant to D. schach and M. spectabilis nymphs. [ABSTRACT FROM AUTHOR]

Species‐rich semi‐natural grasslands have been lost during the last century due to agricultural intensification. This has had large negative consequences for many specialised species, including grassland butterflies. To prevent further loss, management regimes in the remaining grasslands must maintain habitat quality over time, and we therefore need to understand the habitat preferences of specialised species and how different management regimes affect their survival.We studied the egg‐laying preferences of the threatened marsh fritillary butterfly in relation to host plant properties, microclimate and management (grazing) on Gotland, Sweden. Moreover, we followed the survival of eggs and larvae from 27 egg batches during a period of 8 months (from June 2020 to March 2021) in grazed and ungrazed areas.We found 92 egg batches in total and the average number of eggs was 184.5. Egg‐laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south‐facing edges). The 27 egg batches that were followed over time had on average 203 eggs in June. Roughly 28% of the eggs developed into larvae, and about 17% of these survived over the entire study period, resulting in an overall 4.7% survival. Egg survival was higher in ungrazed habitats compared with grazed; in March (post‐hibernation), there were almost nine times more eggs in ungrazed habitats.This study highlights the complex habitat ecology of specialised butterflies and underscores the detrimental impact of intense grazing, advocating for rotational grazing or mowing regimes. [ABSTRACT FROM AUTHOR]

Insect eggs, once oviposited, defend against abiotic and biotic factors using thickness, secretions, or other defenses. The eggs of most insect species are attacked by parasitoid wasps, which are often their most significant mortality factors. The present study is the first investigation of microfilaments as defense from parasitoids. Specifically, the effect of the corn leafhopper Dalbulus maidis DeLong (Hemiptera: Cicadellidae) egg microfilaments against parasitism by Anagrus virlaiTriapitsyn (Hymenoptera: Mymaridae) and Paracentrobia subflava (Girault) (Hymenoptera:Trichogrammatidae) was evaluated. Field and laboratory experiments were conducted to evaluate several biological traits related to parasitism in D. maidis eggs with and without microfilaments. An initial field experiment found no difference in parasitism by A. virlai and P. subflava of eggs with vs. without microfilaments after 5 days of exposure of healthy D. maidis eggs to parasitism. A second field experiment then looked at exposure for 1 day, and this treatment found greater parasitism of healthy D. maidis eggs by each parasitoid species in eggs without microfilaments vs. in eggs with microfilaments. Laboratory experiments conducted separately for A. virlai and P. subflava parasitism after 1 day of exposure to healthy D. maidis eggs confirmed a higher percentage of parasitoid emergence in the eggs without microfilaments (both young and mature eggs) vs. mature eggs with microfilaments. These results suggest that eggs without microfilaments are more parasitized than eggs with microfilaments during a 1-day exposure, but that this difference disappears as egg microfilaments regrow over a 5-day period. Graphical Abstract [ABSTRACT FROM AUTHOR]

Trissolcuss grandis Thomson, is an important egg parasitoid of Eurygaster integriceps Puton that can control its population in wheat and barley fields. Despite valuable results from previous studies, the thermal development of T. grandis over a wide range of temperatures had not been elucidated completely. This study was conducted to evaluate the thermal effect on the development of T. grandis using Sunn pest eggs as hosts in a wide range of temperatures (12.5 to 40 ±0.5ºC, 65 ± 5% RH., and a photoperiod of 16L:8D h) in the laboratory condition. The development times of the immature stage (Egg-Adult) of T. grandis decreased with increasing temperatures up to 35 ºC for both sexes. Patterns of temperature-dependent development times of the immature stage of females and males (i.e. emergence of females and males of T. grandis adults) were modeled and simulated with linear and nonlinear regression analyses. The estimated low-threshold temperatures (Tb) were 10.61 and 10.62 ºC for females and males, respectively. Thermal constants (k) of the immature stage of females and males were 179.85 and 161.03 degree-days (DD), respectively. Stage transition models for females and males adults of T. grandis were constructed using two basic components of nonlinear development rate (modified Sharpe & DeMichele model function) and distribution models (two-parameter Weibull function) to simulate the proportion of individuals shifted from egg to adult. These models will be useful in building a T. grandis population model that will describe its seasonal occurrence pattern and population dynamics under various wheat and barley fields and optimize environmental conditions in mass rearing. [ABSTRACT FROM AUTHOR]

This article, published in Integrative Zoology, explores the temporal transcriptomic changes in willow leaves after being oviposited by Plagiodera versicolora, a globally distributed pest. The study used RNA-Seq and weighted gene co-expression network analysis (WGCNA) to analyze gene expression patterns and identify key candidate genes related to these changes. The results showed that insect egg deposition induced significant differential expression of genes associated with metabolic responses and plant stress. The study provides new insights into the interactions between insects and plants and may contribute to pest control strategies. [Extracted from the article]

