We wish to thank Brian Shepherd, Tat Udomritthiruj, Aaron Willey, Ruby Froom, Elise Pitmon, and Rose Hedreen for early work in testing and establishing this methodology and chamber designs. We thank Kelly Tellez and Graham Buchan for reading and editing the manuscript. We thank Andrew Seeds and Julie Simpson for their pioneering work and their advice and support in suggesting the use of Brilliant Yellow Dye (Sigma).&#160;This work is supported in part by the Mary E. Groff Surgical and Medical Research and Education Charitable Trust, the Bronfman Science Center, and the Hellman Fellows Program.

1. Preparation
<ol>
	<li>Prepare an aspirator for moving live Drosophila from a culture vial to the grooming chamber. Aspirators allow transfer of conscious animals to the behavioral chambers to ensure that anesthesia does not affect subsequent behavioral observation.
	<ol>
		<li>Using scissors cut 1.5 feet of tygon tubing ID &#8539;&#34;, OD &#188;&#34;.Cut at least 1 inch off of the tip of a 1 mL disposable micropipette tip. Hold a 1 cm square piece of mesh (opening 0.196 inch) over the cut tip. 
		NOTE: Most 1mL tips have a gradation line where the tip sits in the package box, typically cut to that line.</li>
		<li>Snugly place a fresh 1 mL micropipette tip over the mesh/cut tip. Observe the mesh form a tight barrier between the two tips. The inside of the new tip creates a holding chamber for flies.</li>
		<li>Cut the extreme tip of the new micropipette tip to widen the opening enough to allow passage of a single fly. The hole will roughly match the opening of the grooming chamber (approximately 1.5-2 mm in diameter).</li>
		<li>Snugly fit the nested tips onto the end of the tygon tubing. Push the tips into the tube to ensure a tight fit to allow for vacuum pressure.</li>
		<li>On the other end of the tubing, cut the tip of a 200 &#956;L micropipette tip and fit the narrow cut end into the tubing. This is the &#34;mouth&#34; side of the aspirator.</li>
	</ol>
	</li>
	<li>Prepare dust aliquot tubes. Weigh approximately 5 mg of Brilliant Yellow dye on tared weighing paper. Pour the dust into a 0.6 mL microcentrifuge tube and tightly close the cap. 
	NOTE: We advise the use of nitrile gloves during aliquot preparation, as some latex gloves are permeable to the dye.</li>
	<li>Repeat step 1.2) for all samples in the experiment (one for every fly in each chamber).</li>
	<li>Prepare ethanol (EtOH) tubes: Pipet&#160;1 mL of 100% EtOH into 1.5 mL microcentrifuge tubes. Label tubes for genotypes or conditions.</li>
	<li>Repeat step 1.4) for all samples in the experiment (one for every fly in each chamber). Cap and save the EtOH tubes for completion of the grooming assay. Also include at least one &#34;Blank&#34; sample which will only be 1 mL EtOH without a fly for negative controls.</li>
	<li>Assemble each grooming chamber by screwing the sliding top plate (with the smaller holes) but leaving the bottom plate (with the larger holes) removed for addition of dust.</li>
	<li>Place each necessary grooming chamber flat on a table with the top face down. Fly entry side is face-down.</li>
	<li>Load 5 mg Brilliant Yellow dye aliquot into each chamber by tapping the tube against the surface of the chamber above the desired well. Tap the chamber against the table to ensure that all of the dust falls through the mesh to the top plate.</li>
	<li>Screw the bottom plate onto each chamber such that the wider ends of the conical openings face outward and the holes do not rest over the wells. Secure the bottom plate tightly so that it does not slide and release dye.</li>
	<li>Flip the chamber over and knock it flat against a table a few times so that the dust falls through the mesh to rest on the bottom plate.</li>
	<li>Slide the top plate of the chamber into the &#34;open position&#34; so that the small holes align with the fifteen wells, allowing the introduction of flies into individual wells.</li>
</ol>
2. Fly-dusting and Grooming
<ol>
	<li>Load one fly into the mouth aspirator by gently sucking through one end of the aspirator as if using a straw. Deposit the flies by lightly blowing and directing the opening toward the target.</li>
	<li>Aspirate one fly into each well used for the experiment. After loading a well, slide the top plate so that the fly is trapped in the chamber and place tape over the opening of that well during loading of the whole chamber to prevent the fly&#39;s escape while loading other wells. If multiple flies are aspirated into a single well, leave that opening uncovered until only one fly remains.</li>
	<li>After all of the necessary wells are filled with flies, flip the chamber such that the bottom plate is upward so that the dust has the potential to coat the flies by falling through the mesh.</li>
	<li>Tightly secure the top and bottom plates by tightening the screws, and vortex the chamber to dust the flies for 4 s.</li>
	<li>Knock the chamber (top plate facedown) against a table twice so that dye falls through to the other side. Then, flip the chamber over (top plate face-up) and knock the chamber twice to ensure dye settles on the floor of the bottom chamber away from the fly held in the top chamber.</li>
	<li>For control flies which are not allowed to groom, immediately proceed to Step 3 of the protocol. For flies that will complete the assay, proceed to Step 2.7.</li>
	<li>Rest the chamber flat on a table or countertop with the top plate upward for thirty minutes to allow the flies to groom. Place the chamber in a noise and vibration-free space to keep your environment constant for all grooming experiments (lighting levels, humidity, and temperature). A tabletop incubator at RT or 25 &#176;C with humidity controls is ideal.</li>
</ol>
3. Preparation of Samples and Absorbance Analysis
<ol>
	<li>Keeping the chamber level with the top plate upward, gently unscrew the bottom plate and remove it from the chamber, taking care not to lose dye.</li>
	<li>Place the chamber on a Fly CO2 pad with low airflow until the flies are anaesthetized.</li>
	<li>Unscrew the top plate from the chamber. Carefully use forceps to grab a leg and move one dusted fly from each chamber and deposit it in a 1.5 mL microcentrifuge tube containing EtOH. The transfer time for 15 chambers each containing one fly is approximately 3-5&#160;min. Experimenters should factor in transfer times if/when staggering experiments with multiple chambers to ensure efficient staging of experiments.</li>
	<li>Once each microcentrifuge tube contains 1 fly, close the cap and invert the tube three times to agitate and mix the solution of dye and ethanol.</li>
	<li>Incubate tubes containing ethanol and flies for 5 h at RT to ensure full removal of the dye from the fly into solution. After the 5 h, briefly vortex each tube (2 s) to ensure clearance of the dye from the flies.</li>
	<li>Aliquot 50 &#181;L of the experimental 1.5 mL tube into a well of a 96-well plate if available, taking note of the location of each sample on the plate. Add 200 &#181;L of EtOH to dilute the sample 5x. The dilution avoids ceiling effects of heavily dusted flies or large grooming defects.</li>
	<li>Use a plate reader to analyze each sample at 397 nm. Alternatively, measure absorbance for individual samples and blanks on a standard spectrophotometer in the visible spectrum if a plate reader is unavailable.</li>
	<li>Read and record the sample through the plate reader and save the spreadsheet with the recorded samples on the plate.</li>
</ol>
4. Quantification of Results
<ol>
	<li>Compile results for all samples and measure the variance for each genotype or condition. 
	NOTE: Dye accumulation at time 0 min and at time 30 min are regarded as separate conditions using statistical analysis by one-way ANOVA and Bonferroni correction or other corrections for multiple parallel comparisons.</li>
	<li>Calculate grooming percentage difference for each genotype/condition using the following equation: [(dye accumulation mean value at time 0&#39; - dye accumulation mean value at time 30&#39;) / dye accumulation mean value at time 0] x 100.</li>
	<li>Express the percentage for each genotype and condition in bar plots and compare across genotypes and conditions.</li>
</ol>

