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1.
Ecotoxicology ; 29(3): 359-374, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32124147

RESUMO

Bumblebees exposed to neonicotinoid pesticides collect less pollen on foraging trips. Exposed bumblebees are also slower to learn to handle flowers, which may account for reduced pollen collection. It is unclear, however, why neonicotinoid exposure slows learning to handle flowers. We investigated the effect of imidacloprid, a neonicotinoid pesticide, on bumblebee motor learning using a lab model of flower handling. Bumblebees learned to invert inside a narrow tube and lift a petal-shaped barrier to reach a reward chamber. Imidacloprid-exposed bumblebees showed a dose-dependent delay to solve the task, which resulted from reduced switching between behavioural strategies and a subsequent delay in use of the successful strategy. This effect was consistent in colonies exposed at 10 but not 2.6 ppb, suggesting a variable effect on individuals at lower doses. These results help to explain why exposed bumblebees are slow to learn to handle flowers and collect less pollen on foraging trips.


Assuntos
Abelhas/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Animais , Flores
2.
Ecotoxicology ; 29(3): 246-257, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32170464

RESUMO

Africanized and wild bees are sensitive to synthetic insecticides, but may not be sensitive to botanical extracts. In this work, we evaluated the toxicity of botanical extracts with homemade preparations used in agroecological crops and their constituents on the bees Apis mellifera and Partamona helleri. Toxicity bioassays of adult bees were done by means of oral exposure and ingestion, using the insecticide imidacloprid as a positive control. Dietary consumption, respiration rate and bee flight were evaluated as sublethal parameters. Although some extracts were toxic to bees, survival was always higher compared to the results obtained with the imidacloprid, which was lethal to 100% of bees. In dietary consumption, P. helleri consumed less (5 mg/bee) in 3 h than A. mellifera (11 mg/bee), and P. helleri consumed less (7 mg/bee) in 24 h than A. mellifera (22 mg/bee). There was no difference in consumption of food containing plant extracts or food containing water only. We did not detect any adverse effects of the botanical extracts on bee respiration rates or flight. The major constituent of N. tabacum is nicotine (8.4-15.1%), in A. americana it is ß-caryophyllene (11.3%), and in A. colubrina, lupeol (12.2%). Imidacloprid and nicotine were more toxic to bees (LC50 ≤ 1.3 and LC50 ≤ 44.3). Botanical extracts were selective to A. mellifera and the native bee P. helleri, and therefore, have the potential for ecofriendly pest control.


Assuntos
Abelhas/fisiologia , Inseticidas/toxicidade , Extratos Vegetais/toxicidade , Animais , Dieta , Dose Letal Mediana , Neonicotinoides , Nitrocompostos
3.
Ecotoxicology ; 29(3): 237-245, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32060669

RESUMO

Pollinator decline worldwide is well-documented; globally, chemical pesticides (especially the class of pesticides known as neonicotinoids) have been implicated in hymenopteran decline, but the mechanics and drivers of population trends and dynamics of wild bees is poorly understood. Declines and shifts in community composition of bumble bees (Bombus spp.) have been documented in North America and Europe, with a suite of lethal and sub-lethal effects of pesticides on bumble bee populations documented. We employ a mathematical model parameterized with values taken from the literature that uses differential equations to track bumble bee populations through time in order to attain a better understanding of toxicant effects on a developing colony of bumble bees. We use a delay differential equation (DDE) model, which requires fewer parameter estimations than agent-based models while affording us the ability to explicitly describe the effect of larval incubation and colony history on population outcomes. We explore how both lethal and sublethal effects such as reduced foraging ability may combine to affect population outcomes, and discuss the implications for the protection and conservation of ecosystem services.


