Determining the Effects of Invasive Plant Species on Soil Environments with C. elegans Chemotaxis Bioassays

Lonicera maackii is a great invader of temperate deciduous forests. Suppressive effects of native understory growth in areas inhabited by L. maackii are visible at Shelby Bottoms Greenway in Nashville Tennessee. Studies show that L. maackii impacts native understory through a combination of allelopathy and light-reduction. Quantifying allelopathy is thought to be possible via analysis of L. maackii and native-inhabited soils at Shelby Bottoms. In order to quantify differences in soil components, Caenorhabditis elegans chemotaxis assays were utilized. The natural history of C. elegans as a microbivore makes it a great candidate for soil assessment bioassays. Nematode attraction to sterile and non-sterile soils of native and invasive inhabited areas was assessed in four different bioassay treatments. Mean chemotaxis indexes (-1 < CI < 1) of four bioassay treatments were determined insignificantly different. However, the early soil collections displayed significant attraction to particular soil samples, showing that performing the experiment during the summer may result in better data. Reducing attractant variables will be necessary for future studies as well. Comparison of the attraction of C. elegans to Native-vs.-Invasive-inhabited soils may give insight for future research in ecological bioassays, nematode genomics, and soil ecology.