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SAMPLE LAB REPORT

Perception of Different
Sugars by Blowflies by Alexander Hamilton

Biology 101
October 24, 2009

Lab Partners:
Sharon Flynn,
Andi Alexander

Fly
lab
report
p.


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ABSTRACT
To feed on materials that are healthy for them, flies (order Diptera) use taste receptors on their tarsi to find sugars to ingest. We examined the ability of blowflies to taste monosaccharide and disaccharide sugars as well as saccharin. To do this, we attached flies to the ends of sticks and lowered their feet into solutions with different concentrations of these sugars. We counted a positive response when they lowered their proboscis to feed.
The flies responded to sucrose at a lower concentration than they did of glucose, and they didn’t respond to saccharin at all. Our results show that they taste larger sugar molecules more readily than they do smaller ones. They didn’t feed on saccharin because the saccharin we use is actually the sodium salt of saccharin, and they reject salt solutions.
Overall, our results show that flies are able to taste and choose foods that are good for them. INTRODUCTION
All animals rely on senses of taste and smell to find acceptable food for survival.
Chemoreceptors are found in the taste buds on the tongue in humans (Campbell, 2008), for example, for tasting food. Studies of sensory physiology have often used insects as experimental subjects because insects can be manipulated with ease and because their sensory-response system is relatively simple (E. Williams, personal communication). Flies are able to taste food by walking on it (Dethier, 1963). Hollow hairs around the proboscis and tarsi contain receptor neurons that can distinguish among water, salts, and sugars, and flies can distinguish among different sugars (Dethier, 1976).