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.

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.

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.

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.

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.

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.

Spodoptera frugiperda (Lepidoptera: Noctuidae), commonly known as the fall armyworm (FAW), is an invasive pest known for its rapid migration, strong adaptability, and wide host range. Small heat shock proteins (sHsps) are a specific class of Hsps associated with the molecular mechanisms of insect growth and development and the response to abiotic stresses, such as extreme temperatures, ultraviolet (UV) rays, and pesticides. Herein, six sHsps, SfsHsp11.2, SfsHsp15.8, SfsHsp20.2, SfsHsp21.4, SfsHsp22, and SfsHsp26.6, were successfully cloned and identified from FAW. The six SfsHsps all have an α-crystallin domain in their amino acid sequences. Furthermore, we investigated the expression patterns of these six SfsHsps in different tissues and developmental stages of FAW using real-time quantitative polymerase chain reaction. Their expression levels in adult FAW were also analysed under extreme temperatures (36°C and 4°C) and UV-A stress for different durations (0, 30, 60, 90, and 120 min). Our findings revealed distinct expression profiles for the six SfsHsps in different FAW tissues and developmental stages. Notably, under temperature and UV-A stress, most SfsHsp genes were significantly upregulated in adults. Our findings strongly indicate that SfsHsps are crucial in the development and stress response of S. frugiperda.

Spermophagus niger L. is a well-known pest of roselle (Hibiscus sabdariffa L.) seeds in West Africa and responsible of mostly damage. This study first reported the presence of S. niger Motschulsky in kenaf (Hibiscus cannabinus L.) seeds stored. Samples of kenaf seeds collected at four locations in Burkina Faso. In the laboratory, the seeds were incubated until adults’ insects emerged. The emerged insects were first identified morphologically and their biodemographic parameters studied under controlled conditions (32°C ± 0.1, 43% ± 1 r.h.). The results showed that S. niger (Coleoptera: Chrysomelidae) was the only pest encountered on H. cannabinus seeds in storage and was able to complete its development cycle there. Over the course of its life, which lasts an average of 7 days, the female laid around 40 eggs, resulting in 24 individuals dominated by females. The embryonic and total development time were average 5 and 26 days, respectively. Spermophagus niger population doubled in 6 days, with an intrinsic rate of natural increase of 0.105. The finite rate of increase and the generation time averaged 1.11 and 31.86 days, respectively. This study pointed out for the first time that S. niger is able to evolve successfully on H. cannabinus seeds in storage conditions and therefore, could be a serious pest of this important crop. The data from this study could therefore be used as a basis for the post-harvest management of H. cannabinus seeds.

Gene expression can be quantified using the sensitive technique of quantitative reverse transcription real-time polymerase chain reaction. Inter-sample variances can be minimised through normalisation with an appropriate reference gene. Bemisia tabaci, a significant insect vector of the Begomovirus family, transmits the Tomato Leaf Curl Bangalore Virus, for which there is a dearth of information regarding appropriate reference genes for autophagy. The viral load surpasses the vector’s capacity when autophagy is activated, which is also detrimental to whiteflies, particularly concerning virus translocation. To mitigate this vector using a double-stranded RNA approach, a precise measurement of gene silencing is required. For this investigation, normalisation of housekeeping or internal control genes is necessary. The present work utilised software tools such as geNorm, NormFinder, and BestKeeper to assess the suitability of five reference genes, namely, α-tubulin, β-tubulin, elongation factor, actin, and sucrose synthase, for gene expression studies in viruliferous and non-viruliferous B. tabaci. The analysis of the data showed that β-tubulin, which exhibits more stable expression, is the best-ranked reference gene. Furthermore, the reference genes were verified using the target gene expression of atg3 (an autophagy gene). The current findings enable precise measurement of gene expression in begomovirus-induced autophagy conditions of B. tabaci.

Panonychus citri is a significant pest of Rutaceae plants. Chitin deacetylase is a key gene in chitin metabolism and the insect molting process. In this study, The PcCDA1 and PcCDA2 genes of P. citri were cloned and identified. The expression of PcCDA1 was higher during the egg stage, while PcCDA2 exhibited the highest expression during the larval stage, with their expression levels showing a clear periodicity. Using RNAi technology to silence the expression of the PcCDA1 and PcCDA2 genes in the mite, the results indicated that only 20.85% successfully molted, while the deformity rates were 78.81% and 85.44%, respectively. HE staining and microscopic observation revealed that silencing PcCDA1 and PcCDA2 caused an increase in the epidermal thickness of P. citri by 1.87 μm and 5.706 μm, respectively. Additionally, silencing PcCDA also significantly reduced the relative mRNA expression levels of chitin synthesis genes (PcCHS1 and PcCHS2) and degradation genes (PcCHT1, PcCHT2, and PcCHT4). These results suggest that the PcCDA gene is crucial for normal molting and epidermal development, providing new scientific evidence for molecular target-based green pest control strategies.

