Insect Science最新文献

Disruption of reproduction is an important pest control tactics for management of high-fecundity pests like Helicoverpa armigera (Hübner). In this study, we investigated the role of the testis-biased miR-252a-5p in regulating gonad development and reproduction. Through a combination of bioinformatics prediction, dual luciferase reporter assays, functional injections (agomir, antagomir, and siRNA), and phenotypic evaluations, we identified OVOL as a key target gene of miR-252a-5p. We found that miR-252a-5p negatively regulates OVOL expression. Injection of miR-252a-5p agomir or OVOL siRNA into newly emerged females delayed egg maturation and reduced hatching rates. In contrast, inhibiting miR-252a-5p or knocking down OVOL in larval stages did not affect testis development or fertility. These results demonstrate that miR-252a-5p specifically targets OVOL to modulate ovarian development and reproductive success in H. armigera. Both miR-252a-5p and OVOL represent promising targets for reproduction-based control of this and other lepidopteran pests.

This study aimed to explore the reason for Haemaphysalis longicornis restricting Borrelia burgdorferi colonization and transmission from the perspective of gut microbiota, and to investigate the impact of different infection statuses on the Haemaphysalis longicornis microbiota and its potential role in pathogen transmission. Pathogen-free Haemaphysalis longicornis ticks and IFNAR1^-/- mice were used to establish infection models. Ticks fed on pathogen-infected mice, and their midguts were analyzed at day 4 and 10 post-feeding. DNA was extracted from the midguts, and the V3-V4 region of bacterial 16S rRNA gene was amplified and sequenced. Analysis of microbiome data were analyzed using QIIME2 and R. After digesting the bloodmeals, the gut microbiota of ticks that ingested bloodmeal with Borrelia burgdorferi exhibited minimal structural changes, while the ticks with uninfected bloodmeal or bloodmeal with Langat virus showed the dysbiosis. The Borrelia group showed minimal temporal shifts in β-diversity, with stable co-occurrence networks and increased core microbial interactions. Neutral model analysis revealed a hybrid niche in the Borrelia group. Potential biomarkers were identified that may suppress Borrelia burgdorferi transmission. Our findings reveal that Borrelia burgdorferi infection is associated with a stabilized and functionally distinct gut microbiota in Haemaphysalis longicornis. The gut microbiota of Haemaphysalis longicornis functions as a barrier against Borrelia burgdorferi colonization and transmission through microbial regulation and resource limitation, thus providing a potential mechanistic explanation for the observed vector incompetence. These findings highlight the potential of microbiome-targeted strategies to block pathogen transmission and offer new insights into vector-borne disease.

The industrial scaling of Hermetia illucens production for waste bioconversion and alternative protein provision is severely constrained by logistical challenges in breeding stock preservation and long-distance transport. To address this, we developed and optimized stage-specific cold storage protocols to significantly prolong the shelf-life of H. illucens. Through a multi-stage experimental approach, we determined that 1-d-old eggs can be successfully stored at 17 °C for 10 d with 50.0% hatchability, larvae retained a 72.8% survival rate after 30 d at 15 °C, and prepupae maintained a 75.3% eclosion rate following 60 d at 14 °C. In addition, a key innovation of this study was the strategic use of dietary cryoprotectants to markedly enhance cold tolerance. Under a severe discriminating temperature (-5 °C), supplementation with 4% proline and 0.5% trehalose elevated larval survival to over 80%. Furthermore, at the chronic stress of the developmental threshold (12 °C), 3% glycerol, nearly doubled larval survival rates compared to the control. The application of these optimized cryoprotectants with stage-specific storage temperatures effectively mitigated sublethal fitness costs, ensuring high post-storage performance in survival, pupation, eclosion, and reproductive output. Our findings provide a robust, comprehensive framework for synchronizing H. illucens supply chains, enabling viable long-distance transport, and facilitating the reliable industrial scaling of H. illucens production for the circular bioeconomy.

