Parasitoids play a key role in biological control, regulating pest populations in natural and agricultural ecosystems. Their efficiency depends on a thorough understanding of host–parasitoid interactions. Among these, the functional response, the relationship between parasitism rate and host density, plays a critical role. Despite a well-established background, challenges remain in experimental design, model selection, and parameter estimation for functional response analysis in parasitoids. This study aims to provide a practical guide to addressing these challenges. We outline key considerations in experimental design, including the selection of model organisms and initial host densities. For model selection, we present methods to differentiate between Type II and Type III functional responses, identifying the best-fitting models for parasitoids. In parameter estimation, we present an example demonstrating the application of functional response models for each type, including parameter estimation to guide model choice. Additionally, we provide equations and code based on published data to facilitate parameter comparisons. This guide provides a structured framework for experimental design, parameter estimation, and model selection in functional response studies, which is adaptable to various host–parasitoid interactions. By enhancing methodological rigour, we aim to support researchers in improving the precision and applicability of functional response analyses in parasitoid research.

This study investigates the gut microbiota of newly emerged adult females and males of five economically important Anastrepha species (Tephritidae) – A. ludens, A. obliqua, A. serpentina, A. striata, and A. fraterculus – by analyzing 16S rRNA amplicon sequences from 36 samples collected from ecologically relevant fruit hosts and locations in Mexico. We chose to concentrate only on newly emerged adults to identify bacteria that females could potentially transmit vertically to progeny via oviposition, a topic that remains poorly studied. Results revealed that Proteobacteria dominated the microbiota in all species, but substantial variation was observed in genus-level composition. Differentially abundant genera included Enterobacter, Gluconobacter, Tatumella, Providencia, Ochrobactrum, Siccibacter, Sphingobacterium, and Sphingobium. Significant differences in alpha diversity were observed between species, particularly between A. obliqua and A. striata, and between A. obliqua and A. serpentina based on the Shannon index. Anastrepha ludens, A. obliqua, and A. striata males exhibited higher species richness than females, although these differences were not statistically significant within individual species likely due to limited sample size. Interestingly, across all species, significant differences in microbiota composition were observed between males and females. Our findings suggest that morphological, physiological (i.e., metamorphosis) and ecological factors, such as possible gut structural differences and host fruit preferences, may influence the composition of the gut microbiota, potentially affecting the ecological adaptability and pest behavior of these flies.

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.

The fungus Beauveria bassiana (Unioeste 76) was tested against the soybean pest Euschistus heros in laboratory, greenhouse, and field. In the laboratory, insects were sprayed with pure conidia (TC) suspended in distilled water or in an oil dispersion formulation (OD; vegetable oil) at a concentration of 109 conidia/mL. The UV-B radiation and heat tolerance of the conidia were also assessed. After 12 days, the mortality rates in the laboratory were 70% for the TC treatment and 80% for the OD treatment. In the greenhouse pre-infestation bioassay, which used soybean plants in cages, the fungal treatments resulted in 52% and 47% mortality for the TC and OD formulations, respectively. In the post-infestation bioassay, both fungal treatments caused 83% mortality. In the field trial conducted on soybean plots (14 × 18 m), the treatments included: (i) biological: OD (109 conidia/mL); (ii) chemical insecticide; (iii) biological + chemical, all applied at 150 L/ha. Insect numbers were evaluated using beating-sheet sampling. In the final population sample, the biological treatment showed a population density similar to the chemical treatment (0.94 and 0.83 insects/m, respectively), both below the economic threshold. Conidia tolerance to UV-B radiation was similar across both treatments, but conidia in oil were less tolerant to heat. These results suggest that strategically combining both approaches (B. bassiana with chemical insecticides), with careful consideration of application intervals, could provide a sustainable and effective method for managing natural populations of E. heros.

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.

Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) is one of the most serious pests of rice. The variations in phytoconstituents of rice cultivars (Miniket, Cottondora Sannalu, Gobindobhog, Swarna, and Tulaipanji) that led to differences in population growth of S. cerealella were studied. Fitness of the moth was approximated in terms of mean generation time (Tc), net reproductive rate (NRR or R0), intrinsic rate of population increase (rm), etc. Considering potential fecundity (Pf), growth rates, mortality coefficient (MC), and expected population size in the second generation (PF2), we classified the susceptibility of the rice cultivars to S. cerealella in the order as M > C > G > S > T. This was despite the higher concentrations of all the tested primary metabolites (PMs) in C and T. The least susceptibility of T and lower susceptibility of C than M can be attributed to their higher levels of secondary metabolites (SMs). M was highly susceptible due to its lowest SM content and sufficient levels of PMs. Now, G and S contained lower amounts of SMs, but they were moderately susceptible owing to the lower PM content. This emphasises the role of SMs, such as phenols, flavonoids, tannins, saponins, alkaloids, phytates, and oxalates, in determining the susceptibility of crop cultivars. Although none of the rice cultivars were entirely resistant, it can be stated that Miniket requires more protection measures against S. cerealella during storage than the others.

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 study systematically investigated the key biological and ecological characteristics of Cyamophila willeti, a major pest of the tree species Styphnolobium japonicum. We focused on its circadian mating rhythm, oviposition preference, and the effects of temperature on population parameters. Using the age-stage, two-sex life table approach, we compared the development, reproduction, and population growth potential under different temperature conditions. Results showed that mating activity peaked at 12:00 and 17:00, with females significantly preferring shoot tips for oviposition. At 25°C, female and male adult longevities were 39.88 ± 0.93 and 46.71 ± 1.69 days, respectively, and the mean fecundity per female was 647.75 ± 52.94 eggs. At 29°C, longevity was significantly reduced to 11.88 ± 4.10 days for females and 13.89 ± 4.31 days for males, while fecundity decreased to 47.63 ± 4.26 eggs. Most nymphs did not develop beyond the fifth instar at 33°C. These findings indicate that the optimal temperature for population growth of C. willeti is around 25°C, whereas high temperatures (≥29°C) significantly suppress survival and reproduction. This study establishes a foundation for monitoring C. willeti and developing effective control strategies.

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.

The objective of this experiment was to evaluate the resistance of advanced tomato genotypes resulting from an interspecific cross between Solanum lycopersicum and Solanum pennellii to Tetranychus urticae and Phthorimaea absoluta. The plant materials included nine lines, 14 hybrids, Leblon F1 (commercial control), and the wild accession S. pennellii LA716 as a resistance standard. Acylsugar content was then determined. For mite bioassays, oviposition, adult mortality/survival, egg hatching, and nymphs were evaluated using a no-choice bioassay. For P. absoluta bioassays, the oviposition, intensity of damage, type of lesions, and percentage of damaged leaflets were evaluated. F1 (TOM-808 × BPX-443E-03-02-113-02), F1(TOM-810 × BPX-443E-03-02-113-02), F1(TOM-808 × TOM-717), F1(TOM-808 × TOM-757), and F1(TOM-810 × TOM-717) were the most resistant to the mite, exhibiting higher female mortality, reduced oviposition, and no nymph emergence observed. The genotypes F1(TOM-808 × TOM-667), F1(TOM-808 × TOM-717), F1(TOM-810 × TOM-615), and several lines, which exhibited reduced oviposition and foliar damage. The results of the bioassays indicated that high acylsugar content reduced oviposition and foliar damage of the tested pests. The hybrid F1(TOM-808 × TOM-717) is the most promising at this stage of the breeding program, as it shows resistance to both tested pests.

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.

