Intergenerational Effects of Sublethal Lambda-Cyhalothrin Exposure on Aphis gossypii Glover (Hemiptera: Aphididae) Reproduction and Development

Simple Summary Aphis gossypii Glover is a pervasive pest with a global presence, causing significant economic losses in agriculture. Lambda-cyhalothrin is a widely used pyrethroid insecticide. Former research has shown that numerous chemical insecticides have a sublethal effect on A. gossypii. However, the sublethal effect of lambda-cyhalothrin on A. gossypii remains unknown. This study examined the effects of a sublethal dose of lambda-cyhalothrin on A. gossypii by life tables and qPCR analysis. In conclusion, the results clarified the sublethal effect of lambda-cyhalothrin on A. gossypii and provided a theoretical foundation for the prudent utilization of insecticides to combat this pest and devise strategies for managing resistance. Abstract Aphis gossypii Glover, a widespread insect, presents a substantial danger to global agriculture. Lambda-cyhalothrin is a pyrethroid insecticide that has been widely studied for its effects on arthropods. Studies have reported that sublethal doses of insecticides can produce various consequences on arthropod reproduction. Hence, the objective of this research was to examine the potential effects of a sublethal dose of lambda-cyhalothrin (LC30, 1.15 mg/L) on A. gossypii, for which we created life tables and conducted qPCR analysis. Adult longevity, fecundity, net reproductive rate (R0), body length, width, weight, and the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes were not significantly altered by lambda-cyhalothrin treatment at LC30 concentration in the F0 generation of A. gossypii adults. The intrinsic rate of increase (r) and finite rates of increase (λ) decreased significantly, while the mean generation time (T) increased. In addition, Vg and VgR gene expression levels were significantly higher in the F1 and F2 generations, whereas body length, width, and weight were notably reduced. The developmental duration, longevity, r, and λ did not differ significantly from those of the control group. Thus, the sublethal and intergenerational stimulatory effects of lambda-cyhalothrin were observed in A. gossypii, and the alterations in Vg and VgR in A. gossypii were strongly associated with sublethal effects. The results of this research offer valuable knowledge regarding the indirect impacts of lambda-cyhalothrin on A. gossypii, which can be utilized as a theoretical foundation for the prudent utilization of insecticides to combat this pest and devise strategies for managing resistance.


Introduction
Aphis gossypii Glover (Hemiptera: Aphididae), a pest with piercing-sucking mouthparts, is a global threat to a wide range of hosts and causes considerable economic losses in agriculture [1,2].At present, the main approach for managing this pest is the use of chemical control.However, due to the widespread utilization of chemical insecticides, A. gossypii has acquired resistance to organophosphates [3], neonicotinoids [4], pyrethroids [5], and various other insecticides.Additionally, the sublethal doses of insecticides can stimulate A. gossypii populations over multiple generations, a phenomenon known as intergenerational Insects 2024, 15, 173 3 of 13

Experimental Materials
A. gossypii were procured from the Institute of Cotton Research of CAAS (Anyang, China) and reared for more than 10 generations on cotton leaves (CCRI 49) in a laboratorycontrolled environment that maintained a constant temperature of 25 ± 1 • C and relative humidity of 65 ± 5%, with a 14 h light/10 h dark cycle, without any exposure to insecticides.

Experimental Method 2.2.1. Toxicity of Lambda-Cyhalothrin to A. gossypii
The toxicity of lambda-cyhalothrin to A. gossypii was determined using the FAOrecommended aphid dip test [32].For the pesticide treatment groups, lambda-cyhalothrin was dissolved in acetone and diluted with 0.01% Triton X-100 to create seven concentration gradients (128, 64, 32, 16, 8, 4, and 2 mg/L).The solution containing the same concentration of acetone and 0.01% Triton X-100 was used as a control.Healthy, wingless A. gossypii adults were selected and immersed in the drug liquid for 5 s before being removed and surface dried.The treated insects were then placed on fresh cotton leaves in 1.8% agar Petri dishes with 30 heads per concentration and four biological replicates.The Petri dishes were covered with paper towels underneath the lid to prevent insects from escaping.After 48 h, the number of deaths of the test insects was recorded and the mortality rate was calculated.Subsequently, all treated insects were placed in an incubator for feeding.

