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1.
Ecotoxicol Environ Saf ; 212: 111984, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33517036

RESUMO

As a natural enemy of green peach aphids, harlequin ladybirds, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), are also indirectly affected by azadirachtin. In this study, we evaluated the effects of ladybird exposure to azadirachtin through azadirachtin-treated aphids. About 2 mg/L azadirachtin treated aphid can deliver the azadirachtin to ladybird larvae in 12 and 24 h. And azadirachtin treatment affected the rate at which fourth instar larvae and adult ladybirds preyed on aphids. Furthermore, the antifeedant effect increased with increasing azadirachtin concentrations. Twelve hours after exposing fourth instar ladybird larvae to aphids treated with 10 mg/L azadirachtin, the antifeedant effect was 47.70%. Twelve hours after exposing adult ladybirds to aphids treated with 2 mg/L azadirachtin, the antifeedant effect was 67.49%. Forty-eight hours after exposing ladybird larvae to azadirachtin-treated aphids, their bodyweights were 8.37 ± 0.044 mg (2 mg/L azadirachtin), 3.70 ± 0.491 mg (10 mg/L azadirachtin), and 2.39 ± 0.129 mg (50 mg/L azadirachtin). Treatment with azadirachtin affected the ability of ladybirds to prey on aphids. The results indicated that the instant attack rate of ladybird larvae and adults and the daily maximum predation rate were reduced by azadirachtin treatment. Superoxide dismutase (SOD), peroxidase (POD), and peroxide (CAT) enzyme activities of ladybirds were affected after feeding on aphids treated with azadirachtin. Azadirachtin has certain antifeedant effects on ladybirds and affects the ability of ladybirds to prey on aphids and the activities of SOD, POD, and CAT enzymes, which results in inhibition of normal body development.


Assuntos
Afídeos/fisiologia , Besouros/enzimologia , Limoninas/toxicidade , Comportamento Predatório/efeitos dos fármacos , Animais , Besouros/efeitos dos fármacos , Besouros/crescimento & desenvolvimento , Besouros/fisiologia , Larva/crescimento & desenvolvimento , Ervilhas
2.
Chemosphere ; 262: 127785, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182149

RESUMO

Although glyphosate is widely used for weed pest control, it might have negative side effects on natural enemies. Wolf spiders are one of the most representative predators found on soybean crops in Uruguay, preying on a wide variety of potential pests. However, the sublethal effects that pesticides might have on this group have been poorly explored for South American species. Herein, we explored the sublethal effects of glyphosate on the functional response of the wolf spider Hogna cf. bivittata against three potential pest insects, namely ant (Acromyrmex sp.), caterpillar (Anticarsia gemmatalis), and cricket (Miogryllus sp.). We contaminated residually adult females of the species Hogna cf. bivittata with glyphosate (Roundup®) and compared their functional response against non-contaminated spiders. We did not observe any mortality during the study. We found that overall Hogna cf. bivittata showed a functional response type II against crickets and caterpillars but no functional response to ants. Contaminated spiders killed less ants and caterpillars in comparison to the control group, probably as a consequence of the irritating effects of glyphosate. We did not observe differences in functional response to crickets at the evaluated densities, probably as a consequence of the low capture rate against this prey. Although glyphosate does not specifically target spiders, it might have negative sublethal effects on native predators such as Hogna cf. bivittata. Further studies should explore effect of glyphosate on other native predators from South American crops.


Assuntos
Glicina/análogos & derivados , Praguicidas/toxicidade , Aranhas/efeitos dos fármacos , Animais , Formigas , Produtos Agrícolas , Feminino , Glicina/toxicidade , Gryllidae , Mariposas , Comportamento Predatório/efeitos dos fármacos , Uruguai
3.
Chemosphere ; 261: 127720, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32721693

