Journal of Insect Science最新文献

Aprostocetus hagenowii (Ratzburg) is a generalist parasitoid of cockroach (Blattodea) oothecae. Previous studies examining the host range of A. hagenowii have largely focused on cockroaches of economic and medical importance, which represent a minority of species in an order filled with species of diverse morphology, behavior, and ecology. The aim of this study was to expand the known host range of A. hagenowii with emphasis on nonpest as well as pest species from 3 cockroach families (Blattidae, Corydiidae, and Ectobiidae). Previously recorded host species were also reexamined. Oothecae from 17 cockroach species were exposed to A. hagenowii. Three new host species were recorded: Blatta lateralis (Walker) (Blattidae), Neostylopyga propinqua (Shelford) (Blattidae), and Parcoblatta fulvescens (Saussure and Zehntner) (Ectobiidae). Among the reexamined host species Periplaneta australasiae (Fab.) (Blattidae), Blatta orientalis L. (Blattidae), and Neostylopyga rhombifolia (Stoll) (Blattidae) were successfully parasitized. The cuticle thicknesses of 7 cockroach species' oothecae were also investigated. There were significant differences [Kruskal-Wallis: each zone (below keel, side, and bottom) measured P < 0.001] in cuticle thickness among the species measured. Polyphaga sassurei (Dohrn) (Corydiidae) and Eurycotis floridana (Walker) (Blattidae) had the thickest cuticles (each zone >0.09 mm) and Blattella germanica (L.) (Ectobiidae) had the thinnest (each zone <0.03 mm). However, the mean A. hagenowii ovipositor length (0.92 mm ± 0.01 mm) far exceeded the thickest oothecae measured. Oothecal cuticle thickness alone was not observed to determine the host suitability of each tested cockroach species for A. hagenowii.

Unraveling the numerous factors that drive phenotypic variation in trait expression among animals has long presented a significant challenge. Whereas traits like growth and adult size are often heritable and are passed on from one generation to the next, these can be significantly affected by the quality and quantity of resources provided by one or both parents to their offspring. In many vertebrates, such as birds and mammals, parents raise their young until adult, providing food, shelter, and protection. On the other hand, in insects, there is often little or no parental care, and the young are left to fend for themselves. Despite that, some insects can enhance the growth of their offspring. In parasitoid wasps, for example, mothers inject biochemical factors, including venoms, teratocytes, and virus-like particles into the host that increase host quality by regulating the nutritional milieu. However, it is not known whether maternal size is positively correlated with host regulation. Here, we evaluate maternal and host size-related effects on the development of an asexually reproducing (= female only) secondary idiobiont ectoparasitoid, Gelis agilis on pre-pupae in cocoons of its host, the primary parasitoid, Cotesia glomerata. Females G. agilis from 2 adult size classes, "small" (mean 0.7 mg) or "large" (mean 1.2 mg), were allowed to parasitize cocoons of differing size along a continuum from ~1.2 mg to ~4.0 mg, and the body size and development time of their offspring were measured. In both body size classes of G. agilis mothers, there was a strong correlation between host size and offspring size. However, there was no effect of adult G. agilis size on this parameter: for a given host size, the size of G. agilis offspring did not differ between small and large mothers. Our results reveal that host quality is mostly pre-determined, irrespective of maternal size.

The ground-cover vegetation, commonly found in olive groves, provides shelter and vital floral resources for syrphids. Such resources can contribute to syrphids' growth, development, reproduction, and survival, allowing them to maximize their function as natural pest enemies, pollinators, and decomposers of organic matter. Therefore, identifying the flowering plant families driving the abundance of Sphaerophoria scripta Linnaeus, 1758, is essential to promote its presence and abundance. Here, we described the flowering plants present in the vegetation cover of olive groves and studied how these flowering plant families shape the abundance of S. scripta. A total of 90 plant species belonging to 20 families were identified. Asteraceae was the dominant flowering family, followed by Poaceae. The generalized linear model showed that the presence of flowering plants of the families Campanulaceae, Asteraceae, Orobanchaceae, and Plantaginaceae in the ground-cover vegetation promotes the abundance of S. scripta in olive groves. Conversely, flowering plants of the families Poaceae and Polygonaceae were associated with the decreased abundance of this syrphid species. Our results suggest that increasing particular plant families and decreasing others in the ground-cover vegetation may favor S. scripta abundance in the Mediterranean olive groves.

