[TABD] articulo sobre Ithomia
Keith Willmott
kwillmott at flmnh.ufl.edu
Tue Aug 22 16:51:49 BST 2006
Un nuevo articulo sobre Ithomia.
-------- Original Message --------
Subject: [HELICONIUS] Ithomia paper in "Evolution" journal
Date: Tue, 22 Aug 2006 16:47:08 +0100
From: Jim Mallet <j.mallet at ucl.ac.uk>
To: heliconius at ucl.ac.uk
Dear All,
I thought you might like to see this new paper in Evolution.
Available for download at:
http://heliconius.cap.ed.ac.uk/butterfly/publications/Jiggins_Evol2006.pdf
THE PHYLOGENETIC PATTERN OF SPECIATION AND WING PATTERN CHANGE IN
NEOTROPICAL ITHOMIA BUTTERFLIES (LEPIDOPTERA: NYMPHALIDAE), by Chris D.
Jiggins, Ricardo Mallarino, , Keith R. Willmott, Eldredge Bermingham
Species level phylogenetic hypotheses can be used to explore patterns of
divergence and speciation. In the tropics, speciation is commonly
attributed to either vicariance, perhaps within climate-induced forest
refugia, or ecological speciation caused by niche adaptation. Mimetic
butterflies have been used to identify forest refugia as well as in studies
of ecological speciation, so they are ideal for discriminating between
these two models. The genus Ithomia contains 24 species of warningly
colored mimetic butterflies found in South and Central America, and here we
use a phylogenetic hypothesis based on seven genes for 23 species to
investigate speciation in this group. The history of wing color pattern
evolution in the genus was reconstructed using both parsimony and
likelihood. The ancestral pattern for the group was almost certainly a
transparent butterfly, and there is strong evidence for convergent
evolution due to mimicry. A punctuationist model of pattern evolution was a
significantly better fit to the data than a gradualist model, demonstrating
that pattern changes above the species level were associated with
cladogenesis and supporting a model of ecological speciation driven by
mimicry adaptation. However, there was only one case of sister species
unambiguously differing in pattern, suggesting that some recent speciation
events have occurred without pattern shifts. The pattern of geographic
overlap between clades over time shows that closely related species are
mostly sympatric or, in one case, parapatric. This is consistent with modes
of speciation with ongoing gene flow, although rapid range changes
following allopatric speciation could give a similar pattern. Patterns of
lineage accumulation through time differed significantly from that expected
at random, and show that most of the extant species were present by the
beginning of the Pleistocene at the latest. Hence Pleistocene refugia are
unlikely to have played a major role in Ithomia diversification.
James Mallet
http://www.ucl.ac.uk/taxome/jim/
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--
Keith R. Willmott
Assistant Curator of Lepidoptera
McGuire Center for Lepidoptera and Biodiversity
Florida Museum of Natural History
University of Florida
SW 34th Street and Hull Road
PO Box 112710
Gainesville, FL 32611-2710 (USA)
Tel: (1 352) 846 2000 ext. 484
Fax: (1 352) 392 0479 or (1 352) 846 0253
Research:
http://www.flmnh.ufl.edu/butterflies/neotropica
Publications:
http://www.flmnh.ufl.edu/butterflies/neotropica/pubs.html
Butterflies of Ecuador:
http://www.butterfliesofecuador.com
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