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BACKGROUND: Lepidopteran pest control in agriculture has become heavily dependent on cultivars that express Bacillus thuringiensis (Bt) toxins as 'plant‐incorporated protectants'. However, populations of Spodoptera frugiperda (Smith) in Brazil appear resistant to the Bt traits currently available in commercial soybean cultivars. RESULTS: This study evaluated S. frugiperda life history when feeding on three different Bt soybean cultivars. Cultivars expressing Cry1Ac + Cry1F and Cry1A.105 + Cry2Ab2 + Cry1Ac Bt toxins caused 100% larval mortality in S. frugiperda. Both non‐Bt and Cry1Ac‐expressing soybean induced transgenerational effects that increased the survival of subsequent generations. A Cry1Ac soybean diet reduced the generation time (T) of S. frugiperda relative to non‐Bt soybean, resulting in shorter generation time and more rapid population growth. CONCLUSION: The implications of these results revealed how diet can alter aspects of insect life history and biology, and have important implications for sustainable management of S. frugiperda on soybean. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The impact of warming on zooxanthellate corals is widespread, from tropical to temperate seas, with its associated mortalities causing global concern. The temperate coral Cladocora caespitosa is the only zooxanthellate coral with reef building capacity in the Mediterranean Sea, a climate change hotspot with warming rates triple the global average. During the past two decades, C. caespitosa populations have suffered severe mortality events associated with marine heatwaves (MHWs). However, with monitoring efforts beginning, at best, in the 2000s, the occurrence of MHWs before that period, as well as the sublethal effects of these events remain poorly understood. Here, we use sclerochronology to reconstruct the histories of past stress events and long‐term sublethal effects on C. caespitosa in three locations along a latitudinal gradient within the NW Mediterranean Sea, each with different environmental conditions. Skeletal extension, density and calcification rates were compared with the in situ seawater temperature of each site to assess their relationship. Furthermore, we assessed the occurrence of skeletal growth anomalies to reconstruct stress events between 1991 and 2021, a period that encompasses the onset and evolution of warming‐related mass mortality events in the NW Mediterranean Sea. Our results reveal a positive association between calcification and temperature, following a latitudinal temperature gradient. However, the evolution of the likelihood distribution of growth rates in the warmest site (Columbretes Islands) since the 1990s indicates a decrease in linear extension and calcification rates during the most recent years. With the increase in the frequency of MHWs and growth anomalies during the last decade, this decline suggests recurrent physiological stress events. These results unravel information on the long‐term impacts of warming on coral growth and highlight the potential of applying sclerochronology to reconstruct the sublethal effects of warming using C. caespitosa. [ABSTRACT FROM AUTHOR]

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 (λCy) could induce severe reproductive toxicity in the lacewing, Chrysoperla sinica (Tjeder), but the toxicological mechanism remains unclear. This study discovered that λCy 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, λCy inhibits CsILP expression, leading to disorder of ISP, leading to the reduced fecundity of C. sinica. [ABSTRACT FROM AUTHOR]

Imidacloprid and other neonicotinoid insecticides severely impact the performance and survival of honey bees and other pollinators. In the present study, we focused on the gene expression profile of newly emerged Apis mellifera queen bees after sublethal imidacloprid treatment during the larval stage. Royal jelly containing 1 ppb imidacloprid was provided to larvae for 3 consecutive days (2–4 days postemergence). Queen larvae treated with imidacloprid showed lower capping and emergence rates (35.5% and 24.22%, respectively) than did control larvae (61.68% and 52.95%, respectively), indicating a high failure rate of queen rearing associated with imidacloprid exposure during the larval stage. The molecular response to imidacloprid treatment was examined next. By comparing the gene expression profiles of imidacloprid‐treated queen larvae and those of control queen larvae using DESeq2, we identified 215 differentially expressed genes, with 105 and 111 up‐ and downregulated genes, respectively. Gene Ontology results indicated that chitin binding– and calcium ion binding–related genes were upregulated, while phototransduction‐ and visual perception–related genes were downregulated. The high mortality rate and altered gene expression profiles suggest that treatment with even 1 ppb imidacloprid can severely impact queen bee survival. Environ Toxicol Chem 2024;43:2232–2242. © 2024 SETAC [ABSTRACT FROM AUTHOR]

We compared the effects of lambda‐cyhalothrin as the pure active ingredient and as a formulated product (Zero®), on the larval stage of the autochthonous species Boana pulchella. We evaluated ecotoxicological endpoints, behavioral and developmental alterations, and the biochemical detoxifying, neurotoxic, and oxidative stress responses, covering a wide concentration range from environmental to high application levels. Both pyrethroid preparations displayed similar ecotoxicity (median lethal concentration of ~0.5 mg/L), with the lethal effect of Zero® being more pronounced than that of the active ingredient. Sublethal behavioral alterations in natatory activity were observed at 1000 times lower concentrations, indicating the ecological hazard of tadpole exposure to this pyrethroid at environmentally relevant concentrations. Biochemical endpoints in B. pulchella larvae showed significant responses to lambda‐cyhalothrin in the ng/L range; these responses were different for the pure or the formulated product, and they were variable at higher concentrations. Principal components analysis confirmed the prevalence of biochemical responses as early endpoints at the lowest lambda‐cyhalothrin concentrations; the Integrated Biomarker Response Index proportionally increased with pyrethroid concentration in a similar way for the pure and the formulated products. We conclude that lambda‐cyhalothrin is of concern from an environmental perspective, with particular emphasis on autochthonous anuran development. The battery of biochemical biomarkers included in our study showed a consistent integrated biomarker response, indicating that this is a potent tool for monitoring impacts on amphibians. Environ Toxicol Chem 2024;43:2134–2144. © 2024 SETAC [ABSTRACT FROM AUTHOR]

The predatory bug Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae) is an important biological control agent for planthoppers, such as Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), and leafhoppers in rice fields (Oryza sativa L., Poaceae). In this study, the sublethal effects of azoxystrobin and difenoconazole, two fungicides extensively used in rice production, on this predatory bug were investigated. The results indicated that exposure to the two fungicides at the third instar had no influence on developmental duration, but difenoconazole resulted in a 25.2% decrease in the lifespan of adult males. When exposed as newly emerged adults, azoxystrobin caused a 33.5% decrease in female longevity. The pre‐oviposition period of azoxystrobin‐treated females mating with azoxystrobin‐treated males was shortened by 44.9%, compared with the control, whereas the pre‐oviposition period of difenoconazole‐treated females mating with control males was lengthened by 32.2% compared with the control group. However, the two fungicides had no effect on fecundity and egg hatchability. Furthermore, the two fungicides did not impact the average consumption of C. lividipennis of N. lugens individuals. They did stimulate the response of C. lividipennis males to rice plants infested by N. lugens in a two‐choice H‐shaped olfactometer test. Also, the predatory capacity of C. lividipennis males was increased after exposure to difenoconazole, whereas the predatory capacity of females was decreased after exposure to the two fungicides. Overall, our results indicated that azoxystrobin and difenoconazole pose no notable risk to C. lividipennis. These findings establish a foundation for the rational and coordinated utilization of fungicides and biological control agents in rice ecosystems. [ABSTRACT FROM AUTHOR]

