Straightforward Assay for Quantification of Social Avoidance in Drosophila melanogaster
December 13th, 2014
Here, we present a protocol to quantify the avoidance of stressed individuals. This paradigm is powerful yet user-friendly and can be used to assess the influence of genes and environment on one kind of social interaction in Drosophila melanogaster.
The goal of this procedure is to quantify the response of flies to the social signal emitted by stressed individuals. This is accomplished by first collecting, responder, and emitter flies no more than two days before the experiment. The second step is to transfer both emitter and responder flies to fresh vials two hours before the experiment and let them habituate to the environmentally controlled room where the assay will be performed.
Next, the responder flies are placed in the TMAs and given the choice between a vial in which flies have been previously stressed, thus containing the drosophila stress odorant and a fresh vial, the final step is to count the number of responder flies in the fresh vial in the DSO vial and in the elevator to quantify their response to the DSO. Ultimately, the T maze is used to measure the avoidance by flies of a social stress signal, specifically the gilo stress odorant. I first had the idea for this method when I was a postdoc at Caltech.
At that time, Greg Sue and his postdoctoral advisor David Anderson, were inter in studying fear or social avoidance in Phyla, but there was no existing assay for that. They approached me because I was performing a lot of behavior assays in S brands'lab and while performing photo taxi and olfactory learning experiments, I had noticed that flies were attracted to vials in which other flies had spent some undisturbed time while avoiding vials in which flies had been stressed at that time with an electric shock.Bishop. Demonstration of this method is critical as the experimental process of the social avoidance assay requires some practice to be quick and efficient in transferring the bios without losing any flies or DSL.
The main advantage of this technique to examine social interactions over existing methods like computer assisted video tracking, is that this is an assay easy to master and implement, but is very powerful to quantify the social avoidance of stressed individuals. To begin the experiment, cut a porous polyethylene sheet to cover a 12.7 centimeter by 10.2 centimeter box. Fill the box with crushed ice and cover it with the sheet to complete the drosophila cold anesthesia apparatus.
Perform the experiment on a bench covered with a white bench cover and a whiteboard in front to ensure homogenous lighting conditions. Next, prepare the vortex fly aspirator teammates apparatus, thermometer, and timer. One to two days before the experiment colon anesthetize flies.
Transfer the flies with a funnel into a 50 milliliter tube and place the tube into an insulated ice bucket under ice level. Wait five minutes for the flies to enter a chill coma. Then transfer the flies onto the porous polyethylene sheet at room temperature and sort out responder flies under a stereo microscope.
Separate three to seven day old male flies from female flies, and maintain these flies in a group of 40 gently collect mixed sex Canton s emitter flies. Using a mouth aspirator allow the flies. One night of recovery to minimize any confounding effect of the collection on behavior.
Next, open the bag of test vials to replace the stale plastic smelling air in the bag with fresh air. Before the experiment, ensure that the test room temperature is at 25 degrees Celsius, that the room has even light, and that the humidity is greater than 30%Two hours prior to the experiment transfer the responder and emitter flies into fresh food vials and allow the flies to adjust to the environment on the bench where the experiment will be performed. Place the tea maze on the pounding pad and tighten the screw clip so the elevator is stable.
Next, transfer the responder flies to a fresh test vial and snap the vial containing the responder flies on top of the tea maze. Then slant the tea maze apparatus and tap it on the pounding mat so the fruit flies fall in the elevator. Move the top part of the elevator down to place the flies between the top and the bottom sections of the TMAs and make sure the elevator is above the choice point to prevent flies from escaping while the responder flies are adjusting to the new environment.
Place the emitter flies in a fresh test vial and top it with a piece of cotton. Agitate the vial on a mini vortex in this manner. The flies will emit DSO transfer the flies into a food vial and quickly place the DSO filled vial into one of the two sides of the team.
A alternate the side of placement for the DSO filled vial. In each new run, place a fresh test vial on the other side of the team A then bring the elevator completely down so the fruit flies can choose between the fresh test vial and the DSO filled vial. Immediately start the timer.
After one minute, move the elevator up to separate the flies in the fresh vial and the DSO vial from the flies stuck in the elevator. Count the number of flies in each vial and in the elevator. Repeat this.
For each genotype and or condition group size of responder flies does not influence their avoidance of DSO. After performing the experiment on a range of 10 to 80 flies, a T-test showed no statistical significance amongst the performance indexes or PIs of the responder flies. The number of emitter flies impacts the fliess avoidance of DSO as demonstrated by this graph, which represents different trials.
Using 10 to 160 emitter flies each. A substantial avoidance was still detected with only 10 stressed flies. The choice, time, and genetic background of fruit flies affect the response to DSO as demonstrated by this graph, which illustrates a response of Canton s and Elwood strains.
Both genotypes display a stronger avoidance of the DSO than Oregon and some markin strains After its development. This technique paved the way for researchers in the field of neuroscience to identify the neuro circuit underlying the perception and avoidance of CO2, one of the components of the DSO. It has also been used to study the role of autism candidate genes in affecting social behavior.
In Joseph Ano Gaster. Once mastered, this technique can be performed in less than five minutes per replicate. After watching this video, you should have a good understanding of how to conduct a social avoidance assay from the preparation of the emitter and responder flies prior to testing them to the generation of the DSL field bios and the manipulation of the teammates to provide the responders with a binary choice.
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Overview
This protocol quantifies the avoidance behavior of Drosophila melanogaster in response to social signals from stressed individuals. It effectively assesses the impact of genetic and environmental factors on social interactions.
Key Study Components
Area of Science
- Neuroscience
- Behavioral Biology
- Genetics
Background
- Understanding social interactions in Drosophila is crucial for studying behavioral responses.
- Stress signals can influence the behavior of both emitter and responder flies.
- This method allows researchers to explore the genetic and environmental influences on social behavior.
- The T maze setup is a novel approach to measure avoidance behavior.
Purpose of Study
- To quantify the response of flies to social stress signals.
- To investigate the effects of stress on social interactions in Drosophila.
- To develop a user-friendly protocol for behavioral assays.
Methods Used
- Collection of responder and emitter flies prior to the experiment.
- Habituation of flies in a controlled environment before testing.
- Use of T maze to assess avoidance of stress odorants.
- Counting responder flies in different vials to quantify responses.
Main Results
- Responder flies showed a measurable avoidance of vials containing stress signals.
- The protocol effectively distinguishes between responses to stressed and non-stressed flies.
- Results indicate significant behavioral changes in response to social stress signals.
Conclusions
- This protocol provides a reliable method for studying social interactions in Drosophila.
- Findings contribute to understanding the genetic and environmental factors affecting behavior.
- The T maze approach can be adapted for various behavioral studies.
Frequently Asked Questions
Executive Industry Relevance
This assay enables high-throughput quantification of social avoidance behavior in Drosophila, providing a genetically tractable model for de-risking target validation in neuropsychiatric drug discovery. By linking genetic and environmental modulation to measurable behavioral outputs, it supports early-stage mechanistic screening for compounds affecting social cognition pathways. The low-cost, robust design facilitates scalable screening of mutant libraries or environmental conditions relevant to social deficit phenotypes.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of genetic contributions to social behavior phenotypes through strain-specific avoidance responses.
- Operational Value: Supports functional validation of candidate genes by quantifying avoidance as a phenotypic readout.
- Predictive Value: Facilitates target de-risking by establishing dose- and genotype-dependent behavioral responses to social stress signals.
Screening & Assay Development
- Scientific Value: Provides a quantitative, binary-choice readout suitable for screening genetic or pharmacological modulators of social avoidance.
- Operational Value: Enables assay standardization through controlled emitter/responder ratios and environmental habituation.
- Scalability: Compatible with multi-genotype screening due to short duration (<5 min/replicate) and minimal equipment needs.
Translational & Preclinical Research
- Translational Relevance: Connects Drosophila social avoidance mechanisms to conserved pathways relevant to human social cognition disorders.
- Preclinical Continuity: Supports cross-species validation by measuring conserved behavioral responses to stress-induced chemical signals.
- Biomarker Alignment: Enables correlation of genetic background with avoidance phenotypes for target prioritization.
Pipeline & Workflow Integration
The assay fits within early discovery workflows, supporting hypothesis testing in target validation and enabling scalable screening prior to lead identification efforts.
- Discovery Biology: Supports mechanistic de-risking by quantifying avoidance behavior as a function of genetic and environmental variables.
- Screening: Delivers reproducible, quantitative outputs for comparing responder performance across conditions.
- Analytics: Generates performance indices (PIs) enabling statistical comparison of avoidance strength between genotypes.
- Translational Research: Aligns with phenotypic screening for social deficit models via conserved stress-response pathways.
- Enterprise Reuse: Reusable across projects studying social behavior, stress reactivity, or neuropsychiatric target validation.
Operational & Enterprise Impact
- Scientific Value: Reduces mechanistic ambiguity in social behavior studies through quantifiable, genetically modifiable avoidance responses.
- Operational Value: Ensures reproducibility via standardized habituation, emitter titration, and blind counting procedures.
- Strategic Value: Improves go/no-go decisions by providing early phenotypic evidence of target engagement in social circuits.
- Portfolio Impact: Enables risk-adjusted advancement by identifying modifiers of social avoidance with high predictive confidence.
Implementation Considerations
- Requires expertise in Drosophila handling, sex separation, and behavioral assay execution.
- Depends on controlled environmental conditions (25°C, >30% humidity, uniform lighting) for reproducible results.
- Necessitates standardization of emitter fly numbers and stress induction protocols across runs.
- Adaptation to alternative genotypes requires validation of baseline avoidance performance.
- Limited to measuring avoidance; does not capture approach or other social interaction dimensions.