Female fecundity is dependent on age and mated status. Young female insects accumulate considerable fat stores to fuel energetically expensive ovary development and egg production. Consequently, younger females are expected to have more stored fat than older females while the latter should have larger eggloads than the former. Mating is expected to increase fecundity because male ejaculates contain fecundity-enhancing substances that stimulate egg development, ovulation and oviposition. We experimentally tested the effect of female age (young versus old) and mated status (virgin versus mated) on fat and eggloads in female Gryllus firmus field crickets (Orthoptera: Gryllidae), in addition to testing the prediction that young or mated females have higher resting metabolic rates (RMR) than old or virgin females because the former should be significantly more engaged in the energetically expensive activity of egg production than the latter. As predicted, we found that young females had more fat and fewer eggs than old females and that fat loads negatively correlated with fecundity across all females. Young females also exhibited higher RMR, as expected if egg production is energetically costly. Contrary to expectation, however, mated status had little effect on fat load, egg production or RMR. That mating had little effect on total egg production (i.e. stored and oviposited eggs) challenges the hypothesis that male fecundity-enhancing substances in the ejaculate stimulate egg production. Our experiment also permitted us to examine the validity of two popular indices of body condition, the scaled mass index (SMI) and residual body mass (R i). Neither index accurately represented the true treatment effects of age and mated status on fat load; however, the SMI reflected true fat content in young, but not old, females. • We tested effects of age and mated status on fat and eggloads in female Gryllus firmus. • Young females had more fat and fewer eggs than old females. • Fat loads were negatively correlated with fecundity across all females. • Young females had a higher resting metabolic rate (RMR) than old females. • Mated status had little effect on fat load, egg production or RMR. [ABSTRACT FROM AUTHOR]

The sex of Lepidoptera species can typically be identified at the pupal or adult stage by their morphological characteristics. However, for most species, no obvious sex‐specific traits can be used at the larval or embryonic stage. The growing interest in studying sex determination and differentiation, along with the potential application of research findings in genetic regulation techniques, is promoting the advancement of new sexing methods at early developmental stages. In this study, the sex of individual eggs and larvae was successfully identified by means of W chromosome molecular markers, which were identified through analysing the previously published W chromosome sequence data of Spodoptera frugiperda (Lepidoptera: Noctuidae). Additionally, we present methods to extract DNA and RNA from individual eggs and larval hemolymph. These techniques provide a simple and dependable method to identify sex at pre‐pupal stages. This approach could potentially be extended to other Lepidoptera species of which the W chromosome information is available. [ABSTRACT FROM AUTHOR]

The success of an organism depends on the molecular and ecological adaptations that promote its beneficial fitness. Parasitoids are valuable biocontrol agents for successfully managing agricultural pests, and they have evolved diversified strategies to adapt to both the physiological condition of hosts and the competition of other parasitoids. Here, we deconstructed the parasitic strategies in a highly successful parasitoid, Trichopria drosophilae, which parasitizes a broad range of Drosophila hosts, including the globally invasive species D. suzukii. We found that T. drosophilae had developed specialized venom proteins that arrest host development to obtain more nutrients via secreting tissue inhibitors of metalloproteinases (TIMPs), as well as a unique type of cell—teratocytes—that digest host tissues for feeding by releasing trypsin proteins. In addition to the molecular adaptations that optimize nutritional uptake, this pupal parasitoid has evolved ecologically adaptive strategies including the conditional tolerance of intraspecific competition to enhance parasitic success in older hosts and the obligate avoidance of interspecific competition with larval parasitoids. Our study not only demystifies how parasitoids weaponize themselves to colonize formidable hosts but also provided empirical evidence of the intricate coordination between the molecular and ecological adaptations that drive evolutionary success. [ABSTRACT FROM AUTHOR]

In most ectotherms, several life‐history traits, including body size, respond to environmental conditions through the temperature–size rule (TSR). The mechanisms underlying the TSR are still being debated, but studying idiobiont insect parasitoids, which develop with a fixed amount of resources, may shed light on this relationship. In this study, we conducted experiments to determine how the developmental temperature affects various characteristics of male and female Trichogramma euproctidis (Girault) (Hymenoptera: Trichogrammatidae), an idiobiont egg parasitoid of Lepidoptera. The study tested various hypotheses, including the cellular or oxygen diffusion hypotheses and the resource acquisition hypothesis, to understand whether T. euproctidis follows the TSR. The developmental time of both male and female T. euproctidis decreased with increasing temperature. Both males and females displayed a unimodal distribution for size, dry mass, and lipid content, with individuals at lower and higher temperatures being smaller, weighing less, and containing fewer lipids. Female lifetime fecundity increased from 13 to 24 °C and then decreased at 31 °C. Additionally, the number and size of gametes in male and female T. euproctidis displayed a unimodal distribution with increasing temperature. Trichogramma euproctidis deviates from the TSR as it follows a non‐linear reaction norm with an optimal developmental temperature. This result supports the hypothesis that for species following TSR and having unlimited access to food resources, the resource acquisition hypothesis is a significant mechanism explaining the TSR. With climate change affecting temperature, understanding the TSR is crucial, and research on insect parasitoids may help reveal how the interplay between environmental temperature and resource allocation affects the TSR in natural populations. [ABSTRACT FROM AUTHOR]