Background: G1 strain Ganaspis brasiliensis (Ihering) has been recently released in both Europe and America as a biological control agent of the spotted wing drosophila, Drosophila suzukii (Matsumura). In initial phases of classical biological control programs, it becomes imperative to evaluate the susceptibility of parasitoids to insecticides, to identify the best alternatives to adopt in an integrated pest management and organic perspective. In this study, we evaluated lethal and sublethal effects of topical application of five different insecticides classes: neonicotinoids, diamides, pyrethroids, organophosphates and spinosyns. Additionally, we tested residual toxicity in field trials in vineyards and sweet cherry orchards. Results: Adult wasps' susceptibility to different insecticides' classes were consistent between laboratory and field. Spinosad exhibited the highest toxicity, with a median lethal concentration (LC50) of 0.00372 of the maximum field dose, and the highest knock‐down effect in field trials, causing 92.5 ± 5% of mortality at T0. λ‐cyhalothrin showed sublethal effects on both male and female insects' longevity when applied at LC30. In field trials, deltamethrin showed the highest persistence, causing significant parasitoid mortality up to 14 days after treatment. Conversely, cyantraniliprole was the least toxic active ingredient according to both topical and residual bioassays, even though its residues caused mortality up to 7 days after the treatment in the field. Conclusion: Our results indicate that spinosad and λ‐cyhalothrin are highly toxic to G. brasiliensis, making them incompatible with classical biological control programs. Cyantraniliprole exhibited lower toxicity, and may be considered a selective pesticide for the integrated management of D. suzukii. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Deltamethrin, as a highly effective and broad‐spectrum insecticide, has been widely used for agricultural pest control such as Aphis gossypii worldwide. Increasing evidence has shown that despite great economic benefits brought by it, deltamethrin has also non‐negligible side effects. However, the potential risks and related molecular mechanisms remain largely unclear. Results: Herein, the life table parameters and transcriptome sequencing analyses of the four successive aphid generations were performed to investigate the hormesis and transgenerational effects of deltamethrin on A. gossypii. The life table analysis showed that although the exposure of G0 aphid to 30% lethal concentration (LC30) deltamethrin significantly reduced the net reproduction rate (R0), intrinsic rate of increase (r), and fecundity of G0, but it significantly enhanced the R0 and fecundity of subsequent two generations (G1 and G2) of A. gossypii. Moreover, transcriptomic analyses showed that the signaling pathways related to posttranscriptional regulation (spliceosome), protein processing, longevity regulating, and cell proliferation (DNA replication, homologous recombination and non‐homologous end‐joining) were significantly up‐regulated in G1 or G2 under LC30 deltamethrin treatment. Additionally, we also found that the deltamethrin–sulfoxaflor rotation of G0 and G1 still induced reproductive stimulation, but the reproductive stimulation induced by insecticides rotation treatment was significantly lower than that in the deltamethrin exposure alone. Conclusion: Our study demonstrates that sublethal concentrations of deltamethrin significantly enhanced the offspring fecundity of cotton aphid. In addition, our study also reveals the transcriptional response mechanism of hormesis‐induced fecundity increase, providing valuable reference for optimizing the application of deltamethrin in integrated pest management. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

As climate change intensifies heatwaves, quantifying associated mortality within ectothermic populations is crucial for effective conservation. Thermal tolerance landscape (TTL) models are useful predictive tools that assume exponentially decreasing survival durations in individuals with increasing temperatures. This assumption has been validated through regression analyses on data from constant temperature experiments, primarily focusing on adult‐stage individuals. However, this approach does not allow for direct model validation with data from dynamic, real‐world heatwave events and overlooks early recruitment stage vulnerabilities.This study aimed to address these gaps using the blue mussel Mytilus, a foundation species forming extensive reefs along temperate coasts, as a model organism. We monitored survival rates of mussels (juveniles and adults) under constant heatwave (CHW) conditions in a laboratory experiment and under dynamic heatwave (DHW) scenarios simulated in an outdoor mesocosm experiment. Post‐heatwaves, we also assessed recruitment rates within the mesocosms. TTL models were parametrised by employing Approximate Bayesian Computation with Sequential Monte Carlo (ABC‐SMC) on each dataset separately.The parameter distributions were similar across both experiments, and the ABC‐SMC model predictions closely matched the observed survival declines, validating these models. In comparison, we found a lower predictive performance when using a Bayesian regression approach. Additionally, our best‐fit model predicted that warming across the non‐fatal DHW regimes would increase sublethal effects on mussels. The observed impact on the recruitment stage was more pronounced, with the recruitment rate following an exponential decay as sublethal effects increased. Our model projected minor (<4%) sublethal effects in adult mussels during the century's five warmest summer temperature regimes, corresponding to 0%–32% declines in recruitment rates.Our research extends the TTL model validation, demonstrates the resilience of subtidal Baltic Mytilus to future extreme heatwaves and offers an approach to predict heatwave‐induced population mortalities, applicable to other species and sensitive systems. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

To date, studies of the impacts of climate warming on individuals and populations have mostly focused on mortality and thermal tolerance. In contrast, much less is known about the consequences of sublethal effects, which are more challenging to detect, particularly in wild species with cryptic life histories. This necessitates the development of molecular tools to identify their signatures. In a split‐clutch field experiment, we relocated clutches of wild, nesting loggerhead sea turtles (Caretta caretta) to an in situ hatchery. Eggs were then split into two sub‐clutches and incubated under shallow or deep conditions, with those in the shallow treatment experiencing significantly higher temperatures in otherwise natural conditions. Although no difference in hatching success was observed between treatments, hatchlings from the shallow, warmer treatment had different length–mass relationships and were weaker at locomotion tests than their siblings incubated in the deep, cooler treatment. To characterise the molecular signatures of these thermal effects, we performed whole genome bisulfite sequencing on blood samples collected upon emergence. We identified 287 differentially methylated sites between hatchlings from different treatments, including on genes with neurodevelopmental, cytoskeletal, and lipid metabolism functions. Taken together, our results show that higher incubation temperatures induce sublethal effects in hatchlings, which are reflected in their DNA methylation status at identified sites. These sites could be used as biomarkers of thermal stress, especially if they are retained across life stages. Overall, this study suggests that global warming reduces hatchling fitness, which has implications for dispersal capacity and ultimately a population's adaptive potential. Conservation efforts for these endangered species and similar climate‐threatened taxa will therefore benefit from strategies for monitoring and mitigating exposure to temperatures that induce sublethal effects. [ABSTRACT FROM AUTHOR]

Chagas disease is considered one of the most important human parasitosis in the United States. This disease is mainly transmitted by insects of the subfamily Triatominae. The chemical vector control is the main tool for reducing the incidence of the disease. However, the presence of triatomines after pyrethroids spraying has been reported in some regions, as in the case of Triatoma infestans in Argentina and Bolivia. The presence of insects can be explained by the colonization from neighbouring areas, the reduction of insecticide dose to sublethal levels due to environmental factors, and/or by the evolution of insecticide resistance. In the last two scenarios, a proportion of the insects is not killed by insecticide and gives rise to residual populations. This article focuses on the toxicological processes associated with these scenarios in triatomines. Sublethal doses may have different effects on insect biology, that is, sublethal effects, which may contribute to the control. In addition, for insect disease vectors, sublethal doses could have negative effects on disease transmission. The study of sublethal effects in triatomines has focused primarily on the sequence of symptoms associated with nervous intoxication. However, the effects of sublethal doses on excretion, reproduction and morphology have also been studied. Rhodnius prolixus and T. infestans and pyrethroids insecticides were the triatomine species and insecticides, respectively, mainly studied. Insecticide resistance is an evolutionary phenomenon in which the insecticide acts as a selective force, concentrating on the insect population's pre‐existing traits that confer resistance. This leads to a reduction in the susceptibility to the insecticide, which was previously effective in controlling this species. The evolution of resistance in triatomines received little attention before the 2000s, but after the detection of the first focus of resistance associated with chemical control failures in T. infestans from Argentina in 2002, the study of resistance increased remarkably. A significant number of works have studied the geographical distribution, the resistance mechanisms, the biological modifications associated with resistance, the environmental influences and the genetic of T. infestans resistant to pyrethroid insecticides. Currently, studies of insecticide resistance are gradually being extended to other areas and other species. The aim of this article was to review the knowledge on both phenomena (sublethal effects and insecticide resistance) in triatomines. For a better understanding of this article, some concepts and processes related to insect‐insecticide interactions, individual and population toxicology and evolutionary biology are briefly reviewed. Finally, possible future lines of research in triatomine toxicology are discussed. [ABSTRACT FROM AUTHOR]

