The recent concern over CCD has much in common with the historical "Isle of Wight Disease" episode, and many lessons can be learned. Initial concern about colony losses in one particular area, the USA, has led to global media attention.

SummaryGrowing evidence indicates that European managed honey bees are in decline, but information for Europe remains patchy and localized. Here we compile data from 18 European countries to assess trends in the number of honey bee colonies and beekeepers between 1965 and 2005. We found consistent declines in colony numbers in central European countries and some increases in Mediterranean countries. Beekeeper numbers have declined in all of the European countries examined. Our data support the view that honey bees are in decline at least in some regions, which is probably closely linked to the decreasing number of beekeepers. Our data on colony numbers and beekeepers must, however, be interpreted with caution due to different approaches and socioeconomic factors in the various countries, thereby limiting their comparability. We therefore make specific recommendations for standardized methodologies to be adopted at the national and global level to assist in the future monitoring of honey bees. ResumenCada vez hay más pruebas que indican que las abejas europeas manejadas están en declive, pero la información para Europa sigue desigual y localizada. Aquí compilamos datos a partir de 18 países europeos para evaluar las tendencias respecto al número de colonias de la abeja de la miel y de apicultores entre 1965 y 2005. Encontramos constantes disminuciones en cuanto al número de colonias en países centroeuropeos y algún aumento en países mediterráneos. El número de apicultores ha disminuido en todos los países europeos examinados. Nuestros datos apoyan la visión de que las abejas de la miel están disminuyendo por lo menos en algunas regiones, lo que está probablemente ligado a la disminución de apicultores. Nuestros datos sobre el número de colonias y de apicultores deben, sin embargo, ser interpretados con precaución debido a diversos enfoques y a los factores socioeconómicos en los diversos países, limitando por tanto su comparación. Por lo tanto hacemos recomendaciones específicas para que sean a...

Elevated winter losses of managed honeybee colonies are a major concern, but the underlying mechanisms remain controversial. Among the suspects are the parasitic mite Varroa destructor , the microsporidian Nosema ceranae , and associated viruses. Here we hypothesize that pathogens reduce the life expectancy of winter bees, thereby constituting a proximate mechanism for colony losses. A monitoring of colonies was performed over 6 months in Switzerland from summer 2007 to winter 2007/2008. Individual dead workers were collected daily and quantitatively analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV), N. ceranae , and expression levels of the vitellogenin gene as a biomarker for honeybee longevity. Workers from colonies that failed to survive winter had a reduced life span beginning in late fall, were more likely to be infected with DWV, and had higher DWV loads. Colony levels of infection with the parasitic mite Varroa destructor and individual infections with DWV were also associated with reduced honeybee life expectancy. In sharp contrast, the level of N. ceranae infection was not correlated with longevity. In addition, vitellogenin gene expression was significantly positively correlated with ABPV and N. ceranae loads. The findings strongly suggest that V. destructor and DWV (but neither N. ceranae nor ABPV) reduce the life span of winter bees, thereby constituting a parsimonious possible mechanism for honeybee colony losses.

Across the Northern hemisphere, managed honey bee colonies, Apis mellifera, are currently affected by abrupt depopulation during winter and many factors are suspected to be involved, either alone or in combination. Parasites and pathogens are considered as principal actors, in particular the ectoparasitic mite Varroa destructor, associated viruses and the microsporidian Nosema ceranae. Here we used long term monitoring of colonies and screening for eleven disease agents and genes involved in bee immunity and physiology to identify predictive markers of honeybee colony losses during winter. The data show that DWV, Nosema ceranae, Varroa destructor and Vitellogenin can be predictive markers for winter colony losses, but their predictive power strongly depends on the season. In particular, the data support that V. destructor is a key player for losses, arguably in line with its specific impact on the health of individual bees and colonies.

Queen health is crucial to colony survival of social bees. Recently, queen failure has been proposed to be a major driver of managed honey bee colony losses, yet few data exist concerning effects of environmental stressors on queens. Here we demonstrate for the first time that exposure to field-realistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees (Apis mellifera). In pesticide-exposed queens, reproductive anatomy (ovaries) and physiology (spermathecal-stored sperm quality and quantity), rather than flight behaviour, were compromised and likely corresponded to reduced queen success (alive and producing worker offspring). This study highlights the detriments of neonicotinoids to queens of environmentally and economically important social bees and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances.