Author
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LOVEJOY, N - UIVERSITY OF TORONTO, CAD |
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MULLEN, S - CORNELL UNIVERSITY, NY |
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Sword, Gregory |
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CHAPMAN, R - UNIVERSITY OF ARIZONA-TUC |
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HARRISON, R - UNIVESITY OF MARYLAND |
Submitted to: Proceedings of the Royal Society of London B
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/24/2005 Publication Date: 12/21/2005 Citation: Lovejoy, N.R., Mullen, S.P., Sword, G.A., Chapman, R.G., Harrison, R.G. 2005. Ancient trans-atlantic flight explains locust biogeography: Molecular phylogenetics of schistocerca. Proceedings of the Royal Society of London B. 273:767-774. Interpretive Summary: The desert locust (Schistocercagregaria) has been an important agricultural pest at least since biblical times. Although the ecology, physiology and behaviour of this insect species have been well characterized, its biogeographical origins and evolutionary history are more obscure. Schistocerca gregaria occurs throughout Africa, the Middle East and Western Asia, but all other species in the genus Schistocerca are found in the New World. Because S. gregaria has the capacity for extreme long-distance movement associated with swarming behaviour, dispersal may have played an important role in determining current distribution patterns. Some authors have argued that S. gregaria is the product of an eastward trans-Atlantic dispersal from North America to Africa; others consider it more likely that the New World taxa are the product of westward dispersal from Africa. Here, we present a mitochondrial DNA phylogeny of Schistocerca species that supports the monophyly of New World species (including the Galapago sendemic Halmenus) relative to S. gregaria. In concert with observed patterns of molecular divergence, and in contrast to previous morphological studies, our analysis indicates a single trans-Atlantic flight from Africa to South America, followed by extensive speciation and ecological divergence in the New World. Technical Abstract: The desert locust (Schistocercagregaria) has been an important agricultural pest at least since biblical times. Although the ecology, physiology and behaviour of this insect species have been well characterized, its biogeographical origins and evolutionary history are more obscure. Schistocerca gregaria occurs throughout Africa, the Middle East and Western Asia, but all other species in the genus Schistocerca are found in the New World. Because S. gregaria has the capacity for extreme long-distance movement associated with swarming behaviour, dispersal may have played an important role in determining current distribution patterns. Some authors have argued that S. gregaria is the product of an eastward trans-Atlantic dispersal from North America to Africa; others consider it more likely that the New World taxa are the product of westward dispersal from Africa. Here, we present a mitochondrial DNA phylogeny of Schistocerca species that supports the monophyly of New World species (including the Galapago sendemic Halmenus) relative to S. gregaria. In concert with observed patterns of molecular divergence, and in contrast to previous morphological studies, our analysis indicates a single trans-Atlantic flight from Africa to South America, followed by extensive speciation and ecological divergence in the New World. |