Mason, Leafcutter, Carder, and Resin Bees

The Megachilidae is a cosmopolitan family of mostly solitary bees. One of their most distinctive features is that their pollen-carrying structure (called a scopa) is restricted to the ventral surface of the abdomen. They also typically have elongated labrum, which is what makes them unique from other bee families. Megachilid are most commonly known as Mason Bees and Leafcutter Bees due to the nature from which they build their nests (from either soil or leaves, respectively); a few collect plant or animal hairs and fibers and are called Carder Bees, while Resin Bees use plant resins in nest construction. All species feed on nectar and pollen, but some species are kleptoparasites (informally called “cuckoo bees”) and feed on pollen collected by other megachilid bees. These parasitic species do not possess scopae. The motion of Megachilidae in the reproductive structures of flowers is energetic, swimming-like; this agitation releases large amounts of pollen.

Mining Bees

The Andrenidae (commonly known as mining bees) are a large, nearly cosmopolitan family of solitary, ground-nesting bees. Most of the family’s diversity is located in temperate or arid areas.

The Andrenidae are typically small to moderate-sized bees, which often have scopae on the basal segments of the leg in addition to the tibia, and are commonly oligolectic (especially within the subfamily Panurginae). They can be separated from other bee families by the presence of two subantennal sutures on the face, a primitive trait shared with the sphecoid wasps. Many groups also have depressions or grooves called “foveae” on the head near the upper margin of the eyes, another feature seen in sphecoids, and also shared by some Colletidae. Andrenids are among the few bee families that have no cleptoparasites. The family contains a very large number of taxa, especially among the Panurginae, whose sting apparatus is so reduced that they are effectively unable to sting.[1]

Plasterer Bees

The Colletidae are a family of bees, and are often referred to collectively as plasterer bees or polyester bees, due to the method of smoothing the walls of their nest cells with secretions applied with their mouthparts; these secretions dry into a cellophane-like lining.[1] The five subfamilies, 54 genera, and over 2000 species are all (with the known exception of but one species, Amphylaeus morosus[2]) evidently solitary, though many nest in aggregations. Two of the subfamilies, Euryglossinae and Hylaeinae, lack the external pollen-carrying apparatus (the scopa) that otherwise characterizes most bees, and instead carry the pollen in their crops. These groups, and most genera in this family, have liquid or semiliquid pollen masses on which the larvae develop.

They can be found all over the world, but the most species live in South America and Australia. Over 50% of all bee species living in Australia belong to this family. Only the genera Colletes and Hylaeus can be found in Europe, while in North America, in addition to these two, the genera CaupolicanaEulonchopria, and Ptiloglossa are found.

Australian genera include Euhesma, a large genus, members of which has been split off into other genera such as Euryglossa and Callohesma.[3]

Traditionally, this family is believed to be likely the most “primitive” among extant bees, based primarily on the similarities of their mouthparts (the unique possession among bees of a bilobed glossa) to those of Crabronidae (the putative ancestors of bees), but recent molecular studies have disproved this hypothesis, placing the Melittidae (sensu lato) as the basal group of bees.

Melittid bees

Melittids are typically small to moderate-sized bees, which are well known for their specialist and oligolectic foraging habits.[1]

Melittids are strictly solitary and they nest in burrows that they dig in soil or sand.[9] All females can reproduce and tend to emerge from the ground some days before the male. They generally mate on host-plants surrounding the area they have emerged. After mating, the gravid female creates a burrow where they bring pollen. On top of the pollen, one egg is laid. This is consumed by the larva over 10 days, after which the larva overwinters and pupates in the next year.[1]

Many melittids (such as Macropis) possess specialized morphology that allow them to collect floral oil.

Swift and Comb-bearer Bees

The Stenotritidae is the smallest of all formally recognised bee families, with only 21 species in two genera, all of them restricted to Australia. Historically, they were generally considered to belong in the family Colletidae, but the stenotritids are presently considered their sister taxon, and deserving of family status.[1] Of prime importance is that the stenotritids have unmodified mouthparts, whereas colletids are separated from all other bees by having bilobed glossae.

The American entomologist Ronald J. McGinley proposed their position as an independent family based on the morphology of the glossae in 1980. [2] This view quickly became established.

They are large, densely hairy, fast-flying bees, which make simple burrows in the ground and firm, ovoid provision masses in cells lined with a waterproof secretion. The nests of some species can reach a depth of more than three metres.[3] The larvae do not spin cocoons.