Anaesthesia methods play a crucial role in ensuring the integrity of the animal during experimental studies. This study investigates the impact of two anaesthesia methods, CO₂ and cold treatment, on an insect antennal response to synthetic alarm pheromone compounds. Adult worker hornets were anesthetised, and their antennae excised and tested using an electroantennography set-up with controlled stimulation of alarm pheromone components. Results showed that CO₂-anesthetised hornets exhibited robust antennal responses, while cold-anesthetised individuals displayed none. This result suggests that freezing may impair the functionality of olfactory receptors. In contrast, CO₂ anaesthesia preserves receptor integrity, offering reliable and interpretable results. This study highlights the importance of selecting appropriate anaesthesia techniques to avoid artefacts in insect sensory physiology research and underscores the ecological relevance of studying Vespa velutina nigrithorax alarm signalling.

Drosophila suzukii is a significant pest of soft- and thin-skinned fruit crops. Synthetic pesticides remain the primary control method; however, their use raises concerns about insect resistance and harmful pesticide residues in produce. Methyl jasmonate (MeJA), a plant growth regulator in the jasmonate family, plays a key role in plant defence against herbivores and has been identified as a repellent for arthropods of medical and veterinary relevance. This study examined the effect of MeJA on D. suzukii female oviposition and adult behaviour using two-choice bioassays. In a two-choice cage, doses above 1287.5 µg/filter paper deterred D. suzukii females from oviposition by more than 90% on artificial fruits. Using a two-choice planar olfactometer, MeJA also repelled both sexes with median repellent dose (RD50) values of 55.24 µg/filter paper for females, 55.03 µg/filter paper for males, and 55.14 µg/filter paper for total adults. Interestingly, MeJA demonstrated a dose-dependent dual effect: at 309.0 µg/filter paper, it functioned as a bio-repellent, while lower doses (3.86–15.45 µg/filter paper) acted as an attractant. This dual effect suggests that MeJA could serve as both a repellent and an attractant depending on its dose, with potential applications as a lure in traps.

This study presents the first record of Miyalachnus sorini Kanturski & Lee, 2024 (Aphididae: Lachninae) in South Korea, thereby extending its known distribution beyond Japan and identifying a new host plant, Prunus sargentii (Rosaceae). We describe diagnostic morphological traits across multiple life stages and compare them with those of Japanese populations. Comparative analyses with Japanese populations demonstrated consistent morphological differentiation, notably elevated ratios of the ultimate rostral segment to antennal segments across multiple morphs in the Korean population, indicating potential ecological adaptation. DNA barcoding using the mitochondrial cytochrome c oxidase I gene revealed low intraspecific divergence (average 0.2%) and interspecific divergence (average 10.5%) between Miyalachnus sp. and M. sorini. Haplotype analysis was performed to investigate the relationship between host plants and cryptic genetic diversity. These findings enhance our understanding of the morphological and genetic diversity of M. sorini and underscore the importance of monitoring its spread for informed pest management strategies.

True bugs (Hemiptera: Acanthosomatidae, Coreidae, and Pentatomidae) include harmful crop pests affecting global agriculture, with different species displaying distinct optimal conditions for development and using different habitats. Over a 2-year period, this research investigates how habitat variation and altitude can influence the species composition of true bugs and their egg parasitoids in South Tyrol (North Italy), unveiling different trends in their population and diversity across habitats: apple orchards, urban areas, and forests. A total of 25 true bug species were sampled. Urban environments hosted the highest bug abundance, predominantly driven by the invasive Halyomorpha halys, while forests showed a higher prevalence of native species such as Pentatoma rufipes and Palomena prasina. Altitude significantly influenced species composition, with H. halys and P. rufipes abundance negatively and positively correlated with altitude, respectively. A total of 12 parasitoid species (Hymenoptera: Eupelmidae, and Scelionidae) emerged from the field-collected bug eggs, including the exotic Trissolcus japonicus, predominantly associated with H. halys in urban areas. Native parasitoids exhibited higher parasitism rates on native bug species, indicating co-evolutionary relationships. The results give an insight into the ecological dynamics of local true bug species and their egg parasitoids, and highlight the value of natural and urban areas for conserving both hemipteran and parasitoid species richness and abundance.

