Jenna Walters’ research explores impacts of extreme heat on blueberry pollination

Mallory Marienfeld<fourni49@msu.edu> - February 28, 2021

Graduate student Jenna Walters shares her passion for entomology and insect photography, and her research on the impacts of extreme heat on blueberry pollination.

Name: Jenna Walters

Hometown: Clarkston, Michigan

Previous education: BS in environmental biology/zoology with a minor in entomology at MSU

Major professor: Rufus Isaacs

What are you researching?

My research is focused on understanding the impacts of extreme heat on blueberry pollination. Specifically, I seek to understand the impacts of extreme heat on the reproductive functioning and output of blueberry plants and their native bee pollinators.

For some context, wild blueberries are native to Michigan, and these wild blueberries have been used to cultivate blueberry crops, which are managed in agricultural landscapes. Michigan is a leading producer of northern highbush blueberries, yielding about 100 million pounds every year. This yield is largely attributed to blueberry pollinators, both wild and managed, who perform the very necessary service of pollination.

Miner bee — A miner bee, Andrena carlini, covered in pollen visiting a blueberry flower at MSU's Trevor Nichols Research Center in Fennville, Michigan. This native bee vibrates their wing muscles to release blueberry pollen from the flower, making them efficient blueberry pollinators. Photo by Jenna Walters, MSU Entomology.

When a bee visits a blueberry flower, they push their heads inside it to reach nectar stored at the base of a flower. As they push themselves into the flower, they bump up against the stamen, or the male part of the flower, and the style, or the female part of the flower. Pollen is then released from the tip of the stamen, or the anthers, which collects on the furry body of a bee. This pollen is groomed by the bee, packing it onto themselves to transfer back to their nest. As a bee visits different flowers, a little bit of pollen is transferred to the sticky stigma on the flower style, and thus pollination has occurred. Pollen serves a critical role for the productivity and reproductive output for both the plant and the bee. For the plant, once pollen is placed on the stigma, germination occurs and pollen tubes travel down the flower style to fertilize it, which turns into seeds. The greater number of fertilized seeds in a blueberry, the bigger it is. For the bee, pollen is the primary resource of protein and lipids for bees. A nutritious pollen diet during larval development leads to larger, healthier and more resilient bees.

So, what happens if that pollen is exposed to extreme heat? As climate change intensifies, extreme heat events have increased in duration, frequency and intensity. This is true globally, including Michigan. In 2018, an extreme heat occurred during blueberry bloom, and we saw a 30-million-pound loss in yield compared to the previous year. It’s uncommon for heat extremes to occur in Michigan during spring, so this phenomenon was totally unexplored. We know even less about how that heat wave could have affected bee development, health and subsequent populations. By uncovering the ways heat affects blueberry pollination systems, we can create strategies to protect them as climate change continues to intensify.

Why study entomology?

Insects are incredible! They have been stewards of the land long before humans, with fossil evidence suggesting insects living on Earth around 479 million years ago. Insects also have the largest biomass of terrestrial animals, with an estimated 10 quintillion individual insects alive at any time, which means there are 200 million insects for every one human. Insects have shaped the way people live, the foods we eat and the landscapes we live in. The history and influence of insects is incredibly important to understand, yet still so many unknowns remain. It’s exciting to be a part of a field that has so many mysteries to uncover.

What or who inspired your interest in entomology?

I found my passion for entomology as an undergrad working in Zsofia Szendrei’s lab. At the time, I didn’t consider entomology as a career path, but wanted to have a paid summer job doing research and was lucky enough to be hired. I worked with Adam Ingrao looking at biocontrol strategies for asparagus pests and during our long three hour drives to the field, Adam and I would talk insects and ecology.

"I started to learn how connected the world was by insects, and everything just clicked. I haven’t looked back since!"

What is your favorite activity or responsibility as part of your graduate studies?

There is nothing better than summer field work! After working on writing and data analysis all winter, it’s exciting to work outside conducting experiments.

What is your favorite thing about MSU?

The community of students, scholars and mentors. The people make the place!

What is your favorite insect and why?

My favorite insect is the golden northern bumble bee, or Bombus fervidus. This bee is native to Michigan and is super fuzzy with a golden abdomen. I see them less frequently than other bumble bee species in Michigan, so it’s always exciting to see them in spring.