Life Table Construction
Initially, adult wingless A. gossypii was placed in 1.8% agar Petri dishes containing fresh cotton leaves.The adult aphids were taken out after 24 h, and the newborn nymphs were collected and fed for 5 d to reach the adult stage as the F 0 generation.According to the results of biological test, the treatment group was exposed to a solution of LC 30 lambdacyhalothrin, whereas the control group was exposed to 0.01% Triton X-100 containing the corresponding concentration of acetone.The F 0 generation of A. gossypii adult (<24 h) was immersed in the treatment and control groups for 5 s each, respectively.After drying the drug liquid, the insects were transferred onto the fresh cotton leaves in 1.8% agar Petri dishes.They were fed one head on each leaf, with a paper towel underneath the lid of the Petri dish to prevent them from escaping.Subsequently, the growth status of the insects was monitored every 24 h, and the number of offspring and deaths were recorded.Newborn aphids produced in the F 0 generation were used as the F 1 generation, and those produced in the F 1 generation were used as the F 2 generation, which continued to be fed in a Petri dish with a single head.Their life table data were recorded until all test insects died.Ninety biological replicates were used for each treatment.While recording the life table data, the body length and body width of adult aphids of each generation were photographed and measured for 48 h using an electron microscope (Sz61, Olympus Corporation, Tokyo, Japan).The body weights of the aphids were measured using an analytical balance (XS205DU, Mettler Toledo, Zurich, Switzerland).At least 30 aphids were measured for each treatment group.All the A. gossypii used in the test were placed in an incubator.The experiment involved replacing the leaves and Petri dishes every 2-3 days.

Sample Collection, Total RNA Extraction, and cDNA Library Construction
A. gossypii adults (48 h) in the F 0 -F 2 generations treatment groups and the control group were collected separately in the RNase-free centrifuge tubes.Each treatment was replicated three times, and at least 50 A. gossypii adults were collected from each.The samples were cryogenically preserved in liquid nitrogen and kept in a freezer at −80 • C for the purpose of extracting RNA.
Total RNA from adult insects was extracted using TRIzol reagent (Invitrogen, Carlsbad, CA, USA), and the quality of the RNA was assessed using a spectrophotometer (Nanodrop2000c, Thermo Scientific, Waltham, MA, USA).
The cDNA synthesis was carried out using the MonScript TM 5×RTIII All-in-One Mix kit (Monad Biotech Co., Ltd., Wuhan, China) according to the manufacturer's instructions, with the extracted RNA (1 µL) serving as a template.The synthesized cDNA was diluted 20 times and stored at −20 • C.

Quantitative Real-Time PCR
RT-qPCR was conducted on a StepOnePlus™ Real-Time PCR System (CFX Opus 96; Bio-Rad, Singapore).The qPCR reaction system was synthesized according to the instructions provided for MonAmp TM SYBR ® Green qPCR Mix (Monad Biotech Co., Ltd., Wuhan, China).The reactions included 10 µL qPCR Mix, 1 µL cDNA, 0.4 µL primer F/R, and Nuclease-Free Water added to 20 µL.The reaction program was set as follows: 95 • C for 30 s, 40 cycles of 95 • C for 10 s, and 60 • C for 30 s. Three mechanical and three technical replicates were used for each treatment.The β-actin of A. gossypii was used as an internal reference gene, and the primer sequences of genes Vg and VgR were designed as described by Ma et al. [33] and Wang et al. [34] (Table S1).The primers were synthesized by Sangon Biotech Co., Ltd.(Shanghai, China).The relative expression of Vg and VgR was calculated by Livak and Schmittgen [35]'s 2 −∆∆Ct method.

