There is interest in exploring biodegradable chemicals, e.g. sex pheromones, in behaviour manipulation to control the polyphagous mirid species Helopeltis bakeri Poppius. Understanding this insect pest’s reproductive behaviour is critical for identifying and isolating semiochemicals. H. bakeri rate of sexual maturation was determined by identifying the time the winged adult changed colour after the 5th and final nymphal form. We verified that there was no significant difference in the rate of colour change for both sexes. Copulation lasted an average of 167.0 ± 77.1 min and was observed on mating pairs >72 h old from the time of final molt. Close-range copulation behaviour of H. bakeri was recorded using the Behavioral Observation Research Interactive Software, and sequential behaviour analysis was performed by creating adjacency matrices. The ethograms revealed the absence of specific calling behaviour from either of the sexes. However, the male’s active pursuit of the female may indicate the latter’s role in releasing sex attractants. Using a wind tunnel, it was observed that the number of male visitations of 96-h to 120-h-old females significantly differed from the attraction in younger females (p < 0.05) and peaked from 2:00 PM to 12:00 AM. This supports the crepuscular nature of this mirid species. The difference in the sex maturation age and maximum male attraction implies that the secretion of sex attractant could happen after the completion of development, i.e. the exhibition of colour dimorphism.

Phycodes radiata is a significant pest of fig trees, causing extensive damage to fig orchards in the Semnan region of Iran in recent years. egg masses of P. radiata were collected from four Ficus carica cultivars, Zard Semnan, Ghermez Semnan, Zard Garmsar, and Ficus sp., and were subsequently reared under laboratory conditions. The study investigated the biological parameters of P. radiata when fed on four different fig cultivars. The feeding index parameters were significantly higher in the Zard Semnan cultivar than in the others. Hemocyte types observed in the larval hemolymph included prohemocytes, plasmatocytes, granulocytes, and oenocytoids, as identified via light microscopy. The pathogenicity of five isolates of entomopathogenic fungi: three isolates of Beauveria bassiana (B1, B2, and B3), one isolate of Metarhizium anisopliae, and one isolate of Lecanicillium muscarium were assessed against P. radiata larvae. The larvae were directly immersed in the fungal suspension for 6 seconds. Control larvae were treated similarly with Tween 80 (0.01%) and distilled water. Larval mortality was highest with the B2, B1, and B3 isolates, respectively. To evaluate hemocyte density in response to pathogenic fungi, fungal spores were injected into insect hemolymph, and hemocyte type changes were recorded at 1, 3, 6, 12, 24, 48, and 72 hours post-injection. The most pronounced effects were observed with the B1 and B2 isolates at 3 and 6 hours post-injection. Overall, the findings indicate that entomopathogenic fungi can effectively disrupt the growth and defense mechanisms of P. radiata, leading to impaired development and increased larval mortality.

The gut pH plays crucial roles in diet preference, habitat choice, insect fitness, and insect-microbial relationships. It significantly impacts enzyme activity efficiency, as well as the internalisation and efficacy of pesticides. Without a comprehensive understanding of the gut environment, potential pest management strategies cannot be fully optimised.

This study investigates the gut pH of the globally invasive pest insect Western flower thrips Frankliniella occidentalis, and the effect its Gram-negative symbiotic gut bacterium BFo2 has on pH modulation. Indicator dyes were fed to F. occidentalis and the gut pH was found to vary between 6 and 7. In general, the larval and adult guts appear to have a pH of between 6 and 6.5; however, the posterior gut of some adults appears to be closer to 7. This almost neutral pH offers a favourable environment for the neutrophilic symbiotic BFo2. The ability of BFo2 isolates to buffer pH towards neutral was also observed during in vitro culture using broths at different pH values.

This paper also discusses the implications of this gut environment on dsRNAi delivery. By laying the foundation for understanding how gut pH can be leveraged to enhance current pest management strategies, this study particularly benefits research aimed at optimising the delivery of lethal dsRNA through symbiont-mediated RNAi to Western flower thrips in pest management programs.

