Research
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Phenotypic plasticity and the biogeography of complex communication:
When animals combine multiple signals during communication, differences in the degree of plasticity among those signals could affect their coordinated functions in novel environments. This plasticity should (i) determine whether selection can act on complex, coordinated displays and (ii) also limit where species with complex displays can effectively communicate and persist. I explore these ideas using Schizocosa wolf spiders and Habronattus jumping spiders, which coordinate complex combinations of vibrational courtship, dynamic gestures, and ornate coloration to attract and compete for mates. This work combines experiments in the lab, phylogenetic methods, geospatial analyses, and data from global biodiversity facilities. Overall, this ongoing project is uncovering a key missing link in the origins of complex animal communication. It also empirically demonstrates how communication systems adapt and mediate species persistence during community assembly. Collaborators: Elias Lab (UC Berkeley); Fowler-Finn Lab (Saint Louis U.) Funded by NSF Postdoctoral Research Fellowship in Biology |
Schizocosa wolf spiders evolve more complex mating displays in climates that promote signal co-expression
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The role of communication in epidemic dynamics:
Heatwaves and other key axes of anthropogenic change are increasing the risk of disease outbreaks in human and wildlife populations. A major challenge in predicting epidemic dynamics in altered environments is understanding how plasticity in host behavioral resilience impacts transmission. I am testing how differences in social communication during heatwaves shape the transmission of Gyrodactylus ectoparasites in experimental populations of Trinidadian guppies. I have found that heatwaves that occur early on in an epidemic destabilize patterns of Gyrodactylus transmission, ranging from rapid infection of all guppy hosts to almost complete infection fade-out. We are currently analyzing daily epidemic videos with AI-driven individual tracking software to test if transmission correlates with heatwave-induced changes in infection indicating color signals and social behavior networks. Collaborators: Stephenson Lab (U Stockholm); Kohl Lab (U Pittsburgh) Funded by University of Pittsburgh Ecology & Evolution Postdoctoral Fellowship |
Poecilia reticulata guppies infected with Gyrodactylus worms. Photo by Faith Rovenolt
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Co-adaptation of sexual signals and eco-physiology:
Adaptation to different climates and adaptations in sexual communication have long been considered major drivers of biodiversity. However, we are only now appreciating the close links between these two immense but historically disparate research areas. My work shows that temperature pervasively affects the expression and evolution of sexual signals. At the same time, dark sexual coloration also absorbs more heat from the sun, vigorous courtship and combat generates metabolic heat, and animals often produce displays in exposed habitats with extreme microclimates. The evolution of physiological traits like heat tolerance and metabolic reaction norms should therefore co-adapt with sexual signals to enhance reproductive performance. In fact, I found that dragonfly species compensate for their dark, heat-absorbing sexual coloration by evolving to physiologically tolerate extra heating. My ongoing work in Habronattus jumping spiders is also testing if selection favoring complex sexual signals indirectly facilitates local adaptation in metabolic performance across elevational and latitudinal gradients. Overall, this work suggests that widespread evolutionary feedback between thermal physiology and sexual selection is an important driver of ecological divergence and Earth’s captivating diversity of sexual signals. Publications: Leith et al. 2022 Eco Letts; Leith et al. 2024 Front Ethol; Somjee et al. 2025 ICB Collaborators: Moore Lab (CU Denver); Elias Lab (UC Berkeley) |
Dragonfly species with heat-absorbing sexual coloration also evolve to physiologically tolerate hotter body temperatures
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Impacts of sexual selection on extinction and persistence in the wild:
The signals that animals use to attract and compete for mates can also confer unique costs and benefits in the face of anthropogenic threats. On one hand, exaggerated sexual signals can be especially costly to produce and may further threaten persistence in altered environments. Conversely, effective sexual communication can facilitate resilience by helping animals locate their mates, identify the correct species to mate with, and avoid injurious mating contests. My collaborators and I tested if the evolution of sexual coloration in dragonflies predicts vulnerability to global change at population, regional, and continental scales. We found that dragonfly species with sexual coloration on their wings have lower extinction risk in regions where habitats have been lost to urbanization and agricultural land use. Similarly, my work on wolf spiders found that species that have evolved complex courtship displays and exaggerated sexual ornaments are less likely to go extinct in regions that have become hotter and wetter in the last 50 years. Sexual signal evolution is thus an important but currently understudied feature of adaptation that can predict extinction in response to global change. Publications: Moore & Leith et al. 2024 Eco Letts Collaborators: Moore Lab (CU Denver); Fowler-Finn Lab (Saint Louis U) |
Dragonflies that evolve sexual coloration on their wings are less vulnerable to extinction in degraded habitats
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Behavior and development shape population dynamics at microclimate scales:
Increasingly extreme and unpredictable temperatures are leading threats to biodiversity. Understanding the processes that promote or forestall extinction in the wake of global warming is therefore paramount to limiting biodiversity loss. Breakdowns in reproduction could disproportionally influence species’ vulnerability to climate change compared to reduced survival, as mating success is often limited to a narrow window of temperatures. My combination of thermal imaging techniques, acoustic playbacks experiments, and mesocosm studies revealed that many small insects likely cannot thermoregulate to enhance sexual communication and mating success. Recently, my collaborators and I synthesized years of experiments with simulation-based population dynamic models showing that developmental plasticity in warming climates could buffer insects against mortality-driven extinction by enhancing fertility and fecundity. Collectively, we clearly demonstrate that overlooking the thermal sensitivity of reproduction leads us to inaccurately predict extinction risk in rapidly changing climates. Publications: Leith et al. 2025 Eco Letts; Leith et el. 2024 Func Ecol; Leith et el. 2021 COIS; Leith et el. 2020 Ethol Collaborators: Fowler-Finn Lab (Saint Louis U); Tenhumberg Lab (UN Lincoln) |
A group of Enchenopa binotata treehoppers
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Banner photo of male Habronattus americanus provided by Lin Yan