Data Analysis
To calculate the virulence regression formula, raw test data were analyzed using the PROBIT model [36] in IBM SPSS Statistics 20.0 (IBM, Chicago, IL, USA), from which the LC 30 and 95% confidence interval for sublethal concentrations were calculated.Additionally, the significance of body length, width, and weight measurements, as well as the qPCR results of A. gossypii, were assessed through the utilization of analysis of variance (ANOVA) and Student's t-test.
To calculate the developmental time of each stage, longevity, fecundity, net reproductive rate (R 0 ), intrinsic rate of increase (r), finite rate of increase (λ), mean generation time (T), age-stage specific survival rate (S xj ), age-specific survival rate (l x ), age-specific fecundity (m x ), age-specific maternity (l x m x ), age-stage specific life expectancy (e xj ), age-stage reproductive value (v xj ), and other life table parameters of A. gossypii, raw life table data were processed using TWOSEX-MSChart (http://140.120.197.173/Ecology/,accessed on 12 August 2022) [37][38][39][40].In addition, the bootstrap technique was used with 100,000 random resampling tests to determine the mean and SE of life table parameters, and the paired bootstrap method was used to analyze the significant differences between the treatment group and the control group [41,42].

Toxicity of Lambda-Cyhalothrin to A. gossypii
As depicted in Table 1 and Figure S1, the LC 30 , LC 50 , and LC 90 values for adult A. gossypii exposed to lambda-cyhalothrin for 48 h were 1.15, 4.29, and 105.94 mg/L, respectively.The corresponding 95% confidence intervals were 0.47-2.04,2.52-6.26,and 63.02-236.87mg/L, respectively.Adult longevity was not significantly different between the LC 30 lambda-cyhalothrin treated control group and the F 0 generation of A. gossypii (Figure 1A).And the fecundity was slightly lower in the treatment group, but the difference was not statistically significant (Figure 1D).

Effect of a Sublethal Concentration of Lambda-Cyhalothrin on the Growth and Development of F0 Generation of A. gossypii
Adult longevity was not significantly different between the LC30 lambda-cyhalothrin treated control group and the F0 generation of A. gossypii (Figure 1A).And the fecundity was slightly lower in the treatment group, but the difference was not statistically significant (Figure 1D).There was also a difference between the sublethal doses of lambda-cyhalothrin and control group in terms of A. gossypii generation F0 population growth parameters was also observed.After treatment, both the r and λ were markedly lower in the treatment group, and the T was significantly prolonged.However, the R0 difference is not significant (Table 2).There was also a difference between the sublethal doses of lambda-cyhalothrin and control group in terms of A. gossypii generation F 0 population growth parameters was also observed.After treatment, both the r and λ were markedly lower in the treatment group, and the T was significantly prolonged.However, the R 0 difference is not significant (Table 2).The S xj curve of the F 0 generation of A. gossypii in the treatment group exhibited a similar decreasing trend to the control (Figure 2A).This indicated that the survival rate of A. gossypii was minimally affected by the LC 30 of lambda-cyhalothrin.The m x curves showed a rise at first, then a decline, reaching a peak at the age of 4 days (6.68 offspring) for the LC 30 treatment and at the age of 3 days (6.00 offspring) in the control.Notably, LC 30 treatment group had a higher peak fecundity than that of the control group (Figure 2B).The v xj curves exhibited an initial rise followed by a decline over time, with both the treatment and control groups reaching their peak of reproduction values at 3 days (13.36 and 13.23 offspring, respectively) (Figure 2C).Adult life expectancy was 11.89 days in the treatment group and 12.08 days in the control (Figure 2D).
The Sxj curve of the F0 generation of A. gossypii in the treatment group exhibited a similar decreasing trend to the control (Figure 2A).This indicated that the survival rate of A. gossypii was minimally affected by the LC30 of lambda-cyhalothrin.The mx curves showed a rise at first, then a decline, reaching a peak at the age of 4 days (6.68 offspring) for the LC30 treatment and at the age of 3 days (6.00 offspring) in the control.Notably, LC30 treatment group had a higher peak fecundity than that of the control group (Figure 2B).The vxj curves exhibited an initial rise followed by a decline over time, with both the treatment and control groups reaching their peak of reproduction values at 3 days (13.36 and 13.23 offspring, respectively) (Figure 2C).Adult life expectancy was 11.89 days in the treatment group and 12.08 days in the control (Figure 2D).There were no significant differences in body length, width, or weight between the treatment and control cohorts (Figure 3).There were no significant differences in body length, width, or weight between the treatment and control cohorts (Figure 3).
The Sxj curve of the F0 generation of A. gossypii in the treatment group exhibited a similar decreasing trend to the control (Figure 2A).This indicated that the survival rate of A. gossypii was minimally affected by the LC30 of lambda-cyhalothrin.The mx curves showed a rise at first, then a decline, reaching a peak at the age of 4 days (6.68 offspring) for the LC30 treatment and at the age of 3 days (6.00 offspring) in the control.Notably, LC30 treatment group had a higher peak fecundity than that of the control group (Figure 2B).The vxj curves exhibited an initial rise followed by a decline over time, with both the treatment and control groups reaching their peak of reproduction values at 3 days (13.36 and 13.23 offspring, respectively) (Figure 2C).Adult life expectancy was 11.89 days in the treatment group and 12.08 days in the control (Figure 2D).There were no significant differences in body length, width, or weight between the treatment and control cohorts (Figure 3).