The tomato leafminer, Phthorimaea absoluta (synonym Tuta absoluta Meyrick, 1917), is a transboundary plant pest that poses a serious threat to global tomato cultivation and production, with significant negative social and environmental impact from increased insecticide usage for its management. We present three P. absoluta draft mitochondrial genomes (mitogenomes) from Malawi and South Africa, thereby increasing the mitogenome resources for this invasive agricultural pest. Comparative analysis with Spain, China, and Kenya samples revealed at least seven maternal lineages across its current invasive ranges, supporting multiple introductions as a major factor for the spread of invasive populations. Mitogenome results therefore identified unexpected diversity as compared to the use of the partial mitochondrial cytochrome oxidase subunit I (mtCOI/cox1) gene marker for the inference of P. absoluta invasion biology. The whole-genome sequencing approach further identified alternative mitochondrial DNA (mtDNA) gene regions necessary to improve diversity estimates, and enables concurrent characterisation of insecticide resistance genes. Characterisation of the VSSG (Para) and AChE-1/ace-1 gene profiles that underpin pyrethroid and organophosphate (OP) resistances, respectively, confirmed co-introductions of pyrethroid and OP resistance genes into Malawian and South African populations. Our study highlights the need for additional P. absoluta mitogenome resources, especially from native populations that is needed for more accurate interpretations of introduction pathways and the development of future sustainable management strategies.

Land use change has significantly altered most ecosystem functioning, such as nutrition provisioning, water flows and pollination services. So far, the impact of land use change on the dietary diversity of predatory insects has remained largely unexplored. In this study, we explored the prey composition of reared yellow-legged hornets Vespa velutina Lepeletier (Hymenoptera: Vespidae) in landscapes with a gradient of surrounding green lands, using metabarcoding of feces eliminated by larvae. The hornets primarily fed upon insects, with dipterans, coleopterans, lepidopterans, hemipterans, hymenopterans, and orthopterans being the dominant prey groups. The percentage of green lands had a significantly positive effect on prey richness at a spatial scale of 1500 m, but no effect on Shannnon index of the prey community. Meanwhile, the green lands had significantly positive effects on richness of coleopteran prey and lepidopteran prey, but no significant effect on richness of dipteran prey, hemipteran prey, hymenopteran prey, or orthopteran prey. In terms of beta diversity, the percentage of green lands explained the dissimilarity of prey communities among landscapes, whereas local factors, such as the distance to green lands and the distance to buildings, did not explain the dissimilarity. Our study indicated that the green lands in the landscape positively affected the dietary diversity of reared yellow-legged hornets, but this effect varied among different taxonomic groups of prey.

Asian corn borer, Ostrinia furnacalis Guenée (Lepidoptera: Crambidae), is a major pest in corn production, and its management remains a significant challenge. Current control methods, which rely heavily on synthetic chemical pesticides, are environmentally detrimental and unsustainable, necessitating the development of eco-friendly alternatives. This study investigates the potential of the entomopathogenic nematode Steinernema carpocapsae as a biological control agent for O. furnacalis pupae, focusing on its infection efficacy and the factors influencing its performance. We conducted a series of laboratory experiments to evaluate the effects of distance, pupal developmental stage, soil depth, and light conditions on nematode attraction, pupal mortality and sublethal impacts on pupal longevity and oviposition. Results demonstrated that S. carpocapsae exhibited the highest attraction to pupae at a 3 cm distance, with infection declining significantly at greater distances. Younger pupae (<12 h old), were more attractive to nematodes than older pupae, and female pupae were preferred over males. Nematode infection was highest on the head and thorax of pupae, with a significant reduction in infection observed after 24 h. Infection caused 100% mortality in pupae within 2 cm soil depth, though efficacy was reduced under light conditions. Sublethal effects included a significant reduction in the longevity of infected adults and a decrease in the number of eggs laid by infected females compared to controls. These findings underscore the potential of S. carpocapsae as an effective biocontrol agent for sustainable pest management in corn production, offering a viable alternative to chemical pesticides.

