No abstract

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

Managed honey bee colony losses are of concern in the USA and globally. This survey, which documents the rate of colony loss in the USA during the 2015-2016 season, is the tenth report of winter losses, and the fifth of summer and annual losses. Our results summarize the responses of 5725 valid survey respondents, who collectively managed 427,652 colonies on 1 October 2015, an estimated 16.1% of all managed colonies in the USA. Responding beekeepers reported a total annual colony loss of 40.5% [95% CI 39.8-41.1%] between 1 April 2015 and 1 April 2016. Total winter colony loss was 26.9% [95% CI 26.4-27.4%] while total summer colony loss was 23.6% [95% CI 23.0-24.1%], making this the third consecutive year when summer losses have approximated to winter losses. Across all operation types, 32.3% of responding beekeepers reported no winter losses. Whilst the loss rate in the winter of 2015-2016 was amongst the lowest winter losses recorded over the ten years this survey has been conducted, 59.0% (n = 3378) of responding beekeepers had higher losses than they deemed acceptable. Encuesta nacional 2015-2016 sobre pé rdidas anuales de colonias de la abeja de la miel manejada en los EE.UU Las pérdidas de colonias de abejas manejadas son preocupantes en los Estados Unidos y en el mundo. Esta encuesta, que documenta la tasa de pérdida de colonias en los EE.UU. durante la temporada 2015-2016, es el décimo informe de las pérdidas de invierno, y el quinto de las pérdidas de verano y anuales. Nuestros resultados resumen las respuestas de 5.725 encuestados válidos, quienes colectivamente manejaron 427.652 colonias el 1 de octubre de 2015, un 16.1% de todas las colonias manejadas en los Estados Unidos. Los apicultores respondieron con una pérdida total de colonias anual del 40.5% [IC del 95%: 39.8-41.1%] entre el 1 de abril de 2015 y el 1 de abril de 2016. La pérdida total de colonias de invierno fue del 26.9% [IC del 95%: 26.4-27.4%], y las de verano del 23.6% [IC del 95%: 23.0-24.1%], lo que lo convierte en el tercer año consecutivo en que las pérdidas del verano se han aproximado a las pérdidas de invierno. En todos los tipos de operaciones, el 32.3% de los apicultores que respondieron no reportaron pérdidas de invierno. Mientras que la tasa de pérdidas en el invierno de 2015-2016 fue una de las pérdidas de invierno más bajas registradas durante los diez años que se han realizado esta encuesta, el 59.0% (n = 3.378) de los apicultores que respondieron tuvieron mayores pérdidas de las que consideraban aceptables.

-The US National Honey Bee Disease Survey sampled colony pests and diseases from 2009 to 2014. We verified the absence of Tropilaelaps spp., the Asian honey bee (Apis cerana ), and slow bee paralysis virus. Endemic health threats were quantified, including Varroa destructor , Nosema spp., and eight honey bee viruses. Varroa loads varied across years, with annual fall peaks; Nosema peaked January to April. Migratory beekeepers had significantly lower Varroa prevalence (84.9 vs. 97.0 %) and loads (3.65 ± 0.28 vs. 5.99 ± 0.22) than stationary operations, while Nosema was more prevalent (59.9 vs. 46.7 %) in migratory colonies. Since 2010, chronic bee paralysis virus prevalence doubled annually. We detected strong positive relationships between V. destructor and Varroa -transmitted viruses, between Nosema and Lake Sinai virus 2, and a positive relationship across several viral pathogens of bees. The results provide a disease baseline to help identify drivers of poor bee health.Apis mellifera / disease survey / pests / parasite / USA