Feb 25, 2022

Public workspacePredation selection trial protocol

This document is a draft, published without a DOI.
  • 1National Centre for Immunisation Research and Surveillance;
  • 2University of Michigan - Ann Arbor
Kira Monell
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Document Citation: Laura Lopez, Meghan Duffy 2022. Predation selection trial protocol. protocols.io https://protocols.io/view/predation-selection-trial-protocol-b5m8q49w
License: This is an open access document distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Created: February 25, 2022
Last Modified: February 25, 2022
Document Integer ID: 58784
Abstract
This is a protocol to determine if Chaoborus preferentially feed on infected or uninfected Daphnia.
Predation Selection Trial Protocol
L. K. Lopez

Purpose: To determine if Chaoborus preferentially feed on infected or uninfected Daphnia

1. Rear Mid-37s in 150 mL beakers filled to 120mL with filtered lake water at a density of 20 animals (age 0 days) per beaker.
2. At 9 days of age, expose half of the beakers to Metschnikowia spores at a concentration of 200 sp/mL
3. Expose the control beakers to the same volume of liquid as the infected beakers, but milliQ water.
4. 10 days following exposure to spores (19 days of age) check animals for infection
5. Conduct selection trials when Daphnia are 19 days of age (10 days following spore/milliQ water exposure).
6. On day of trial set-up, photograph a subsample of the infected and control animals for later body size measurements.
7. In clean 150 mL beakers filled to 120 mL, place 10 control (uninfected Daphnia) and 10 infected Daphnia in each individual beaker
8. Add one Chaoborus (preferably 4th instar, but otherwise 3rd).
9. Place beakers in incubator at 20C and leave in the dark for 24 hours.
10. After 24 hours, remove Chaoborus and after examining daphnia under the microscope, identify how many infected and uninfected animals remain alive. Record this data.
11. Goal replicate number: minimum 10, preferably 20.
12. Use data to calculate Chesson’s alpha
13. Photograph Chaoborus and subsample of Daphnia used in the experiment to account for differences in predator gape size and prey size.