Assuntos
Abelhas/fisiologia , Monitoramento Ambiental , Substâncias Perigosas/toxicidade , Agricultura , Animais , Ecossistema , Neonicotinoides/toxicidade , Praguicidas/toxicidade , Polinização
4.
Nat Commun ; 11(1): 576, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996690

RESUMO

Urbanisation is an important global driver of biodiversity change, negatively impacting some species groups whilst providing opportunities for others. Yet its impact on ecosystem services is poorly investigated. Here, using a replicated experimental design, we test how Central European cities impact flying insects and the ecosystem service of pollination. City sites have lower insect species richness, particularly of Diptera and Lepidoptera, than neighbouring rural sites. In contrast, Hymenoptera, especially bees, show higher species richness and flower visitation rates in cities, where our experimentally derived measure of pollination is correspondingly higher. As well as revealing facets of biodiversity (e.g. phylogenetic diversity) that correlate well with pollination, we also find that ecotones in insect-friendly green cover surrounding both urban and rural sites boost pollination. Appropriately managed cities could enhance the conservation of Hymenoptera and thereby act as hotspots for pollination services that bees provide to wild flowers and crops grown in urban settings.


Assuntos
Abelhas/fisiologia , Ecologia , Insetos/fisiologia , Polinização , Urbanização , Animais , Abelhas/classificação , Biodiversidade , Cidades , Dípteros , Ecossistema , Flores , Alemanha , Himenópteros , Insetos/classificação , Lepidópteros , Filogenia
5.
Chemosphere ; 242: 125145, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31678852

RESUMO

Neonicotinoid insecticides are currently of major concern for the health of wild and managed insects that provide key ecosystem services like pollination. Even though sublethal effects of neonicotinoids are well known, there is surprisingly little information on how they possibly impact developmental stability, and to what extent genetics are involved. This holds especially true for haploid individuals because they are hemizygous at detoxification loci and may be more susceptible. Here we take advantage of haplodiploidy in Western honey bees, Apis mellifera, to show for the first time that neonicotinoids affect developmental stability in diploid females (workers), and that haploid males (drones) are even more susceptible. Phenotypic fore wing venation abnormalities and fluctuating wing asymmetry, as measures of developmental instability, were significantly increased under field-realistic neonicotinoid-exposure of colonies. The higher susceptibility of haploid drones suggests that heterozygosity can play a key role in the ability to buffer the sublethal effects of neonicotinoids. Aiming to improve conservation efforts, our findings highlight the urgent need to better understand the role that genetics plays at enabling non-target organisms to cope with insecticide exposure.


Assuntos
Abelhas/fisiologia , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Animais , Ecossistema , Feminino , Haploidia , Inseticidas/análise , Masculino , Neonicotinoides/análise , Nitrocompostos , Polinização , Asas de Animais
6.
Environ Pollut ; 256: 113443, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733951

RESUMO

During their lifetime honey bees (Apis mellifera) rarely experience optimal conditions. Sometimes, a simultaneous action of multiple stressors, natural and chemical, results in even greater effect than of any stressor alone. Therefore, integrative investigations of different factors affecting honey bees have to be carried out. In this study, adult honey bees exposed to thiamethoxam in larval and/or adult stage and infected with Nosema ceranae were examined. Newly emerged bees from colonies, non-treated or treated with thiamethoxam, were organized in six groups and kept in cages. Thiamethoxam treated bees were further exposed to either thiamethoxam or Nosema (groups TT and TN), or simultaneously to both (group TTN). Newly emerged bees from non-treated colonies were exposed to Nosema (group CN). From both, treated and non-treated colonies two groups were organized and further fed only with sugar solution (groups C and TC). Here, we present the expression profile of 19 genes in adult worker honey bees comprising those involved in immune, detoxification, development and apoptosis response. Results showed that gene expression patterns changed with time and depended on the treatment. In group TC at the time of emergence the majority of tested genes were downregulated, among which nine were significantly altered. The same gene pattern was observed on day six, where the only significantly upregulated gene was defensin-1. On day nine most of analyzed genes in all experimental groups showed upregulation compared to control group, where upregulation of antimicrobial peptide genes abaecin, defensin-1 and defensin-2 was significant in groups TT and TTN. On day 15 we observed a similar pattern of expression in groups TC and TT exposed to thiamethoxam only, where most of the detoxification genes were downregulated. Additionally RNA loads of Nosema and honey bee viruses were recorded. We detected a synergistic interaction of thiamethoxam and Nosema, reflected in lowest honey bee survival.


