Andrena bicolor Fabricius, 1775

Synonyms

Andrena picicornis (Kirby, 1802); Andrena pilosula (Kirby, 1802); Andrena gwynana (Kirby, 1802); Andrena proxima Smith, 1847; Andrena aestiva Smith, 1849; Andrena consimilis Smith, 1849.

Description and notes

Distribution

Throughout much of the British Isles, though mainly coastal in Scotland and Ireland. It is also known from the Isle of Man and the Channel Islands. Very widely distributed in the western Palaearctic, from Fennoscandia south to Iberia and Corsica, and east to Siberia. It has also been reported from North Africa, Israel and Iran.

Status (in Britain only)

This species is not considered to be threatened.

Habitat

Very catholic in its choice of habitats, occurring for example in open woodland and on calcareous grassland.

Flight period

Bivoltine, the first brood flying from early March to May or June, the second brood from June to late August. Specimens of the first brood are usually locally abundant. However, second brood specimens are far less common and, indeed, males of this brood tend to be extremely elusive.

Pollen collected

Polylectic. The first brood forages from barren strawberry (Potentilla sterilis), bluebell (Hyacinthoides non-scripa), butterbur (Petasites hybridus), buttercup (Ranunculus sp.), daffodil (Narcissus  sp.), daisy (Bellis perennis), dandelion (Taraxacum officinale), germander speedwell (Veronica chamaedrys), hawthorn (Crataegus monogyna), marsh-marigold (Caltha palustris), mustard (Brassica sp.), primrose (Primula vulgaris) and willow (Salix sp.). The summer brood has been confirmed as foraging from bramble (Rubus sp.), buttercup, cat's-ear (Hypochaeris radicata), cinquefoil (Potentilla sp.), crane's-bill (Geranium sp.), knapweed (Centauria sp.), lime (Tilia sp.), meadowsweet (Filipendula ulmaria), mustard, rose (Rosa sp.), thistle (Cirsium sp.) and willowherb (Epilobium sp.). These pollen sources were identified by pollen samples taken from female bees (Chambers, 1968).

Nesting biology

Nest burrows are rarely encountered and, in parts of Germany and eastern Europe, the species nests solitarily (Kocourek, 1966; Westrich, 1989). Brood cells have been located at the extreme depth of 101 cm (Malyshev, 1936).

Flowers visited

See above forage species. Females of the second brood are strongly associated with bellflowers (Campanulaceae), particularly harebell (Campanula rotundifolia) and clustered bellflower (Campanula glomerata) (pers. obs.).

Parasites

The species is a host of the cleptoparasite Nomada fabriciana (Linnaeus) (Perkins, 1919, 1924a, 1924b; Hallett, 1928, 1956; Spooner, 1931; Yarrow, 1941; Chambers, 1949; Westrich 1989). Specimens are occasionally stylopized, possibly by Stylops gwynanae, as in eastern Europe and Spain (Noskiewicz & Poluszynski, 1928).

Author of profile

G R Else.

Year profile last updated

2006