Riptortus pedestris (Fabricius, 1775) (Hemiptera: Alydidae) is a major soybean pest in East Asia that can cause soybean staygreen syndrome. To date, no insecticides have been registered for the control of R. pedestris in China, and these insects are primarily controlled in the field through the application of broad-spectrum insecticides including lambda-cyhalothrin (LCT) and emamectin benzoate (EMB). Here, the lethal and sublethal effects of LCT and EMB on R. pedestris were comprehensively evaluated. LCT and EMB were both found to exhibit high levels of toxicity and concentration-dependent repellent effects for R. pedestris. The exposure of third instar nymphs from the F0 generation to LC30 concentrations of LCT and EMB resulted in a significant increase in the duration of nymph development and adult pre-oviposition period (APOP), together with reductions in fifth instar nymph and adult body weight, longevity, oviposition days, fecundity, vitellarium length, lateral oviduct diameter, and vitellogenin (Vg) gene expression as compared to control treatment. Strikingly, these suppressive effects were transmitted to the F1 generation, which similarly experienced the prolongation of preadult development and the preoviposition period (TPOP). Relative to control-treated populations, the F1 generation for these insecticide-treated groups also exhibited significant decreases in population parameter values. Overall, these data offer new insight into the impact that LCT and EMB treatment can have on R. pedestris, providing a valuable foundation for the application of these pesticides in the context of integrated pest management strategies aimed at soybean crop preservation.

BACKGROUND: Panonychus citri is a globally dominant citrus plant pest mite. Pesticide-induced population resurgence is a concern for mite control. Exposure to sublethal concentrations of pesticides has stimulated reproduction and outbreak risks in many pests. Pyridaben, a mitochondrial electron transport inhibitor, has been frequently used worldwide in mite control. In the study, sublethal and transgenerational effects of pyridaben exposure on Pyr_Rs (resistant) and Pyr_Control (susceptible) strains were systematically investigated in both exposed parental generation (F0 ) and unexposed offspring generations (F1 and F2 ) by evaluating life-table and physiological parameters.
RESULTS: After exposure to pyridaben, the fecundity of both strains was significantly reduced in F0 generation while significantly induced in F1 generation. Interestingly, these effects also stimulated the fecundity of the F2 generation in Pyr_Control strain while no significant effects occurred for Pyr_Rs strain. The intrinsic rate of increase (r) and finite rate of increase (λ) were significantly decreased only in F1 generation of Pyr_Control strain after exposure treatment. Meanwhile, the population projection indicated a smaller population size in F1 generation of Pyr_Control strain while a population increase for Pyr_Rs strain after sublethal treatment. Subsequent detoxification enzyme assays indicated that only P450 activities in F0 generation were significantly activated by LC30 exposure to pyridaben in both strains. Significant downregulation of reproduction-related (Pc_Vg) genes was observed in the F0 generations of both strains. Significant upregulation of P450 (CYP4CL2) and Pc_Vg of the F1 generation in both strains suggested the presence of delayed hormesis effects on the reproduction and developed tolerance to pyridaben, although the effects did not last over a longer period (F2 generation).
CONCLUSIONS: These results provide evidence for transgenerational hormesis effects of low concentrations of pyridaben exposure that may lead to population increase and resurgence risks of resistant-mites in natural settings by stimulating reproduction. © 2023 Society of Chemical Industry.

The present experiment was designed to evaluate the effect of graded level of zinc on Vitellogenin gene (Vtg) expression and antioxidant enzymes in threatened catfish, Clarias magur (C. magur). One hundred and eighty female C. magur with an average weight of 145 ± 5 g were allocated in twelve cemented tanks with dimension 4.5 × 2 × 1 m for a period of 60 days. Fish were distributed in four groups with three replicates following the completely randomised design. The first group treated as control (C) fed with basal diet contained normal zinc level, and remaining groups were fed with basal diets having 50, 200 and 300 mg/kg zinc acetate and treated as T1, T2 and T3 respectively. To evaluate the effect of dietary zinc supplementation on Vtg gene expression, three sampling were carried out, I sampling (April, before starting the experimental trail), II sampling (May, after 1 month of feeding trail) and III sampling (June before breeding season). In the present study, a dose-dependent relationship between Vtg gene expression and zinc inclusion in the diet of threatened catfish, C. magur, was reported. Vtg gene expression increased in all groups from I sampling to II sampling but the highest Vtg gene expression was found in T1 group and the lowest in T3 group at II sampling. Vtg gene expression among the treatments differs significantly (P < 0.05) in each sampling. Accumulation of zinc was measured by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) in C. magur and it was reported that the significantly higher (P < 0.05) zinc was accumulated in the liver and ovary of T3 group as compared to other groups. The antioxidant enzyme activities (superoxide dismutase, SOD, catalase and GST) were also measured in different tissues (liver, gill and ovary) to evaluate the effect of extra-supplementation of zinc on the antioxidant status. In T3 group, SOD, catalase and GST activities were significantly higher than those in other groups. In the current study, serum glucose level was also measured and it was found in increasing trend with inclusion of zinc in the diet of C. magur. In the present study, it can be concluded that the zinc exhibits beneficial effect only up to 50 mg/kg. Thus, it is concluded that supplementation of zinc at 200 mg/kg or more disrupts Vtg gene expression and antioxidant status.

