Bioaccumulation of Cadmium Affects Development, Mating Behavior, and Fecundity in the Asian Corn Borer, Ostrinia furnacalis

Changes in the Biology and Susceptibility of Weevil (Cylas formicarius) to the Insecticide Spinetoram as a Response to Cadmium Contamination

The sweet potato weevil Cylas formicarius is a notorious underground pest in sweet potato (Ipomoea batatas L.). However, little is known about the effects of cadmium (Cd) stress on weevil biology and resistance to pesticides and biotic agents. Therefore, we fed sweet potato weevils with Cd-contaminated sweet potato and assessed adult food intake and survival and larval developmental duration and mortality rates, as well as resistance to the insecticide spinetoram and susceptibility to the entomopathogenic fungus Beauveria bassiana. With increasing Cd concentration, the number of adult weevil feeding holes, adult survival and life span, and larval developmental duration decreased significantly, whereas larval mortality rates increased significantly. However, at the lowest Cd concentration (30 mg/L), adult feeding was stimulated. Resistance of adult sweet potato weevils to spinetoram increased at low Cd concentration, whereas Cd contamination did not affect sensitivity to B. bassiana. Thus, Cd contamination affected sweet potato weevil biology and resistance, and further studies will investigate weevil Cd accumulation and detoxification mechanisms.

Necrophagous flies as bioindicators in Cd and Zn co-contaminated areas of Tak Province, Thailand

Necrophagous flies may be effective bioindicators of chemical substances within polluted locations, as they are sensitive to environmental changes, have large populations, and thrive in a single location over their lifespan. Diversity and abundance of necrophagous flies were determined at livestock farms contaminated with potentially toxic elements (PTEs) in Tak Province and Nakhon Sawan Province, Thailand. Substantial soil zinc (Zn) concentrations (> 1100 mg kg-1) were detected at a cattle farm at Khaothong, Nakhon Sawan Province, and soil cadmium (Cd) values were significantly elevated (> 3 mg kg-1) at a cattle farm in Pha De, Tak Province. Anthropogenic inputs including Zn mining, domestic wastewater, and certain materials used in local agriculture were point sources of PTEs at the livestock farms in the Pha De and Khaothong subdistricts. Lower temperatures and humidity during the rainy season may have resulted in increased numbers of necrophagous flies, which was 1.5 times greater compared to the dry season. However, the dry season exhibited a higher PTE buildup in fly tissue. The order of important value index (IVI) values of the necrophagous flies were: Chrysomya megacephala (56.80), Musca domestica (27.21), C. rufifacies (25.40) and Sarcophaga spp. (17.54), respectively. These necrophagous flies may play a significant role in PTE-contaminated ecosystems based on their high IVI values, suggesting that they could be used as bioindicators of PTEs. Principal component analysis (PCA) results for necrophagous flies associated with each sampling site during the dry season were consistent with flies having substantial IVI values. Musca domestica and C. megacephala of both sexes displayed substantial correlations with Cr, Al, and Mn, while females of Sarcophaga spp. displayed strong associations with Cd. At the cattle farm in Khaothong, males of M. domestica showed a significant relationship with Zn, Cu, Pb, and Ni. When considering PTE accumulation capacity in flies commonly found at field sites, C. megacephala and M. domestica are the most suitable bioindicators of PTEs. This study confirms that necrophagous flies serve as reliable bioindicators of PTE pollution.

Effects of undesired substances and their bioaccumulation on the black soldier fly larvae, Hermetia illucens (Diptera: Stratiomyidae)-a literature review

Black soldier fly (BSF), Hermetia illucens (L.) (Diptera: Stratiomyidae), is predominantly reared on organic wastes and other unused complementary substrates. However, BSF may have a buildup of undesired substances in their body. The contamination of undesired substance, e.g., heavy metals, mycotoxins, and pesticides, in BSF mainly occurred during the feeding process in the larval stage. Yet, the pattern of accumulated contaminants in the bodies of BSF larvae (BSFL) is varied distinctively depending on the diets as well as the contaminant types and concentrations. Heavy metals, including cadmium, copper, arsenic, and lead, were reported to have accumulated in BSFL. In most cases, the cadmium, arsenic, and lead concentration in BSFL exceeded the recommended standard for heavy metals occurring in feed and food. Following the results concerning the accumulation of the undesired substance in BSFL's body, they did not affect the biological parameters of BSFL, unless the amounts of heavy metals in their diets are highly exceeding their thresholds. Meanwhile, a study on the fate of pesticides and mycotoxins in BSFL indicates that no bioaccumulation was detected for any of the target substances. In addition, dioxins, PCBs, PAHs, and pharmaceuticals did not accumulate in BSFL in the few existing studies. However, future studies are needed to assess the long-term effects of the aforementioned undesired substances on the demographic traits of BSF and to develop appropriate waste management technology. Since the end products of BSFL that are contaminated pose a threat to both human and animal health, their nutrition and production process must be well managed to create end products with a low contamination level to achieve a closed food cycle of BSF as animal feed.

