The bee

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to confl ...

Ctenoplectrini of the subfamily

Apinae The Apinae are the subfamily that includes the majority of bees in the family Apidae. It includes the familiar " corbiculate" (pollen basket) bees—bumblebees, honey bees, orchid bees, stingless bees, Africanized bees, and the extinct genus ' ...

, with the two genera ''Ctenoplectra'' and ''Ctenoplectrina'', comprises 9 species in tropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, 10 in

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

, and 1 in Australia.

Description

The Ctenoplectrini are characterised by short tongues, modified

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, mos ...

e and large comb-like tibial spurs adapted to collect and carry a mixture of floral oils and pollen. The unusual morphology has made it difficult to infer their closest relatives, in turn preventing an understanding of these bees’ geographic and temporal origin and had led early authors to place them in their own family Ctenoplectridae. Recent molecular phylogenetic analyses find Ctenoplectrini to be monophyletic and closest to the long-horned bees, Eucerini. Most of the tribe's species collect floral oil, pollen, and nectar from a few genera of the family

Cucurbitaceae The Cucurbitaceae, also called cucurbits or the gourd family, are a plant family consisting of about 965 species in around 95 genera, of which the most important to humans are: *'' Cucurbita'' – squash, pumpkin, zucchini, some gourds *'' La ...

. However, three species are thought to be

kleptoparasite Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when f ...

Kleptoparasitic species

The presumably

kleptoparasitic Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when fo ...

species form a clade (''Ctenoplectrina'') that is sister to the remaining genus (''Ctenoplectra''), confirming the independent

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

kleptoparasitism Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when fo ...

in this tribe. Tree topology and molecular dating together suggest that Ctenoplectrini originated in

in the Early

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

and that ''Ctenoplectra'' dispersed twice from

, sometime in the Late

, 30–40 million years ago. From Asia one species reached the Australian continent via

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

and

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...

in the mid-

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

, ''circa'' 13 million years ago. Dry and cool mid-Miocene climates also coincide with the divergence between ''Ctenoplectra bequaerti'' from

West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mau ...

, and ''Ctenoplectra terminalis'' from

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the histori ...

and

Southern Africa Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number ...

, perhaps related to fragmentation of the equatorial

African rainforest Although tropical Africa is mostly familiar to the West for its rainforests, this biogeographic realm of Africa is far more diverse. While the tropics are thought of as regions with hot moist climates, which are caused by latitude and the tropi ...

belt. Nests are known from few species only, which use existing small holes in wood and stone or old nests of other bees, which they provision with a mixture of pollen and floral oil, exclusively gathered from plants of a few genera of the family

References

* Michener, C.D. (2000). ''The Bees of the World''. Johns Hopkins University Press. *Stefan Vogel (1990). "Ölblumen und ölsammelnde Bienen. Dritte Folge. Momordica, Thladiantha und die Ctenoplectridae". Trop. u. Subtrop. Pflanzenwelt 73:1-186. * Hanno Schaefer & S. S. Renner (2008). "A phylogeny of the oil bee tribe Ctenoplectrini (Hymenoptera: Anthophila) based on mitochondrial and nuclear data: Evidence for Early Eocene divergence and repeated out-of-Africa dispersal". Molecular phylogenetics and Evolution 47(2): 799–811. Apinae Bee tribes {{Apinae-stub