A 30-day nutritional study was conducted for determining the effects of supplementing soy lecithin (SL) in the diet of female Litopenaeus vannamei. Four isonitrogenous and isoenergetic diets were supplemented with graded amounts of SL including 0 (control), 20, 40 and 60 g Kg-1. The brooding specimens fed the 40 g SL/kg diet had the greatest gonadosomatic index (3.4 ± 0.2 %) and the shortest latency period from eyestalk ablation to the first spawning (5 days). In addition, there was a larger content of long chain polyunsaturated fatty acids (LC-PUFA) in the hepatopancreas of brooding specimens fed with the 20 and 40 SL/kg diets compared to the other treatments. Furthermore, brooding specimens fed with the 40 g SL/kg diet had the greatest hemolymph cholesterol and high density lipoprotein concentrations. The abundance of vitellogenin mRNA transcript was greater in the hepatopancreas of brooding specimens fed with the 40 and 60 g SL/kg diets compared with the other groups. Results indicate that supplementing diets with 40 g SL/kg can improve growth and reproductive performance in L. vannamei female brooding specimens probably by enhancing LC-PUFA deposition and enhancing vitellogenin gene expression, as indicated by a greater abundance of mRNA transcript for vitellogenin, in the hepatopancreas.

BACKGROUND: The rice stem borer, Chilo suppressalis (Walker), is one of the most damaging rice pests in the world. The sublethal effects of chlorantraniliprole on development,reproduction and mRNA expression levels of vitellogenin gene (CsVg) in C. suppressalis were investigated.
RESULTS: Exposure of third-instar larvae to sublethal concentrations of chlorantraniliprole (LC10 and LC30 ) significantly extended larval duration, lowered the mean weight of male pupae and shortened male adult longevity. Pupal duration was significantly prolonged and the mean weight of female pupae was significantly lowered in the LC30 treatment group. While there were no significant sublethal effects on either the adult emergence rate or the egg hatch, the pupation rates in the LC10 treatment group (41.30%) and in the LC30 treatment group (23.98%) were significantly lower than the pupation rate of the control (71.86%), and LC10 and LC30 chlorantraniliprole significantly reduced fecundity, by 32.18 and 52.94% respectively. Furthermore, the expression levels of CsVg mRNA after exposure to LC10 and LC30 chlorantraniliprole significantly decreased, by 42.52 and 47.84% respectively, in 12-h-old female adults.
CONCLUSIONS: Sublethal concentrations of chlorantraniliprole adversely affect the development and reproduction of C. suppressalis. The downregulation of CsVg by chlorantraniliprole might have negative impacts on the fecundity of C. suppressalis. © 2016 Society of Chemical Industry.

In this study, the biologic effects of DES on the early life and adult life stages of Japanese medaka (Oryzias latipes) were evaluated. At the early life stage, the fertilized eggs were exposed to 1-1000 ng/L diethylstilbestrol (DES) for 15 days and the hatched larvae were continually exposed to the same concentrations for an additional 25 days. Significant adverse effects on hatchability, time to hatching and mortality rate occurred at DES concentrations of 100 and 1000 ng/L, while the abnormality (scoliosis and abdominal swelling) rate was significantly increased at 10 ng/L and above. After exposure, the fish were maintained in charcoal-dechlorinated tap water for a further 30 days. Only the male gonadosomatic index (GSI) at 1000 ng/L was significantly increased. At concentrations greater than 1 ng/L, estrogen receptor α (ERα) mRNA in both sexes and vitellogenin-I (Vtg-I) mRNA in males were significantly down-regulated; while Vtg-I mRNA in females was significantly up-regulated. When sexually mature medaka were exposed to 10 and 1000 ng/L DES for 21 days, only the GSI in females was significantly decreased at 1000 ng/L. At 10 and 1000 ng/L, ERα mRNA in both sexes was significantly down-regulated, while Vtg-I mRNA in males was significantly up-regulated. These findings showed that DES at the environmental concentration of 10 ng/L can affect the early life stage development of medaka and alter liver ERα and Vtg-I gene expression. Therefore, if we only focused on these sensitive toxicity endpoints such as ERα and Vtg-I mRNA expression, DES has a strong estrogenic effect on Japanese medaka.