The host plant associations of the bird cherry-oat aphid, Rhopalosiphum padi (L.), a major pest of wheat, before and after wheat harvest remain poorly understood. Overlapping growth of maize and wheat may promote R. padi survival and movement between crops. We examined population dynamics and constructed life tables for R. padi reared on wheat seedlings, maize husks, and maize leaves. Field-collected R. padi survived on both maize tissues, but aphid abundance declined sharply on aging maize leaves, while aphids on maize husks developed successfully. Aphids reared on wheat exhibited the fastest development, longest lifespan (27.89 ± 1.20 days), highest fecundity (98.59 ± 5.61 nymphs), and lowest mortality (2.56%). In contrast, aphids transferred to maize leaves showed reduced longevity (19.62 ± 1.16 days), lower fecundity (33.55 ± 2.47 nymphs), and higher mortality (23.73%). No significant differences in some reproductive parameters were observed between wheat- and maize husk-reared aphids, indicating relatively good performance on maize husks. Aphids transferred from wheat to maize experienced fitness costs, while aphids moved from maize husks back to wheat exhibited improved performance. These findings suggest that maize husks offer a comparatively favourable resource microhabitat for R. padi, potentially serving as a secondary host that supports population persistence after wheat harvest.

Understanding predator-prey dynamics is pivotal for advancing sustainable pest management strategies. This study examined the functional response of Harmonia axyridis across six developmental stages when preying upon the eggs of two destructive lepidopteran pests including Spodoptera litura and Spodoptera frugiperda. Using logistic regression and Holling’s disc equation, a clear Type II functional response was observed across all stages except first instars, indicating a density-dependent predation pattern constrained by handling time at higher prey densities. Adult females consistently emerged as the most potent predators, demonstrating the highest effectiveness of predation (1.591 on S. litura; 1.736 on S. frugiperda) and maximum predation rates (113.7 and 120.9 eggs, respectively). Adult males and fourth instar larvae also showed high predation capacities, with maximum consumption nearing 99 and 95 eggs. In contrast, first instars exhibited minimal predatory potential (effectiveness <0.017; maximum consumption <10 eggs), highlighting the critical role of developmental maturity in predation performance. Notably, predation on S. frugiperda eggs slightly surpassed that on S. litura, suggesting host-specific traits may modulate predator efficiency. The functional response curves confirmed a classic decelerating intake rate at high prey densities, characteristic of Type II predators. These findings affirm the high consumptive potential of H. axyridis, particularly adult females, as efficient natural enemies against Spodoptera spp. eggs, and provide actionable insights for their integration into targeted, stage-specific biological control programs.

Insect pupae change morphologically (e.g., pigmentation of eyes, wings, setae and legs) during the intrapuparial period. Knowledge on the physiological age of pupae and their emergence are important parameters for the control of agriculturally important Tephritid flies. Traditional methods for determining age require dissecting the puparium, thus killing the specimen. Therefore, non-invasive and more ethical methods to determine physiological age are needed, especially if individual pupae are followed throughout their development. Furthermore, machine learning methods can be employed to detect pupal age, thereby reducing human-bias. Here, we studied the intrapuparial development of the Mexican fruit fly, Anastrepha ludens (Diptera: Tephritidae), using non-invasive near-infrared (NIR, 850–1100 nm) images. We photographed pupae and subsequently analysed the images with machine learning algorithms. The intrapuparial period lasted between 17 and 19 days at a constant temperature of 26°C, and 75–80% relative humidity. No visible structures were observed between days 1 and 3. The phanerocephalic pupa was observed on day 4. The darkening of the eyes began on day 12. Wing pigmentation occurred on days 13 and 14, and the legs and setae on the thorax became melanized on day 15. A convolutional neural network correctly identified the physiological age range of intrapuparial development stages with an average accuracy of 71.77%. This model using NIR imaging allows the determination of a physiological age range without arresting the development of the pupae, and an estimation of the viability of pupae without waiting for the emergence of the adult.