RESUMO

Podisus nigrispinus Dallas (Heteroptera: Pentatomidae) preys on insect pests in eucalyptus plantations where it can be exposed to insecticides used in pest control. The effect of insecticides on non-target natural enemies requires further study. The objective of the present study was to evaluate the side-effects of Bacillus thuringiensis (Bt), permethrin, tebufenozide and thiamethoxam on third instar nymphs of the predator P. nigrispinus in the laboratory. The toxicity of insecticides for this insect was determined by estimating their lethal concentrations. Podisus nigrispinus behavior after exposure to insecticides was analyzed using a video tracking system and the respiratory rate with a respirometer. Prey/nymph consumption was assessed after 24 h of starvation. The preference of P. nigrispinus nymphs, for prey treated or not with the insecticides, was evaluated in free choice tests. The insecticides Bt [LC50 = 1.10(0.83-1.46) mg mL-1], permethrin [LC50 = 0.25(0.17-0.34) mg mL-1], tebufenozide [LC50 = 5.71(4.17-7.57) mg mL-1] and thiamethoxam [LC50 = 0.04(0.02-0.06) mg mL-1] are toxic to P. nigrispinus nymphs. Bt and the insecticides tebufenozide, permethrin and thiamethoxam reduced the respiratory rate of P. nigrispinus. The insecticides permethrin, tebufenozide and thiamethoxam affect the locomotion of this insect's nymphs. Prey treated with Bt, permethrin and thiamethoxam are less preferred by P. nigrispinus. The survival of the nymphs of this predator was 93.3%, 66.7%, 56.6%, 0% and 0% in the control, tebufenozide, Bt, permethrin and thiamethoxam treatments, respectively. In addition, the reduction of prey consumption, treated with neurotoxic insecticides, reduces the predatory potential of this natural enemy. Bt and tefubenozide present low toxicity for P. nigrispinus, but the neurotoxic products have low compatibility with this natural enemy and, therefore, are not recommended, with this predator in the management of forest insect pests.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Heterópteros/efeitos dos fármacos , Inseticidas/toxicidade , Ninfa/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Animais , Bacillus thuringiensis/efeitos dos fármacos , Bacillus thuringiensis/crescimento & desenvolvimento , Brasil , Eucalyptus/crescimento & desenvolvimento , Controle de Pragas , Controle Biológico de Vetores
4.
Aquat Toxicol ; 226: 105564, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32683169

RESUMO

Millions of pharmaceuticals are prescribed each year. Wastewater treatment plants fail to remove all pharmaceuticals from discharge leading to detectable concentrations entering aquatic ecosystems where the compounds can encounter nontarget organisms. Selective serotonin reuptake inhibitor (SSRI) class of antidepressants interact with transporters in the brain and peripheral nervous system to change serotonin levels in the synapse. Sublethal exposure to SSRIs can impact fish feeding behaviors, which can have impacts on ecological fitness. We exposed hybrid striped bass (Morone saxatilis x Morone chrysops) to low, medium, and high concentrations of sertraline (4.5 ± 0.84 µg/L, 35.4 ± 2.18 µg/L, and 96.8 ± 6.4 µg/L) over six days with six additional recovery days. Concentrations were chosen to compare results with a mixture study previously completed in our lab. Every three days we tracked how long each bass took to consume four fathead minnows (Pimephales promelas) and conducted destructive sampling to obtain brain and plasma samples. Brain and plasma samples were analyzed for sertraline levels and we calculated whole brain serotonin levels. During the exposure period, bass showed an increased time to capture prey, but time to capture prey returned to control levels during the six-day recovery period. Sertraline was detected in brain and plasma during the duration of the experiment, though not always in a dose-dependent fashion. While we demonstrated a relationship between time to capture prey and decrease whole brain serotonin levels, the decrease in time to capture prey during the recovery period suggests the serotonin levels in the brain are not solely responsible for the outward behavioral expression observed.


Assuntos
Bass/fisiologia , Química Encefálica/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Inibidores de Captação de Serotonina/toxicidade , Sertralina/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bass/sangue , Bass/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Ecossistema , Comportamento Alimentar/efeitos dos fármacos , Serotonina/metabolismo
5.
Chemosphere ; 256: 126986, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32445995

RESUMO

Systemic neurotoxic insecticides are widely used to control aphid pests worldwide and their potential non-target effects on aphid predators are often unknown. Behavioral responses linked to biological control services are crucial when assessing the compatibility of chemicals with biocontrol organisms. This is particularly relevant for insecticides at low and sublethal concentrations. We studied the acute toxicity and the sublethal effect on the voracity of the generalist predator Harmonia axyridis (Coleoptera: Coccinellidae) caused by the exposure to three systemic insecticides routinely used against aphids. The tested insecticide concentrations were the Lethal Concentration 50% (LC50), 20% (LC20) and 1% (LC1) estimated for the target pest Aphis gossypii (Hemiptera: Aphididae) in a companion study. The survival and the voracity differed among the tested chemicals and concentrations, but only thiamethoxam at LC50 caused a significant predator mortality, and individuals that survived showed a reduced predation rate. The predators showed a density independent functional response after the exposure to most of the insecticide-concentration combinations, while an inverse density dependence of the prey consumption rate was observed for coccinellids exposed to sulfoxaflor and thiamethoxam at their lowest tested concentration. The estimated parameters, i.e., the attack rate and the prey handling time, were affected at higher concentrations by both imidacloprid and sulfoxaflor. These findings stress the importance of carefully evaluating side effects of insecticides at very low concentrations on beneficial arthropods in the risk assessment schemes for sustainable pest control programmes.


