Yu Peng

Aphid honeydew is generally regarded as a sugar‐rich excretion, but it also contains microbial communities that may influence plant–herbivore interactions. Whether honeydew‐associated bacteria suppress plant defense responses to enhance aphid performance remains unclear. Here, we investigated the effects of honeydew‐associated bacteria from the cotton‐melon aphid, Aphis gossypii , on defense responses in zucchini ( Cucurbita pepo ) and subsequent aphid performance. Compared with sterilized honeydew, crude honeydew significantly increased aphid body weight, suggesting that honeydew‐associated bacteria contribute to enhanced aphid performance. This effect was associated with attenuation of multiple jasmonic acid (JA)‐ and salicylic acid (SA)‐associated defense responses, including reduced expression of several defense‐related genes, lower accumulation of free JA and free SA, and reduced PPO activity. Further assays with individual bacterial isolates showed that Mammaliicoccus sp. and Pseudomonas sp. significantly increased aphid body weight, whereas bacterial effects on JA‐ and SA‐related gene expression and PPO activity were isolate‐ and time‐dependent. Together, these results show that honeydew‐associated bacteria can suppress zucchini defense responses and enhance the performance of A. gossypii . Our findings reveal honeydew microbiota as microbial modulators of plant–aphid interactions.

Summary: Heterostyly is a classic Darwinian adaptation promoting disassortative pollination. The polymorphism usually depends on floral tubes to enforce spatial segregation of pollen deposited on pollinators. How this is achieved in species with bowl‐shaped flowers and generalised pollinators remains less well‐understood. We investigated the mechanistic basis of Darwin's cross‐promotion hypothesis in distylous Persicaria jucunda , which lacks a floral tube and is fly‐pollinated. We integrated morphological measurements of flowers and flies with high‐definition video analysis of foraging behaviour. Exploiting pollen‐size dimorphism, we quantified morph‐specific pollen placement on pollinator body parts and the composition of naturally pollinated stigmatic pollen loads. A ‘morphological fit’ was evident with fly proboscis length matching lower‐level sex organs and upper‐level organs matching the position of the head. This morphological congruence caused L‐morph pollen to be deposited primarily on proboscides (76.6%) and S‐morph pollen on heads (85.7%), resulting in a significantly higher proficiency of intermorph than intramorph pollen transfer. Despite the absence of a floral tube in P. jucunda , our findings of a morphological fit between flower and pollinator structures and consistent foraging behaviour by flies provide mechanistic support for Darwin's cross‐promotion hypothesis and resolve the puzzle of how disassortative pollination occurs in open‐flowered heterostylous systems.

Arachnids evade predation by intentionally sacrificing body parts, with leg autotomy playing a crucial role in their survival and reproductive strategies. Our study primarily employed field surveys and laboratory experiments to examine the frequency of autotomy and its effects on predation and mating in Ebrechtella tricuspidata (Araneae: Thomisidae). Leg loss was common in wild populations, with approximately 17.11% of all surveyed spiders missing at least leg, the most frequently lost leg is one of the second pair of appendages, and the highest rate of autotomy occurs in July. Additionally, we found that some individuals exhibit regenerative capacity following autotomy. We focused on the effects of leg autotomy on E. tricuspidata in two contexts: predation and mating. In laboratory conditions, the loss of two legs significantly impacted the individual’s predatory efficiency. Additionally, individuals missing two legs exhibited significantly poorer mating performance than intact individuals. We suggest that E. tricuspidata may employ a synergistic strategy of “autotomy-regeneration” to mitigate survival risks, thereby reducing the negative impacts of leg loss on predation and mating.

Climate change may exacerbate biological invasion by expanding the distribution of invasive species. Pseudorasbora parva (Temminck & Schlegel, 1846) is a prevalent invasive fish species. It has posed significant threats to biodiversity and ecosystems in over 40 countries across Asia, Europe, and Africa. To avoid or mitigate its threats, it is necessary to evaluate its invasion risk. Species distribution models (SDMs), using occurrence data and bioclimatic factors, serve as critical tools for evaluating biological invasion risks. ANN, FDA, GAM, GBM, MARS, and RF are prominent individual algorithms. Ensemble models are generally considered better than individual algorithms as they can effectively reduce uncertainties. However, no study has yet used ensemble models to forecast the global distribution of P. parva under future climate change. Therefore, the aim of this study was to use ensemble SDMs, combined by above‐mentioned six individual algorithms, to predict the global potential suitable habitats and influencing factors of P. parva under current and future climate change. Global occurrence data for P. parva were collected from online biodiversity platforms and literature databases. Bioclimatic variables were from WorldClim and ENVIREM. The results showed as follows: (1) The ensemble model demonstrated excellent performance with an AUC of 0.993; (2) The two bioclimatic factors exerting the most significant influence on P. parva distribution were the maximum temperature of the coldest month and isothermality, contributing 51.362% and 18.279% respectively; (3) The distribution of P. parva in the current period, as generated by the ensemble model, revealed that the primary invasion areas are concentrated at latitude 22°–55° N; (4) Future projections under various climate scenarios indicated an overall range expansion, with high‐latitude or high‐altitude regions becoming increasingly favorable. These findings suggest that the future global expansion trend of P. parva should not be ignored and effective management policies for its invasion should be provided.

