The Centridini are a tribe of large apid bees, many of which possess adaptations for carrying floral oils rather than (or in addition to)

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

. The floral oils are often gathered from plants of the family

Malpighiaceae Malpighiaceae is a family of flowering plants in the order Malpighiales. It comprises about 73 genera and 1315 species, all of which are native to the tropics and subtropics. About 80% of the genera and 90% of the species occur in the New World ( ...

, though other plants may be visited. The oil-collecting species typically have "combs" composed of closely spaced, flattened, blunt bristles on the margins of the first tarsal segments of the front and middle legs; others may have velvety "pads" to absorb the oils. They also commonly gather plant

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...

s for use in nest cell construction. They have a tiny

pterostigma The pterostigma (plural: pterostigmata) is a group of specialized cells in the outer insect wing, wings of insects, which are often thickened or coloured, and thus stand out from other cells. It is particularly noticeable in dragonfly, dragonfli ...

in the forewing, the female

scopa ''Scopa'' (; literally "broom") is an Italian card game, and one of the three major national card games in Italy, the others being ''Briscola'' and ''Tresette''. It is also popular in Argentina and Brazil, brought in by Italian immigrants, mostly ...

is very bushy, and the first

flagellomere Antennae ( antenna), sometimes referred to as "feelers", are paired appendages used for sensing in arthropods. Antennae are connected to the first one or two segments of the arthropod head. They vary widely in form but are always made of one o ...

of the antenna is often longer than the scape. ''

Centris The genus ''Centris'' contains circa 250 species of large apid bees occurring in the Neotropical and Nearctic realms, from Kansas to Argentina. Most females of these bees possess adaptations for carrying floral oils rather than (or in addition ...

'' are commonly encountered bees in American deserts, and are active at very high ambient temperatures when many other species are in hiding. They can often be seen in large numbers on palo verde blossoms. A common example in Arizona is ''

Centris pallida ''Centris pallida'' is a species of solitary bee native to North America. It lacks an accepted common name; however, it has been called the digger bee, the desert bee, and the pallid bee due to its actions, habitat, and color respectively. The s ...

''.

References

* C. D. Michener (2000) ''The Bees of the World'', Johns Hopkins University Press. Apinae Bee tribes {{Apinae-stub