Susceptibility of Hyphantria cunea larvae to Beauveria bassiana under Cd Stress: An integrated study of innate immunity and energy metabolism

Biological control is widely used for integrated pest management. However, there are many abiotic factors that can affect the biocontrol efficiency. In this study, we investigated the susceptibility of Hyphantria cunea larvae to Beauveria bassiana under Cd stress, and the corresponding mechanism was analyzed around innate immunity and energy metabolism. The results showed that mortality of H. cunea larvae treated with Cd and B. bassiana was significantly higher than those treated with B. bassiana alone, and the combined lethal effect exhibited a synergistic effect. Compared with the single fungal treatment group, the total hemocyte count in the combined Cd and fungal treatment group decreased significantly, accompanied by a decrease in phagocytosis, encapsulation, and melanization activity. The expression levels of three phagocytosis-related genes, one encapsulation-promoting gene, and one melanization-regulating gene were significantly lower in the combined treatment group than those in the single fungal treatment group. Furthermore, pathogen recognition ability, signal transduction level, and immune effector expression level were weaker in the combined treatment group than those in the single fungal treatment group. The expression levels of 14 key metabolites and 7 key regulatory genes in glycolysis and tricarboxylic acid cycle pathways were significantly lower in the combined treatment group than those in the single fungal treatment group. Taken together, the weakness of innate immunity and energy metabolism in response to pathogen infection resulted in an increased susceptibility of H. cunea larvae to B. bassiana under Cd pre-exposure. Microbial insecticide is a preferred strategy for pest control in heavy metal-polluted areas. AVAILABILITY OF DATA AND MATERIAL: All the data that support the findings of this study are available in the manuscript.

Cadmium exposure-triggered growth retardation in Hyphantria cunea larvae involves disturbances in food utilization and energy metabolism

Serious environmental pollution in the ecosystem makes phytophagous insects face a great risk of exposure to pollutants, especially heavy metals. This study aims to understand the effects of Cd exposure on the growth and development of Hyphantria cunea and to elucidate the mechanism of growth toxicity induced by Cd from the perspective of food utilization and energy metabolism. Our results showed that the larval basal growth data, growth index, fitness index, and standard growth index were significantly decreased after feeding on Cd-containing artificial diets. The Cd-treated larvae had significantly higher digestibility than the untreated larvae. However, the food consumption, efficiency of conversion of digested food, and efficiency of conversion of ingested food were significantly lower than those of untreated larvae. Eight key metabolites in the glycolysis pathway and six key metabolites in the tricarboxylic acid cycle pathway were significantly reduced in Cd-treated larvae. The mRNA expression levels of two regulatory genes (6-phosphofructokinase 1 and hexokinase-1) belonging to two key enzymes in the glycolysis pathway and four regulatory genes (isocitrate dehydrogenase-1, isocitrate dehydrogenase-3, citrate synthase, and oxoglutarate dehydrogenase) belonging to three key enzymes in the tricarboxylic acid cycle pathway were significantly lower in the Cd-treated group than in the control group. Furthermore, most fitness-related traits were significantly and positively correlated with food utilization (except approximate digestibility) or energy metabolism parameters. Taken together, Cd exposure-triggered growth retardation of H. cunea larvae is a consequence of disturbances in food utilization and energy metabolism, thereby emphasizing the toxicity of heavy metals.

The susceptibility of Hyphantria cunea larvae to microbial pesticides Bacillus thuringiensis and Mamestra brassicae nuclear polyhedrosis virus under Cd stress

Heavy metal pollution is an abiotic factor that can affect the efficiency of pest control. In this study, two microbial pesticides, Bacillus thuringiensis and Mamestra brassicae nuclear polyhedrosis virus (MbNPV), were used to treat Hyphantria cunea larvae with Cd pre-exposure, and the humoral and cellular immunity of H. cunea larvae with Cd exposure were evaluated. The results showed that Cd exposure increased the susceptibility of H. cunea larvae to microbial pesticides B. thuringiensis and MbNPV, and the lethal effect of Cd exposure and microbial pesticides on H. cunea larvae was synergistic. Cd exposure significantly decreased the expression of pathogen recognition genes (GNBP1 and GNBP3), signal transduction genes (Relish, Myd88, Tube, and Imd), and antimicrobial peptide gene (Lebocin) in the humoral immunity of H. cunea larvae compared with the untreated larvae. Parameters of cellular immunity, including the number of hemocytes, phagocytic activity, melanization activity, encapsulation activity, and the expression of three phagocytic regulatory genes (HEM1, GALE1, GALE2), were also found to decrease significantly in Cd-treated larvae. TOPSIS analysis showed that humoral immunity, cellular immunity, and total immunity levels of H. cunea larvae with Cd exposure were weaker than those in untreated larvae. Correlation analysis showed that the mortality of two microbial pesticides investigated in H. cunea larvae was negatively correlated with the humoral and cellular immunity of larvae. Taken togther, Cd exposure results in immunotoxic effects on H. cunea larvae and the use of microbial pesticides are an effective strategy for pest control in heavy metal-polluted areas.

Effects of wildfire ashes on aquatic invertebrates: First molecular approach on Chironomus riparius larvae

The wildfire magnification in recent years has raised increasing concern about their adverse impacts on the environment. Wildfires are recognized as an important source of diffuse pollution for the nearby aquatic systems being potentially toxic to aquatic life. Albeit previous studies with wildfire runoff/ashes observed effects in aquatic organisms, to date, different severity origins of ashes and their impact at the sub-organismal level on aquatic biota have not been assessed. In this work, the molecular response of Chironomus riparius exposed to wildfire with low (LS) and high (HS) severity ashes from burnt Pine plantations was evaluated by employing an array of 42 genes related to crucial metabolic pathways by Real time-PCR. IV instar larvae were exposed for 72 h to aqueous extract of ashes (12.5 %, 25 %, 50 %, 75 % and 100 %) prepared from LS and HS ashes. Mn, Zn, and Pb were the metals found at highest concentration in both ash extracts, for HS notable Cd, Mn and Cr presence. From the 42 genes studied only 4 were not altered (22 genes modulated their response by LS and 38 genes in the case of HS) showing the opposite response at 100% with downregulated by LS and upregulated by HS. The 12.5 %, 25 %, 100 % HS and 25 % LS were the main modulators, confirmed by the integrative biomarkers response (IBR). Remarkable genotoxicity was generated by ashes even activating the apoptosis response, and endocrine disruption observed could modify the development. Moreover, detoxification and stress response were strongly activated, limiting the organism's future response to external aggressions. The employment of this novelty approach with molecular tools act as early alarm signal preventing greater damages. Overall, wildfire ashes showed to be a significant environmental disruptor to C. riparius even at lower concentration and the short exposure time employed, emphasizing the strong impact of wildfires on aquatic systems.

The Effect of Different Heavy Metals on the Development of Lucilia sericata (Diptera: Calliphoridae)

This study investigates the impacts of three different heavy metals at different concentrations on some life-history traits of Lucilia sericata (Meigen 1826) (Diptera: Calliphoridae). First-instar larvae of L. sericata were reared on a diet containing four concentrations (0.25, 0.50, 1, and 2 µg/g) of the heavy metals (cadmium, zinc copper). The parameters measured were larval and pupal mortality, larval length, adult, pupal, and larval weight, and development time. Larval and pupal survival decreased as heavy metal concentrations increased. Pupal weight was significantly different among heavy metals andc oncentrations, but the adult weight was not significantly different among heavy metals and concentrations. The larval length was significantly different among concentrations and heavy metals. This study reveals that the presence of heavy metal in carrion or the carrion environment should be inconsidered when estimating the time of colonization in forensic investigations.

