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1.
J Exp Biol ; 224(14)2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34263905

RESUMO

Resting metabolic rate (RMR) is a fundamental physiological measure linked to numerous aspects of organismal function, including lifespan. Although dietary restriction in insects during larval growth/development affects adult RMR, the impact of the nutritional composition of larval diets (i.e. diet quality) on adult RMR has not been studied. Using in vitro rearing to control larval diet quality, we determined the effect of dietary protein and carbohydrate on honeybee survival to adulthood, time to eclosion, body mass/size and adult RMR. High carbohydrate larval diets increased survival to adulthood and time to eclosion compared with both low carbohydrate and high protein diets. Upon emergence, bees reared on the high protein diet were smaller and lighter than those reared on other diets, whilst those raised on the high carbohydrate diet varied more in body mass. Newly emerged adult bees reared on the high carbohydrate diet showed a significantly steeper increase in allometric scaling of RMR compared with those reared on other diets. This suggests that the nutritional composition of larval diets influences survival to adulthood, time to eclosion and the allometric scaling of RMR. Given that agricultural intensification and increasing urbanisation have led to a decrease in both forage availability and dietary diversity for bees, our results are critical to improving understanding of the impacts of poor developmental nutrition on bee growth/development and physiology.


Assuntos
Dieta , Proteínas Alimentares , Animais , Abelhas , Tamanho Corporal , Larva , Estado Nutricional
2.
Naturwissenschaften ; 105(1-2): 8, 2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29294192

RESUMO

The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees' responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees' preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects.


Assuntos
Abelhas/fisiologia , Comportamento de Escolha/fisiologia , Cor , Flores/fisiologia , Animais , Aprendizagem , Especificidade da Espécie , Clima Tropical , Raios Ultravioleta
3.
Environ Sci Technol ; 52(16): 9391-9402, 2018 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-29952204

RESUMO

Concerns regarding the impact of neonicotinoid exposure on bee populations recently led to an EU-wide moratorium on the use of certain neonicotinoids on flowering crops. Currently, evidence regarding the impact, if any, the moratorium has had on bees' exposure is limited. We sampled pollen and nectar from bumblebee colonies in rural and peri-urban habitats in three U.K. regions: Stirlingshire, Hertfordshire, and Sussex. Colonies were sampled over three years: prior to the ban (2013), during the initial implementation when some seed-treated winter-sown oilseed rape was still grown (2014), and following the ban (2015). To compare species-level differences, in 2014 only, honeybee colonies in rural habitats were also sampled. Over half of all samples were found to be contaminated ( n = 408), with thiamethoxam being the compound detected at the highest concentrations in honeybee- (up to 2.29 ng/g in nectar in 2014, median ≤ 0.1 ng/g, n = 79) and bumblebee-collected pollen and nectar (up to 38.77 ng/g in pollen in 2013, median ≤ 0.12 ng/g, n = 76). Honeybees were exposed to higher concentrations of neonicotinoids than bumblebees in 2014. While neonicotinoid exposure for rural bumblebees declined post-ban (2015), suggesting a positive impact of the moratorium, the risk of neonicotinoid exposure for bumblebees in peri-urban habitats remained largely the same between 2013 and 2015.


Assuntos
Inseticidas , Néctar de Plantas , Animais , Abelhas , Produtos Agrícolas , Neonicotinoides , Pólen , Tiametoxam
4.
Sci Prog ; 99(3): 312-326, 2016 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28742491

RESUMO

Bee declines have received much attention of late, but there is considerable debate and confusion as to the extent, significance and causes of declines. In part, this reflects conflation of data for domestic honeybees, numbers of which are largely driven by economic factors, with those for wild bees, many of which have undergone marked range contractions but for the majority of which we have no good data on population size. There is no doubt that bees are subject to numerous pressures in the modern world. The abundance and diversity of flowers has declined along with availability of suitable nest sites, bees are chronically exposed to cocktails of agrochemicals, and they are simultaneously exposed to novel parasites and pathogens accidentally spread by humans. Climate change is likely to exacerbate these problems in the future, particularly for cool- climate specialists such as bumblebees. Stressors do not act in isolation; for example pesticide exposure can impair both detoxification mechanisms and immune responses, rendering bees more susceptible to parasites. It seems certain that chronic exposure to multiple, interacting stressors is driving honeybee colony losses and declines of wild pollinators. Bees have a high profile and so their travails attract attention, but these same stressors undoubtedly bear upon other wild organisms, many of which are not monitored and have few champions. Those wild insects for which we do have population data (notably butterflies and moths) are overwhelmingly also in decline. We argue that bee declines are indicators of pervasive and ongoing environmental damage that is likely to impact broadly on biodiversity and the ecosystem services it provides.

