Bulletin of Entomological Research最新文献

Fruit flies are the most serious problem in fruit production worldwide, causing severe losses in production and fruit quality. The use of parasitoids, especially Diachasmimorpha longicaudata (Ashmead) (Hymenoptera, Braconidae), is an important tool for suppressing the fruit fly population. The objectives of this study were to determine the exposure time, density, and ideal larval instar of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) and to verify whether the parasitoid's previous experience affects its interaction with the host insect and the influence of these factors on the parasitism rate. In three bioassays, fly larvae were placed in 'parasitism units' to test different methods of exposure to female parasitoids. The variables included the previous experience of the female parasitoid with oviposition, the exposure time (30, 60, 120, 240, and 480 min) of the larvae to the parasitoid and the number (5, 10, 15, and 20) and instar (second and third) of the fly larvae. The flies and parasitoids that emerged were quantified, and the parasitism rate and sex ratio of the parasitoids were calculated. The results of the present study indicate that to increase the parasitism rate of D. longicaudata, third-instar larvae of C. capitata must be grouped into parasitism units of 20 larvae and exposed to a single female of the parasitoid for 8 h.

The legume pod borer, Helicoverpa armigera (Hübner), is one of the pervasive and destructive pests of legume crops, causing significant yield losses. In this study, we evaluated the nutritional performance and digestive enzyme activities of H. armigera when fed on ten mung bean varieties, including Baghmalek, India, Veys, Omrani, Parto, Simite1, Simite2, VC6371, VC3960, and VC6368. Additionally, biochemical profiling of these mung bean varieties, assessing starch, protein, anthocyanin, total phenolic and flavonoid content, was conducted to explore potential correlations with the nutritional physiology of H. armigera. The findings indicated that the larvae fed on Parto had lowest approximate digestibility, efficiency of conversion of ingested food, and relative growth rate, while those fed on VC6371 had the highest values. The values of efficiency of conversion of digested food were lower on Baghmalek and Parto and higher on VC6368 and VC6371. The lowest value of larval gain weight was on Parto. The highest proteolytic and amylolytic activities of larvae were observed on Veys and India, respectively; while the lowest enzyme activities were recorded on Parto. Our findings indicate that the low protein content combined with high levels of anthocyanin, total phenolics, and flavonoids may contribute to the potential tolerance of mung bean varieties against H. armigera. Cluster analysis revealed that VC6368 and VC6371 were the most suitable varieties for H. armigera development, whereas Baghmalek and Parto were nutritionally less suitable and may severe as promising candidates for breeding or cultivation to minimise damage caused by this pest.

The immunomodulatory effects of Ziziphus jujuba Mill. fruit extracts were investigated using Galleria mellonella as an insect immune model. The expression of antimicrobial peptides, hemolin, phenoloxidase genes (PO-I and PO-II), and enzyme activity was measured in response to Candida albicans, silica beads, and Z. jujuba fruit extract. Responses were found to be stimulus- and time-dependent. Gallerimycin and galiomycin, key antimicrobial peptides, exhibited distinct expression patterns, with gallerimycin showing a more pronounced response to pathogens and beads. The Z. jujuba extract stimulated an early but balanced immune activation, likely due to its bioactive compounds. Hemolin expression varied between larvae and haemocytes depending on the type and duration of the challenge, supporting its role in immune recognition and opsonisation. Phenoloxidase activity and gene expression were also enhanced, supporting their role in promoting melanisation processes. Docking analyses suggested that hemolin contributes to phenoloxidase activation by stabilising PO-I and interacting with the phenoloxidase-activating factor-1-like protein (PAP1). The findings suggest that Z. jujuba extract effectively modulates immune responses, promoting enhanced protection while maintaining immune balance. GC-MS analysis revealed multiple bioactive compounds potentially contributing to immune modulation. This study highlights the significant immunomodulatory effects of Z. jujuba fruit extract on the immune system of G. mellonella. The findings suggest its potential as a natural immunostimulant and warrant further investigation of the underlying molecular mechanisms and bioactive components.

This study tested the effects of soil amendment with orange peel powder (Citrus sinensis L.) on Brassica rapa growth, the performance of the aphid Myzus persicae Sulzer, and the foraging behaviour of its parasitoid Aphidius gifuensis Ashmead. Three peel: soil ratios (1:10, 1:15, 1:20 w/w) were compared with an unamended control. The 1:10 amendment significantly reduced seed germination, plant height, leaf size, and fresh weight, while the 1:20 amendment also decreased fresh weight. Aphid nymphal development was significantly delayed in the 1:10 and 1:15 treatments, and adult weight gain was reduced in the 1:15 treatment. Aphid population growth and parasitoid foraging time were unaffected across treatments. The results indicate that orange peel amendments can delay aphid development but also suppress plant growth at higher concentrations, highlighting the need for optimized application rates. This study supports further exploration of orange peel as a sustainable soil amendment in integrated pest management.

Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae), commonly known as potato aphid, is an economically damaging pest in tomato agroecosystem. Farmers often resort to chemical insecticides for its control, but this approach poses long-term ecological challenges. Biological control, which involves the strategic use of natural enemies, offers a more sustainable and effective alternative for managing insects. The syrphid, Episyrphus viridaureus (Weidemann) (Diptera: Syrphidae) is a natural predator of potato aphid within tomato fields. However, comprehensive information on its developmental biology, population growth parameters, predatory potential and functional response remain limited, prompting this study. In the present study, E. viridaureus was able to complete its lifecycle successfully while feeding on M. euphorbiae with an intrinsic rate of increase (r) (offspring/individual/day) of 0.103 and finite rate of increase (λ) (offspring/day) of 1.108. The larvae of E. viridaureus consumed 332.35 aphids out of which third instar larvae made the maximum contribution by consuming 232.69 aphids. All the three larval instars exhibited a type-II functional response against different densities of M. euphorbiae. Functional response parameters like attack rate (a) increased and handling time (T_h) decreased as the larval stages advanced. This research highlights the potential of E. viridaureus as an effective biocontrol agent against M. euphorbiae, contributing to sustainable pest management.

Bemisia tabaci is one of the most important agricultural pests worldwide, and the combined application of multiple natural enemies such as predators and parasitoids can potentially control B. tabaci. The study examined whether the predator Orius similis and the parasitoid Encarsia formosa can synergistically control B. tabaci (crop: kidney bean). The greenhouse cage method was used to release O. similis and E. formosa alone or in combination in different ratios. The combined release of O. similis and E. formosa synergistically decreased the B. tabaci population when compared with O. similis or E. formosa alone. Additionally, O. similis + E. formosa decreased the number of E. formosa black pupae and adults in each crop stage. However, the niche overlap index of E. formosa with B. tabaci nymphs in the O. similis + E. formosa group was higher than in the E. formosa group. Grey correlation analysis revealed that the correlation degree between natural enemies and B. tabaci was the highest when the O. similis and E. formosa release ratio was 1:3. These findings indicate that the combined release of O. similis and E. formosa synergistically controlled B. tabaci with the release ratio 1:3 being optimal for field application.

Saissetia oleae (Oliver) (Hemiptera: Coccidae) is a major pest of olive trees that requires effective biological control methods. This study evaluated the predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) for its predation efficiency against S. oleae eggs and nymphs under laboratory (25 ± 1 °C, 60 ± 10% RH) and screenhouse (25 ± 4 °C) conditions. Two laboratory trials were conducted over 6 days: Trial 1 assessed predation on S. oleae eggs, and Trial 2 on nymphs. Additionally, screenhouse trials tested four predator-prey ratios (T1: 1:2, T2: 1:4, T3: 1:8, T4: 1:10, adult A. swirskii to S. oleae eggs), with weekly observations over 10 weeks. Under laboratory conditions, A. swirskii caused significantly higher mortality in eggs (17.9 eggs consumed) than in nymphs (10.2 nymphs killed) by day 6, while mortality in control groups remained low (1.5 eggs, 2.0 nymphs). In screenhouse trials, A. swirskii significantly reduced S. oleae populations at all predator-prey ratios, with the 1:2 ratio achieving the greatest suppression, reducing densities to 0 eggs and 6 nymphs per plant by week 10, compared to 30 eggs and 110 nymphs in untreated controls. Predator populations increased in a density-dependent manner (T1 > T2 > T3 > T4). Treated plants maintained a high visual quality score (≥9.5 at week 10), whereas untreated plants showed a severe decline (0.9 at week 10). These results demonstrate that A. swirskii effectively suppresses S. oleae and holds promise as a sustainable biological control agent in integrated pest management for olives.

The Hyphantria cunea (Drury) is a highly polyphagous invasive pest that has become widespread and destructive in China. Although sex pheromone components of H. cunea have been identified, the weak field attraction of synthetic sex pheromone has hindered the application of sex pheromone-based lures in efficient monitoring and management of this pest. In this study, the electroantennographic (EAG) and field responses of H. cunea male adults to three synthetic sex pheromone components, including Z9, Z12, Z15-18Ald (C18:Ald), Z3, Z6-9S,10 R-epoxy-21Hy (C21-2Epo), and 1, Z3, Z6-9S,10 R-epoxy-21Hy (C21-3Epo), were evaluated. Male antennae exhibited significant dose-dependent response to three individual components and a ternary mixtures. The younger and virgin male moths showed stronger electrophysiological activity to synthetic compounds, whereas sensitivity decreased significantly after mating. Among the three components, C21-3Epo elicited the strongest antennal responses. Field trapping revealed that neither single compounds nor binary blends attracted males, whereas only the ternary blend of C18:3Ald, C21-2Epo, and C21-3Epo (ratio 8:1:1; 10 mg total load) effectively captured large numbers of males. In addition, the field trapping indicated that the green rubber septum functioned as a practical dispenser for synthetic pheromones. The Unitraps baited with the green rubber septum showed significantly higher trapping efficiency than cotton wicks, highlighting the septum as a promising dispenser for field deployment of synthetic sex pheromones. Finally, the green rubber septum baited with a ternary blend monitored the dynamics of H. cunea occurrence and detected that the emergence period overlapped with the commercially available synthetic lure. In general, the bioactivity of the synthetic sex pheromone of H. cunea was validated. It could effectively capture H. cunea male adults, be used to monitor and control H. cunea, and further be incorporated into the integrated pest management programme.