<ol>
	<li>Szebenyi, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleaning+Behaviour+in+Drosophila-Melanogaster.">Cleaning Behaviour in Drosophila-Melanogaster.</a> Animal. Behaviour. 17, (1969).</li><li>Corfas, G., Dudai, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Habituation+and+dishabituation+of+a+cleaning+reflex+in+normal+and+mutant+Drosophila.">Habituation and dishabituation of a cleaning reflex in normal and mutant Drosophila.</a> J Neurosci. 9 (1), 56-62 (1989).</li><li>Yanagawa, A., Guigue, A. M. A., Marion-Poll, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hygienic+grooming+is+induced+by+contact+chemicals+in+Drosophila+melanogaster.">Hygienic grooming is induced by contact chemicals in Drosophila melanogaster.</a> Frontiers in Behavioral Neuroscience. 8, (2014).</li><li>Dawkins, R., Dawkins, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hierarchical+Organization+and+Postural+Facilitation+-+Rules+for+Grooming+in+Flies.">Hierarchical Organization and Postural Facilitation - Rules for Grooming in Flies.</a> Animal Behaviour. 24 (Nov), 739-755 (1976).</li><li>Seeds, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+suppression+hierarchy+among+competing+motor+programs+drives+sequential+grooming+in+Drosophila.">A suppression hierarchy among competing motor programs drives sequential grooming in Drosophila.</a> Elife. 3, e02951 (2014).</li><li>King, L. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurofibromin+Loss+of+Function+Drives+Excessive+Grooming+in+Drosophila.">Neurofibromin Loss of Function Drives Excessive Grooming in Drosophila.</a> G3-Genes Genomes Genetics. 6 (4), 1083-1093 (2016).</li><li>Tauber, J. M., Vanlandingham, P. A., Zhang, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elevated+Levels+of+the+Vesicular+Monoamine+Transporter+and+a+Novel+Repetitive+Behavior+in+the+Drosophila+Model+of+Fragile+X+Syndrome.">Elevated Levels of the Vesicular Monoamine Transporter and a Novel Repetitive Behavior in the Drosophila Model of Fragile X Syndrome.</a> Plos One. 6 (11), e27100 (2011).</li><li>Kaur, K., Simon, A. F., Chauhan, V., Chauhan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+bisphenol+A+on+Drosophila+melanogaster+behavior--a+new+model+for+the+studies+on+neurodevelopmental+disorders.">Effect of bisphenol A on Drosophila melanogaster behavior--a new model for the studies on neurodevelopmental disorders.</a> Behav Brain Res. 284, 77-84 (2015).</li><li>Chang, H. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overexpression+of+the+Drosophila+vesicular+monoamine+transporter+increases+motor+activity+and+courtship+but+decreases+the+behavioral+response+to+cocaine.">Overexpression of the Drosophila vesicular monoamine transporter increases motor activity and courtship but decreases the behavioral response to cocaine.</a> Molecular Psychiatry. 11 (1), 99-113 (2006).</li><li>Yellman, C., Tao, H., He, B., Hirsh, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conserved+and+sexually+dimorphic+behavioral+responses+to+biogenic+amines+in+decapitated+Drosophila.">Conserved and sexually dimorphic behavioral responses to biogenic amines in decapitated Drosophila.</a> Proceedings of the National Academy of Sciences of the United States of America. 94 (8), 4131-4136 (1997).</li><li>Feng, G. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cloning+and+functional+characterization+of+a+novel+dopamine+receptor+from+Drosophila+melanogaster.">Cloning and functional characterization of a novel dopamine receptor from Drosophila melanogaster.</a> Journal of Neuroscience. 16 (12), 3925-3933 (1996).</li><li>Gotzes, F., Balfanz, S., Baumann, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+Structure+and+Functional-Characterization+of+a+Drosophila+Dopamine-Receptor+with+High+Homology+to+Human+D(1/5).">Primary Structure and Functional-Characterization of a Drosophila Dopamine-Receptor with High Homology to Human D(1/5).</a> Receptors. Receptors &amp; Channels. 2 (2), 131-141 (1994).</li><li>Han, K. A., Millar, N. S., Grotewiel, M. S., Davis, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DAMB,+a+novel+dopamine+receptor+expressed+specifically+in+Drosophila+mushroom+bodies.">DAMB, a novel dopamine receptor expressed specifically in Drosophila mushroom bodies.</a> Neuron. 16 (6), 1127-1135 (1996).</li><li>Sugamori, K. S., Demchyshyn, L. L., Mcconkey, F., Forte, M. A., Niznik, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Primordial+Dopamine+D1-Like+Adenylyl+Cyclase-Linked+Receptor+from+Drosophila-Melanogaster+Displaying+Poor+Affinity+for+Benzazepines.">A Primordial Dopamine D1-Like Adenylyl Cyclase-Linked Receptor from Drosophila-Melanogaster Displaying Poor Affinity for Benzazepines.</a> Febs Letters. 362 (2), 131-138 (1995).</li><li>Pitmon, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+D1+family+dopamine+receptor,+DopR,+potentiates+hind+leg+grooming+behavior+in+Drosophila.">The D1 family dopamine receptor, DopR, potentiates hind leg grooming behavior in Drosophila.</a> Genes Brain and Behavior. 15 (3), 327-334 (2016).</li><li>Phillis, R. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+mutations+affecting+neural+circuitry+required+for+grooming+behavior+in+Drosophila+melanogaster.">Isolation of mutations affecting neural circuitry required for grooming behavior in Drosophila melanogaster.</a> Genetics. 133 (3), 581-592 (1993).</li><li>Hampel, S., Franconville, R., Simpson, J. H., Seeds, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+neural+command+circuit+for+grooming+movement+control.">A neural command circuit for grooming movement control.</a> Elife. 4, e08758 (2015).</li><li>Kays, I., Cvetkovska, V., Chen, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+and+functional+analysis+of+single+neurons+to+correlate+synaptic+connectivity+with+grooming+behavior.">Structural and functional analysis of single neurons to correlate synaptic connectivity with grooming behavior.</a> Nature Protocols. 9 (1), 1-10 (2014).</li></ol>

