CENTENNIAL HONORS COLLEGE
Western Illinois University
Undergraduate Research Day 2015
Poster Presentation
How Many Parasites Are There? A DNA Analysis of “White Grub” in IL Fishes
Tori Worthen
Faculty Mentor: Shawn Meagher
Biology
In my research, I will examine species diversity in the fluke, “white grub” (Posthodiplostomum minimum
centrarchi), which has been found in the organs of four fish host species that live in Spring Lake, IL,
including bluegill (Lepomis macrochirus), green sunfish (L. cyanellus), white crappie (Pomoxis
annularis), and largemouth bass (Micropterus salmoides. Data suggests that there are big size differences
among white grub from different host species. The morphological differences in the white grub could be
caused by the development within the different host species. The purpose of this research is to use DNA
analysis to discover how many different lineages of white grub are living within four different fishes in
Spring Lake. I hypothesize that after using DNA analysis, I will determine that there are two different
white grub species infecting the organs of the fish species within Spring Lake. I will sequence
mitochondrial DNA in cytochrome oxidase I (COI), the barcoding gene for flat worms. The number of
white grub species in Spring Lake from different fish hosts will then be able to be determined by
evaluating fluke sequences that differ by <5% to be members of the same species, while those that differ
by >15% to belong to different species. The results of this research will be the first to state whether the
parasitic white grub, are separate species or one species.