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Abstract Next-generation sequencing allows for fine-scale studies of microbial communities. Herein, 16S ribosomal RNA high-throughput sequencing was used to identify, classify, and predict the functions of the bacterial communities in the eggs and ovaries of Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), which is a pest that infests a variety of cucurbit fruits at different developmental stages. Taxonomic analyses indicate that bacteria associated with B. cucurbitae represent 19 phyla, which were spread across different developmental stages. Specifically, the egg microbiota had a higher alpha diversity than those of microbiota in the primary and mature ovaries. Significant differences were not observed between the primary and mature ovaries in terms of their microbiota’s alpha diversities. Pseudomonadota, Deinococcota, Bacteroidota, Bacillota, and Actinomycetota were the dominant phyla in all three developmental stages of B. cucurbitae, and Pseudomonadaceae and Enterobacteriaceae were the most abundant families. Owing to the unique physiological environment of the ovaries, the diversity of their bacterial community was significantly lower than that in the eggs. This study provides new insights into the structure and abundance of the microbiota in B. cucurbitae at different developmental stages and contributes to forming management strategies for this pest.

Common ragweed (Ambrosia artemisiifolia) is a notorious invasive weed that has spread across most temperate regions of the world. The beetle (Ophraella communa) is considered to be an effective control agent against A. artemisiifolia. As an oligophagous insect, its olfactory system is extremely important for host seeking in the wild. To the best of our knowledge, there is no report on the molecular mechanisms underlying olfaction recognition in this beetle. Hence, in this study, we characterized the odorant receptor co‐receptor of O. communa and named it as 'OcomORco'. Real‐time quantitative PCR (qRT‐PCR) showed that, compared to the control treatment, RNA interference (RNAi) strongly reduced the expression of OcomORco by 89% in male and 90% in female beetles. Electroantennogram assay showed that the antennal response of both male and female beetles to four volatiles of A. artemisiifolia was significantly reduced. The injected male or female beetles lost their preference for plant leaves as observed in the behavioural tests. In addition, disruption of the expression of OcomORco resulted in a reduction of oviposition, while there was no difference in larval hatching rate between control and knockdown females. We demonstrated that OcomORco plays a vital role in olfactory perception and host search in O. communa, and it is involved in oviposition in an indirect way. [ABSTRACT FROM AUTHOR]

Increase in atmospheric CO2 directly affects the insect physiology and behavior, and indirectly affects the herbivorous insects by affecting their hosts. The increase in atmospheric CO2 is accompanied by an increase in temperature and heat waves. Ophraella communa LeSage is a natural enemy of Ambrosia artemisiifolia (common ragweed). The development and reproduction of this beetle is weakened upon eating common ragweed grown under stress conditions. As female behavior and physiology alter after mating, the reproductive tract of males is likely to modulate reproduction and development in this species. Herein, the transcriptional profiles of testes and accessory glands from male O. communa individuals feeding on common ragweed under conditions of high CO2 concentration and heat waves and that grown under ambient CO2 concentration were compared. Differentially expressed genes (DEGs) were identified between the same tissues from beetles fed on common ragweed grown under different stress conditions. There were 3, 2, 3, 1and 5 genes related to decomposition and transport of macromolecular substances, host location, stress response, reproduction, and poisonous food-utilization. No expected response was observed in the male reproductive tract, but some of the identified DEGs might control the development of the population. The results presented here should be helpful in guiding future studies on deciphering the indirect response of other organs to high CO2 concentration and heat waves, as well as the functions of seminal fluid proteins in O. communa. [ABSTRACT FROM AUTHOR]

Background: Bactrocera cucurbitae (Coquillett) is a distructive quarantine insect pest that causes significant economic losses on cucurbit crops. To explore a green control approach, we investigated the behavioral responses of B. cucurbitae larvae and adults to bacterial suspensions, sediments, and supernatants derived from eight gut microbial strains across four distinct genera. The proboscis extension response was used to evaluate the impact of these microbial strains. In addition, using food selection experiments, two-choice trap methods, and gas chromatography-mass spectrometry, we isolated and identified the predominant volatile compounds in the microbiota supernatants., Results: Among the tested gut microbial strains, Kluyvera, Morganella, and Providencia exhibited notable attraction toward B. cucurbitae. In particular, the supernatant of Providencia M38 revealed the most highly attractive effect on B. cucurbitae larvae, whereas the supernatant of Morganella M72 was highly attractive to B. cucurbitae adults. Primary components present in the supernatant of M38 and M72 were dimethyl disulfide, indole, 2-nonone, phenethyl alcohol, and 1-decanol., Conclusion: Strains of M38 and M72 displayed remarkable attractive properties for B. cucurbitae larvae and adults, respectively, presenting promising potential for developing a novel attractant for this pest species. © 2025 Society of Chemical Industry., (© 2025 Society of Chemical Industry.)

To predict and mitigate the effects of climate change on communities and ecosystems, the joint effects of extreme climatic events on species interactions need to be understood. Using the common ragweed ( Ambrosia artemisiifolia L.)-leaf beetle ( Ophraella communa ) system, we investigated the effects of heat wave and elevated CO 2 on common ragweed growth, secondary metabolism, and the consequent impacts on the beetle. The results showed that elevated CO 2 and heat wave facilitated A. artemisiifolia growth; further, A. artemisiifolia accumulated large amounts of defensive secondary metabolites. Being fed on A. artemisiifolia grown under elevated CO 2 and heat wave conditions resulted in the poor performance of O. communa (high mortality, long development period, and low reproduction). Overall, under elevated CO 2 , heat wave improved the defensive ability of A. artemisiifolia against herbivores. On the other hand, enhanced adaptability to climatic changes may aggravate invasive plant distribution, posing a challenge to the control of invasive plants in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Tian, Ma, Zhao, Zhang, Gao, Tian, Chen, Guo and Zhou.)

Increase in atmospheric CO 2 directly affects the insect physiology and behavior, and indirectly affects the herbivorous insects by affecting their hosts. The increase in atmospheric CO 2 is accompanied by an increase in temperature and heat waves. Ophraella communa LeSage is a natural enemy of Ambrosia artemisiifolia (common ragweed). The development and reproduction of this beetle is weakened upon eating common ragweed grown under stress conditions. As female behavior and physiology alter after mating, the reproductive tract of males is likely to modulate reproduction and development in this species. Herein, the transcriptional profiles of testes and accessory glands from male O. communa individuals feeding on common ragweed under conditions of high CO 2 concentration and heat waves and that grown under ambient CO 2 concentration were compared. Differentially expressed genes (DEGs) were identified between the same tissues from beetles fed on common ragweed grown under different stress conditions. There were 3, 2, 3, 1and 5 genes related to decomposition and transport of macromolecular substances, host location, stress response, reproduction, and poisonous food-utilization. No expected response was observed in the male reproductive tract, but some of the identified DEGs might control the development of the population. The results presented here should be helpful in guiding future studies on deciphering the indirect response of other organs to high CO 2 concentration and heat waves, as well as the functions of seminal fluid proteins in O. communa ., (Copyright © 2020 Gao, Tian, Zhang, Chen, Ma, Tian, Cui, Lu and Zhou.)