The authors declare no conflicts of interest.

The grooming assay is relatively straightforward, but we would caution experimenters to pay special attention to the following issues. Maintaining a tight seal by tightening the screws on the top and bottom plates after introducing flies and dye is essential for reproducible results. The Brilliant Yellow dye is very fine and loose joints will allow losses of dye from the edges of the chamber. The irregularity in dye content for each well could easily throw off grooming quantification as non-uniform dusting will increase ...

Grooming in Drosophila melanogaster&#160;(D. melanogaster&#160;)&#160;is a robust innate behavior that involves the coordination of multiple independent motor programs1. Fruit flies clean their bodies of dust, microbes, and other pathogens which could inhibit normal physiological function such as vision and flight, or lead to significant immune challenges. In sensing and responding to both mechanical2 and immune activation3, flies repetitively rub their legs together or on a targeted body region until it is sufficiently clean and grooming progresses to another part of the body. Flies perform grooming movements in distinct bouts that largely occur in stereotyped patterns1,4. A behavioral hierarchy becomes apparent as grooming signals are prioritized. Circuits and patterns of activity have been identified in support of a model that grooming programs at the top of the hierarchy occur first and suppress parallel signals from areas of the body that are groomed subsequently5. Highest priority is given to the head, then the abdomen, wings, and finally the thorax5.
The grooming program in D. melanogaster is an ideal system for studying neural circuits, modulatory molecular signals, and neurotransmitters. For instance, compromise of neurofibromin function6, loss of Drosophila fragile X mental retardation protein (dfmr1)7, and exposure to bisphenol A (BPA)8 all cause excessive grooming and other behaviors that are analogous to discrete human symptoms of neurofibromatosis, fragile X syndrome, and aspects of autism spectrum disorders and Attention-deficit Hyperactivity Disorder (ADHD), respectively. Grooming behavior can also be habituated differentially across mutant strains2, lending this motor program to studies of behavioral plasticity. The breadth of neurological phenomena that can be modeled by Drosophila demands a novel comparative approach to measure the ability of flies to groom themselves.
The combined action of vesicular monoamine transporters and the relative abundance of dopamine and other biogenic amines in the body have been shown to mediate fruit fly grooming behavior 9,10. Octopamine and dopamine stimulate comparable hindleg grooming activity in decapitated flies, while tyramine, the precursor of octopamine, also triggers grooming to a lesser extent7. Four dopamine receptors have been identified in D. melanogaster11,12,13,14. By using the grooming assay method described in this protocol, we determined a role for the Type I family Dopamine Receptor DopR (DopR, dDA1, dumb) in hindleg grooming behavior15.
Grooming can be indirectly quantified by looking at the extent of cleanliness by which an animal can fully groom after dusting the entire body with a marker dye or fluorescent dust5,16. The remainder of dust left on the body can be used as a relative marker for the overall behavior. Dusty flies after being given sufficient time to groom may be manifesting a specific deficit in grooming behavior. As grooming investigations have become more extensive, protocols have incorporated such practices as decapitation to add pharmacological treatments onto the neck connective nerves10, tactile stimulation of bristles to elicit the grooming response2 , and video recording of behavior15. Direct observation of grooming can be easily studied by using visual observation and manually recording the frequency and duration of specific grooming events4.
