The lab is pursuing a diversity of research projects spanning bee evolutionary genetics, bee social evolution, bee epidemiology and conservation, and parasitic wasp evolution:
Evolution and genetics of mimetic coloration in bumble bees
The ~250 species of the cold-adapted bumble bees are exceptionally color diverse, comprising >400 different patterns in their setal pile coloration across their body segments. One of the main factors driving such variation is localized selection through Müllerian mimicry – taxonomically diverse species in the same geographic region have convergently evolved a similar color pattern because selection favors shared advertisement of their toxicity (their sting) to predators. Bumble bee color diversity thus provides extensive replicates for understanding how traits evolve rapidly and repeatedly at the genetic level and to understand how ecological factors influence the formation of mimicry complexes over time. Furthermore the segmental nature of their color change makes this a great system to understand the role of segmentation genes in phenotypic variation.
Through an NSF CAREER project, we are developing the bumble bee system for understanding the genetic regulation of adaptive phenotypic variation. This involves several directions:
The geographic distribution of mimicry
The genetic basis of mimicry in Western US bumble Bees
|A major research focus is in determining the genetic basis of mimetic color transitions in western U.S. bees. In the Western U.S. bees transition from a Pacific coastal color pattern to a Rocky Mountain mimetic pattern. Some species occur in only one of these zones but others cross both regions and converge onto local patterns by switching from black to red coloration. We are determining the genetic loci driving this red-black color switch in two of these species: Bombus melanopygus and Bombus bifarius. We are examining the role of these isolated loci in driving similar color switches across the bumble bee radiation. Postdoc Li Tian is performing gene expression and validation work on targeted loci. Graduate student Sarthok Rahman is performing bioinformatic analyses using GWAS to target and annotate color loci. Collaborators: James Strange, Jeff Lozier.|
Photo Credit: Sam Droege, USGS Survey
The genetic basis of yellow pigmentation in bumble bees
Bee development and pigmentation
Bee pathogens and pollinator conservation
| Bumble bee diversity has changed dramatically in the last 20 years and it is believed that one of the factors contributing to this is the spread of bee pathogens. In addition to studying the general biology and evolution of bumble bees, we seek to contribute to growing data to help determine the major factors threatening these bees. As part of this we are pursuing multiple initiatives:
1) Modeling bee pathogen epidemiology. We are performing a large scale survey in central PA to understand epidemiology of bee pathogens across time and space. This project involves cross-pathogen screens in bumble bees, carpenter bees, and honey bees across the season to understand how pathogens are shared across communities, at what scale they spread, and the role of different species in pathogen overwintering and maintenance. Funding: NE SARE grant with Briana Ezray.
2) Understanding bee virus transmission across insect communities. We are studying whether DWV and BQCV, the two most common bee viruses, can be directly transmitted between honey bees, bumble bees, and nest commensals, including hive beetles and cockroaches, using laboratory experiments. Funding: NAPPC grant with Briana Ezray.
3) Determining the factors and duration of virus persistence in the environment. We are determining how long bee viruses persist in various conditions to understand the role the timing between bee floral visitors and floral morphology may play in pathogen transmission. Funding: NAPPC grant with Briana Ezray.
4) Determining how bee virus communities change over time. We are determining changes in bee virus strains and composition in honey bee pollen over the last decade to understand how temporally dynamic these communities can be. Funding: Apes Valentes grant with Briana Ezray.
5) Landscape factors that effect bumble bee pathogen loads. As part of a large collaborative grant (funding: Foundation for Food and Agriculture Research), we are comparing the role of a variety of landscape conditions throughout Pennsylvania on the virus load and immune gene upregulation in bumble bee communities. Primary Collaborators: Christina Grozinger, Margarita Lopez-Uribe