The rice stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae), is a key rice pest, causing major yield loss in Asia. Trichogramma japonicum Ashmead (egg parasitoid) and Beauveria bassiana Balsamo Vuillemin (entomopathogenic fungi) are two important organisms used in sequence or integrated for C. suppressalis management. However, few information is available on potential antagonism between the two biocontrol agents. Under laboratory conditions, we assessed whether the presence of B. bassiana had an impact on the oviposition preference of T. japonicum for C. suppressalis eggs. We characterized parasitic behavior of T. japonicum exposed or not to B. bassiana on C. suppressalis eggs (varying in age) by carrying out observation experiments and using a Y-tube olfactometer. We also evaluated the response of T. japonicum to B. bassiana-affected vs. -unaffected C. suppressalis eggs. Olfactometer tests showed that T. japonicum-vectored B. bassiana and/or C. suppressalis eggs immersed in B. bassiana did not have major effects on choices made by the parasitoid. T. japonicum attacked C. suppressalis eggs of 0-d, 2-d and 4-d old and had preference to fresh host eggs (0-d). However, the contaminated T. japonicum were not able to distinguish between eggs of 0-d old and 4-d old in contrast with the uncontaminated parasitoids. A reduction in insect locomotion (no-response number) of T. japonicum contaminated by B. bassiana preferring to 4-d-old host eggs was found, which was compared to the no-response number of uncontaminated T. japonicum preferring to 0-d-old host eggs. The parasitic behavior of host searching time, checking time, drilling and oviposition time and the parasitism rate (in 24 h) did not differ between the fresh eggs immersed with B. bassiana and control (eggs without B. bassiana). On the other hand, searching and checking times were slightly higher when parasitoids were contaminated by B. bassiana (drilling and oviposition times as well as the parasitism rate in 24 h were not impacted). Therefore, T. japonicum may be used together with B. bassiana in integrated program targeting C. suppressalis. [ABSTRACT FROM AUTHOR]

Simple Summary: Currently, the optimization of mass rearing conditions for insects is a matter of highly applied and fundamental relevance since insects can be used as a source of protein in feed and feed supplements for farm animals as well as a source of antibacterial compounds for drug development and various insect research activities in laboratory conditions. The quantity and quality of the consumed feed has an effect on insect growth rate, duration of development, body weight, ability to spread, and survival, as well as on the mating success rate and total egg production of females. Suboptimal nutrition, growth, and development can affect beetle viability. We developed an artificial fungi-based diet for rearing an insect group adapted to life in wood and using it as one of their food sources and tested the effect of this diet on various parameters of the insects' development and their immunity. Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) was chosen as a model species (representative of this group of insects). Based on the parameters of development at all stages of Z. atratus and screening of hemolymph antibacterial activity of their larvae, we showed that the cultivation method we developed shortens the development time of beetles and strengthens their immunity. The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is possible to optimize beetle rearing in laboratory conditions. In this study, an artificial fungi-based diet (FD) was developed for the cultivation of the darkling beetle Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) in laboratory conditions as a model object for studying the biology of saproxylophagous beetles. To assess the influence of the diet, a number of physiological parameters were measured, including development time, body size, and weight of all stages of the beetle's life cycle, as well as its immune status. The immune status of Z. atratus was assessed on the basis of larval hemolymph antibacterial activity against six different bacterial strains assessed using disk-diffusion and photometric tests. Our findings show that the FD reduces development time and boosts the immune status as compared to beetles reared on a standard diet (SD). Samples from FD-reared larvae had pronounced antibacterial activity as compared to samples from SD-reared larvae. This work is of fundamental importance for understanding the correlations between nutrition and development of saproxylic Coleoptera and is the first report on immune status regulation in this group of insects. [ABSTRACT FROM AUTHOR]

