The bees highlighted in the North East Bee Hunt are some of the most easily identifiable in the field or from good photographs, mainly those of medium to large size. There are many smaller bees that are more challenging. Due to their size, they are often overlooked and under-recorded, and are often mistaken for flies.
I have chosen three genera that contain the smallest of our bees in the NE, the individuals being between 4-8mm from head to tail. These bees would require a specimen, microscope, and good key to get to exact species, but with the use of digital photography, we can now often separate them into their genera and even sub-groups.
Here I use scientific names for the species because this groups them by their shared characteristics, aiding identification, though I will mention common names for the genera. Many of these smaller species did not have common names until they were made up recently, so you will not find them referred to on websites, the internet or in books and keys. The scientific names do not vary from region to region.
Hylaeus species (Yellow-faced Bees)
Predominantly black solitary bees, not appearing hairy, usually with yellow or white facial markings, and easily mistaken for flies or solitary wasps. Females have a coloured pair of spots on the face, while males have predominantly pale-patterned faces, which makes them easy to sex, and sometimes, to identify from photos.
Of twelve species found in the UK, possibly 4 or 5 may nest in the NE, though there are very few records. The commonest of these appears to be Hylaeus communis (other possibles may be H. brevicornis, H. confusus, H. signatus, and in the west H. hyalinatus). They are on the wing between May and September.
Hylaeus bees nest in hollow plant stems and existing cavities in walls and wood. Nest cells are lined and sealed with a waterproof cellophane-like substance secreted in the bee’s mouth. Females carry pollen to the nest in the crop, along with nectar, so they have no pollen-collecting hairs. As they have short tongues they mostly forage on flowers with short corollas.
Lasioglossum morio group Bees (Base-banded Furrow Bees)
Lasioglossum and Halictus species are ground nesting bees that vary from the size of honeybees down to the smallest bees. The female’s tail (tergite 5) is always densely hairy with a bare-looking median furrow called the rima. In Lasioglossum, bands of white hair on the abdomen are located only at the base of each tergite (segment), while those in Halitus are on the apex. Females carry pollen on scopal hairs on their hind legs and visit a wide variety of flowers.
There are 34 species of Lasioglossum in the UK, of which 4 of the smallest are grouped together as the Lasioglossum morio group. The integument (skin) of the head and thorax are bright metallic bronze-green to blue-green (unlike other Lasioglossum which are non-metallic). There are records of 3 out of the 4 in the NE (L. leucopus, L. cupromicans, L. smeathmanellum), L. morio has so far not been recorded, though it is possibly here. The details required for identification are microscopic so species cannot be identified except under a microscope.
Most Lasioglossum nest underground in light soils, often in large aggregations, but this group also use decaying mortar. Females emerge in the spring and establish nests, often a vertical burrow with cells off it, the excavated soil forming a tumuli or spoil heap like mini-volcanoes round the entrance hole (other ground nesting bees such as Andrena also do this). They fly from April to September and are possibly host to the cleptoparasitic bee Sphecodes geofrellus.
Andrena are the largest genus of bees in the UK, with 70 species. The females have well-developed facial foveae, a band of short, dense, velvety hairs running parallel to the inside of the eyes, which is characteristic of this genus, though not always easy to see. Along with most ground nesting solitary bees, females carry pollen on scopal hairs on their hind legs, though in Andrena this is extensive and includes hairs on the propodeum. Most species have a black integument, but a few have red markings on the abdomen. In both sexes the forewing basal vein is straight, which separates them from Halictus and Lasioglossum, where the vein is strongly curved.
A sub-set of 10 Andrena species are referred to as mini-miners, of which only 2 are likely to be found in the NE, Andrena semilaevis and A. subopaca. The former shows a preference for umbellifers and speedwells, while the latter is the species most likely to be found in upland areas. Both species are host to the cleptoparasitic bee Nomada flavoguttata, and commonly effected by stylops (a parasite that lives within their body). Burrows can be vertical to horizontal with side shoots ending in one or more cells. A spoil heap of soil often accumulates as a tumulus around the entrance. They are on the wing between April and August.
By Louise Hislop, local naturalist
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