Some of our work in Galapagos focuses on the early stages of adaptive radiation. Specifically, some populations of finches within a species have bimodal beak size distributions, with one mode composed of a small-beaked morph (left side of the photo) and the other of a large-beaked morph (right side of the photo). These two morphs have probably arisen because two different resources are available: hard seeds, for which large beaks are most appropriate, and soft seeds, for which small beaks are most appropriate. These sympatric beak-size morphs within species are thus a small-scale version of the differences among established species, suggesting that the morphs can be used to understand the early stages of adaptive radiation. Part of our work is focused on determining whether large- and small-beaked morphs do indeed specialize on different foods (i.e., divergent selection). We are also asking whether this adaptive split has led to assortative mating, reductions in gene flow, and the onset of speciation.
 
We have also found that a formerly bimodal population of finches has lost this property in concert with an increase in human population size at Academy Bay on Santa Cruz Island. This suggests that humans alter food resource distributions in ways that reverse the process of speciation and cause incipient species to fuse back together. We suggest that this change is the result of the introduction of plants and the feeding of finches, both of which may reduce selection against intermediate beak sizes. This improved fitness of intermediate forms thus breaks one of the barriers keeping different beak sizes as separate gene pools – in essence halting or reversing speciation.
 
Most recently, we are starting intensive effort to understand how finch evolution influences plant communities in Galapagos.