Simple Summary: Promoting cage-free eggs supports a housing system which may benefit the lives of egg-laying hens. China is the world's largest producer and consumer of eggs, and most of these eggs are produced in caged systems. Our aim was to understand the promotion strategies of companies supplying cage-free eggs in China, through examining 10 companies selling these products to business and consumer buyers. We found that the companies mainly promoted their eggs through considerations of price (for example, by engaging buyers who would pay more), attributes of the egg which buyers can sense (for example, accommodating buyers' preferences for better taste and specific shell colors), and improving buyers' understanding of and trust in non-sensory credence attributes (for example, through communicating to buyers about cage-free production and using trusted certifications). Our study describes strategies of cage-free egg promotion that may also help inform promotion of other products with the potential to improve animal welfare. Successful promotion of cage-free eggs supports a housing system offering potential for improved hen welfare. As the world's largest egg producer and consumer, China offers much potential for welfare improvements. We examined 10 Chinese companies supplying cage-free eggs (four using indoor systems, six with outdoor access) to understand their strategies to promote cage-free eggs to businesses and consumers. We purposively sampled 12 employees from these companies familiar with production or sales. We conducted two–three semi-structured interviews per participant, collected public online documents (including online shops and social media content), and recorded field notes. We analyzed the data using template analysis to generate key results. Participants reported buyers being unfamiliar with 'animal welfare' and 'cage-free', but familiar with concepts associated with 'free-range'. Participants considered three attributes when promoting cage-free eggs: price (engaging buyers who were willing to pay more), experiential attributes (e.g., taste, accommodating buyer preferences), and non-sensory credence attributes (e.g., cage-free production, improving buyers' understanding and trust). Our results are not generalizable, though they may be transferable to similar contexts. Understanding how companies promoted cage-free eggs to buyers may help inform promotion of other animal products with welfare attributes. Simultaneous efforts are needed to ensure actual welfare improvements on farms. [ABSTRACT FROM AUTHOR]

Utilizing parasitoids for augmentative biological control frequently depends on the physiological state of the parasitoids and the pest population density at the time of release. Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) is commonly used as an egg parasitoid for biological insect pest control via augmentation and field release. A crucial component of mass production programmes is the host's nutritional compatibility. So, the investigations were carried out to study the effect of diet composition of Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) on developmental and reproductive parameters of Trichogramma chilonis Ishii. The T. chilonis was reared on Corcyra cephalonica fed on different diets (D1-D7) in the laboratory at 25°C±1°C with 75±5% RH. Based on pooled data of two generations T. chilonis had shown significantly highest parasitization of 85.80%, adult emergence percentage 75.00% and sex-ratio 1.62:1 on rice moth eggs obtained from Maize (48.5%) + Sorghum (48.5%) + Groundnut (3%) diet (D5). Trichogramma adult's emergence was observed earlier (3.10 days) on the host's eggs reared on the Bajra (100%) diet (D1). In case of adult longevity, the maximum longevity of 7.70 days was recorded on the host's egg obtained from the D5 diet over the others. These findings may help to improve the developmental and reproductive performance of T. chilonis and an optimized D5 diet may be useful for mass rearing of this egg parasitoid. [ABSTRACT FROM AUTHOR]

Background: Efficacy of parasitic wasps from the genus Trichogramma to attack the eggs of numerous important pests in various agricultural crops makes them one of the most prevalent biocontrol agents. In Trichogramma, the pre-pupal stage can survive during the cold season in a dormant state (diapause or quiescence). The optimal conditions for the induction of this pause of development during mass rearing to store the parasitoid for a long time in good quality depend on the species. In the present study, four factors [the incubation periods (24 and 48 h), diapause induction temperatures (9 and 11 °C), durations of the diapause induction (from 0 to 6 weeks), and the periods of storage (from 0 to 6 months)], were experimented to force Trichogramma evanescens Westwood, reared on Sitotroga cerealella, to enter diapause or quiescence and estimating their impacts on the efficacy of stored parasitoid. Results: Results confirmed that the life parameters of T. evanescens as the percentage of adult emergence, female percentage, rates of wing deformation of emerged adults, and fecundity of emerged females were significantly affected by all experimented factors. The pre-storage treatments made it possible to store the parasitoid for at least 2 months at 3 °C, with no much changes in their fitness, the emergence rate of adults reached more than 80%, and the egg-laying efficacy of females reached more than 42 eggs per emerged female, when diapause induction treatments were applied for 5 weeks at 11 °C after 24 h of incubation. Furthermore, there is the possibility of storage for 6 months with an acceptable level of parasitoid's quality, when diapause induction treatments were applied for 5 weeks at 9 °C after 24 h of incubation, the emergence rate reached 70%, and the number of eggs per female was 52 eggs, while no emergence of adult insects was recorded after 3 months of cold storage without diapause induction treatments. Conclusion: Two storage programs were reached for T. evanescens (depending on the adult emergence rate and fecundity of emerged females). There is a long-term storage (6 months), when diapause was induced at a low temperature (9 °C) after 24 h of incubation. Short-term storage (from 2 to 4 months), when quiescence was induced under a higher temperature of 11 °C after both 24 and 48 h of incubation. [ABSTRACT FROM AUTHOR]

