Research
Photo: Measuring aerosol formation above transgenic tobacco plants in Mainz (DE)
I am insect parasite ecologist whose research addresses how floral chemistry, temperature, and non-pathogenic microbiota affect the parasites and pathogens of honey and bumble bees, to better understand the ecology and evolution of infection in insects that are critical for wild and crop plant pollination. Understanding how ecological factors—including floral chemistry, temperature, and gut microbiota—shape infectious diseases in pollinators has fundamental value for knowledge of host-parasite interactions, and applied potential for predicting and reducing risks of infection in managed and wild bees.
How do temperature and gut microbiota affect bee parasites?
Many animals elevate their body temperatures when infected with parasites and pathogens. These elevations in body temperature ('fever')-- whether achieved by metabolic heat production or behavioral changes-- can improve resistance and tolerance to infection in mammals, insects, and reptiles. In addition to temperature, recent research has documented the importance of non-pathogenic gut bacteria in defense against infection. However, few studies have considered the relative effects of elevated temperatures on pathogenic and non-pathogenic microbes. Do elevated temperatures cause collateral damage to beneficial bacteria? Or does fever selectively favor beneficial microbes at the expense of pathogens? My postdoctoral studies at UC Riverside investigated these questions in the bumble bee/Crithidia bombi host-parasite system. I am continuing this research using related trypanosomatids from honey bees (Crithidia mellificae and Lotmaria passim).
Articles:
Hot and sour: parasite adaptations to honey bee body temperature and pH https://t.co/AXi7qc990G (Preprint)
Heat and acid in honey bee hosts
Mimic mammals' Leishmania moats
Low-pH gut ferment
Structures flagellates' ascent
Heat from honey makes parasites toast
High body temperature and acidic gut pH are two factors that inhibit parasitic infection. The high colony temperatures and acidic guts of social bees relative to other insects provide unique opportunities to test how temperature and acidity shape insect-parasite associations and potential for spillover into warm-blooded mammals. We show that parasites of honey bees have greater tolerance of heat and acidity than do related parasites of mosquitoes, which lack both temperature regulation and gut acidity. This suggests that honey bees’ colony-enabled temperature regulation and gut chemistry provide resistance to non-specialist parasites, favoring the same parasite traits needed for mammalian infection.
pH-mediated inhibition of a bumble bee parasite by an intestinal symbiont
Temperature-mediated inhibition of a bumblebee parasite by an intestinal symbiont
Temperature dependence of parasitic infection and gut bacterial communities in bumble bees
Cross infection of honey and bumble bee parasites in bees of three families
How do nectar and pollen secondary metabolites affect bee parasites?
Nectar and pollen contain antimicrobial phytochemicals, some of which can reduce disease in animals. Floral phytochemicals could therefore influence the ecological and evolutionary relationships between plants, their pollinators, and parasites that cause pollinator disease. Antiparasitic effects of phytochemicals could be exploited to ameliorate pollinator disease and decline, and thereby sustain pollinator-dependent agricultural production. I tested effects of phytochemicals on a trypanosomatid parasite of bumble bees (Crithidia bombi) to identify phytochemicals that inhibited growth, and tested for evolution of resistance to phytochemicals in parasites grown under high-phytochemical conditions.This research showed the potential of phytochemical-rich flowers to ameliorate pollinator infection—a recognized contributor to bee decline—but caution that chronic phytochemical exposure could diminish effects of phytochemicals on parasites. Planting of high-phytochemical crops and hedgerow species could reduce effects of disease on bee populations, thereby benefitting agricultural production. I am currently evaluating the effects of phytochemicals on virus infection in honey bees.
Articles: Host ecology-associated differences in phytochemical tolerance between bee and mosquito parasites Video: Punch in the gut
Potential for floral nectars to combat transmission of neglected tropical disease-causing Leishmania Video: Unleish the flies
Sunflower cropland and pollen for honey bee resistance to Varroa mites Video: Mites alight Blog post with Humberto Boncristiani on insidethehive.tv
Big survey of nectar and pollen secondary chemistry (Ecol. Monographs)
A guide to the dataset (Ecology)
Secondary chemistry of blueberry nectar and pollen (Frontiers Plant Sci)
Effects of short-term exposure to naturally occurring thymol concentrations on transmission of bee parasite (J. Ecological Ent.)
Effects of the floral phytochemical eugenol on parasite evolution and bumble bee infection and preference (Scientific Reports)
Phytochemicals boost honey bee immunity to Deformed wing virus (J. Economic Ent.)
Pollen extracts increase growth of Crithidia bombi (PeerJ)
Bumble bee parasite evolves resistance to inhibitory phytochemicals (J. Evolutionary Biology)
Video: Pathogen of most resistance
This article was recommended by Alison Duncan and Sara Magalhaes at the brand-new Peer Community in Evolutionary Bio.
Synergistic effects of eugenol and thymol against bee parasite Crithidia bombi
Resistance to phytochemicals across 4 strains of bee parasite Crithidia bombi (Scientific Reports)
Dose-dependent effects of anabasine on bumble bees (PLOS ONE)
Nicotine, thymol, and a bumble bee parasite (PLOS ONE)
Variable effects of nicotine and anabasine on bumble bees (F1000 Research)
Post-baccalaureate project on functions of plant volatiles
I spent 2009-2011 at the Max Planck Institute for Chemical Ecology (http://ice.mpg.de) in Jena, Germany. Working with Meredith Schuman, Jonathan Gershenzon, and Ian Baldwin, I tested the role of sesquiterpenes in plant resistance to oxidative stresses. I also explored the contribution of plant volatiles to local formation of aerosols. Our transgenic lines suffered a lot, but we have improved the fitness of their novel genotype by immortalizing them in two peer-reviewed publications.
Articles
Ectopic Terpene Synthase Expression Enhances Sesquiterpene Emission in Nicotiana attenuata without Altering Defense or Development of Transgenic Plants
I graduated from Cornell University in 2009 in Biology with a Neurobiology and Behavior concentration. I conducted an independent study project with Paul Sherman on the antimicrobial properties of the fermented milk kefir. In 2009 I had a National Science Foundation Research Experience for Undergraduates (NSF REU) at the Institute of Ecosystem Studies (IES, Millbrook, NY, www.ies.org) studying nitrate reduction in sediments of Onondaga Lake (Syracuse, NY).
For a complete summary, see my CV and Google Scholar page.