\u3ci\u3eVarroa\u3c/i\u3e mites and honey bee health: can \u3ci\u3eVarroa\u3c/i\u3e explain part of the colony losses?

Since 2006, disastrous colony losses have been reported in Europe and North America. The causes of the losses were not readily apparent and have been attributed to overwintering mortalities and to a new phenomenon called Colony Collapse Disorder. Most scientists agree that there is no single explanation for the extensive colony losses but that interactions between different stresses are involved. As the presence of Varroa in each colony places an important pressure on bee health, we here address the question of how Varroa contributes to the recent surge in honey bee colony losses

Feromonas emitidas pelas rainhas da abelha ibérica (Apis mellifera iberiensis): desenvolvimento de um sistema de recolha In Vivo por micro-extração em fase sólida (SPME)

As feromonas são infoquímicos segregados pelas glândulas de um animal que estimulam uma resposta comportamental ou fisiológica em outro animal da mesma espécie [1]. São misturas complexas, capazes de induzir uma resposta em concentrações muito baixas. Podem ser altamente voláteis, com pesos moleculares baixos e de rápida difusão no ar ou menos voláteis, mais pesados, adsorvidos na superfície do corpo e passados por contato corporal [2]. Numa colónia de abelhas existem duas castas femininas, uma rainha e milhares de obreiras. A rainha, normalmente, a única fêmea reprodutora da colónia, é o fator regulador mais importante de uma colónia. Esta regulação é conseguida através das feromonas, produzidas em diferentes glândulas e emitidas como uma mistura complexa conhecida como o sinal da rainha. Este induz várias modificações fisiológicas e comportamentais nas abelhas obreiras que resultam na manutenção da homeostase da colónia através do estabelecimento da hierarquia social e da preservação da supremacia reprodutiva da rainha [2). Neste trabalho pretendeu-se analisar as feromomas emitidas in vivo pelas rainhas da abelha ibérica (Apis mellifera iberiensis). Para isso recorreu-se à técnica de micro-extração em fase sólida (SPME), por ser uma técnica versátil, precisa e rápida, baseada na adsorção dos voláteis numa fase de extração imobilizada sobre a superfície de uma fibra de sílica fundida. O trabalho foi realizado com colónias de abelhas ibéricas provenientes de um apiário experimental situado em Bragança. A criação de rainhas foi realizada seguindo métodos padrão de apicultura, método Doolitle [3]. Após a operculação dos alvéolos reais, estes foram transferidos para o laboratório, e mantidos a 35 ºC e 70% de humidade relativa. Após o nascimento as rainhas foram mantidas durante sete dias em gaiolas na companhia de abelhas ama, com alimentação artificial e água. Após esse período, procedeu-se à recolha de voláteis colocando a rainha num frasco âmbar de 50 ml. A fibra de SPME, protegida por uma rede metálica, foi introduzida no frasco, sendo a amostragem efectuada durante 15 min, com uma temperatura de 28 ºC e 50 % de humidade relativa. Foi usada uma fibra de polidimetilsiloxano/divinilbenzeno (Supelco SPME fiber 57326U). Após a recolha a fibra foi imediatamente colocada num aparelho de cromatografia gasosa acoplada a espectrometria de massa (GC/MS) e desorbida durante 5 min a 250 ºC em modo splitless. Esta técnica demonstrou ser adequada para recolher todos os compostos voláteis emitidos pela abelha, minimizando situações de stress da abelha.Os autores agradecem à Fundação para a Ciência e Tecnologia (FCT, Portugal) e ao FEDER sob o programa PT2020 pelo financiamento ao CIMO (UID/AGR/00690/2013). Soraia I. Falcão agradece à FCT pela bolsa Post-Doc SFRH/BPD/118987/2016.info:eu-repo/semantics/publishedVersio

Behavioral Genetics of the Interactions between Apis mellifera and Varroa destructor

The western honeybee Apis mellifera exhibits a diverse set of adaptations in response to infestations by its most virulent disease-causing agent, the ectoparasitic mite Varroa destructor. In this study, we investigated the effect of honeybee pupae genotype on the expression of four host and parasite traits that are associated with the reproductive phase of the mite in the brood of its host. We first phenotyped cells containing bee pupae to assess their infestation status, their infestation level, the reproductive status of the mites, and the recapping of cells by adult workers. We then genotyped individual pupae with five microsatellites markers to compare these phenotypes across full sister groups. We found that the four phenotypes varied significantly in time but did not across the subfamilies within the colonies. These findings show that V. destructor mites do not differentially infest or reproduce on some particular honeybee patrilines, and that workers do not target preferentially specific pupae genotypes when performing recapping. These findings bring new insights that can help designing sustainable mite control strategies through breeding and provide new insights into the interactions between A. mellifera and V. destructor