Activation of immune cells requires the remodeling of cell metabolism in order to support immune function. We study these metabolic changes through the infection of Drosophila larvae by parasitoid wasp. The parasitoid egg is neutralized by differentiating lamellocytes, which encapsulate the egg. A melanization cascade is initiated, producing toxic molecules to destroy the egg while the capsule also protects the host from the toxic reaction. We combined transcriptomics and metabolomics, including 13C-labeled glucose and trehalose tracing, as well as genetic manipulation of sugar metabolism to study changes in metabolism, specifically in Drosophila hemocytes. We found that hemocytes increase the expression of several carbohydrate transporters and accordingly uptake more sugar during infection. These carbohydrates are metabolized by increased glycolysis, associated with lactate production, and cyclic pentose phosphate pathway (PPP), in which glucose-6-phosphate is re-oxidized to maximize NADPH yield. Oxidative PPP is required for lamellocyte differentiation and resistance, as is systemic trehalose metabolism. In addition, fully differentiated lamellocytes use a cytoplasmic form of trehalase to cleave trehalose to glucose and fuel cyclic PPP. Intracellular trehalose metabolism is not required for lamellocyte differentiation, but its down-regulation elevates levels of reactive oxygen species, associated with increased resistance and reduced fitness. Our results suggest that sugar metabolism, and specifically cyclic PPP, within immune cells is important not only to fight infection but also to protect the host from its own immune response and for ensuring fitness of the survivor. Shifts in intracellular metabolism underlie the activation of immune cells and influence an organism's response to pathogens. This study characterizes the metabolic changes underlying immune cell activation in infected Drosophila larvae, showing that increases in glucose and trehalose uptake, and flux through the cyclic pentose phosphate pathway, are important for both effective immune responses and host protection. [ABSTRACT FROM AUTHOR]

Objective: The potential of aqueous extract of Christ's thorn jujube (Ziziphus spina-christi) leaves (SLAE) to reduce the negative impacts of heat stress on production performance and physiological traits was investigated in dual-purpose layers under subtropical farming. Methods: A total of 200, 25-week-old laying hens (Inshas strain) were randomly assigned to four dietary treatments including SLAE at 0, 2.5, 5.0, and 7.5 mL/kg, respectively. The average temperature-humidity index value was 26.69 during the experimental period. The SLAE contained saponin (0.045%), total flavonoid content of 17.9 mg of quercetin equivalent/100 g and overall antioxidant capacity concentration of 17.9 mg of ascorbic acid equivalent/100 g. Results: The maximum final body weight (BW), BW gain, egg weight, number, and mass occurred at the level of SLAE7.5 inclusion. The egg quality was significantly higher in SLAE groups than in control, and overall, SLAE7.5 had the most favorable influence at 28 and 32 weeks. Liver and kidney function, as well as lipids profile, improved significantly by SLAE inclusion; the lowest concentrations of these parameters were in SLAE7.5 hens. Treatment with SLAE7.5 increased total antioxidant capacity and endogenous antioxidant enzymes compared to control, whereas no effect on superoxide dismutase was noticed. Conclusion: The addition of SLAE at 7.5 mL/kg diet improved egg laying performance and quality, metabolic profiles, and antioxidant status during hyperthermia conditions. [ABSTRACT FROM AUTHOR]

Thousands of endoparasitoid wasp species in the families Braconidae and Ichneumonidae harbor "domesticated endogenous viruses" (DEVs) in their genomes. This study focuses on ichneumonid DEVs, named ichnoviruses (IVs). Large quantities of DNA-containing IV virions are produced in ovary calyx cells during the pupal and adult stages of female wasps. Females parasitize host insects by injecting eggs and virions into the body cavity. After injection, virions rapidly infect host cells which is followed by expression of IV genes that promote the successful development of wasp offspring. IV genomes consist of two components: proviral segment loci that serve as templates for circular dsDNAs that are packaged into capsids, and genes from an ancestral virus that produce virions. In this study, we generated a chromosome-scale genome assembly for Hyposotor didymator that harbors H. didymator ichnovirus (HdIV). We identified a total of 67 HdIV loci that are amplified in calyx cells during the wasp pupal stage. We then focused on an HdIV gene, U16, which is transcribed in calyx cells during the initial stages of replication. Sequence analysis indicated that U16 contains a conserved domain in primases from select other viruses. Knockdown of U16 by RNA interference inhibited virion morphogenesis in calyx cells. Genome-wide analysis indicated U16 knockdown also inhibited amplification of HdIV loci in calyx cells. Altogether, our results identified several previously unknown HdIV loci, demonstrated that all HdIV loci are amplified in calyx cells during the pupal stage, and showed that U16 is required for amplification and virion morphogenesis. Author summary: Parasitoid "domesticated endogenous viruses" (DEVs) provide a fascinating example of eukaryotes acquiring new functions through integration of a viral genome. DEVs consist of multiple loci in the genomes of wasps. Upon activation, these elements collectively orchestrate the production of virions or virus-like particles that are crucial for successful parasitism of host insects. Despite the significance of DEVs for parasitoid biology, the mechanisms regulating key steps in virion morphogenesis are largely unknown. In this study, we focused on the ichneumonid parasitoid Hyposoter didymator, which harbors an ichnovirus consisting of 67 proviral loci. Our findings reveal that all proviral loci are simultaneously amplified in ovary calyx cells of female wasps during the pupal stage suggesting the hijacking of cellular replication complexes by viral proteins. We functionally studied the ichnovirus gene U16, which encodes a protein with a weakly conserved primase C-terminal domain. Silencing U16 inhibited viral DNA amplification and virion production, underscoring the key role of this gene for ichnovirus replication. Our study provides evidence that many genes involved in viral DNA replication have been conserved during the domestication of ichnoviruses. [ABSTRACT FROM AUTHOR]

