The growing use of pyrethroid insecticides raises concerns regarding their sub-lethal effects on beneficial non-target insects. This study evaluates the long-term neurophysiological and behavioural consequences of deltamethrin exposure through contaminated dung in the dung beetle Digitonthophagus gazella. Adult beetles were exposed to three sublethal concentrations of the LC50 (0.275 ppm): 1/20th (LD-0.014 ppm), 1/10th (MD-0.028 ppm) and 1/5th (HD-0.05 ppm), in comparison to control, for 10, 20 and 30 days. Results revealed a dose- and time-dependent decline in tunnelling activity and brood ball production. In comparison to controls, brood ball development decreased by up to 75% after 30 days at the highest dose (HD). Neurochemical investigations further demonstrated significantly (p < 0.01) reduced levels of dopamine (DA) (12%-26%), serotonin (5-HT) (8%-27%), acetylcholinesterase (AChE) activity (8%-40%) and nitric oxide (NO) levels (66%-85%), over the course of exposure. Neurotransmitter biosynthesis genes (ddc, 5-htpdc, chat, nos) and neuropeptide signalling genes (npf, npfr, it, itr, mip) were downregulated (2.5-9-fold) in conjunction with these neurochemical changes. The findings show that chronic sublethal exposure to deltamethrin is associated with altered neurochemical and transcriptional profiles and impaired nesting behaviour in D. gazella. These findings demonstrate the sensitivity of neuroendocrine pathways to pyrethroid exposure and emphasize the significance of assessing the effects of insecticides on ecologically beneficial insects.
Silk derived from the cocoon of the Bombyx mori (Linnaeus, 1758) plays an important role in the global economy. During the larval period, this insect feeds exclusively on mulberry leaves or on artificial diets that include mulberry leaves in their composition. Protein supplementation of silkworm diets has been explored as a strategy to optimize production performance. Silver nanoparticles (AgNPs) have been tested as a supplementation option, potentially stimulating insect feeding activity. This study's purpose was to analyse the effects of adding isolated and combined soy protein with silver nanoparticles incorporated on mulberry leaves during the B. mori feeding process. The group fed with AgNPs presented the highest body (5.29 g) and cocoon weight (2.19 g) among the groups tested. The group supplemented with silver nanoparticles and 2% isolated soy protein (S2Ag) exhibited a synergistic effect, resulting in lower leaf consumption, but with a silk conversion rate of 24.1%, similar to that of the control. These results are possibly related to differences in the expression of the silk genes fibroin and sericin. The AgNPs group showed higher expression of the heavy-chain fibroin (H-Fib) gene, and the S2Ag group showed higher expression of the sericin-1 and sericin-2 genes at the end of the 5th instar. These findings suggest potential practical applications of dietary supplementation with isolated soy protein and silver nanoparticles, both for larval development and for optimizing silk production, underscoring the importance of understanding the toxicological effects of these components in the context of sericulture.
Abstract The inability of black soldier fly larvae to efficiently extract and assimilate nutrients from diverse organic substrates leads to the production of small‐sized and poor‐quality larvae. Suboptimal nutrient digestion reduces overall biomass yield, survival and overall larval quality. Incorporating exogenous probiotics into black soldier fly larvae feeding systems is important in improving overall black soldier fly production. The study focused on the use of an exogenous Bacillus probiotic strain mixture to improve larval survival, growth and nutrient accumulation. A total of 1500 four‐day‐old black soldier larvae were manually counted in triplicate for each treatment and subjected to exogenous Bacillus probiotic strain mixture inoculation levels using a poultry feed. Four inoculation levels were used: P0 (0 colony‐forming unit [CFU]/kg) as a control, P1 (4 × 10 10 CFU/kg) as treatment 1, P2 (8 × 10 10 CFU/kg) as treatment 2 and P3 (12 × 10 10 CFU/kg) as treatment 3. The experiment was carried out in the laboratory under a completely randomised design. Larvae were reared under ambient conditions, with an average temperature of 28 ± 1.09°C and relative humidity of 70 ± 8.1%, using a poultry feed with a pH of 8.2 ± 1.0. Significant differences among inoculation levels for length, weight, survival and proximate composition were recorded ( p < 0.001). Significantly higher growth, survival rates and protein content were observed in larvae fed on P2‐inoculated feed ( p < 0.001). Findings of the present study demonstrate that exogenous Bacillus probiotic strain mixtures not only enhance larval growth but also survival rates and nutrient accumulation, thereby increasing overall production.
