Update 2020: for all further blog posts, please visit my Medium blog (https://medium.com/@lilawestreich). I’ll be posting articles and updates there for the foreseeable future. Thanks for your interest!
There are very few times in my life when I am actually asked what I study while riding in an elevator. However, I have absolutely perfected my ‘elevator pitch,’ both on the off-chance that someone finally catches me going up to the 5th floor of my therapist’s office and asks me what I do, or to rattle off to anyone who asks at a party.
I want to break down my project into bite size pieces, short blog posts just long enough to get your feet wet without dunking you into the ocean of my work. Especially since much of what I do revolves around high-level genetics, bioinformatics, and ecological concepts. This way, I can give you the background you need to understand my dissertation work and experiments, and slowly introduce you to some of the more exciting preliminary results. Maybe we’ll both learn something!
Introduction — Background in PNW Pollinators
Most of pollinator ecology work in the last few decades has consisted of diversity assessments. Scientists go out into the field with a net, a few thousand collection jars, and a notebook, and collect anything and everything that buzzes past their head for a few hours a few times a year. They bring home the insects they collected in vials, stick them in the freezer to kill them, and then pin them to a board and use every guide imaginable to identify each insect to species level.
This process works! It’s a heck of a lot of work, and identifying species takes a lot of learned skill. But it yields a wealth of information about what species are present on different landscapes, their relative abundance, and the total number of pollinators in any one area.
Four years ago, when developing my project, I decided I didn’t want to go the diversity assessment route. My reasoning was rooted in both laziness — it’s a lot of work, and learning identification is an entire PhD project in and of itself — and my interest in working solely with native bees. I researched native bee breeders in Washington State, and found multiple breeders of Osmia lignaria, the Blue Orchard Mason bee, a native bee in the PNW and across the west coast.
Mason bees are a very simple, friendly creature. They don’t contain venom, nor do they have a stinger. They are a solitary species, meaning that instead of a hive full of sterile female workers and a single fertile queen, each individual female Mason bee is able to produce offspring. Female Mason bees are large and dark, almost as big as bumble bees, with a resemblance to flies. Male Mason bees are smaller, and full of tufts of yellow fuzzy hairs, with a yellow strip of hair on their head.
Almost immediately, I fell in love with Mason bees. They were gentle and cute, they buzz around your head when slightly bothered, and they seemed to have tiny personalities of their own. They over-wintered — another version of hibernation, for insects it involves a cold period of slowed heart rate and energy usage until the weather warms — in the form of tiny brown cocoons (pupae) that resemble moldy coffee beans. I was hooked.
Mason bees are generalist foragers, meaning they visit a whole range of different flowers from varying families and genera. They’re not picky. They’ll visit invasive plant flowers that share no evolutionary history with their lineage, and native plant flowers that have been around as long as they have, historically-speaking. This makes them a useful model species for studying how foraging patterns — which plants they visit, how often, which plants they prefer — are shifting and changing as our landscape becomes more filled with invasive species and horticultural plants in gardens.
Seattle is a strange place. We have an extremely diverse range of species growing here. If you were to throw a stone from a hundred miles above the city, the chances that it would land close to both a famous northwest native tree like a Douglas Fir and an Argentinean Monkey Puzzle tree are about equivalent. Front yards are filled with trees, shrubs, and small flowering plants from the likes of France, India, China, Chile, and South Africa, among many others. The Washington Park Arboretum features entire sections devoted to different parts of the globe, but you’d be just as likely to find some of those Arboretum species in a retiree’s front lawn in West Seattle. We are a diverse and unique city.
Because our landscape mosaic is so unusual, the green spaces within the city are very different from one another. Some public parks, such as Magnuson Park, were developed on top of old landfills and are filled with invasive species. Others, like Seward Park, contain some of the oldest old-growth forest in the city and have never been developed. The wide range of restoration across the parks interested me as I began to develop my thesis. How would bees change their flower visits in Magnuson Park in comparison to Seward Park? Would changes in the landscape lead to changes in foraging? Did bees prefer some flowers over others, no matter the landscape? And where, exactly, were they going?
And so, an experiment emerged. What if I placed bees in each of these different parks, collected data on what plants were available to them, and collected pollen from the bees once they had created their nests? I could sequence the pollen using my genetic background from my undergraduate degree in plant breeding & genetics, and identify the plants they visited at different relative frequencies. Then I could compare their flower visits to their overall success rates at each of the sites.
And here I am, still going strong with 24 sites across Seattle, not four years later.
Next, I’ll talk in-depth about the life cycle and habits of Blue Orchard Mason bees, and a little more on the genetic sequencing performed by our lab. Until then!
Westreich L., Tobin P.C., Bakker J. Effect of floral resources on Osmia lignaria. Orchard Bee Association Conference. 2018. UC Davis, CA.
Westreich L. Tobin P.C., Bakker J. The effect of floral resource composition on the native solitary bee Osmia lignaria Say in western Washington. Entomological Society of America Conference. Vancouver, BC.