We designed a fifteen-well grooming chamber that can be constructed with a 3D printer or laser cutter, and the blueprint designs are available for reproduction15. The design uses two joined central plates with openings matched and separated by mesh and two additional sliding top and bottom plates, from which flies and/or dye is loaded, respectively. After allowing dusted flies time to groom, we deposit them in ethanol to solubilize the dye and measure the absorbance of this solution at the wavelength of the dye. A plate reader can be used for multiple parallel samples or a single-read spectrophotometer can be used for individual samples. This method minimizes the error induced by handling and allows for grooming assays to be run on a smaller, cost-efficient scale. This method is derived and modified from the methods pioneered by Julie Simpson and Andrew Seeds, who use larger grooming chambers with heating elements for temperature sensitive circuit manipulations5. The following protocol showcases the quantification of grooming of the whole body as well as showing alternate methods for quantitation of dye accumulation on individual body parts. We also present sample comparison data between WT and DopR mutants, as well as methods for calculating a simple performance index for grooming behavior.

<table><tbody><tr><td>High-Flex Tygon PVC Clear Tubing</td><td>McMaster-Carr</td><td>5229K54</td><td>ID 1/8&quot;, OD 1/4&quot;, used with micropipettor tips and mesh to construct mouth aspirators</td></tr><tr><td>Micropipette tips (1 mL and 200 &amp;#956;L)</td><td>Genesee Scientific</td><td>24-165, 24-150R</td><td></td></tr><tr><td>Nylon Mesh Screen, 2 x 2.6&quot;</td><td>McMaster-Carr</td><td>9318T44</td><td>Used to construct grooming chamber and mouth aspirators</td></tr><tr><td>Dumont #5 Forceps</td><td>Roboz Surgical Instrument</td><td>RS-5050</td><td></td></tr><tr><td>Brilliant Yellow Dye</td><td>Sigma-Aldrich</td><td>201375-25G</td><td>we recommend use of nitrile gloves while handling this product</td></tr><tr><td>Vortexer</td><td>Fisher Scientific</td><td>12-812</td><td>set to &quot;touch&quot;</td></tr><tr><td>Ethanol</td><td>Carolina Biological Supply</td><td>86-1282</td><td></td></tr><tr><td>1.5 mL microcentrifuge tubes</td><td>VWR International</td><td>10025-726</td><td></td></tr><tr><td>0.65 mL microcentrifuge tubes</td><td>VWR International</td><td>20170-293</td><td>tubes can be reused with successive assays</td></tr><tr><td>UV 96-well plate</td><td>Corning</td><td>26014017</td><td></td></tr><tr><td>BioTek Synergy HTX Platereader</td><td>BioTek</td><td>need to download catalog to access product number</td><td>http://www.biotek.com/products/microplate_detection/synergy_htx_multimode_microplate_reader.html?tab=overview</td></tr><tr><td>Gen5 Microplate Reader and Imager Software</td><td>BioTek</td><td></td><td></td></tr><tr><td>Microsoft Excel</td><td>Microsoft</td><td></td><td>https://www.microsoftstore.com/store/msusa/en_US/pdp/Excel-2016/productID.323021400?tduid=(65d098c0e83b86c952bdff5b0719c83f)(256380)(2459594)(SRi0yYDlqd0-LI..ql4M2LoZBEhcBljvIA)()</td></tr><tr><td>Drosophila Incubator</td><td>Tritech</td><td>DT2-CIRC-TK</td><td></td></tr><tr><td>1/4&quot; acrylic plastic</td><td>McMaster-Carr</td><td>8473K341</td><td></td></tr><tr><td>8 - 32 nuts</td><td>McMaster-Carr</td><td>90257A009</td><td></td></tr><tr><td>8 - 32 x 1&quot; hex cap screws</td><td>McMaster-Carr</td><td>92185A199</td><td>the bottom plate needs to be tapped for this size screw</td></tr><tr><td>8 - 32 x 1/2&quot; hex cap screws</td><td>McMaster-Carr</td><td>92185A194</td><td>the second plate from the top needs to be tapped</td></tr><tr><td>2 - 56 3/8&quot; flat head phillips machine screws</td><td>McMaster-Carr</td><td>91500A088</td><td>these hold the two middle plates together</td></tr><tr><td>0.175&quot; ID, 1/4&quot; OD, 0.34&quot; aluminum pipe</td><td>McMaster-Carr</td><td>92510A044</td><td>Manufactured in-house; product listed is approximately the same dimensions and should work for size 8 screws.&amp;nbsp; These act as sheaths for the 1&quot; screws and set the hex cap up slightly from the surface of the top plate</td></tr></tbody></table>