Abstract Microplastic (MP) contamination of soils is increasing, yet mechanistic evidence for mixture toxicity in terrestrial insects remains limited. We investigated the sub‐chronic (30‐day) dietary effects of polystyrene (PS‐MP), polyethylene terephthalate (PET‐MP) and their binary mixture (1% PS + 1% PET; total 2% w/w) on the ground beetle Blaps polychresta . Endpoints included defecation rate, digestive enzyme activities (amylase and protease), oxidative stress biomarkers (reactive oxygen species [ROS], catalase [CAT] and superoxide dismutase [SOD]) and histopathological alterations in the midgut and testis. Survival was unaffected; however, PS and PET individually reduced defecation rate, whereas the mixture did not further exacerbate gut motility impairment. All treatments significantly altered digestive physiology, with increased amylase and reduced protease activity and the strongest imbalance occurring in the mixture group. ROS levels were elevated in both midgut and testicular tissues, accompanied by significant upregulation of CAT and SOD, indicating oxidative stress–mediated responses. Histological investigation revealed epithelial disruption and muscle disorganization in the midgut and degeneration of testicular follicles, vacuolization, pyknosis of spermatocytes and reduced follicular integrity. Trypan blue staining confirmed increased cellular damage in the testes following MP exposure. Testicular follicle diameter decreased in PS‐ and PET‐exposed beetles, indicating impaired spermatogenesis. Overall, chronic ingestion of PS and PET disrupts digestive and male reproductive physiology through oxidative stress–linked mechanisms, with mixture exposure intensifying several biochemical and histopathological effects. These findings highlight the importance of incorporating polymer interactions into terrestrial insect risk assessments.
Bumble bees' (Bombus spp.) thoracic muscles can generate substantial heat through non-flight thermogenesis (NFT) to mediate flight under cool conditions and incubate brood. Bumble bee castes vary tremendously in life history, physiology and body size, making them an excellent system to investigate sources of intraspecific variation in NFT. This study measured trends in NFT-mediated rewarming across castes (queens, workers and males) of a bumble bee species (Bombus impatiens), while investigating the effects of body mass and seasonality. We used a thermal imaging camera to quantify changes in thoracic temperature as bees recovered from chill coma and used generalized additive models to compare rewarming curves across groups. All bees showed two distinct phases of rewarming, which we suggest represent passive and active warming, driven by biophysical heat exchange and physiological thermogenesis, respectively. While all castes reached similar equilibrium temperatures, each showed significantly different rewarming patterns. Mass effects were most pronounced for males, with small males (<0.15 g) failing to achieve above-ambient body temperatures. In addition, fall queens reached higher thoracic temperatures than spring queens, suggesting NFT may also vary seasonally. The adaptive significance of this variation requires further exploration, but our data demonstrate heretofore unknown individual variation and size-related constraints in thermal physiology in bumble bees.
Harmonia axyridis Pallas is an important predatory insect in biological control. Understanding the relationship between the flight performance and energy metabolism of H. axyridis can optimize its field release strategies and enhance the efficiency of biological control. This study analysed the differences in flight ability, energy metabolic substances and the expression of genes related to these traits under different flight durations between male and female individuals of native H. axyridis using tethered flight assays. Results showed that the pre-flight body weight, reserves of triglycerides and three types of carbohydrates in female individuals were significantly higher than those in males. The long-duration and long-distance flight ability of females was also superior to that of males. In addition, based on gene expression results, it was inferred that in terms of energy metabolism, females primarily consumed glycogen and trehalose for energy during the early flight phase and compensated with minor triglyceride mobilization in the later phase. In contrast, males enhanced trehalose levels through glycolipid conversion to maintain energy supply during the mid-to-late flight phases. At the same time, two trehalase activities and related gene expressions indicated that males may primarily rely on increasing soluble trehalase activity to promote trehalose decomposition, while females may mainly depend on membrane-bound trehalase. In summary, our results indicate that the flight energy metabolism of H. axyridis may follow a 'carbohydrate-first, lipid-subsequent' pattern. Females performed better in long-duration and long-distance flights due to higher initial energy reserves, while males narrowed the later gap through lipid metabolism mobilization. The study not only fills the research gap in the coupling mechanism between flight and metabolism of the H. axyridis but also provides an important theoretical basis for its application and strategy optimization in biological control.
Colour variation of lepidopteran pupae commonly involves green and brown phenotypes, with green being more common in direct-developing generations, and brown predominating in diapausing generations. Most research on these phenotypes has focused on benefits in predation avoidance, where green pupae are better camouflaged during summer and brown pupae during winter. Interestingly, in some butterflies, a large proportion of individuals can show the colour morph not expected for that generation, suggesting that pupal colour may have benefits beyond crypsis. Little work has focused on the differences that occur during diapause and post-diapause development. We investigated metabolic differences and potential thermoregulatory effects between brown and green colour morphs in diapausing pupae of the butterfly Papilo machaon. We measured metabolic rate-temperature relationships during diapause and post-diapause development under full-spectrum light to see if brown absorb more thermal radiation. Additionally, we measured eclosion success as a function of colour and metabolic rate. Brown pupae showed no thermoregulatory benefits in developmental time under light exposure. However, during diapause, they had lower metabolic rates across temperatures compared to green pupae. Eclosion success and timing did not differ between morphs, but individuals with high diapause metabolic rates had a low probability of successful eclosion. These findings suggest that the higher prevalence of brown pupae in the diapausing generation maybe associated with lower diapause metabolic rates, which may confer an adaptive advantage in the form of a higher probability of successful spring eclosion. Although this study cannot mechanistically link pupal colour to winter performance, it suggests colour has fitness relevance during winter and warrants further investigation.
Reproduction and immunity are essential biological processes that compete for resources and energy. In insects, trade-offs between immunity and reproduction are often explored before female oviposition. However, the impact of egg laying on immune parameters remains poorly explored. Here, we address this knowledge gap in the European earwig, an insect with extensive maternal care, by comparing immune parameters at different stages of egg production. We examined both the basal immune levels and induced immune responses in 150 females (75 that laid eggs and were providing care and 75 same-aged females that had not yet laid eggs) by injecting them with heat-killed Serratia marcescens bacteria and measuring humoral (phenoloxidase activity) and cellular immune responses. The cellular immune response focused on granulocytes, plasmatocytes and spherulocytes, which we morphologically identified using four microscopy techniques. Our results show that females that had produced and cared for eggs exhibited a lower total haemocyte count and a reduced proportion of plasmatocytes but a higher proportion of spherulocytes. In contrast, having produced and cared for eggs had no effect on phenoloxidase activity or the proportion of granulocytes. Interestingly, neither the immune challenge nor female size influenced immune traits alone or in interaction with egg presence. Overall, our findings revealed that oviposition and post-oviposition maternal investment induce shifts in the composition of immune cell populations. This underscored the importance of oviposition and parental care in shaping the immune response in insect mothers and calls for further research into the specific functions of haemocytes in Dermaptera and the evolutionary implications of these investments for life history traits association.
