Over a year ago, Rachel braved cold winds and snow to study winter insects called gallflies, winning a 2010 Young Naturalist Award for the research essay she wrote about their complex life cycles. In the summer, Rachel set out again—this time, to search cow pastures for coprophilous beetles, known commonly as dung beetles, which would become the subject of another research project.
The more Rachel learned about the dung beetle’s role in reintroducing nutrients from cow dung back into the soil, the more interested she became in the humble dung pat as an ecosystem of its own. Rachel received her second Young Naturalist Award for her investigation on the relationship between dung beetles and the height and biomass of pasture plants. She describes her process in the essay Tiny Allies: The Effect of Coprophilous Beetles on Brassica rapa and Lolium perenne Growth and Biomass.
After learning how the size of the beetle affects dung burial rates, Rachel hypothesized that larger beetles would have a greater impact on the growth and biomass of Lolium perenne, a pasture grass, and Brassica rapa, or field mustard. Experimenting with three beetle species, Rachel compared the insects’ effect on plant development with that of chemical fertilizer. She placed several of each beetle species in pots that contained soil topped with cow dung. After 10 days, Rachel removed the beetles and the remaining dung and then charted the growth of transplanted pasture grass and wild mustard for over a month, comparing the results with plants in soil that had been treated with chemical fertilizer.
While Rachel’s results did not support her hypothesis that the larger beetles would have the greatest impact on the plants’ growth, there was one unexpected finding. Rachel was the first person to identify an Onthophagus taurus beetle in Michigan. Previously, it had only been found as far north as Pennsylvania.
To encourage other young naturalists to explore the world of insects, Rachel has started an Insect Club for younger children in an urban neighborhood in Grand Rapids, Michigan. And she’s ready, dung bucket in hand, to apply what she has learned to further investigate how dung beetles could be used as an alternative to excess use of chemical fertilizers.
The Young Naturalist Awards is a nationwide, science-based research contest for students in grades 7 through 12 presented by the Museum.
The Young Naturalist Awards are proudly supported by Alcoa Foundation.