J. M. Flores

Standard methods for fungal brood disease research

Summary Chalkbrood and stonebrood are two fungal diseases associated with honey bee brood. Chalkbrood, caused by Ascosphaera apis, is a common and widespread disease that can result in severe reduction of emerging worker bees and thus overall colony productivity. Stonebrood is caused by Aspergillus spp. that are rarely observed, so the impact on colony health is not very well understood. A major concern with the presence of Aspergillus in honey bees is the production of airborne conidia, which can lead to allergic bronchopulmonary aspergillosis, pulmonary aspergilloma, or even invasive aspergillosis in lung tissues upon inhalation by humans. In the current chapter we describe the honey bee disease symptoms of these fungal pathogens. In addition, we provide research methodologies and protocols for isolating and culturing, in vivo and in vitro assays that are commonly used to study these host pathogen interactions. We give guidelines on the preferred methods used in current research and the application of molecular techniques. We have added photographs, drawings and illustrations to assist bee-extension personnel and bee scientists in the control of these two diseases.

Hygienic behaviour of Apis mellifera iberica against brood cells artificially infested with varroa

SUMMARY Hygienic behaviour forms one of the bases of tolerance of the Asian honey bee (Apis cerana) to varroa. This behaviour can also play an important role in the tolerance of the European honey bee (A. mellifera) towards the mite. The hygienic behavioural response of bees over a period of 24 h towards worker brood cells of A. mellifera iberica artificially infested with varroa was studied. When bees detected cells containing mites, in some instances both brood and mites were removed, whereas in others only the mite was removed. When a single mite was placed in each cell, hygienic behaviour was not induced, only 0.74% of infested cells had mites removed. Using two or three mites per cell, this response increased significantly, with 8.01% and 16.62% of infested cells with mites removed, respectively. A positive correlation (P < 0.05, r = 0.49) was found in hygienic behaviour towards cells artificially infested with two or three mites. A second experiment was conducted to compare the response of bees to live or dead mites inoculated into the cells. When three mites were placed in each cell, no difference in response to dead or live mites was observed (P = 0.686).

Viability of honeybee colonies exposed to sunflowers grown from seeds treated with the neonicotinoids thiamethoxam and clothianidin

In this study, honeybee colonies were monitored in a field study conducted on sunflowers grown from seeds treated with the systemic neonicotinoids thiamethoxam or clothianidin. This field trial was carried out in different representative growing areas in Spain over a beekeeping season. The health and development of the colonies was assessed by measuring factors that have a significant influence on their strength and overwintering ability. The parameters assessed were: colony strength (adult bees), brood development, amount of pollen and honey stores and presence and status of the queen. The concentration of residues (clothianidin and thiamethoxam) in samples of beebread and in adult bees was at the level of ng.g-1; in the ranges of 0.10-2.89 ng g-1 and 0.05-0.12 ng g-1; 0.10-0.37 ng g-1 and 0.01-0.05 ng g-1, respectively. Multivariate models were applied to evaluate the interaction among factors. No significant differences were found between the honeybee colonies of the different treatment groups, either exposed or not to the neonicotinoids. The seasonal development of the colonies was affected by the environmental conditions which, together with the initial strength of the bee colonies and the characteristics of the plots, had a significant effect on the different variables studied.