Assuntos
Afídeos/efeitos dos fármacos , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Animais , Afídeos/fisiologia , Besouros/efeitos dos fármacos , Dose Letal Mediana , Comportamento Predatório/efeitos dos fármacos , Piridinas , Compostos de Enxofre , Tiametoxam
6.
Arch Environ Contam Toxicol ; 79(1): 156-166, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32266455

RESUMO

The biological effects of endocrine-active compounds and increasing water temperatures as a result of climate change have been studied extensively and independently, but there is a dearth of research to examine the combined effect of these factors on exposed organisms. Recent data suggest that estrogenic exposure and rising ambient temperatures independently impact predator-prey relationships. However, establishing these connections in natural settings is complex. These obstacles can be circumvented if biomarkers of estrogenic exposure in resident fish can predict changes in predator-prey relationships. To test the effects of estrone and temperature, the piscivore bluegill sunfish (Lepomis macrochirus) was exposed for 30 days to estrone at concentrations (90 ± 17.6 ng/L [mean ± standard deviation] and 414 ± 146 ng/L) previously shown to reduce prey-capture success. Exposures were conducted at four temperatures (15 °C, 18 °C, 21 °C, 24 °C) to simulate breeding season ambient temperatures across the natural range of this species. A suite of morphological and physiological biomarkers previously linked to estrogenic exposures were examined. Biomarkers of estrone exposure were more commonly and severely impacted in male fish than in female fish. Notably, the gonadosomatic index was lower and gonads were less mature in exposed males. Additionally, temperature modulated the effects of estrone similarly in males and females with fish exposed at higher temperatures typically exhibiting a decreased morphological index. This study provides evidence that alterations in hepatic function and gonadal function may cause shifts in metabolism and energy allocation that may lead to declining prey capture performance.


Assuntos
Biomarcadores/metabolismo , Disruptores Endócrinos/toxicidade , Estrona/toxicidade , Água Doce/química , Perciformes/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Feminino , Gônadas/efeitos dos fármacos , Gônadas/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Comportamento Predatório/efeitos dos fármacos , Temperatura
7.
Ecotoxicol Environ Saf ; 196: 110497, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247956

RESUMO

Stresses imposed by insecticides and predators are possibly the most rigorous filters to which aquatic organisms are exposed in rivers and lakes associated with agricultural lands. However, their interactive effects on zooplankton communities are still unclear. This study elucidated the zooplankton community response to fish predation, the insecticide chlorpyrifos (CLP), and a combination of both factors, using a 30-day mesocosm experiment. The zooplankton assemblage was influenced by fish presence prior to CLP toxicity. Fish predation reduced microcrustacean density leading to a community dominated by microzooplankton (i.e.: rotifers and copepod nauplii). CLP decreased the species richness in treatments with and without fish, yielding an increase in the abundance of bdelloid rotifers, in the genera Lepadella and Trichocerca. The zooplankton:phytoplankton (<20 µm) ratio decreased substantially when the two stressors, fish predation and insecticide toxicity, were combined. Although CLP dissipated relatively rapidly in the aqueous phase and accumulated in sediment and fish tissue, zooplankton richness was unable to recover. A possible explanation for this could be the inhibitory effect of CLP on resting stage hatchings in the sediment. Therefore, the combined effects of fish predation and CLP might influence zooplankton richness, leading to an assemblage dominated by rotifers that appeared to be resistant to both factors, with a limited capability to control phytoplankton growth. Thus, the effects of natural and anthropogenic stressors should be considered together when assessing community dynamics in aquatic ecosystems.