Assuntos
Abelhas/fisiologia , Inseticidas/toxicidade , Nosema , Tiametoxam/toxicidade , Animais , Peptídeos Catiônicos Antimicrobianos , Abelhas/efeitos dos fármacos , Abelhas/microbiologia , Expressão Gênica , Proteínas de Insetos , Larva/efeitos dos fármacos , Larva/microbiologia , Larva/fisiologia , Microsporidiose/veterinária
7.
Environ Pollut ; 256: 113420, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31813703

RESUMO

Pesticide exposure is regarded as a contributing factor to the high gross loss rates of managed colonies of Apis mellifera. Pesticides enter the hive through contaminated nectar and pollen carried by returning forager honey bees or placed in the hive by beekeepers when managing hive pests. We used an in vitro rearing method to characterize the effects of seven pesticides on developing brood subjected dietary exposure at worse-case environmental concentrations detected in wax and pollen. The pesticides tested included acaricides (amitraz, coumaphos, fluvalinate), insecticides (chlorpyrifos, imidacloprid), one fungicide (chlorothalonil), and one herbicide (glyphosate). The larvae were exposed chronically for six days of mimicking exposure during the entire larval feeding period, which is the worst possible scenario of larval exposure. Survival, duration of immature development, the weight of newly emerged adult, morphologies of the antenna and the hypopharyngeal gland, and gene expression were recorded. Survival of bees exposed to amitraz, coumaphos, fluvalinate, chlorpyrifos, and chlorothalonil was the most sensitive endpoint despite observed changes in many developmental and physiological parameters across the seven pesticides. Our findings suggest that pesticide exposure during larvae development may affect the survival and health of immature honey bees, thus contributing to overall colony stress or loss. Additionally, pesticide exposure altered gene expression of detoxification enzymes. However, the tested exposure scenario is unlikely to be representative of real-world conditions but emphasizes the importance of proper hive management to minimize pesticide contamination of the hive environment or simulates a future scenario of increased contamination.


Assuntos
Abelhas/fisiologia , Poluentes Ambientais/toxicidade , Praguicidas/toxicidade , Animais , Clorpirifos , Cumafos , Fungicidas Industriais/toxicidade , Herbicidas/toxicidade , Inativação Metabólica , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Neonicotinoides , Nitrilos , Nitrocompostos , Pólen/efeitos dos fármacos , Piretrinas , Toluidinas
8.
Ecotoxicology ; 29(1): 119-128, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31863232

RESUMO

Use of pesticides in agroecosystems is considered a major cause of bees diversity losses in the Neotropics, where Plebeia emerina (Friese) and Tetragonisca fiebrigi (Schwarz) (Hymenoptera: Apidae: Meliponini) are wild pollinators of native and crop plants. The aim of this study was to know the acute lethal toxicity of acetamiprid, malathion, phosmet and spinosad insecticides on P. emerina and T. fiebrigi. We obtained the mean concentration and mean lethal dose (LC50 and LD50) and the mean survival of workers after oral and topical exposure to insecticides, respectively. The LC50 values (ng a.i./µl of diet) and the decreasing order of toxicity for P. emerina was spinosad (4.96) > malathion (18.75) > phosmet (97.33) > acetamiprid (4204.06), and for T. fiebrigi also was spinosad (5.65) > malathion (8.39) > phosmet (53.91) > acetamiprid (9841.32), when orally exposed. The LD50 values (ng a.i./bee) and the decreasing order of toxicity for P. emerina was spinosad (1.90) > malathion (10.90) > phosmet (19.54) > acetamiprid (6216.55) and for T. fiebrigi was malathion (29.29) ≥ spinosad (29.79) > phosmet (41.95) > acetamiprid (1421.23), when topically exposed. The mean survival (hours) of contaminated bees by malathion, phosmet, and spinosad, was 11.81, 7.20, and 12.32 for P. emerina and 8.55, 7.20, and 13.34 for T. fiebrigi when orally exposed; and was 4.87, 9.87 and 11.17 for P. emerina, and 4.87, 4.76, and 19.05 for T. fiebrigi when topically exposed. Malathion, phosmet, and spinosad were highly toxic, while acetamiprid was moderately toxic. Our results indicated that the insecticides tested, mainly malathion, phosmet, and spinosad may be harmful to P. emerina and T. fiebrigi, making it essential to propose measures to minimize their impact on wild pollinators.