5.
Environ Sci Technol ; 49(21): 12731-40, 2015 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-26439915

RESUMO

In recent years, an intense debate about the environmental risks posed by neonicotinoids, a group of widely used, neurotoxic insecticides, has been joined. When these systemic compounds are applied to seeds, low concentrations are subsequently found in the nectar and pollen of the crop, which are then collected and consumed by bees. Here we demonstrate that the current focus on exposure to pesticides via the crop overlooks an important factor: throughout spring and summer, mixtures of neonicotinoids are also found in the pollen and nectar of wildflowers growing in arable field margins, at concentrations that are sometimes even higher than those found in the crop. Indeed, the large majority (97%) of neonicotinoids brought back in pollen to honey bee hives in arable landscapes was from wildflowers, not crops. Both previous and ongoing field studies have been based on the premise that exposure to neonicotinoids would occur only during the blooming period of flowering crops and that it may be diluted by bees also foraging on untreated wildflowers. Here, we show that exposure is likely to be higher and more prolonged than currently recognized because of widespread contamination of wild plants growing near treated crops.


Assuntos
Anabasina/toxicidade , Abelhas/metabolismo , Exposição Ambiental/análise , Flores/química , Animais , Brassica rapa/química , Produtos Agrícolas/química , Hordeum/química , Inseticidas/análise , Néctar de Plantas/química , Pólen/química , Sementes/química , Solo/química , Triticum/química
6.
J Pediatr Psychol ; 40(6): 602-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25613917

RESUMO

OBJECTIVE: No studies have examined psychological functioning among youth with spina bifida (SB) living in a developing country where access to mental health resources is often scarce. This study compared self-reported psychological functioning between youth with SB living in Colombia, South America, and a demographically matched comparison group of healthy Colombian children. METHODS: 22 children with SB and 22 comparison children completed assessments of depression and anxiety. Most (68.81%) participants were male, and the sample had a mean age of 13.25 years (SD = 2.65 years). RESULTS: Results revealed that children with SB reported greater total symptoms of depression (p < .05), but fewer worry-related symptoms of anxiety (p < .05). In addition, mean total scores for both depression and anxiety were in the nonclinical range for youth with SB. CONCLUSIONS: These findings highlight the need for targeted mental health (i.e., depression) services for poor children with SB living in Colombia.


Assuntos
Transtornos de Ansiedade/epidemiologia , Transtornos de Ansiedade/psicologia , Transtorno Depressivo/epidemiologia , Transtorno Depressivo/psicologia , Disrafismo Espinal/epidemiologia , Disrafismo Espinal/psicologia , Adolescente , Criança , Colômbia/epidemiologia , Depressão/psicologia , Países em Desenvolvimento , Feminino , Humanos , Masculino , Qualidade de Vida/psicologia , América do Sul , Inquéritos e Questionários
7.
Phys Occup Ther Pediatr ; 35(1): 1-12, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24712841

RESUMO

AIMS: This exploratory study investigated whether children with attention-deficit/hyperactivity disorder (ADHD) are at greater risk than children without ADHD for problems with sensory processing and if certain sensory systems are more closely associated with the core symptoms of ADHD, specifically inattention and hyperactivity/impulsivity. METHODS: The sample included 20 children with ADHD and 27 children without ADHD, ages 5 to 10 years. Assessments included the Sensory Processing Measure-Home Form and the Conners 3rd edition-Parent Short Form. RESULTS: After controlling for age, children with ADHD exhibited more sensory processing problems on all scales of the Sensory Processing Measure with small to medium effect sizes observed (η(2) = .27 to .61). For children with ADHD, the Social Participation (r = .50) and Planning and Ideas (r = .73) subtests of the Sensory Processing Measure were significantly associated with hyperactivity/impulsivity, but not with inattention on the subtests of the Conners Parent Short Form. CONCLUSION: The results suggest the importance of assessing sensory processing issues in children with ADHD to guide in the intervention process.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtornos de Sensação/diagnóstico , Transtornos de Sensação/fisiopatologia , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Inquéritos e Questionários
8.
J Cross Cult Gerontol ; 30(4): 393-408, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26290365