Assuntos
Peixes/fisiologia , Inseticidas/toxicidade , Comportamento Predatório/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Zooplâncton/fisiologia , Animais , Clorpirifos/toxicidade , Ecossistema , Água Doce/química , Fitoplâncton/efeitos dos fármacos , Fitoplâncton/fisiologia , Zooplâncton/efeitos dos fármacos
8.
Chemosphere ; 250: 126321, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32135440

RESUMO

The lacewing, Chrysoperla sinica, is an important predatory insect, which plays an important role in the integrated pest management of agroforestry pests. However, the extensive use of insecticides negatively affects C. sinica. The acute toxicity, risk level, and, sublethal effects on growth and production, predation ability, protective enzyme activity and genotoxicity of four insecticides: indoxacarb, emamectin benzoate, imidacloprid and lambda-cyhalothrin to C. sinica were studied. The results showed that all four insecticides had lethal toxicity to larvae of C. sinica. Among them, emamectin benzoate had the highest toxicity with LC50 value of 7.41 mg/L. The insecticides also had different effects on the growth and reproduction of C. sinica, of which lambda-cyhalothrin had the greatest impacts. Even at a very low LC1 concentration (3.37 mg/L), it had strong impacts on the growth, reproduction and predatory ability of C. sinica. The four insecticides also caused a decrease in the predatory ability of the lacewing, of which lambda-cyhalothrin had the greatest effect. During the larval stage, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were significantly decreased by the four insecticides. At the pupal and adult stages, the effects of the four insecticides on the activities of protective enzymes were different, and the activities of SOD, CAT and POD decreased or increased. Indoxacarb and lambda-cyhalothrin exposure induced DNA damage in the haemocytes of C. sinica and produced obvious genotoxicity. These results provide important scientific basis for the rational use of these insecticides and the protection and utilization of lacewing.


Assuntos
Insetos/efeitos dos fármacos , Inseticidas/toxicidade , Animais , Ivermectina/análogos & derivados , Ivermectina/toxicidade , Larva/efeitos dos fármacos , Neonicotinoides/toxicidade , Nitrilos , Nitrocompostos/toxicidade , Oxazinas/toxicidade , Comportamento Predatório/efeitos dos fármacos , Pupa/efeitos dos fármacos , Piretrinas , Testes de Toxicidade Aguda
9.
Environ Pollut ; 259: 113952, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31935614

RESUMO

Cyanobacterial blooms are an increasing problem in a more eutrophic world. It is still a challenge to fully understand the influence of cyanobacteria on the interactions between predator and prey at higher trophic levels. The present study was mainly undertaken to understand the inducible anti-predator responses of cladocerans while using cyanobacteria as part of food. Specifically speaking, we focused on the anti-predator strategies of Ceriodaphnia cornuta in response to different predators (fish and Chaoborus larvae) under food with different proportions of Microcystis aeruginosa. The morphological (i.e., body size and the induction of horns) and life history traits (e.g., time to first reproduction, offspring number, and survival time) responses were measured under different proportions of M. aeruginosa (i.e., 0%, 20%, 40%, 60%, 80%, and 100%). Our results showed that both the life history and the inducible anti-predator responses of C. cornuta were significantly affected by different concentrations of M. aeruginosa. Specifically, lower concentrations of Microcystis (20%-60%) can significantly promote the horns induction under Chaoborus predation risks, and higher Microcystis concentrations (60%-100%) tend to enhance reproduction in response to fish predation risks, such as larger body size, decreased time to first reproduction, and increased total offspring number. Additionally, an increasing concentration of M. aeruginosa decreased the ability of C. cornuta to reverse horns when predation risks removed. Our findings indicated that cyanobacteria affecting life history traits and the subsequent indirect effects on anti-predator responses in cladocerans could impact the interactions between predator and prey at higher trophic levels and may consequently contribute to shaping the structure of the community in a cyanobacteria bloom area.


Assuntos
Daphnia/fisiologia , Microcistinas/toxicidade , Microcystis/fisiologia , Comportamento Predatório/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Cladóceros , Peixes
10.
Ecotoxicology ; 29(2): 148-155, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31927677

RESUMO

Stratiolaelaps scimitus (Womersley) and Cosmolaelaps brevistilis (Karg) (Acari: Laelapidae) are predatory mites of soil-inhabiting pests, mainly small insects. Fungus gnats fly species are found in greenhouse strawberry production and may be controlled with predatory mites, being important to know their compatibility with the pesticides used in strawberry crops. In this study, the compatibility of seven commercial pesticides used in strawberry cultivation with the predatory mites S. scimitus and C. brevistilis was assessed in laboratory conditions. Survival and oviposition rates were evaluated between 0.5 and 120 h after treatment (HAT). The results demonstrate that lambda-cyhalothrin treatment resulted in the lowest survival rate for both mites in the first evaluations, being moderately harmful, while spinetoran was slightly harmful to C. brevistilis. On the other hand, abamectin, azadirachtin, azoxystrobin + difenoconazole, iprodione and thiamethoxam were harmless for both mites and, oviposition rate was significantly different only at 72 and 120 HAT for S. scimitus and C. brevistilis respectively. These results may be used to develop guidelines for the adoption of selective pesticides in integrated pest management programs that conserves predatory mites.


Assuntos
Fragaria/fisiologia , Ácaros/fisiologia , Controle Biológico de Vetores/métodos , Praguicidas , Animais , Comportamento Predatório/efeitos dos fármacos
11.
Ecotoxicol Environ Saf ; 187: 109849, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31677571

RESUMO

Harmonia axyridis is an important predator of several pest species and is part of many Integrated Pest Management (IPM) programs. To assess the risks of pesticide application to H. axyridis, we studied the effects of sulfoxaflor on H. axyridis larvae. At 72 h after treatment, the acute toxicity LR50 was 311.9476 g a. i. ha-1 by the residual contact method. This result indicated low-contact toxicity against second-instar H. axyridis larvae. The LR50 of the F1 generation decreased from 69.96 to 36.41 g a. i. ha-1 in a long-term toxicity test. The daily hazard quotient (HQ) for H. axyridis larvae lowered the safety threshold value in the first 5 d. However, the HQ values were greater than 2 during days 6-18 after sulfoxaflor treatments. We determined the No Observed Effect Application Rates of sulfoxaflor on the survival (<11.25 g a. i. ha-1), duration of larval and pupal stages (45 g a. i. ha-1), adult stage (90 g a. i. ha-1), total pre-oviposition period, adult pre-oviposition period (45 g a. i. ha-1), and reproduction (11.25 g a. i. ha-1). Pupation, adult emergence, and eggs counts of H. axyridis were reduced after sulfoxaflor treatments. The predation ability and population demography parameters were significantly impaired by higher application rates. At 90 g a. i. ha-1 or less, sulfoxaflor was slightly harmful to H. axyridis but a rate of 180 g a. i. ha-1 was moderately harmful. These results demonstrated that sulfoxaflor is harmful to H. axyridis when applied at high application rates.


Assuntos
Besouros/efeitos dos fármacos , Larva/efeitos dos fármacos , Resíduos de Praguicidas/toxicidade , Pupa/efeitos dos fármacos , Piridinas/toxicidade , Compostos de Enxofre/toxicidade , Animais , Besouros/fisiologia , Relação Dose-Resposta a Droga , Feminino , Larva/fisiologia , Dose Letal Mediana , Controle de Pragas , Comportamento Predatório/efeitos dos fármacos , Pupa/fisiologia , Reprodução/efeitos dos fármacos , Testes de Toxicidade
12.
Gen Comp Endocrinol ; 286: 113299, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606464

RESUMO

State-dependent foraging theory posits that animals should make foraging decisions based on energetic condition, where animals with fewer energetic reserves prioritize foraging over other behaviors, including antipredator behaviors. However, few studies have investigated these trade-offs at an individual level in wild, free-ranging animals. We investigated the relationships between internal condition and behavior in a wild mammal, the vicuña (Vicugna vicugna), which makes state-dependent decisions about the use of two habitats with different characteristics that contribute to their internal condition. Using non-invasively collected fecal samples, we measured glucocorticoid metabolites (GCMs) and thyroid hormones (THs) as indicators of combined stress (predation and nutritional), and just nutritional stress, respectively. We video recorded 20-minute behavioral observations and focused on behaviors which often demand a trade-off between energy acquisition and antipredator behaviors-vigilance and foraging. We found differences in expression of these behaviors between the two sites but found no relationships between physiological parameters (GCMs and THs) and behavior (vigilance and foraging) at either site. We suggest that state-dependent foraging may be difficult to observe in large mammals under baseline conditions and that GCMs and THs may be insensitive to small changes in stress stimuli at this scale, and where these wild animals have the entire suite of behavioral responses available to them.