Dominance contests have important implications for the allocation of limited resources among insect individuals. Prior experiences, particularly winning and losing have been well-documented to influence the performance and outcomes of future contests across various species. This experience effect is believed to arise either from alterations in an individual's self-assessment of its fighting ability based on past experiences or from social cues generated by previous experiences that are subsequently recognized by opponents. However, the influence of previous fighting experiences on dominance contests and the underlying cognitive mechanisms in insects remains underexplored. This study aims to investigate how previous fighting experiences influence the performance and outcomes of dominance contests among bumblebee workers (Bombus terrestris) and the underlying cognitive process. Our research findings indicate that prior winning experiences significantly influence individuals' behavioral decision-making during the pre-escalation phase of contests. Specifically, individuals with previous victories demonstrate a pronounced tendency to initiate and escalate contests, providing compelling evidence that such experiences enhance their self-perceived fighting ability. Furthermore, despite conflict resolution being largely contingent upon escalated contests, prior winners consistently exhibit a markedly higher probability of securing victories. This finding suggests that previous winning experiences improve individuals' actual fighting ability. This enhanced fighting ability enables smaller individuals to overcome larger opponents. Notably, the winner effect persists for a minimum duration of 3 d. In contrast, losers did not show significant changes in performance, suggesting the absence of a pronounced loser effect. These findings provide new insights into the mechanisms underlying the winner effect in insects.

Heavy metals are widespread environmental pollutants. This study investigated the growth toxicity of cadmium (Cd) stress on Chouioia cunea offspring during the parasitism period within a Cd-contaminated food chain of artificial diets-Hyphantria cunea pupae-C. cunea. After parasitizing Cd-accumulated H. cunea pupae, the offspring exhibited a significant reduction in both body length and the expression levels of most growth regulatory genes. Transcriptome analysis revealed that, during the early parasitism stage, genes responsive to Cd stress predominantly involved the endoplasmic reticulum (ER) stress, mitochondrial dysfunction, apoptosis, and calcium homeostasis. In the subsequent stages of parasitism, Cd exposure induced substantial damage to the ER and mitochondrial ultrastructure, disrupted the antioxidant defense system, activated the mitochondrial apoptotic and ER stress pathways, and decreased the expression of SLC24A3 and SLC24A4. Overexpression of SLC24A3 and SLC24A4 in Sf9 cells mitigated Cd toxicity by alleviating the Ca²⁺-mitochondrial permeability transition pore (MPTP)-mitochondrial membrane potential (MMP) collapse/apoptosis and oxidative stress cascade reaction. Overall, Cd exposure impaired the growth of C. cunea parasitic offspring through the SLC24A3/SLC24A4-mediated apoptosis and oxidative damage signaling pathways.

Cuckoo bumblebees are obligate brood parasites that must invade a colony of their host bumblebee species in order to reproduce. As the host queen is typically killed in the colony invasion process, cuckoo bumblebees are thought to severely reduce the reproductive success of the host bumblebee species. Here, we introduce a novel colony-splitting method to investigate and quantify the reproductive impact of cuckoo parasites, applying it to common bumblebee species, Bombus terrestris and its brood parasite, Bombus vestalis. The brood and workers from commercial B. terrestris colonies were divided into two boxes. One colony half was left with the original Bombus terrestris queen-forming the "queen-right" colony-and a B. vestalis cuckoo bumblebee was introduced to the second half, becoming the "cuckoo-parasitized" colony. This paired approach minimizes differences between colony success from genetic variation or other parasites and allows for comparisons between host and cuckoo reproductive success in a controlled environment. In our experiment, cuckoo parasitism resulted in a significant loss of host reproductive success as compared to queen-right colonies. We also record a significant influence of cuckoo lifespan on the number of new cuckoos and hosts produced in parasitized colony halves. In cuckoo-parasitized colonies, we observed higher reproductive success for host B. terrestris than B. vestalis, the cuckoo bumblebee species. We suggest further refinements of this method may be needed before drawing conclusions on the comparative reproductive success of host and cuckoo bumblebees in natural environments.

The venom gland is a remarkable organ of the parasitoid wasps, which produces venom that controls the host and is important for the survival and reproduction of the parasitoid. But little is known about how venom gland cells precisely regulate venom synthesis. Here, we used single-nucleus RNA sequencing to construct the cell atlases of the venom gland and ovary of the Pteromalus puparum, a natural enemy of vegetable pests. The cells in the venom gland were clustered into six subsets, and the main cell types in the ovary were follicle cells, germline cells and nurse cells. The cellular function of venom gland subsets named VgC1 to VgC6 was enriched in the production and secretion of venom. In addition, the expression pattern of identified venom genes that 77 genes expressed across all six VgCs and 46 genes in five VgCs, demonstrated that most venom genes expressed widely in VgCs. Finally, hdWGCNA analysis of venom gland cells identified a set of co-expressed venom and non-venom genes that include putative regulators of venom production in P. puparum. Our analysis of transcription factor (TF) binding sites within the venom modules revealed that TFs such as AP-1 and EHF are potential regulators of venom genes. This work reveals the cellular heterogeneity, venom gene expression patterns, and transcriptional regulatory networks in the venom gland of P. puparum at single-cell resolution. These findings provide fundamental insights into the biology of venom-producing organs and establish a molecular foundation for developing novel biopesticides based on venom proteins.