Natural enemies serve a crucial role in crop protection through the regulation of pest population dynamics. Cyrtorhinus lividipennis is an important natural enemy of rice planthoppers. Fatty acid synthase (FAS), a multifunctional enzyme crucial for fatty acid biosynthesis, serves as a vital energy source for insect reproduction. However, the function of FAS in the reproductive processes of C. lividipennis remains incompletely understood. In this study, the ClFAS gene was successfully cloned from C. lividipennis. The open reading frame of ClFAS was 7224 bp, encoding a putative protein of 2407 amino acids. The expression levels of ClFAS were notably elevated in the fifth-instar nymphs, adults, as well as in the fat body and ovaries of female individuals. Silencing of ClFAS resulted in a reduction of 58.4%, 34.6%, and 49.0% in the expression levels of ClVg at 1-, 2-, and 3-days post-dsRNA injection, respectively. Furthermore, RNA interference (RNAi)-mediated depletion of ClFAS not only suppressed the Vg protein expression but also significantly impaired oocyte maturation and ovarian development. The fecundity of dsFAS-treated C. lividipennis females was markedly reduced by 49.5%, accompanied by significant decreases of 32.7% in oviposition duration and 26.3% in female adult lifespan. Our findings showed that ClFAS positively regulates the reproduction of C. lividipennis by promoting vitellogenesis and ovarian development, which provides valuable insights into how lipid metabolism governs fecundity in predatory insects.

Parasitoids are effective biocontrol agents against Spodoptera frugiperda. Here, we studied four egg parasitoids (Trichogramma chilonis, Trichogramma pretiosum, Trichogrammatoidea bactrae, and Telenomus remus) on S. frugiperda eggs under laboratory conditions [25 ± 1 °C, 70 ± 5% RH, 14/10-h (L:D) photoperiod]. Then, Tr. chilonis (the best trichogrammatid species in the laboratory) was studied inside cages (1 m × 1 m) under maize-field conditions. Egg-to-adult periods (days) were recorded among different species, with Te. remus having the longest (10.00 ± 0.89 days) and Tr. bactrae the shortest (7.80 ± 0.66 days) periods. Furthermore, Te. remus exhibited the greatest adult longevity (days) for both males and females, with and without food. Lifespan parasitism under laboratory conditions was the highest for Te. remus (73.60 ± 7.23 eggs), followed by Tr. chilonis (45.40 ± 2.56 eggs) and Tr. pretiosum (42.00 ± 3.70 eggs). Adult emergence (%) was always higher than 90% and the sex ratio was higher than 0.60 for the studied egg parasitoid species. In the cage experiments set up in uncontrolled field conditions, different release densities of Tr. chilonis (50,000, 100,000, and 150,000 parasitoids/ha) were studied. Release densities of 100,000 and 150,0000 parasitoids per hectare were the most effective rates for managing S. frugiperda, with recorded egg parasitism of 71.36% and 72.88%, respectively. These findings provide crucial insights into the biological attributes and parasitism potential of these parasitoids, indicating the optimal release density of 100,000 Tr. chilonis/ha as an integrated pest management strategy against S. frugiperda in maize ecosystems.