Assuntos
Abelhas/fisiologia , Himenópteros/fisiologia , Inseticidas/toxicidade , Animais , Abelhas/efeitos dos fármacos , Combinação de Medicamentos , Himenópteros/efeitos dos fármacos , Dose Letal Mediana , Macrolídeos , Malation , Neonicotinoides , Polinização
9.
J Chem Ecol ; 46(2): 150-162, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31872313

RESUMO

The botanical source of Brazilian green propolis (BGP) is Baccharis dracunculifolia DC, which interacts not only with Apis mellifera, but also with galling insects. In the last decade, because of green propolis´ important biologic activities, the international demand for BGP overcame the production capacity, consequently, new approaches are required to increase this production. Hence, the understanding of the chemical ecology interactions of B. dracunculifolia with galls and bees in field conditions may provide insights to increase BGP's production. A "bee pasture" experiment aiming to better understand this plant-insect interaction was therefore performed. For that, 48 B. dracunculifolia individuals, being 24 females and 24 males, were cultivated and investigated for the following parameters: (1) phenolic and volatile compounds in both B. dracunculifolia leaves and green propolis, (2) environmental variables, (3) visiting rate by bees, (4) time of resin collection, and (5) number of galls. Regression analyses by independent linear mixed-effect models were run to correlate phenolic and volatile compounds concentration with the environmental and field variables. Significant differences in chemical profile and field variables were observed between male and female plants. Male plants showed higher infestation by galling insects while female plants showed higher number of visiting bees, time of resin collection and terpenes concentration, contributing to the differences observed in the field. The obtained results suggest that increasing the percentage of female B. dracunculifolia plants in the field may attract more bees and therefore enhance propolis production.


Assuntos
Baccharis/química , Abelhas/fisiologia , Própole/química , Animais , Baccharis/metabolismo , Comportamento Animal/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Feminino , Masculino , Espectrometria de Massas , Fenol/análise , Fenol/química , Fenol/farmacologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Tumores de Planta/parasitologia , Própole/análise , Própole/farmacologia , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/farmacologia
10.
Ecotoxicol Environ Saf ; 190: 110100, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31869716

RESUMO

The neonicotinoid insecticide acetamiprid (ACT) and seven pesticides [abamectin (ABA), emamectin benzoate (EMB), dicrotophos (DIC), bifenthrin (BIF), cypermethrin (CYP), lambda-cyhalothrin (LCY) and tetraconazole (TET)] are widely applied agrochemicals worldwide. Since most previous studies on these pesticides are performed merely based on toxicity tests with individual active ingredients, only finite knowledge is available on the mixture toxicities of these formulated compounds to crop pollinators. In this study, we examined their toxicities of binary, ternary, quaternary, quinquenary, senary, septenary and octonary mixtures to honey bee (Apis mellifera L.) with feeding toxicity test. Results showed that EMB and ABA had the highest toxicities to A. mellifera with LC50 values of 0.033 (0.028-0.038) and 0.047 (0.039-0.056) µg a. i. mL-1 after exposure for 7 days, respectively, followed by DIC with an LC50 value of 1.22 (1.01-1.41) µg a. i. mL-1. In contrast, relatively low toxicities were found from pyrethroid insecticides, ACT, and TET with their LC50 values ranged from 44.76 (38.75-50.89) to 251.7 (198.4-297.3) µg a. i. mL-1. Most of pesticide mixtures containing ACT and TET elicited synergistic interactions to honey bees. Besides, four pesticide mixtures of ACT + BIF, ACT + BIF + CYP, ACT + BIF + LCY and ACT + CYP + DIC + EMB also displayed synergistic effects. Among 98 tested binary to octonary mixtures of ACT in combination with seven pesticides, 44.90% of combinations exhibited synergistic effects on honey bees. Considering ACT was permitted to use on flowering crops, more attention should be paid to its application in the fields due to the synergistic effects of ACT in combination with other pesticides on A. mellifera under laboratory conditions.


