#14 Tormentil Mining Bee by Vicky Wilkins
Meet Vicky Wilkins, Programme Manager at the Species Recovery Trust!
In her role at the Species Recovery Trust, Vicky leads invertebrate conservation projects in the North of England and overseas. Her current projects include the UK’s dazzlingly iridescent Tansy Beetle Chyrsolina graminis, as well as the threatened invertebrate endemics of the islands of St Helena, Ascension Island and Monserrat, which are all rich in incredible invertebrate species. She has always loved to champion the forgotten and overlooked species that are so integral to biodiversity. You can contact Vicky on vicky.wilkins@speciesrecoverytrust.org.uk, and find the Species Recovery Trust on twitter at @speciesrecovery and on Facebook.
Tormentil mining bee, Allerthorpe Common.
Vicky’s chosen species the tiny but beautiful Tormentil Mining Bee Andrena tarsata, one of the UK’s most elusive bees. Found on moorland and lowland heaths in Yorkshire, it is a specialist on the creeping perennial plant Tormentil which it uses to forage and provision its offspring. Yorkshire is one of its last remaining strongholds. This small, dark-coloured bee is less than a centimetre long, and it can be found on the wing in July when long summer days provide it with essential heat and dry weather conditions to breed. It is a tricky bee to identify with it being small and dark, but a combination of the distinctive translucent orange hind tibiae (lower parts of the back legs) and tarsi (part of the front legs) in contrast to the dark femur and a partially black-haired thorax with a fringe of grey hairs are distinctive in the females, and a combination of a pale clypeus (the broad plate at the front of the head), partly orange tarsi, and black hairs on the thorax identify male bees. It nests on the ground in small aggregations, selecting sheltered areas such as sandy banks (either flat or vertical) and bare ground.
Sandy, bare open ground that the Tormentil mining bee uses to nest.
It also has an associated nomad bee Nomada roberjeotiana, which is even more elusive than its host. This kleptoparasite bee targets the unsealed pollen-stocked nest cells of the Tormentil Mining Bee and sneakily lays their own eggs inside, destroying the host’s eggs and making use of its provisions.
The Tormentil Mining Bee is found across the UK in England, Wales and Scotland, with strongholds in Yorkshire and the South-West (Cornwall, Devon and Dorset). Although this bee is widespread, its numbers have been nose diving and it has been lost from 50% of its former sites since 1970, so its distribution is fragmented and localised (Bees, Wasps and Ants Recording Society data). It is nearly always scarce, but it is possibly under-recorded because of its small size. Unfortunately, in line with the national picture, records suggest that this species is continuing to contract its range in Yorkshire with sites slowly being lost. Nationally the Tormentil Mining Bee is a Section 41 species (a species of principal importance under the Natural Environment and Rural Communities Act, 2006).
This Species Recovery Trust project is monitoring the Tormentil Mining Bee’s 5 core sites in Yorkshire, where it is (or was) known to occur, in order to better understand its needs and status in the county. Results are already showing large differences between the sites, which include Jugger Howe (Flyingdales), Pampledale Moor (Cod Reservoir) and Allterthorpe Common - site management and the habitat characteristic formed through management are key to this species. In Yorkshire moor and heath sites, grassy edge habitats appear to be particularly important for this species, as they’re abundant with tall flower-rich food sources, including Tormentil. The presence of open sandy track edges and cliffs, which provide nesting sites for the bee to ‘mine’ into, are also essential.
Both sandy nesting areas and flower-rich, tall grassy ‘edge’ areas are important on heath and moorland sites for a wide range of specialist bees and other invertebrates beyond the Tormentil Mining Bee. However, these key microhabitats are increasingly at risk of being overlooked. For the flower-rich, tall grassy areas, this is often due to sheep grazing and scrubbing up. Even in low numbers, sheep can easily decimate a tall and floristically diverse grassy area. The uncontrolled encroachment of scrub also sees important bee foraging sites disappear. On the other hand, the sandy nesting areas are at risk of being compromised due to a lack of management, as they need a certain level of disturbance to keep them open to allow the bees to nest. Where these grassy and sandy areas do exist with the right balance of management, they are noisy, vibrant and vibrating with the buzz of hundreds of invertebrates. In light of the biodiversity crisis and declines in insects specifically, ensuring the presence of these important habitats becomes more vital than ever.
Monitoring
Tormentil, the specialist food plant of the Tormentil mining bee, at Jugger Howe.
Currently the monitoring for this species is mixed, and like many rare invertebrates is a big challenge. With a combination of the special training needed to allow identification, their low numbers, and their presence on the wing for only a month or two each year, often the ultimate goal is simply to confirm species presence rather than determine population estimates or other parameters. Currently, presence and absence monitoring are carried out an annual basis by visiting the site and undertaking extensive searches in the right type of habitat and in the right weather conditions. However, for the sites where the numbers are higher, such as Allerthorpe Common, timed transects can be used as a way of recording frequency to compare differences annually and between sites.
Further information and acknowledgements
NEYEDC would like to thank Vicky for her time and expertise in helping to create this blog. The project discussed above is a Species Recovery Trust project and was possible due to funding and generous support from the Michael Marks Charitable Trust and the Seven Pillars of Wisdom Charitable Trust. Vicky would like to thank all the landowners and managers for access, cooperation and support during this work. If you’d be interested in contributing a piece for the series, contact Lucy at lucy.baldwin@neyedc.co.uk. To find out more about biological recording, see the Naturalists page on our website.