Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Collabra Psychol ; 10(1): 92949, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38463460

RESUMO

Habits pose a fundamental puzzle for those aiming to understand human behavior. They pervade our everyday lives and dominate some forms of psychopathology but are extremely hard to elicit in the lab. In this Registered Report, we developed novel experimental paradigms grounded in computational models, which suggest that habit strength should be proportional to the frequency of behavior and, in contrast to previous research, independent of value. Specifically, we manipulated how often participants performed responses in two tasks varying action repetition without, or separately from, variations in value. Moreover, we asked how this frequency-based habitization related to value-based operationalizations of habit and self-reported propensities for habitual behavior in real life. We find that choice frequency during training increases habit strength at test and that this form of habit shows little relation to value-based operationalizations of habit. Our findings empirically ground a novel perspective on the constituents of habits and suggest that habits may arise in the absence of external reinforcement. We further find no evidence for an overlap between different experimental approaches to measuring habits and no associations with self-reported real-life habits. Thus, our findings call for a rigorous reassessment of our understanding and measurement of human habitual behavior in the lab.

2.
J Pers ; 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37990332

RESUMO

OBJECTIVE: Which traits best describe individuals who are recognized as exemplary in different domains? And can self-rated positively valued personality traits distinguish such individuals from the general population? BACKGROUND: The study of exemplary individuals' personality traits traditionally focused on general and broad traits. Using character strengths, which are narrower and designed to describe desirable behavior, could provide new insights. METHOD: In this study, we examined 204 outstanding individuals-exemplars who received or were nominated for a public award recognizing their exemplary behavior (e.g., a Carnegie Rescuers Award; n = 119), individuals holding a patent (n = 62), and individuals living in a religious order (n = 23). We compared these exemplars to comparison samples matched based on demographic variables. All participants completed self-report questionnaires assessing character strengths and well-being (e.g., satisfaction with life). RESULTS: Results showed that the three groups of exemplars differed meaningfully in their character strengths and well-being from the matched comparison groups. Compared with matched counterparts, moral exemplars scored higher on the strengths related to the virtues of courage, humanity, and justice as well as the character strength of humility, creative exemplars scored higher on the character strengths of creativity and honesty, and religious exemplars scored higher on gratitude and spirituality. CONCLUSION: Overall, our findings suggest that character strengths are a useful framework for studying exemplary behavior.

3.
Psychol Sci ; 34(10): 1163-1172, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37732970

RESUMO

There is robust evidence that people with higher incomes tend to have higher self-esteem, but little is known about how changes in income and self-esteem are related within individuals. Some theories predict that increased earnings lead to higher self-esteem, others that increased self-esteem leads to higher earnings, and still others that there should be no within-person associations between these variables. We tested these theories in 4-year longitudinal data from more than 4,000 adult participants from a Dutch representative sample. Results indicated significant between-person associations between income and self-esteem, consistent with prior research. Within-person effects suggested that increases in self-esteem are a function of previous increases in income more than the other way around. These links held when analyses controlled for employment status, and they generalized across gender, age, and educational background. Overall, the findings provide evidence for theories that consider self-esteem as both a source and a consequence of personal earnings.


Assuntos
Renda , Autoimagem , Adulto , Humanos , Emprego , Identidade de Gênero , Relações Interpessoais
4.
J Pers Assess ; 105(1): 34-47, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35298345

RESUMO

Character strengths are assessed in adults and adolescents using different measurements. However, a comparison of character strengths across age groups requires the equivalence of these measurements. The present study examined the comparability of the two questionnaires most frequently used in research: The VIA Inventory of Strengths (VIA-IS) for adults and the VIA Inventory of Strengths for Youth (VIA-Youth). A sample of N = 170 high-school students in the age of about 18 years and up to two informants (N = 164 mostly parents; N = 156 mostly friends and partners) completed both character strengths questionnaires and several well-being questionnaires. The psychometric characteristics and the correlations with well-being scales were examined once exclusively on the basis of self-rating and once on the basis of combined self- and informant-ratings. Substantial differences between the questionnaires were found in each of the criteria examined (e.g., identification of signature strengths, or largest associations with well-being). The results indicate that VIA-IS and VIA-Youth measure character strengths differently, so that a comparison across age groups may lead to biased conclusions. Therefore, differences in character strengths between adults and adolescents should not be exclusively interpreted in terms of differences on the trait level as these differences may be caused by nonequivalent questionnaires.