Effects of a Sublethal Concentration of Lambda-Cyhalothrin on the Growth and Development of F 1 Generation of A. gossypii
A. gossypii' s F 1 generation development was not significantly different from that of the control group in LC 30 lambda-cyhalothrin treatment (Figures 1B and S2A).However, there was a significant difference between the treatment and control groups in terms of fecundity (Figure 1D).
Although the control group exhibited no significant differences in r, λ, and T, the R 0 of the F 1 generation of A. gossypii in the LC 30 lambda-cyhalothrin treatment exhibited a significant increase (Table 3).The S xj curves of F 1 generation of A. gossypii in the treatment group overlapped with the S xj curves of the control group (Figure 4A,B).This suggested that the survival rate of the F 1 generation in the treatment group was almost the same as that of the control group at any stage.Likewise, the l x curves of the experimental group almost overlapped with the control group.The m x curves showed a rise at first, then a decline, with the treatment group reaching its peak at 6 days old (6.02 offspring), and the control group showing a peak at 7 days old (5.93 offspring) (Figure 4C,D).The v xj curves (Figure 4E,F) showed a significant increase in reproductive values after reaching adulthood, followed by a decline, as the fecundity decreased.In both treatment and control groups, peak reproductive values were observed on the sixth day, with values of 14.78 and 14.01 offspring, respectively.Notably, the peaks and timing of peak occurrence were similar.The life expectancy of the treatment and control groups were 17.12 and 17.21 days, respectively (Figure 4G,H).
A. gossypii F 1 generation body length, width, and weight were significantly lower than those of the control group in the treatment group (Figure 3).   A. gossypii F1 generation body length, width, and weight were significantly than those of the control group in the treatment group (Figure 3).

Effects of a Sublethal Concentration of Lambda-Cyhalothrin on the Growth and Deve of F2 Generation of A. gossypii
The development of each stage of the F2 generation of A. gossypii in the tre group was similar to that in the control (Figures 1C and S2B), whereas fecundity w nificantly higher (Figure 1D).
The population growth parameters of F2 generation of A. gossypii are shown i 3. The R0, r, and λ in the LC30-treated F2 generation of A. gossypii were not signi different from those of the control, but the T was markedly prolonged.
The Sxj curve of the F2 generation of A. gossypii treated with LC30 lambda-cyha almost overlapped with that of the control group (Figure 5A,B).This indicates t

Effects of a Sublethal Concentration of Lambda-Cyhalothrin on the Growth and Development of F 2 Generation of A. gossypii
The development of each stage of the F 2 generation of A. gossypii in the treatment group was similar to that in the control (Figures 1C and S2B), whereas fecundity was significantly higher (Figure 1D).
The population growth parameters of F 2 generation of A. gossypii are shown in Table 3.The R 0 , r, and λ in the LC 30 -treated F 2 generation of A. gossypii were not significantly different from those of the control, but the T was markedly prolonged.
The S xj curve of the F 2 generation of A. gossypii treated with LC 30 lambda-cyhalothrin almost overlapped with that of the control group (Figure 5A,B).This indicates that the survival rate of the treatment group at each stage is the same as that of the control group.Additionally, the comparison between the control group and the treatment group showed similar l x curves, whereas the m x curves initially increased and then decreased.The treatment group and the control group both reached their peak at 8 days of age (4.85 and 5.14 offspring, respectively) (Figure 5C,D).Furthermore, the v xj curves indicated a substantial rise in the reproductive values of both the treatment and control groups upon reaching adulthood, followed by a subsequent decline coinciding with a decrease in fecundity.The groups reached their peak reproductive values at the age of 7 days (11.56 offspring) and 6 days (12.05 offspring), respectively (Figure 5E,F).Additionally, the life expectancy of the treatment and control groups were 17.72 and 17.07 days, respectively (Figure 5G,H).
The body length, width, and weight of the F 2 generation of A. gossypii in the LC 30 lambda-cyhalothrin treatment were significantly reduced compared to those of the control (Figure 3).rise in the reproductive values of both the treatment and control groups upon r adulthood, followed by a subsequent decline coinciding with a decrease in fecund groups reached their peak reproductive values at the age of 7 days (11.56 offsprin days (12.05 offspring), respectively (Figure 5E,F).Additionally, the life expectanc treatment and control groups were 17.72 and 17.07 days, respectively (Figure 5G, The body length, width, and weight of the F2 generation of A. gossypii in t lambda-cyhalothrin treatment were significantly reduced compared to those of the (Figure 3).