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a major invasive pest threatening maize production in India. Temperature strongly influences its development, reproduction and population dynamics. This study evaluated the biological performance of S. frugiperda on maize across seven constant temperature regimes (14 ± 1°C to 38 ± 1°C) under controlled laboratory conditions, using the age-stage, two-sex life table approach. Developmental time decreased significantly with rising temperatures, while survival and fecundity peaked at 26 ± 1°C and 30 ± 1°C. The highest values of net reproductive rate (R0 = 499.91 females/female), intrinsic rate of increase (rm = 0.25 females/female/day), and finite rate of increase (λ = 1.28 females/day) were recorded at 30 ± 1°C, followed by 26 ± 1°C (R0 = 467.32, rm = 0.24, and λ = 1.26, respectively). In contrast, thermal extremes delayed development and adversely affected both survival and reproduction. No development occurred at 38 ± 1°C. Population projections indicated rapid generational turnover at optimal temperatures, with up to nine generations annually at 26 ± 1°C. The temperature range of 26–30 ± 1°C was found to be optimal for both survival and reproduction of S. frugiperda, aligning with kharif season temperatures in North India, particularly Punjab. These conditions promote multiple generations annually, whereas extreme summer or winter temperatures may limit population development. The findings advocate for temperature-informed, location-specific pest control strategies. Intervening during critical developmental windows, especially at the egg and larval stages, can limit population buildup. Insights into the pest’s thermal adaptability contribute to the advancement of climate-resilient, sustainable pest management frameworks for maize systems in North India and similar agroclimatic regions.

Many species of spittlebugs (Auchenorrhyncha: Cercopidae) use sugarcane and other grasses as host plants, and when damage is extensive they are considered pests leading tom economic losses. Mahanarva fimbriolata and Mahanarva spectabilis are the most common in sugarcane and can be distinguished mainly by genital morphology. Recently, another morphotype of Mahanarva occurring in sugarcane fields that did not match the morphologies of either of these Mahanarva species mentioned above has been widely collected in Brazil, raising doubts on the identification of Mahanarva species using sugarcane. Accurate specimen identification is critical for sugarcane pest management, because misidentifications can lead to economic losses and inefficient control strategies. Thus, we combined morphology, geometric morphometrics, and molecular techniques to investigate the hypothesis that this morphotype could be considered a new species of Mahanarva. Morphological analyses included examination of male genitalia and tegminal colouration patterns. We also quantified hindwing shapes using geometric morphometrics; and performed a phylogenetic analysis using the mitochondrial COI gene. Morphological evidence distinguished the new morphotype through unique traits in male genitalia. Geometric morphometrics reliably separated species, with over 89% classification accuracy. Molecular analyses confirmed the morphotype as a distinct lineage closely related to M. fimbriolata and M. spectabilis. Thus, we describe M. diakantha sp. n., demonstrating the effectiveness of an integrative approach in resolving taxonomic challenges. Additionally, we provide formal diagnoses for M. fimbriolata and M. spectabilis. This work underscores the importance of precise taxonomy in agroecosystems, supporting sustainable pest management practices.

Rice water weevils (RWWs) (Lissorhoptrus oryzophilus) and rice weevils (RW) (Echinocnemus squameus) (both Coleoptera: Curculionidae) are major rice pests that cause significant economic losses in China. Understanding their potential distribution areas is crucial for effective management. This study used the Biomod2 package in R to simulate and predict the current and future potential distributions, changes in suitable areas, shifts in distribution centres, and overlaps under climate change for both pests under three greenhouse gas emission scenarios. By 2023, the suitable areas for RWWs and RWs were 538.52 × 104 km2 and 376.05 × 104 km2, respectively. The suitable area for the former pest expanded southwestward and northeastward across China, whereas the latter spread mainly into Northeast China. The suitable area for RWWs is projected to remain stable, whereas that for RWs is expected to decline. The distribution centroid of RWWs is anticipated to shift toward southeastern or southwestern Shaanxi, whereas RWs are likely to migrate toward central-eastern or northeastern Shaanxi. The niche overlap between the two pests is high (Schoener’s D = 0.658, I = 0.816), with overlap concentrated in central, eastern, and southern China. The key factors influencing their distributions include precipitation of the wettest month (Bio13), mean temperature of the warmest quarter (Bio10), and precipitation of the driest month (Bio14). This study provides a theoretical basis for the prediction of the potential distribution of both pests, which offers valuable insights for the development of effective pest control strategies in China.