Effets de Nosema ceranae (Microsporidia) sur la santé de l'abeille domestique Apis mellifera L. (changements physiologiques et comportementaux)

Nosema ceranae est un parasite émergeant d Apis mellifera décrit dans certaines régions comme la cause majeure de la mortalité des abeilles. Dans d autres cas, il est soupçonné d affaiblir les colonies par l interaction avec d autres facteurs de pression de l environnement. Dans le cadre du phénomène global de la mortalité des abeilles, nous avons orienté nos recherches vers l étude des effets N. ceranae, en faisant l hypothèse que ce parasite est capable d induire des changements comportementaux chez A. mellifera dus à des altérations physiologiques, ce qui pourrait éventuellement perturber l organisation sociale et aboutir à la mort de la colonie. Etant donné cette hypothèse, trois domaines d étude ont été inclus dans notre recherche, (i) les effets de N. ceranae sur l organisation sociale de la colonie, (ii) les mécanismes moléculaires à la base des effets chez les abeilles parasitées, et (iii) les différences en virulence d isolats de N. ceranae ce qui pourrait expliquer la variation des effets du parasite chez l abeille. Nous avons obtenu trois résultats majeurs. D abord, nous avons constaté des modifications dans la structure sociale des abeilles après l infection. Ces changements sembleraient contribuer à la survie de la colonie constituant probablement un mécanisme d immunité sociale. Ce mécanisme géré par un signal phéromonal, permettrait de diminuer la transmission du parasite au sein de la colonie et prolonger la survie des abeilles saines. Ensuite, nous avons mis en évidence des effets sur la physiologie de l intestin de l abeille qui pourraient causer sa mort : l induction du stress oxydatif et l inhibition du renouvellement cellulaire de l épithélium. Finalement, nos résultats suggèrent que certaines caractéristiques de l hôte et conditions environnementales augmenteraient la probabilité de N. ceranae d induire la mort. En conclusion, N. ceranae a le potentiel de causer la mort des abeilles, cependant, la colonie pourrait contrer l infection, par exemple, par de mécanismes d immunité sociale, or, la réponse générale à l infection dépendrait des caractéristiques de l hôte en combinaison avec les conditions de l environnement. Le phénomène d effondrement de colonies à l échelle mondiale a mis en évidence la fragilité du système colonie d abeilles environnement. L étude de chaque facteur participant au système, en autres, parasites, pesticides, changements dans l environnement, pratiques apicoles, est essentielle pour une meilleure compréhension de toutes les interactions qui maintiennent l équilibre écologique des coloniesNosema ceranae is an emergent parasite of the honey bee Apis mellifera. In some regions it has been found to be the main reason for bee mortality, while in others it is suspected of weakening honey bee colonies by interacting with other environmental stressors. In the context of worldwide colony losses, we focus our research on the study of N. ceranae, with the hypothesis that this parasite is able to induce behavioral changes in bees through physiological modifications, which could alter social organization and cause colony death. Given this hypothesis, the program of study falls into three areas; (i) N. ceranae effects on colony social organization, (ii) molecular mechanisms of N. ceranae infection underlying observed effects, and (iii) differences in virulence of N. ceranae strains which could explain the diversity of parasite effects. We obtained three main results. First, we observed modifications in honey bee social structure after infection. This mechanism under pheromone control, would reduce parasite transmission within the colony and increase the lifespan of healthy bees. These changes may contribute to colony survival as part of a mechanism of social immunity. Second, we found two mechanisms whereby the pathogen affects the physiology of bee midgut epithelium that could lead to host mortality: oxidative stress and the inhibition of cellular renewal. Finally, our results suggest that certain host and environmental conditions increase the probability that N. ceranae will cause bee mortality. In conclusion, N. ceranae has the potential to cause bee death, however at colony level bees might counteract infection through, for example, social immunity mechanisms; although, overall honey bee response to infection would depend on characteristics of the host in combination with environmental conditions. Worldwide colony losses phenomenon have highlighted the fragility of the honey bee colony environment system. The study of each factor involve in this system, including parasites, pesticides, environmental changes and beekeeping practices, is essential to better understand all of the interactions that maintain the ecological balance of honey bee coloniesAVIGNON-Bib. numérique (840079901) / SudocSudocFranceF