RESUMO

Existing published studies about health-related quality of life (HRQOL) in caregivers of dementia patients living in Latin American countries are very limited. However, cultural aspects, personal values, and social structure may affect the way caregivers experience their role in different societies. The current study investigated the relationship between HRQOL and psychological factors using a cross-sectional design. The sample consisted of 102 informal caregivers of patients with dementia from Bogotá, Colombia, South America. Measures included the Patient Health Questionnaire (PHQ-9) for depression, the Satisfaction with Life Scale (SWLS), the Zarit Burden Interview, and the Short Health Questionnaire (SF36) for HRQOL. Canonical correlations revealed that there was a significant relationship between caregivers' mental health and HRQOL, such that caregivers with better satisfaction with life and less symptoms of depression had more vitality and better general health. There is a strong relationship between mental health and health-related quality of life in Colombian caregivers of dementia patients living in their country of origin. Specific aspects of mental health, including satisfaction with life and depression, need to be addressed in order to improve caregivers' quality of life. Given that mental health care resources may be scarce in Latin American countries, culturally appropriate interventions should focus on preventing/treating depression and promote life satisfaction, as a way to improve their quality of life.


Assuntos
Cuidadores/psicologia , Demência/enfermagem , Indicadores Básicos de Saúde , Satisfação Pessoal , Qualidade de Vida/psicologia , Adulto , Idoso , Colômbia , Estudos Transversais , Demência/psicologia , Depressão/psicologia , Feminino , Humanos , Masculino , Saúde Mental , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Fatores Socioeconômicos , Inquéritos e Questionários
9.
J Exp Biol ; 217(Pt 15): 2783-8, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24855678

RESUMO

In contrast to the wealth of knowledge concerning sucrose-rewarded learning, the question of whether bees learn when they collect pollen from flowers has been little addressed. The nutritional value of pollen varies considerably between species, and it may be that bees learn the features of flowers that produce pollen best suited to the dietary requirements of their larvae. It is still unknown, however, whether a non-ingestive reward pathway for pollen learning exists, and how foraging bees sense differences between pollen types. Here we adopt a novel experimental approach testing the learning ability of bees with pollen rewards. Bumblebees were reared under controlled laboratory conditions. To establish which pollen rewards are distinguishable, individual bees were given the choice of collecting two types of pollen, diluted to varying degrees with indigestible α-cellulose. Bees preferentially collected a particular pollen type, but this was not always the most concentrated sample. Preferences were influenced by the degree of similarity between samples and also by the period of exposure, with bees more readily collecting samples of lower pollen concentration after five trials. When trained differentially, bees were able to associate an initially less-preferred contextual colour with the more concentrated sample, whilst their pollen preferences did not change. Successful learning of contextual cues seems to maintain pollen foraging preferences over repeated exposures, suggesting that fast learning of floral cues may preclude continuous sampling and evaluation of alternative reward sources, leading to constancy in pollen foraging.


Assuntos
Abelhas/fisiologia , Cor , Aprendizagem , Pólen , Animais , Comportamento de Escolha , Sinais (Psicologia) , Comportamento Alimentar , Recompensa
10.
PeerJ ; 12: e17135, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38529302

RESUMO

Climate change is currently considered one of the major threats to biodiversity and is associated with an increase in the frequency and intensity of extreme weather events, such as heatwaves. Heatwaves create acutely stressful conditions that may lead to disruption in the performance and survival of ecologically and economically important organisms, such as insect pollinators. In this study, we investigated the impact of simulated heatwaves on the performance of queenless microcolonies of Bombus terrestris audax under laboratory conditions. Our results indicate that heatwaves can have significant impacts on bumblebee performance. However, contrary to our expectations, exposure to heatwaves did not affect survival. Exposure to a mild 5-day heatwave (30-32 °C) resulted in increased offspring production compared to those exposed to an extreme heatwave (34-36 °C) and to the control group (24 °C). We also found that brood-care behaviours were impacted by the magnitude of the heatwave. Wing fanning occurred occasionally at temperatures of 30-32 °C, whereas at 34-36 °C the proportion of workers engaged in this thermoregulatory behaviour increased significantly. Our results provide insights into the effects of heatwaves on bumblebee colony performance and underscore the use of microcolonies as a valuable tool for studying the effects of extreme weather events. Future research, especially field-based studies replicating natural foraging conditions, is crucial to complement laboratory-based studies to comprehend how heatwaves compromise the performance of pollinators. Such studies may potentially help to identify those species more resilient to climate change, as well as those that are most vulnerable.