quantification of drosophila grooming behavior

Drosophila grooming behavior is a complex multi-step locomotor program that requires coordinated movement of both forelegs and hindlegs. Here we present a grooming assay protocol and novel chamber design that is cost-efficient and scalable for either small or large-scale studies of Drosophila grooming. Flies are dusted all over their body with Brilliant Yellow dye and given time to remove the dye from their bodies within the chamber. Flies are then deposited in a set volume of ethanol to solubilize the dye. The relative spectral absorbance of dye-ethanol samples for groomed versus ungroomed animals are measured and recorded. The protocol yields quantitative data of dye accumulation for individual flies, which can be easily averaged and compared across samples. This allows experimental designs to easily evaluate grooming ability for mutant animal studies or circuit manipulations. This efficient procedure is both versatile and scalable. We show work-flow of the protocol and comparative data between WT animals and mutant animals for the Drosophila type I Dopamine Receptor (DopR).

The grooming assay yields quantitative data to assess behavioral performance based on the relative remainder of accumulated dye left on the bodies of flies after a set time of measurement for grooming (30 min). Sample images of the sliding grooming chamber design and major steps of the assay are highlighted in Figure 1. Flies aggregate a significant amount of dye from immediate dusting by vortexing in the presence of dye (Figure 2d, 2e). Dusted flies can ...

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Quantification of Drosophila Grooming Behavior

This protocol describes a scalable individual grooming assay technique in Drosophila that yields robust, quantitative data to measure grooming behavior. The method is based on comparing the difference in dye accumulation on the bodies of un-groomed versus groomed animals over a set period of time.

Drosophila grooming behavior is a complex multi-step locomotor program that requires coordinated movement of both forelegs and hindlegs. Here we present a ...

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9.0K Views.  Williams College. This protocol describes a scalable individual grooming assay technique in Drosophila that yields robust, quantitative data to measure grooming behavior. The method is based on comparing the difference in dye accumulation on the bodies of un-groomed versus groomed animals over a set period of time.

Video: Quantification of Drosophila Grooming Behavior

Methods to Assay Drosophila Behavior

Drosophila melanogaster, the fruit fly, has been used to study molecular mechanisms of a wide range of human diseases such as cancer, cardiovascular disease and various neurological diseases1. We have optimized simple and robust behavioral assays for determining larval locomotion, adult climbing ability (RING assay), and courtship behaviors of Drosophila. These behavioral assays are widely applicable for studying the role of genetic and environmental factors on fly behavior. Larval crawling ability can be reliably used for determining early stage changes in the crawling abilities of Drosophila larvae and also for examining effect of drugs or human disease genes (in transgenic flies) on their locomotion. The larval crawling assay becomes more applicable if expression or abolition of a gene causes lethality in pupal or adult stages, as these flies do not survive to adulthood where they otherwise could be assessed. This basic assay can also be used in conjunction with bright light or stress to examine additional behavioral responses in Drosophila larvae. Courtship behavior has been widely used to investigate genetic basis of sexual behavior, and can also be used to examine activity and coordination, as well as learning and memory. Drosophila courtship behavior involves the exchange of various sensory stimuli including visual, auditory, and chemosensory signals between males and females that lead to a complex series of well characterized motor behaviors culminating in successful copulation. Traditional adult climbing assays (negative geotaxis) are tedious, labor intensive, and time consuming, with significant variation between different trials2-4. The rapid iterative negative geotaxis (RING) assay5 has many advantages over more widely employed protocols, providing a reproducible, sensitive, and high throughput approach to quantify adult locomotor and negative geotaxis behaviors. In the RING assay, several genotypes or drug treatments can be tested simultaneously using large number of animals, with the high-throughput approach making it more amenable for screening experiments.

Methods to Assay Drosophila Behavior

Drosophila melanogaster is a genetically and behaviorally tractable model system that has been used to understand the molecular and cellular basis of many important biological processes for over a century 1. Drosophila has been well exploited to gain insights into the genetic basis of fly behavior.

Drosophila melanogaster, the fruit fly, has been used to study molecular mechanisms of a wide range of human diseases such as cancer, cardiovascular ...

