Dr Kristal E Cain

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Senior Lecturer


I'm an integrative biologist working to understand why animals differ in thier expression of traits like ornaments, weapons and aggressive behaviours. In particular, I focus on how those traits are regulated, and how changes in ecology might favor animals to change.

  • B.S. Texas A&M University - Wildlife Ecology
  • Ph.D. Indiana University - Ecology, Evolution & Behavior
  • Postdoctoral Fellow at Australian National University - Ecology, Evolution & Genetics

Research | Current

The enigma of competitive traits

Bright colors, lethal weaponry, bizarre ornaments, complex songs, intense aggression. These sorts of traits are gaudy and costly, and seem to scream, “Here I am, come eat me”. Consequently, they have been a source of fascination for biologist for decades. But after decades of research, we have a  good understanding for why they exist.

But we don't see these traits just in males. There are many species with females that have weapons, fight, display bizarre ornaments, and sing complex songs. This is puzzling for biologists, females are supposed to be limited by egg production and offspring care, and ornaments and competitive behaviours traits take energy away from those things. So why are they so common?

There are multiple ways to tackle this problem. We can ask WHY females have these traits, and to answer that we’d need to look at whether these traits are helpful or costly, an if the answer is different in different contexts. We can also ask, HOW are females expressing these traits? In other words, what aspects of the female affects the traits, is it controlled by genetics? Is it affected by early life experiences? Can the female change the trait if she finds herself in a new situation?

My research program integrates these two perspectives in order to develop a better understanding of how and why females express competitive phenotypes.

Female Gouldian finchFemale fairy-wren


Teaching | Current

  • BIOSCI 206, Principles of Ecology
  • BIOSCI 207, Vertebrate Zoology
  • BIOSCI 337, Animal Behaviour
  • BIOSCI 338, Biology of Terrestrial Animals
  • BIOSCI 735, Advanced Behavioural Ecology

Postgraduate supervision

PhD student:  C Young (Australian National University). Mechanisms, function and the evolution of aggression in crimson finches

Areas of expertise

  • Behaviour
  • Evolution
  • Ecology
  • Sex differences
  • Hormones
    • Birds
    • Reptiles
    • Mammals

Selected publications and creative works (Research Outputs)

  • Cain, K. E., & Pryke, S. R. (2017). Testosterone production in response to exogenous gonadotropin releasing hormone (GnRH challenge) depends on social environment and color polymorphism. General and Comparative Endocrinology, 244, 77-85. 10.1016/j.ygcen.2015.12.029
    URL: http://hdl.handle.net/2292/33312
  • Cain, K. E., & Langmore, N. E. (2016). Female song and aggression show contrasting relationships to reproductive success when habitat quality differs. Behavioral Ecology and Sociobiology, 70 (11), 1867-1877. 10.1007/s00265-016-2192-1
    URL: http://hdl.handle.net/2292/33445
  • Cain, K. E., Jawor, J. M., & McGlothlin, J. W. (2016). Individual variation and selection on hormone-mediated phenotypes in male and female dark-eyed juncos. In E. D. Ketterson, J. W. Atwell (Eds.) Snowbird: Integrative Biology and Evolutionary Diversity in the Junco (pp. 120-147). Chicago: University of Chicago. 10.7208/chicago/9780226330808.003.0006
  • Cain, K. E., Cockburn, A., & Langmore, N. E. (2015). Female song rates in response to simulated intruder are positively related to reproductive success. Frontiers in Ecology and Evolution, 3.10.3389/fevo.2015.00119
    URL: http://hdl.handle.net/2292/30009
  • Cain, K. E., & Rosvall, K. A. (2014). Next steps for understanding the selective relevance of female-female competition. Frontiers in Ecology and Evolution, 2.10.3389/fevo.2014.00032
    URL: http://hdl.handle.net/2292/30049
  • Cain, K. E., & Ketterson, E. D. (2013). Individual variation in testosterone and parental care in a female songbird; The dark-eyed junco (Junco hyemalis). Hormones and Behavior, 64 (4), 685-692. 10.1016/j.yhbeh.2013.09.002
    URL: http://hdl.handle.net/2292/30046
  • Cain, K. E., & Ketterson, E. D. (2012). Competitive females are successful females; phenotype, mechanism and selection in a common songbird. Behavioral ecology and sociobiology, 66 (2), 241-252. 10.1007/s00265-011-1272-5


Contact details

Primary office location

COMMERCE A - Bldg 114
Level 1, Room 114
New Zealand

Web links