Insects最新文献

Spodoptera frugiperda (fall armyworm, FAW) has rapidly spread across Asia and Africa in recent years, with its seasonal long-distance migration ability serving as the biological basis driving its region-wide outbreaks. Although the migratory biology of FAW has been extensively studied, it remains unclear whether there is stable differentiation between migratory and non-migratory individuals. In this study, we revealed the significant differences in morphological parameters between migratory populations and laboratory-reared populations. The migratory populations exhibited a greater body length and width and forewing size, as well as a lower body weight, compared to the laboratory colony. After three generations of indoor rearing, the migrants' morphology and flight capacity converged to the laboratory phenotype, indicating the existence of a migratory ecotype in FAW. Through further investigation, a method for identifying the migratory ecotype of FAW was proposed based on the corrected wing loading (WL) and forewing aspect ratio (FA), which was successfully applied to distinguish individuals of the migratory ecotype in field populations. Our results confirm that FAWs exhibit stable differentiation into a migratory ecotype, and using WL and FA provides a robust, field-deployable tool for regional FAW monitoring, early warning systems, and targeted FAW control.

Mosquito-borne diseases, including dengue fever, chikungunya, and Zika, continue to pose a substantial global public health challenge. This is largely attributable to the absence of effective vaccines and the expanding distribution of vectors such as Aedes albopictus (Ae. albopictus). Repellents, therefore, remain a critical component of prevention strategies for disease prevention. However, existing formulations have notable limitations. Synthetic repellents such as DEET provide broad-spectrum efficacy but may raise safety concerns, especially at high concentrations. In contrast, botanical repellents, such as citronella and camphor oils, offer more favorable safety profiles but are restricted by short protection durations due to their high volatility. To overcome these drawbacks, this research developed a composite mosquito repellent through the strategic combination of DEET (5-15%), citronella oil (10-20%), and camphor oil (5-15%). This formulation leverages interactions across multiple olfactory pathways to simultaneously enhance efficacy and reduce the DEET concentration. Orthogonal experimental optimization identified an optimized formulation, Mix-3 (consisting of 15% DEET, 15% citronella oil, and 10% camphor oil in 75% ethanol), which achieved a mean complete protection time of 9.45 h. Mix-3 provided longer protection than 7% DEET (mean difference = 5.50 h, p < 0.001), 4.5% IR3535 (2.83 h, p < 0.001), 10% citronella oil (3.58 h, p < 0.001), and 15% DEET (6.50 h, p < 0.001). Catnip oil did not contribute significantly to repellency (p = 0.895). This study demonstrates that the rational combination of synthetic and botanical repellents effectively overcomes the limitations of single-agent formulations, providing a long-lasting and scalable approach for vector control.

T. remus is an important egg parasitoid of S. frugiperda, serving as a significant role in its biological control. This study systematically examined the host discrimination behavior of T. remus. The parasitic process comprises several distinct behavioral stages: host searching, antennal tapping and examination, ovipositor probing, "8"-shaped marking, and grooming. Following successful oviposition, females perform a characteristic "8"-shaped marking on the host egg surface with their ovipositor, which deters conspecific females from parasitizing the same host. T. remus exhibited a pronounced ability to discriminate parasitized hosts, utilizing both antennae and ovipositor to avoid superparasitism. As host density increased, the searching time of T. remus decreased while the parasitism rate increased, eventually stabilizing. Parasitic discrimination was significantly influenced by oviposition experience: experienced females effectively recognized marked host eggs across a temperature range of 16 to 36 °C and time intervals of 0 to 12 h post oviposition. In contrast, naive females exhibited discrimination ability only at lower temperature (16 °C) and immediately following oviposition (0 h). These findings deepen the understanding of the behavioral ecology of T. remus and provide a crucial theoretical basis for its efficient application in the biological control of S. frugiperda.

Hermit beetles (Osmoderma spp.) are protected and endangered across Europe, experiencing ongoing decline throughout most of their range. Because nearly all populations are small and isolated, Osmoderma genus is highly susceptible to extinction and requires active conservation measures. The primary cause of decline in the genus is habitat loss, particularly the removal of hollow trees that provide essential larval habitat. The nutritional wood mold within these hollows, on which larvae depend for 3-4 years of development, is directly linked to population survival. The aim of this study was to develop methodical ex situ breeding guidelines for reintroduction designed to eliminate environmental constraints and ecological requirement gaps. We first synthesize literature-based evidence on habitat conditions, applied methods, study durations, and key ecological insights relevant to Osmoderma conservation. Based on these results, we then create an ex situ breeding guideline for reintroduction, combining published data with practical breeding objectives in cases where empirical data are limited.