Vitellogenin (Vg), an egg yolk precursor protein, not only functions as a source of nutrients and a nonpolar molecular carrier that combine and transfer lipids, proteins, vitamin and carotenoids to oocytes during the oogenesis. but also links with the immune defense in many oviparous animals. To investigate whether Vg plays a immune defensive role in noble scallop Chlamys nobilis, an acute Vibrio anguillarum infection experiment was conducted in orange and brown scallops with different carotenoids content. qRT-PCR result showed that Vg transcripts were significantly up-regulated after challenge with V. anguillarum in orange and brown shell scallops compared to the control group and Vg expression reached the highest spot at 6 h, indicated that Vg possessed an immune function in the noble scallop. Interestingly, a significantly positive correlation between Vg transcript levels and total carotenoids content in the ovary was observed, indicating that Vg gene expression was up regulated by carotenoids. The results suggest that Vg is a potent immune protector and carotenoid may linked with Vg plays an important role in host immune system against pathogens in noble scallop C. nobilis.

In this study, we cloned a full-length cDNA encoding vitellogenin (Vg) in the Fujian oyster Crassostrea angulata. The complete Vg cDNA consists of 5160 nucleotides with a long open reading frame encoding 1641 amino acid residues. The deduced amino acid sequence shared high similarity with the Vgs of other mollusc, fish, nematode and arthropod species, particularly in the N-terminal region. We analyzed the spatiotemporal expression of caVg transcripts by Real-time Quantitative PCR. In common with other mollusc Vgs, the caVg gene was expressed primarily in the ovary, and the levels were 348 and 177 times higher in maturation and ripeness stages (P<0.01), respectively, than in the partially spent stage. There was negligible expression in male oysters. In situ hybridization analysis further localized caVg mRNA to the follicle cells (also named auxiliary cells) surrounding the oocytes in the ovary. Moreover, in vivo waterborne exposure experiments in early gametogenesis oysters showed that estradiol-17β (E2) administration resulted in a significant increase in caVg mRNA expression. We conclude that caVg is synthesized in the follicle cell surrounding the vitellogenic oocyte in C. angulata, and directly passed to oocytes through the extracellular space without mediation through hemolymph. Also, we hypothesize that this process is mediated by E2 in a dose dependent.

The growth, development, and ERα and Vtg-I gene expressions of Japanese ricefish (Oryzias latipes; medaka) exposed to different concentrations of estriol (E3), including one environmentally relevant concentration, during embryo-adult life stages were evaluated. At the early life stage, fertilized eggs were exposed to 5, 50, 500, 5000ng/L E3 for 15days, and the hatched fry were exposed continuously to the same concentrations for an additional 15days. Exposure to 500 and 5000ng/L E3 resulted in adverse effects on hatchability and time to hatching. At 5000ng/L, the gross abnormality rate was increased and the number of females that hatched was twice that of males. When the fish were exposed to 5-5000ng/L E3 for further 60days, the male hepatosomatic index (HSI) was increased at 5000ng/L. The female gonadosomatic index (GSI) was decreased at 500 and 5000ng/L E3, while the male GSI at 5000ng/L E3 was increased and sex reversal was also found at this concentration. Quantitative RT-PCR showed that the hepatic vitellogenin-I (Vtg-I) genes were up-regulated in females at 500 and 5000ng/L E3 and in males at all E3 concentrations, whereas E3 did not affect estrogen receptor α (ERα) mRNA transcription. These results showed that E3 at environmental concentration of 5ng/L has no adverse effects on growth and development of the Japanese medaka. However, in this study, if we only focused on Vtg gene change in males, E3 had strong estrogenic effects on male medaka under the conditions of these experiments.

The fertilized eggs of Japanese medaka (Oryzias latipes) were exposed to estrone (E1) at 5-5000 ng L(-1) for 15 d, and the hatched fry were exposed continuously to the same concentrations for the additional 15 d. Adverse effects on hatchability, time to hatching, and gross abnormalities occurred at 50 ng L(-1) or above. Then the fry were divided into a continual exposure group, and a water recovery group. When the fry were exposed to E1 for another 60 d, there was a decrease in the hepatosomatic index (HSI) of males and the influence disappeared in the water recovery group. The gonadosonatic index (GSI) of females at 500 ng L(-1) decreased significantly in another 60 d exposure. While the fry were maintained in dechlorinated tap water for 60 d, a significant decrease in female GSI was observed at 50 ng L(-1) or above. An increased GSI was found in males in both continual exposure and water recovery groups at all E1 treatments. Quantitative RT-PCR showed that vitellogenin-I (Vtg-I) gene expressions in the female liver were significantly down-regulated at 50 ng L(-1) in the continual exposure group, and at 500 ng L(-1) in the water recovery group, while male Vtg-I genes were significantly up-regulated for all E1 treatments. In addition, all E1 treatments caused sex reversal of males. These results suggest that E1 at 5 ng L(-1) or above have unrecoverable impacts on the gonadal growth and development of medaka, even if only early life stages were exposed to E1.