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Roca et al 2001

Roca et al 2001. Vilgalys 1994. http://botit.botany.wisc.edu/toms_fungi/oct98.html. Brown et al. 1999. Brown et al. 1999. Brown et al. 1999. Movement of Pacific plate. Decrease in Age of Island. http://atlas.geo.cornell.edu/education/instructor/topography/hawaii_seamounts.html.

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Roca et al 2001

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  1. Roca et al 2001

  2. Vilgalys 1994 http://botit.botany.wisc.edu/toms_fungi/oct98.html

  3. Brown et al. 1999

  4. Brown et al. 1999

  5. Brown et al. 1999

  6. Movement of Pacific plate Decrease in Age of Island http://atlas.geo.cornell.edu/education/instructor/topography/hawaii_seamounts.html

  7. Mendelson and Shaw 2005

  8. Distinquishing within- vs. between-island speciation using evolutionary trees Within-island speciation

  9. Distinquishing within- vs. between-island speciation using evolutionary trees Between-island speciation

  10. Geographic (island) distribution Parsimony reconstruction

  11. Host association in Trupanea arboreae Dubautia arborea Dubautia linearis Dubautia ciliolata Dubautia scabra Argyroxiphium kauense http://commons.wikimedia.org/wiki/Commons:Featured_picture_candidates/Image:Hawaii_Island_topographic_map-fr.svg

  12. Mechanisms of species formation • Darwin: geographic separation followed by gradual (slow) adaptation to different ecological circumstances eventually leads to reproductive isolation • Two alternatives allow rapid speciation: • FOOD: Speciation due to shifts in host -- without geographic isolation • SEX: Speciation due to divergent sexual selection - with brief geographic isolation

  13. Model of sympatric speciation via shifts to new host (FOOD) 2 2 1 2 Host shift 1 1 1 2 New population founded via shift to derived host 2 Populations on two hosts become reproductively isolated Population uses ancestral host 1

  14. Signatures of sympatric speciation via host/habitat shift(after Via 2001) • Sympatric overlap of host patches • Mating on the host causes reproductive isolation between races • Host phenology differs • Divergent selection on different hosts/habitats

  15. Goldenrod gallmaker -- Eurosta solidaginis – an example of speciation via host-plant shift Illustration from Abrahamson and Weis (1997) Photo:Warren Abrahamson

  16. Speciation via SEXual selection Upon recontact, populations reproductively isolated due ONLY to female preference Geographic barrier divides populations Female preference for male trait diverges due to genetic drift Females in ancestral populations prefer bluemales

  17. Signatures of speciation via sexual selection(after Panhuis et al. 2001) • Populations within species vary in sexually selected traits and associated preferences, resulting in partial pre-mating isolation • Closely related species differ markedly in mating signals and preferences, which constitute the primary barrier to gene exchange • Species differ in few other traits besides those involved in mate choice

  18. from Turgeon et al. 2005 North American Enallagma

  19. Turgeon et al. 2005

  20. Damselfly Mating Practices Photo: Denise Steele, Dartmouth College

  21. McPeek et al. (in press)

  22. Robertson and Paterson, 1982. Evolution.

  23. McPeek et al. (in press)

  24. McPeek et al. (in press) Shape evolution NS different from “punctuated evolution”

  25. Change in female shape correlated to change in male shape McPeek et al. 2009

  26. Brown, McPeek and May.2000 Syst. Biol. 49:697-712.

  27. Selection and the Enallagma radiation • Four damselfly-lake species generated by habitat shifts and adaptive evolution (morphological, behavioral and physiological) • Many fish-lake species generated during recent radiations (associated with glacial retreat?), possibly via founder effects on mechanical mate recognition system

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