The health of managed and wild-living Western honey bee colonies, Apis mellifera, on Guam

Abstract

A survey conducted as part of the National Honey Bee Survey from 2013 to 2020 quantified the managed honey bee hives on Guam, sampled accessible wild-living colonies, and described associated diseases and pests. During this period the number of managed bee colonies increased from 20 to 121 which was associated with the formation of the Guam Beekeepers Association. Managed Apis mellifera colonies on Guam had significantly fewer parasites and diseases than reported in the USA. The Varroa mite, Varroa destructor, was detected in 2014 in a wild-living colony in southern Guam. The greater banded hornet, Vespa tropica, was first observed on Guam in 2016, with honey bee depredations observed in 2017. Nosema ceranae was initially detected in wild-living and managed colonies in 2013 and has been consistently observed since that time with little apparent effect on colony health as there have been no recorded colony losses in apiaries. No small hive beetle, Aethina tumida, Tropilaelaps mite, Tropilaelaps spp, American foulbrood, Paenibacillus larvae, European foulbrood, Melissococcus plutonius, chalkbrood, Ascosphaera sp. and 11 additional viral diseases of the 22 known to infest honey bees, including deformed wing virus, were observed.