THE TORMENTIL MINING BEE
A small, elusive, black solitary bee - known as the Tormentil mining bee Andrena tarsata.
Rarity: This national priority species has been lost from over half of its habitat since the 1970s
Causes of decline: Loss of specific microhabitats, through loss of sandy nesting areas and changes in grazing management
It has an associated Nomad bee Nomada roberjeotiana, a kleptoparasite that takes over its host nest killing its eggs; this is even rare than its host
Andrena tarsata is a northern European bee, that becomes scarcer further south. Stöckhert (1933) describes it as being a boreal-alpine species. Its range extends from central Fennoscandia south to Spain, and eastwards to the former Czechoslovakia and USSR (GR Else, BWARS website).
It is found across the UK in England, Wales and Scotland, with strongholds in Yorkshire and the South West (Cornwall, Devon and Dorset).
The Tormentil mining bee is widespread, however the species has been lost from 50% of its former sites since 1970 so its distribution is fragmented and localised (BWARS data).
The South West and Yorkshire have been identified as strongholds for the species (Buglife 2014). It is nearly always scarce, but it is possibly under-recorded because of its small size.
Tormentil Mining bee surveys and report 2022/23
A resurveys of the Tormentil mining bee Andrena tarsata sites in Yorkshire re-found the species at three key sites, Allerthorpe Common, Jugger Howe and Pampledale Moor. There were no records of Nomada roberjeotiana although some sites had historic records.
Monitoring has continued at the sites, plus two historic sites where we hope the species will be rediscovered. Numbers are highest at Allerthorpe, where grazing is absent, with lower numbers at the other two sites. Habitat management of flower-rich margin and sandy nesting sites benefits many other heathland invertebrate species.
Habitat management advice provided by SRT has seen scrub management to prevent loss of flower-rich margins on both Allerthorpe and Jugger Howe, plus creation of new nesting habitat at Allerthorpe Common. Additionally some grazing control on Jugger Howe, via temporary fencing. On Jugger Howe Tormentil growth where gorse was removed, has already had Tormentil mining bees recorded on it.
In 2023 we will be testing acoustic monitoring for this elusive species.