Biography
I grew up in Montana (USA) and earned a B.A. from Wesleyan University in Middletown, CT in 1998 and a Ph.D. in Organismal Biology and Ecology from the University of Montana in 2007. I work on the evolution of morphology and behavior, particularly in the field of sexual selection. While based at the University of Florida (2007-2024) , I received numerous grants and awards including a $1.2M award (2022-2026) from the National Science Foundation (NSF) and the NSF CAREER Award (2016-2022). I care deeply about mentorship and teaching and was presented the USDA National Excellence in College and University Teaching Award (2017) and the University of Florida College of Agriculture and Life Sciences Undergraduate Teacher of the Year Award (2018). I moved here in 2024 to accept a position as a Professor of Biotic Interactions.
Research
Picture the fearsome tusks of prehistoric elephants and the incredible claws of fiddler crabs. These are sexually selected weapons, and they are used to gain matings with the opposite sex by getting members of the same sex out of the way. The sizes and shapes of such weapons are stunningly diverse across taxa as well as within closely related groups. For example, the African antelope have many kinds of horns: some species have tiny spikes while others have large twisting and curving horns that may be pointing up, down, outwards, or inwards. Understanding why weapons are so diverse requires considering their function. Sexually selected weapons have evolved, at least in part, to function in physical combat.
We use experimentation to understand the evolution of weapon size, shape, and function within species, and we use phylogenetic comparative analyses to understand cumulative changes in weapons across species. Ultimately, our interest is on the evolutionary interplay of morphology and behaviour, and weapons and physical combat provide an outstanding opportunity to understand this interaction.
We test our hypotheses using a superfamily of insects called the leaf-footed bugs. This group includes ~3,300 species in five extant families, and it is one of only a few animal groups that produce weapons on the hind legs. In some of these species the hind legs exhibit extreme modifications including robust spines, club-like expansions, flags, and serrations. The diversity of their hind leg shapes, their ecology, and their behaviours provide outstanding opportunities for our work.
Right now, we are thinking a lot about how seasonally changing plant environments influence male-male competition, weapon evolution, and the evolution of sexual dimorphism. With grant funding from the National Science Foundation, our team is examining how changes in host plants affect the growth and development of animal weapons and fighting behaviours. In the process of this work, we discovered that seasonal changes in host plants affect the ability of the insect body to hold up to battle. We are now diving deep to understand how nutrition influences the growth and development of the insect exoskeleton more broadly. After all, a large weapon means very little if it is easily punctured or crushed during competition.
In addition to our work on male-male competition, weapons, and the insect exoskeleton, we have investigated trade-offs between the growth of weapons and testes and studied the plasticity and evolution in insect mouthparts. We are still working actively in these areas as well.
Publications
Miller CW, Kimball RT & Forthman M (2024). The evolution of multi-component weapons in the superfamily of leaf-footed bugs. Evolution 78: 635–651.
Greenway EV, Angelis E & Miller CW (2023). How does the timing of weapon loss influence reproductive traits and trade-offs in the insect Narnia femorata? Evolution 77. 1422-1429.
Greenway EV, Hamel JA & Miller CW (2022). A tangled web: Comparing inter- and intraspecific mating dynamics in Anasa squash bugs. Journal of Evolutionary Biology 35: 91-99.
Woodman TE, Chen S, Emberts Z, Wilner D, Federle W & Miller CW. Developmental nutrition affects the structural integrity of a sexually selected weapon. Integrative and Comparative Biology 61: 723-735.
Allen PE, Cui Q & Miller CW (2021). Evidence of a rapid and adaptive response of hemipteran mouthparts to a physical barrier. Journal of Evolutionary Biology 34: 653-66.
Miller CW, Joseph PN & Emberts Z (2021). Trade-offs between weapons and testes do not manifest at high social densities. Journal of Evolutionary Biology. 34: 726-735.
Cavender K, Ricker T, Lyon M, Shelby E, Miller CW & Moore PJ (2021) The trade-off between investment in weapons and fertility is mediated through spermatogenesis in the leaf-footed cactus bug Narnia femorata. Ecology & Evolution. DOI: 10.1002/ece3.7686.
Greenway EV, Hamel J & Miller CW (2021). Exploring the effects of extreme polyandry on estimates of sexual selection and reproductive success. Behavioral Ecology. 32: 1055-1063.
Greenway EG, Cirino LA, Wilner D, Somjee U, Anagnostou ME, Hepple RT & Miller CW (2020). Extreme variation in testes size in an insect is linked to recent mating activity. Journal of Evolutionary Biology. 33: 142-150.
Miller CW, Joseph PN, Kilner RM, Emberts Z (2019). A weapons–testes trade-off in males is amplified in female traits. Proceedings of the Royal Society of London (B). 286: 20190906
Somjee U, Woods HA, Duell M, & Miller CW (2018). The hidden cost of sexually selected traits: the metabolic expense of maintaining a sexually selected weapon. Proceedings of the Royal Society of London (B). DOI: 10.1098/rspb.2018.1685.
Joseph PN, Emberts Z, Sasson DA, & Miller CW (2018). Males that drop a sexually-selected weapon grow larger testes. Evolution. 72: 113–122. DOI: 10.1111/evo.13387.
Somjee U, Miller CW, Tatarnic NJ, & Simmons LW (2018). Experimental manipulation reveals a trade-off between weapons and testes. Journal of Evolutionary Biology. 31: 57–65. DOI: 10.1111/jeb.13193.
Allen PE & Miller CW (2017). Novel host plant leads to the loss of sexual dimorphism in a sexually selected male weapon. Proceedings of the Royal Society of London (B). 284: 20171269.
Miller CW, McDonald G, & Moore AJ (2016). Seasonal changes in nutrition affect weapon size and sexual dimorphism, but not contemporary evolution. Journal of Evolutionary Biology. 29: 2266-2275. DOI: 10.1111/jeb.12954.
McCullough E, Miller CW, and Emlen DE (2016). Why sexually-selected weapons are not ornaments. Trends in Ecology and Evolution. 31: 742-751. DOI: 10.1016/j.tree.2016.07.004.
Gillespie SR, Tudor MS, Moore AJ, & Miller CW (2014). Sexual selection is influenced by both developmental and adult environments. Evolution 68: 3421-3432.
Miller CW & Svensson E (2014). Sexual selection in complex environments. Annual Review of Entomology 59: 427-445.
Miller CW (2013). Sexual selection: Male-male competition. In: J. Losos, Editor. The Princeton Guide to Evolution. Princeton University Press.
Procter DS, Moore AJ & Miller CW (2012). The form of sexual selection arising from male-male competition depends on the presence of females in the social environment. Journal of Evolutionary Biology 25: 803-812.
Miller CW (2008). Seasonal effects on offspring reproductive traits through maternal oviposition behavior. Behavioral ecology 19(6): 1297-1304.
Miller CW & Moore AJ (2007). A potential resolution to the lek paradox through indirect genetic effects. Proceedings of the Royal Society of London (B) 274:1279-1286.
