A high-throughput method to quantify feeding rates in aquatic organisms: A case study with Daphnia

Food ingestion is one of the most basic features of all organisms. However, obtaining precise — and high-throughput — estimates of feeding rates remains challenging, particularly for small, aquatic herbivores such as zooplankton, snails, and tadpoles. These animals typically consume low volumes of food that are time consuming to accurately measure.

We extend a standard high-throughput fluorometry technique, which uses a microplate reader and 96-well plates, as a practical tool for studies in ecology, evolution, and disease biology. We outline technical and methodological details to optimize quantification of individual feeding rates, improve accuracy, and minimize sampling error.

This high-throughput assay offers several advantages over previous methods, including: i) substantially reduced time allotments per sample to facilitate larger, more efficient experiments; ii) technical replicates; and iii) conversion of in vivo measurements to units of carbon (mg dw L-1), which enables b...