Effect of a Sublethal Concentration of Lambda-Cyhalothrin on the Expression Level of A. gossypii Vg and VgR
Vg and VgR gene expression in F 0 -F 2 generations of A. gossypii treated with LC 30 lambda-cyhalothrin is shown in Figure 6.A significant difference was not found between the treatment and control groups in the relative expression levels of the Vg and VgR genes, whereas Vg and VgR gene expression was significantly elevated in the F 1 and F 2 generations treatment groups compared with that of controls.

Effect of a Sublethal Concentration of Lambda-Cyhalothrin on the Expression Level of A. gossypii Vg and VgR
Vg and VgR gene expression in F0-F2 generations of A. gossypii treated with LC30 lambda-cyhalothrin is shown in Figure 6.A significant difference was not found between the treatment and control groups in the relative expression levels of the Vg and VgR genes, whereas Vg and VgR gene expression was significantly elevated in the F1 and F2 generations treatment groups compared with that of controls.
In this study, the treatment of the F0 generation of A. gossypii with LC30 of lambdacyhalothrin resulted in a decrease in fecundity and R0, although these differences were statistically insignificant compared to the control.Additionally, a significant reduction in r and λ and a pronounced prolongation in T were observed.It is possible that A. gossypii adapted to the stress of lambda-cyhalothrin to improve survival by reducing the reproductive ability, indicating that lambda-cyhalothrin at LC30 can inhibit the reproduction of A. gossypii in the F0 generation, aligning with the research of Wang et al. [6].However, flupyradifurone at concentrations LC10 and LC25 significantly increased the adult longevity and fecundity of A. gossypii [49], which could be attributed to the varying sublethal impacts of distinct insecticides on A. gossypii.
In this study, the F1 and F2 generations of A. gossypii showed a reduction in body length, width, and weight, as well as a significant increase in fecundity, after treatment with LC30 of lambda-cyhalothrin, indicating that the sublethal concentration of lambdacyhalothrin had a positive impact on their reproductive capacity.Similarly, sulfoxaflor [50] at LC20, decamethrin at LC30, and imidacloprid [51] at LC30 increased the fecundity of F1 Myzus persicae, whereas imidacloprid [52] and acetamiprid [53] at LC15 increased the fecundity of F1 A. gossypii.This could be due to a disruption in physiological equilibrium caused by insecticide stress in the F0 generation, which inhibited F0 reproduction.Additionally, the embryos in the abdomen of the F0 generation of A. gossypii absorbed a small amount of lambda-cyhalothrin from their mothers [6].The F1 generation then increased its reproduction rate through the overcompensation effect, and the body length, width, and weight were significantly reduced.Moreover, with the superposition of generations, this effect continued throughout the F2 generation.This aligns with the discoveries made by Shang et al. [9].In contrast, treating A. gossypii with buprofezin significantly reduced the R0, r, λ, and total fecundity, as well as significantly increased the mean generation time
In this study, the treatment of the F 0 generation of A. gossypii with LC 30 of lambdacyhalothrin resulted in a decrease in fecundity and R 0 , although these differences were statistically insignificant compared to the control.Additionally, a significant reduction in r and λ and a pronounced prolongation in T were observed.It is possible that A. gossypii adapted to the stress of lambda-cyhalothrin to improve survival by reducing the reproductive ability, indicating that lambda-cyhalothrin at LC 30 can inhibit the reproduction of A. gossypii in the F 0 generation, aligning with the research of Wang et al. [6].However, flupyradifurone at concentrations LC 10 and LC 25 significantly increased the adult longevity and fecundity of A. gossypii [49], which could be attributed to the varying sublethal impacts of distinct insecticides on A. gossypii.