Assuntos
Mudança Climática , Dispositivos Aéreos não Tripulados , Animais , Abelhas , Biodiversidade , Insetos , Temperatura
11.
Brain Inj ; 26(6): 875-81, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22583178

RESUMO

OBJECTIVE: To examine the effect of self-generation on learning and memory in Spanish-speaking individuals with traumatic brain injury (TBI). METHOD: Thirty Spanish-speaking individuals with moderate-to-severe TBI and 31 healthy controls were recruited to read 32 individual sentences and required to remember the last word in each sentence. Target words were presented both in a self-generated and provided condition for each participant. Recall and recognition of the words were examined immediately, after 30 minutes and after 1 week. RESULTS: Findings indicated that both healthy controls and individuals with TBI showed significantly better recall and recognition for words in the generated condition than words that had been provided to them at immediate, 30-minute and 1-week time intervals. CONCLUSION: The self-generation technique effectively improves learning and memory in Spanish-speaking individuals with TBI. Results should encourage researchers and clinicians to use the principles of cognitive psychology to adapt (as opposed to simply translate) cognitive rehabilitation protocols for use in Spanish-speaking populations with neurological conditions.


Assuntos
Aprendizagem por Associação , Lesões Encefálicas/psicologia , Lesões Encefálicas/reabilitação , Transtornos Cognitivos/psicologia , Transtornos Cognitivos/reabilitação , Rememoração Mental , Retenção Psicológica , Adolescente , Adulto , Idoso , Lesões Encefálicas/complicações , Lesões Encefálicas/epidemiologia , Estudos de Casos e Controles , Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/etiologia , Colômbia/epidemiologia , Feminino , Humanos , Escala de Gravidade do Ferimento , Idioma , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Fatores de Tempo , Adulto Jovem
12.
Science ; 375(6584): 970-972, 2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-35239360
13.
Anim Cogn ; 14(1): 21-34, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20652343

RESUMO

Two experiments examined whether pigeons discriminate polymorphous categories on the basis of a single highly predictive feature or overall similarity. In the first experiment, pigeons were trained to discriminate between categories of photographs of complex real objects. Within these pictures, single features had been manipulated to produce a highly salient texture cue. Either the picture or the texture provided a reliable cue for discrimination during training, but in probe tests, the picture and texture cues were put into conflict. Some pigeons showed a significant tendency to discriminate on the basis of the picture cue (overall similarity or family resemblance), whereas others appeared to rely on the manipulated texture cue. The second experiment used artificial polymorphous categories in which one dimension of the stimulus provided a completely reliable cue to category membership, whereas three other dimensions provided cues that were individually unreliable but collectively provided a completely reliable basis for discrimination. Most pigeons came under the control of the reliable cue rather than the unreliable cues. A minority, however, came under the control of single dimensions from the unreliable set. We conclude that cue salience can be more important than cue reliability in determining what features will control behavior when multiple cues are available.


Assuntos
Aprendizagem por Discriminação , Reconhecimento Visual de Modelos , Animais , Columbidae , Sinais (Psicologia)
15.
Arch Phys Med Rehabil ; 91(10): 1495-504, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20875505

RESUMO

OBJECTIVE: To develop a prediction rule for acutely identifying patients at risk for extended rehabilitation length of stay (LOS) after traumatic brain injury (TBI) by using demographic and injury characteristics. DESIGN: Retrospective cohort study. SETTING: Traumatic Brain Injury Model Systems. PARTICIPANTS: Sample of TBI survivors (N=7284) with injuries occurring between 1999 and 2009. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Extended rehabilitation LOS defined as 67 days or longer. RESULTS: A multivariable model was built containing FIM motor and cognitive scores at admission, preinjury level of education, cause of injury, punctate/petechial hemorrhage, acute-care LOS, and primary payor source. The model had good calibration, excellent discrimination (area under the receiver operating characteristic curve = .875), and validated well. Based on this model, a formula for determining the probability of extended rehabilitation LOS and a prediction rule that classifies patients with predicted probabilities greater than 4.9% as at risk for extended rehabilitation LOS were developed. CONCLUSIONS: The current predictor model for TBI survivors who require extended inpatient rehabilitation may allow for enhanced rehabilitation team planning, improved patient and family education, and better use of health care resources. Cross-validation of this model with other TBI populations is recommended.


