Week two and three--The staging process and the Y-maze experiment

Hello Everyone. My name is Sandra Ho and I am writing about my second and third week in the Evolution and Behavior Lab at Harvard University.

My second week was quite easy and simple. On the first two days I created more enriched and standard tubes for all types of flies for trials, which included: Canton.S and DGRP( include 45,105, 796 and 535). The flies in DGRP are not genetically identical as some of them exhibits higher variability and some of them exhibits lower variability. During the middle of the week, I noticed a lot of the flies in the trial tubes started to hatch. Ben suggested me to put them in the staging tubes for five days and then they would be available to test for behavior. I put 10 male and 10 female in each of the enriched tubes and 20 males or 20 females in each of the control tubes for staging. He also gave me a suggestion for my project: collect flies in outdoor by using traps. He thought it was a good idea to test them because those flies are wild types and the environment they used to live is a lot different from the flies in our lab, hence the results might be different. Therefore, I made five traps( put a paper funnel in the opening of the test tube which contains fly food) and put them behind a bush near my dorm.

The third week I finally got the chance to do the Y-maze experiment! Basically, the Y-maze experiment is to quantify left and right turning of the flies. An individual fly is placed in a Y-shaped maze on top of a light box, allowed to walk freely for two hours, and the X-Y position of the fly’s centroid  is tracked by a camera. The first thing I had to do was to make the flies asleep by using CO2 gas and use a brush to put them into a tray that consist of 120 individual Y-mazes. One fly in each maze and each maze is covered by a lid.This set up allows 120 flies to be run in parallel, and each of which makes hundreds of turns during the two-hour experiment Then I had to put the tray inside the light box and put all the information of the flies in the computer that is connected to the light box. And finally, when I clicked the button "Start Data Collection", the computer would then start collecting data!

This is the light box used for the Y-maze experiment.

This is the computer that is used for data collection.

And those are my trials and stocks of flies.

For the coming week, I will start analyze the data with Ben because there are soon enough flies that have been tested for behavior. I am really excited about it and I hope everyone is doing well in their lab too!