Post written by Gracey Sorensen

Gracey is a rising senior majoring in Biology at Providence College and a Walsh Student Research Fellow.


Dissecting an iris to collect a pollen sample.

All organisms need proper nutrition to grow and survive. This requires interacting with the environment while being subjected to both abiotic and biotic factors, such as rain or predators. Thus, finding the right nutrients in the right amounts can be difficult. In New England, this can mean fewer nutritional resources and fewer days with optimal foraging conditions in cool, rainy spring compared with hot, humid summer. With an understanding of nutritional ecology, urban environments have the ability to support diverse insect pollinators. This requires a long-term study as well as knowledge of the nutrients provided by floral resources. 

Insect pollinators obtain nutrients from flowers—pollen provides protein and fats, nectar provides carbohydrates, and both provide vitamins and minerals. As expected, pollinator species abundance often correlates with nutritional resource (i.e. floral) availability, and enhancing floral resources can enhance survival of insect pollinators. Pollination services can therefore be constrained by lack of floral resources, or inadequate nutrition. Beyond abundance/diversity, the nutritional value of pollen and nectar provided by floral resources can be analyzed and thus, nutritional quality of these resources in urban green spaces can be quantified.

My research will build upon prior Bonoan Lab research on pollinator abundance and diversity on campus by investigating floral abundance and nutritional quality of Providence College bioswales (aka stormwater retention gardens). To survey floral abundance, I will use quadrat sampling in three bioswales here on campus. In addition, I will sample nectar and pollen from each species for nutritional analysis. Pollen samples will be analyzed for nitrogen and carbon content using Environmental Biology’s Elementar elemental analyzer (thanks, Southeastern New England Educational and Charitable Foundation!). Nectar samples will be analyzed for amino acid and sugar content using a colorimetric assay. These data will not only differentiate between the best quality plants (i.e., high levels of nutrients), but also add to the Bonoan Lab’s catalog of plant/pollinator diversity and plant-pollinator interactions on our urban campus. My data will be used to determine which plants are of best nutritional quality and allow for floral management recommendations to benefit pollinators at Providence College.

Leaf cutter bee (Megachile) collecting pollen from cutleaf coneflower (Rudbeckia laciniata) at Providence College.

Want to save the bees?

Keeping honey bees is not going to save the bees. In fact, adding more non-native honey bees to the environment may actually be harmful to our native bees. Here are three things you can do to save the bees (and other pollinators, like butterflies).

1. Plant native, blooming tress, shrubs, and wildflowers.

Diverse bloom colors, shapes, and sizes will ensure you’re providing food for diverse pollinators: bees, butterflies, hummingbirds, etc. It’s also helpful to plant flowers with a range of bloom times. This will ensure pollinators have food throughout the season. And finally, planting native is better for both you and the pollinators! Native plants are adapted to the local environment, meaning they need less upkeep on your end. They also have long-standing relationships with, and are accessible to, our local pollinators. You can find more information on what to plant in the Northeastern US from the Tufts Pollinator Initiative. The Pollinator Partnership has fantastic eco-regional planting guides for other areas/habitat types in the US and Canada.

2. Avoid chemicals.

Insecticides do not just affect pest insects, they affect pollinating insects (and other wildlife!) as well. It is especially important to avoid a certain type of systemic insecticides, called neonicotinoids. If using herbicides to kill weeds, like dandelions, remember that weeds flower too! Dandelions, clover, and other small flowering weeds are important early spring food sources for pollinators.

3. Do less yard work!

A green lawn with no flowers or habitat does not support pollinators. The “lazy lawnmower” approach (i.e., mowing less frequently) dramatically increases biodiversity of both flowers and pollinators. If you’re not into an unmown lawn, supplement your lawn with gardens along borders, in raised beds, or even in containers. In the fall, leaves and woody stems provide habitat for butterflies, solitary bees, and more! So give yourself a break, and #leavetheleaves.