Continued use and development of new insecticides are seen as a necessary part of modern agriculture, but insecticides, even at sublethal levels, may also affect beneficial non‐target species, such as pollinators, predators, and parasitic wasps. Here, we studied sublethal effects of four insecticides – acetamiprid, dimethoate, flupyradifurone, and sulfoxaflor – all targeting cholinergic neurons in insects, on sexual communication and olfactory host finding in the parasitic wasp Lariophagus distinguendus (Förster) (Hymenoptera: Pteromalidae). We found that all four insecticides reduced, at least at one of the tested sublethal doses, pheromone‐mediated courtship behaviour (wing fanning) in males and the mating frequency of treated wasps. Treated females no longer preferred host‐associated kairomones. This suggests that the olfactory sense of the wasps is hampered by sublethal insecticide doses. The lowest bioactive doses tested in the bioassays were 0.021 ng for sulfoxaflor and 0.105 ng for acetamiprid, dimethoate, and flupyradifurone. These low amounts are field realistic and might be taken up by the wasps, e.g., by feeding contaminated plant nectar. Exposure to these compounds likely compromises the important ecosystem service provided by parasitic wasps as natural enemies in terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mating is an essential factor that governs the size of insect populations that reproduce sexually. The extensive application of insecticides has both lethal and sublethal effects on the physiology and mating behavior of insect natural enemies. The predatory bug Cyrtorhinus lividipennis is a natural enemy of planthopper and leafhopper populations in the rice ecosystem. Unfortunately, the effects of insecticides on the mating behavior of C. lividipennis are not well‐understood. RESULTS: The mating behavior of C. livdipennis consisted of mounting, antennal touch and mating attempts, genital insertion, adjustment of posture, and separation of the mating pair. Approximately 82.5% of the C. lividipennis mating pairs displayed their first mating at 12–36 h postemergence. Mating activity occurred throughout a 24‐h period, with peak activity at 12:00–14:00 h, and the mean duration of mating was 48.75 min. Sublethal exposure to imidacloprid increased mating latency. Compared with the controls, the duration of courtship, pre‐mating and adjusting posture for males treated with imidacloprid were prolonged. The duration of mating for females treated with imidacloprid was prolonged relative to untreated controls. The fecundity and daily spawning capacity of females treated with imidacloprid were higher than the untreated controls. CONCLUSION: Our results provide insight into the mating process of C. lividipennis. Imidacloprid prolonged the duration of mating, which may explain the enhanced reproductive output in C. lividipennis females treated with imidacloprid. These findings will be useful in both rearing C. lividipennis and deploying this natural enemy in rice fields. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aboveground oligolectic bee, Heriades truncorum, is a particularly good model for studying the impact of pesticides on sexual communication, since some aspects of its mating behavior have previously been described. We have tested (1) the interference of the pesticide flupyradifurone on male precopulatory behavior and male mating partner preferences, (2) the way that the pesticide interferes in male quality assessment by the female, and (3) the effects of the pesticide on the chemical compounds in the female cuticle. We exposed bees of both sexes to a sublethal concentration of flupyradifurone. Various behaviors were registered in a mating arena with two females (one unexposed and one exposed) and one male (either unexposed or exposed). Unexposed males were quicker to attempt to mate. Treatment also impacted precopulatory behavior and male quality assessment by females. Males approached unexposed females more quickly than insecticide‐exposed ones. Females exposed to insecticide produced lower amounts of some cuticular hydrocarbons (sex pheromone candidates) and appeared less choosy than unexposed females. Our findings suggest that insecticide exposure affects sexual communication, playing a role both in male preference and in male quality assessment by the female. [ABSTRACT FROM AUTHOR]

The integration of untargeted lipidomics approaches in ecotoxicology has emerged as a strategy to enhance the comprehensiveness of environmental risk assessment. Although current toxicity tests with soil microarthropods focus on species performance, that is, growth, reproduction, and survival, understanding the mechanisms of toxicity across all levels of biological organization, from molecule to community is essential for informed decision‐making. Our study focused on the impacts of sublethal concentrations of the insecticide teflubenzuron on the springtail Folsomia candida. Untargeted lipidomics was applied to link changes in growth, reproduction, and the overall stress response with lipid profile changes over various exposure durations. The accumulation of teflubenzuron in organisms exposed to the highest test concentration (0.035 mg a.s. kg–1 soil dry wt) significantly impacted reproductive output without compromising growth. The results suggested a resource allocation shift from reproduction to size maintenance. This hypothesis was supported by lipid shifts on day 7, at which point reductions in triacylglycerol and diacylglycerol content corresponded with decreased offspring production on day 21. The hypermetabolism of fatty acids and N‐acylethanolamines on days 2 and 7 of exposure indicated oxidative stress and inflammation in the animals in response to teflubenzuron bioaccumulation, as measured using high‐performance liquid chromatography–tandem mass spectrometry. Overall, the changes in lipid profiles in comparison with phenotypic adverse outcomes highlight the potential of lipid analysis as an early‐warning tool for reproductive disturbances caused by pesticides in F. candida. Environ Toxicol Chem 2024;43:1149–1160. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

BACKGROUND: The stingless bee, Trigona spinipes, is an important pollinator of numerous native and cultivated plants. Trigona spinipes populations can be negatively impacted by insecticides commonly used for pest control in crops. However, this species has been neglected in toxicological studies. Here we observed the effects of seven insecticides on the survival of bees that had fed directly on insecticide‐contaminated food sources or received insecticides via trophallactic exchanges between nestmates. The effects of insecticides on flight behavior were also determined for the compounds considered to be of low toxicity. RESULTS: Imidacloprid, spinosad and malathion were categorized as highly toxic to T. spinipes, whereas lambda‐cyhalothrin, methomyl and chlorfenapyr were of medium to low toxicity and interfered with two aspects of flight behavior evaluated here. Chlorantraniliprole was the only insecticide tested here that had no significant effect on T. spinipes survival, although it did interfere with one aspect of flight capacity. A single bee that had ingested malathion, spinosad or imidacloprid, could contaminate three, four and nineteen other bees, respectively via trophallaxis, resulting in the death of the recipients. CONCLUSION: This is the first study to evaluate the ecotoxicology of a range of insecticides that not only negatively affected T. spinipes survival, but also interfered with flight capacity, a very important aspect of pollination behavior. The toxicity of the insecticides was observed following direct ingestion and also via trophallactic exchanges between nestmates, highlighting the possibility of lethal effects of these insecticides spreading throughout the colony, reducing the survival of non‐foraging individuals. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Bumblebees are important pollinators in both natural and agricultural ecosystems, but their survival and pollination service are threatened by extensive pesticide use. Due to regulation changes, acetamiprid has become the only neonicotinoid substance that can be used without restrictions and in open‐field cultivations in the European Union. Yet, we know little about how this active ingredient affects bumblebees' foraging behaviour and if such effects are similarly detrimental to those of other neonicotinoids. Here we investigated how a 14‐day‐long (chronic) exposure to low (5 ppb) and high (2500 ppb) concentrations of acetamiprid in syrup affected different aspects of foraging behaviour in buff‐tailed bumblebees (Bombus terrestris, Linnaeus). We recorded individual foraging at artificial food patches during one‐hour‐long trials and then compared several foraging‐related measures between differently dosed individuals. We found that 75.12% of the total syrup consumption occurred at the first‐exploited patch, but individuals did not exhibit any bias toward pesticide‐treated food patches. Chronic exposure to acetamiprid had little effect on individual foraging decisions at the first‐exploited food patch but significantly affected the time to the first feeding and the number of feedings at the second‐exploited patch in interaction with body mass. The duration of the first feeding was affected only by foragers' body mass. Our finding indicates that chronic exposure to a high but field‐realistic concentration of acetamiprid may alter some aspects of bumblebees' foraging behaviour. If such behavioural changes accumulate during consecutive foraging bouts, chronic exposure to this pesticide might lead to a reduction of daily resource collection, ultimately jeopardising colony fitness or plant (crop) pollination. [ABSTRACT FROM AUTHOR]

Lethal and sublethal effects of pesticides on nontarget organisms are one of the causes of the current decline of many insect species. However, research in the past decades has focused primarily on pollinators, although other beneficial nontarget organisms such as parasitic wasps may also be affected. We studied the sublethal effects of the four insecticides acetamiprid, dimethoate, flupyradifurone, and sulfoxaflor on pheromone‐mediated sexual communication and olfactory host finding of the parasitic wasp Nasonia vitripennis. All agents target cholinergic neurons, which are involved in the processing of chemical information by insects. We applied insecticide doses topically and tested the response of treated wasps to sex pheromones and host‐associated chemical cues. In addition, we investigated the mating rate of insecticide‐treated wasps. The pheromone response of females surviving insecticide treatment was disrupted by acetamiprid (≥0.63 ng), dimethoate (≥0.105 ng), and flupyradifurone (≥21 ng), whereas sulfoxaflor had no significant effects at the tested doses. Olfactory host finding was affected by all insecticides (acetamiprid ≥1.05 ng, dimethoate ≥0.105 ng, flupyradifurone ≥5.25 ng, sulfoxaflor ≥0.52 ng). Remarkably, females treated with ≥0.21 ng dimethoate even avoided host odor. The mating rate of treated N. vitripennis couples was decreased by acetamiprid (6.3 ng), flupyradifurone (≥2.63 ng), and sulfoxaflor (2.63 ng), whereas dimethoate showed only minor effects. Finally, we determined the amount of artificial nectar consumed by N. vitripennis females within 48 h. Considering this amount (∼2 µL) and the maximum concentrations of the insecticides reported in nectar, tested doses can be considered field‐realistic. Our results suggest that exposure of parasitic wasps to field‐realistic doses of insecticides targeting the cholinergic system reduces their effectiveness as natural enemies by impairing the olfactory sense. Environ Toxicol Chem 2023;42:2400–2411. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