Tetrastichus howardi (Olliff), a pupal endoparasitoid of the major agricultural pest Spodoptera frugiperda (J.E. Smith). Laboratory studies were conducted to determine the effect of the temperature and supplementary food on the development and reproduction of this parasitoid on S. frugiperda pupae. The results revealed that T. howardi could complete the life cycle under all five tested temperatures (18, 22, 26, 30 and 34 °C), with the most extended longevity (female: 42.83 days; male: 24.37 days) and the most prolonged developmental duration (egg-adult) (52.33 days) at 18 °C. Parasitoids that were kept at 26 °C had the greatest parasitism rate (72.67%) and the highest net reproductive rate R0 (56.35), and those maintained at 34 °C had the highest emergence rate (92.03%), the greatest number of emerged progeny (58.40) and the highest intrinsic rate of increase rm (0.310 d−1). Feeding on honey, glucose, and sucrose significantly increased the adult longevity and the progeny production of T. howardi but showed no significant effects on parasitism rate, emergence rate, the developmental duration of progeny, or sex ratio. Parasitoids that fed on glucose lived the longest (21.23 days), and the highest emerged offspring occurred when honey is provided (57.77). These results are instructive for the mass-rearing of T. howardi and field control of S. frugiperda. [ABSTRACT FROM AUTHOR]

Knowledge of plant recognition of insects is largely limited to a few resistance (R) genes against sap‐sucking insects. Hypersensitive response (HR) characterizes monogenic plant traits relying on R genes in several pathosystems. HR‐like cell death can be triggered by eggs of cabbage white butterflies (Pieris spp.), pests of cabbage crops (Brassica spp.), reducing egg survival and representing an effective plant resistance trait before feeding damage occurs. Here, we performed genetic mapping of HR‐like cell death induced by Pieris brassicae eggs in the black mustard Brassica nigra (B. nigra). We show that HR‐like cell death segregates as a Mendelian trait and identified a single dominant locus on chromosome B3, named PEK (Pieris egg‐ killing). Eleven genes are located in an approximately 50 kb region, including a cluster of genes encoding intracellular TIR‐NBS‐LRR (TNL) receptor proteins. The PEK locus is highly polymorphic between the parental accessions of our mapping populations and among B. nigra reference genomes. Our study is the first one to identify a single locus potentially involved in HR‐like cell death induced by insect eggs in B. nigra. Further fine‐mapping, comparative genomics and validation of the PEK locus will shed light on the role of these TNL receptors in egg‐killing HR. Summary statement: Hypersensitive response induced by cabbage white butterfly eggs in Brassica spp. reduces survival and represents an effective plant resistance trait. For the first time, a single dominant locus was identified in the wild crucifer Brassica nigra, which contains a cluster of genes encoding intracellular TIR‐NBS‐LRR (TNLs) receptors. [ABSTRACT FROM AUTHOR]

The use of egg parasitoids in the biological control of insect pests is a promising technique in integrated pest management. However, there is little information on the effects of parasitoid female age and host egg age on parasitization rates specifically on the behaviour of the egg parasitoids such as Trichogramma pretiosum Riley and Telenomus remus Nixon which can have substantial effects on parasitism towards insect pest eggs. Thus, this communication evaluated the relationships between the age of the parasitoid and host egg on the parasitism of Spodoptera frugiperda eggs by T. pretiosum and T. remus in three independent bioassays. In the first and second bioassay, two egg parasitoids (T. pretiosum and T. remus) females were grouped by age in days (ranging from 1–6 and 1–10 days old for T. pretiosum and T. remus, respectively) and were offered 100 eggs of S. frugiperda per treatment for 24 h separately. In the third bioassay, 100 eggs of S. frugiperda of different ages (24, 48 and 72 h old) were offered separately to T. pretiosum and T. remus females for 24 h. The variables such as the number of eggs parasitized, parasitoid emergence (%) and female progeny were evaluated. The results indicated that as the age of the T. pretiosum increases, per cent parasitism and adult emergence decreases but age of T. remus females did not affect the number of S. frugiperda eggs parasitized or the emergence of the progeny. However, the sex ratio was more male-biased in the progeny of 1- and 2-day-old females compared to older wasps in the case of T. remus. In the third bioassay, the highest parasitism was observed in 24- and 48-h-old eggs and the per cent emergence decreased with increasing female age. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effect of supplementing Hermetia illucens larval meal in pheasant diets on selected hatchability parameters and physicochemical properties of eggs. A total of 72 pheasants (63 females and 9 males) were randomly allocated to three groups: BSFL0, a basal diet without H. illucens, and BSFL10 and BSFL20 diets, with 100 and 200 g/kg H. illucens larval meal, respectively. The evaluation of selected egg production indices was based on 1200 properly developed eggs. The BSFL20 group exhibited the highest number of eggs and a reduced percentage of culled eggs compared to the control treatment. The lowest albumen height was determined in BSFL0, and the highest in BSFL20. In addition, the highest Haugh index values were also recorded for the BSFL20 group. Tendencies towards improved survival of chicks were observed up to day 7 and day 14 after hatching, connecting with the incrementing BSFL dose. Egg yolk dry matter and crude protein levels were increased in the BSFL20 group, accompanied by tendencies towards elevated crude ash and reduced cholesterol levels. A significant increase in C12:0 and C14:0 fatty acids in both experimental groups, and a decrease in C18:0 fatty acid levels in the BSFL20 group were observed. A reduction in C16:1 and monounsaturated fatty acid levels was noted in the experimental groups. The atherogenicity index was higher in the BSFL20 group, while the n-6/n-3 ratio was lower compared to the control. In conclusion, H. illucens can be implemented in pheasant diets with beneficial effects on the number of eggs and positive trends for selected survival indices. Furthermore, H. illucens full-fat meal positively modified the chemical composition of the eggs. [ABSTRACT FROM AUTHOR]

