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Estimating the Density of Honeybee Colonies across Their Natural Range to Fill the Gap in Pollinator Decline Censuses

Authors

  • RODOLFO JAFFÉ,

    Corresponding author
    1. Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, Halle (Saale) 06120, Germany
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  • VINCENT DIETEMANN,

    1. Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, Halle (Saale) 06120, Germany
    2. Swiss Bee Research Center, Agroscope Liebefeld-Posieux Research Station ALP, Schwarzenburgstrasse 161, CH-3003 Bern, Switzerland
    3. Social Insect Research Group, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
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  • MIKE H. ALLSOPP,

    1. Honeybee Research Section, ARC-Plant Protection Research Institute, Private Bag X5017, Stellenbosch 7599, South Africa
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  • CECILIA COSTA,

    1. CRA-API, Unità di Ricerca di Apicoltura e Bachicoltura. Via di Saliceto 80, Bologna 40128, Italy
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  • ROBIN M. CREWE,

    1. Social Insect Research Group, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
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  • RAFFAELE DALL’OLIO,

    1. CRA-API, Unità di Ricerca di Apicoltura e Bachicoltura. Via di Saliceto 80, Bologna 40128, Italy
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  • PILAR DE LA RÚA,

    1. Área de Biología Animal, Departamento de Zoología y Antropología Física, Facultad de Veterinaria, Universidad de Murcia, 30100 Murcia, Spain
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  • MOGBEL A. A. EL-NIWEIRI,

    1. Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, Halle (Saale) 06120, Germany
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  • INGEMAR FRIES,

    1. Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 75007 Uppsala, Sweden
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  • NIKOLA KEZIC,

    1. Faculty of Agriculture, University of Zagreb, Svetosimunska 25, HR-10000 Zagreb, Croatia
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  • MICHAEL S. MEUSEL,

    1. Discipline of Genetics, School of Biochemistry, Genetics, and Microbiology, University of KwaZulu-Natal, Pietermaritzburg, Private Bag XO1, Scottsville 3209, South Africa
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  • ROBERT J. PAXTON,

    1. School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom
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  • TAHER SHAIBI,

    1. Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, Halle (Saale) 06120, Germany
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  • ECKART STOLLE,

    1. Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, Halle (Saale) 06120, Germany
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  • ROBIN F.A. MORITZ

    1. Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, Halle (Saale) 06120, Germany
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‡‡‡email rodolfo.jaffe@zoologie.uni-halle.de

Abstract

Abstract: Although pollinator declines are a global biodiversity threat, the demography of the western honeybee (Apis mellifera) has not been considered by conservationists because it is biased by the activity of beekeepers. To fill this gap in pollinator decline censuses and to provide a broad picture of the current status of honeybees across their natural range, we used microsatellite genetic markers to estimate colony densities and genetic diversity at different locations in Europe, Africa, and central Asia that had different patterns of land use. Genetic diversity and colony densities were highest in South Africa and lowest in Northern Europe and were correlated with mean annual temperature. Confounding factors not related to climate, however, are also likely to influence genetic diversity and colony densities in honeybee populations. Land use showed a significantly negative influence over genetic diversity and the density of honeybee colonies over all sampling locations. In Europe honeybees sampled in nature reserves had genetic diversity and colony densities similar to those sampled in agricultural landscapes, which suggests that the former are not wild but may have come from managed hives. Other results also support this idea: putative wild bees were rare in our European samples, and the mean estimated density of honeybee colonies on the continent closely resembled the reported mean number of managed hives. Current densities of European honeybee populations are in the same range as those found in the adverse climatic conditions of the Kalahari and Saharan deserts, which suggests that beekeeping activities do not compensate for the loss of wild colonies. Our findings highlight the importance of reconsidering the conservation status of honeybees in Europe and of regarding beekeeping not only as a profitable business for producing honey, but also as an essential component of biodiversity conservation.

Abstract

Resumen: Aunque la declinación de polinizadores es un amenaza global para la biodiversidad, la demografía de la abeja (Apis mellifera) no ha sido considerada por conservacionistas ya que está sesgada por la actividad de los apicultores. Para cerrar esta brecha en los censos del declive de polinizadores y proporcionar una visión amplia del estatus actual de las abejas en su rango natural, utilizamos marcadores genéticos de microsatélites para estimar las densidades de colonias y la diversidad genética en diferentes localidades en Europa, África y Asia central que tenían diferentes patrones de uso de suelo. La diversidad genética y las densidades de colonias fueron mayores en África del Sur y menores en el norte de Europa y se correlacionaron con la temperatura media anual. Sin embargo, es probable que factores de confusión no relacionados con el clima también afecten a la diversidad genética y las densidades de colonias en poblaciones de abejas. El uso de suelo mostró tener una influencia significativamente negativa sobre la diversidad genética y la densidad de colonias de abejas en todas las localidades de muestreo. La diversidad genética y densidades de colonias de las abejas muestreadas en reservas naturales de Europa fueron similares a las de paisajes agrícolas, lo que sugiere que las primeras no son silvestres sino que pudieron provenir de colmenas comerciales. Otros resultados también soportan esta idea: abejas tentativamente silvestres fueron raras en nuestras muestras europeas y la densidad promedio de colonias de abejas estimada en el continente se aproxima bastante al número promedio de colmenas comerciales reportado. Las densidades actuales de abeja europea están en el mismo rango que las encontradas en las condiciones climáticas adversas de los desiertos Kalahari y Sahara, lo que sugiere que las actividades apícolas no compensan la pérdida de colonias silvestres. Nuestros resultados resaltan la importancia de revisar el estatus de conservación de las abejas en Europa y de considerar a la apicultura no solo como un negocio rentable para la producción de miel, sino también como un componente esencial de la conservación de la biodiversidad.

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