The oriental armyworm, Mythimna separata (Walker), is a highly migratory pest known for its sudden larval outbreaks, which result in severe crop losses. These unpredictable surges pose significant challenges for timely and accurate monitoring, as conventional methods are labour-intensive and prone to errors. To address these limitations, this study investigates the use of machine learning for automated and precise identification of M. separata larval instars. A total of 1577 larval images representing different instar were analysed for geometric, colour, and texture features. Additionally, larval weight was predicted using 13 regression models. Instar identification was conducted using Support Vector Classifier (SVC), Random Forest, and Multi-Layer Perceptron. Key feature contributing to classification accuracy were subsequently identified through permutation feature importance analysis. The results demonstrated the potential of machine learning for automating instar identification with high efficiency and accuracy. Predicted larval weight emerged as a key feature, significantly enhancing the performance of all identification models. Among the tested approaches, BaggingRegressor exhibited the best performance for larval weight prediction (R2 = 98.20%, RMSE = 0.2313), while SVC achieved the highest instar identification accuracy (94%). Overall, the integration of larval weight with other image-derived features proved to be a highly effective strategy. This study demonstrates the efficacy of machine learning in enhancing pest monitoring systems by providing a scalable and reliable framework for precise pest management. The proposed methodology significantly improves larval instar identification accuracy and efficiency, offering actionable insights for implementing targeted biological and chemical control strategies.

Oenopia sauzeti (Mulsant) (Coccinellidae: Coleoptera) is a highly efficient predator of sap-sucking insect pests due to its high feeding capacity and broad prey range. The present investigation was carried out to find out the feeding potential and functional response of O. sauzeti fed on different densities of Macrosiphum euphorbiae (Thomas) (Aphididae: Hemiptera) nymphs in the in vitro condition with the overarching objective of appraising the ladybird beetle’s potential as a distinguished biological control agent. The newly emerged coccinellid grubs of a particular stage were reared individually on Petri plates with a known number of M. euphorbiae nymphs of a particular stage. The single individual of O. sauzeti consumed 1104.53, 936.53, 634.07, and 473.20 aphids in one generation when reared on the first, second, third, and fourth instars of M. euphorbiae, respectively. The female adult of predator recorded as a more voracious feeder compared to the male adult. O. sauzeti exhibits a type II functional response against potato aphid, and a significantly negative linear coefficient was obtained after logistic regression analysis for the proportion of prey consumed (Na/N) as a function of initial prey density (N). The functional response parameters, i.e. attack rate and handling time, were estimated by applying Roger’s random predator equation. The attack rate increased, and handling time decreased with the advancement of the development stage of the predator. The voracious nature of both adults and grubs of the ladybird beetle makes this effective biocontrol agent to be used in the Integrated Pest Management Programme against the potato aphid.

The effects of rainfall and temperature on the seasonal phenology of ant nuptial flights in a forest locality in Ghana was studied for 42 months using a light-trap. A total of 204393 ants was caught. Of the 135 species/morphospecies collected, 40 could not be identified beyond genus, and males of a further 14 beyond subfamily. The commonest 65 species/morphospecies flew a mean of 10.1 ± 0.4 months per year. With the exception of males of Dorylus atriceps, Platythyrea conradti, Plat. modesta, Crematogaster nr striatula plus gynes of Plagiolepis brunni and Cr. [F257], whose peak flights occurred in the main dry season, flight activity coincided with the onset of the rainy seasons. Both sexes of Pheidole megacephala, P. speculifera, Tetramorium aculeatum, and Paraparatrechina albipes plus gynes of Cr. striatula and males of Anochetus africanus, Hypoponera dulcis, Cr. kneri, and T. guineensis flew more frequently on rainy than dry dates. Nineteen species were caught more frequently on dry than on wet dates including most Camponotus, Tapinoma, and Technomyrmex spp. Fifteen species/morphospecies responded positively to increasing monthly rainfall, six to increasing monthly temperatures, and five to the interaction between these factors, with males of A. pellucidus, H. dulcis, and Cr. striatula caught more frequently in wetter, warmer months, and those of Camponotus olivieri and Technomyrmex andrei in drier, warmer ones.

For insects whose larvae are incapable of moving between food resources, the selection of oviposition sites by females is critical to the survival and development of their offspring. In such insects, it is known that females utilise and benefit from conspecific cues for oviposition choice. Studying how information from the behaviour of conspecifics affects egg-laying decision-making is crucial for understanding the biology of insects, which can lead to novel strategies for pest management. We focused on the reproductive behaviour of the Asian long-horned beetle Anoplophora glabripennis, which has become an invasive pest species throughout the world. Here, we show that A. glabripennis avoids sites already containing conspecific cues during egg-laying decision-making. The field survey measuring the distance between neighbouring oviposition scars (in this species, females make scars through the bark of host branches for laying eggs) suggested that the selection of oviposition sites by females is not random. In laboratory oviposition-choice bioassays, females made less oviposition scars on branches containing scars made by other females than those without scars. In addition, female oviposition was also deterred by the presence of their own oviposition scars. Our results indicate that avoiding sites containing conspecific (and their own) traces realises fitness benefit such as reducing resource competition among larvae. This study provides insights into the reproductive behaviour of this invasive longhorn beetle, which is useful for developing environmentally friendly control methods such as oviposition deterrents.

Understanding of predators functional responses is critical in assessing their efficiency as biological control agents. This study investigates the functional responses of three coccinellid predators Scymnus posticalis Sicard (Coleoptera: Coccinellidae), Platynaspis saundersi Crotch (Coleoptera: Coccinellidae), and Pharoscymnus horni Weise (Coleoptera: Coccinellidae) against varying densities of the prey aphid, Myzus persicae (Hemiptera: Aphididae) under controlled conditions (25 ± 1°C temperature, 70 ± 5% relative humidity and 14 L:10D photoperiod). Predation trials across different prey densities were performed with these adult coccinellid predators. Logistic regression analysis confirmed a Type II functional response for all the three species used in the experiments. Among the three, S. posticalis showed a superior predatory efficiency, with the highest attack rate (a) (0.0994 h−1), shortest handling time (Th) (0.5016 h) and a maximum theoretical predation rate (K) of 48.76 aphids. P. saundersi and P. horni showed lower predatory parameters, positioning S. posticalis as the most efficient predator. These findings underscore S. posticalis as a promising candidate for biological control of M. persicae, with a clear advantage in predation metrics over P. saundersi (a = 0.0876 h−1; Th = 0.5193 h; K = 48.27 aphids) and P. horni (a = 0.0695 h−1; Th = 0.5316 h; K = 47.97 aphids). However, further field validation is essential to assess its real-world efficacy, considering environmental variability and complex ecological interactions.

The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a highly destructive polyvorous pest with a wide host range and the ability to feed continuously with seasonal changes. This destructive pest significantly damages crops and can also utilize non-agricultural plants, such as weeds, as alternative hosts. However, the adaptation mechanisms of S. frugiperda when switching between crop and non-crop hosts remain poorly understood, posing challenges for effective monitoring and integrated pest management strategies. Therefore, this study aims to elucidate the adaptability of S. frugiperda to different host plants. Results showed that corn (Zea mays L.) was more suitable for the growth and development of S. frugiperda than wheat (Triticum aestivum L.) and goosegrass (Eleusine indica). Transcriptome analysis identified 699 genes differentially expressed when fed on corn, wheat, and goosegrass. The analysis indicated that the detoxification metabolic pathway may be related to host adaptability. We identified only one SfGSTs2 gene within the GST family and investigated its functional role across different developmental stages and tissues by analysing its spatial and temporal expression patterns. The SfGSTs2 gene expression in the midgut of larvae significantly decreased following RNA interference. Further, the dsRNA-fed larvae exhibited a decreased detoxification ability, higher mortality, and reduced larval weight. The findings highlight the crucial role of SfGSTs2 in host plant adaptation. Evaluating the feeding preferences of S. frugiperda is significant for controlling important agricultural pests.