Functional response describes the number of hosts attacked by a parasitoid in relation to host densities and plays an important role by connecting behavioral-level processes with community-level processes. Most functional response studies were carried out using simple experimental designs where the insects were confined to a plain and small arena with different host densities during a fixed period of time. With these designs, other factors that might affect the functional response of parasitoids were not analyzed, such as fecundity, age, and experience. We proposed a series of latent-variables Markovian models that comprised an integrated approach of functional response and egg production models to estimate the realized lifetime reproductive success of parasitoids. As a case study, we used the parasitoids Anagyrus cachamai and A. lapachosus (Hymenoptera: Encyrtidae), two candidate agents for neoclassical biocontrol of the Puerto Rican cactus pest mealybug, Hypogeococcus sp. (Hemiptera: Pseudococcidae). The tested species were assessed according to their physiology and prior experience. We estimated the number of mature eggs after emergence, egg production on the first day, egg production rate, the proportion of eggs resorbed, egg resorption threshold, and egg storage capacity. Anagyrus cachamai and A. lapachosus both presented a type III functional response. However, the two parasitoids behaved differently; for A. cachamai, the number of parasitized hosts decreased with female age and depended on the number of mature eggs that were available for oviposition, whereas A. lapachosus host parasitism increased with female age and was modulated by its daily egg load and previous experience. The methodology presented may have large applicability in pest control, invasive species management, and conservation biology, as it has the potential to increase our understanding of the reproductive biology of a wide variety of species, ultimately leading to improved management strategies. [ABSTRACT FROM AUTHOR]

The Emma field cricket, Teleogryllus emma (Ohmachi & Matsuura), distributed between 43°N and 30°N in the Japanese archipelago, is univoltine and overwinters in the egg stage. Its eggs hatch on the slope of the Oishi Dam (38.03°N, 139.57°E, 160–170 m a.s.l.) in late June, adults begin emerging from late August, and oviposition lasts until early October. Oviposition is limited to the period when the water level of the Oishi Dam is low. The period from egg hatching to adult emergence is approximately 1 month shorter than that of the T. emma population on the Arakawa riverside (38.09°N, 139.57°E, 29 m a.s.l.), which is approximately only 7 km from the Oishi Dam. The egg and body sizes of T. emma on the slope of the Oishi Dam were smaller than those of T. emma on the Arakawa riverside, and the egg and nymphal periods were shorter; these variations were inherited by the next generation of T. emma. The egg period, nymphal period and head width of T. emma on the dam slope correspond to those of the populations near 40°N. Several traits of the T. emma population on the dam slope were naturally selected by adapting to the isolated environment, resulting in the genetic variations. However, their variations were small and the period after isolation is short, suggesting that it is in the early stages of speciation. [ABSTRACT FROM AUTHOR]

We studied the effects of varying levels of nitrogen (N), phosphorus (P), and nitrogen and phosphorus mixture (NP) enrichment on the hatching of resting eggs to determine whether nutrient enrichment levels affect the emergence of zooplankton from resting eggs. We treated resting eggs with six different nutrient concentrations and returned them to the in situ water environment to simulate the restoration of a favourable environment after eutrophication. Low nutrient concentrations had a lesser impact on egg hatching compared with high concentrations, and P had a lesser impact on egg hatching than N and NP. Resting eggs were able to maintain their vitality even in unfavourable environments during the enrichment phase, and they hatched in large numbers when favourable conditions arose. High concentrations of N and NP had a significant effect on the community structure of hatched zooplankton, mainly affecting the emergence of copepod nauplii from resting eggs. The findings suggest that levels of nutrient enrichment determine the emergence of zooplankton from resting egg banks. This study provides a reference for the potential replenishment of active populations by resting egg banks in eutrophic river environments. [ABSTRACT FROM AUTHOR]