The insect cuticle is a dynamic physiological interface that integrates structural and chemical traits to mediate interactions with the environment. In the polyphagous whitefly Aleurodicus dispersus, reproduction involves the deposition of eggs in wax-embedded spirals, yet the physiological coordination of these surface traits across life-history transitions remains poorly understood. This study integrates developmental morphometrics, host-resolved behavioural assays and gas-chromatographic profiling of cuticular hydrocarbons (CHCs) to examine the functional organisation of the A. dispersus surface. Morphometric analysis revealed pronounced sexual dimorphism and directional asymmetry in sensory and flight structures, with large effect sizes supporting these differences, reflecting sex-specific physiological investment in dispersal versus fecundity. Oviposition geometry exhibited significant behavioural plasticity, with regular spiral formation declining sharply as a function of infestation age and host-plant identity, including the occurrence of fragmented and overlapping spiral patterns at later infestation stages. CHC profiles, identified primarily based on retention time comparison with n-alkane standards (C8-C30) and extrapolated retention patterns for longer chains (e.g., C32-C36), demonstrated clear developmental structuring, with compound assignments considered putative in the absence of GC-MS confirmation. Mobile feeding stages and adults were dominated by short-chain hydrocarbons (C8-C10), while immobile eggs and pupae selectively accumulated long-chain compounds (C27-C36). Multivariate analyses confirmed a clear chemical separation between life stages based on mobility, indicating systematic developmental reorganisation of surface chemistry. The observed association between hydrocarbon chain length and inferred barrier properties is consistent with established physicochemical principles rather than directly measured functional outcomes, and functional implications should be interpreted cautiously in the absence of direct permeability or water-loss measurements. These findings provide a physiological framework for understanding how invasive generalist insects may modulate their external interface to support shifting reproductive and survival requirements across the life cycle.
Oxidative stress (OX) is a state of imbalance between antioxidants and reactive oxygen species, which are the byproducts of oxidative phosphorylation in the mitochondria. Honey bees (Apis mellifera) and small carpenter bees (Ceratina calcarata) are two important pollinators. However, it is unclear how pollinators respond to the abiotic stress in different landscapes at different management levels. Conventional, organic and roadside use different pesticides and pest control management practices. The roadside landscape habitats are unmanaged systems with potentially minimum exposure to agrochemicals and high traffic-related pollutants. Conventional farms represent direct agrochemical inputs, and organic farms restrict synthetic pesticide usage. Oxidative stress as levels of lipid peroxidation and protein carbonylation was quantified in individual bees of adult and larval stages and among three landscapes. Furthermore, pesticide residues were determined using chromatographic analysis. Results from the lipid assay show that bees collected from organic and roadside landscapes exhibited the lowest and highest OX levels, respectively. The protein carbonylation assay indicated a significant difference between conventional and organic farms. Similarly, a greater number of pesticides were detected in conventional farms compared to other habitats. Overall, these findings show that variation in pesticide residue profiles across landscapes is associated with different OX responses in bees, which will be a valuable foundation for monitoring pollinator health across different landscapes. It also showed that small carpenter bee is an emerging model system to study OX and insect physiology.
Cuticular waxes are complex mixtures of hydrocarbons and other lipophilic compounds that form an outer protective layer over the insect cuticle, playing a role in ecological interactions as well as physiological processes. While the composition of cuticular hydrocarbons (CHCs) is largely genetically determined, several studies have linked diet to CHCs, and limited research indicates a potential influence of dietary fatty acids. Considering this, the current work investigates the effect of nine cereal flours, that is, wheat, rice, maize, barley, oat, ragi, sorghum, soybean and gram, each with a distinct fatty acid composition, on the cuticular wax profile of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae), a globally significant stored grain insect. Fatty acid compositions of the nine flours and the cuticular waxes from the beetle populations reared on each diet were characterized using gas chromatography mass spectrometry (GC-MS). In all the beetle populations, the most abundant compound was 1-pentadecene, followed by cis-9-tetradecen-1-ol and 1-heptadecene, irrespective of the diet. While no qualitative differences in cuticular wax composition were found, significant quantitative variation in cuticular wax profile was observed across dietary groups. Similarity percentage (SIMPER) analysis revealed a cumulative Bray-Curtis dissimilarity of 47.72% among the flour samples based on their fatty acid profiles, and a dissimilarity of 18.51% among T. castaneum populations reared on these flours based on their cuticular wax composition. Non-metric multidimensional scaling (NMDS) further indicated substantial variation in the cuticular wax profiles of beetle populations raised on different dietary sources. Pearson's correlation analysis between the concentrations of individual cuticular wax components and the fatty acid content of the respective diets demonstrated strong correlations between specific cuticular compounds and dietary fatty acids. Notably, levels of 1-pentadecene in the beetle cuticle were strongly associated with the concentrations of hexadecanoic and octadecanoic acids in the flours. These results support the hypothesis that, alongside endogenous conserved biosynthetic pathways, dietary fatty acid composition contributes to the modulation of insect cuticular chemistry. This dietary influence may have important implications for understanding insect ecological plasticity and diet-mediated changes in surface chemistry.
