Abstract
Weevils (Coleoptera: Curculionoidea) represent a remarkable proportion of global biodiversity, yet studies addressing their biogeography remain scarce. The arid parts of sub-Saharan Africa harbour several interesting weevil lineages, the most spectacular being the larger flightless weevils such as the Microcerinae and Brachycerus. Here we map the species richness of these two groups to identify hotspots in their diversity, and make inferences regarding the factors that may have contributed to the observed patterns. Exceptional richness values in both groups are found in southern Africa, and more specifically in the Nama Karoo, which is unremarkable in terms of plant diversity. By comparisons, plant diversity hotspots such as the Succulent Karoo and the Cape Floristic Region appear to have high, but not exceptional, weevil richness. Species richness levels were also high in the grassland and savanna areas of south-eastern Africa, which are not arid. The representation of genera considered here and their closest relatives, suggest an African origin for both lineages. This, combined with recent insights into weevil evolution, raise the possibility that advanced weevils as a whole (the family Curculionidae) originated in Africa and that some of its earliest offshoots survived and subsequently diversified here thanks to multiple factors, relating to climate and plant diversity alike.
References
Arzanov, Y.G. (2005) Review of weevils of the genus Brachycerus Olivier (Coleoptera: Brachy-ceridae) from the European part of Russia, the Caucasus and contiguous countries. Caucasian Entomological Bulletin, 1, 65−80.
Arzanov, Y.G. (2011) New species of genera Brachycerus Billberg, 1820 (Coleoptera: Brachyceridae) from Syria. Caucasian Entomological Bulletin, 7, 57−59.
Arzanov, Y.G. (2015) A revised checklist species of the Curculionoidea (Coleoptera, excluding Scolytinae) of Rostov Oblast and Kalmykia, the southern part of European Russia. Journal of Insect Biodiversity, 3, 1−32.
https://doi.org/10.12976/jib/2015.3.12Arzanov, Y.G. & Friedman, A. (2012) New species of Brachycerus Olivier (Coleoptera: Brachyceridae) from Turkey. Russian Entomological Journal, 21, 53–55.
Bologna, M.A., Audisio, P., Biondi, M. & Casale, A. (2008) The biogeographical patterns of disjunct distribution with special emphasis on the Mediterranean and southern African model. Biogeographia, 29, 7–17.
https://doi.org/10.21426/B6110011Born, J., Linder, H.P. & Desmet, P. (2007) The Greater Cape floristic region. Journal of Biogeography, 34, 147–162.
https://doi.org/10.1111/j.1365-2699.2006.01595.xCaldara, R., Colonnelli, E. & Osella, G. (2008) Curculionidae Curculioninae: relationships between Mediterranean and southern African species (Coleoptera). Biogeographia, 29, 133–156.
https://doi.org/10.21426/B6110062Colonnelli, E. (2004) Brachyceridae. In: Alonso-Zarazaga, M.A. (Ed.), Fauna Europea: Coleoptera: Curculionidae. Fauna Europaea version 1.0. Available from: http://www.faunaeur.org (accessed 22 August 2017)
Colonnelli, E. (2011) Brachyceridae. In: Löbl, I. & Smetana, A. (Eds.), Catalogue of Palearctic Coleoptera. Vol. 7. Curculionoidea 1. Apollo Books, Steenstrup, pp. 182–185.
Colonnelli, E. (2014) Apionidae, Nanophyidae, Brachyceridae and Curculionidae except Scolytinae (Coleoptera) from Socotra Island. Acta Entomologica Musei Nationalis Pragae, 54 (Supplement), pp. 295–422.
Cowling, R.M. & Hilton-Taylor, C. (1999) Plant biogeography, endemism and diversity In: Dean, W.R.J. & Milton, S. (Eds.), The Karoo. Ecological patterns and processes. Cambridge University Press, Cambridge, pp. 42–56.
https://doi.org/10.1017/CBO9780511541988.007Cowling, R.M., Procheş, Ş. & Vlok, J.H.J. (2005) On the origin of southern African subtropical thicket vegetation. South African Journal of Botany, 71, 1–23.
https://doi.org/10.1016/S0254-6299(15)30144-7Friedman, A. & Sagiv, A. (2010) Review of the genus Brachycerus Olivier in Israel (Coleoptera: Curculionoidea: Brachyceridae: Brachycerinae). Israel Journal of Entomology, 40, 25−70.
Gillett, C.P.D.T., Crampton-Platt, A., Timmermans, M.J.T.N., Jordal, B.H., Emerson, B.C. & Vogler, A.P. (2014) Bulk de novo mitogenome assembly from pooled total DNA elucidates the phylogeny of weevils (Coleoptera: Curculionoidea). Molecular Biology and Evolution, 31, 2223–2237.
https://doi.org/10.1093/molbev/msu154Haaf, E. (1957) Revision der äthiopischen und madagassischen Arten der Gattung Brachycerus Ol. (Col. Curc.). Entomologische Arbeiten aus dem Museum G. Frey, 8, 1−274.