Maria Sibylla Merian, a remarkable woman born in 1647, made significant contributions to the field of entomology through her study of insects and their interactions with other living creatures. Her observations and illustrations challenged widely accepted scientific beliefs, particularly Aristotle's theory of spontaneous generation. Merian's research took her to Suriname, where she studied the diverse species of insects and plants. Despite facing obstacles as a woman in the 17th century, Merian's privileged background and access to resources played a role in her success. The story of Bobbi Wilson, a young Black girl with a passion for entomology, highlights the racial and gender inequalities that persist in science today. Both Merian and Wilson demonstrate the importance of breaking down structural inequities in scientific education to create a more inclusive space for scientific discovery. [Extracted from the article]

Recruitment limitation is known to influence species abundances and distributions. Recognition of how and why it occurs both in natural and in designed environments could improve restoration. Aquatic insects, for instance, rarely reestablish in restored streams to levels comparable to reference streams even years after restoration. We experimentally increased oviposition habitat in five out of 10 restored streams in western North Carolina to test whether insect egg-laying habitat was limiting insect populations in restored streams. A main goal was to test whether adding oviposition habitat in the form of rocks that partially protrude above the water surface could be used to increase the abundance and richness of stream insect eggs and larval insects in restored streams. Adding egg-laying habitat enhanced several response variables (e.g., protruding rocks, number of eggs, egg masses, egg morphotype richness, and oviposition habitat stability) to levels similar to those found in reference streams. Following the addition of protruding rocks, egg mass abundance increased by 186% and richness by 77% in restored-treated streams. Densities of larval insects that attached their eggs to protruding rocks showed an overall pattern consistent with treatment effects due to the combination of nonsignificant and significant increases of several taxa and not just one taxon. Our results indicate that these stream insect populations are limited by oviposition habitat and that adding egg-laying habitat alleviated this component of recruitment limitation. However, the weaker larval response indicates that additional post-recruitment factors, such as egg or larval mortality, may still be limiting a full recovery of larval insect abundances in these restored streams. This study shows the importance of integrating information from animal life histories, ecology, and geomorphology into restoration practices to improve the recovery of aquatic insects, which are commonly used to assess water quality and the biological efficacy of stream restoration. [ABSTRACT FROM AUTHOR]

Experiments to ensure the safety of carbosulfan, to Trichogramma chilonis Ishii in terms of adult emergence and parasitization by direct spraying on egg card technique, revealed significant adverse effect on adult emergence and parasitization. The number of adult emergence ranged from 41.96 to 58.0 and, parasitization 12.62 to 32.6 per cent at 24 HAT; while it was 44.03 to 64.63 and 18.95 to 38.8 per cent respectively at 48 HAT for all the tested three doses of carbosulfan 25 EC @ 250, 500 and 1000 g a.i ha-1. Carbosulfan 25 EC @ 250g a.i ha-1, recorded maximum adult emergence (58.00 at 24 HAT and 64.63 at 48 HAT) and maximum per cent parasitization (32.60 at 24 HAT and 38.80 at 48 HAT). Hence usage of carbosulfan 250 EC is recommended only at the low dose of 250g a.i. ha-1. [ABSTRACT FROM AUTHOR]

BACKGROUND: 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. RESULTS: 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. CONCLUSIONS: 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. [ABSTRACT FROM AUTHOR]

The hypothesized role of stress-inducible heat shock proteins is to act as a buffer against environmental variations and affect fitness in suboptimal conditions. Our study examining the functions of heat shock protein 27 (Hsp27) in the eggs of the Mediterranean fruit fly (Ceratitis capitata). We utilized double-stranded RNA, specifically targeting the Hsp27 gene, to reduce its expression and assessed the consequent impact on egg viability. The investigation included the examination of early eggs (less than 6 hours post-laying) and late eggs (more than 42 hours post-laying), using varying concentrations (0.02, 0.1, and 0.2 µg/µL) of Hsp27 dsRNA. Control groups of eggs were dsRNA of ATPase, Cctra-2, or phosphate buffer solution (ph-B-S). Down-regulating Hsp27 dsRNA reduced the hatching rate of the eggs compared to the hatching rate in the control groups, especially in the ph-B-S group. The early eggs were more affected than the late eggs after soaking with Hsp27 dsRNA, where the Hsp27 dsRNA decreased the hatching rates to 12.91% early. The tested concentration of 0.2 µg/µL of Hsp27 dsRNA was achieved with the most significant reduction of 2.75 in egg viability. The sex ratio of insects hatched from treated eggs was investigated after hatching. After the down-regulation of Hsp27, there was no significant effect of the Hsp27 down-regulation on the sex ratio.