Assuntos
Caráter , Humanos , Adulto , Adolescente , Inquéritos e Questionários , Psicometria
5.
Insects ; 13(5)2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35621806

RESUMO

In response to the concerns of beekeepers on the decline of honey bee populations on lavender honey flow in the lavender fields of southeast France and the consequent decrease of honey production, our long-term survey (2009-2021) monitored the total weight gain collected by these colonies. This study shows the variations in the total weight gain according to regions, years, populations structure (bee number and quantity of capped brood) and Varroa load. Among these factors, years and regions support one third of the variations over this 13-year survey. At the beginning of the honey flow, capped brood is more important than the number of bees, whereas Varroa load severely limits the performance of the colonies. A threshold of 3 mites/100 bees seems to reflect the upper limit of the Varroa load below which the total weight gain is not affected. This survey provides useful information for the beekeepers to better prepare the colonies for this honey flow and allows them to compare their results obtained with our general description of the total weight gains by year.

6.
J Pers ; 90(6): 1057-1069, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35303763

RESUMO

OBJECTIVE: Research on the associations between cognitive and noncognitive personality traits has widely neglected character strengths, that means positively and morally valued personality traits that constitute good character. METHOD: The present study aimed to bridge this gap by studying the associations between character strengths and fluid intelligence using different operationalizations of character strengths (including self- and informant-reports) and fluid intelligence in children, adolescents, and adults. RESULTS: The results, based on four samples (N = 193/290/330/324), suggested that morally valued personality traits are independent of fluid intelligence, with the exception of love of learning, which showed small but robust positive relationships with fluid intelligence across all samples. CONCLUSIONS: Nonetheless, we argue for further research on the associations with other cognitive abilities and interactions between character strengths and intelligence when examining their relationships with external criteria.


Assuntos
Caráter , Inteligência , Adulto , Adolescente , Criança , Humanos , Aptidão , Aprendizagem , Cognição
7.
Pathogens ; 10(6)2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-34070934

RESUMO

The parasitic Varroa destructor is considered a major pathogenic threat to honey bees and to beekeeping. Without regular treatment against this mite, honey bee colonies can collapse within a 2-3-year period in temperate climates. Beyond this dramatic scenario, Varroa induces reductions in colony performance, which can have significant economic impacts for beekeepers. Unfortunately, until now, it has not been possible to predict the summer Varroa population size from its initial load in early spring. Here, we present models that use the Varroa load observed in the spring to predict the Varroa load one or three months later by using easily and quickly measurable data: phoretic Varroa load and capped brood cell numbers. Built on 1030 commercial colonies located in three regions in the south of France and sampled over a three-year period, these predictive models are tools designed to help professional beekeepers' decision making regarding treatments against Varroa. Using these models, beekeepers will either be able to evaluate the risks and benefits of treating against Varroa or to anticipate the reduction in colony performance due to the mite during the beekeeping season.

8.
J Intell ; 9(1)2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33494412

RESUMO

In order to investigate the nature of complex problem solving (CPS) within the nomological network of cognitive abilities, few studies have simultantiously considered working memory and intelligence, and results are inconsistent. The Brunswik symmetry principle was recently discussed as a possible explanation for the inconsistent findings because the operationalizations differed greatly between the studies. Following this assumption, 16 different combinations of operationalizations of working memory and fluid reasoning were examined in the present study (N=152). Based on structural equation modeling with single-indicator latent variables (i.e., corrected for measurement error), it was found that working memory incrementally explained CPS variance above and beyond fluid reasoning in only 2 of 16 conditions. However, according to the Brunswik symmetry principle, both conditions can be interpreted as an asymmetrical (unfair) comparison, in which working memory was artificially favored over fluid reasoning. We conclude that there is little evidence that working memory plays a unique role in solving complex problems independent of fluid reasoning. Furthermore, the impact of the Brunswik symmetry principle was clearly demonstrated as the explained variance in CPS varied between 4 and 31%, depending on which operationalizations of working memory and fluid reasoning were considered. We argue that future studies investigating the interplay of cognitive abilities will benefit if the Brunswik principle is taken into account.