Assuntos
Glucocorticoides/metabolismo , Comportamento Predatório/efeitos dos fármacos , Tri-Iodotironina/metabolismo , Animais , Camelídeos Americanos
13.
Elife ; 82019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31841109

RESUMO

Insect herbivores are frequently reported to metabolize plant defense compounds, but the physiological and ecological consequences are not fully understood. It has rarely been studied whether such metabolism is genuinely beneficial to the insect, and whether there are any effects on higher trophic levels. Here, we manipulated the detoxification of plant defenses in the herbivorous pest diamondback moth (Plutella xylostella) to evaluate changes in fitness, and additionally examined the effects on a predatory lacewing (Chrysoperla carnea). Silencing glucosinolate sulfatase genes resulted in the systemic accumulation of toxic isothiocyanates in P. xylostella larvae, impairing larval development and adult reproduction. The predatory lacewing C. carnea, however, efficiently degraded ingested isothiocyanates via a general conjugation pathway, with no negative effects on survival, reproduction, or even prey preference. These results illustrate how plant defenses and their detoxification strongly influence herbivore fitness but might only subtly affect a third trophic level.


Assuntos
Fatores Biológicos/metabolismo , Herbivoria/efeitos dos fármacos , Holometábolos/efeitos dos fármacos , Plantas/imunologia , Plantas/metabolismo , Animais , Fatores Biológicos/toxicidade , Holometábolos/crescimento & desenvolvimento , Inativação Metabólica , Isotiocianatos/metabolismo , Isotiocianatos/toxicidade , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Comportamento Predatório/efeitos dos fármacos , Reprodução/efeitos dos fármacos
14.
Sci Rep ; 9(1): 15676, 2019 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-31666603

RESUMO

Nanoparticle contaminants enter aquatic ecosystems and are transported along the stream network. Here, we demonstrate a novel pathway for the return of nanoparticles from aquatic to terrestrial ecosystems via cross-boundary subsidies. During their emergence, trichopteran caddisflies carried titanium dioxide and gold nanoparticles into their terrestrial life stages. Moreover, their emergence was delayed by ≤30 days, and their energy reserves were depleted by ≤25%. Based on worst case estimates, it is suggested that terrestrial predators, such as bats feeding on aquatic prey, may ingest up to three orders of magnitude higher gold levels than anticipated for humans. Additionally, terrestrial predator species may suffer from alterations in the temporal availability and nutritional quality of their prey. Considering the substantial transfer of insect biomass to terrestrial ecosystems, nanoparticles may decouple aquatic and terrestrial food webs with important (meta-)ecosystem level consequences.


Assuntos
Quirópteros/fisiologia , Ecossistema , Hidrobiologia , Nanopartículas Metálicas/química , Animais , Biomassa , Cadeia Alimentar , Ouro/química , Humanos , Insetos/fisiologia , Comportamento Predatório/efeitos dos fármacos , Aranhas/efeitos dos fármacos
15.
Aquat Toxicol ; 216: 105310, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31580997

RESUMO

Pesticide mixtures are increasingly used to fight pest species that developed resistance to pesticides. To assess the pesticide control efficiency and to reduce ecological damage to non-target species, it is important to quantify the effect of these mixtures and compare them with the effect of their single pesticides on pest species, non-target species and their predator-prey interactions. We studied the effects of the chemical pesticide chlorpyrifos (CPF), the biopesticide Bacillus thuringiensis israelensis (Bti) and their mixture both on the direct mortality and on the mortality by predation. We focused on larvae of a CPF-resistant and a non-resistant strain of the vector mosquito Culex quinquefasciatus and its predator, the pygmy backswimmer Plea minutissima. In the CPF-Bti mixture, both pesticides interacted antagonistically for direct mortality. Exposure to the mixture caused equal direct mortality and equal mortality by predation in both strains. As expected, exposure to CPF resulted in less direct mortality and less mortality by predation in the CPF-resistant mosquito strain compared to the non-resistant strain. Notably, Bti caused a higher mortality in the mosquito larvae of the CPF-resistant strain compared to the non-resistant strain. Furthermore, the predator killed more mosquito larvae of the resistant strain compared to the non-resistant strain when exposed before to Bti alone. These observations identify a novel cost of resistance to a chemical pesticide in terms of increased vulnerability to a biopesticide.


Assuntos
Agentes de Controle Biológico/toxicidade , Praguicidas/toxicidade , Comportamento Predatório/efeitos dos fármacos , Animais , Bacillus thuringiensis/efeitos dos fármacos , Clorpirifos/toxicidade , Culex/efeitos dos fármacos , Reação de Congelamento Cataléptica/efeitos dos fármacos , Heterópteros/efeitos dos fármacos , Larva/efeitos dos fármacos , Modelos Lineares , Natação , Poluentes Químicos da Água/toxicidade
16.
Aquat Toxicol ; 216: 105312, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31563086

RESUMO

Many coastal systems have been experiencing the effects of non-chemical and chemical anthropological stressors through respective increases in surface water temperatures and rainstorm-derived runoff events of pyrethroid pesticide movement into waterways such as the San Francisco Bay-Delta. Salmonid populations in the Bay-Delta have been dramatically declining in recent decades. Therefore, the aim of this study was to investigate the interactive effects of bifenthrin, a pyrethroid insecticide, and increasing water temperatures on targeted neuroendocrine and behavioral responses in Chinook salmon (Oncorhynchus tshawytscha) parr (10- month post-hatch). Parr were reared at 11 °C, 16.4 °C, or 19 °C for 14 days and, in the final 96 h of rearing, exposed to nominal concentrations of 0, 0.15, or 1.5 µg/L bifenthrin. A predatory avoidance Y-Maze behavioral assay was conducted immediately following exposures. Parr were presented a choice of clean or odorant zones, and locomotive behavior was recorded. Thyroid hormones (T3 and T4), estradiol, and testosterone were quantified within plasma using ELISAs, and the expression of brain hormone and dopamine receptor genes were also evaluated by qPCR. Brain dopamine levels were analyzed by LC/MS. No significant changes were observed in brain transcripts or plasma hormone concentrations with bifenthrin or increasing temperature. However, temperature did significantly lower brain dopamine levels in fish reared at 19 °C compared to 11 °C controls, but was unaltered by bifenthrin treatment. In contrast, parr reared at 11 °C and exposed to 1.5 µg/L bifenthrin spent significantly less time avoiding a predatory odorant compared to vehicle controls reared at 11 °C. The 16.4 °C and 1.5 µg/L-treated fish spent significantly more time in the neutral arm compared to the odorant and clean arms, as well as spending significantly less time in the clean arm compared to the 11 °C control fish. These results suggest that the interaction of temperature and bifenthrin may be adversely impacting predator-avoidance behavior, which may not be related to dopaminergic responses.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Piretrinas/toxicidade , Salmão/fisiologia , Temperatura , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Dopamina/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônios/metabolismo , Poluentes Químicos da Água/toxicidade
17.
Mol Plant ; 12(10): 1315-1324, 2019 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-31557534

RESUMO

Bird predation during seed maturation causes great loss to agricultural production. In this study, through GWAS analysis of a large-scale sorghum germplasm diversity panel, we identified that Tannin1, which encodes a WD40 protein functioning in the WD40/MYB/bHLH complex, controls bird feeding behavior in sorghum. Metabolic profiling analysis showed that a group of sorghum accessions preferred by birds contain mutated tan1-a/b alleles and accumulate significantly lower levels of anthocyanins and condensed tannin compounds. In contrast, a variety of aromatic and fatty acid-derived volatiles accumulate at significantly higher levels in these bird-preference accessions. We subsequently conducted both sparrow feeding and sparrow volatile attractant assays, which confirmed, respectively, the antifeedant and attractant functions of these differentially accumulated metabolites. In addition, the connection between the biosynthesis pathway of anthocyanin and proanthocyanidin and the pathway of fatty acid-derived volatile biosynthesis was demonstrated by discovering that Tannin1 complex modulates fatty acid biosynthesis by regulating the expression of SbGL2 in sorghum, thus affecting the accumulation of fatty acid-derived volatiles. Taken together, our study identified Tannin1 as the gene underlying the major locus controlling bird feeding behavior in sorghum, illustrating an example of the identification of an ecologically impactful molecular mechanism from field observation and providing significant insights into the chemistry of bird-plant ecological interactions.


Assuntos
Aves , Ácidos Graxos/química , Comportamento Alimentar , Proteínas de Plantas/metabolismo , Polifenóis/biossíntese , Sorghum/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Animais , Comportamento Alimentar/efeitos dos fármacos , Estudo de Associação Genômica Ampla , Comportamento Predatório/efeitos dos fármacos , Sorghum/genética , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/farmacologia
18.
Ecotoxicol Environ Saf ; 184: 109669, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31536847