Assuntos
Abelhas/fisiologia , Neonicotinoides/toxicidade , Praguicidas/toxicidade , Animais , Clorobenzenos , Inseticidas/toxicidade , Nitrilos , Polinização/efeitos dos fármacos , Piretrinas , Testes de Toxicidade , Triazóis
11.
Ecotoxicol Environ Saf ; 190: 110101, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31874407

RESUMO

Varroa mites often inflict heavy losses on the global bee industry and there are few effective control options. Among these methods to control mites, pesticides are extensively used as a cheap, easy to use, and high-efficiency control measure. However, bees are sensitive to many pesticides; thus, a balance between losses induced by drugs and maximum benefits are important for beekeeping and risk assessment. In this study, the effects of flumethrin, a pyrethroid miticide used on bee colonies, was evaluated using bee larvae reared in vitro. We found that flumethrin induced significant mortality during larval metamorphosis and adult emergence. After continuous exposure during the larval stage, significant changes were observed in antioxidative enzymes (SOD and CAT), lipid peroxidation (MDA, LPO, and POD), and detoxification enzymes (GSH, GST, and GR) in the late instar larvae before pupation. It is also noteworthy that flumethrin significantly regulated the expression of immune (Basket and Dscam) and developmental (Amems, Amhex10869, Vtg and Mfe) genes in larvae, which influences can also be found in the subsequent pupae and adult stages. These findings indicate that flumethrin itself is toxic to bee larvae and has potential risks during colony development. Bees are important pollinators and the sustainable and healthy development of colonies is the foundation of pollinating success for agricultural production. This study would provide some useful thinking for pesticides application techniques and processes in risk assessment of pesticides to bee larvae, even colony.


Assuntos
Abelhas/fisiologia , Praguicidas/toxicidade , Piretrinas/toxicidade , Estresse Fisiológico , Animais , Criação de Abelhas , Mel , Larva/efeitos dos fármacos , Praguicidas/análise , Polinização , Pupa/crescimento & desenvolvimento , Piretrinas/análise , Varroidae
12.
Insect Sci ; 27(1): 133-142, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29740981

RESUMO

Over 50 genera of bees release pollen from flower anthers using thoracic vibrations, a phenomenon known as buzz-pollination. The efficiency of this process is directly affected by the mechanical properties of the buzzes, namely the duration, amplitude, and frequency. Nonetheless, although the effects of the former two properties are well described, the role of buzz frequency on pollen release remains unclear. Furthermore, nearly all of the existing studies describing vibrational properties of natural buzz-pollination are limited to bumblebees (Bombus) and carpenter bees (Xylocopa) constraining our current understanding of this behavior and its evolution. Therefore, we attempted to minimize this shortcoming by testing whether flower anthers exhibit optimal frequency for pollen release and whether bees tune their buzzes to match these (optimal) frequencies. If true, certain frequencies will trigger more pollen release and lighter bees will reach buzz frequencies closer to this optimum to compensate their smaller buzz amplitudes. Two strategies were used to test these hypotheses: (i) the use of (artificial) vibrational playbacks in a broad range of buzz frequencies and amplitudes to assess pollen release by tomato plants (Solanum lycopersicum L.) and (ii) the recording of natural buzzes of Neotropical bees visiting tomato plants during pollination. The playback experiment indicates that although buzz frequency does affect pollen release, no optimal frequency exists for that. In addition, the recorded results of natural buzz-pollination reveal that buzz frequencies vary with bee genera and are not correlated with body size. Therefore, neither bees nor plants are tuned to optimal pollen release frequencies. Bee frequency of buzz-pollination is a likely consequence of the insect flight machinery adapted to reach higher accelerations, while flower plant response to buzz-pollination is the likely result of its pollen granular properties.


