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Although Apis mellifera is the dominant managed pollinator used to enhance crop production, the variation of its foraging behaviour among crop-cultivars is not considered as a factor influencing pollination success and, thus, yield. Almond production is highly dependent on cross-pollination. Herein, we examined honey bees foraging behaviour and pollen limitation in 'Nonpareil' and 'Independence' cultivars. Nectar and pollen-foragers differed in the flower handling behaviour, regardless of the cultivar. However, most bees on 'Independence' flowers collected pollen in the morning and bees exhibited less floral constancy in this cultivar, potentially promoting cross-pollination. Also, supplementation of 'Nonpareil' flowers with 'Independence' pollen had a positive effect in nut-set, suggesting that higher visitation rates are needed to increase yield. Our study underlines the importance of integrating behavioural knowledge of pollinators to optimize practices in pollinator-dependent crops. [ABSTRACT FROM AUTHOR]

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Honeybees are essential components to modern agriculture and economy. However, a continuous increase in cases of colony losses and colony depopulation are being reported worldwide. This critical situation has put the fragile equilibrium between bees and plants on the edge. As a consequence, several scientists have begun to focus their lines of research on this issue. Most researchers agree that there is no single explanation for the observed colony losses. Instead, these losses result from a synergistic interaction between different stressors. South America is not the exception; several cases of colony losses and colony depopulation were reported by beekeepers throughout the continent, yet no accurate data has been published to date. Therefore, this article attempts to analyze the past and present situation of honeybee health in South America, specifically in Argentina, Chile, Uruguay, Brazil, and Venezuela. Furthermore, it is intended to serve as a comparison to future colony losses, as well as to provide guidance for future hypothesis-driven research on the causes of colony mortality. We evaluate the impact of the main parasites and pathogens affecting honeybee colonies and discuss the role of each with respect to reported honeybee losses. We also contemplate the main challenges that each nation must confront with regards to honeybee health. [ABSTRACT FROM AUTHOR]

Honey bee colonies are threatened by different stress factors around the world. Considerable efforts are being devoted to understanding honey bee defences to confront different kinds of stress factors. Despite the importance of honey bee hemocytes in resisting disease, detailed information about their role in response to challenge is still scarce. This manuscript combines the results obtained in studies which focused on the cellular defences of Apis mellifera, aiming to show how the understanding of the cellular components of the immune system is central to developing new strategies to enhance bees' fitness. [ABSTRACT FROM AUTHOR]

The primary food of adult honey bees ( Apis mellifera) is honey prepared by bees from nectar, provided by plants in order to stimulate the bee's pollination service. Nectar consists of carbohydrates, amino acids and water, as well as other minor compounds whose proportion varies among plant species and whose biological implications in the honey bee physiology require intense research. Several environmental stressors are causing the decline of bee colonies, and thereby, we tried to connect the nutritional quality of bee's diet with the strength of the bee's immune system. The phytohormone abscisic acid (ABA) is present in nectar, honey and adult honey bees. It has been demonstrated that ABA stimulates innate immune defences in animal cells. However, the influence of ABA on A. mellifera's health and fitness is unknown. Here, we show that honey bees fed with an ABA supplement in field experiments resulted in (i) the appearance of ABA in larvae and adult bees, (ii) enhanced haemocyte response to non-self recognition, (iii) improved wound healing and granulocyte and plasmatocyte activation and (iv) maximum adult bee population after the winter and increased pesticide tolerance. The results indicate that the naturally occurring compound ABA has a positive influence in honey bee immunity. ABA emerges as a potent booster of immune defence in A. mellifera and may be useful in addressing the colony losses threatening apiculture and pollination service worldwide. [ABSTRACT FROM AUTHOR]

The high annual losses of managed honey bees (Apis mellifera) has attracted intensive attention, and scientists have dedicated much effort trying to identify the stresses affecting bees. There are, however, no simple answers; rather, research suggests multifactorial effects. Several works have been reported highlighting the relationship between bees' immunosuppression and the effects of malnutrition, parasites, pathogens, agrochemical and beekeeping pesticides exposure, forage dearth and cold stress. Here we analyze a possible connection between immunity-related signaling pathways that could be involved in the response to the stress resulted from Varroa-virus association and cold stress during winter. The analysis was made understanding the honey bee as a superorganism, where individuals are integrated and interacting within the colony, going from social to individual immune responses. We propose the term "Precision Nutrition" as a way to think and study bees' nutrition in the search for key molecules which would be able to strengthen colonies' responses to any or all of those stresses combined. [ABSTRACT FROM AUTHOR]

In temperate climates, beekeeping operations suffer colony losses and colony depopulation of Apis mellifera during overwintering, which are associated with biotic and abiotic stressors that impact bees' health. In this work, we evaluate the impacts of abscisic acid (ABA) dietary supplementation on honey bee colonies kept in Langstroth hives. The effects of ABA were evaluated in combination with two different beekeeping nutritional strategies to confront overwintering: "honey management" and "syrup management". Specifically, we evaluated strength parameters of honey bee colonies (adult bee and brood population) and the population dynamics of Nosema (prevalence and intensity) associated with both nutritional systems and ABA supplementation during the whole study (late autumn-winter-early spring). The entire experiment was designed and performed with a local group of beekeepers, "Azahares del sudeste", who showed interest in answering problems associated with the management of honey bee colonies during the winter. The results indicated that the ABA supplementation had positive effects on the population dynamics of the A. mellifera colonies during overwintering and on the nosemosis at colony level (prevalence) in both nutritional strategies evaluated. [ABSTRACT FROM AUTHOR]

This correction stands to correct the last sentence found in the caption of Figure 2 where it reads, "Three independent experiments were performed and a total of 18 larvae per treatment were analyzed." [ABSTRACT FROM AUTHOR]