The inability of black soldier fly larvae to efficiently extract and assimilate nutrients from diverse organic substrates leads to the production of small-sized and poor-quality larvae. Suboptimal nutrient digestion reduces overall biomass yield, survival and overall larval quality. Incorporating exogenous probiotics into black soldier fly larvae feeding systems is important in improving overall black soldier fly production. The study focused on the use of an exogenous Bacillus probiotic strain mixture to improve larval survival, growth and nutrient accumulation. A total of 1500 four-day-old black soldier larvae were manually counted in triplicate for each treatment and subjected to exogenous Bacillus probiotic strain mixture inoculation levels using a poultry feed. Four inoculation levels were used: P0 (0 colony-forming unit [CFU]/kg) as a control, P1 (4 & times; 10(10) CFU/kg) as treatment 1, P2 (8 & times; 10(10) CFU/kg) as treatment 2 and P3 (12 & times; 10(10) CFU/kg) as treatment 3. The experiment was carried out in the laboratory under a completely randomised design. Larvae were reared under ambient conditions, with an average temperature of 28 +/- 1.09 degrees C and relative humidity of 70 +/- 8.1%, using a poultry feed with a pH of 8.2 +/- 1.0. Significant differences among inoculation levels for length, weight, survival and proximate composition were recorded (p < 0.001). Significantly higher growth, survival rates and protein content were observed in larvae fed on P2-inoculated feed (p < 0.001). Findings of the present study demonstrate that exogenous Bacillus probiotic strain mixtures not only enhance larval growth but also survival rates and nutrient accumulation, thereby increasing overall production.
Interactions among conspecific insects generate social cues that can influence development and reproductive physiology. Larval crowding is common in insects, including ladybird beetles, yet its effects on reproductive traits under abundant food conditions remain poorly understood. However, separating the effects of crowding itself from those of food limitation remains challenging, as these factors often co-occur in natural and laboratory settings. In this study, we examined how larval crowding affects growth and reproductive physiology in the ladybird beetle Cheilomenes sexmaculata (Fabricius) under laboratory conditions with ad libitum food supply. We hypothesized that larval crowding would negatively influence growth and reproductive investment despite food limitations. Larvae from an experimental stock were reared either singly (control) or under crowded conditions (six larvae per Petri dish). Development time, body weight, gonadosomatic index (GSI) and gonadal traits (weight, area and number of testicular lobules/ovarioles) were measured. Larval crowding significantly increased development duration and body weight in both sexes. Crowded individuals also exhibited larger gonads, accompanied by sex-specific changes in reproductive allocation: Males showed reduced GSI, whereas females showed increased GSI. Such differences suggest that early crowding has lasting effects on how reproductive traits develop. Examination of gonadal morphology showed that beetles reared under crowded conditions developed fewer but larger testicular lobules and ovarioles. Overall, these results demonstrate that larval crowding alone, independent of food limitation, influences growth and gonadal development in a sex-specific manner. The study highlights density as an important developmental factor shaping reproductive physiology in ladybird beetles.
The Asian tiger mosquito Aedes (Stegomyia) albopictus (Diptera: Culicidae) is found in peri-urban environments and transmits pathogenetic arboviruses such as Zika, chikungunya and dengue. It is anthropophilic and feeds during the day. The blood is necessary for egg production. The purpose of the present paper was to study the effect of mating on the lifespan of adults (males and females) of Ae. albopictus as well as the effect of blood meal frequency (zero, one and two meals) on the biodemographic characteristics: lifespan, egg production, number of pupae, pupation percentage, number of male offsprings, number of female offsprings, ratio of male/female offsprings. The population was collected at the vicinity of Volos and Larissa, Thessaly, Greece and the experiments were conducted under controlled laboratory conditions. Lifespan did not differ between unmated and mated males and females. The number of blood meals (one and two) significantly reduced adult lifespan compared with those with no blood meal. The second blood meal doubled egg production. The knowledge of the biology of mosquitoes and especially the effect of blood meal provides valuable information for the development of mosquito population models and effective mosquito control programmes.