9.
Insects ; 11(1)2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31948048

RESUMO

Methods for the evaluation and comparison of the structure of numerous honeybee colonies are needed for the development of applied and fundamental field research, as well as to evaluate how the structure and activity of honeybee colonies evolve over time. ColEval complements existing methods, as it uses an online reference image bank for (human) learning and training purposes. ColEval is based on the evaluation of the surface area percentage occupied by different components of a honeybee colony: adult worker bees, open and capped brood, honey, nectar, and pollen. This method is an essential tool for the description of the evolution in the size of honeybee colonies. The procedure makes allowances for tendencies between different observers and uses them to calculate accurate measurements of honeybee colony evaluation. ColEval thus allows for a posteriori comparison of under- or over-evaluation made by different observers working on the same project; it is thus possible to eliminate observer bias in the measurements and to conduct large surveys.

10.
Front Psychol ; 9: 626, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29867627

RESUMO

The original aim of complex problem solving (CPS) research was to bring the cognitive demands of complex real-life problems into the lab in order to investigate problem solving behavior and performance under controlled conditions. Up until now, the validity of psychometric intelligence constructs has been scrutinized with regard to its importance for CPS performance. At the same time, different CPS measurement approaches competing for the title of the best way to assess CPS have been developed. In the first part of the paper, we investigate the predictability of CPS performance on the basis of the Berlin Intelligence Structure Model and Cattell's investment theory as well as an elaborated knowledge taxonomy. In the first study, 137 students managed a simulated shirt factory (Tailorshop; i.e., a complex real life-oriented system) twice, while in the second study, 152 students completed a forestry scenario (FSYS; i.e., a complex artificial world system). The results indicate that reasoning - specifically numerical reasoning (Studies 1 and 2) and figural reasoning (Study 2) - are the only relevant predictors among the intelligence constructs. We discuss the results with reference to the Brunswik symmetry principle. Path models suggest that reasoning and prior knowledge influence problem solving performance in the Tailorshop scenario mainly indirectly. In addition, different types of system-specific knowledge independently contribute to predicting CPS performance. The results of Study 2 indicate that working memory capacity, assessed as an additional predictor, has no incremental validity beyond reasoning. We conclude that (1) cognitive abilities and prior knowledge are substantial predictors of CPS performance, and (2) in contrast to former and recent interpretations, there is insufficient evidence to consider CPS a unique ability construct. In the second part of the paper, we discuss our results in light of recent CPS research, which predominantly utilizes the minimally complex systems (MCS) measurement approach. We suggest ecologically valid microworlds as an indispensable tool for future CPS research and applications.

11.
J Intell ; 6(3)2018 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31162457

RESUMO

Personality and intelligence are defined as hierarchical constructs, ranging from broad g-factors to (domain-)specific constructs. The present study investigated whether different combinations of hierarchical levels lead to different personality-intelligence correlations. Based on the integrative data analysis approach, we combined a total of five data sets. The focus of the first study (N = 682) was an elaborated measurement of personality (NEO-PI-R), which was applied with a relatively short intelligence test (Intelligence Structure Test 2000 R). In the second study (N = 413), a comprehensive measurement of intelligence (Berlin Intelligence Structure test) was used with a shorter personality questionnaire (NEO-FFI). In line with the Brunswik symmetry principle, the findings emphasize that personality-intelligence correlations varied greatly across the hierarchical levels of constructs considered in the analysis. On average, Openness showed the largest relation with intelligence. We recommend for future studies to investigate personality-intelligence relations at more fine-grained levels based on elaborated measurements of both personality and intelligence.

12.
Sci Rep ; 7(1): 8556, 2017 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-28819220

RESUMO

The honey bee is threatened by biological agents and pesticides that can act in combination to induce synergistic effects on its physiology and lifespan. The synergistic effects of a parasite/pesticide combination have been demonstrated on workers and queens, but no studies have been performed on drones despite their essential contribution to colony sustainability by providing semen diversity and quality. The effects of the Nosema ceranae/fipronil combination on the life traits and physiology of mature drones were examined following exposure under semi-field conditions. The results showed that the microsporidia alone induced moderate and localized effects in the midgut, whereas fipronil alone induced moderate and generalized effects. The parasite/insecticide combination drastically affected both physiology and survival, exhibiting an important and significant generalized action that could jeopardize mating success. In terms of fertility, semen was strongly impacted regardless of stressor, suggesting that drone reproductive functions are very sensitive to stress factors. These findings suggest that drone health and fertility impairment might contribute to poorly mated queens, leading to the storage of poor quality semen and poor spermathecae diversity. Thus, the queens failures observed in recent years might result from the continuous exposure of drones to multiple environmental stressors.