In this study, the F 1 and F 2 generations of A. gossypii showed a reduction in body length, width, and weight, as well as a significant increase in fecundity, after treatment with LC 30 of lambda-cyhalothrin, indicating that the sublethal concentration of lambdacyhalothrin had a positive impact on their reproductive capacity.Similarly, sulfoxaflor [50] at LC 20 , decamethrin at LC 30 , and imidacloprid [51] at LC 30 increased the fecundity of F 1 Myzus persicae, whereas imidacloprid [52] and acetamiprid [53] at LC 15 increased the fecundity of F 1 A. gossypii.This could be due to a disruption in physiological equilibrium caused by insecticide stress in the F 0 generation, which inhibited F 0 reproduction.Additionally, the embryos in the abdomen of the F 0 generation of A. gossypii absorbed a small amount of lambda-cyhalothrin from their mothers [6].The F 1 generation then increased its reproduction rate through the overcompensation effect, and the body length, width, and weight were significantly reduced.Moreover, with the superposition of generations, this effect continued throughout the F 2 generation.This aligns with the discoveries made by Shang et al. [9].In contrast, treating A. gossypii with buprofezin significantly reduced the R 0 , r, λ, and total fecundity, as well as significantly increased the mean generation time in the F 1 generation [54].It is hypothesized that differences in chemical insecticide types, exposure modes, and exposure times led to some variation in the outcomes of the aforementioned studies.
The Vg and VgR are frequently used to assess the fecundity of female insects.The expression levels of the insect Vg and VgR genes have been shown to be affected by sublethal doses of insecticides.The RT-qPCR analysis in this study revealed that Vg and VgR gene expression levels were not significantly different in the F 0 generation of A. gossypii.F 1 and F 2 generation A. gossypii showed significantly increased expression of the Vg and VgR genes, in line with the results of studies on A. gossypii treated with the sublethal concentrations of acetamiprids [53].Therefore, lambda-cyhalothrin did not induce the expression of the Vg and VgR genes in the F 0 generation of A. gossypii.However, the expression of Vg and VgR genes in F 1 and F 2 generations of A. gossypii can be stimulated in alternate generations, which improves their fecundity and allows them to adapt to lambda-cyhalothrin stress.
In summary, the offspring of A. gossypii exposed to sublethal doses of lambda-cyhalothrin will re-emerge.On the one hand, lambda-cyhalothrin has a stimulating effect on the reproduction of A. gossypii, and on the other hand, that lambda-cyhalothrin may develop resistance to A. gossypii.Therefore, it is difficult to control A. gossypii.We speculate that this should also be one of the reasons for the current decrease in the amount of pyrethroid pesticides.This study provides a theoretical basis for the rational use of pesticides in the field.

Conclusions
In this study, the sublethal and intergenerational effects of lambda-cyhalothrin exposure on A. gossypii were investigated using a life table and qPCR.The results showed that the sublethal doses of lambda-cyhalothrin inhibited the reproduction of the parental generation of A. gossypii but enhanced the reproductive potential of the subsequent generations (F 1 and F 2 ).Furthermore, the changes in Vg and VgR of A. gossypii may be closely related to its sublethal effects.Therefore, the purpose of this study is to provide a theoretical foundation for the effective use of pesticides in the control of A. gossypii, as well as for the development of strategies to manage resistance to pesticides.

Figure 1 .
Figure 1.Developmental duration (A,B,C) and fecundity (D) of F0-F2 generations of A. gossypii treated with LC30 of lambda-cyhalothrin.Means ± SE in the same row followed by the same lowercase letters represent significant differences between treatments using a paired bootstrap test (ns denotes insignificance, * denotes p-value less than 0.05, and ** denotes p-value less than 0.01).