Jansson, R. & Dynesius, M. (2002) The fate of clades in a world of recurrent climatic change: Milankovitch oscillations and evolution. Annual Reviews in Ecology, Evolution and Systematics, 33, 741–777.
https://doi.org/10.1146/annurev.ecolsys.33.010802.150520Leschen, R.A.B. & Beutel, R.G. (Eds.) (2014) Handbook of Zoology, Band 4: Arthropoda: Insecta, Teilband/Part 40: Coleoptera, Beetles. Vol. 3. Morphology and Systematics (Phytophaga). Walter de Gruyter, Berlin, 684 pp.
Louw, S. (1986) Revision of the Microcerinae (Coleoptera: Curculionidae) with an analysis of their phylogeny and zoogeography. Memoirs van die Nasionale Museum, Bloemfontein, 21, 1–331.
McKenna, D.D., Sequeira, A.S., Marvaldi, A.E. & Farrell, B.D. (2009) Temporal lags and overlap in the diversification of weevils and flowering plants. Proceedings of the National Academy of Sciences of the USA, 106, 7083−7088.
https://doi.org/10.1073/pnas.0810618106Meregalli, M. (2008) Niche shift: a tool for expanding range? The case of Ocladius (Coleoptera: Curculionoidea: Brachyceridae). Biogeographia, 29, 157–166.
https://doi.org/10.21426/B6110033Mucina, L. & Rutherford, M.C. (2006) The vegetation of South Africa, Lesotho and Swaziland. South African National Biodiversity Institute, Pretoria, 807 pp.
Myers, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B. & Kent, J. (2000) Biodiversity hotspots for conservation priorities. Nature, 403, 853–858.
https://doi.org/10.1038/35002501Oberprieler, R.G., Marvaldi, A.E. & Anderson, R.S. (2007) Weevils, weevils, weevils everywhere. Zootaxa, 1668, 491–520.
Olson, D.M., Dinerstein, E., Wikramanayake, E.D., Burgess, N.D., Powell, G.V., Underwood, E.C. & Kassem, K.R. (2001) Terrestrial ecoregions of the world: a new map of life on earth. BioScience, 51, 933−938.
https://doi.org/10.1641/0006-3568(2001)051[0933:TEOTWA]2.0.CO;2Osella, G., Colonnelli, E. & Zuppa, A.M. (1998) Mediterranean Curculionoidea with southern African affinities (Coleoptera). In: Colonnelli, E., Louw, S. & Osella, G. (Eds.), Taxonomy, ecology and distribution of Curculionoidea (Coleoptera: Polyphaga). Proceedings of a Symposium (28 August, 1996, Florence, Italy) XX International Congress of Entomology. Atti Museo Regionale di Scienze Naturali, Torino, pp. 221−265.
Prendini, L. (2005) Scorpion diversity and distribution in southern Africa: pattern and process In: Huber, B.A., Sinclair, B.J. & Lampe, K.H. (Eds.), African biodiversity: molecules, organisms, ecosystems. Springer, New York, pp. 25–68.
https://doi.org/10.1007/0-387-24320-8_2Procheş, Ş. (2003) Every plant has its weevil: Intimate relationships between weevils and plants in the Baviaanskloof. Veld & Flora, 89, 118−120.
Procheş, Ş. (2014) Relictual distributions in southern and East Africa: a “Khoisan fringe” in heelwalkers (Mantophasmatodea). North-western Journal of Zoology, 10, 300−304.
Procheş, Ş., Cowling, R.M., Goldblatt, P., Manning, J.C. & Snijman, D.A. (2006) An overview of the Cape geophytes. Biological Journal of the Linnean Society, 87, 27−43.
https://doi.org/10.1111/j.1095-8312.2006.00557.xProcheş, Ş. & Ramdhani, S. (2013) Eighty‐three lineages that took over the world: a first review of terrestrial cosmopolitan tetrapods. Journal of Biogeography, 40, 1819−1831.
https://doi.org/10.1111/jbi.12125Procheş, Ş., Ramdhani, S., Perera, S.J., Ali, J.R. & Gairola, S. (2015) Global hotspots in the present-day distribution of ancient animal and plant lineages. Scientific Reports, 5, 15457.
https://doi.org/10.1038/srep15457Valente, L.M., Savolainen, V., Manning, J.C., Goldblatt, P. & Vargas, P. (2011) Explaining disparities in species richness between Mediterranean floristic regions: a case study in Gladiolus (Iridaceae). Global Ecology and Biogeography, 20, 881–892.
https://doi.org/10.1111/j.1466-8238.2010.00644.x