The bird cherry‐oat aphid Rhopalosiphum padi (L.) (Hemiptera: Aphididae) is a key pest of wheat in China. Chitosan oligosaccharide (COS) has been widely used due to its biocompatibility, antibacterial activity, environmental friendliness and convenient extraction. This study was aimed at determining the acute toxicity of COS on R. padi and transgenerational effects of sublethal concentrations of COS on the biological characteristics of R. padi. The results indicated that COS possessed acute toxicity against R. padi after 48 h of exposure (LC50: 1227.35 mg/L). The sublethal concentration of COS (LC15: 260 mg/L) induced a decrease in adult longevity, adult prereproductive period and fecundity in the first filial generation (F1). Moreover, in F1 progeny, nymphal (1st–3rd), preadult and total prereproductive period significantly enhanced due to sublethal dose. Moreover, finite rate of increase (λ), the intrinsic rate of increase (r) and net reproductive rate (R0) of F1 progeny were significantly decreased, whereas a sublethal COS concentration exposure significantly increased the mean generation time (T) of F1 progeny. Overall, the study shows that sublethal concentration of COS can significantly suppress population growth of R. padi F1 generation, showing the potential of COS as a biorational option to manage aphids. [ABSTRACT FROM AUTHOR]

Informed and effective management of emerging infectious diseases can be improved by a clear understanding of host–pathogen–environment interactions. Impacts of the seasonal environment on pathogen dynamics and host responses are poorly described in most reptile host–fungal pathogen systems. Here, we describe seasonal patterns of ophidiomycosis, a disease caused by the fungus Ophidiomyces ophidiicola (Oo), in a population of pygmy rattlesnakes, Sistrurus miliarius, in central Florida. We used field observations of gross clinical signs of disease in combination with qPCR on skin swabs to examine the seasonal prevalence of Oo and patterns of clinical presentation in hosts. We monitored thermoregulatory behaviors, ecdysis, and reproductive status in free‐living snakes to examine seasonal associations between infection and host coping responses. Both the prevalence of Oo and clinical signs of disease varied strongly with the season (winter high and summer low). In both seasons, the presence of clinical signs was a strong predictor of the presence of Oo as identified by qPCR on skin swabs (78% probability across seasons). Snakes with clinical signs of disease were more likely to be observed exhibiting thermoregulatory behavior or in ecdysis compared to non‐clinical snakes across seasons. The prevalence of Oo was not significantly different in pregnant snakes compared to other reproductive categories, but pregnant females were less likely to exhibit clinical signs of disease compared to males. Our results highlight strong seasonal patterns in both host clinical signs and Oo prevalence and support the efficacy of using gross clinical signs of disease in combination with qPCR on skin swabs to assess disease dynamics in free‐living snakes. We also identify ecdysis and thermoregulatory behaviors as components of the seasonal disease‐coping response and highlight the need to examine these behaviors as potential drivers of seasonal infection outcomes in reptiles afflicted with fungal pathogens. [ABSTRACT FROM AUTHOR]

Exposure to sublethal doses of insecticide may affect biological traits in triatomines. We investigated the effects of toxicological phenotype (pyrethroid resistance status) and exposure to sublethal doses of deltamethrin on two traits of Triatoma infestans Klug (Heteroptera: Reduviidae) using a phenotypic plasticity experimental design. First‐instar nymphs from 14 and 10 full‐sib families from pyrethroid‐susceptible and pyrethroid‐resistant populations, respectively, were used. For the susceptible population, we treated first instars topically with acetone (control) or deltamethrin (treatment) once. For the resistant population, instars were treated once, twice and three times as first, third or fifth‐instar nymphs, respectively. We measured cuticle thickness, wing size and wing shape of 484 emerging adults, and tested for treatment effects using mixed ANOVA and MANOVA models. Toxicological phenotype, exposure to deltamethrin and full‐sib family exerted significant effects on cuticle thickness, wing size and wing shape. Adult triatomines previously treated with deltamethrin developed significantly thicker cuticles than control triatomines only in the resistant population and significantly bigger wings in both populations. Mean cuticle thickness and wing size increased with increasing exposures to deltamethrin. Exposure to sublethal doses of deltamethrin generated morphological modifications that may affect insect survival and flight dispersal, and hence may have evolutionary and epidemiological consequences. [ABSTRACT FROM AUTHOR]

Both the American lobster fishery and salmon aquaculture are important to the economy of Atlantic Canada. Where these industries operate in proximity, research is needed to better understand any interactions and their possible effects. This study explored the effects of azamethiphos on survival and development of larval American lobsters, Homarus americanus, using exposures that reflect concentrations and durations of azamethiphos (anti‐sea lice therapeutant used in salmon aquaculture) that can be found in the environment following treatment. In adult trials, we recorded the survival and behaviour of individuals consecutively exposed to short pulses of low concentrations of azamethiphos for a period of 1 to 4 days. Larvae from all stages (I‐IV) exhibited an immobilization response when exposed to azamethiphos and that the concentration of azamethiphos that results in a 50% increase in immobilization decreases at increasing exposure time and was as low as 2.9 μgL−1 for a 3 h exposure. After exposure, we registered mortality occurring within 5 days and during the moulting window. In the larval trials the concentration required to reduce the acetylcholinesterase (AChE) activity by 50% increased from stages I to III. In the trials conducted with adults, we observed no mortality over 21 days, but did record an increase in aggressive behaviour with an increasing number of exposures. The temporal overlap between the release of larval lobster stages and the use of azamethiphos is important to consider when assessing potential risk. [ABSTRACT FROM AUTHOR]

Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Triazoles are suspected to have an impact on nontarget species due to their interactions with nonfungal sterol synthesis, and wild birds are likely to be contaminated by triazole fungicides because many of them live in agroecosystems. We experimentally tested whether exposure to environmental concentrations of a triazole could alter key integrative traits (metabolic rates and body condition) of an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild‐caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for 7 continuous months to tebuconazole through drinking water. The metabolic rates of exposed and control sparrows were then measured at two different temperatures (12 °C and 25 °C), which correspond, respectively, to the thermoregulation and thermoneutrality temperatures of this species. We found that exposed sparrows had lower resting metabolic rates (i.e., measured at thermoneutrality, 25 °C) than controls. However, the thermoregulatory metabolic rates (i.e., measured at 12 °C) did not differ between exposed and control sparrows. Although the body mass and condition were not measured at the beginning of the exposure, sparrows at the time of the metabolic measurements 7 months after the onset of such exposure had a higher body condition than controls, supporting further the idea that tebuconazole affects metabolic functions. Our study demonstrates for the first time that the use of tebuconazole can alter metabolism and could potentially lead to adverse effects in birds. Environ Toxicol Chem 2022;41:2500–2511. © 2022 SETAC [ABSTRACT FROM AUTHOR]