Assuntos
Abelhas/fisiologia , Lycopersicon esculentum/fisiologia , Polinização , Animais , Brasil , Pólen , Especificidade da Espécie , Vibração
13.
Sci Total Environ ; 700: 134500, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31627045

RESUMO

Flumethrin is a typical pyrethroid varroacide widely used for mite control in beekeeping worldwide. Currently, information on the toxicological characteristics of flumethrin on bees at sublethal concentrations is still lacking. To fill this gap in information, we performed a 48-h acute oral and 14-day chronic toxicity testing of flumethrin in newly emerged adult honey bees under laboratory conditions. Results showed that flumethrin had high acute toxicity to honey bees with a 48-h LD50 of 0.47 µg/bee (95% CI, 0.39 ∼ 0.57 µg/bee), which is higher than that of many other commercial pyrethroid insecticides, but lower than that of tau-fluvalinate. After 14 days of chronic exposure to flumethrin at 0.01, 0.10, and 1.0 mg/L, significant antioxidant response, detoxification, immune reaction, and apoptosis were observed in the midguts. These findings indicated that flumethrin had potential risks to bees, and it can disturb the homeostasis of bees at sublethal concentrations under longer exposure conditions. Flumethrin is highly lipophilic and easy to accumulate in beeswax; thus, careless practices might pose risks to colony development in commercial beekeeping and native populations. This laboratory study can serve as an early warning, and further studies are required to understand the real residual level of flumethrin in bees and the risks of flumethrin in field condition.


Assuntos
Abelhas/fisiologia , Inseticidas/toxicidade , Piretrinas/toxicidade , Animais , Criação de Abelhas , Dose Letal Mediana , Testes de Toxicidade Crônica
14.
Environ Sci Pollut Res Int ; 27(7): 6971-6980, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31879892

RESUMO

Potential synergistic toxicity of pesticide mixtures has increasingly become a concern to the health of crop pollinators. The toxicities of individual and mixture of chlorpyrifos (CHL), acephate (ACE), or tetraconazole (TET) with nine pyrethroid insecticides to honey bees (Apis mellifera L.) were evaluated to reveal any aggregated interaction between pesticides. Results from feeding toxicity tests of individual pesticides indicated that organophosphate insecticides CHL and ACE had higher toxicities to honey bees compared to nine pyrethroids. Moreover, different pyrethroids exhibited considerable variation in toxicity with LC50 values ranging from 10.05 (8.60-11.69) to 1125 (922.4-1442) mg a.i. L-1 after exposure for 7 days. Among the 12 examined pesticides, a relatively low toxicity to A. mellifera was detected from the fungicide TET. All the binary mixtures of ACE or TET in combination with pyrethroids exhibited synergistic effects. However, TET in combination with pyrethroids showed greater synergistic toxicity to A. mellifera than ACE in combination with pyrethroids. Approximately 50% binary mixtures of CHL in combination with pyrethroids also showed synergistic responses in honey bees. In particular, CHL, ACE, or TET in combination with either lambda-cyhalothrin (LCY) or bifenthrin (BIF) showed the strongest synergy in A. mellifera, followed by CHL, ACE, or TET in combination with either zeta-cypermethrin (ZCY) or cypermethrin (CYP). The findings indicated that the co-exposure of various pesticides in natural settings might lead to severe injury to crop pollinators. Therefore, pesticide mixtures should be applied carefully in order to minimize negative effects on honey bees while maintaining effective management against crop pests.