This study aimed to investigate whether the attractiveness of female dragline silk sex pheromones in the wolf spider Pardosa pseudoannulata varies with female age, and to identify the key chemical compounds responsible for male attraction. We conducted integrated behavioral, chemical, and electrophysiological analyses. Dragline silk was collected from females of three age groups (young, middle‐aged, and old). Male courtship behaviors were assessed in response to silk exposure. Silk extracts were analyzed using gas chromatography coupled with electroantennographic detection and mass spectrometry. Candidate pheromone compounds were further evaluated via electroantennography and Y‐tube olfactometer assays to confirm their behavioral relevance. Male spiders exhibited significantly stronger courtship responses, shorter latency, higher palpal drumming, and increased leg vibration, toward silk from young and middle‐aged females compared to older females. Three compounds—oleic acid, n‐heptacosane, and squalene—were consistently identified as key pheromone components across age groups. Their electrophysiological activity was concentration and solvent dependent, while behavioral attraction was confirmed under tested conditions. In behavioral assays, synthetic versions of these compounds at 0.01 µg/µL in mineral oil significantly attracted males, confirming their role as sex pheromone components. The findings demonstrate that female age significantly influences the chemical composition and attractiveness of dragline silk pheromones in P. pseudoannulata . Younger females produce more attractive pheromone blends, guiding male mate preference. The identification of oleic acid, n‐heptacosane, and squalene as bioactive compounds provides new insights into spider chemical ecology and supports potential applications in eco‐friendly pest management strategies.

Plants have evolved intricate defense strategies to combat herbivorous insect attacks, including the production of toxic secondary metabolites and the attraction of natural enemies. While bacterial-mediated direct toxicity in plant defenses has been demonstrated, the ecological mechanisms by which plants utilize bacteria to indirectly modulate the behavior of natural enemies remain insufficiently explored. In this study, we observed a significant enrichment of Staphylococcus in the tissues of zucchini Cucurbita pepo following infestation by the cotton-melon aphid Aphis gossypii. These bacteria traced from the damaged plant stems and leaves were subsequently found both in aphids and in their secreted honeydew. Among the four dominant bacterial strains isolated from the honeydew, Staphylococcus sp. markedly promoted oviposition preference in mated female ladybird beetles Propylea japonica. Further investigation identified a volatile organic compound, 4-Isopropylbenzyl alcohol, released by Staphylococcus sp. that stimulated strong antennal responses and attracted P. japonica to lay eggs. Collectively, our findings demonstrate that zucchini plants can employ indirect defense against A. gossypii through the enrichment of specific bacteria, revealing a novel ecological role for bacteria in plant defense and expanding our understanding of complex plant–microbe–insect–natural enemy interactions.

Numerous flower visitors exhibit varying preferences for floral characteristics. As one group of flower visitors, the preferences of spiders for flower colour have garnered attention; however, their preferences for the morphological characteristics of flowers remain largely unexplored. This study investigated the preferences of flower‐visiting crab spiders Ebrechtella tricuspidata for flower size, petal density and symmetry, and explored the underlying reasons from the courtship and predation. The results showed that male spiders preferred larger flowers, while females favored densely petaled flowers and symmetrical flowers under the experimental conditions. Additionally, males showed a tendency to choose females that sitting on larger flowers than on smaller ones. Furthermore, consistent with spider choices, the potential prey houseflies and honeybees, also tended to visit larger, densely petaled, and symmetrical flowers in visitation experiments. We propose that prey preferences for floral characteristics may be a primary factor influencing spider preferences. We hypothesize that the flower characteristics influence insect visitation preferences, which may extend to third trophic level predators, thereby determining the preferences of flower‐visiting spiders. Overall, our research provides new insights and evidence regarding spider selection behavior toward floral characteristics, emphasizing that these preferences may facilitate both predation and mating in spiders.

Tebuconazole is a widely used triazole fungicide to control fungal diseases. While there have been reported side effects on non-target arthropods, its ecological risks to natural enemies remain poorly understood. In this study, we evaluated the developmental toxicity and symbiotic microorganism responses of the wolf spider Pardosa pseudoannulata, an important predator in rice ecosystems, following exposure to tebuconazole. The results indicated that tebuconazole did not significantly increase the mortality rate of spiderlings; however, it did lead to a significant decrease in spiderling body weight, as well as the length and width of the carapace. High-throughput sequencing of the 16S rRNA gene V3–V4 regions and the ITS region revealed that tebuconazole significantly reduced bacterial diversity indices in the short term, with a gradual recovery over time. In contrast, the impact on the fungal community was continuous and irreversible, with a significant decrease in the Shannon index observed after 15 days. At the genus level, the relative abundances of Cupriavidus and Staphylococcus in the bacterial community decreased significantly after tebuconazole exposure, while Stenotrophomonas increased. In the fungal community, Fungi_gen_Incertae_sedis decreased significantly, and Simplicillium increased. Our findings highlight the ecological risks of fungicide exposure to beneficial predators and underscore the importance of considering symbiotic microbiota in pesticide risk assessments.