Figure 1 .
Figure 1.Developmental duration (A-C) and fecundity (D) of F 0 -F 2 generations of A. gossypii treated with LC 30 of lambda-cyhalothrin.Means ± SE in the same row followed by the same lowercase letters represent significant differences between treatments using a paired bootstrap test (ns denotes insignificance, * denotes p-value less than 0.05, and ** denotes p-value less than 0.01).

Figure 3 .
Figure 3. Body length (A), body width (B), and body weight (C) of F0-F2 generation of A. gossypii treated with sublethal concentration of lambda-cyhalothrin.The Student's t-test is used for significance analysis (ns denotes insignificance, * denotes p-value less than 0.05, and *** denotes p-value less than 0.005).All error bars indicate ±SE.

Figure 2 .
Figure 2. Age-stage specific survival rate (S xj ) (A), age-specific fecundity (m x ) (B), age-stage reproductive value (v xj ) (C), and age-stage specific life expectancy (e xj ) (D) of F 0 generation of A. gossypii treated with LC 30 of lambda-cyhalothrin.

Figure 3 .
Figure 3. Body length (A), body width (B), and body weight (C) of F0-F2 generation of A. gossypii treated with sublethal concentration of lambda-cyhalothrin.The Student's t-test is used for significance analysis (ns denotes insignificance, * denotes p-value less than 0.05, and *** denotes p-value less than 0.005).All error bars indicate ±SE.

Figure 3 .
Figure 3. Body length (A), body width (B), and body weight (C) of F 0 -F 2 generation of A. gossypii treated with sublethal concentration of lambda-cyhalothrin.The Student's t-test is used for significance analysis (ns denotes insignificance, * denotes p-value less than 0.05, and *** denotes p-value less than 0.005).All error bars indicate ±SE.

Insects 2024 ,
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Figure 4 .
Figure 4. Age-stage specific survival rate (S xj ) (A,B), age-specific survival rate (l x ), age-specific fecundity (m x ), age-specific maternity (l x m x ) (C,D), age-stage reproductive value (v xj ) (E,F), and age-stage specific life expectancy (e xj ) (G,H) of F 1 generation of A. gossypii treated with LC 30 of lambda-cyhalothrin.

Figure 5 .
Figure 5. Age-stage specific survival rate (S xj ) (A,B), age-specific survival rate (l x ), age-specific fecundity (m x ), age-specific maternity (l x m x ) (C,D), age-stage reproductive value (v xj ) (E,F), and age-stage specific life expectancy (e xj ) (G,H) of F 2 generation of A. gossypii treated with LC 30 of lambda-cyhalothrin.

Figure 6 .
Figure 6.Relative expression level of Vg (A) and VgR (B) in F0-F2 generations of A. gossypii.The Student's t-test is used for significance analysis (ns denotes insignificance, * denotes p-value less than 0.05, and *** denotes p-value less than 0.005).All error bars indicate ±SE.

Figure 6 .
Figure 6.Relative expression level of Vg (A) and VgR (B) in F 0 -F 2 generations of A. gossypii.The Student's t-test is used for significance analysis (ns denotes insignificance, * denotes p-value less than 0.05, and *** denotes p-value less than 0.005).All error bars indicate ±SE.

N a Slope ± SE b LC 30 (mg/L) (95%CL) c LC 50 (mg/L) (95%CL) LC 90 (mg/L) (95%CL)
Effect of a Sublethal Concentration of Lambda-Cyhalothrin on the Growth and Development of F 0 Generation of A. gossypii
Note: a number of A. gossypii adults; b standard error; c 95% confidence limits; and d Chi-square value (χ 2 ).

Table 2 .
Population growth parameters of F0 generation of A. gossypii exposed to LC30 of lambdacyhalothrin.

Table 2 .
Population growth parameters of F 0 generation of A. gossypii exposed to LC 30 of lambdacyhalothrin.

Table 3 .
Population growth parameters of F 1 -F 2 generation of A. gossypii treated with sublethal concentration of lambda-cyhalothrin.R 0 , net reproductive rate (offspring/female); r, intrinsic rate of increase (d −1 ); λ, finite rate of increase (d −1 ); and T, mean generation time (d).The table displays the means ± SE. Note: