Simple Ways to Measure Behavioral Responses of Drosophila to Stimuli and Use of These Methods to Characterize a Novel Mutant

The behavioral responses of adult Drosophila fruit flies to a variety of sensory stimuli – light, volatile and non-volatile chemicals, temperature, humidity, gravity, and sound - have been measured by others previously. Some of those assays are rather complex; a review of them is presented in the Discussion. Our objective here has been to find out how to measure the behavior of adult Drosophila fruit flies by methods that are inexpensive and easy to carry out. These new assays have now been used here to characterize a novel mutant that fails to be attracted or repelled by a variety of sensory stimuli even though it is motile

Repulsion of flies by heat.

<p>A) Flies are placed near a hot plate. Data from each of the quarters are presented for every 5 minutes. Mean ± S.E.M. for 4 experiments. B) Control without heat. Mean ± S.E.M. for 2 experiments. Temperatures in each quarter are the average of 4 experiments for A and 2 experiments for B.</p

Attraction of flies to a non-volatile chemical, sucrose.

<p>Method 1: Agar throughout, sucrose in one half. Data are presented for each of the quarters. A) Flies not starved. Mean ± S.E.M. for 3 experiments. B) Flies starved. Mean ± S.E.M. for 5 experiments. C) Flies starved, control without sucrose. Mean ± S.E.M. for 5 experiments. Method 2: Sucrose with agar at end. Data are presented for each of the thirds. D) Flies not starved. Mean ± S.E.M. for 2 experiments. E) Flies starved. Mean ± S.E.M. for 4 experiments. F) Flies starved, control without sucrose. Mean ± S.E.M. for 4 experiments.</p

How to measure response to cold.

<p>Flies start out at the left end and avoid going to the cold end. Readings are in 4 parts as indicated. See text.</p

Attraction of flies to water.

<p>A) Water deprived flies are presented with water. Data are shown for each of the quarters. Mean ± S.E.M. for 5 experiments. B) Control without water. Mean ± S.E.M. for 4 experiments.</p

Repulsion of flies by a non-volatile chemical, quinine HCl.

<p>A) Flies are exposed to quinine. Data are presented for the quinine half and the half lacking quinine. Mean ± S.E.M. for 5 experiments. B) Control without quinine HCl. Mean ± S.E.M. for 6 experiments.</p

How to measure response to a volatile repellent, benzaldehyde.

<p>Method 1: A) Flies start out nearest the repellent and then run away from the repellent. Readings are in 3 parts as indicated. Method 2: B) Flies are randomly distributed at the start and then run away from the repellent. Readings are in 3 parts as indicated. See text.</p

How to measure response to gravity.

<p>Flies start in the bottom of a vertical test tube, then migrate to the top. Readings are in 3 parts as indicated. See text.</p

Attraction of flies to light.

<p>A) Light-deprived flies are presented with light. Data are shown for each of the 4 parts of the assay. Mean ± S.E.M. for 5 experiments. B) Control with parallel light. Mean ± S.E.M. for 6 experiments.</p

A mutant that fails to respond to multiple stimuli.

<p>At the right end of an 11 cm×70 cm tube were placed two repellents—benzaldehyde and high temperature (38°C)—and at the left end two attractants—light and a favored temperature (29°C). Flies were placed near the repellent end (labeled here “origin”). A) Nearly all the parental flies went to the attractant end (labeled here “furthest”). Mean ± S.E.M. for 7 experiments. B) Mutant flies failed to be repelled or attracted. Mean ± S.E.M. for 4 experiments. Details will be presented elsewhere [Vang <i>et al.</i>, “<i>Drosophila</i> mutants that are motile but fail to respond to stimuli” (manuscript in preparation, 2012)].</p