Understand Insects; Understand the Ecosystem

The next time you are on a nature trail or an urban sidewalk and are tempted to squash a bug on your path, consider the cost. Are you helping? Are you hurting? Assistant biology professor, ecologist, and entomologist Ellen Yerger shows her students the scientific value of insects, how they help humans, and the ecosystem's interconnectivity.

Why is studying insects important?

Insects are important components of most ecosystems. There has been a lot of information about the crucial role of pollinators in producing our food. Basically, fruits and vegetables must be pollinated, and most pollinators are insects, like bees, flies, and butterflies. In contrast the pollen of grains (wheat, corn, rice) is carried by the wind.

Growers have always known how important pollinators are. For example, I took my entomology class to a nearby family farm of one of our biology graduates. When he added just two honeybee hives on the farm their squash yields increased so much, they couldn't get in between the rows to harvest them in their usual way. Now they plant the rows further apart. There have been controlled studies supporting this effect, that with no other changes, having more pollination increases farm yields.

Ellen Yerger in her lab

Other insects eat leaves, roots, and fruits of plants. When they are out of balance with their ecosystem, these insects are pests. They cause a great deal of damage to crops and natural ecosystems. Most entomologists work at controlling these pests, and to do this effectively it is important to understand the insect's biology. We study factors like the insect's timing, when they are active, how many generations a year, how temperature might suppress or amplify their populations, their movements, what predators might control them, what diseases might suppress them, and what other plant species they live on. This type of knowledge allows entomologists to make more effective controls for pest insects. The odd part is that we study insects so we can kill them more efficiently, which is maybe not intuitive.

Ellen Yerger holding a chickadee

More About Ellen Yerger

  • Postdoctoral Scholar, Pennsylvania State University
  • PhD, Entomology, University of Illinois, Urbana-Champaign
  • MS, Chemistry, University of Illinois, Urbana-Champaign

Courses Yerger Teaches

  • BIOL 201 Ecology and Evolution
  • BIOL 202 Cell and Molecular Biology
  • BIOL 203 Genetics and Development
  • BIOL 240 Human Physiology
  • BIOL 420/520 Entomology Principles and Practice
  • BIOL 681 Contemporary Environmental Concerns

Why is it important to have women involved in entomology and other natural sciences?

Ellen Yerger and a student gathering samples in Duff Park True diversity is diversity of thought. The ideas scientists have are based on our learned experiences. The more diverse our outlooks, the more novel perspectives we bring to the conversation. We need the talents of all of us, not just half of us, to address the challenges we have.

There are a lot of social factors that affect how we work together. These need to be recognized more intentionally by scientists so we remove unneeded barriers to underrepresented groups.

Some of your research focuses on invasive plants impacting insect populations. Usually, it's the other way around—we hear about insects affecting plants. What's this about?

Well, some insects are beneficial. The aspect that I'm studying is their role in the food web, how insects provide a key link in transferring energy from plants to predators. The sequence is this—plants gather energy from the sun through photosynthesis, insects eat the plants, and predators eat the insects. One predator we care a lot about is birds. How much do certain plants feed insects that feed birds?

What's the best thing students learn in your classroom?

IUP Student Assistance Fund The most important thing I teach my students is how to think like a scientist. Scientists use data to draw conclusions and create knowledge. Thus, their decisions are data based. The data is gathered from the scientific process, which is a sequence of steps, starting with an observation, asking a question about it, proposing an explanation, and testing that explanation with an experiment that uses controls as checks. Students learn this scientific process best in hands-on laboratory situations, which we emphasize in our courses at IUP.