Fruit Fly Gender as a Variable of Hypoxic Sensitivity

Friday, 13 February 2015
Exhibit Hall (San Jose Convention Center)
Jameson Jay Collier, Wayne, NE
The purpose of my experiment was to determine which gender among fruit flies was more susceptible to hypoxia. Hypoxia is defined as a deficiency of oxygen reaching the tissues of the body. Hypoxia can be induced by exercise, a medical condition, or the environment, which I am using in my experiment. There is hypoxic, which is a lack of oxygen getting to the heart or lungs, ischemic, which is the heart failing to transport oxygenated blood around the body, anaemic, which is the lack of oxygen-carrying blood cells, and histotoxic, which is blood cells not being able to take in oxygen. My hypothesis was that female fruit flies would be more sensitive to the hypoxic environment than the males. For this experiment, I relied on a hypoxic chamber I built in 2013 for the Greater Nebraska Science and Engineering Fair and the Nebraska Science Fair. The chamber had a regulated valve at the bottom through which nitrogen gas was pumped in and an outflow tube for the purged oxygen, which was forced into a bucket of water that served as a gas lock. The atmospheric environment of the chamber was monitored with Vernier sensing probes. I used this chamber to test fruit flies for hypoxic sensitivity at levels of 15%, 10% and 5% oxygen. The fruit flies were tested at these levels for one hour a day during a period of three days. Then I observed different behaviors of the fruit flies to be able to judge the effects of being in a hypoxic environment. My observations were based on cyanosis, disorientation, fatigue, and death. The gender with the highest amount of affected subjects was deemed more sensitive to the hypoxic environment, which turned out to be the male fruit flies. At 15% O2 females lost only 20% of the tested group while the males lost 56%. Females also remained more active while in the hypoxic chamber. At 10% O2 females again were less sensitive to the hypoxic environment with a 48% loss of population in females and a 98% loss in males. At 5% O2 all the fruit flies were killed, but the females were the last to die off. These results can be explained. I based my hypothesis off of human specifications, but in fruit flies, as in most of the animal kingdom, the female is bigger than the male. This research also showed that the threshold of life for fruit flies is somewhere between 10%-5% O2 which is actually quite similar to humans.