Starvation and cadmium affect energy reserves and oxidative stress in individuals of Spodoptera exigua

Different factors, such as starvation and metal exposure, may affect development and cause oxidative stress in insects. Some host plants may contain a high concentration of cadmium due to their hyperaccumulating property. The negative effects of metals and hunger may be manifested by low availability of energetic substrates. This study aimed to assess whether the insect population with a history of long metal exposure may better manage metal stress or/and starvation at different developmental stages, with the use of energetic substrates. Two strains of Spodoptera exigua model organism were tested: control strain and cadmium strain (treated continuously for over 200 generations with subtoxic amounts of cadmium). The effects of different factors, individually and in combination, on the tested strains were assessed, first by determining the body weight of larvae and pupae and then by estimating the concentration of biomolecules (proteins, carbohydrates, lipids, or glycogen) in the 4th and 5th larval stages and in pupae, and the total antioxidant capacity and lipid peroxidation level in the 4th larval stage. Compared to control strain, cadmium strain individuals exhibited changes in the concentration of soluble carbohydrates and protein. This was partly related to earlier 1-day starvation. In particular, changes in carbohydrate concentration seemed to be a sensitive biomarker of metal stress, independent of the age of individuals and period of starvation. However, the increase in the total antioxidant capacity and the concentration of lipid peroxidation products in the 4th larval stage under the effect of cadmium was dependent on strain origin.

Toxic metals that interact with thiol groups and alteration in insect behavior

Toxic metals, such as mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu), are widespread in the biosphere, and human activities have contributed to their continuous release into the ecosystems. Metal-induced toxicity has been extensively studied in mammals; however, the effects of these metals on insects' behavior have been explored to far lesser degree. As the main mechanism of toxicity, the cationic metals, explored in this review, have high affinity for thiol-containing molecules, disrupting the function of several proteins and low-molecular-weight thiol-containing molecules. Existing literature has corroborated that Hg, Pb, Cd, and Cu can disrupt locomotor and mating behaviors, but their effects on insects' memory and learning have yet to be fully characterized. Though field studies on metal-induced toxicity in insects are limited, results from Drosophila melanogaster as an experimental model suggest that insects living in contaminated environments can have behavioral foraging and reproductive deficits, which may cause population decline. In this review, we address the interaction between metals and endogenous thiol groups, with emphasis on alterations in insect behavior.

Identification of a metallothionein gene and the role of biological thiols in stress induced by short-term Cd exposure in Ostrinia nubilalis

Cadmium (Cd) is a non-essential metal that is highly toxic to all living forms, characterized by an extremely high affinity for thiol (SH) groups. The aim of this work was to identify and experimentally verify metallothionein gene and to analyze the role of biological thiols in stress induced by short-term Cd exposure in Ostrinia nubilalis, one of the most important corn pests. The coding region of a metallothionein (MT) gene in O. nubilalis was identified, encoding protein, OnMT1, which contains 46 amino acids, including 12 cysteine residues, and has no aromatic amino acids. Phylogenetic analysis revealed that OnMT1 clustered together with metallothionein from Bombyx mori. Structural bioinformatics analysis strongly suggests that OnMT1 is a metallothionein with affinity for multiple transition metals. Further, in order to elucidate the role of biological thiols, O. nubilalis L5 larvae were exposed to increasing Cd concentrations in diet (6.85, 41.71, 77.35 mg kg^-1) during a 48 h period, after which Cd concentration in larvae was measured (3.50, 12.02, 47.37 mg kg^-1, respectively). Due to short-term Cd exposure, concentration of free protein SH groups and relative expression of OnMT1 and thioredoxin (Trx) genes was elevated, while the reduced glutathione content remained unchanged. The presented results provide evidence that OnMT1 plays a role in Cd detoxification and homeostasis, and confirm the importance of biological thiols, especially OnMT1 and Trx, in the early response of O. nubilalis to Cd poisoning, indicating interaction between Cd and thiol-linked redox reactions. Insects provide valuable insight into molecular adaptations to metals.

