Downland cannot hope to match heathland in the variety of mining bees foraging and/or breeding on the premises but there are some striking species to be found, especially on the flowers which thrive in this tough setting.
One of the most appealing, and a specialist on chalk or limestone soil, is Melitta haemorrhoidalis (13mm). One of four Melitta species in Britain, this is widely distributed but not common. Melitta haemorrhoidalis, which burrows into the soil for nesting in July and August, can be found wherever there are flowers from the Bellflower family. These include Clustered Bellflower, Harebell (Campanula rotundifolia) and, in gardens, Canterbury-bells (Campanula medium). From the same genus, Melitta leporina (12mm) is also found on chalk though sand is equally suitable providing there are clovers and vetches to be found since they are the only plants from which pollen is taken. Although widely distributed in southern Britain it is common only in the south-east and is becoming scarcer even there.
Various Osmia species breed on downland, notably those which use snail-shells as nest sites. Osmia bicolor (12mm) is one of these. The sight of a smallish bee on, say, a Roman snail shell is slightly incongruous but Osmia bicolor, which is evident from April to July, uses masticated leaves to build up to five cells inside before camouflaging the shell with grass or dead leaves - no easy task on that scale.
The scarcer Osmia aurulenta is of similar size to Osmia bicolor but is easily distinguished by the red hairs on the thorax though these can wear away. They, too, use snail shells for nesting, as does the very bonny Osmia spinulosa, a small (10mm) but robust bee which is widespread but local in southern Britain, restricted mainly to open calcareous grassland and coastal dunes. The females of all these Osmia species have red-orange hairs beneath the abdomen used for collecting pollen, which give them a tremendously dashing appearance.
Some Andrena bees are downland specialists, two of which show marked differences in colouring in the females. Both, perhaps coincidentally, perhaps not, use Scabious flowers exclusively for pollen collection. Andrena hattorfiana (14mm) is one of the largest British Andreninae and arguably the most attractive. Though still widespread in southern England it has declined substantially in the last 50 years, due probably to agricultural improvement, and is now very local. Designated as a Red Data Book species, its main, possibly only, pollen source is Field Scabious (Knautia arvensis) but it is sometimes seen at Small Scabious (Scabiosa columbaria). The red form of female is scarcer than the black in Britain, though not in parts of continental Europe, and they fly from late June to mid-August.
Another Scabious specialist, using also Devil's Bit Scabious (Succisa pratensis), is Andrena marginata, which is altogether smaller at 10mm and more delicate. They are a late bee, seen mostly in September. Males are uniformly dark though with a white face, but females range from the usual orange to dark brown and just about anything in between. This is shown in the accompanying images. Andrena marginata, which requires sunny, warm nest sites with short turf, is a scarce bee but not so scarce as its cleptoparasite, Nomada argentata (8mm), which is another Red Data Book species.
When fresh, the female shows the reason for the scientific name argentata since the silvery flashes of colouring on the abdomen are obvious. Sadly this species has been seen at only a handful of sites in the last 30 years, though it can do well in the locations where it is found.
Andrena rosae (13mm) is a fairly large and attractive species of mining bee that used to be present in lowland England but has declined dramatically and is Red Data Book 2 (vulnerable), found almost entirely in the West Country. Related to the spring species Andrena stragulata, they forage only from umbellifers including Wild Carrot that are commonplace on downland.
The mining bee Lasioglossum fulvicorne (10mm) is fairly common on calcareous grassland but much less evident on other soil types. The females have a long flight period from mid-March to late September and forage from various flowers. The species is parasitised by the two cuckoo bees, including Sphecodes hyalinatus (7mm).
Ceratina cyanea (Blue Carpenter Bee, 8mm) is one species which is doing well. This was first spotted in large numbers in Britain on Hampshire downland in 1972 but has since been found in heathland and woodland among other habitats. The species, whose blue is striking depending on the light, nests in stems, mostly Bramble but also Rose, and is regarded as scarce. The pictured male is lurking near a nest site in bramble.
The same piece of bramble also saw an appearance by the Red Data Book cuckoo bee Stelis ornatula (8mm). This bee is one of four from the Stelis genus in the UK, none of which is common, with three RDB and one scarce. Stelis ornatula is as versatile in habitat as Ceratina cyanea seems to be and uses Hoplitis claviventris (10mm) as its host.
The latter species, which nests in stems including bramble and Ragwort (Senecio jacobaea), is found in various habitats besides downland, notably broad-leaved woodland, heathland and the coast. The pictured female turned up in a garden not far from the North Downs in Surrey but also within easy reach of heath and forest.
The so-called Yellow-faced bees, some of which have ivory or white rather than yellow markings on the face, are found in a variety of habitats. However, the largest, Hylaeus signatus, (10mm) is closely associated with the flowers of Weld (Reseda luteola) and Wild Mignonette (Reseda lutea), the latter of which is especially common on downland. Almost any patch of these flowers seems to draw the bees in like a magnet. They fly from June to September.
Hylaeus cornutus (7mm) is the only member of the yellow-faced bee genus having an entirely black face, with no yellow markings, though the male has a lot of yellow on the antennae. The female used to be believed to be unique in carrying pollen back to the nest on the front of the face, where there are prongs either side, rather than in the crop. However, close observation of two females in my garden in 2016 showed that they did not carry much if any pollen in this manner. The species is scarce but found in many habitats, chiefly calcareous grassland but also on sand. An example of how the pollen/nectar mix is carried back is shown alongside with Hylaeus communis.
Images © Jeremy Early. All rights reserved.
In 2013 I published My Side of the Fence - the Natural History of a Surrey Garden. Details may be found, and orders placed, via this hyperlink My Side of the Fence. In November 2015 Surrey Wildlife Trust published the atlas Soldierflies, their allies and Conopidae of Surrey, jointly written by David Baldock and me. Details are on this web page: Atlas.