| Ceratina Temporal range: | |
|---|---|
 | |
| Ceratina bifida | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Apidae |
| Tribe: | Ceratinini |
| Genus: | Ceratina Latreille, 1802 |
| Species | |
>200 species | |
The cosmopolitan bee genus Ceratina, often referred to as small carpenter bees, [1] is the sole lineage of the tribe Ceratinini, and is not closely related to the more familiar carpenter bees. The genus presently contains over 300 species in 23 subgenera. [2] They make nests in dead wood, stems, or pith, and while many are solitary, a number are subsocial, with mothers caring for their larvae, and in a few cases where multiple females are found in a single nest, daughters or sisters may form very small, weakly eusocial colonies (where one bee forages and the other remains in the nest and lays eggs). One species is unique for having both social and asocial populations, Ceratina australensis , which exhibits all of the pre-adaptations for successful group living. This species is socially polymorphic with both solitary and social nests collected in sympatry. Social colonies in that species consist of two foundresses, one contributing both foraging and reproductive effort and the second which remains at the nest as a passive guard. Cooperative nesting provides no overt reproductive benefits over solitary nesting in this population, although brood survival tends to be greater in social colonies. Maternal longevity, subsociality and bivoltine nesting phenology in this species favour colony formation, while dispersal habits and offspring longevity may inhibit more frequent social nesting in this and other ceratinines. [3]
Contents
Ceratina are commonly dark, shining, even metallic bees, with fairly sparse body hairs and a weak scopa on the hind tibia. Most species have some yellow markings, most often restricted to the face, but often elsewhere on the body. They are very commonly mistaken for "sweat bees" (family Halictidae), due to their small size, metallic coloration, and some similarity in wing venation; they can be easily separated from halictids by the mouthparts (with a long glossa) and the hindwings (with a tiny jugal lobe). [4]
In Ceratina nigrolabiata , a Mediterranean species, males may guard the opening to the nest of a female they hope to mate with, and are often not the father of the brood within the nest; this is the first bee species in which male nest-guarding has been classified as a form of biparental care, [5] but males guarding nests and mating with females has been documented in other species (e.g., Macrotera portalis [6] ).
A few species of Ceratina are exceptional among bees in that they are parthenogenetic, reproducing without males. [7]