The effects of cadmium on the development of Drosophila and its transgenerational inheritance effects

A new focus in toxicology research is the impact of parental exposure to environmental toxic substances on the characteristics of offspring. In the present study, newly produced eggs of Drosophila melanogaster were treated with different concentrations of cadmium (0, 1, 2, 4, 8 mg/kg) to study the effects of development. The results showed that cadmium changed the larval body length and weight, prolonged the pupation and eclosion time, and changed the relative expression levels of development-related genes (baz, β-Tub60D, tj). Furthermore, the parental Drosophila (F₀) were treated with cadmium (4.5 mg/kg) from egg stage, and when grows to adults, they mated in standard medium to produce the de-stressed offspring (F₁-F₄) to assess the transgenerational effects of developmental delay. The results showed that the delayed effects of the pupation and eclosion time could be maintained for two generations, and the inhibiting effects of juvenile hormone (JH) and ecdysone (20-hydroxyecdysone, 20E) could be maintained for two or three generations. More importantly, cadmium increased the expression of DNA methylation-related genes (dDnmt2, dMBD2/3) in the ovaries (F₀-F₂) and testicles (F₀ and F₁). In addition, cadmium accumulated in parental Drosophila (F₀) was not transmitted to offspring through reproductive pathway. These results demonstrate that the developmental toxicity caused by cadmium could be transmitted to the de-stressed offspring, and the observed transgenerational inheritance effects may be associated with epigenetic regulation, underscoring the need to consider fitness of future generations in evaluating the toxicity and environmental risks of cadmium.

The susceptibility of Lymantria dispar larvae to Beauveria bassiana under Cd stress: A multi-omics study

Insect susceptibility to entomopathogenic microorganisms under heavy metal stress, as well as its regulatory mechanism is still poorly understood. This study aims to investigate the susceptibility of gypsy moth larvae to Beauveria bassiana under cadmium (Cd) stress (at 3.248 or 44.473 mg Cd/kg fresh food), and reveal the potential molecular mechanisms underlying the Cd effect on the larval susceptibility to B. bassiana via combined transcriptome and proteome analyses. Our results showed that pre-exposure to Cd increased the susceptibility of gypsy moth larvae to B. bassiana, and there was an additive effect between Cd exposure and B. bassiana infection on the larval mortality. Under the Cd stress at low and high concentrations, 138 and 899 differentially expressed genes (DEGs), as well as 514 and 840 differentially expressed proteins (DEPs) were identified, respectively. Immunotoxic effects induced by Cd exposure at the transcription level increased in a negative dose-response manner, with no immunity-related DEGs obtained at the low Cd concentration and a high number of immunity-related DEGs down-regulated at the high Cd concentration. In contrast, a potentially suppressed or stimulated trend in the Toll and Imd signaling pathway at protein level was revealed under low or high concentration of Cd treatment. Analysis of xenobiotics biodegradation-related pathways at both transcription and translation levels revealed that the gypsy moth larvae possessed an efficient homeostasis regulatory mechanism to the low-level Cd exposure, but exhibited a reduced xenobiotics biodegradation capability to the Cd stress at high levels. Together, these findings demonstrate Cd contamination promote the microbial-based biocontrol efficacy, and unravel the molecular regulatory network of heavy metal exposures that affects susceptibility of insects to pathogenic diseases.

Transfer of heavy metal along food chain: a mini-review on insect susceptibility to entomopathogenic microorganisms under heavy metal stress

The development and physiological status of pest insects are important factors that affect the effectiveness of biological control. Current knowledge reveals that heavy metals can be transferred to phytophagous insects through food chains and cause various chronic toxicological effects on the growth and physiology of phytophagous insects. These findings potentially attribute heavy metal contamination to an environmental factor governing biocontrol efficiency against pest insects, pointing to an urgent demand to better understand the effects of heavy metal exposure on insect susceptibility to entomopathogenic microorganisms. Here we discuss the transfer characteristics of heavy metals along the food chains to phytophagous insects and conclude that heavy metal exposure may promote insect susceptibility to entomopathogenic microorganisms in the heavy metal-contaminated regions. Furthermore, we propose a 'combined effect' hypothesis that combination of entomopathogenic agent and heavy metal stress can cause a much higher overall insect mortality than does the entomopathogenic agent or the heavy metal stress alone. This is a new and relatively unexplored area in the microbial-based biocontrol research, which might have great potential for future optimization of biocontrol strategies against economically and ecologically important agricultural or forest pests in the heavy metal polluted areas. © 2020 Society of Chemical Industry.

