stress – Anole Annals

Margaret McGrath at SICB 2020

If you look at a map of the United States at night, the urban areas are aglow with light pollution. Urban light pollution disrupts biological processes from gene expression to ecosystem composition across multiple taxa, including birds, insects, mammals, and fishes. With ever-increasing urbanization, understanding the effects of artificial light at night (ALAN) on organisms is crucial to future conservation efforts.

Margaret McGrath, an undergraduate in Dr. Christopher Howey’s lab at the University of Scranton, is examining the impact of ALAN on glucocorticoids in green anoles (Anoles carolinensis), which are commonly found in urban environments. Margaret specifically examined the impact of ALAN on the daily rhythmicity of corticosterone (CORT) and CORT responsiveness to an environmental stressor. She exposed green anoles to either a natural light-day cycle of 12 hours of light and 12 hours of dark or 24 hours of light. After six weeks of exposure, Margaret performed competitive immunoassays to measure baseline CORT levels at midnight and noon. Additionally, she measured CORT responsiveness after placing the green anoles in a bag for 30 minutes to simulate an environmental stressor.

Anoles not exposed to ALAN displayed an expected CORT daily rhythmicity with higher levels of CORT during the day than at night. Anoles exposed to ALAN lost this CORT rhythmicity and maintained CORT at a level intermediate to the other group. In contrast, ALAN does not appear to impact the anoles’ CORT responsiveness to environmental stressors. Her results suggest that green anoles exposed to ALAN are still able to respond to environmental stressors. However, there could be downstream effects from the loss of CORT rhythmicity because it has been linked to arrhythmic activity in mammalian studies.

In the future, Margaret plans to investigate if the natural CORT rhythmicity can be regained by anoles exposed to ALAN when placed back into a natural light-dark cycle. This future research can aid in determining the longevity of ALAN’s impacts on organisms. You can reach Margaret at margaret.mcgrath@scranton.edu and find more about her research on chowey.net, Dr. Howey’s website.

Victoria Pagano’s page from the crowd-funding platform Experiment

Green anoles (Anolis carolinensis) are talked about quite frequently here on Anole Annals, with 11 articles being published in 2018 and 2019 combined! As I am sure many of you are aware, green anoles change color from green to brown, and while it is known how, it is not yet known why. Although there have been multiple field studies into what causes green anoles to change color, the data have been inconclusive. This is why an experimental study is necessary to try to determine the cause of the color change.

In this experimental study, there will be two main hypotheses tested:

The first is the well known thermoregulation hypothesis. I will be testing this by establishing separate light and heat sources, and turning them on and off for different scenarios. If anoles change color for thermoregulation, then they would turn brown more frequently when the heat is off and the light is on.

The second hypothesis is the effect of increased stress. Stress will be induced by sliding a red disk towards the anoles multiple times at a high speed. Any color change that occurs within the red disk moving and the following 10 minutes will be documented as stress-induced.

I will not be able to test the advertisement signaling hypothesis due to feasibility. Because funding and space is limited, I do not have the capacity to house male anoles, as each one needs his own setup. Therefore, testing only females is the only feasible option, and by doing so, the advertisement signaling hypothesis will not be able to be tested, as this hypothesis pertains mainly to males.

To raise funding for this project, I am using an all or nothing crowdfunding platform called Experiment. As fellow anole lovers, I hope that you can help support my scientific endeavors by visiting my project page. All forms of support are greatly appreciated, from donations, to telling your friends about the project, or even by just reading my project page and commenting your thoughts! Whatever the contribution, I am very grateful, and am simply excited to be able to share what I am doing with all of you!

If you wish to learn more about this project, you can visit the project page, “What drives the color change in green anoles?”, where I have posted my methodology, protocols, and will be posting continuous updates on the progression of the project. If you become a contributor, you will have exclusive access to more updates, and will be able to learn more about the research.

My project page stops accepting donations on November 1st at 12:00 AM PT, so be sure to make your way over to the page by then to give your support!

Thank you for taking the time to read this article. I hope that you will explore the project page, and help support this cool and unique research!