In Which I Cram Flies Into Tiny Spaces and See If They Get Nervous by Cailean Cavanaugh

Displaying anxiety in response to stressful environments is a trait that flies share with humans, so remember: if you’re ever feeling anxious, just know you aren’t alone, because a lot of flies are currently feeling that way as well.

Hello again!
​It’s Cailean, and now that you know who I am, I can skip all personal details and move on to the actual experiments.

A quick update on the effects of senna and sugar on the flies’ microbiome: there weren’t many. The flies that were fed sugar had roughly the same microbiome quantity and diversity as the control flies, while the flies fed senna had lower microbiome diversity. The differences were small, however, as were the total number of colonies. Really, this is nothing to write home about: not only because the results aren’t all that novel, but also because your family will probably think you’re weird if you choose to make fruit fly bacteria the subject of your long-awaited letter home.

Also, those flies are dead now. They outlived their usefulness, but most of them had already died anyway. 

​In another topic, have you ever been trapped in a densely-packed room, nervously waiting for a chance to leave? As tensions rise, claustrophobia sets in, and the space begins to feel smaller and smaller and… well, hopefully you haven’t been, but my flies are right now. 

The subject of my independent experiment is how living in densely populated environments affects fly mood, with a focus on anxiety and social interactions. Displaying anxiety in response to stressful environments is a trait that flies share with humans, so remember: if you’re ever feeling anxious, just know you aren’t alone, because a lot of flies are currently feeling that way as well. ​

The actual process for keeping flies in densely populated environments was fairly simple: I used more or less fly food than usual and adjusted the vial’s cap to control the height of the flies’ living space. The only problem came when I had to repeat my volume calculations three separate times because of various errors that I could have avoided if I was paying more attention. 

What proved harder was figuring out how much space to give the flies, and how much food I needed to make that space. I used a “standard” vial of flies (60 flies in 19 cubic centimeters) to calculate that the flies’ normal density is about 3 flies per cubic centimeter. This is probably one of the strangest units I’ve ever worked with, but I was able to use this average to make vials that gave the flies twice as much space, standard space, half the space, one third of the space, and one quarter of the space. After they’ve spent several days in these vials, I will test their response to the social space and centrophobism assays. 

​In the social space assay, 5 flies are placed in a small environment as tall as they are, preventing them from flying but leaving them free to walk around. Every 5 minutes, I take a picture of the flies and measure the distances in between them. The closer together they are, the happier and more sociable they are and the further away they are, the more irritable and moody they are. 

The centrophobism assay is based on the fact that fruit flies are a bunch of adorable little agoraphobes, and the more anxious they are, the more they stay away from open spaces. In this way, how often the flies cross the center of a small petri dish can act as a measure of their anxiety. 

Stay tuned to hear the amazing scientific results of putting flies in small spaces! It’s a very dense subject, but nothing to be anxious about.