Assuntos
Abelhas/microbiologia , Abelhas/fisiologia , Nosema/fisiologia , Pirazóis/farmacologia , Animais , Fertilidade/efeitos dos fármacos , Fertilidade/fisiologia , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/fisiologia , Interações Hospedeiro-Patógeno , Inseticidas/farmacologia , Masculino , Reprodução/efeitos dos fármacos , Reprodução/fisiologia
13.
Environ Pollut ; 229: 386-393, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28618362

RESUMO

Under laboratory conditions, the effects of thiamethoxam were investigated in larvae, pupae and emerging honey bees after exposure at larval stages with different concentrations in the food (0.00001 ng/µL, 0.001 ng/µL and 1.44 ng/µL). Thiamethoxam reduced the survival of larvae and pupae and consequently decreased the percentage of emerging honey bees. Thiamethoxam induced important physiological disturbances. It increased acetylcholinesterase (AChE) activity at all developmental stages and increased glutathione-S-transferase (GST) and carboxylesterase para (CaEp) activities at the pupal stages. For midgut alkaline phosphatase (ALP), no activity was detected in pupae stages, and no effect was observed in larvae and emerging bees. We assume that the effects of thiamethoxam on the survival, emergence and physiology of honey bees may affect the development of the colony. These results showed that attention should be paid to the exposure to pesticides during the developmental stages of the honey bee. This study represents the first investigation of the effects of thiamethoxam on the development of A. mellifera following larval exposure.


Assuntos
Abelhas/fisiologia , Nitrocompostos/toxicidade , Oxazinas/toxicidade , Praguicidas/toxicidade , Tiazóis/toxicidade , Animais , Glutationa Transferase/metabolismo , Larva/efeitos dos fármacos , Neonicotinoides , Tiametoxam
14.
Environ Toxicol Chem ; 36(9): 2345-2351, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28224659

RESUMO

Concern about the reproductive toxicity of plant protection products in honey bee reproducers is increasing. Because the reproductive capacity of honey bees is not currently considered during the risk assessment procedure performed during plant protection product registration, it is important to provide methods to assess such potential impairments. To achieve this aim, we used 2 different approaches that involved semifield and laboratory conditions to study the impact of fipronil on drone fertility. For each approach, the drones were reared for 20 d, from emergence to sexual maturity, and exposed to fipronil via a contaminated sugar solution. In both groups, the effects of fipronil were determined by studying life traits and fertility indicators. The results showed that the survival and maturity rates of the drones were better under laboratory conditions than under semifield conditions. Moreover, the drones reared under laboratory conditions produced more seminal fluid. Although these differences could be explained by environmental factors that may vary under semifield conditions, it was found that regardless of the approach used, fipronil did not affect survival rates, maturity rates, or semen volumes, whereas it did affect fertility by inducing a decrease in spermatozoa quantity that was associated with an increase in spermatozoa mortality. These results confirm that fipronil affects drone fertility and support the relevance of each approach for assessing the potential reproductive toxicity of plant protection products in honey bees. Environ Toxicol Chem 2017;36:2345-2351. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.


Assuntos
Abelhas/efeitos dos fármacos , Praguicidas/toxicidade , Pirazóis/toxicidade , Animais , Abelhas/fisiologia , Fertilidade/efeitos dos fármacos , Masculino , Reprodução/efeitos dos fármacos , Espermatozoides/citologia , Espermatozoides/efeitos dos fármacos
15.
J Intell ; 5(1)2017 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31162395

RESUMO

In this commentary, I discuss some critical issues in the study by Greiff, S.; Stadler, M.; Sonnleitner, P.; Wolff, C.; Martin, R., "Sometimes less is more: Comparing the validity of complex problem solving measures", Intelligence 2015, 50, 100-113. I conclude that-counter to the claims made in the original study-the specific study design was not suitable for deriving conclusions about the validity of different complex problem-solving (CPS) measurement approaches. Furthermore, a more elaborate consideration of previous CPS research was found to challenge Greiff et al.'s conclusions even further. Therefore, I argue that researchers should be aware of the differences between several kinds of CPS assessment tools and conceptualizations when the validity of CPS assessment tools is examined in future research.