Assuntos
Lesões Encefálicas/reabilitação , Cobertura do Seguro/estatística & dados numéricos , Seguro Saúde/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Modelos Estatísticos , Adulto , Estudos de Coortes , Escolaridade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recuperação de Função Fisiológica , Estudos Retrospectivos , Índices de Gravidade do Trauma
16.
Brain Inj ; 24(7-8): 1017-26, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20545455

RESUMO

OBJECTIVE: The aim of the present study was to determine the most and least important family needs in a group of family caregivers of individuals with TBI from Cali, Colombia, and to examine which of those needs were more likely to be met and unmet. DESIGN: Cross-sectional descriptive study. SETTING: Valle University Hospital in Cali, Colombia. PARTICIPANTS: Twenty-nine family caregivers of individuals with traumatic brain injury. OUTCOME MEASURE: The Family Needs Questionnaire, a 40-item questionnaire divided into six sub-scales. RESULTS: Health Information, Community Support Network and Professional Support Network sub-scales were the most important needs reported by this group of Colombian TBI family caregivers. The most frequently met needs in the present study fell within Health Information, Involvement with Care and Instrumental Support sub-scales and the most frequently unmet needs fell within the Emotional Support, Instrumental Support and Professional Support sub-scales. CONCLUSIONS: Family needs in caregivers of individuals with TBI from Colombia are similar, but more likely to be unmet, than those reported in previous studies. Interventions designed to meet family caregivers' needs in these areas should be implemented in Colombia.


Assuntos
Lesões Encefálicas/enfermagem , Cuidadores/psicologia , Família/psicologia , Avaliação das Necessidades , Adulto , Lesões Encefálicas/reabilitação , Colômbia , Estudos Transversais , Feminino , Necessidades e Demandas de Serviços de Saúde , Humanos , Masculino , Apoio Social , Inquéritos e Questionários
17.
Issues Ment Health Nurs ; 30(8): 474-81, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19591020

RESUMO

A number of international studies have highlighted family caregivers' (FCGs') dissatisfaction with their relationship with mental health professionals (MHPs) when providing care for mentally ill family members. However, few studies have explored the mental health professionals' perspective of this relationship. This study explored both FCGs' and MHPs' perspectives. Semi-structured interviews were conducted with seven FCGs and seven MHPs from two different geographical areas of New Zealand. Thematic analysis of these interviews revealed four distinct MHP themes and five FCG themes. The themes illuminate incongruence between MHPs' intentions to form a positive working relationship with families and the FCGs' mainly negative experiences of this relationship.


Assuntos
Atitude do Pessoal de Saúde , Atitude Frente a Saúde , Família/psicologia , Pessoal de Saúde/psicologia , Transtornos Mentais/psicologia , Relações Profissional-Família , Adulto , Cuidadores/educação , Cuidadores/psicologia , Enfermagem em Saúde Comunitária/educação , Enfermagem em Saúde Comunitária/organização & administração , Comportamento Cooperativo , Desinstitucionalização/tendências , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde/educação , Humanos , Masculino , Transtornos Mentais/prevenção & controle , Pessoa de Meia-Idade , Nova Zelândia , Pesquisa Metodológica em Enfermagem , Enfermagem Psiquiátrica/educação , Enfermagem Psiquiátrica/organização & administração , Pesquisa Qualitativa , Serviço Social em Psiquiatria/educação , Serviço Social em Psiquiatria/organização & administração , Inquéritos e Questionários
18.
PeerJ ; 5: e3417, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28649467

