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Pollinator research at the Arboretum

The Arboretum at Penn State’s mission is to engage the academic strengths of the University in promoting scholarship and education about plants and their history and importance on Earth.

We recently sat down with graduate student Codey Mathis to discuss her research at the Arboretum and how it impacts our ecosystems. Here’s what she had to say:

Tell our readers about your background

Growing up, I thoroughly enjoyed playing outside in nature. I would catch all manner of insects, flip logs looking for salamanders, and dream that I was going to be the next Jeff Corwin or Steve Irwin. I followed this passion to receive a bachelor’s degree in fisheries and wildlife from Oregon State University, where I assisted in many graduate-level research projects themed around how wildlife responds to anthropogenic disturbance. One of these projects was investigating native bee communities in timber harvests, and I fell in love with the world of pollinator habitat management and conservation. Much of my research focuses on conducting applied research to inform how conservation managers and horticulturists can design better landscapes for healthier plant-pollinator communities. Additionally, I’m intrigued by how we can improve our current insect community monitoring techniques, which currently rely on lethal capture and prohibitive time-intensive identifications through the lens of a microscope. 

What research projects have you worked on in coordination with the Arboretum?

Last summer I began a project trying to determine how plant-pollinator networks empirically form. There has been a lot of modeling about these networks, and we can guess how they come together, but seeing it happen in real-time is something that’s not really been studied. The Pollinator and Bird Garden in the Arboretum was the perfect model system to study this, and with its inception last year it was the perfect time. I chose 16 plant species that will grow multiple years and monitored them throughout the summer, capturing insect visitors and cataloging the background plant and pollinator communities as well. In 2 years, I’ll repeat that study and see what has changed: basically, seeing if the same visitors are sticking to the plants they’ve visited previously, or if they will change in ways that we can predict or understand. This will help us make better decisions about what to plant.

This summer, the project I’m doing is a lot smaller scale. As a bee forages for pollen, she can either stick to one type of flower (i.e., specialize on that flower) or collect pollen from multiple species of flower (i.e., generalize). The flowers, of course, don’t want her to deviate: they don’t want pollen from five different plant species, they want it from their conspecifics. Understanding the extent to which an individual specializes, or not, and what might impact that are important drivers for plant-pollinator health, but also evolution. To study this, we’re collecting individuals with full pollen loads and DNA-metabarcoding them to assess what types of pollen she has, as well as assaying the pollen for its nutritional qualities. Along with surveys of competition and what else is blooming, this can help us understand what might drive an individual foraging bee to specialize.

A few other studies include combining artificial intelligence and computer vision to monitor insect communities; looking at what is nesting in the native solitary bee hotels and how much parasitism happens there; and looking at how the arrangement of plants impacts pollinator visitation.

The Arboretum is lovely because it marries science and aesthetic beauty into a functional space. Whether you want to come and learn something or just want to sit and watch the goldfinches eat seeds off the Echinacea, you can do that. It is a lovely multi-use space. I know that the research that I’ll conduct here will also inform future management of the Arboretum and by conducting it there, I have an avenue to disseminate the information that I’ll learn. 

Why is studying pollinators important?

Pollinators are so named because they provide us with the ecosystem service of pollination, free of charge. Over 80% of wild flowering plants rely on pollination for successful fruiting, and around 75% of our crops also rely on this invaluable service. While bees are the most efficient pollinators because of their hairy bodies and tendency to visit the same types of flowers, other pollinators include flies (specifically flower flies), butterflies, moths, wasps, and beetles. It is well understood among entomologists that insect populations are on the decline, though the reasons why vary by species. For pollinators in North America, it’s undeniably about pesticide use, habitat loss (aka loss of forage), and climate change. If we can better understand what drives the everyday choices of these insects, we can make informed management decisions that can halt, and perhaps reverse, their declines. 

What is a plant-pollinator interaction and how we can look out for this in our daily lives?

A plant-pollinator interaction is exactly what it sounds like: when a plant and a possible pollinator interact! More specifically, it usually refers to when a pollinator is on or near the flowering structure of a plant. Usually, they are here to acquire the resources that these plants provide: nectar (for carbohydrates) and pollen (for proteins and lipids). When they interact with these components of the plant, it is likely (though not guaranteed) that pollination of the plant can occur. To see plant-pollinator interactions, you simply need to sit by a flower and watch it for a short period of time, particularly on days that have weather that is good for pollinator activity (i.e., above 60 degrees Fahrenheit, low wind, no rain, minimal cloud cover). 

How can we increase pollinators in our own gardens?

Insect pollinators are mostly declining because of lack of available forage and pesticide use. To provide a good area for insects in your yard, you could minimize the use of broad-spectrum pesticides and make sure that you have a variety of plant species in your yard. You want to make sure you have species of flowers that bloom across the entire growing season — only having spring ephemerals makes your yard a desert for pollinators that are active in the summer. You can also construct or purchase a bee hotel and place it in your yard to provide an area for wood-nesting insects to stay (though be sure to maintain it to avoid the spread of disease and parasites)!

How do you want visitors to the Arboretum to think about your research?

I want folks to know that the research that is being conducted in the Arboretum goes back to the community. The research that I conduct is very applied and can benefit not only conservation entomologists and horticulturists designing huge landscapes, but also folks in their backyard. From my research last summer, I learned what plants are the most attractive to a variety of insects (Pycnanthemum muticum and P. virginianum for bumble bees, honeybees, and some pretty cool wasps; Euthamia graminifolia, Eupatorium perfoliatum, and Lythrum alatum for a wide diversity of bees, wasps, and flies; Liatris pychnostachya for butterflies.). The research I’m conducting this summer will let us know how to arrange your plants to best provide for the health of the pollinators and reproduction of the flowers. I also strive to make my research approachable and disseminate it into the community by participating in outreach events like OLLI Day and the Pollination Celebration. 

Learn more about The Arboretum at Penn State