Reproductive success of the parasitic mite (Varroa destructor) is lower in honeybee colonies that target infested cells with recapping

Cell recapping is a behavioural trait of honeybees (Apis mellifera) where cells with developing pupae are uncapped, inspected, and then recapped, without removing the pupae. The ectoparasitic mite Varroa destructor, unarguably the most destructive pest in apiculture world-wide, invades the cells of developing pupae to feed and reproduce. Honeybees that target mite infested cells with this behaviour may disrupt the reproductive cycle of the mite. Hence, cell recapping has been associated with colony-level declines in mite reproduction. In this study we compared the colony-level efficacy of cell recapping (how often infested cells are recapped) to the average mite fecundity in A. mellifera. Our study populations, known to be adapted to V. destructor, were from Avignon, France, Gotland, Sweden, and Oslo, Norway, and were compared to geographically similar, treated control colonies. The results show that colonies with a higher recapping efficacy also have a lower average mite reproductive success. This pattern was likely driven by the adapted populations as they had the largest proportion of highly-targeted cell recapping. The consistent presence of this trait in mite-resistant and mite-susceptible colonies with varying degrees of expression may make it a good proxy trait for selective breeding on a large scale

Varroakvalstrets effekt på virus i angripna honungsbisamhällen

Vilken effekt har varroakvalster på de virus som infekterar bisamhällen? Forskare vid INRA (Frankrikes nationella institution för jordbruksforskning) i Avignon, Frankrike, University of Otago i Nya Zeeland och Sveriges lantbruksuniversitet (SLU), nyttjade en unik situation i Nya Zeeland där landet, liksom Sverige, har varroaangripna respektive icke angripna regioner. Varroa är relativt nyetablerad i Nya Zeeland. Den påvisades först på Nordön år 2000, och har stadigt spridits söderut under de 14 åren som gått sedan introduktionen. Forskarna har undersökt virusprofilen hos bisamhällena sedan etablering av kvalstret i de olika regionerna. Studien, som publicerades 2014, visar en drastisk ändring av det virala landskapet i bisamhällena som sammanfaller med etablering av varroa, vilket ökar risken för synergier mellan olika virus som är skadliga för bina

New insights into honey bee (Apis mellifera) pheromone communication. Is the queen mandibular pheromone alone in colony regulation?

<p>Abstract</p> <p>Background</p> <p>In social insects, the queen is essential to the functioning and homeostasis of the colony. This influence has been demonstrated to be mediated through pheromone communication. However, the only social insect for which any queen pheromone has been identified is the honey bee (<it>Apis mellifera</it>) with its well-known queen mandibular pheromone (QMP). Although pleiotropic effects on colony regulation are accredited to the QMP, this pheromone does not trigger the full behavioral and physiological response observed in the presence of the queen, suggesting the presence of additional compounds. We tested the hypothesis of a pheromone redundancy in honey bee queens by comparing the influence of queens with and without mandibular glands on worker behavior and physiology.</p> <p>Results</p> <p>Demandibulated queens had no detectable (E)-9-oxodec-2-enoic acid (9-ODA), the major compound in QMP, yet they controlled worker behavior (cell construction and queen retinue) and physiology (ovary inhibition) as efficiently as intact queens.</p> <p>Conclusions</p> <p>We demonstrated that the queen uses other pheromones as powerful as QMP to control the colony. It follows that queens appear to have multiple active compounds with similar functions in the colony (pheromone redundancy). Our findings support two hypotheses in the biology of social insects: (1) that multiple semiochemicals with synonymous meaning exist in the honey bee, (2) that this extensive semiochemical vocabulary exists because it confers an evolutionary advantage to the colony.</p

Influence of environmental experience on aversive conditioning in honey bees (Apis mellifera L.)

International audiencePrevious experience in a natural environment with a stimulus has lasting influences on honey bee behavior, as demonstrated in laboratory studies of appetitive conditioning. However, it is unknown whether the same holds true for studies of aversive conditioning. Aversive conditioning is important for insects such as honey bees to survive environmental risks. Previous experience in natural settings may lead to maladaptive behavioral patterns in bees exposed to new risks. This study presents the first examination of the effect of a visual stimulus presented in a naturalistic setting on aversive conditioning, using the shuttle box choice chamber paradigm. The present study examines both the effect of the visual stimuli, as well as differences present between the Apis mellifera subspecies of mellifera and ligustica. Results support the presence of behavioral biases based on the visual stimulus presented prior to the experimental sessions