Uncovering evolutionary history
to predict and protect the future

The overarching goal of my research is to reveal molecular adaptations and phylogenetic/population genetic history to address how species might react to changing natural and agricultural landscapes. I also collaborate with diverse stakeholders to use this knowledge in developing optimized strategies for conserving species.

Current Projects

Sierra Nevada Bumble Bee Health Project: Understanding and mitigating the effects of agricultural intensification on our most economically important native pollinator

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Poor nutrition due to a lack of floral resources, pesticide exposure, and climate change are all components of agricultural intensification that have direct affects on the health, stability, and fitness of pollinators. When acting together they undoubtedly also have synergistic effects. My USDA NIFA ELI Postdoctoral Fellowship projects aims to address how these factors work individually and synergistically to affect bumble bee health at the individual level via laboratory manipulations and at the population level through wild bumble bees in the Sierra Nevada.

The results of this project will be used to help develop environmentally-sustainable and conservation-conscious commercial bumble bee rearing practices, as well as evidence-based conservation strategies for restoring bumble bee habitat.

Carolyn Wilke and Randall Benton from The Sacramento Bee joined me in the field one day this summer and wrote this article about my research in the Sierras!

Assessing conservation threats to Arctic bumble bees by surveying parasite prevalence across species and regions


Funded in part by the Arctic Institute of North America, I have begun an in-depth survey of the parasites and pathogens that affect bumble bees in the delicate, fast-changing ecoregions of Alaska. The main goal of this project is to gain a broad, comprehensive understanding of parasite prevalence and abundance. I will also be comparing infection patterns between populations of species that inhabit both Alaska and California to understand how commonly known pathogen threats in mainland US might have differential affects in far North Alaska, where there are no honey bees and no commercial bumble bee industry.

Jim Gorman and Katie Orlinsky of the New York Times travelled with our expedition team to Alaska last summer and created this great interactive feature and article about our research and the trip!

Past Projects

Phylogeography and population genetics of the Bombus ephippiatus species complex


For part of my dissertation research, I explored how the mountain ranges of Mesoamerica shaped genetic and morphological diversity in the bumble bee Bombus ephippiatus. This beautiful montane bee exhibits a high amount of color polymorphism across its widespread range. It is unique among bumble bees because in many parts of its range it exhibits queen/worker-male dimorphism in color pattern. It also lives in a diversity of habitats across its range, and I have found that there is extensive genetic diversity in this lineage (Duennes et al. 2012; Duennes et al. 2016). This genetic diversity in part correlates well with color pattern diversity, and seems to be structured by three important geographic barriers: the Isthmus of Tehuantepec, the Central Depression, and the Nicaraguan Depression.

This project was an integral part of a large effort to examine the conservation status of all bumble bees worldwide by the Bumble Bee Specialist Group for the International Union for the Conservation of Nature (IUCN).

Evolutionary development of color pattern in bumble bees

Rapti et al. 2014

Across their worldwide distribution, bumble bees exhibit a variety of aposematic, warning color patterns to predators, but how these diverse patterns are developmentally controlled and modified is unknown. Another project I worked on for my dissertation aimed to identify the main “elements” that make up the diverse array color patterns that exist in all bumble bees using a highly detailed quantitative matrix method (that involved drawing by hand over 300 bumble bees!). Across all bumble bees we found 12 conserved primary “ground plan” elements that correlate strongly with segmentation patterns, suggesting that color pattern in bumble bees might be controlled by early developmental controls like Hox genes. You can read all about our matrix method and results in the Biological Journal of the Linnean Society.