The region of South-East Europe, located in geologically and climatically diverse areas, hosts a wide range of freshwater habitats. However, comprehensive studies of macroinvertebrate communities are limited, and research on Chironomidae (Diptera) is particularly scarce. We present data on the diversity and structure of chironomid assemblages in hilly and mountainous streams across three ecoregions: the Pannonian Lowland (Ecoregion 11), the Dinaric Western Balkans (Ecoregion 5), and the Eastern Balkans (Ecoregion 7) and provide a comparative overview of their community patterns based on 130 samples. According to the CCA results and Monte Carlo permutation tests, water temperature, dissolved oxygen, conductivity, pH, and altitude were identified as statistically significant parameters influencing Chironomidae assemblages across the ecoregions, collectively explaining 72.20% of the variation. The higher diversity indices were recorded in each season in the Pannonian Lowland and the highest within-ecoregion similarity. Dissimilarity was highest between ER11 and ER7 and lowest between ER5 and ER7. These results demonstrate that the ecoregion was the strongest influence of the studied environmental variables on Chironomidae assemblages, with community patterns closely reflecting their spatial distribution across distinct ecoregional settings.

Fecal retention is a distinctive reproductive strategy in certain leaf beetles, which enables females to use accumulated fecal material to protect their eggs and enhance offspring survival. The adult flea beetle Asiophrida xanthospilota (Baly, 1881) is a specialist herbivore that feeds on the leaves of Cotinus coggygria Scop. (Anacardiaceae). Using light microscopy, scanning electron microscopy, and micro-computed tomography, we described and illustrated the hindgut anatomy of adult female A. xanthospilota during the pre-mated and post-mated reproductive phases. We further examined the physiological changes in the hindgut associated with fecal retention, and assessed hindgut muscle activity across these two reproductive stages. The hindgut of adult A. xanthospilota consists of three regions: ileum, colon, and rectum. The ileum is a thin, straight or coiled, tube enclosed by malpighian tubules and supported by circular and longitudinal muscles. The colon lies between the ileum and rectum, possesses a chitinized cuticle, and is externally covered with tracheae and tracheoles. A rectal valve separates the colon from the rectum, which forms the posterior end of the alimentary canal and is characterized by intimal spines and robust circular muscles. During the post-mated phase, fecal retention causes pronounced dilation of the hindgut, substantially increasing the volume occupied by food remnants. Electromyographic recordings revealed high hindgut muscle activity in pre-mated females, characterized by short and variable bursts, whereas post-mated females exhibited reduced activity with longer and more sustained bursts. The functional implications of these specialized structural features are discussed. Overall, these morphological and physiological adaptations enhance the fecal retention strategy by increasing fecal capacity, regulating hindgut motility, and enabling the formation of a protective fecal case around the egg mass.

This study characterizes the chemical defense system of the invasive longhorn beetle Aromia bungii, a destructive pest of Prunus trees, addressing the limited understanding of chemical defensive mechanisms in Cerambycidae. High-speed cameras, environmental scanning electron microscopy (ESEM), dissection, and micro-CT imaging were used to investigate defensive behavior, and the structure of the defense system, in this beetle. Both sexes of A. bungii possess a pair of triangular, sac-like defensive glands symmetrically located in the metathorax, attached to the metasternum. Upon mechanical stimulation, white liquid defensive substances are rapidly ejected through a pair of slit-shaped openings (~200 µm) at the metasternum corners, without gland eversion, reaching over 50 cm. The average weight of substances ejected in first sprays was 7.95 ± 0.79 mg for females and 8.62 ± 2.13 mg for males (mean ± se), with no significant difference between sexes. However, the weight in second sprays after 10 days was significantly lower, at 2.93 ± 0.54 mg for females and 2.22 ± 0.40 mg for males (mean ± se), suggesting that the beetles cannot re-synthesize the substances soon after spray. The weight of ejected substances had no correlation with beetle body weight. Our findings represent the first detailed morphological and functional description of a chemical defense system in Cerambycidae, revealing a specialized metasternal gland and spray mechanism. The substantial but likely non-renewable defensive substances reflect an adaptive trade-off in energy allocation between reproduction and defense in this species that exhibits high fecundity but a short lifespan at the adult stage.

Mangrove ecosystems along the Pacific coast of Panama are increasingly exposed to anthropogenic pressures such as urban expansion and deforestation. These habitats provide resources for orchid bees (tribe Euglossini), yet information on their assemblages in mangrove environments remains limited. In this study, we documented the diversity and composition of orchid bee communities in mangrove-forest edges from two coastal areas with contrasting levels of human disturbance: Panama Bay and Chame Bay. Orchid bee sampling was carried out during two independent periods: from April to July 2022 at three sites in Panama Bay, and from December 2022 to January 2023 at one site in Panama Bay and one site in Chame Bay, using McPhail traps baited with eucalyptus oil and distributed across multiple zones within each site. A total of 427 individuals representing 14 species and three genera were recorded. Observed species richness and abundance were lower at the more urbanized mangrove sites, where collections were dominated by a few widespread species, particularly Eulaema nigrita. Multivariate analyses revealed differences in community composition between sites. These patterns suggest associations between anthropogenic context and orchid bee assemblage structure in mangrove edges, although longer-term and multi-method studies are required to evaluate temporal consistency and underlying mechanisms. This study provides baseline information to support future monitoring of orchid bee communities in tropical coastal ecosystems.

Postharvest losses caused by potato tuber moths severely impact storage in the Andean highlands, where reliance on synthetic insecticides poses sustainability and safety concerns. This study evaluated eco-friendly alternatives for protecting stored seed tubers of the widely adopted cultivar INIA 302 Amarilis in Cajamarca, Peru. In two storage facilities, a completely randomized block design compared four treatments: Bacillus thuringiensis plus talc (Bt-talc), talc, agricultural lime, and wood ash against an untreated control. Powders were applied at 50 g per 10 kg of tubers, and incidence, severity of damage, and live larvae were assessed over 150 days. Bt-talc consistently achieved the lowest damage. Incidence in Cochapampa was 16.8% ± 6.2 with Bt-talc, compared with 58.1% ± 3.9 in the control; in Sulluscocha, incidence was 25.5% ± 4.8 and 64.2% ± 3.0 for Bt-talc and the control, respectively. A similar pattern was observed for moth-damage severity in both localities. Live larvae per unit were also markedly lower with 1.3 ± 0.3 (Cochapampa) and 1.6 ± 0.6 (Sulluscocha) under Bt-talc. A single dusting with Bt-talc, or alternatively agricultural lime, offers effective, accessible, and sustainable control of potato tuber moths in high-Andean storage.

The Chinese pepper buprestid beetle, Agrilus zanthoxylumi Li Meng Lou, 1989 (Coleoptera: Buprestidae), is a major trunk-boring pest affecting the yield and quality of Zanthoxylum bungeanum. Clarifying its feeding preferences among different pepper varieties and their associations with host-derived volatiles is important for understanding and improving effective management strategies. This study conducted feeding tests under no-choice and dual-choice conditions to evaluate the beetle's feeding preferences among three Z. bungeanum varieties-Fugu, Dahongpao, and Feng. Gas chromatography-mass spectrometry (GC-MS) was employed to analyze leaf volatiles, with factor analysis and partial least squares discriminant analysis (PLS-DA) used to identify key volatiles. Results showed that A. zanthoxylumi exhibited the highest resting frequency and feeding amount on Z. bungeanum Fugu leaves, with the lowest on Z. bungeanum Dahongpao leaves. Significant differences in unique volatiles were observed among the three varieties. Z. bungeanum Fugu contained 17 unique components, including (E)-4-hexen-1-ol, (-)-limonene, and (-)-α-pinene, with significantly higher quantities than Z. bungeanum Dahongpao and bungeanum Feng. Multivariate analyses further revealed distinct distributions in volatiles, with γ-terpinene, α-terpineol, and linalyl acetate emerging as key compounds distinguishing varieties. These results indicate that the feeding preferences of A. zanthoxylumi are closely related to host volatiles, suggesting variety-specific compounds may serve as primary chemical cues driving its preferences.