Assuntos
Abelhas/fisiologia , Inseticidas/toxicidade , Piretrinas/toxicidade , Animais , Clorobenzenos/toxicidade , Clorpirifos/toxicidade , Sinergismo Farmacológico , Fungicidas Industriais/toxicidade , Compostos Organotiofosforados/toxicidade , Fosforamidas/toxicidade , Triazóis/toxicidade
15.
J Agric Food Chem ; 67(48): 13221-13227, 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31682121

RESUMO

Apple flowers of most varieties require pollinator-mediated cross-pollination. However, little is known about the cues used by pollinators to find the flowers. We used bioassays to investigate the importance of visual and olfactory cues for the attraction of honeybee pollinators to apple flowers. Chemical-analytical and electrophysiological approaches were used to determine floral scents and investigate antennal responses of honeybees to scents from flowering twigs. Bioassays showed that visual and olfactory cues were equally important for the attraction of honeybees to apple flowers. Floral scents were dominated by aromatic components, mainly benzyl alcohol, and the antennae of honeybees responded to a large number of components, among them to benzyl alcohol, linalool, and indole. Our study aims to better understand how this important fruit crop communicates with its main pollinators. This knowledge might be used to improve the attractiveness of apple flowers to pollinators to optimize fruit sets.


Assuntos
Abelhas/fisiologia , Malus/química , Compostos Orgânicos Voláteis/química , Animais , Flores/química , Flores/parasitologia , Cromatografia Gasosa-Espectrometria de Massas , Malus/parasitologia , Odorantes/análise , Polinização , Olfato
16.
An Acad Bras Cienc ; 91(4): e20190360, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31778461

RESUMO

An entomopalynological study to assess pollen use by wild bees was performed in an urban environment with riparian native forest in the Chaco region of Argentina. A combined method for sampling pollen loads and garbage pellets at nest entrances in four stingless bees with different entrance size and forager traffic was here successfully used. Sampling was carried out in a short period of time (late winter) and located within a distance of 50 m. Pollen analysis using acetolysis showed that most identified pollen types (31) were from native species, 12 from ornamental exotic species, 5 included native and ornamental exotic species and 18 of uncertain status. A much broader pollen spectrum was present in garbage pellets (62 types) than loads (14 types). A few resources from previous blooming (late spring-summer) were identified in garbage pellets, which were mainly composed of current flowerings. From the 66 pollen types found in all samples, many (18) remained unidentified due to the complex nature of the vegetation surrounding the nests and the generalist behaviour of these bees. The versatile foraging behaviour on spontaneous (mostly native) and cultivated (mostly ornamental exotic) pollen resources is an important issue for the conservation and rearing of stingless bee colonies in urban habitats where native flora is preserved, particularly the riparians, where a high richness of blooming plants is available.


Assuntos
Abelhas/fisiologia , Flores , Pólen , Animais , Argentina , Abelhas/classificação , Florestas , Resíduos de Alimentos , Estações do Ano
17.
Nat Commun ; 10(1): 4802, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31641114

RESUMO

Microbes can establish mutualistic interactions with plants and insects. Here we track the movement of an endophytic strain of Streptomyces bacteria throughout a managed strawberry ecosystem. We show that a Streptomyces isolate found in the rhizosphere and on flowers protects both the plant and pollinating honeybees from pathogens (phytopathogenic fungus Botrytis cinerea and pathogenic bacteria, respectively). The pollinators can transfer the Streptomyces bacteria among flowers and plants, and Streptomyces can move into the plant vascular bundle from the flowers and from the rhizosphere. Our results present a tripartite mutualism between Streptomyces, plant and pollinator partners.