RESUMO

There is widespread concern regarding the effects of agro-chemical exposure on bee health, of which neonicotinoids, systemic insecticides detected in the pollen and nectar of both crops and wildflowers, have been the most strongly debated. The majority of studies examining the effect of neonicotinoids on bees have focussed on social species, namely honey bees and bumble bees. However, most bee species are solitary, their life histories differing considerably from these social species, and thus it is possible that their susceptibility to pesticides may be quite different. Studies that have included solitary bees have produced mixed results regarding the impact of neonicotinoid exposure on survival and reproductive success. While the majority of studies have focused on the effects of adult exposure, bees are also likely to be exposed as larvae via the consumption of contaminated pollen. Here we examined the effect of exposure of Osmia bicornis larvae to a range of field-realistic concentrations (0-10 ppb) of the neonicotinoid clothianidin, observing no effect on larval development time, overwintering survival or adult weight. Flow-through respirometry was used to test for latent effects of larval exposure on adult physiological function. We observed differences between male and female bees in the propensity to engage in discontinuous gas exchange; however, no effect of larval clothianidin exposure was observed. Our results suggest that previously reported adverse effects of neonicotinoids on O. bicornis are most likely mediated by impacts on adults.

19.
PeerJ ; 4: e1808, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27014515

RESUMO

In recent years, many pollinators have declined in abundance and diversity worldwide, presenting a potential threat to agricultural productivity, biodiversity and the functioning of natural ecosystems. One of the most debated factors proposed to be contributing to pollinator declines is exposure to pesticides, particularly neonicotinoids, a widely used class of systemic insecticide. Also, newly emerging parasites and diseases, thought to be spread via contact with managed honeybees, may pose threats to other pollinators such as bumblebees. Compared to honeybees, bumblebees could be particularly vulnerable to the effects of stressors due to their smaller and more short-lived colonies. Here, we studied the effect of field-realistic, chronic clothianidin exposure and inoculation with the parasite Nosema ceranae on survival, fecundity, sugar water collection and learning using queenless Bombus terrestris audax microcolonies in the laboratory. Chronic exposure to 1 ppb clothianidin had no significant effects on the traits studied. Interestingly, pesticide exposure in combination with additional stress caused by harnessing bees for Proboscis Extension Response (PER) learning assays, led to an increase in mortality. In contrast to previous findings, the bees did not become infected by N. ceranae after experimental inoculation with the parasite spores, suggesting variability in host resistance or parasite virulence. However, this treatment induced a slight, short-term reduction in sugar water collection, potentially through stimulation of the immune system of the bees. Our results suggest that chronic exposure to 1 ppb clothianidin does not have adverse effects on bumblebee fecundity or learning ability.

20.
Environ Int ; 88: 169-178, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26760714

RESUMO

There is considerable and ongoing debate as to the harm inflicted on bees by exposure to agricultural pesticides. In part, the lack of consensus reflects a shortage of information on field-realistic levels of exposure. Here, we quantify concentrations of neonicotinoid insecticides and fungicides in the pollen of oilseed rape, and in pollen of wildflowers growing near arable fields. We then compare this to concentrations of these pesticides found in pollen collected by honey bees and in pollen and adult bees sampled from bumble bee colonies placed on arable farms. We also compared this with levels found in bumble bee colonies placed in urban areas. Pollen of oilseed rape was heavily contaminated with a broad range of pesticides, as was the pollen of wildflowers growing nearby. Consequently, pollen collected by both bee species also contained a wide range of pesticides, notably including the fungicides carbendazim, boscalid, flusilazole, metconazole, tebuconazole and trifloxystrobin and the neonicotinoids thiamethoxam, thiacloprid and imidacloprid. In bumble bees, the fungicides carbendazim, boscalid, tebuconazole, flusilazole and metconazole were present at concentrations up to 73nanogram/gram (ng/g). It is notable that pollen collected by bumble bees in rural areas contained high levels of the neonicotinoids thiamethoxam (mean 18ng/g) and thiacloprid (mean 2.9ng/g), along with a range of fungicides, some of which are known to act synergistically with neonicotinoids. Pesticide exposure of bumble bee colonies in urban areas was much lower than in rural areas. Understanding the effects of simultaneous exposure of bees to complex mixtures of pesticides remains a major challenge.


Assuntos
Fungicidas Industriais/análise , Inseticidas/análise , Magnoliopsida/química , Pólen/química , Animais , Abelhas/química , Brassica napus/química , Inglaterra , Monitoramento Ambiental
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