Research
Environmental influences on the evolution of ornamentation
Males of many species use sexual signals to attract and display to females. Variation in these traits can lead to differential reproductive success, sometimes resulting in only the most ornamented males siring offspring. However, in some species young males exhibit no ornamentation despite ornamentation conferring reproductive benefits. Male Red-backed Fairywrens can take up to three years to acquire the ornamented red and black plumage the species is known for. Starting in my PhD and now continuing with further projects, I have been studying how temperature, rainfall, and social environment influence when male Red-backed Fairywrens obtain the ornamented plumage, and the consequences associated with obtaining this plumage.
Findings:
Young male Red-backed Fairywrens obtain ornamented plumage when they pair with a female, but older males who are already paired obtain ornamented plumage when there’s enough rainfall. Paper.
Young male Red-backed Fairywrens that molt into ornamented plumage suffer increased social costs relative to young males that remain in brown, non-breeding plumage. In revision.
Timing of molt into ornamented plumage is associated with increased reproductive benefits in Red-backed Fairywrens. In prep.
Evolution of social behavior in relation to environmental variation
A species social structure plays an important role in determining its biology, but scientists are increasingly recognizing that social structure is shaped by environmental variation, even within species. Starting in my PhD and now continuing after, I have been studying how social structure varies across fairywren species and populations, especially how intraspecific responses to environmental variation are shaped by species’ evolutionary histories.
Findings:
Rainfall and photoperiod are associated with season transitions from non-breeding to breeding social structure in Red-backed Fairywrens. Paper.
Differences in the costs and benefits of sociality are associated with different intraspecific responses to environmental variation in Superb and Purple-backed Fairywrens. Paper.
Differences in social structure among White-winged Fairywren subspecies are associated with differences in androgen responses to courtship and aggression. Paper.
Natural and sexual selection for advanced spatial cognition
Finding food is necessary for survival. Mountain Chickadees are one of the few species that remain in the Sierra Nevada mountains year-round, including throughout the winter when insect prey is scarce. To survive through harsh, snowy winters, Mountain Chickadees cache pine seeds in tree bark and lichen during the fall, then rely on these caches throughout the winter in order to survive. Chickadees store a single seed per cache, meaning individual birds need to remember tens of thousands of locations. Working with Dr. Vladimir Pravosudov at the University of Nevada, Reno for my Postdoc, I have been investigating how natural and sexual selection has shaped the spatial cognitive abilities of Mountain Chickadees, allowing them to survive in harsh, snowy habitats where 17 feet of accumulated snow is possible each winter.
Findings:
Signal variation on a continental scale
Acquiring sexual signals often incurs costs that scale relative to the quality of the signal, meaning only the highest quality individuals can produce the highest quality signals. For example, females may prefer males with long tails, but long tails may be associated with increased predation risk and will require more resources and energy to produce, meaning only the highest-quality males will be able to acquire the resources needed to produce and maintain long tails. Decades of research has produced a wealth of examples of similar tradeoffs between natural and sexual selection, but most of these studies come from single populations. However, evolution works at the population level when populations evolve in response to local conditions. Through my citizen science project, my collaborators and I are investigating how these tradeoffs between natural and sexual selection vary across environments on a continental scale. Specifically, I’m investigating how male acquisition of ornamented plumage is affected by environmental variation and whether the relationships between environmental variation and signal acquisition are consistent across populations and species. Read more at www.fairywrenproject.org.
Working with citizen scientists to answer their research questions
Scientists spend their lives training to understand the natural world, but we cannot be everywhere at once. Further, making important discoveries does not always require having an advanced degree. Over the last few years I’ve been working with citizen scientists to answer their own questions about the Australian Fairywrens. One of our first articles has described three new observations of cross-species hybridization in the fairywrens, all documented by photographers and birders local to where the hybrids were found. Paper.
Drawing of a potential Red-backed x Superb Fairywren hybrid.