BACKGROUND: Pesticides can be noxious to non‐target beneficial arthropods and their negative effects have been recently recognized even at low doses. The predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) plays an important role in controlling insect pests in solanaceous crops, but its concurrent herbivory often poses relevant concerns for tomato production. Although insecticide side effects on N. tenuis have been previously studied, little is known on the potential implications of neurotoxic chemicals at low concentrations. We assessed the baseline toxicity of three neurotoxic insecticides (lambda‐cyhalothrin, spinosad and chlorpyrifos) on N. tenuis by topical contact exposure. The behavioral and reproduction capacity of the predator was then investigated upon exposure to three estimated low‐lethal concentrations (LC1, LC10 and LC30). RESULTS: Predator survival varied among insecticides and concentrations, with LC30/label rate ratios ranging from 8.45% to 65.40% for spinosad and lambda‐cyhalothrin, respectively. All insecticides reduced the fertility of N. tenuis females at all estimated low‐lethal concentrations. Chlorpyrifos seriously compromised predator orientation towards a host plant even at LC1, while the same effect was observed for lambda‐cyhalothrin and spinosad solely at LC30. Lambda‐cyhalothrin (at all concentrations) and chlorpyrifos (at LC10 and LC30) also affected the time taken by N. tenuis females to make a choice. CONCLUSION: The results indicate that all three insecticides can be detrimental to N. tenuis and should be avoided when presence of the predator is desirable. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The foraging and nesting performance of bees can provide important information on bee health and is of interest for risk and impact assessment of environmental stressors. While radiofrequency identification (RFID) technology is an efficient tool increasingly used for the collection of behavioral data in social bee species such as honeybees, behavioral studies on solitary bees still largely depend on direct observations, which is very time‐consuming. Here, we present a novel automated methodological approach of individually and simultaneously tracking and analyzing foraging and nesting behavior of numerous cavity‐nesting solitary bees. The approach consists of monitoring nesting units by video recording and automated analysis of videos by machine learning‐based software. This Bee Tracker software consists of four trained deep learning networks to detect bees that enter or leave their nest and to recognize individual IDs on the bees' thorax and the IDs of their nests according to their positions in the nesting unit. The software is able to identify each nest of each individual nesting bee, which permits to measure individual‐based measures of reproductive success. Moreover, the software quantifies the number of cavities a female enters until it finds its nest as a proxy of nest recognition, and it provides information on the number and duration of foraging trips. By training the software on 8 videos recording 24 nesting females per video, the software achieved a precision of 96% correct measurements of these parameters. The software could be adapted to various experimental setups by training it according to a set of videos. The presented method allows to efficiently collect large amounts of data on cavity‐nesting solitary bee species and represents a promising new tool for the monitoring and assessment of behavior and reproductive success under laboratory, semi‐field, and field conditions. [ABSTRACT FROM AUTHOR]

Understanding pesticide non‐target effects on natural enemies is a key element of successful conservation biological control. Due to their importance in agroecosystems worldwide, the phytoseiid mites are the most well‐studied natural enemies in pesticide selectivity research. The wealth of literature associated with this topic allows for a thorough meta‐analysis of pesticide non‐target effects and may also indicate general trends relevant to many cropping systems. We conducted a meta‐analysis using 2386 observations from 154 published papers examining the impact of pesticides on lethal (adult and juvenile mortality) and sublethal (fecundity, egg hatch) effects. Insecticides and herbicides did not statistically differ in toxicity to phytoseiids, but research on herbicide non‐target effects is scarce. Specific insecticides, fungicides, and miticides were sorted into least and most harmful categories. Phytoseiid species also differed in sensitivity, with Galendromus occidentalis (Nesbitt), Neoseiulus californicus (McGregor), and Typhlodromus pyri Scheuten among the least sensitive species. Sensitivity variation may be partly due to pesticide resistance; the greatest differences between species were within older mode of action (MOA) groups, where resistance development has been documented. It has been speculated that specialist phytoseiids, which closely associate with Tetranychus spp. spider mites, have more opportunities for resistance development due to their necessary proximity to a pest that rapidly develops resistance. Effect sizes were higher for generalist phytoseiid species, supporting this hypothesis. This meta‐analysis highlights pesticide types (herbicides) and MOA groups where more research is clearly needed. Our analysis also allows for more robust generalizations regarding which pesticides are harmful or selective to phytoseiids. © 2021 Society of Chemical Industry. This article has been contributed to by US Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Bumblebees can be exposed to neonicotinoid pesticides through nectar and pollen collected from treated crops, which can cause lethal and sublethal effects in these nontarget pollinators. However, the body distribution of the compound after exposure to neonicotinoids in bumblebees is not well studied. Bumblebee colonies (Bombus terrestris, n = 20) were exposed to field‐realistic concentrations of clothianidin through artificial nectar (3.6–13 µg/L) for 9 d. Comparison of the nominal with the measured exposure in nectar indicated good compliance, confirming the applicability of the method. When quantified, clothianidin showed a concentration‐dependent occurrence in the head and body of workers (head: <0.2–2.17 µg/kg; body: <0.2–3.17 µg/kg), and in the body of queens (<0.2–2.49 µg/kg), although concentrations were below those measured in the nectar (bioaccumulation factor = 0.2). Exposure to clothianidin did not affect mortality nor brood production, nor did it have a statistically significant effect on nectar consumption and size of food storage. However, visual inspection suggests higher nectar consumption of nectar with low clothianidin content compared with nectar with no or high clothianidin content. Our results show that dietary clothianidin is taken up in bumblebees, but does not bioaccumulate to elevated levels compared with exposure. Still, clothianidin may elicit responses that affect feeding behavior of the pollinator B. terrestris, although our endpoints were not significantly affected. Environ Toxicol Chem 2021;40:2781–2790. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Anthropogenic noise is a pervasive and increasing source of disturbance to wildlife. Marine mammals exhibit behavioural and physiological responses to naval sonar and other sound sources. The lost foraging opportunities and elevated locomotor effort associated with sonar disturbance likely carry energetic costs, which may lead to population‐level consequences.We modelled the energetic costs associated with behavioural responses using (a) empirical datasets of cetacean feeding rates and prey characteristics and (b) allometry of swimming performance and metabolic rates.We applied our model to compare the short‐term (i.e. the scale of the disturbance response; hours to days) energetic costs of a variety of observed behavioural responses. Efficient foragers (e.g. baleen whales) incur a greater relative energetic cost for mild behavioural responses as compared to the most extreme observed response for larger odontocetes (e.g. beaked whales). Energetic costs are more sensitive to lost feeding opportunities than increased energy expenditure from elevated locomotor effort.To scale up from short‐term costs to long‐term effects (months to years), future research should address individuals' capacity to compensate for energetic losses as well as energetic thresholds for demographic rates (survival, fecundity). We discuss how relative energetic costs correlate with species' pace of life and the implications for conservation planning.Synthesis and applications. Current approaches towards understanding the Population Consequences of Disturbance (PCoD) often must rely on expert opinion due to data deficiency. Our model provides an empirical method for linking behaviour to energetics, which is critical for managers to make informed decisions on actions that may affect marine mammal species. Furthermore, our model is applicable to other forms of disturbance, such as vessel traffic or seismic exploration, and our scaling approach enables risk projections for understudied species. ​ [ABSTRACT FROM AUTHOR]

Passive integrated transponder (PIT) tags allow a range of individual-level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black-capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio-frequency identification (RFID) redetections of leg band PIT tags to evaluate sex-specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine. [ABSTRACT FROM AUTHOR]

Passive integrated transponder (PIT) tags allow a range of individual-level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black-capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio-frequency identification (RFID) redetections of leg band PIT tags to evaluate sex-specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine. [ABSTRACT FROM AUTHOR]

Imidacloprid, a neonicotinoid pesticide, is used to prevent the spread of the hemlock woolly adelgid, currently affecting Eastern Hemlock trees across North America. When the pesticide is sprayed directly onto soil around infested trees (soil drenching), it can run off into aquatic systems, with potential negative effects on biota. Simultaneously, climate change may lead to faster pool drying, which acts as an additional stressor for sensitive species such as amphibians. We evaluated the sublethal effects of imidacloprid (10 ppb), and interaction with shorter hydroperiods on the larval behavior, growth, and survival of a model organism, the wood frog (Rana sylvatica). We performed 3 behavioral experiments evaluating swimming speed, time spent swimming, and distance the larvae swam. We found that larvae raised in 10 ppb imidacloprid or shorter hydroperiod did not differ in their swimming time, distance, and speed from nonexposed larvae. Naïve larvae exposed for 20 min to 10‐ to 500‐ppb concentrations also showed similar performance to nonexposed larvae. However, when we applied a stimulus halfway through each experiment, we found that larvae exposed to 10 ppb imidacloprid (short and long term) swam shorter distances and spent less time swimming, suggesting that imidacloprid exposure may slow reaction time, potentially increasing the risk of predation. To minimize impacts on pool‐breeding amphibians, imidacloprid application to combat the invasive hemlock woolly adelgid should use trunk injection and avoid soil drenching. Environ Toxicol Chem 2021;40:1840–1849. © 2021 SETAC [ABSTRACT FROM AUTHOR]