Parasitoid–host interactions are key drivers of insect community structure, and host concealment is known to influence both parasitoid diversity and parasitism rates. However, the effectiveness of different host defence strategies in mitigating parasitism remains insufficiently understood. In this study, we examined how the level of host concealment affects parasitoid communities and parasitism rates in two microlepidopteran species living on hops (Humulus lupulus L.): Caloptilia fidella, which employs a leaf-rolling strategy, and Cosmopterix zieglerella, a strict leaf-miner. We collected a total of 774 and 150 host-infested leaves for C. fidella and C. zieglerella, respectively. Parasitism rates were calculated as the proportion of leaves from which parasitoids emerged and were averaged across three years. We combined traditional morphological identification with molecular species delimitation based on ITS2 and CO1 markers, employing ASAP (Assemble Species by Automatic Partitioning) and Bayesian Poisson Tree Processes (bPTP) methods to refine parasitoid taxonomy and detect cryptic species. Our results showed that semi-concealed C. fidella larvae in leaf rolls experienced significantly higher parasitism rates than their mining stages, while fully concealed C. zieglerella larvae exhibited generally lower parasitism. Molecular analyses confirmed idiobiont strategies in several parasitoid species, including Sympiesis acalle, S. sericeicornis, and Elachertus fenestratus, and bPTP outperformed ASAP in detecting cryptic diversity. These findings suggest that, in the studied system, leaf-mining offers more effective protection from parasitoids than leaf-rolling. Additionally, the study highlights the value of molecular tools in species delimitation and underscores their importance for improving parasitoid taxonomy and advancing our understanding of host–parasitoid dynamics.

Understanding the circadian rhythms of bark and ambrosia beetles (Scolytinae) is crucial for assessing their dispersal strategies, trophic specialisation, and microhabitat preferences. This study investigated circadian rhythms in Scolytinae communities using flight interception traps in an oak forest in the southern part of Czechia. Ordination biplot revealed a flight activity gradient, with nocturnal dispersers distinct from diurnal species. Species richness gradually decreased from the 20:00–24:00 interval through to the 12:00–16:00 interval, with the most notable decline observed between the 08:00–12:00 and 12:00–16:00 intervals. A combination of fourth-corner and partial canonical correspondence analyses identified tribal affiliation, trophic specialisation, and microhabitat preference as key drivers of flight structuring. Members of the tribe Xyleborini showed negative association to the 16:00–20:00 interval. Xylomycetophagous species, such as Xyleborinus saxesenii exhibited multimodal activity peaks, with increased flight from nighttime to early morning. In contrast, species that feed in the phloem such as Scolytus intricatus showed no significant association with any specific time interval. Several species that utilise stumps as potential breeding substrates showed significantly reduced flight activity during the crepuscular period, which supports the hypothesis that microhabitat preference contributes to diel periodicity. Our findings show the complex interplay between abiotic and biotic factors in shaping circadian flight periodicity, which leads to distinct flight activity patterns between Scolytini bark and Xyleborini ambrosia beetles. These results emphasise the ecological significance of maintaining heterogeneous forest structures that provide a balance of shaded and sun-exposed deadwood habitats to support diverse assemblages.

American silk moth, Antheraea polyphemus Cramer 1775 (Lepidoptera: Saturniidae), native to North America, has potential significance in sericulture for food consumption and silk production. To date, the phylogenetic relationship and divergence time of A. polyphemus with its Asian relatives remain unknown. To end these issues, two mitochondrial genomes (mitogenomes) of A. polyphemus from the USA and Canada respectively were determined. The mitogenomes of A. polyphemus from the USA and Canada were 15,346 and 15,345 bp in size, respectively, with only two transitions and five indels. The two mitogenomes both encoded typical mitochondrial 37 genes. No tandem repeat elements were identified in the A+T-rich region of A. polyphemus. The mitogenome-based phylogenetic analyses supported the placement of A. polyphemus within the genus Antheraea, and revealed the presence of two clades for eight Antheraea species used: one included A. polyphemus, A. assamensis Helfer, A. formosana Sonan and the other contained A. mylitta Drury, A. frithi Bouvier, A. yamamai Guérin-Méneville, A. proylei Jolly, and A. pernyi Guérin-Méneville. Mitogenome-based divergence time estimation further suggested that the dispersal of A. polyphemus from Asia into North America might have occurred during the Miocene Epoch (18.18 million years ago) across the Berling land bridge. This study reports the mitogenome of A. polyphemus that provides new insights into the phylogenetic relationship among Antheraea species and the origin of A. polyphemus.