Multivariate models of animal sex: breaking binaries leads to a better understanding of ecology and evolution.


'Sex' is often used to describe a suite of phenotypic and genotypic traits of an organism related to reproduction. However, these traits - gamete type, chromosomal inheritance, physiology, morphology, behavior, etc. - are not necessarily coupled, and the rhetorical collapse of variation into a single term elides much of the complexity inherent in sexual phenotypes. We argue that consideration of 'sex' as a constructed category operating at multiple biological levels opens up new avenues for inquiry in our study of biological variation. We apply this framework to three case studies that illustrate the diversity of sex variation, from decoupling sexual phenotypes to the evolutionary and ecological consequences of intrasexual polymorphisms. We argue that instead of assuming binary sex in these systems, some may be better categorized as multivariate and nonbinary. Finally, we conduct a meta-analysis of terms used to describe diversity in sexual phenotypes in the scientific literature to highlight how a multivariate model of sex can clarify, rather than cloud, studies of sexual diversity within and across species. We argue that such an expanded framework of 'sex' better equips us to understand evolutionary processes, and that as biologists it is incumbent upon us to push back against misunderstandings of the biology of sexual phenotypes that enact harm on marginalized communities.





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Publication Info

McLaughlin, JF, Kinsey M Brock, Isabella Gates, Anisha Pethkar, Marcus Piattoni, Alexis Rossi and Sara E Lipshutz (2023). Multivariate models of animal sex: breaking binaries leads to a better understanding of ecology and evolution. Integrative and comparative biology. p. icad027. 10.1093/icb/icad027 Retrieved from

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Sara E Lipshutz

Assistant Professor of Biology

Our research focuses on the evolution of behavior across weird and wonderfully diverse species of birds. This work bridges “muddy boots” experimental fieldwork with a variety of molecular and computational approaches in genetics, genomics, neuroscience, and endocrinology. We have several research foci:  


1. Female perspectives in biology. Cultural biases shape our predictions for how and why animals behave the way they do, and female animals have historically been neglected in biological research. We study the evolution of female competition across diverse avian species, ranging from social polyandry to monogamy in shorebirds and songbirds. Critically, hypotheses derived from studying males (i.e. testosterone focus) do not explain interspecific variation in female aggression. We use population genomic and transcriptomic data to evaluate the proximate causes and ultimate consequences of female competition.  


2. Global change biology. In the age of the Anthropocene, animals are facing evolutionary unprecedented environmental changes. Sensory pollutants like anthropogenic noise and artificial light at night can alter animal physiology, behavior, and ecology on a rapid timescale. Behavior flexibility and adaptation may lead the way in helping animals respond to novel challenges. We investigate why some individuals and species may be better prepared to face global change.  

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