Heat stress can significantly affect the survival, metabolism, and reproduction of honeybees. It is important to understand the proteomic changes of honeybees under heat stress to understand the molecular mechanism behind heat resistance. However, the proteomic changes of honeybees under heat stress are poorly understood. We analyzed the proteomic changes of Apis mellifera Ligustica (Hymenoptera: Apidae) under heat stress using mass spectrometry-based proteomics with TMT (Tandem mass tags) stable isotope labeling. A total of 3,799 proteins were identified, 85 of which differentially abundance between experimental groups. The most significant categories affected by heat stress were associated with transcription and translation processes, metabolism, and stress-resistant pathways. We found that heat stress altered the protein profiles in A. mellifera, with momentous resist proteins being upregulated in heat groups. These results show a proof of molecular details that A. mellifera can respond to heat stress by increasing resist proteins. Our findings add research basis for studying the molecular mechanisms of honeybees' resistance to heat stress. The differentially expressed proteins identified in this study can be used as biomarkers of heat stress in bees, and provide a foundation for future research on honeybees under heat stress. Our in-depth proteomic analysis provides new insights into how bees cope with heat stress.

To elucidate phylogenetic relationships within the leafhopper's subfamily Megophthalminae (Hemiptera: Cicadellidae), mitogenomes of 12 species of the subfamily were sequenced and assembled. These were added to the mitogenomes of the eight other species that are currently available. Mitogenome size ranged from 15,193 bp in Onukigallia onukii (Matsumura, 1912) to 15,986 bp in Multinervis guangxiensis (Li and Li, 2013), they all contained 37 genes, and gene order was similar to that in other leafhoppers. Nucleotide composition analysis showed that the AT content was higher than that of GC, and the protein-coding genes usually ended with A/T at the 3rd codon position. The Ka/Ks ratio showed that the CYTB gene has the slowest evolutionary rate, while ND4 is the gene with the fastest evolutionary rate. Relative synonymous codon usage analysis revealed the most frequently used codon was UUA (L), followed by CGA (R), and the least frequently used codon was CCG (P). Parity plot and neutrality plot analyses showed that the codon usage bias of mitochondrial genes was influenced by natural selection and mutation pressure. However, natural selection plays a major role, while the effect of mutation pressure was small. Effective number of codons values were 40.15-49.17, which represented relatively low codon bias. Phylogenetic analyses based on three datasets (AA, 13PCG, 13PCG_2rRNA) using two methods (maximum likelihood and Bayesian inference). In the obtained topology, the Megophthalminae species were clustered into a monophyletic group. In conclusion, our results clarify structural modules of the mitochondrial genes and confirm the monophyly of Megophthalminae within Cicadellidae.

The Colorado Potato Beetle, Leptinotarsa decemlineata Say, is the principal defoliator of potato crops globally. It is well known for its propensity to rapidly develop resistance. Thus, new control options which are resilient to the pest's resistance capabilities are a critical need. The use of chemical ecology in integrated pest management (IPM) programs has been proposed as a means to delay resistance. Elicitors are chemical growth regulators that activate plant defenses. These plant defenses provide numerous opportunities to integrate chemical ecology into IPM programs, including changes to a plants volatile profile. In this laboratory study, we provide evidence that elicitors which mimic jasmonic acid (JA) and salicylic acid (SA) can be used to attract or repel L. decemlineata respectively. Adult beetles are highly attracted to potato plants sprayed with the JA mimicking elicitor Blush 2X, while plants sprayed with SA mimicking elicitor, Actigard 50WG, appear to be repellent. Additionally, residency time on plants sprayed with Actigard 50WG was significantly shorter than with control plants. The potential use of elicitors within IPM program is discussed.

The beet webworm (BWW), Loxostege sticticalis (L.), is a notorious migratory agriculture pest of crops and fodder plants, inducing sudden outbreaks and huge losses of food and forage production. Quantifying its spatiotemporal patterns and possible dynamics under future climate scenarios may have significant implications for management policies and practices against this destructive agriculture pest. In this paper, a database containing nearly 7,000 occurrence records for the spatiotemporal distribution of BWW in China was established and its possible dynamics under future climate scenarios predicted using Maxent. We found that BWW could affect a vast geographic range of Northern China, about one third of the country's land area. The beet webworm overwintered in most of its distribution regions. Maxent model found a northward movement and distribution reduction for BWW in China under future climate scenarios. The occurrence and overwintering regions will move northward about 0.3°N-0.9°N under warming climate scenarios, and about 40%-70% of the suitable habitat and overwintering habitat will disappear by 2100. Most of the northward movement and suitable area reduction likely will happen in 2 decades. Given the vast affected area, the abrupt outbreaks, the diverse host plants, the sensitivity to climate change, as well as their long-distance migration capacity, global scale research, and monitoring the population dynamics of BWW are essential for developing effective management strategies and mitigating its impact on agriculture and ecosystems.