Drosophila Passive Avoidance Behavior as a New Paradigm to Study Associative Aversive Learning

This protocol describes a new paradigm for analyzing aversive associative learning in adult flies (Drosophila melanogaster). The paradigm is analogous to passive avoidance behavior in laboratory rodents in which animals learn to avoid a compartment where they have previously received an electric shock. The assay takes advantage of negative geotaxis in flies, which manifests as an urge to climb up when they are placed on a vertical surface. The setup consists of vertically oriented upper and lower compartments. On the first trial, a fly is placed into a lower compartment from where it usually exits&#160;within 3-15 s, and steps into the upper compartment where it receives an electric shock. During the second trial, 24 h later, the latency is significantly increased. At the same time, the number of shocks is decreased compared to the first trial, indicating that flies formed long-term memory about the upper compartment. The recordings of latencies and number of shocks could be performed with a tally counter and a stopwatch or with an Arduino-based simple device. To illustrate how the assay can be used, the passive avoidance behavior of D. melanogaster and D. simulans male and female were characterized here. Comparison of latencies and number of shocks revealed that both D. melanogaster and D. simulans flies efficiently learned the passive avoidance behavior. No statistical differences were observed between male and female flies. However, males were a little faster while entering the upper compartment on the first trial, while females received a slightly higher number of shocks in every retention trial. The Western diet (WD) significantly impaired learning and memory in male flies while flight exercise counterbalanced this effect. Taken together, the passive avoidance behavior in flies offers a simple and reproducible assay that could be used for studying basic mechanisms of learning and memory.

Drosophila Passive Avoidance Behavior as a New Paradigm to Study Associative Aversive Learning

This work describes a simple behavioral paradigm that allows the analysis of aversive associative learning in adult fruit flies. The method is based on suppressing the innate negative geotaxis behavior due to the association formed between a specific environmental context and an electric shock.

This protocol describes a new paradigm for analyzing aversive associative learning in adult flies (Drosophila melanogaster). The paradigm is analogous to ...

Behavior

Acquisition of High-Quality Digital Video of Drosophila Larval and Adult Behaviors from a Lateral Perspective

Drosophila melanogaster is a powerful experimental model system for studying the function of the nervous system. Gene mutations that cause dysfunction of the nervous system often produce viable larvae and adults that have locomotion defective phenotypes that are difficult to adequately describe with text or completely represent with a single photographic image. Current modes of scientific publishing, however, support the submission of digital video media as supplemental material to accompany a manuscript. Here we describe a simple and widely accessible microscopy technique for acquiring high-quality digital video of both Drosophila larval and adult phenotypes from a lateral perspective. Video of larval and adult locomotion from a side-view is advantageous because it allows the observation and analysis of subtle distinctions and variations in aberrant locomotive behaviors. We have successfully used the technique to visualize and quantify aberrant crawling behaviors in third instar larvae, in addition to adult mutant phenotypes and behaviors including grooming.

Acquisition of High-Quality Digital Video of Drosophila Larval and Adult Behaviors from a Lateral Perspective

Here we describe a simple and widely accessible microscopy technique to acquire high-quality digital video of Drosophila adult and larval mutant phenotypes from a lateral perspective.

Drosophila melanogaster is a powerful experimental model system for studying the function of the nervous system. Gene mutations that cause dysfunction of ...

Behavioral Assays for Autism Spectrum Disorder in Mouse Models

Strategies for Assessing Autistic-Like Behaviors in Mice

Autism spectrum disorder (ASD) is a neurobiologically complex condition with a heterogeneous genetic etiology. Clinically, ASD is diagnosed by social communication impairments and restrictive or repetitive behaviors, such as hand flapping or lining up objects. These behavioral patterns can be reliably observed in mouse models with ASD-linked genetic mutations, making them highly useful tools for studying the underlying cellular and molecular mechanisms in ASD. Understanding how genetic changes affect the neurobiology and behaviors observed in ASD will facilitate the development of novel targeted therapeutic compounds to ameliorate core behavioral impairments. Our lab has employed several protocols encompassing well-described training and testing procedures that reflect a wide range of behavioral deficits related to ASD. Here, we detail two assays to study the core features of ASD in mouse models: self-grooming (a measure of repetitive behavior) and the three-chamber social interaction test (a measure of social interaction approach and preference for social novelty).

Rodent models are valuable tools for studying core behaviors related to autism spectrum disorder (ASD). In this article, we expound on two behavioral tests for modeling the core features of ASD in mice: self-grooming, which assesses repetitive behavior, and the three-chamber social interaction test, which documents social impairments.

Autism spectrum disorder (ASD) is a neurobiologically complex condition with a heterogeneous genetic etiology. Clinically, ASD is diagnosed by social ...