BACKGROUND: Aphis gossypii, a polyphagous and recurrent pest induced by pesticides, causes tremendous loss crop yields each year. Previous studies on the mechanism of pesticide‐induced sublethal effects mainly focus on the gene level. The symbiotic bacteria are also important participants of this mechanism, but their roles in hormesis are still unclear. RESULTS: In this study, life table parameters and 16S rRNA sequencing were applied to evaluate the sublethal and transgenerational effects of sulfoxaflor on adult A. gossypii after 24‐h LC20 (6.96 mg L−1) concentration exposure. The results indicated that the LC20 of sulfoxaflor significantly reduced the finite rate of increase (λ) and net reproductive rate (R0) of parent generation (G0), and significantly increased mean generation time (T) of G1 and G2, but not of G3 and G4. Both reproductive period and fecundity of G1 and G2 were significantly higher than those of the control. Furthermore, our sequencing data revealed that more than 95% bacterial communities were dominated by the phylum Proteobacteria, in which the maximum proportion genus was the primary symbiont Buchnera and the facultative symbiont Arsenophonus. Compared to those of the control, the abundance and composition of symbiotic bacteria of A. gossypii for three successive generations (G0–G2) were changed after G0 A. gossypii was exposed to sulfoxaflor: the diversity of the bacterial community was decreased, but the abundance of Buchnera was increased (G0), while the abundance of Arsenophonus was decreased. Contrary to G0, G1 and G2 cotton aphid exhibited an increased relative abundance of Arsenophonus in the sublethal treatment group. CONCLUSION: Taken together, our results provide an insight into the interactions among pesticide resistance, aphids, and symbionts, which will eventually help to better manage the resurgence of A. gossypii. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Helicoverpa zea is managed with foliar applications of chlorantraniliprole in cotton varieties that do not express the Vip3Aa19 toxin in the US Cotton Belt. Foliar insecticides and Bt could interact to influence larval susceptibility. Therefore, it has been suggested that chlorantraniliprole can be used as a tool for Bt resistance management. We designed field and laboratory studies to test the hypothesis that the interaction of Bt toxin and chlorantraniliprole application would result in lower H. zea larval survival when compared to the individual effect of Bt or chlorantraniliprole alone. We also tested for these interactions over time, since chlorantraniliprole residual has not been studied in cotton. RESULTS: Results from two field experiments and two laboratory experiments were similar. We found no interactions with Bt and chlorantraniliprole using data not corrected for natural mortality in untreated plots, indicating that these factors did not interact to influence survival. Moreover, we found that Bt and chlorantraniliprole did not interact to influence larval weight and instar. Chlorantraniliprole had lethal and sublethal effects on H. zea larval growth parameters feeding on cotton leaves up to 22 days after application, the final time period that we tested. Finally, concentration of chlorantraniliprole in the leaf was associated with larval survival for the duration of this study, but not larval growth or instar. CONCLUSION: Our findings complement the recommendation to use chlorantraniliprole for managing H. zea in cotton, given its long‐residual effects. However, the utility of chlorantraniliprole as a Bt‐resistance management tool for H. zea remains unclear. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Lufenuron, a molecule that belongs to the chitin synthesis inhibitors group of insect growth regulators, has a still unclear mode of action, but probably it affects chitin synthesis at a post‐transcriptional level. In this work, we report the effects of lufenuron on nutrition and reproduction in adult females of Anthonomus grandis, the main neotropical cotton pest and tried to link the effects on peritrophic matrix (PM) with egg viability. After Lufenuron treatment A. grandis females presented weight loss and less accumulation of protein and lipids probably due to PM breakdown. Also, treated females produce the same quantity of eggs as the control, although eggs from lufenuron‐treated females were less viable. After morphological and histochemical analysis, we have noticed that oocytes from lufenuron‐treated females contained less protein. Finally, lufenuron‐treated females produced at least nine times less vitellogenin (AgraVg) RNA than control females. We specifically showed that lufenuron treatment caused PM disruption and it has probably led to vitellogenin (AgraVg) downregulation in females culminating in egg unviability. The effect of lufenuron on PM leads to insect malnutrition, and this malnutrition downregulates vitellogenin among other genes. This is the first work that describes and tries to correlate the lufenuron effects on adult females. [ABSTRACT FROM AUTHOR]

BACKGROUND: Phosphine‐susceptible or resistant populations of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults were exposed to 0 (control), 1000 and 3000 ppm of phosphine for 15 or 90 min, to estimate behavioral and mobility responses after exposure to phosphine. Knockdown of the exposed individuals after exposure was recorded visually. The total distance moved and velocity of movement were assessed immediately after exposure to phosphine, 2 or 24 h later using a camera coupled with automated video tracking software (i.e. Ethovision®). RESULTS: For both species tested, the highest percentage of dead adults was noted at the highest concentration (3000 ppm) for both exposure times. For T. castaneum, total distance moved and velocity decreased as the concentration increased for the susceptible population, whereas there was significant variation among individuals in the resistant population. For R. dominica, the distance moved was reduced at the highest concentrations. Individuals of R. dominica moved less than those of T. castaneum and there were significant differences in mobility between susceptible and resistant populations for both species tested. Recovery was much faster in the case of the resistant populations. CONCLUSIONS: Changes in movement parameters can be further exploited in assessing the efficacy of different management tactics, such as trapping and sampling. Automated video tracking systems such as Ethovision® can be used to track and record insect behavioral response, providing a more objective measure of insecticide efficacy than visual categorizations. These data shed light on insect mobility and behavioral responses to fumigation treatments in relation to resistance. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Prevention is the first line of defense in mitigating losses of post‐harvest crops. Long‐lasting insecticide treated (LLIN) could be used in food facilities to expose insects to insecticide at different areas within a facility. Prior research has shown that single short exposures reduce movement and longer exposures increase mortality for stored‐product insect pests, but we do not know how multiple short duration exposures and biotic and abiotic conditions affect insects exposed to LLIN. Here, we repeatedly exposed red flour beetles, Tribolium castaneum, to LLIN to assess the cumulative effects. We also examined the effects of beetle age and time of day during exposure, and temperature, humidity and food availability during recovery after a single exposure to LLIN. RESULTS: We found that four repeated 10‐min exposures had similar knockdown effects as a single 30‐min exposure. We also found that beetles were more affected when aged 1–6 days versus 14–20 days or were exposed at mid‐ or late in the day versus earlier in the day. Higher recovery levels were observed with food and at higher relative humidity. In addition, older beetles were more active than younger beetles during exposure, which could reduce time in contact with netting and partially explain why older beetles tended to be less affected. CONCLUSION: Some individuals can recover after exposure to LLIN, dependent on exposure duration and environmental factors, but our study shows that sublethal effects likely persist and future work should consider the physiology of T. castaneum before, during, and after exposure to LLIN. Published 2020. This article is a U.S. Government work and is in the public domain in the USA [ABSTRACT FROM AUTHOR]

Life‐history traits determine individual fitness and the fate of populations. Imidacloprid, a widely used neonicotinoid insecticide, which persists in soil for more than 100 d at biologically relevant levels, may affect nontarget and ecologically important species, such as collembolans. In the present study, we determined the sublethal effects of short‐term imidacloprid exposure and postexposure recovery in the collembolan Folsomia quadrioculata, which occurs abundantly across the northern hemisphere. We assessed survival, egg production, and hatching success in adult springtails exposed for 14 d through the diet to imidacloprid, followed by a 28‐d postexposure phase. Survival and hatching success were high throughout the experiment in all the treatments, with no clear concentration dependence. However, egg production declined during the exposure phase and nearly stopped between 8 and 14 d in all the treatments (except the control) but resumed during the postexposure phase. Moreover, the resumption of egg production showed a concentration‐dependent delay. Our findings suggest that low imidacloprid exposures can restrict reproduction, with potentially severe consequences for the population, notwithstanding the partial recovery in egg production. Environ Toxicol Chem 2021;40:139–147. © 2020 SETAC [ABSTRACT FROM AUTHOR]

