Research | College of Biological Sciences

Ecology and evolutionary biology of urban contaminants
As part of the MSP-LTER, we are studying how human pollutants such as salts, metals, and microplastics are moving through urban ecosystems and why species vary in their tolerance to such toxins. We strive to use data collected as part of this project to help in restoration of urban habitats, conservation of biodiversity, and improvements to human health and wellbeing in urban landscapes. Current projects under this umbrella are funded by the MN-Futures program, MN-ENRTF, and UMN's Institute on the Environment. We are working with several partners in the Twin Cities, including Urban Roots, Wakan Tipi, and Tamales y Bicicletas.

Roadsides as habitat for pollinators
As part of work funded by MnDoT and MN-ENRTF, we have been studying roadsides as habitat for pollinators (bees, butterflies). We have considered the risks of roadside salt and heavy metal pollution (much of this work is summarized here) and the efficacy of seeding roadsides with native plants (report here). Representative publications address attraction of ovipositing butterflies to sodium, movement of salt and metals into roadside plants, and toxicity of such metals and salts to larval butterflies (and bees). In future work, we are interested in microplastics as road pollutants, and road-crossing behavior.

Costs and constraints in the evolution of plasticity
Why are some species flexible in their behavior and development, while others are more fixed or specialized (e.g., this review)? What does this mean for survival in novel environments (e.g., this review)? We use butterflies (and sometimes other systems) to test hypotheses about variation in costs of plasticity, and variation in selection on plasticity. For instance, forms of plasticity like learning may be more likely to tradeoff with reproduction (e.g., this study in cabbage whites) than switch-like forms of plasticity, that are limited by the efficacy of selection (e.g., this study in horned beetles). For forms of plasticity that are costly, availability of resources may set limits on allocation to both plasticity (e.g., brain size) and reproduction.

Sexual selection in anthropogenic environments
Humans are drastically altering the nutritional and sensory environments that affect the development of sexual traits. How does this alter sexual selection dynamics and what are the implications for population divergence and eventually speciation? We have considered how sexual signals may shift in agricultural environments where nutrient availability has increased and once-honest signals may become dishonest (see here). More recently, we are studying how male signals, female sensory systems, and mate choice shift in cabbage whites growing in shadier conditions (e.g., in open forests where garlic mustard grows, see left).