Molecular ecology of the honey bee Apis mellifera L. in Ireland

Abstract

The honey bee sub-species native to Ireland is Apis mellifera mellifera, referred to locally as the Black bee. It is the same sub-species that has undergone widespread extinction across the rest of its native range in northern Europe as a consequence of habitat loss, replacement, hybridisation, and colony death caused by the novel parasite Varroa destructor. A programme to locate and selectively breed for bees resistant to V. destructor was initiated and investigations were made into the genotypes of the monitored colonies. Using a combination of mtDNA, microsatellite and SNP markers, the queen lineage and extent of hybridisation between M and C lineages in a selection of bees was determined. As a possible genetic source of resistance to the parasite, free-living, unmanaged colonies were located using a citizen science approach. They were also genotyped using the same markers and their survival was monitored. Eight apiaries were sampled for bees, brood, and pollen to investigate pollen use by Irish honey bees between apiaries and colonies located in similar rural landscapes and to make the first concurrent study of the gut bacteria of these bees. An extensive trial indicated that the process of creating a widespread breeding programme may be prohibitively difficult to achieve in an Irish context. The reasons behind this are discussed and a suggestion is made for a modular, localised model. The majority of bees genotyped, whether managed or free-living, are revealed as M-lineage by mtDNA genotyping and assigned as the sub-species native to Ireland. The citizen science approach resulted in the discovery of a large free-living bee population living in natural and artificial cavities. The survival of a number of these colonies was monitored for periods exceeding the three year limit expected of colonies infested with V. destructor. The pollen data added to our knowledge from the single previous peer-reviewed research on honey bee pollen in Ireland by revealing the use of a significant number of new plant species. These new data permit a temporal comparison between and within apiaries and are compared to a concurrent gut bacteria profile.