RESUMO

Cotton hosts a variety of arthropod pests requiring intensive control mostly with insecticides, which in turn may impact beneficial insects and the environment. Therefore, insect control in cotton fields preconizes the use of selective insecticides that offer pest control but conserve natural enemies. In this work, we measured the impact of recommended insecticides on the abundance of predatory insects and predation upon sentinel preys in the field. Further, the survival of four key selected predatory insects of cotton ecosystem, representing chewing and sucking feeding habits and different pest species attacked [Chrysoperla externa Hagen, Eriopis connexa (Germar), Podisus nigrispinus (Dallas) and Orius insidiosus (Say)], were assessed when exposed to the dried residues of the tested insecticides. Mortality of sentinel prey caused by natural enemies was higher in areas treated with selective insecticides relative to the non-selective ones, and most of time similar to the untreated areas. Furthermore, areas treated with non-selective insecticides experienced prolonged impact between sprays depending on the insecticide applied. Seasonal abundance of predatory insects was 2× greater in fields under selective and untreated fields compared to those under non-selective recommendation. Survival of predators exposed to the dried residues of the selective insecticides pymetrozine, chlorantraniliprole, pyriproxyfen, and cyantraniliprole were greater than when exposed to the non-selective lambda-cyhalothrin, malathion, dimethoate, and thiamethoxam. Among the non-selective insecticides, malathion and dimethoate exhibited shorter residual time compared to the thiamethoxam and lambda-cyhalothrin + thiamethoxam. Therefore, the recommendation of selective insecticides provides benefits for cotton pest management by maintaining the action of the natural enemies present in the field.


Assuntos
Besouros/efeitos dos fármacos , Gossypium/crescimento & desenvolvimento , Heterópteros/efeitos dos fármacos , Controle de Insetos/métodos , Inseticidas/farmacologia , Comportamento Predatório/efeitos dos fármacos , Animais , Ecossistema , Modelos Teóricos
19.
Nat Commun ; 10(1): 3579, 2019 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-31395863

RESUMO

It is thought that fungi protect themselves from predation by the production of compounds that are toxic to soil-dwelling animals. Here, we show that a nontoxic pigment, the bis-naphthopyrone aurofusarin, protects Fusarium fungi from a wide range of animal predators. We find that springtails (primitive hexapods), woodlice (crustaceans), and mealworms (insects) prefer feeding on fungi with disrupted aurofusarin synthesis, and mealworms and springtails are repelled by wheat flour amended with the fungal bis-naphthopyrones aurofusarin, viomellein, or xanthomegnin. Predation stimulates aurofusarin synthesis in several Fusarium species and viomellein synthesis in Aspergillus ochraceus. Aurofusarin displays low toxicity in mealworms, springtails, isopods, Drosophila, and insect cells, contradicting the common view that fungal defence metabolites are toxic. Our results indicate that bis-naphthopyrones are defence compounds that protect filamentous ascomycetes from predators through a mechanism that does not involve toxicity.


Assuntos
Artrópodes/efeitos dos fármacos , Aspergillus ochraceus/fisiologia , Fusarium/fisiologia , Naftoquinonas/farmacologia , Pigmentos Biológicos/farmacologia , Adaptação Fisiológica , Animais , Artrópodes/fisiologia , Preferências Alimentares/efeitos dos fármacos , Naftoquinonas/metabolismo , Pigmentos Biológicos/metabolismo , Comportamento Predatório/efeitos dos fármacos
20.
Behav Processes ; 166: 103905, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31310793

RESUMO

Globally, native predators and scavengers are threatened through the incidence of illegal poisoning due to increasing human-wildlife conflicts. The use of conditioned taste aversion (CTA) may mitigate such conflicts. CTA is a robust learning paradigm that occurs when animals associate a food with a discomfort induced by a chemical, thereby avoiding that food in subsequent encounters. We reviewed the potential of 167 chemical compounds to be used in CTA, considering effects, margin of safety, accessibility, and detectability. After the review, 15 compounds fulfilled the required characteristics, but only five (thiabendazole, thiram, levamisole, fluconazole and fluralaner) were finally selected to be tested in CTA assays with dogs. Of the tested compounds, thiabendazole, thiram and levamisole caused target food rejection by dogs and reduced the time spent eating during post-conditioning. However, despite being microencapsulated, levamisole appeared to be detectable by dogs, whereas thiram and thiabendazole were not. Fluconazole and fluralaner did not produce any CTA effect. Thiabendazole, thiram and levamisole can therefore induce CTA, and thus are potential candidates as aversive compounds for wildlife management. Thiram is an undetectable, relatively safe and accessible compound that can induce CTA in canids, and opens new possibilities to develop methods of non-lethal predation control.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Paladar , Animais , Animais Selvagens , Condicionamento Clássico/efeitos dos fármacos , Cães , Fluconazol/farmacologia , Isoxazóis/farmacologia , Levamisol/farmacologia , Masculino , Tiabendazol/farmacologia , Tiram/farmacologia
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