One unique feature suggests a common ancestry and these features are used to define groups, such as families, in nature.
Andrenidae has two lines (sub-antennal sutures) between each antennal socket and the clypeus (main segment of lower face). Other bees all have one sub-antennal suture on each side. Andrena (sand bees) is a very common, diverse genus in the Northern Hemisphere but uncommon in South Africa where there is only one species. They look similar to honeybees and are hard to identify because they are very hairy making it difficult to see the subantennal sutures. But Melitturga (hovering shaggy bees) and Meliturgula (worm tongue shaggy bees) mostly have pale faces and the two subantennal sutures are easier to see.
Colletidae have a forked tongue that they use to paint a cellophane-like secretion onto their larval cell walls for waterproofing. Colletes (cellophane bees) are very hairy and their eyes converge below. Masked bees are almost naked and look like wasps, but their antennal sockets are in the middle of their faces.
In Scrapter (membrane bees) the eyes do not converge below. They are difficult to identify because some are hairy while others are almost naked, and they range in size from large to tiny. They only occur in South Africa, mostly in the eastern and western Cape provinces.
In Halictidae one particular vein in the forewing (basal vein) is curved. No other short-tongued bee has a curved basal vein, but in Ceratina, a long-tongued bee, this vein is sometimes slightly curved. Because this is one of the largest bee families I’ll deal with the halictid genera in the next article.
unfortunately, do not have a unique unifying feature. It is the most primitive family of bees. There are six genera that occur in South Africa. To identify them you’ll need to use the keys in The Bee Genera and Subgenera of sub-Saharan Africa http://www.abctaxa.be/
A large black and yellow bee (Meganomia, Desert buzzing bee) occurs in large numbers in sandy areas in the Kalahari and northern Limpopo. Unlike other Melittidae that visit only a few flower types, this bee visits many different types of flowers and adapts its pollen-collecting techniques accordingly. In Cleome (Cleomaceae) the anthers are attached to long filaments. Meganomia catches the filament with its mandibles and slides down to the anthers where it gathers pollen.
The other cool genus is Rediviva (Long legged oil bee) in which many of its species have extremely long forelegs. They visit the flowers of the oil-producing plant Diascia. Diascia has oil spurs of different lengths (depending on the species). The long-legged-oil-bees collects the oil between the hairs on their forelegs and the length of the bees forelegs coincides with the length of the spur of the Diascia flowers they visit.
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