Diet of Lepidophthalmus louisianensis Determined by Fecal DNA Metabarcoding

Lepidophthalmus louisianensis is a common prey to many species including stingrays, shorebirds, sturgeon, and catfish and plays a critical role in estuarine communities both through the bioturbation and aeration of sediments, as well as the creation of habitat for a number of commensal species. However, despite their importance in the estuarine environments of the northern Gulf of Mexico, the diet of L. louisianensis is currently unknown. While the literature suggests, based largely on the morphology of the mouth parts, that this species is a filter feeder, reported observations of individuals in aquaria “grazing” on their burrow walls has led some to suggest that they may in fact be “farmers” that use their feces to grow bacterial and fungi in their organic-rich burrow walls that they then “harvest”. As food availability is often a primary driver in determining growth rates, reproductive potential and population densities, knowledge of a species diet is a critical to understanding their ecology. Our primary objective is to use fecal DNA metabarcoding to determine the diet of L. louisianensis. In addition, we propose to use environmental DNA (eDNA) metabarcoding of the burrow walls and surrounding water to determine the diet and feeding ecology of Lepidophthalmus louisianensis by comparing the genetic composition of the feces to those of the burrow walls and the surrounding water. Metabarcoding of 3 genes (i.e., 16S, 18S, and rbCL) for the fecal, burrow wall, and water samples suggests a diet derived primarily by filter feeding.  

Presentation Preference: Oral

Primary Presenter: Julian Venable, Jackson State University (jvenable82@icloud.com)

Authors:

Brent Thoma, Jackson State University  (brent.p.thoma@jsums.edu)

Julian Venable, Jackson State University  (jvenable82@icloud.com)