Are populations that are well-adapted to their environment less stressed than those that are not?
Grantee: Ryan S. Mohammed
Institutions: Auburn University, United States
Grant amount: $30,374
Grant type: Seed grants
Focal species: Guppy (Poecilia reticulata), jumping guabine (Anablepsoides hartii)
Conservation status: Least concern
Disciplines: Physiology, ichthyology
Research location: Trinidad and Tobago, United States
Project summary
In this project, wild-caught guppies (Poecilia reticulata) will be exposed to an apparent threat of predation by transferring water from a tank containing a common predator (pike cichlid) into their tank. The amount of water transferred from the predators’ tank will be varied to simulate a range of predator densities. Then, cortisol levels will be measured in both the tissue of guppies and the water they are kept in. These tissue and water cortisol measurements will be compared to develop a protocol for inferring the cortisol levels of fish based on non-invasive water measurements. The researchers hypothesize that the strength of the guppies’ physiological stress response (cortisol) will vary with apparent predation risk, and they intend to eventually build on this pilot study by using the developed non-invasive protocol to compare guppies from populations the are adapted to varying intensities of predation.
Why we funded this project
This project will develop a protocol for inferring the cortisol levels of fish based on non-invasive water measurements, which should allow researchers seeking to use cortisol as a metric of physiological stress to avoid needing to kill fish in order to measure the chemical in their tissues. In terms of broader wild animal welfare theory, we also appreciate the project’s focus on the indirect effects of predator-induced fear, which are likely ubiquitous. This project is also intended as a pilot for a larger project that would investigate the impact of evolutionary adaptation to avoid predation on the stress response to the presence of predators.