Kathleen J. Craft a, Steffen U. Pauls b, Karolyn Darrow c, Scott E. Miller c, Paul D. N. Hebert d, Lauren E. Helgen c, Vojtech Novotny e, and George D. Weiblen a,1
-Author Affiliations
aDepartments of aPlant Biology and
bEntomology, University of Minnesota, Saint Paul, MN 55108;
cNational Museum of Natural History, Smithsonian Institution, Washington, DC 20013;
dBiodiversity Institute of Ontario, University of Guelph, Guelph, ON N1G 2W1, Canada; and
eInstitute of Entomology, Czech Academy of Sciences and Department of Zoology, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic
Communicated by Hans R. Herren, Millennium Institute, Arlington, VA, January 5, 2010 (received for review November 23, 2008)
Abstract
Comparative population genetics of ecological guilds can reveal generalities in patterns of differentiation bearing on hypotheses regarding the origin and maintenance of community diversity. Contradictory estimates of host specificity and beta diversity in tropical Lepidoptera (moths and butterflies) from New Guinea and the Americas have sparked debate on the role of host-associated divergence and geographic isolation in explaining latitudinal diversity gradients. We sampled haplotypes of mitochondrial cytochrome c oxidase I from 28 Lepidoptera species and 1,359 individuals across four host plant genera and eight sites in New Guinea to estimate population divergence in relation to host specificity and geography. Analyses of molecular variance and haplotype networks indicate varying patterns of genetic structure among ecologically similar sympatric species. One-quarter lacked evidence of isolation by distance or host-associated differentiation, whereas 21% exhibited both. Fourteen percent of the species exhibited host-associated differentiation without geographic isolation, 18% showed the opposite, and 21% were equivocal, insofar as analyses of molecular variance and haplotype networks yielded incongruent patterns. Variation in dietary breadth among community members suggests that speciation by specialization is an important, but not universal, mechanism for diversification of tropical Lepidoptera. Geographically widespread haplotypes challenge predictions of vicariance biogeography. Dispersal is important, and Lepidoptera communities appear to be highly dynamic according to the various phylogeographic histories of component species. Population genetic comparisons among herbivores of major tropical and temperate regions are needed to test predictions of ecological theory and evaluate global patterns of biodiversity.
Comparative population genetics of ecological guilds can reveal generalities in patterns of differentiation bearing on hypotheses regarding the origin and maintenance of community diversity. Contradictory estimates of host specificity and beta diversity in tropical Lepidoptera (moths and butterflies) from New Guinea and the Americas have sparked debate on the role of host-associated divergence and geographic isolation in explaining latitudinal diversity gradients. We sampled haplotypes of mitochondrial cytochrome c oxidase I from 28 Lepidoptera species and 1,359 individuals across four host plant genera and eight sites in New Guinea to estimate population divergence in relation to host specificity and geography. Analyses of molecular variance and haplotype networks indicate varying patterns of genetic structure among ecologically similar sympatric species. One-quarter lacked evidence of isolation by distance or host-associated differentiation, whereas 21% exhibited both. Fourteen percent of the species exhibited host-associated differentiation without geographic isolation, 18% showed the opposite, and 21% were equivocal, insofar as analyses of molecular variance and haplotype networks yielded incongruent patterns. Variation in dietary breadth among community members suggests that speciation by specialization is an important, but not universal, mechanism for diversification of tropical Lepidoptera. Geographically widespread haplotypes challenge predictions of vicariance biogeography. Dispersal is important, and Lepidoptera communities appear to be highly dynamic according to the various phylogeographic histories of component species. Population genetic comparisons among herbivores of major tropical and temperate regions are needed to test predictions of ecological theory and evaluate global patterns of biodiversity.
community ecology DNA barcoding phylogeography plant–insect interactions speciation
Footnotes
1To whom correspondence should be addressed. E-mail: gweiblen@umn.edu.
Author contributions: S.E.M., V.N., and G.D.W. designed research; K.J.C., S.U.P., K.D., S.E.M., V.N., and G.D.W. performed research; K.D., S.E.M., P.D.N.H., and L.E.H. contributed new reagents/analytic tools; K.J.C., S.U.P., and G.D.W. analyzed data; and K.J.C., S.U.P., and G.D.W. wrote the paper.
The authors declare no conflict of interest.
Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. FJ499817–FJ501172, GQ479199, GQ479200, GQ844279, and GQ844281–GQ844288).
This article contains supporting information online at www.pnas.org/cgi/content/full/0913084107/DCSupplemental.
The authors declare no conflict of interest.
Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. FJ499817–FJ501172, GQ479199, GQ479200, GQ844279, and GQ844281–GQ844288).
This article contains supporting information online at www.pnas.org/cgi/content/full/0913084107/DCSupplemental.
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