Global distribution patterns provide evidence of niche shift by the introduced African dung beetle Digitonthophagus gazella |
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| Authors: | Jorge Ari Noriega Kevin D Floate François Génier Chris AM Reid Bert Kohlmann Finbarr G Horgan Adrian LV Davis Shaun A Forgie Carlos Aguilar Mario G Ibarra Fernando Vaz-de-Mello Stefano Ziani Jorge M Lobo |
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| Institution: | 1. Department of Biogeography and Global Change, National Museum of Natural Sciences (CSIC), C/José Gutiérrez Abascal 2, Madrid, 28006 Spain;2. Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1 Canada;3. Canadian Museum of Nature, PO Box 3443, Station D, Ottawa, ON, K1P 6P4 Canada;4. Entomology & Arachnology, Australian Museum, 1 William Street, Sydney, NSW, 2010 Australia;5. EARTH University, San José, AP 4442-1000 Costa Rica;6. EcoLaVerna Integral Restoration Ecology, Bridestown, Kildinan, Co. Cork, Ireland;7. ScarabResearch Group, Department of Zoology & Entomology, University of Pretoria, P/B X20, Hatfield, 0028 South Africa;8. Landcare Research, Auckland, New Zealand;9. Museo Nacional de Historia Natural del Paraguay, San Lorenzo, Sucursal 1 Campus U.N.A., CDP: 2169, Central XI Paraguay;10. Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Av. Libertad, Corrientes, 5470 Argentina;11. Instituto de Biociencias, Departamento de Biologia e Zoologia, Universidade Federal de Mato Grosso, Boa Esperanza, Cuiba, MT, 78060-900 Brasil;12. GeoLab, Via Case di Dozza, Imola, BO, 22, 40026 Italy |
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| Abstract: | The establishment of cattle ranches throughout the world has prompted the release of dung beetles as biological control agents that reduce pasture fouling and control dung-breeding flies. One of these beetles, Digitonthophagus gazella (Fabricius) (Coleoptera: Scarabaeidae), that is native to southeast Africa, has been introduced into the Americas, Australia, and New Zealand. Distribution records for this species have been used to develop climate models of potential future establishment. Recent studies, however, identify D. gazella as a complex of seven species. Taking into account this revision, and the clear identification of the records belonging to the actual D. gazella, we developed environmental models to identify factors that have contributed to the establishment of this species across regions and habitats. We compared the environmental conditions of D. gazella in its native range against those in the regions where the species has or has not established. Our results indicate that D. gazella is still absent in certain parts of Central and South America and parts of Africa where it could potentially establish. We speculate that its distribution in Africa is limited by competitive exclusion. The introduction of D. gazella in America is relatively recent, such that the full extent of its distribution has probably yet to be realized. In Australia and North America, D. gazella is present in regions not predicted according to its native environmental conditions. This discrepancy may reflect a lack of competitive exclusion, phenotypic plasticity, and/or genetic adaptation. Our analyses suggest that the species has the ability to adapt to a wide range of environmental conditions that are extremely different from those in their native region. The species represents a useful case study to indicate that an introduced species may expand its realized niche beyond what is expected based on apparent environmental limits in the species native range. |
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| Keywords: | distribution model potential distribution colonization environmental niche invasive species Onthophagini Scarabaeinae Coleoptera Scarabaeidae biological control biocontrol agents species complex climate model pasture fouling dung-breeding flies |
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