Assuntos
Abelhas/fisiologia , Fragaria/fisiologia , Streptomyces/fisiologia , Animais , Botrytis/patogenicidade , Flores , Fragaria/microbiologia , Doenças das Plantas/microbiologia , Pólen , Polinização , RNA Ribossômico 16S , República da Coreia , Esporos Fúngicos , Streptomyces/genética , Simbiose
18.
J Agric Food Chem ; 67(43): 12105-12116, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31600056

RESUMO

Sublethal exposure to neonicotinoids affects honey bee olfaction, but few studies have investigated the sublethal effects of the enantioselective neonicotinoid dinotefuran on honey bee olfaction. This study assessed the sublethal olfactory toxicity of dinotefuran enantiomers to honey bees. Compared to R-dinotefuran, S-dinotefuran had higher acute oral toxicity, sucrose sensitivity effects, octopamine concentrations, lower learning ability, and memory effects on honey bees. High-throughput circular RNA sequencing of the honey bee brain revealed that R-dinotefuran caused more gene regulatory changes than S-dinotefuran. Gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses demonstrated that the SERCA, Kca, and Maxik genes may be related to the enantioselective effects of dinotefuran isomers on honey bee olfaction. These results indicated that the current ecotoxicological safety knowledge about chiral dinotefuran effects on honey bees should be amended.


Assuntos
Abelhas/efeitos dos fármacos , Guanidinas/toxicidade , Inseticidas/química , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Animais , Abelhas/fisiologia , Guanidinas/química , Neonicotinoides/química , Nitrocompostos/química , Olfato/efeitos dos fármacos , Estereoisomerismo
19.
Ecotoxicology ; 28(9): 1056-1062, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31512041

RESUMO

While the ecological effects of pesticides have been well studied in honeybees, it is unclear to what extent other anthropogenic contaminants such as air pollution may also negatively affect bee cognition and behaviour. To answer this question, we assessed the impacts of acute exposure to four ecologically relevant concentrations of a common urban air pollutant-diesel generated air pollution on honeybee odour learning and memory using a conditioned proboscis extension response assay. The proportion of bees that successfully learnt odours following direct air pollution exposure was significantly lower in bees exposed to low, medium and high air pollutant concentrations, than in bees exposed to current ambient levels. Furthermore, short- and long-term odour memory was significantly impaired in bees exposed to low medium and high air pollutant concentrations than in bees exposed to current ambient levels. These results demonstrate a clear and direct cognitive cost of air pollution. Given learning and memory play significant roles in foraging, we suggest air pollution will have increasing negative impacts on the ecosystem services bees provide and may add to the current threats such as pesticides, mites and disease affecting colony fitness.


Assuntos
Poluição do Ar/efeitos adversos , Abelhas/efeitos dos fármacos , Percepção Olfatória/efeitos dos fármacos , Animais , Abelhas/fisiologia , Cidades , Aprendizagem/efeitos dos fármacos , Memória/efeitos dos fármacos
20.
J Insect Sci ; 19(5)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31557288

RESUMO

Flowers may become inoculated with pathogens that can infect bees and other critical pollinators, but the mechanisms of inoculation remain unclear. During foraging, bees may regurgitate or defecate directly onto flower parts, which could inoculate flowers with pollinator pathogens and lead to subsequent disease transmission to floral visitors. We tested if captive eastern bumble bees (Bombus impatiens) (Cresson) (Hymenoptera: Apidae) defecate on floral surfaces during foraging and if flower shape played a role in the probability of defecation and the quantity of feces deposited on floral surfaces. Captive Bombus impatiens were fed a solution of fluorescent dye and sucrose, then allowed to forage freely on flowers of a variety of shapes in a flight cage. Flowers were then examined under ultraviolet light for fluorescing fecal matter. We found that bumble bees did defecate on floral surfaces during foraging and that composite flowers with a large area of disk flowers were the most likely to have feces on them. Our results point to defecation by bumble bees during foraging as a potential mechanism for inoculation of flowers with pollinator pathogens and suggest that flower shape could play a significant role in inoculation.


Assuntos
Abelhas/fisiologia , Defecação , Flores/anatomia & histologia , Animais , Comportamento Excretor Animal , Magnoliopsida , Polinização
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