How does the social environment shape the evolution of traits?

I combine field-based empirical methods with mathematical modeling to understand how the ecology of social environments influences trait evolution. I typically focus on reproductive traits, often behavioral ones. As a model for understanding processes involved in social evolution and the patterns of biodiversity that they produce, I currently investigate the evolution of ornaments and sexual signals in female animals living in polygynous mating systems.

The ecology and evolution of a sexual signal (and other costly strategies) in female primates.

One of the main questions that has driven my past and current research is, why do females of some species display sexual signals even in polygynous species? In this type of mating system (where females are not mate-limited but males are), female traits should not be subject to selection that arises from competition for fertilizations (classic sexual selection.) Nonetheless, these kinds of traits are found among females across taxa (e.g. primates, fishes, lizards, crustaceans). One of the most commonly cited examples is found in Old World primates and has been the subject of my field-based empirical research to date. In collaboration with the Amboseli Baboon Research Project, I investigated the ecology and evolution of exaggerated estrous swellings in female baboons. This collaboration is ongoing and I am currently investigating the relationship between the social environment and variation in female fertility among the Amboseli baboons.

Using mathematical models to investigate the evolution of male mate choice and female ornamentation.

Mathematical modeling is a powerful tool for understanding biological processes when common logic is not up to the task of disentangling complex interactions and dynamics. I develop models, using primarily population genetic techniques, to examine fundamental principles underlying behavioral evolution and the evolution of reproductive strategies. I typically develop ‘proof-of-concept’ models, which investigate the logical relationships between hypotheses and predictions in order to clarify and formalize the conceptual frameworks that propel empirical research. In particular, I have focused on understanding the potential (or lack thereof) for male mate choice to result in evolution of female ornaments and some related questions about the evolution of male mate choice itself. I am currently investigating the relative contributions of direct and indirect genetic effects on the evolution of female reproductive traits in polygynous mating systems.

1. Watts, JC, Fitzpatrick, CL. The effects of intersexual interactions on survival can drive the evolution of female ornaments in the absence of mate limitation. J Evol Biol. 2024;37 (11):1356-1367. doi: 10.1093/jeb/voae121. PubMed PMID:39302174 .
2. Ehrie, AJ, Iruri-Tucker, AA, Lord, YB, Williamson, HG, Hunt, KD, Polly, PD et al.. Measuring mantled howler monkey (Alouatta palliata) testes via parallel laser photogrammetry: Expanding the use of noninvasive methods. Am J Primatol. 2024;86 (6):e23616. doi: 10.1002/ajp.23616. PubMed PMID:38462743 .
3. DuVal, EH, Fitzpatrick, CL, Hobson, EA, Servedio, MR. Inferred Attractiveness: A generalized mechanism for sexual selection that can maintain variation in traits and preferences over time. PLoS Biol. 2023;21 (10):e3002269. doi: 10.1371/journal.pbio.3002269. PubMed PMID:37788233 PubMed Central PMC10547189.
4. Fitzpatrick, CL, Wade, MJ. When is Offspring Viability Fitness a Measure of Paternal Fitness and When is it not?. J Hered. 2022;113 (1):48-53. doi: 10.1093/jhered/esab055. PubMed PMID:34850026 PubMed Central PMC8851674.
5. Fitzpatrick, CL, Alter, SE, Boughman, JW, Débarre, F, Edmands, S, Moehring, A et al.. The virus evolves: four public health priorities for reducing the evolutionary potential of SARS-CoV-2. Bioscience. 2021;71 (4):319. doi: 10.1093/biosci/biab037. PubMed PMID:34191918 PubMed Central PMC8083273.
6. Fitzpatrick, C, Ciresi, CM, Wade, MJ. The evolutionary genetics of paternal care: How good genes and extrapair copulation affect the trade-off between paternal care and mating success. Ecol Evol. 2021;11 (3):1165-1174. doi: 10.1002/ece3.7058. PubMed PMID:33598121 PubMed Central PMC7863384.
7. Grebe, NM, Fitzpatrick, C, Sharrock, K, Starling, A, Drea, CM. Organizational and activational androgens, lemur social play, and the ontogeny of female dominance. Horm Behav. 2019;115 :104554. doi: 10.1016/j.yhbeh.2019.07.002. PubMed PMID:31276664 .
8. Fitzpatrick, CL, Servedio, MR, Handling editor: Ingo Schlupp. The evolution of male mate choice and female ornamentation: a review of mathematical models. Curr Zool. 2018;64 (3):323-333. doi: 10.1093/cz/zoy029. PubMed PMID:30402075 PubMed Central PMC6007321.
9. Fitzpatrick, CL, Hobson, EA, Mendelson, TC, Rodríguez, RL, Safran, RJ, Scordato, ESC et al.. Theory Meets Empiry: A Citation Network Analysis. Bioscience. 2018;68 (10):805-812. doi: 10.1093/biosci/biy083. PubMed PMID:30364335 PubMed Central PMC6195343.
10. Wade, MJ, Fitzpatrick, CL, Lively, CM. 50-year anniversary of Lloyd's "mean crowding": Ideas on patchy distributions. J Anim Ecol. 2018;87 (5):1221-1226. doi: 10.1111/1365-2656.12854. PubMed PMID:29802804 PubMed Central PMC6611668.