BACKGROUND White and colored fiber cotton cultivars have been developed to increase production and opportunities for family farming. The broad mite, Polyphagotarsonemus latus (Banks) is an important pest in cotton crops, nevertheless, different cotton cultivars may influence its host selection and population growth. For P. latus control, acaricides application is commonly performed, although less is known about the sublethal effects of these products. Thus, the host preference and instantaneous rate of increase (ri) of P. latus were evaluated on white and colored cotton cultivars, as well as the lethal and sublethal effects of acaricides through mortality tests and population growth. RESULTS: In free‐choice tests to evaluate host preference among white and colored cotton cultivars, no preference was observed for P. latus. The instantaneous ri values were positive for all tested cultivars, however, differences were observed between the colored BRS Rubi and the white BRS 201. The population growth of P. latus decreased with increasing concentrations of the acaricides abamectin, spirodiclofen, azadirachtin and spiromesifen. Nevertheless, azadirachtin and spiromesifen presented positive ri values even at the highest lethal concentrations (LC90), while abamectin and spirodiclofen provided negative ri values of P. latus from LC90 and LC70, respectively. CONCLUSION: No host preference of P. latus was observed among white and colored cotton cultivar. Abamectin and spirodiclofen presented relevant sublethal effects that should be considered for the integrated management of this pest. [ABSTRACT FROM AUTHOR]

The very presence of predators can strongly influence flexible prey traits such as behavior, morphology, life history, and physiology. In a rapidly growing body of literature representing diverse ecological systems, these trait (or "fear") responses have been shown to influence prey fitness components and density, and to have indirect effects on other species. However, this broad and exciting literature is burdened with inconsistent terminology that is likely hindering the development of inclusive frameworks and general advances in ecology. We examine the diverse terminology used in the literature, and discuss pros and cons of the many terms used. Common problems include the same term being used for different processes, and many different terms being used for the same process. To mitigate terminological barriers, we developed a conceptual framework that explicitly distinguishes the multiple predation‐risk effects studied. These multiple effects, along with suggested standardized terminology, are risk‐induced trait responses (i.e., effects on prey traits), interaction modifications (i.e., effects on prey–other‐species interactions), nonconsumptive effects (i.e., effects on the fitness and density of the prey), and trait‐mediated indirect effects (i.e., the effects on the fitness and density of other species). We apply the framework to three well studied systems to highlight how it can illuminate commonalities and differences among study systems. By clarifying and elucidating conceptually similar processes, the framework and standardized terminology can facilitate communication of insights and methodologies across systems and foster cross‐disciplinary perspectives. [ABSTRACT FROM AUTHOR]

Neonicotinoid pesticides harm nontarget insects, but their sublethal effects on butterflies are understudied. We exposed larvae of 3 butterfly species (Pieris rapae, Colias philodice, and Danaus plexippus) to low levels of the neonicotinoid imidacloprid in their host plants and followed individuals to adulthood. Imidacloprid altered adult body size, especially in female monarchs, but its effects varied across maternal families, highlighting the importance of considering genetic variation in ecotoxicological testing. Environ Toxicol Chem 2020;39:2228–2236. © 2020 SETAC [ABSTRACT FROM AUTHOR]

BACKGROUND Encarsia formosa Gahan is the most important parasitoid exploited for the control of whitefly pests of vegetable crops. However, the non‐target effects of recently developed insecticides for controlling whiteflies toward this biocontrol agent is little documented. Here we evaluated the susceptibility of E. formosa adults and juveniles to eight commonly used insecticides against whiteflies. RESULTS: Residual toxicity tests on glass showed that E. formosa adults were susceptible (over 98% mortality after 6 h treated) to field concentrations of the tested neonicotinoids (imidacloprid, acetamiprid, nitenpyram and thiamethoxam), abamectin, cyantraniliprole, and sulfoxaflor at their field concentrations. Pyriproxyfen was harmless to both adult and pupae of E. formosa. A risk quotient analysis showed that toxicity of pyriproxyfen to E. formosa adults was the lowest, followed by acetamiprid and cyantraniliprole. In the leaf residues test, mortality of E. formosa adults under all insecticides decreased when the residue age increased. Interestingly, E. formosa experiencing contact with the residues of most insecticides, except pyriproxyfen and abamectin, parasitized significantly more hosts 5‐days after treatment, suggesting a hormetic effect on parasitism. CONCLUSION: The risk assessment of insecticides indicated that pyriproxyfen and cyantraniliprole were the least toxic to E. formosa. Our results suggest that the inclusion of the insecticides in sustainable integrated pest management programs of whiteflies should be carefully evaluated on a case‐by‐case basis. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Emergent diseases may result in population declines by inducing mortality directly or through sublethal effects on host reproduction. Snake fungal disease (SFD) is an emerging threat to biodiversity, but the sublethal impacts of disease on host fitness are poorly characterized. The cryptic nature of most snakes makes direct assessment of the fitness consequences of SFD challenging. In such contexts, measurement of sex steroids that correlate positively with seasonal reproductive investment may be useful in inferring the scope of disease impacts. To test the hypothesis that SFD is associated with reproductive suppression, we measured testosterone and estradiol in free‐ranging pygmy rattlesnakes with varying clinical signs of SFD. We also used real‐time PCR to validate the relationship between clinical signs and Ophidiomyces ophiodiicola (Oo) DNA presence on the skin. Infected males had lower testosterone compared to uninfected males during summer spermatogenesis and the fall breeding season. Infected females were less likely to have elevated estradiol compared to uninfected females during spring vitellogenesis. Approximately 85% of individuals with clinical signs were positive for Oo DNA. Our findings are consistent with the hypothesis that coping with SFD comes at a cost to the reproductive success of afflicted individuals, and that seasonal sex steroids may be valuable early indicators of sublethal effects. Snake fungal disease (SFD) is associated with suppression of sex steroid hormones in Pygmy rattlesnakes, Sisturus miliarius. Steroid suppression in infected males and females was only evident during seasonal reproductive events. SFD infection likely has associated sublethal reproductive costs in male and female rattlesnakes. [ABSTRACT FROM AUTHOR]

Floral resources and natural enemies are considered important drivers of wild bee population dynamics, yet there is little information on how these factors, either independently or in combination, influence the demographic performance of bees. Bumble bees (Bombus spp.), ecologically important social insects, have long colony cycles lasting many weeks. Food shortfalls during the colony lifetime can result in smaller colony sizes and lower reproductive output. Conopid flies (Conopidae, Diptera) are prevalent endoparasitoids of bumble bees, often infecting high percentages of free‐flying individuals. Conopids can reduce worker life span and foraging efficiency; consequently, they may negatively affect colony success. In this study, we evaluated how seasonal variability in food resources and conopid parasitism together influence the productivity of bumble bee colonies through construction of a simulation model. In addition to simulating colony performance in relation to a defined food environment and conopid‐induced worker mortality, we evaluated how daily background mortality risk and the timing of colony initiation affected growth and reproductive outcomes of colonies, as well as the degree of influence exerted by conopids. Model parameters were largely informed by field data collected from Bombus impatiens colonies at our study site (Blandy Experimental Farm, Boyce, Virginia, USA), including data on forager risk of conopid parasitism as assessed using radio‐frequency identification (RFID) technology. In spite of the high probability of parasitism (4% per hour of flight during seasonal peak) incorporated into our model simulations, lethal parasitism by conopids generally had a modest influence on colony productivity, reducing reproductive output by 15% or less across most tested scenarios. However, conopids were more influential under very low resource conditions, reducing reproductive output by 21–28%. Inclusion of sublethal effects of conopids on foraging activity further reduced colony performance in all scenarios, but had a greater impact on colony performance under the poorest resource conditions. This work emphasizes that the importance of natural enemies to the demographic performance of bees can increase under certain environmental conditions and highlights the value of using models to consider multiple stressors that are difficult to evaluate simultaneously in field experiments. [ABSTRACT FROM AUTHOR]

