Three species of bumblebee in Ireland are virtually identical in appearance and workers cannot be reliably separated without the use of genetic  analysis. These are the White-tailed Bumblebee (Bombus lucorum), the Northern White-tailed Bumblebee (Bombus magnus) and the Cryptic Bumblebee (Bombus cryptarum). The queens and workers of all three species are black with a white tail and one lemon-yellow band on the thorax and one on the abdomen. The queens are separable in most cases. Compared to queens of  Bombus lucorum, Bombus magnus tends to possess a thicker yellow thoracic band, which extends further down the sides of the abdomen. Bombus cryptarum queen usually have a curved, somewhat ‘s’-shaped line of black hairs on the yellow band just in front of the wing bases, which requires close examination to see. Males can sometimes be identified also, with Bombus lucorum males possessing extensive yellow hairs on the head and thorax, including pale hairs interspersed with black hairs on the top of the thorax. Bombus magnus males have more sparse yellow hairs on the head and reduced yellow colouration on the thorax. The central area of black hairs on the thorax typically lacks any paler interspersed hairs. Bombus cryptarum males typically have dark hairs on the head and once again lack pale hairs in the central black-haired area on top of the thorax. The yellow band on the thorax also does not extend as far down the sides of the thorax comapared to the other two species. It should be noted that these charcteristics are variable and therefore not always reliable, so it is usually best to record them as ‘Bombus lucorum agg.’ if you are unsure.

Distribution in Ireland: B. lucorum is common and widespread, B. magnus is widely recorded but more so from western and upland areas, B. cryptarum has been recorded primarily from the southeast of the island, with a scattering of sightings from Ulster and 1 from Kerry.

Flight Period:  Late February/March-October for B. lucorum, April-September for B. magnus. Precise data for B. cryptarum is unavailable but probably similar.

Habitat: B. lucorum can be found in a wide range of habitats such as gardens, farmland, woodland clearings and edges, heath, unimproved grassland and brownfield sites. B. magnus reportedly favours upland areas, particularly heather-rich moorland and dry heath. Data for B. cryptarum would suggest upland areas are also favoured, but with a preference for pastures, meadows and woodland edges.

Flowers visited: In upland areas, Bell Heather and Ling appear to be important foraging resources. Elsewhere a wide range of flowers are favoured, such as brambles, thistles, scabiouses, knapweeds, clovers, Bird’s-foot Trefoil, willows, dandelions and many garden plants.

Personal Records: The confusion of this taxon means that I cannot say for sure where I have seen each individual species. Based on queens and males, I have reliably recorded true Bombus lucorum widely in counties Down, Antrim, Armagh, Donegal, Fermanagh, Monaghan, Louth, Cork, Wicklow, Carlow and Waterford.  I have recorded Bombus magnus in upland sites in the Mournes (Co. Down), the Cooleys (Co. Louth), Wicklow Mountains (Co. Wicklow) and various heathland sites in Co. Donegal.  The three species are believed to be hosts of the Gypsy Cuckoo Bumblebee (Bombus bohemicus).