The rising demand for sustainable pest management has increased interest in plant-derived biopesticides as environmentally friendly alternatives to synthetic insecticides. This research assessed the insecticidal potential of Melia azedarach leaf extract (MLE) against Galleria mellonella larvae through comprehensive phytochemical, toxicological and physiological analyses. Phytochemical screening indicated substantial polyphenolic content with total phenolic (42.06 +/- 1.12 mg GAE/g), flavonoid (16.96 +/- 1.42 mg QE/g) and condensed tannin (9.46 +/- 0.49 mg CE/g) contents. High-performance liquid chromatography (HPLC) analysis detected 16 phenolic and flavonoid substances, with kaempferol and quercetin as major constituents. Acute toxicity assessment via ingestion demonstrated dose-dependent mortality with an LD50/10 days of 1.39 mg g-1 body weight. Sublethal exposure (LD25) markedly disrupted developmental parameters, prolonging larval and pupal development and diminishing pupal weight and fecundity. All investigated midgut enzymes showed significant activity decline, with lysozyme exhibiting the most pronounced reduction (68.13%); carbohydrate digestive enzyme activity (alpha-amylase, alpha-glucosidase, beta-glucosidase, beta-galactosidase) reduced in the range of 42%-60%, while protein digestive enzyme activity (trypsin, chymotrypsin, carboxypeptidase, cysteine protease, leucine aminopeptidase) reduction was in the range of 34%-53%. Histological and ultrastructural analyses demonstrated extensive midgut epithelial damage, including vacuolization, cellular degeneration and microvilli disruption. Thus, M. azedarach seems to possess a battery of insecticidal mechanisms that establish it as an eco-friendly biocontrol agent under integrated pest management strategies.
This study aims to elucidate how temperature and photoperiod interact across the annual lifecycle of the wild mulberry silkmoth, Bombyx mandarina (Moore) (Lepidoptera: Bombycidae), to determine the timing of generations and geographic variation in voltinism. We investigated the seasonal prevalence of B. mandarina across eight regions in Japan with a broad latitudinal and altitudinal range. Two peaks of occurrence were observed in cooler areas, while three peaks were found in warmer areas. The timing of the first occurrence was closely associated with spring temperature, leading to delayed emergence in cooler areas. Given that B. mandarina lays diapause eggs when exposed to short daylength conditions during the larval stage, the occurrence of a third generation depends on whether second-generation larvae encounter daylengths longer than the critical threshold for diapause induction. In warmer regions, this condition was fulfilled, allowing a third generation to occur; in cooler regions, diapause induction in the second generation prevented further development. Our extensive field observations demonstrate that voltinism in B. mandarina is determined by the combination of spring temperature, which governs the timing of the first-generation occurrence, and autumn daylength, which determines the egg diapause and termination of annual life cycle.
Human-generated traffic noise can increase stress levels in wild animals, which may underlie fitness declines. And prior exposure to noise may influence an individual's response. While much research has examined noise-induced stress on vertebrates, much less is known regarding invertebrates. We tested the hypothesis that traffic noise affects spider stress. To accomplish this, we measured heart rate elevations in two orb-weaving Trichonephila spiders in the United States, the non-native jor & omacr; spider (Trichonephila clavata) and the golden silk spider (Trichonephila clavipes). Mature females were captured along roads at natural areas with either prior exposure to loud noise with high daily traffic patterns or quiet sites with low daily traffic patterns and housed in clear containers in a lab. For traffic noise playbacks, we broadcast a simulated pink noise signal at captive spiders and monitored their heart rate via contractions of the dorsal vessel, which we monitored remotely by a high-magnification video. Jor & omacr; spiders with prior exposure to loud traffic had the largest increase in heart rate. In contrast, the magnitude of heart rate change for golden silk spiders was predicted by baseline heart rates, regardless of prior noise exposure. Despite the change in heart rate, for both species, observed elevations following exposure to traffic noise were less than that observed when they were subjected to severe stress. Thus, our research adds to a growing body of literature that shows orb-weaving Trichonephila spiders tend to be resilient to anthropogenic disturbance, and their mild stress responses may underlie their ability to cope with human-generated environmental change.
