Northern Ireland's Priority Species

Sphecodes gibbus – a bee

 

Sphecodes gibbus (Linnaeus)
Family: Halictidae

The adults do not build and provision their own nest but instead lays its eggs in the nests of another species of solitary bee. The species can only survive where large populations of host bees are found.

In brief

  • A cuckoo bee, the females laying their eggs in the completed nest of another species of bee
  • The host species is one of the small bees in the genus Lasioglossum
  • Assess as Endangered in Ireland
  • Known from just one site in Northern Ireland

Species description
The bees in the genus Sphecodes are small to medium-sized insects with sparsely-haired bodies. The species are all superficially similar. The head, thorax and rear of the abdomen are black and the front half of the abdomen is red.

Life cycle
Bees are insects which construct nests which they provision with honey and nectar. They are some of the most fascinating of insects and, because of their role in pollination, some of the most important. The best known bees are the social species – honey and bumblebees – but most are non-social, solitary species. Each female solitary bee constructs and provisions an individual nest. There are also a large number of parasitic species, often called cuckoo bees. These species do not build a nest of their own but steal a constructed nest of another species. The females of the cuckoo bees enter the nests of their hosts when these are unguarded and lay an egg in one of the cells. The female cuckoo may remove the egg of the host, but in many species the host’s egg is destroyed by the larva of the cuckoo bee. The cuckoo larva then consumes the food stored in the cell. The adults of the cuckoo species will emerge the next season synchronously with the new generation of the host bees. Cuckoo bees do visit flowers but as they do not provision nests they do not possess any of the adaptations for transporting nectar and pollen.
The life cycle of S. gibbus in Ireland is poorly understood due to the lack of observations. The species is known to be a parasite of Halictus rubicundus which is one of the commonest of the Irish bees. The host species builds its nests in the ground.

Similar species
There are seven species of Sphecodes bee in Ireland. They all closely resemble each other and identification of the individual species requires close examination and expert knowledge.

How to see this species
This is a difficult species to see and field identification is not possible. In general parasitic species including species of Sphecodes are most likely to be seen in areas where there are large populations of the host bees. They can also be seen on flowers.

Current status
Known from only 2 Irish locations, Ballyteigue Burrows, Co.Wexford in August 1950 (where it has not been found since) and the Lagan Meadows, Co. Down in May 2004.

Why is this species a priority in Northern Ireland?
This is a threatened species in Ireland, assessed as Critically Endangered on the red list of Irish bees.

Threats/Causes of decline
The rarity of this bee makes it difficult to assess direct threats. The host bee is widespread in Ireland but any decline in its population will undoubtedly affect this species. All Irish bees are threatened by loss of nesting and foraging habitat.

Conservation of this species

Current action

  • Lagan Meadows are a local nature reserve and part of the Lagan Valley Regional Park

Proposed objectives/actions

  • Survey suitable sites to locate extant populations and, if any are found, ensure the population is maintained
  • Maintain suitable habitat for host species L. calceatum and L. albipes

What you can do
Discovering surviving populations of the bee is essential. There is also a need to gather Information on its habitat and ecology in Northern Ireland. This requires skilled observers and learning how to identify the species of Irish bee is a way you as an individual can make a valuable contribution. The decline of all species of bees should concern us as they are primary pollinators of many wild plants.

Further information

Links
National Biodiversity Data Centre

Bees, Wasps and Ants Recording Society

Photographs of Wild bees and wasps

Literature
Baldock, D. (2008). The Bees of Surrey. Surrey Wildlife Trust, Woking.

This is a good illustrated account of the bees of Surrey, which includes most of the Irish bees
Fitzpatrick Ú., Murray T.E., Byrne A., Paxton R.J. and Brown M.J.F. (2006). Regional Red List of Irish Bees, Report to National Parks and Wildlife Service (Ireland) and Environment and Heritage Service (N. Ireland).

Text written by:
Brian Nelson