Predatory mites are important biological control agents of spider mites in various crops. Long-term mass rearing on alternative foods, such as plant pollen, may affect their predatory efficiency, but data on Euseius scutalis are scarce. Therefore, this study aimed to evaluate whether long-term rearing of E. scutalis on cattail pollen influences its functional response when fed on Tetranychus turkestani. Functional and numerical responses of the predatory mite E. scutalis reared on cattail (Typha latifolia) pollen over 30 generations on different densities (2, 4, 8, 16, 32, 64, and 128) of T. turkestani were evaluated. The results indicated a type II functional response for E. scutalis on T. turkestani in all generations (G1, G10, G20, and G30) tested. The attack rate (a) of E. scutalis increased as the number of generations increased. The handling time decreased as the number of generations increased from G1 (0.330 h) to G10 (0.318 h), then increased in G20 (0.572 h) and then decreased again in G30 (0.385 h). In G1 and G30, the number of eggs deposited by the predator increased as prey density increased. However, in G10 and G20, egg deposition increased up to 64 prey and then slightly decreased at 128 prey. The results indicated that the quality of E. scutalis did not lessen against T. turkestani after different periods of rearing on cattail pollen. Based on this study, we recommend cattail pollen as a good candidate for the large-scale rearing of E. scutalis for use in biological control programmes against T. turkestani.

Haritalodes derogata (Fabricius) (Lepidoptera: Crambidae), commonly known as the cotton leaf roller, is an important polyphagous pest that causes damage to various agricultural and forest plants, especially those of the Malvaceae family, but also to crops such as cotton, cashew, bamboo, oats, and jute. While microbial control agents are known for their efficacy and environmental friendliness, there are few studies demonstrating their effect on H. derogata. The aim of this study was to evaluate the bioefficacy of microbial agents from different pathogen groups against this pest. To this end, we investigated the insecticidal potential of fifteen indigenous microbial isolates from our entomopathogen collection. These included five Bacillus thuringiensis strains (Bn1, MnD, Mm2, Xd3, Lyd8), five entomopathogenic fungi (Metarhizium flavoviride As2, M. anisopliae KTU-51 and Beauveria bassiana Pa4, Pa5, Hp5), and five baculoviruses (HycuGV-Hc1, LdMNPV-T2, AcMNPV, DapuNPV-T1, SeMNPV-U), applied at concentrations of 1.8 × 109 cfu/mL, 1 × 107 conidia/mL, and 1 × 107 PIB/mL, respectively, against H. derogata larvae under laboratory conditions. Among these, B. thuringiensis subsp. kurstaki Bn1, B. bassiana Pa4, Hyphantria cunea granulovirus (HycuGV-Hc1), and Spodoptera exigua nucleopolyhedrovirus (SeMNPV-U) showed strong insecticidal activity and were selected for virulence assays, each achieving 100% mortality in third instar larvae. The median lethal concentrations (LC50) were determined to be 7.1 × 104 cfu/mL, 3.3 × 103 conidia/mL, 1.2 × 103 PIB/mL, and 1 × 103 PIB/mL, respectively. These results indicate that indigenous microbial agents are a promising environmentally friendly alternative to chemical pesticides in the control of H. derogata.

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 European red spider mite, Panonychus ulmi Koch (Acari: Tetranychidae), is a major mite pest affecting a wide range of crops globally. Its rapid development and extensive dispersal enable P. ulmi to form large colonies through arrhenotokous reproduction, which subsequently produces bisexual offspring following oedipal phase mating. In this study, life tables for arrhenotokous and bisexual P. ulmi populations were constructed and assessed using the age-stage two-sex life table theory. To assess whether maternal age affects the offspring sex ratio, 3D life table analysis was conducted for both groups. Population projection for P. ulmi bisexual and arrhenotokous was based on life table data to evaluate the effect of arrhenotokous reproduction on population growth. Bisexual population parameters were r = 0.1828 d−1, λ = 1.2006 d−1, R0 = 44.80 offspring, and T = 20.79 d. The theoretical calculation of these parameters cannot be performed solely based on the survival rate and female fecundity of the P. ulmi arrhenotokous population, as only male offspring were produced during the first seven days before the arrival of the bisexual population. Although arrhenotokous parthenogenesis yields fewer offspring than bisexual reproduction, it significantly influences population dynamics by enabling a single virgin female to establish a bisexual population. Controlling offspring sex ratios enables rapid population growth and colonisation of new habitats. A comprehensive understanding of arrhenotokous reproduction is crucial for developing effective management strategies for P. ulmi. Future research should integrate genomic, ecological, and evolutionary perspectives to bridge the gap between laboratory and field conditions.

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.