BACKGROUND: The efficacy of pre-emergence herbicides within fields is spatially variable as a consequence of soil heterogeneity. We quantified the effect of soil organic matter on the efficacy of two pre-emergence herbicides, flufenacet and pendimethalin, against Alopecurusmyosuroides and investigated the implications of variation in organic matter for weed management using a crop-weed competition model. RESULTS: Soil organic matter played a critical role in determining the level of control achieved. The high organicmatter soil had more surviving weeds with higher biomass than the low organic matter soil. In the absence of competition, surviving plants recovered to produce the same amount of seed as if no herbicide had been applied. The competition model predicted that weeds surviving pre-emergence herbicides could compensate for sublethal effects even when competing with the crop. The ED50 (median effective dose) was higher for weed seed production than seedling mortality or biomass. This difference was greatest on high organic matter soil. CONCLUSION: These results showthat the application rate of herbicides should be adjusted to account for within-field variation in soil organic matter. The results from the modelling emphasised the importance of crop competition in limiting the capacity of weeds surviving pre-emergence herbicides to compensate and replenish the seedbank. [ABSTRACT FROM AUTHOR]

BACKGROUND: The rice leaffolder, Cnaphalocrocis medinalis, is an important rice pest. The sublethal effects of chlorpyrifos, chlorantraniliprole, emamectin benzoate and spinosad were investigated on the folding and spinning behaviors of third- to fifth-instar C. medinalis larvae (L3-L5) after insecticidal exposure of the second instar. RESULTS: A 25% lethal concentration (LC25) of chlorpyrifos prolonged the leaf selection time of L5, and reduced the number of binds per primary fold for L4 and L5. An LC10 of chlorantraniliprole reduced the number of binds per primary fold for L4 and increased the number of head swings per bind for L5. An LC10 of emamectin benzoate shortened the primary fold length for L5 and decreased the number of head swings per primary fold for L3 and L4 and the number of head swings per bind for L3, while an LC25 of emamectin benzoate shortened the fold length per 24 h for L5 and folding time for L3. An LC10 of spinosad lowered the fold length per 24 h and the number of head swings for L5. An LC25 of spinosad prolonged leaf selection time, and decreased primary fold length, binds per primary fold, binds per fold and fold length per 24 h in L5. CONCLUSION: Emamectin benzoate and spinosad exerted stronger sublethal effects on the folding and spinning behavior of C. medinalis than chlorpyrifos and chlorantraniliprole. These results provide better understanding of the sublethal effects of interactions of insecticides on C. medinalis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mole crickets (Neoscapteriscus spp.) consume turfgrasses and pasture grasses and uproot plants by their tunneling, which is detrimental to turf aesthetics and decreases forage quantity and quality. Insecticides are frequently used to prevent damage. In typical field trials, damage symptoms, not percent mortality or achieved level of control, are used to assess treatment efficacy. Here, however, laboratory tests assessed the direct effect of key insecticides on Neoscapteriscus mole cricket behavior. RESULTS: Mole crickets, Neoscapteriscus spp., were able to detect and avoid areas treated with fipronil [formulated product (FP)] and imidacloprid (FP). They tunneled less in sand treated with fipronil and avoided sand treated with fipronil and imidacloprid if given a choice. Mole crickets escaped areas treated with acephate, bifenthrin and fipronil. Bifenthrin and acephate caused increased tunneling during the first 90 min of observation. Fipronil and imidacloprid significantly reduced overall tunneling on treated areas. CONCLUSION: Tested insecticides elicited two types of behavioral changes in Neoscapteriscus mole crickets: increased locomotory activity and tunneling [acephate (organophosphate) and bifenthrin (pyrethroid)] and reduced spatial movement [fipronil (phenylpyrazole) and imidacloprid (neonicotinoid)]. These behavioral responses resulted mainly from contact chemoreception and inherent neurotoxicity of the chemicals on Neoscapteriscus mole crickets. [ABSTRACT FROM AUTHOR]

BACKGROUND Juvenile hormone ( JH) regulates the development and reproduction of insects. The sublethal effects of chlorantraniliprole on JH levels and mRNA expression of JH acid methyltransferase gene ( CsJHAMT) and farnesyl diphosphate synthase genes ( CsFPPS1 and CsFPPS2) in Chilo suppressalis (Walker) were investigated. RESULTS Exposure of sublethal concentrations of chlorantraniliprole ( LC10 and LC30) to the third instar larvae of C. suppressalis significantly increased the JH levels in all developmental stages investigated including larvae 72 h after treatment, the first, third and fifth day of female pupae, as well as newly emerged, 12-h-old and 24-h-old female adults. A general trend of increased mRNA expression levels of CsJHAMT, CsFPPS1and CsFPPS2 was also observed in LC10 and LC30 treatment groups. Notably, the mRNA expression level of CsJHAMT significantly increased by 7.46-fold in the larvae 72 h after LC30 treatment. A significant increase of the mRNA expression levels of CsFPPS2 was also observed in the fifth day female pupae of LC10 and LC30 treatment groups (2.60-fold and 2.62-fold, respectively) as well as in 12-h-old female adults of the LC30 treatment group (3.45-fold). CONCLUSION Sublethal concentrations of chlorantraniliprole might upregulate the expression of JH biosynthesis genes and in turn result in an increase of JH level in C. suppressalis. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The interest in and utilization of botanical insecticides, particularly essential oils, has become increasingly relevant to the control of insect pests. However, the potential ecotoxicological risks or flaws (including sublethal effects on the targeted pest generation and its subsequent progeny) of this pest control tool have been neglected frequently. Here, we evaluated the effects of sublethal exposure to clove, Syzygium aromaticum (L.) Merrill & Perry ( Myrtaceae), and cinnamon, Cinnamomum verum J. Presl ( Lauraceae), essential oils on adult (F0) maize weevils, Sitophilus zeamais Motschulsky ( Coleoptera: Curculionidae), and the physiology (e.g., body mass, respirometry, and grain consumption) and population dynamics (e.g., daily emergence and sex ratio) of their progeny. Longevities of the parents were negatively affected by the essential oils in a concentration-dependent manner. Parental sublethal exposure to clove oil (0.17 μl cm−2) accelerated offspring emergence but delayed the emergence of females compared to males. Parents that were sublethally exposed to clove (0.17 μl cm−2) or cinnamon (0.35 μl cm−2) essential oils produced heavier offspring. Parental sublethal exposure to cinnamon essential oil accelerated offspring emergence (at 0.70 μl cm−2), delayed female emergence (at 0.17 μl cm−2), and enhanced grain consumption (at 0.35 and 0.70 μl cm−2) of the progeny. Thus, our findings indicate that sublethal exposure to clove and cinnamon essential oils is capable of promoting transgenerational effects in S. zeamais that can negatively impact the control efficacy of such products. [ABSTRACT FROM AUTHOR]

Backswimmers (Hemiptera: Heteroptera: Notonectidae) are insect predators in a wide variety of freshwater habitats. These insects are well known through their role as mosquito biocontrol agents, their ability to prey on immature fishes and frogs, and because they are often the first to colonize aquatic habitats. As a consequence, these predators may face intended or unintended insecticide exposures that may lead to death or to impairment of essential behaviors (e.g., swimming and position in the water column). The toxicity of deltamethrin (a type II pyrethroid insecticide stressor) and the swimming activity of the backswimmers Buenoa tarsalis and Martarega bentoi were evaluated. Concentration-mortality and survival bioassays were conducted with the insecticide, which were compared with controls without deltamethrin. Deltamethrin was 26-fold more toxic to B. tarsalis (median lethal concentration [LC50] = 4.0 ng a.i./L) than to M. bentoi (LC50 = 102.5 ng a.i./L). The pattern of occupation of B. tarsalis, but not of M. bentoi, in the water column was also disrupted, and B. tarsalis was forced to stay near the water surface longer with exposure to deltamethrin. Thus, based on the findings, B. tarsalis was less resilient to deltamethrin exposure compared with M. bentoi, and the efficacy of swimming-dependent processes might be negatively affected (e.g., prey catching, partner encounter, and antipredator behaviors) for B. tarsalis under deltamethrin exposure. Environ Toxicol Chem 2017;36:1235-1242. © 2016 SETAC [ABSTRACT FROM AUTHOR]

The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000 mg Cl−/L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods ( Hyalella azteca) and the mortality of banded mystery snails ( Viviparus georgianus) and fingernail clams ( Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct and indirect effects. [ABSTRACT FROM AUTHOR]