High-resolution Quantification of Odor-guided Behavior in Drosophila melanogaster Using the Flywalk Paradigm

In their natural environment, insects such as the vinegar fly Drosophila melanogaster are bombarded with a huge amount of chemically distinct odorants. To complicate matters even further, the odors detected by the insect nervous system usually are not single compounds but mixtures whose composition and concentration ratios vary. This leads to an almost infinite amount of different olfactory stimuli which have to be evaluated by the nervous system.
To understand which aspects of an odor stimulus determine its evaluation by the fly, it is therefore desirable to efficiently examine odor-guided behavior towards many odorants and odor mixtures. To directly correlate behavior to neuronal activity, behavior should be quantified in a comparable time frame and under identical stimulus conditions as in neurophysiological experiments. However, many currently used olfactory bioassays in Drosophila neuroethology are rather specialized either towards efficiency or towards resolution.
Flywalk, an automated odor delivery and tracking system, bridges the gap between efficiency and resolution. It allows the determination of exactly when an odor packet stimulated a freely walking fly, and to determine the animal&#180;s dynamic behavioral reaction.

High-resolution Quantification of Odor-guided Behavior in Drosophila melanogaster Using the Flywalk Paradigm

The automated tracking system Flywalk is used for high-resolution quantification of odor-guided behavior in Drosophila melanogaster.

In their natural environment, insects such as the vinegar fly Drosophila melanogaster are bombarded with a huge amount of chemically distinct odorants. To ...

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense organs provide an excellent model system for the study of mechanosensation. This protocol describes a simple touch behavior in fruit flies which can be used to identify mutations that interfere with mechanosensation. The tactile stimulation of a macrochaete bristle on the thorax of flies elicits a grooming reflex from either the first or third leg. Mutations that interfere with mechanotransduction (such as NOMPC), or with other aspects of the reflex arc, can inhibit the grooming response. A traditional screen of adult behaviors would have missed mutants that have essential roles during development. Instead, this protocol combines the touch screen with mosaic analysis with a repressible cell marker (MARCM) to allow for only limited regions of homozygous mutant cells to be generated and marked by the expression of green fluorescent protein (GFP). By testing MARCM clones for abnormal behavioral responses, it is possible to screen a collection of lethal p-element mutations to search for new genes involved in mechanosensation that would have been missed by more traditional methods.

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

In order to identify novel mutations affecting mechanosensation, we designed an assay that measures the behavioral response to tactile stimulation of fly bristles in mutant clones generated by the MARCM method. The combination of techniques allows for the identification of mechanosensitive mutations that would otherwise be lethal.

Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense ...

Drosophila Courtship Conditioning As a Measure of Learning and Memory

Many insights into the molecular mechanisms underlying learning and memory have been elucidated through the use of simple behavioral assays in model organisms such as the fruit fly, Drosophila melanogaster. Drosophila is useful for understanding the basic neurobiology underlying cognitive deficits resulting from mutations in genes associated with human cognitive disorders, such as intellectual disability (ID) and autism. This work describes a methodology for testing learning and memory using a classic paradigm in Drosophila known as courtship conditioning. Male flies court females using a distinct pattern of easily recognizable behaviors. Premated females are not receptive to mating and will reject the male&#39;s copulation attempts. In response to this rejection, male flies reduce their courtship behavior. This learned reduction in courtship behavior is measured over time, serving as an indicator of learning and memory. The basic numerical output of this assay is the courtship index (CI), which is defined as the percentage of time that a male spends courting during a 10 min interval. The learning index (LI) is the relative reduction of CI in flies that have been exposed to a premated female compared to na&#239;ve flies with no previous social encounters. For the statistical comparison of LIs between genotypes, a randomization test with bootstrapping is used. To illustrate how the assay can be used to address the role of a gene relating to learning and memory, the pan-neuronal knockdown of Dihydroxyacetone phosphate acyltransferase (Dhap-at) was characterized here. The human ortholog of Dhap-at, glyceronephosphate O-acyltransferase (GNPT), is involved in rhizomelic chondrodysplasia punctata type 2, an autosomal-recessive syndrome characterized by severe ID. Using the courtship conditioning assay, it was determined that Dhap-at is required for long-term memory, but not for short-term memory. This result serves as a basis for further investigation of the underlying molecular mechanisms.

Drosophila Courtship Conditioning As a Measure of Learning and Memory

This protocol describes a Drosophila learning and memory assay called courtship conditioning. This classic assay is based on a reduction of male courtship behavior after sexual rejection by a non-receptive premated female. This natural form of behavioral plasticity can be used to test learning, short-term memory, and long-term memory.

Many insights into the molecular mechanisms underlying learning and memory have been elucidated through the use of simple behavioral assays in model ...

Drosophila Models for Genetic and Behavioral Traits of Autism Spectrum Disorder

Paradigms for Behavioral Assessment in Drosophila Model of Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) encompasses a heterogeneous group of neurodevelopmental disorders with common behavioral symptoms including deficits in social interaction and ability for communication, enhanced restricted or repetitive behaviors, and also, in some cases, learning disability and motor deficit. Drosophila has served as an unparalleled model organism for modeling a great number of human diseases. As many genes have been implicated in ASD, fruit flies have emerged as a powerful and efficient way to test the genes putatively involved with the disorder. As hundreds of genes, with varied functional roles, are implicated in ASD, a single genetic fly model of ASD is unfeasible; instead, individual genetic mutants, gene knockdowns, or overexpression-based studies of the fly homologs of ASD-associated genes are the common means for gaining insight regarding molecular pathways underlying these gene products. A host of behavioral techniques are available in Drosophila which provide easy readout of deficits in specific behavioral components. Social space assay and aggression and courtship assays in flies have been shown to be useful in assessing defects in social interaction or communication. Grooming behavior in flies is an excellent readout of repetitive behavior. Habituation assay is used in flies to estimate the ability for habituation learning, which is found to be affected in some ASD patients. A combination of these behavioral paradigms can be utilized to make a thorough assessment of the human ASD-like disease state in flies. Using Fmr1 mutant flies, recapitulating Fragile-X syndrome in humans, and POGZ-homolog row knockdown in fly neurons, we have shown quantifiable deficits in social spacing, aggression, courtship behavior, grooming behavior, and habituation. These behavioral paradigms are demonstrated here in their simplest and straightforward forms with an assumption that it would facilitate their widespread use for research on ASD and other neurodevelopmental disorders in fly models.

