About Darren Irwin

I am a Professor in the Department of Zoology, and the Biodiversity Research Centre, at the University of British Columbia.

“Ring Species” review published by Darren Irwin and David Wake


We wrote this review as an invited contribution to the Encyclopedia of Evolutionary Biology. The full citation:

Irwin, D.E., and D.B. Wake. 2016. Ring species. Vol. 3, Pages 467-475 in Encyclopedia of Evolutionary Biology, edited by R. M. Kliman. Oxford: Academic Press.

To read, you have three options (I recommend number 3):

  1. Purchase the article from Science Direct for $31.50:    http://www.sciencedirect.com/science/article/pii/B9780128000496000779
  2. Purchase the Encyclopedia from Elsevier for only $1,260.00    😉    http://store.elsevier.com/product.jsp?isbn=9780128000496
  3. Email me a request to send you the PDF, and I will gladly do so.

The Abstract:
A ring species is a ring of populations in which there is only a single species boundary. Two contacting forms behave as distinct species yet are connected by a long chain of populations through which there is gradual or stepwise change. Such situations provide an illustration of how the process of speciation, by which one species splits into two, can occur. Ring species are rare, but two cases provide good examples of how ring species can teach us about speciation: greenish warblers and Ensatina salamanders.

Kira Delmore publishes Proc B paper on migration and speciation


Congrats to Kira, Haley, and Ryan on a nice paper!

Delmore, K.E., L. Kenyon, R.R. Germain, and D.E. Irwin. 2015. Phenotypic divergence during speciation is inversely associated with differences in seasonal migration. Proceedings of the Royal Society of London B 282: 20151921. Link

Abstract:  Differences in seasonal migration might promote reproductive isolation and differentiation by causing populations in migratory divides to arrive on the breeding grounds at different times and/or produce hybrids that take inferior migratory routes. We examined this question by quantifying divergence in song, colour, and morphology between sister pairs of North American migratory birds. We predicted that apparent rates of phenotypic differentiation would differ between pairs that do and do not form migratory divides. Consistent with this prediction, results from mixed effects models and Ornstein–Uhlenbeck models of evolution showed different rates of divergence between these groups; surprisingly, differentiation was greater among non-divide pairs. We interpret this finding as a result of variable rates of population blending and fusion between partially diverged forms. Ancient pairs of populations that subsequently fused are now observed as a single form, whereas those that did not fuse are observable as pairs and included in our study. We propose that fusion of two populations is more likely to occur when they have similar migratory routes and little other phenotypic differentiation that would cause reproductive isolation. By contrast, pairs with migratory divides are more likely to remain reproductively isolated, even when differing little in other phenotypic traits. These findings suggest that migratory differences may be one among several isolating barriers that prevent divergent populations from fusing and thereby increase the likelihood that they will continue differentiating as distinct species.

Congrats to Dr. Delmore!


On July 21st, Kira Delmore expertly defended her Ph.D. dissertation, titled “Migratory Divides and the Genetic Basis of Reproductive Isolation.”

Dr. Delmore’s published dissertation chapters include the following:

Delmore, K.E., J.W. Fox, and D.E. Irwin. 2012. Dramatic intraspecific differences in migratory routes, stopover sites and wintering areas revealed using light-level geolocators. Proceedings of the Royal Society of London B 279: 4582-4589. Link;  PDF

Delmore, K.E., and D.E. Irwin. 2014. Hybrid songbirds employ intermediate routes in a migratory divide. Ecology Letters 17: 1211-1218. Link

Delmore, K.E., S. Hübner, N.C. Kane, R. Schuster, R.L. Andrew, F. Câmara, R. Guigo, and D.E. Irwin. 2015. Genomic analysis of a migratory divide reveals candidate genes for migration and implicates selective sweeps in generating islands of differentiation. Molecular Ecology 24: 1873-1888. Link

With more on the way!

Some coverage in the media:

Scientific American
Discover Magazine blog
Tech Times
UBC press release

Read more about Kira’s work (including lots of links to media coverage) here.

Congrats Dr. Delmore!!

Congrats to Alison Porter on her MSc defense!


Alison did an excellent job presenting and defending her MSc thesis, titled “An analysis of ecological traits as reproductive barriers between the MacGillivray’s (Geothlypis tolmiei) and Mourning (G. philadelphia) warblers.”

Congrats Alison!

Paper on niche similarity within long-toed salamanders published by Dr. Lee-Yaw


Congrats to Julie!

Lee-Yaw, J.A., and D.E. Irwin. 2015. The importance (or lack thereof) of niche divergence to the maintenance of a northern species complex: the case of the long-toed salamander (Ambystoma macrodactylum Baird). Journal of Evolutionary Biology 28: 917-930. Link

My favourite tweet about this paper:

:  alternative title… One niche to rule them all: the case of the long-toed salamander (Ambystoma macrodactylum)


Julie Lee-Yaw and Talia Sechley publish paper on salamander movement & landscape connectivity


Congrats to Julie and Talia!

Lee-Yaw, J.A.*, T. Sechley*, and D.E. Irwin. 2015. Conflicting effects of microhabitat on long-toed salamander Ambystoma macrodactylum) movement: implications for landscape connectivity. Canadian Journal of Zoology 93: 1-7. *These authors contributed equally to this work and should both be considered first authors.  Link

Welcome to Silu Wang, new Ph.D. student


Silu recently arrived from Molly Cummings’ lab at UT Austin, where she received an M.A. in Ecology, Evolution & Behavior for her thesis work on “Behavior, morphology and genetic signatures of sexual selection in poeciliid fish.”

Welcome Silu!!