16.
Sci Rep ; 6: 31430, 2016 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-27578396

RESUMO

Honeybee colony survival strongly relies on the queen to overcome worker losses exposed to combined stressors like pesticides and parasites. Queen's capacity to withstand these stressors is however very little known. The effects of the common neonicotinoid pesticide imidacloprid in a chronic and sublethal exposure together with the wide distributed parasite Nosema ceranae have therefore been investigated on queen's physiology and survivorship in laboratory and field conditions. Early physiological changes were observed on queens, particularly the increase of enzyme activities (catalase [CAT] and glutathione-S-transferase [GST] in the heads) related to protective responses to xenobiotics and oxidative stress against pesticide and parasite alone or combined. Stressors also alter the activity of two other enzymes (carboxylesterase alpha [CaE α] and carboxylesterase para [CaE p] in the midguts) involved in metabolic and detoxification functions. Furthermore, single and combined effects of pesticide and parasite decrease survivorship of queens introduced into mating hives for three months. Because colony demographic regulation relies on queen's fertility, the compromise of its physiology and life can seriously menace colony survival under pressure of combined stressors.


Assuntos
Abelhas/efeitos dos fármacos , Abelhas/microbiologia , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Praguicidas/toxicidade , Vittaforma/fisiologia , Animais , Abelhas/fisiologia , Encéfalo/enzimologia , Carboxilesterase/metabolismo , Catalase/metabolismo , Feminino , Glutationa Transferase/metabolismo , Proteínas de Insetos/metabolismo , Intestinos/enzimologia , Estimativa de Kaplan-Meier , Microsporidiose/mortalidade , Microsporidiose/patologia , Microsporidiose/veterinária
17.
Sci Rep ; 6: 31904, 2016 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-27549030

RESUMO

A species that requires sexual reproduction but cannot reproduce is doomed to extinction. The important increasing loss of species emphasizes the ecological significance of elucidating the effects of environmental stressors, such as pesticides, on reproduction. Despite its special reproductive behavior, the honey bee was selected as a relevant and integrative environmental model because of its constant and diverse exposure to many stressors due to foraging activity. The widely used insecticide Fipronil, the use of which is controversial because of its adverse effects on honey bees, was chosen to expose captive drones in hives via syrup contaminated at 0.1 µg/L and gathered by foragers. Such environmental exposure led to decreased spermatozoa concentration and sperm viability coupled with an increased sperm metabolic rate, resulting in drone fertility impairment. Subsequently, unexposed queens inseminated with such sperm exhibited fewer spermatozoa with lower viability in their spermatheca, leaving no doubt about the detrimental consequences for the reproductive potential of queens, which are key for colony sustainability. These findings suggest that pesticides could contribute to declining honey bee populations through fertility impairment, as exemplified by Fipronil. More broadly, reproductive disorders should be taken into consideration when investigating the decline of other species.


Assuntos
Abelhas/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Pirazóis/toxicidade , Comportamento Sexual Animal/efeitos dos fármacos , Animais , Abelhas/fisiologia , Feminino , Fertilidade/efeitos dos fármacos , Inseticidas/toxicidade , Masculino , Reprodução/efeitos dos fármacos , Comportamento Sexual Animal/fisiologia , Espermatozoides/efeitos dos fármacos , Espermatozoides/fisiologia
18.
Ecotoxicol Environ Saf ; 127: 205-13, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26866756

RESUMO

In the agricultural environment, honey bees may be exposed to combinations of pesticides. Until now, the effects of these combinations on honey bee health have been poorly investigated. In this study, we assessed the impacts of biological and chemical insecticides, combining low dietary concentrations of Bacillus thuringiensis (Bt) spores (100 and 1000µg/L) with the chemical insecticide fipronil (1µg/L). In order to assess the possible effects of Cry toxins, the Bt kurstaki strain (Btk) was compared with a Bt strain devoid of toxin-encoding plasmids (Bt Cry(-)). The oral exposure to fipronil and Bt spores from both strains for 10 days did not elicit significant effects on the feeding behavior and survival after 25 days. Local and systemic physiological effects were investigated by measuring the activities of enzymes involved in the intermediary and detoxication metabolisms at two sampling dates (day 10 and day 20). Attention was focused on head and midgut glutathione-S-transferase (GST), midgut alkaline phosphatase (ALP), abdomen glyceraldehyde-3-phosphate dehydrogenase (GAPD) and glucose-6-phosphate dehydrogenase (G6PD). We found that Bt Cry(-) and Btk spores induced physiological modifications by differentially modulating enzyme activities. Fipronil influenced the enzyme activities differently at days 10 and 20 and, when combined with Bt spores, elicited modulations of some spore-induced physiological responses. These results show that an apparent absence of toxicity may hide physiological disruptions that could be potentially damaging for the bees, especially in the case of combined exposures to other environmental stressors.


