An animal’s movement through its environment determines how easily and how often it encounters other individuals or particular habitats, and thus dictates the selective pressures it faces. I study how animals use and move through the space they occupy, because I believe this framing offers a unique perspective on myriad aspects of animals’ behavioral ecology.
[Links to publications arising from this work can be found on the CV page. Links below are to blog posts discussing the research mentioned.]
Social Spider Web Architecture
My postdoctoral research in the Pruitt Lab explores questions of coevolution between animal architecture and collective behaviors in Stegodyphus spiders, to understand if the spatial environments these animals build for themselves facilitate the adaptive social interactions that help their colonies succeed.
Anolis lizard mating systems
Decades of behavioral research on Anolis lizards’ social organization and mating systems resulted in near-unanimous support for the hypothesis that these lizards are territorial and polygynous. Under this hypothesis, males defend territories to maintain exclusive mating access to females; each female therefore mates with only one male. However, this behavioral description is inconsistent with genetic data that repeatedly show that female Anolis mate with multiple males.
I approached this mismatch by re-evaluating Anolis territoriality in two ways. First, I reviewed the historical progression of scientific evidence for territoriality and polygyny in a century of research on Anolis lizards. I found that early studies based their conclusion that anoles are territorial on flimsy evidence. Later studies, taking prior conclusions at face value, ended up being designed such that they were unlikely to detect, or even consider important, variation in movement behavior and social interactions that was inconsistent with territoriality. Thus, Anolis territoriality became something of a self-fulfilling prophecy, and we know less about Anolis mating systems than we think we do (see here and here for further details and discussion).
Second, I quantified the movement patterns of a population of Anolis sagrei and estimated the co-occurrences of males and females in space and time, instead of mapping territory overlap, to describe encounters between potential mates. My research revealed that these lizards’ movement behavior is almost never consistent with territoriality, and is far more dynamic than previously thought, leading females to frequently encounter multiple males. Thus, their movement patterns bring about polygynandrous reproductive dynamics, revealing the possibility for female mate choice to be an important selective force in Anolis lizards.
Further, I estimated sexual selection on male A. sagrei, integrating movement patterns with genetic estimates of male reproductive success to first focus on the males encountered by females and then on the subset of these males that sired females’ offspring. This approach showed that larger body size is consistently favored in males, but also revealed the potential for sexual selection on male movement behavior and on the temporal dynamics of male-female encounters.
Individual variation in Anolis sagrei habitat use
Anolis lizards are a textbook example of convergent evolution. Species of anoles have independently converged in a suite of behavioral, ecological, and morphological traits, repeatedly evolving a community of habitat-use specialists whose morphologies are adapted to the particular habitat they occupy, but we do not know if these patterns of macroevolution in Anolis are simply patterns of microevolution “writ large.”
I found that individuals within a population of A. sagrei are specialized in their habitat use, to a degree comparable to the specialization seen across species in a community of Anolis. However, this specialization is not associated with morphological traits in the same way that it is across species—rather than an individual’s habitat use being associated with traits involved in performance, it is associated with body size in males but not females. Because body size in Anolis is crucial for determining male reproductive success, these results suggest that instead of choosing to live in the habitats for which they are best-adapted for avoiding predators or hunting for food, individuals’ habitat use may be shaped by their social interactions and sexual selection.
- An across-population study of variation in morphology and display behavior in the fan-throated lizard (Sitana and Sarada; Agamidae) species complex. Here is a summary of my findings midway through the project.
- Variation in dorsal patterning, habitat use, and escape behavior in female Anolis sagrei (with Rachel Moon).
- Ecomorphology of the Anolis lizards of La Selva (with Christian Perez).
- Convergent evolution of head shape in vine snakes (with Christian Perez).
- Individual variation in the display behavior of male Anolis sagrei lizards (with Jonathan Suh).
- Relationships between microhabitat, colour, and calling rates in two spatially distinct breeding populations of the Western Ghats golden frog, a common but poorly studied species (with Sreekar Rachakonda)
- Movement rates and microhabitat locations for feeding and displaying in green anoles (Anolis carolinensis) in the presence and absence of a congeneric competitor, Anolis sagrei (with Yoel Stuart; summarized here, here and here).
- The evolution of sexual dimorphism in the floral biology of Lycium californicum (with Jill Miller and Rachel Levin).
- Determining the direction of dispersal of Lycium between Africa and east Asia, using the remarkable S-RNase mating system locus to infer population history (with Jill Miller, Rachel Levin, and Julian Damashek).
- Reductionism, nonlinearity, and a gene’s eye view of natural selection (advised by Suhel Quader).