Puparial Cases as Toxicological Indicators: Bioaccumulation of Cadmium and Thallium in the Forensically Important Blowfly Lucilia sericata

In this study, we present entomotoxicological data on the accumulation of cadmium and thallium in a forensically important blowfly, Lucilia sericata, and evaluate the reliability and utility of such information as toxicological evidence for poisoning as a cause of death. We observed that Cd and Tl content in different growing stages of L. sericata (larvae, puparial cases, and adults) was increasing with increasing metal concentration in the feeding substrate, namely metal-enriched liver. However, patterns of accumulation differed between the two metals investigated, showing a linear relationship for Cd and a saturable pattern for Tl. For cadmium, the highest bioaccumulation factor (BAF) was found in the larval stage (in the range of 0.20–0.25), while for thallium, puparial cases accumulated more metal than the other stages tested (BAF in the range of 0.24–0.42). Thallium was also observed to have a negative effect on larval growth, resulting in lower weight and smaller puparial size. With this study, we update the information on the bioaccumulation of cadmium in forensically important blowflies and provide the first report on the bioaccumulation of thallium as well as its developmental impact in blowflies. Specifically, our results suggest that analysis of puparial cases could yield useful information for entomotoxicological investigations. The content of Cd and Tl in larvae, puparial cases, and adults of L. sericata was determined by inductively coupled plasma mass spectrometry (ICP-MS). The validation parameters of the method such as sensitivity, detection limits, quantification limits, precision, and accuracy were evaluated. The method detection limit (MDL) for all types of samples was in the range of 1.6–3.4 ng g⁻¹ for Cd and 0.034–0.15 ng g⁻¹ for Tl, and the accuracy of the method was confirmed by a high recovery of metals from certified reference materials (91.3% for Cd and 94.3% for Tl).

Oxidative stress parameters, DNA damage and expression of HSP70 and MT in midgut of Trachyderma hispida (Forskål, 1775) (Coleoptera: Tenebrionidae) from a textile industry area

The textile mill industry is one of the major sources of pollution and contributors of metal contaminants to the environment. At the same time, the industry is important for global economy. Pollution caused by the textile industry is characteristic due to a unique set of potentially toxic substances. Darkling beetles (Coleoptera, Tenebrionidae), which live in all biogeographical regions, are especially common in soil quality and soil degradation studies. Our study was designed to assess long-term effects of textile industry (which generates specific pollution) on soil organisms, namely Trachyderma hispida. We especially wanted to find out what changes allow the species to survive and adapt to these specific conditions. Energy-dispersive X-ray spectroscopy of soil and midgut tissues of T. hispida sampled from a polluted site in the Edku textile industrial area in Egypt revealed a high accumulation of chemical elements, compared to a reference site. The concentration of elements in soil was well correlated with their concentration in the midgut of insects. Activity of superoxide dismutase, catalase, ascorbate peroxidase and glutathione S-transferase were negatively correlated with concentration of elements in soil and in the midgut. Meanwhile, malondialdehyde concentration in the midgut revealed an opposite tendency. DNA damage and expression of stress proteins, (HSP70 and metallothionein - MT) were elevated in insects from the polluted site. The activity of textile industry in the area of Edku undoubtedly causes an increase of soil pollution and, in consequence, causes a number of changes in the bodies of organisms living in these areas, including T. hispidus. Therefore, it is necessary to find a solution which limits the emission of waste from the textile industry, as well as to design modern strategies of processing, storing and utilizing it.

Effects of zinc acquired through the plant-aphid-ladybug food chain on the growth, development and fertility of Harmonia axyridis

Heavy metal pollution is an increasingly serious problem in agricultural ecosystems. Zinc accumulation in the food chain may harm the physiological functions of organisms, including herbivorous and predatory insects. Its effects on development and reproduction in Harmonia axyridis are largely unknown. In this study, five Zn solutions (25, 50, 100, and 150 mg/kg) plus control (0 mg/kg) were used to treat broad beans and to water the resulting seedlings. Aphids fed on these seedlings were eaten by H. axyridis ladybugs. Zn accumulation was found at all three trophic levels. Compared with the control group, ladybugs in the 25, 50, and 100 mg/kg groups had significantly reduced weight gain from the 4^th instar to adulthood. Pupae and larvae (instars 1-4) in the 150 mg/kg group had the lowest survival of any group; pupal mortality in the 100 mg/kg group was significantly higher than that in the control group. Under Zn stress, female adults had inhibited expression of Vg1, Vg2 and VgR, reducing egg production and hatchability. Zn thus negatively affected their fertility. These results provide a theoretical basis for future exploration of soil heavy metal pollution impacts in ecosystems.