Assuntos
Antiparasitários/toxicidade , Bacillus thuringiensis/fisiologia , Toxinas Bacterianas/toxicidade , Abelhas/fisiologia , Inseticidas/toxicidade , Pirazóis/toxicidade , Agricultura , Animais , Abelhas/microbiologia , Exposição Ambiental/efeitos adversos , Glucosefosfato Desidrogenase/metabolismo , Controle Biológico de Vetores/métodos , Praguicidas/metabolismo , Esporos Bacterianos
19.
PLoS Pathog ; 10(8): e1004323, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25144447

RESUMO

Over the past fifty years, annual honeybee (Apis mellifera) colony losses have been steadily increasing worldwide. These losses have occurred in parallel with the global spread of the honeybee parasite Varroa destructor. Indeed, Varroa mite infestations are considered to be a key explanatory factor for the widespread increase in annual honeybee colony mortality. The host-parasite relationship between honeybees and Varroa is complicated by the mite's close association with a range of honeybee viral pathogens. The 10-year history of the expanding front of Varroa infestation in New Zealand offered a rare opportunity to assess the dynamic quantitative and qualitative changes in honeybee viral landscapes in response to the arrival, spread and level of Varroa infestation. We studied the impact of de novo infestation of bee colonies by Varroa on the prevalence and titres of seven well-characterised honeybee viruses in both bees and mites, using a large-scale molecular ecology approach. We also examined the effect of the number of years since Varroa arrival on honeybee and mite viral titres. The dynamic shifts in the viral titres of black queen cell virus and Kashmir bee virus mirrored the patterns of change in Varroa infestation rates along the Varroa expansion front. The deformed wing virus (DWV) titres in bees continued to increase with Varroa infestation history, despite dropping infestation rates, which could be linked to increasing DWV titres in the mites. This suggests that the DWV titres in mites, perhaps boosted by virus replication, may be a major factor in maintaining the DWV epidemic after initial establishment. Both positive and negative associations were identified for several pairs of viruses, in response to the arrival of Varroa. These findings provide important new insights into the role of the parasitic mite Varroa destructor in influencing the viral landscape that affects honeybee colonies.


Assuntos
Abelhas/parasitologia , Abelhas/virologia , Interações Hospedeiro-Parasita , Infestações por Ácaros/veterinária , Varroidae/parasitologia , Viroses/veterinária , Animais , Infestações por Ácaros/epidemiologia , Infestações por Ácaros/parasitologia , Nova Zelândia , Prevalência , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Viroses/epidemiologia , Viroses/parasitologia
20.
PLoS One ; 8(8): e72016, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23940803

RESUMO

Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen) necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pollen availability on bee health is well-established but whether quality and diversity of pollen diets can modify bee health remains largely unknown. We therefore tested the influence of pollen diet quality (different monofloral pollens) and diversity (polyfloral pollen diet) on the physiology of young nurse bees, which have a distinct nutritional physiology (e.g. hypopharyngeal gland development and vitellogenin level), and on the tolerance to the microsporidian parasite Nosemaceranae by measuring bee survival and the activity of different enzymes potentially involved in bee health and defense response (glutathione-S-transferase (detoxification), phenoloxidase (immunity) and alkaline phosphatase (metabolism)). We found that both nurse bee physiology and the tolerance to the parasite were affected by pollen quality. Pollen diet diversity had no effect on the nurse bee physiology and the survival of healthy bees. However, when parasitized, bees fed with the polyfloral blend lived longer than bees fed with monofloral pollens, excepted for the protein-richest monofloral pollen. Furthermore, the survival was positively correlated to alkaline phosphatase activity in healthy bees and to phenoloxydase activities in infected bees. Our results support the idea that both the quality and diversity (in a specific context) of pollen can shape bee physiology and might help to better understand the influence of agriculture and land-use intensification on bee nutrition and health.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Abelhas/fisiologia , Pólen , Ração Animal/normas , Animais , Sobrevida
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...