Coastal dunes are highly vulnerable ecosystems that require adequate bioindicators for effective biodiversity monitoring. Although moths are recognized as good bioindicators in many contexts, their diversity patterns in these habitats remain understudied. This research examines the taxonomic and functional diversity of noctuoid moths in a well-preserved, protected dune system in Central Italy (Adriatic coast). Specifically, the study aimed at investigating how vegetation composition, and hence dune zonation, influences noctuoid diversity and traits. Moth sampling was carried out on an annual basis using UV LED traps in both shifting and fixed dune zones. Vegetation surveys were conducted in spring using 4 m × 4 m plots. We compared noctuoid species richness, species abundance distribution patterns, and trait attributes between the two dune zones in relation to vegetation characteristics. We also evaluated the congruence in species composition and abundance between dune zones for both moths and plants. Sampled noctuoids included 98 species (78 Noctuidae, 18 Erebidae, 1 Nolidae, and 1 Notodontidae). The presence of habitat-exclusive species underscores the influence of both abiotic and biotic filtering processes in shaping noctuoid assemblages across the seashore-inland zonation. Trait-based analyses and diversity patterns showed clear ecological links between noctuoid assemblages and dune zones. This congruence supports the use of noctuoid moths as effective bioindicators and stresses the need to conserve the entire dune system as an integrated ecological unit.

The tortoise scale insect (Toumeyella parvicornis) is rapidly spreading in stone pine (Pinus pinea) forests and urban parks of Mediterranean Europe. Its current distribution and potential spread is concerning as, so far, it already includes three different European countries. Pest management strategies based on endotherapic treatments have a limited time coverage and are unfeasible on large scales. Biological control can be a valuable alternative to contain the spread of T. parvicornis, as highlighted by some recent studies conducted with predators under controlled conditions. Although promising outcomes, open-field efficacy is still poorly explored. This study aimed to fill this gap in knowledge through an open-field assessment of the predation impact of Exochomus quadripustulatus and its capability of reducing T. parvicornis infestation level. Adult ladybug females were released on stone pine groups divided as follows: (i) plants treated only with ladybugs, (ii) plants pre-treated with bio-insecticide prior the release of the ladybugs, and (iii) an untreated control. The stone pine groups that received the ladybugs application, showed a lower infestation level (in terms of T. parvicornis adult females) than the untreated control, for most of the evaluation period. Results showed, for the first time, evidence of E. quadripustulatus efficacy in open-field applications, confirming the previously positive outcomes observed under laboratory and semi-field conditions. The outcomes of this study, accordingly, open the door to future biological control programs.

Bursicon is indispensable for wing expansion in Bactrocera dorsalis, acting through PKA-mediated regulation of the wing-development gene Bdhh. Although cuticular proteins are recognized as critical regulators of insect wing development, it remains unclear whether they directly respond to the bursicon signaling pathway. Here, we conducted a functional dissection of cuticular protein genes during wing expansion. Transmission-electron-microscopy (TEM) analysis revealed that bursicon controls endocuticle development in the wing cuticle. Genome-wide mining uncovered sixteen CPR-type endocuticle structural glycoprotein genes, of which three cuticular protein genes (BdABD-4a, BdABD-4b, and BdABD-4c) were selected for RNAi on the basis of their expression profiles. Silencing of each gene via dsRNA injection at the 5-d-old pupal stage produced wing malformations in 37.5%, 32.5%, and 40% of adults, respectively, and reduced cuticle thickness by 40.4%, 42.4%, and 44.2% relative to controls. TEM confirmed the presence of thinner endocuticle in malformed wings. Furthermore, expression levels of all three endocuticle structural glycoprotein genes were markedly altered following knock-down of Bursicon genes, Bdhh and after PKA inhibition, indicating that these proteins operate downstream of the bursicon signaling cascade. The results in this study demonstrated that the functional role of BdABD-4a, BdABD-4b, and BdABD-4c in wing expansion, and provide new insights into the molecular mechanism underlying bursicon regulated wing expansion in B. dorsalis.