Author Spotlight: Exploring Autism Spectrum Disorder Symptoms in Fruit Flies &#8212; Genetic Models and Behavioral Tests

Autism Spectrum Disorder (ASD) is associated with impaired social and communicative behavior and the emergence of repetitive behavior. For studying the interrelation between ASD genes and behavioral deficits in the Drosophila model, five behavioral paradigms are described in this paper for assaying social spacing, aggression, courtship, grooming, and habituation behavior.

Autism Spectrum Disorder (ASD) encompasses a heterogeneous group of neurodevelopmental disorders with common behavioral symptoms including deficits in ...

Quantification of Drosophila melanogaster Grooming Behavior for Evaluation of Excessive Grooming Phenotypes

Observable changes in stereotyped grooming are applied translationally in model organisms. These changes are representative of pathologies that elicit similar deviations in human behavior; for example, excessive grooming acts as a proxy for obsessive and compulsive behaviors present in conditions like Tourette Syndrome or obsessive-compulsive disorder. The grooming assay presented allows for the evaluation of abnormal self-grooming phenotypes in Drosophila melanogaster. Flies are recorded for a period of 10 min, and these recordings are observed and annotated blind for previously defined grooming behaviors. Quantitative measures of both grooming bout frequency and the time spent engaging in self-grooming can be obtained by manually annotating the footage. The assay is relatively inexpensive, requires few materials not already available in laboratory environments, and is easily adaptable to fit the specific needs of any given study aiming to observe grooming. Additionally, the low level of skill needed to perform the assay, as compared to computer science-heavy automated methods, makes the protocol well-suited for small labs and students. We discuss in detail the steps required to perform this assay and its present limitations.

The method presented here involves the manual annotation of footage acquired of Drosophila melanogaster for specific grooming behaviors. It allows for quantification of both the number of grooming bouts and overall time spent grooming to evaluate for atypical self-grooming phenotypes.

Observable changes in stereotyped grooming are applied translationally in model organisms. These changes are representative of pathologies that elicit ...

High-Resolution Imaging and Analysis of Drosophila Eye Defects

A Rapid, Simple Workflow for Quantification of External Adult Drosophila Structures

The Drosophila compound eye is a precisely patterned tissue that has revealed molecular mechanisms and biological processes that drive morphogenesis. It is a simple structure of repeating unit eyes, termed ommatidia, that is used to characterize genetic interactions and gene functions. Mutations that affect eye architecture can be easily detected and analyzed; hence, this system is frequently used in under-resourced institutions. Further phenotypic analysis often includes a Scanning Electron Microscope (SEM) to generate high-magnification images suitable for quantitative analysis. However, SEMs are expensive and require costly reagents; sample preparation spans days; and, often, they need full-time staff for sample preparation and instrument maintenance. This limits their utility at under-resourced institutions or during budgetary austerity. In entomology, the use of high-resolution digital imaging technology is a common practice for the identification and characterization of species. This paper describes a method that combines strategies and allows for high-resolution digital imaging of adult Drosophila structures and quantitative analysis using the open software ImageJ. The workflow is a rapid and student-friendly alternative that remedies the limitations of underfunded and under-resourced research facilities with a cost-effective and rapid approach to quantitative phenotypic analysis.

Here, we present a rapid, low-cost, workflow for high-resolution imaging of adult Drosophila eyes to quantify patterning and growth defects. We describe our protocol for sample preparation by point-mounting, high-resolution image acquisition, and image analysis.

The Drosophila compound eye is a precisely patterned tissue that has revealed molecular mechanisms and biological processes that drive morphogenesis. It ...

Quantification of Drosophila Grooming Behavior

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Chapters in this video

Methods to Assay Drosophila Behavior

Drosophila Passive Avoidance Behavior as a New Paradigm to Study Associative Aversive Learning

Acquisition of High-Quality Digital Video of Drosophila Larval and Adult Behaviors from a Lateral Perspective

Strategies for Assessing Autistic-Like Behaviors in Mice

High-resolution Quantification of Odor-guided Behavior in Drosophila melanogaster Using the Flywalk Paradigm

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

Drosophila Courtship Conditioning As a Measure of Learning and Memory

Paradigms for Behavioral Assessment in Drosophila Model of Autism Spectrum Disorder

Quantification of Drosophila melanogaster Grooming Behavior for Evaluation of Excessive Grooming Phenotypes

A Rapid, Simple Workflow for Quantification of External Adult Drosophila Structures