Metagenomic Analysis of Mysis Gut Contents

Session: 54. - Food Web Ecology and Dynamics of Lake Ontario: Nearshore ? Pelagic Linkages

Toby Holda, Cornell Biological Field Station, [email protected]
Matthew Hare, Cornell University, [email protected]
Lars Rudstam, Cornell University Bio Field Station, Dept. of Natural Resources, [email protected]
Brian Weidel, U.S. Geological Survey, Great Lakes Science Center, [email protected]

Abstract

Mysis diluviana are omnivores in the Great Lakes. Gut microscopy and gut fluorescence indicates high herbivory rates in both juvenile and adult M. diluviana in Lake Ontario. However, microscopy is limited to detecting diet items with hard structures, fluorescence is unable to determine genera of phytoplankton, and neither method can determine relative contribution of phytoplankton and zooplankton in diets. We tested application of an 18S ribosomal DNA metabarcoding marker for eukaryotes to determine: 1) if the marker could detect expected diet items of mysids when applied to wild-caught mysid stomachs, and 2) the degree of quantitative correlation between 18S sequence read counts and feeding rates on two prey types (cladocerans and copepods) in several experimental diet manipulations on captive, starved field-caught mysids. M. diluviana were collected from southeast Lake Ontario in July, August, and November 2016. Gut contents were dissected out of mysids and different subsampled individuals per sample were analyzed with microscopy and metabarcoding. Genetic analysis detected diet items of taxa known to be important in the mysid diet, and also some taxa not recorded previously. Results from lab experiments will give information on the uncertainties associated with metabarcoding analyses of diets in invertebrates.

1. Keyword
genetics

2. Keyword
diets