Northern Ireland's Priority Species

Lasioglossum rufitarse – a solitary bee


Lasioglossum rufitarse (Zetterstedt)
Family: Halictidae

A small solitary bee with a black body with bands of flattened white hairs on the abdomen. It was discovered in Northern Ireland for the first time in 1985 on the north Antrim coast and there have been just a few Irish records.

In brief

  • This is a species of solitary bee, meaning that a female constructs and provisions a single nest

  • Its habitat requirements are not well understood, but the Northern Ireland specimens were taken beside a dry bank by a small stream in coastal grassland on the north Antrim coast

  • Females construct and provision a nest in early summer. The new generation of adults emerges later in the year, but only mated females survive the winter

  • The species has been reported foraging on flowers of bramble and ragwort

  • It is a rare species, restricted apparently to just a single site in Northern Ireland and rare elsewhere in Ireland

  • The European distribution of this species is unusual as it is more northern than related species

  • In North America, Lasioglossum bees are called sweat bees because of their liking for human perspiration

  • This species is possibly threatened by loss of habitat.

Species description
This is a small bee, about 7 or 8mm in length. The body is sparsely hairy, black and rather shiny. The abdomen is black with narrow bands of white hairs. The tarsi are covered in golden hairs. Identification of this species is not possible in the field.

Life cycle
Solitary bees have an annual life cycle. Mated females overwinter and construct a nest in late spring and early summer. The nests are provisioned with nectar and pollen. The new generation of adults emerges in late summer and these mate. The males die and the females enter hibernation. As far as is known, this species is a solitary species with each female constructing a single nest. Other species can vary the nesting strategy to a behaviour in which a female and her daughters cooperate to construct a single nest. However, this behaviour is not known in this species

Similar species
There are many species of solitary bee in Ireland and their identification is a specialist activity. There are eleven representatives of the genus Lasioglossum in Ireland. The species are all similar in appearance and their field identification is not possible.

How to see this species
This cannot be found without specialist knowledge. Nest aggregations of solitary bees can be large and conspicuous and be used by many species. Other species nest inconspicuously in small groups. In Ireland, nesting sites are limited by soil conditions and the best areas to see them are on coastal dunes and heaths with sunny, warm banks of well-drained soils. Nests of this species have been reported from banks of small streams, the exposed root plates of wind-blown trees and cliffs.

Current status
It has only been recorded once in Northern Ireland at White Park Bay on the North Antrim coast in 1985. Elsewhere in Ireland it is known from north Donegal, and two sites in Leinster.

Why is this species a priority in Northern Ireland?

  • The species is rare in Northern Ireland, restricted to a single site.

The Irish population also appears small.

Threats/Causes of decline
The species is possibly threatened by loss of habitat. Areas of bare ground are essential for nesting and this is probably a significant limiting factor. Nest sites can be destroyed easily, but equally they can be created by disturbance. Loss of forage plants is also potentially a threat, as they must be in close proximity to nest sites.

Conservation of this species

Current action

  • White Park Bay is designated as an ASSI and is part of the North Antrim coast SAC

  • It is a National Trust site.

Proposed objectives/actions

  • Survey suitable sites to locate extant populations and, if any are found, ensure the population is maintained.

What you can do
If you see the species, report any sightings to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU, Tel: 028 9039 5256, [at] or to the Bees, Wasps and Ants Recording Scheme (BWARS) who organise the recording of solitary bees in Britain and Ireland.

Further information



The National Trust

Nelson, B., Ronayne, C., Nash, R. and O’Connor, J.P. (2001). Additions and changes to the Irish aculeate Hymenoptera checklist. Irish Naturalists’ Journal 26: 453-459

Text written by:
Dr Brian Nelson, Curator of Freshwater Invertebrates, Ulster Museum