Cuckoo bumblebees

Bombus/Psithyrus rupestris, Red-tailed cuckoo bumblebee

Psithryus rupestris femalePsithryus rupestris male

She takes over the nests of Bombus lapidarius. Has darker wings than Lapidarius. Body lengths, female (above left) 22 mm, male (above right) 16 mm. Forewing lengths 19 mm female and 14 mm male. This is a very large bee with smoky dark wings. Females fly from May or June, and males and new females from July. The males form small mating swarms or leks to attract females on hillsides. Favourite flowers include dandelions, comfrey, oil-seed rape, thistles teasel, ragwort, brambles and scabious. It is found from the Midlands southwards, though it is rarer in Wales and the west. It has not been recorded from Scotland and is rare in Ireland.

Bombus/Psithyrus sylvestris, (Forest cuckoo bumblebee)

Psithryus sylvestris femalePsithryus sylvestris male

Common and takes over the nests of Bombus pratorum and jonellus. Body lengths, female (above left) 15 mm, male (above right) 14 mm. Forewing lengths, female 15 mm, male 13 mm. Male hair colour is very variable. Females can be seen as early as late March in the south, and males in April, therefore there would appear to be two generations in the south. In the north they are not normally seen until May. As their Latin name suggests they are found in wooded areas. Favourite flowers include, dandelion, nettles, bilberry, thistles, bramble and scabious. They are fairly common throughout Britain, but rare in the Channel Islands. Males tend to patrol mating circuits within 1 m off the ground. There are also reports of them lekking groups to attract females.

Bombus/Psithyrus bohemicus, Gypsy cuckoo bumblebee

Psithryus bohemicus femalePsithryus bohemicus male

Common and takes over the nests of Bombus lucorum. This is the commonest cuckoo in the Scottish highlands. Found in heathland, high meadows, and birch and pine woodland. Body lengths, female (above left) 19 mm, male (above right) 16 mm. Forewing lengths 16 mm female, 14 mm male. Females fly from April in the south and May in the north. Males and new females can be seen as early as June. Favourite flowers include dandelion, bilberry, thistles, brambles, heather, and scabious.

Bombus/Psithyrus vestalis, (Southern cuckoo bumblebee)

Psithryus vestalis femalePsithryus vestalis male

More common in the south, and not recorded in Scotland*. She takes over the nests of Bombus terrestris. Body lengths, female (above left) 21 mm, male (above right) 16 mm. Forewing lengths, female 18 mm, male 14 mm. Females fly from late March, and males from late May. Preferred flowers include sallows, blackthorn, cherry, dandelion, ivy, dead nettle, thistle, teasel, bramble and lavender.

*It has recently been confirmed that this bumblebee was found in southern Scotland in the summer of 2009.

Bombus/Psithyrus barbutellus, Barbut's cuckoo bumblebee

Psithryus barbutellus femaleBombus/Psithrus barbuellus male

Common and takes over the nests of Bombus hortorum and B. ruderatus. It is found mainly in England and sometimes in Wales, it is rare in Scotland and Ireland. Body lengths, female (above left) 18 mm, male (above right) 15 mm. Forewing lengths female 16 mm, male 13 mm.

Females are seen from April, males are most numerous during June and July, new females emerge from September.

Preferred flowers include, dead nettles, hawthorn, thistles, clovers, knapweed and Buddleia.

Bombus/Psithyrus campestris (Field cuckoo bumblebee)

Psithryus campestris female

Common and takes over the nests of Bombus pascuorum. Body lengths, female (above) 18 mm, male, light and dark forms below, 15 mm. Forewing lengths 15 mm female, 13 mm male. Females fly from April and males from June. There may be two generations of this species per year in the south. Favourite flowers include, ivy, dandelion, clovers, hawthorn, thistles, knapweeds, brambles and scabious. It is fairly common in England and Wales, rare in Scotland and Ireland.

Psithryus campestris male light formPsithryus campestris male dark form

Many of the images on this page were taken from Prys-Jones and Corbet's excellent book Bumblebees. As you can see the cuckoos resemble the species whose nests they take over.

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