Distribution

South Africa.

Biology

Females are morphologically adapted to collect oil from a variety of oil-producing flowers (Iridaceae, Orchidaceae and Scrophulariaceae, Stilbaceae) in particular Diascia species (Scrophulariaceae) (Manning & Brothers 1986, Whitehead & Steiner 2001, Manning & Goldblatt 2002, Pauw 2006, Pauw et al. 2017, Whitehead et al. 2008). Flowers of Diascia species have twin spurs, which in some species are extremely elongated. Females of Rediviva species collect oil from the bottom of the spur by simultaneously inserting their elongate forelegs into each of the two spur tubes in the process pollinating the flower. The position of the anthers between the spurs ensures direct contact of pollen with the visiting bee's body. The pollen that adheres to her body makes contact with the stigma when she visits the next flower, ensuring effective cross-pollination. The oil is extracted with the aid of specialized hairs on the legs and transferred to the back legs for transport to the nest. The collected oil is mixed with pollen and this mixture is used as a food provision for her larvae, which develop in an underground nest.  Based on the correlation between spur and leg length co-evolution of the two partners as been hypothesised (Steiner & Whitehead 1990, 1991). 80% of evolutionary change in leg length was explained by adaption to the selective environment imposed by long-spurred, oil-secreting flowers i.e. long legs have largely evolved in oil-collecting Rediviva bees as a response to this selection pressure (Pauw et al 2017). These bees also have generalized pollen collecting habits (Kuhlmann & Eardley 2012) and are ground nesters (Kuhlmann, 2012).

References

Brothers D.J. 1999. Phylogeny and evolution of wasps, ants and bees (Hymenoptera, Chrysidoidea, Vespoidea and Apoidea) Zoologica Scripta 28: 233–250.

Cockerell, T.D.A. 1934. Descriptions and records of bees.—CXLVIII. Annals and Magazine of Natural History, (ser. 10) 13: 444–456.

Eardley, C & Urban, R. 2010. Catalogue of Afrotropical bees (Hymenoptera: Apoidea: Apiformes). Zootaxa 2455: 1-548.

Eardley, C, Finnamore, A.T. & Michener, C.D. 1993. Superfamily Apoidea (pp. 279-357). In GOULET, H. & HUBER, J. (eds). Hymenoptera of the World: an identification guide to families. Research Branch, Agriculture Canada, Ottawa, Canada, 668 pp.

Friese, H. 1909. 8. Hymenoptera. 5. Apidae. In: Sjoestedts, B.Y. (Ed.) Kilimandjaro-Meru Expedition. Stockholm, 8: pp. 119–168.

Friese, H. 1915. Zur Bienenfauna von Abessinien. (Hym.). Deutsche Entomologische Zeitschrift, 1915: 265–298.

Kuhlmann, M. 2009. Patterns of diversity, endemism and distribution of bees (Insecta: Hymenoptera: Anthophila) in southern Africa. South African Journal of Botany, 75: 726–738.

Kuhlmann, M. 2012. Two new species of the South African endemic bee genus Rediviva Friese (Hymenoptera: Apoidea: Melittidae). Zootaxa 3517: 71–78.

Kuhlmann, M. & Eardley, C.D. 2012. Pollen resources of non-Apis bees in southern Africa. In: Patiny, S. (Ed.) Evolution of plant-pollinator relationships. Oxford University Press, Cambridge, pp. 439–456.

Manning, J. C. & Brothers, D.J. 1986. Floral relations of for species of Rediviva in Natal (Hymenoptera: Apoidea: Melittidae). Journal of the Entomological Society of Southern Africa, 49: 107–114.

Manning, J. & Goldblatt, P. 2002. The pollination of Tritoniopsis parviflora (Iridaceae) by the oil-collecting bee Rediviva gigas (Hymenoptera: Melittidae): the first record of oil-secretion in African Iridaceae. South African Journal of Botany, 87: 171–176.

Michener, C.D. 1981. Classification of the bee family Melittidae with a review of species of Meganomiinae. Contributions of the American Entomological Institute, 18: 1–135.

Michener, C.D. 2007. The Bees of the World. Johns Hopkins University Press, Baltimore, Maryland, 992 pp.

Michez, D., Patiny, S. & Danforth, B.N. 2009. Phylogeny of the bee family Melittidae (Hymenoptera: Anthophila) based on combined molecular and morphological data. Systematic Entomology, 34: 574–597.

Pauw, A. 2006. Floral syndromes accurately predict pollination by a specialized oil-collecting bee (Rediviva peringueyi, Melittidae) in a guild of South African orchids (Coryciinae). American Journal of Botany, 93: 917–926.

Pauw A, Kahnt B, Kuhlmann M, Michez D, Montgomery GA, Murray E, Danforth BN. 2017. Long-legged bees make adaptive leaps: linking adaptation to coevolution in a plant–pollinator network. Proceedings of the Royal Society B 284: 20171707.
http://dx.doi.org/10.1098/rspb.2017.1707

Robertson, H.G. & Cochrane, M.A. 2005. Obituary - Vincent Booth Whitehead (2 September 1921–11 April 2005). African Entomology, 13: 386–389.

Steiner, K.E. & Whitehead, V.B. 1990. Pollinator adaptation to oil-secreting flowers–Rediviva and Diascia. Evolution, 44: 1701–1707. doi:10.1111/j.1558-5646.1990.tb03857.x

Steiner, K.E. & Whitehead, V.B. 1991. Oil flowers and oil bees: further evidence for pollinator adaptation. Evolution, 45: 1493–1501. doi:10.1111/j.1558-5646.1991.tb02651.x

Vogel, S., & Michener, C. D. 1985. Long bee legs and oil-producing floral spurs, and a new Rediviva (Hymenoptera, Melittidae; Scrophulariaceae). Journal of the Kansas Entomological Society 58: 359-364.

Whitehead, V.B. & Steiner, K.E. 2001. Oil-collecting bees of the winter rainfall area of South Africa (Melittidae, Rediviva). Annals of the South African Museum, 108: 143–277.

Whitehead, V.B., Steiner, K.E. & Eardley, C.D. 2008. Oil-collecting bees mostly of the summer rainfall area of southern Africa (Hymenoptera: Melittidae: Rediviva). Journal of the Kansas Entomological Society, 81: 122–141.

Credits

Photographs © Michael Kuhlmann (Natural History Museum London) or  © Simon van Noort (Iziko Museums of South Africa).

Map illustration © Simon van Noort (Iziko Museums of South Africa).