The mulberry pyralid moth, Glyphodes pyloalis (Lepidoptera: Crambidae) (Walker 1859), is considered a key pest of mulberry trees, which are exclusively used for silkworm rearing. Considering that silkworm cultivation is dependent on mulberry leaves, it is inevitable to choose a suitable control method against mulberry pyralid moths. In recent years, research about pheromones in insects and how they affect the intraspecies and interspecies relationships has received much attention. These studies have included the identification of pheromone compounds and their biosynthesis, recognition of pheromone receptors in insects, as well as behaviors caused by receiving pheromones in insects in order to be used in pest control programmes. Considering that sex pheromones are non-toxic and specific compounds, the present study was conducted to identify pheromone compounds in G. pyloalis. Three compounds included hexadecanoic acid methyl ester (H), (Z)-9-octadecenoic acid methyl ester (S) and octadecanoic acid methyl ester (O) were identified and introduced as pheromone compounds in G. pyloalis. Examining the results of the wind tunnel showed that these compounds in the ratio of 8H:4S:1O show the best attraction in the male population. However, this ratio of compounds when used in pheromone traps in mulberry orchards was found to be less effective than control traps (non-mated females). It seems that this decrease in performance happened due to the rapid decomposition of the compounds in the environment. According to the results of the present study, it can be said that identifying the sex pheromone of G. pyloalis can lead to the development of efficient strategies for monitoring and controlling the population of this pest.
Insects represent an enormous group of organisms with an extraordinary array of identified species, and others yet to be identified, habiting the most diverse regions. Likewise, insects present different behaviours depending on their needs, adapting their life cycles. An example is gregariousness, an aggregation behaviour common, but not limited, to social insects. One reported mechanism that underlies gregarious behaviour is growth promotion, especially among insect larvae. In this study, waxworms of Galleria mellonella (Lepidoptera: Pyralidae), a worldwide distributed moth, were used due to their gregarious behaviour. An exploratory RNA-seq approach was performed in order to identify transcriptional responses upon gregariousness. Results indicate upregulation of a greater number of genes when they are gregarious compared with individualized waxworms. Enrichment analysis suggests distribution of genes across biosynthesis of amino acids and carbon metabolism pathways with high significance. Key differentially expressed genes, such as a general odorant-binding protein 2, might indicate specific roles for gregariousness in lepidopterans. This study deepened our understanding of genes involved in waxworms aggregation, with potential targets in metabolism, defence and/or communication.
The extensive use of conventional insecticides for pest management has raised concerns due to their adverse effects on non-target organisms, environmental persistence and health risks to mammals. Identifying alternative control agents with lower ecological impact has therefore become a priority. In this study, the ecotoxicological effects of streptomycin, an aminoglycoside antibiotic with low mammalian toxicity, were evaluated in larvae of Cydia pomonella, a major agricultural pest. Biochemical assays revealed significant increases in the activities of transferase enzymes (AST, ALT, GGT) and metabolic enzymes (LDH, ALP, CK, AMYL) following streptomycin exposure, indicating cellular damage and disruption of energy metabolism. Moreover, non-enzymatic antioxidant levels were significantly altered. Albumin and bilirubin-related tetrapyrrole levels increased, whereas uric acid decreased. These findings demonstrate that streptomycin interferes with both metabolic and antioxidant defence systems in C. pomonella. While streptomycin shows potential as a chemical tool for codling moth control, its broader ecological consequences must be considered before large-scale application.