Generalist arthropod predators have historically contributed to the suppression of arthropod pests in many agroecosystems. The successful implementation of integrated pest management (IPM) programs hinges on the incorporation of insecticides that are compatible with the biological attributes of natural enemies of pests. A potentially promising pathway is improving biological control by natural enemies through the timely application of selective insecticides. In our study, adult predators were exposed to commercially available insecticides (cyantraniliprole and pyriproxyfen) using a combined laboratory and field approach to assess their effects on survivorship and predation. We isolated 2 predators, Hippodamia convergens Guérin-Méneville and Geocoris punctipes (Say), in the laboratory to estimate the survivorship and consumption of whitefly nymphs, Bemisia tabaci (Gennadius). In the field, we deployed whitefly nymph-infested potted cotton plants in replicated cotton plots with both insecticide treatments. We enumerated whitefly nymph populations on enclosed (predator-exclusion) and open (predator-accessible) potted plants. While pyriproxyfen had a negligible effect on the predators, cyantraniliprole exposure directly affected H. convergence by reducing survivorship duration and indirectly influenced both predators by reducing prey consumption and altering the consumption of alternative prey. In field conditions, regardless of pesticide exposure, whitefly-infested potted plants that excluded predators had more whiteflies than predator-accessible potted plants. Overall, pyriproxyfen demonstrated minimal impact on the predators in the laboratory or field, while cyantraniliprole adversely influenced mortality and indirect foraging under controlled laboratory conditions but did not have a significant impact in the field.

Glenea cantor (Fabricius) is an important forest pest that mainly attacks kapok trees, breaking down cellulose and lignin through 3 enzyme activities: endoglucanase, filter paper enzyme, and cellobiase. In this study, we unveiled the cloning and expression of 10 endoglucanase genes, GcEGase5A1, GcEGase5A2, GcEGaseZ2, GcEGaseZ3, GcEGaseZ4, GcEGaseZ5, GcEGaseZ7, GcEGaseZ8, GcEGaseZ9, and Cellulase, all of which exhibit enzymatic activities in G. cantor. These findings indicated that Cellulase shares sequence homology with beetle GHF45, whereas the other 9 endoglucanase genes are homologous to beetle GHF5. GcEGaseZ4 presented the highest expression in the foregut. In contrast, GcEGase5A2 and Cellulase presented peak expression in the midgut. Furthermore, GcEGaseZ7 was identified as the most highly expressed endoglucanase in the hindgut. Functional assays confirmed the ability of GcEGaseZ7 and Cellulase to degrade cellulose, and their cellulase activities were 75.57 ± 1.21 U/mg and 344.79 ± 6.91 U/mg, respectively. These results enhance our understanding of the complex cellulase system in insects and provide insights into the efficient digestion of cellulosic materials by wood-consuming insects. This research also has potential applications in bioenergy production and the development of biomaterials from lignocellulosic biomass.

In parasitoid wasps, body size is a key predictor of reproductive success, as size is often correlated with increased gamete production. In Hymenoptera, due to haplodiploid sex determination, sperm are required to produce daughters but not sons, so sex allocation relies on a female's ability to obtain and manage a finite supply of sperm. Body size may, therefore, affect sex allocation if smaller males provide fewer sperm, or if larger, more fertile females deplete their sperm supplies by fertilizing more eggs. We examined the importance of male and female body size on offspring production and sex allocation in the parasitoid, Nasonia vitripennis (Walker). We predicted larger females would experience constrained sex allocation due to limited sperm, especially if mated with smaller males. We categorized 80 males and 80 females by size (large or small) into 4 mating groups: large females with large or small males, and small females with large or small males. We analyzed brood size and offspring sex ratios after each female oviposited on 12 pupae of Sarcophaga bullata (Parker). Overall, larger females produced more offspring and a greater proportion of males. Sex ratios became more male-biased with increased offspring production, indicating that sperm depletion had affected sex allocation in larger females. In contrast, male size did not affect sex allocation, but exhibited a small positive effect on females' offspring production. Our study highlights a complex relationship between body size, fecundity, and sex allocation, enhancing our understanding of reproductive strategies in haplodiploid organisms.