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Publications:
  1. Beausoleil, M.-O., P.L. Carrión, J. Podos, C. Camacho, J. Rabadán-González, R. Richard, K. Lalla, J.A.M. Raeymaekers, S.A. Knutie, L.F. De León, J.A. Chaves, D.H. Clayton, J.A.H. Koop, D.M.T. Sharpe, K.M. Gotanda, S.K. Huber, R.D.H. Barrett, and A.P. Hendry. 2023. The fitness landscape of a community of Darwin’s finches. Evolution 77:2533-2546. PDF
  2. Reyes-Corral, W.D., S. Carvajal-Endara, M. Hetherington-Rauth, J.A. Chaves, P.R. Grant, B.R. Grant, A.P. Hendry, and M.T.J. Johnson. In press. Phenotypic divergence of traits that mediate antagonistic and mutualistic interactions between island and continental populations of the tropical plant, Tribulus cistoides (Zygophyllaceae). Ecology and Evolution 13:e9766 PDF
  3. Carrión, P.L., J.A.M. Raeymaekers, L.F. De León, J. Chaves, D.M.T. Sharpe, S.K. Huber, A. Herrel, B. Vanhooydonck, K.M. Gotanda, J.A.H. Koop, S.A. Knutie, D.H. Clayton, J. Podos, and A.P. Hendry. 2022. The terroir of the finch: how spatial and temporal variation shapes phenotypic traits in Darwin’s finches. Ecology and Evolution 12:e9399. PDF​
  4. Beausoleil, M.-O., C. Camacho, J. Rabadán-González, K. Lalla, R. Richard, P. Carrion-Avilés, A.P. Hendry, and R.D.H. Barrett. 2022. Where did the finch go? Insights from radio telemetry of the medium ground finch (Geospiza fortis). Ecology and Evolution 12:e8768. PDF
  5. Carvajal-Endara, S., A.P. Hendry, N.C. Emery, C.P. Neu, D. Carmona, K.M. Gotanda, T.J. Davies, J.A. Chaves, and M.T.J. Johnson. 2020. The ecology and evolution of seed predation by Darwin’s finches on Tribulus cistoides in the Galápagos Islands. Ecological Monographs 90:e01392. PDF
  6. Beausoleil, M.-O., L.O. Frishkoff, L.K. M’Gonigle, J.A.M. Raeymaekers, S.A. Knutie, L.F. De León, S.K. Huber, J.A. Chaves, D.H. Clayton, J.A.H. Koop, J. Podos, D. Sharpe, A.P. Hendry, and R.D.H. Barrett. 2019. Temporally varying disruptive selection in the medium ground finch (Geospiza fortis). Proceedings of the Royal Society B. Biological Sciences 286:20192290. PDF
  7. De León, L.F., D.M.T. Sharpe, K.M. Gotanda, J.A.M. Raeymaekers, J.A. Chaves, A.P. Hendry, and J. Podos. 2019. Urbanization erodes niche segregation in Darwin’s finches. Evolutionary Applications 12:1329-1343. PDF
  8. Carvajal-Endara, S., A.P. Hendry, N. Emery, and T.J. Davies. 2017. Habitat filtering not dispersal limitation shapes oceanic island floras: species assembly of the Galápagos archipelago. Ecology Letters 20:495-504. PDF
  9. Chaves, J.A., E.A. Cooper, A.P. Hendry, J. Podos, L.F. De León, J.A.M. Raeymaekers, W. O. McMillan, and J. A. C. Uy. 2016. Genomic variation at the tips of the adaptive radiation of Darwin’s finches. Molecular Ecology 25:5282-5295. PDF
  10. De León, L. F., J. Podos, T. Gardezi, A. Herrel, and A.P. Hendry. 2014. Darwin’s finches and their diet niches: the sympatric co-existence of imperfect generalists. Journal of Evolutionary Biology 27:1093-1104.PDF
  11. De León, L. F., G. Rolshausen, E. Bermingham, J. Podos, and A. P. Hendry. 2012. Individual specialization and the seeds of adaptive radiation in Darwin’s finches. Evolutionary Ecology Research 14:365-380. PDF
  12. De León, L.F., J.A.M. Raeymaekers, E. Bermingham, J. Podos, A. Herrel, and A.P. Hendry. 2011. Exploring possible human influences on the evolution of Darwin’s finches. Evolution 65:2258-2272. PDF
  13. De León, L.F., E. Bermingham, J. Podos, and A.P. Hendry. 2010. Divergence with gene flow as facilitated by ecological differences: within-island variation in Darwin’s finches. Philosophical Transactions of the Royal Society. B. Biological Sciences 365:1041–1052. PDF
  14. Hendry, A.P., S.K. Huber, L. De León, A. Herrel, and J. Podos. 2009. Disruptive selection in a bimodal population of Darwin’s finches. Proceedings of the Royal Society B. Biological Sciences 276:753-759. PDF
  15. Herrel, A., J. Podos, B. Vanhooydonck, and A.P. Hendry. 2009. Force-velocity trade-off in Darwin’s finch jaw function: a biomechanical basis for ecological speciation? Functional Ecology 23:119-125. PDF
  16. Foster, D., J. Podos, and A.P. Hendry. 2008. A geometric morphometric appraisal of beak shape in Darwin’s finches. Journal of Evolutionary Biology 21:263-275. PDF
  17. Huber, S.K., L.F. De Leon, A.P. Hendry, E. Bermingham, and J. Podos. 2007. Reproductive isolation of sympatric morphs in a population of Darwin’s finches. Proceedings of the Royal Society B. Biological Sciences 274:1709-1714. PDF
  18. Hendry, A.P., P.R. Grant, B.R. Grant, H.A. Ford, M.J. Brewer, and J. Podos. 2006. Possible human impacts on adaptive radiation: beak size bimodality in Darwin’s finches. Proceedings of the Royal Society B. Biological Sciences. 273:1887-1894. PDF.
  19. Herrell, J. Podos, S.K. Huber, and A.P. Hendry. 2005. Evolution of bite force in Darwin’s finches: a key role for head width. Journal of Evolutionary Biology 18:669-675. PDF
  20. Herrel, A., J. Podos, S.K. Huber, and A.P. Hendry. 2005. Bite performance and morphology in a population of Darwin’s finches: implications for the evolution of beak shape. Functional Ecology. 19:43-48. PDF