摘要: Insulin-like peptides (ILPs) act as crucial reproductive neuropeptides in insects, regulating insect reproduction through the insulin signaling pathway (ISP). Our previous studies have found that the sublethal concentrations (LC1 and LC10) of lambda-cyhalothrin (lambda Cy) could induce severe reproductive toxicity in the lacewing, Chrysoperla sinica (Tjeder), but the toxicological mechanism remains unclear. This study discovered that lambda Cy could inhibit CsILP transcription, leading to a decrease in insulin content and downregulation of C. sinica insulin receptor (CsInR) and C. sinica forkhead box O (CsFOXO) expression in ISP. Interference with CsILP expression resulted in downregulation of C. sinica vitellogenin (CsVg) and decreasing fecundity, while exogenous injection of bovine insulin promoted upregulation of CsVg expression and facilitated reproduction in female adults of C. sinica. Meanwhile, interference with FOXO of ILP downstream transcription factor could lead to downregulation of CsVg, hindering ovarian development and resulting in a decrease in egg production. However, exogenous injection of bovine insulin could remedy the effects caused by FOXO interference. In addition, ILP mediates juvenile hormone and 20-hydroxyecdysone biosynthesis by acting on their synthetic regulatory enzymes and influences the signal transduction of the 2 reproductive endocrine hormones, thereby regulating the reproductive endocrine environment in C. sinica. In conclusion, lambda Cy inhibits CsILP expression, leading to disorder of ISP, leading to the reduced fecundity of C. sinica.

摘要: Water stratification is a prominent oceanographic phenomenon in the North Yellow Sea, a vital region for mollusk aquaculture in northern China. Understanding the influences of water stratification on planktonic bacterial communities in those waters is crucial for the sustainable development of mollusk aquaculture in this region. In the present study, the bacterial community profiles across different water layers in a representative Yesso scallop farming area of Zhangzi Island in the North Yellow Sea were surveyed from March 2021 to January 2022. Water stratification was present in June, July, and August (the stratification period, abbreviated as S period) and absent in March, October, and January (the mixing period, abbreviated as M period), based on the vertical distribution of water temperatures. Results of the 16S rRNA gene sequencing showed that the alpha diversity of bacterial communities in the S period (Chao1 index: 500.78, Shannon index: 6.85) was significantly lower than in the M period (Chao1 index: 575.00, Shannon index: 7.24). The relative abundances of Synechococcus CC9902 and Vibrio were significantly higher in the S period compared to the M period, while the abundance of Clade Ia showed the opposite trend. Water temperature, salinity, and dissolved inorganic nitrogen were identified as the main environmental drivers of the bacterial communities, which accounted for 22.4%, 20.0%, and 17.1%, respectively, of the total variation in bacterial community composition. Functional prediction suggested that the pathways associated with cytochrome biosynthesis and nutrient utilization of the bacterial communities were significantly enriched in the S period, while those involved in energy metabolism were enhanced in the middle and bottom layers compared to the surface layer during the S period. The connectivity of the molecular ecological network increased in the S period, with the number of edges, average degree, and average clustering coefficient being 574, 11.36, and 0.57 in the S period and 524, 9.44, and 0.51 in the M period, respectively. Collectively, these results indicated that water stratification led to a decrease in bacterial community diversity and an increase in the relative abundance of Synechococcus CC9902 and Vibrio, which were potentially detrimental to mollusk health and aquaculture. Our results contribute to clarifying the dynamics of planktonic bacterial communities and their impacts on mollusk aquaculture in the context of intensifying ocean stratification.

摘要: The adaptive strategies of prey against predation risk have been pivotal in non-consumptive effects. However, the adaptive strategies of prey and the response mechanisms to various predation risk cues remain unclear. We hypothesized that prey adopt a similar adaptive strategy to address different predation risks, but their response mechanisms depend on the attributes of predation risk cues. To test this hypothesis, we used Didinium-Paramecium as a predator-prey model to first evaluate the effects of various predation risk cues, including homogenates of predators (TD) and prey (TP) alone or in combination (TM), and the density of conspecific prey on the specific growth rate (SGR) to determine their adaptive strategies and their underlying response mechanisms based on transcriptomic analysis. Our results show that predation risk cues considerably enhance prey SGR, with effects in descending order of TM, TD, and TP. However, such effects gradually decrease as the density of conspecific prey increases until they disappear. The trend in the levels of differentially expressed genes (DEGs) in prey exposed to different predation risk cues is similar to that of SGRs. In particular, pathways based on DEG enrichment mediated by predation risk cues involve cellular processes, nutrient metabolism, and synthesis of biological macromolecules. However, they differ in type, number, and location within specific biological processes. In conclusion, Paramecium uses early reproduction strategies to address the risk of predation caused by different cues, and differences in its response mechanisms depend on the attributes of the cues of predation risk, resulting in differences in the SGR of the prey.

摘要: Aquaculture, as a major source of protein in the food industry, heavily relies on the introduction and farming of non-native species. Pikeperch, Sander lucioperca, an important fish in aquaculture, poses a threat to the survival of native species because it is a piscivore and has been introduced globally. To address this issue, we examined the niche dynamics of invasive populations by comparing the climatic niches of native and invasive populations of Pikeperch. Predictive models based on global occurrence data were used to assess the distribution areas of native and invasive populations, and the model results were converted into area measurements to estimate the potential invasion risk of pikeperch. The results show that invasive populations, especially those in Asia, occupy broader climatic niches. The main difference is that, compared to native-range populations, non-natives occupy warmer and more humid regions. These climatic differences have led to niche expansion by invasive populations, with invasive populations (particularly in Asia) showing a greater potential for invasion. we applied niche modeling to evaluate the potential invasion risks associated with introducing different geographic populations. Our models provide a scientific basis for managing aquaculture introductions, aiming to reduce invasion risks and minimiz both ecological and economic impacts.

摘要: Water level variations (WLVs) substantially affect the spatial distribution of riparian vegetation. Accurately quantifying the water level fluctuation requirements (WLFRs) of aquatic macrophytes is essential for effective ecological water level management. Nevertheless, studies on the WLFRs of herbaceous plants in large river floodplains, such as Phragmites australis (common reed) and Phalaris arundinacea (reed canarygrass), are limited. Herein, we investigated the WLFRs of the two plants across water bodies with different WLVs in the Yangtze River Basin. We focused on the effects of sub-monthly and sub-daily WLVs on their average monthly water depth requirements (WDRs) during critical growth periods. Our findings indicated: (1) For Phragmites, during the emergence period, the upper limits of WDRs decreased with increased amplitudes of sub-monthly WLVs and with greater frequency and amplitude of sub-daily WLVs, in which sub-daily variations had a more pronounced effect. Conversely, during the rapid growth period, the upper limits increased with larger sub-monthly WLVs amplitudes, but decreased with higher frequency and amplitude of sub-daily WLVs. (2) For Phalaris, during both the emergence and rapid growth periods, intensified sub-daily WLVs led to decreased upper limits of WDRs. In summary, although distinct disparities existed in the WLFRs of Phragmites and Phalaris across various water bodies, the trends in WDRs during the emergence and rapid growth periods were consistent for both species. These findings provide essential quantitative data to restore aquatic vegetation and carry out effective ecological water level management in large-scale riparian ecosystems.