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>
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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 border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>High-Flex Tygon PVC Clear Tubing</td>
			<td>McMaster-Carr</td>
			<td>5229K54</td>
			<td>ID 1/8&#34;, OD 1/4&#34;, used with micropipettor tips and mesh to construct mouth aspirators</td>
		</tr>
		<tr>
			<td>Micropipette tips (1ml and 200ul)</td>
			<td>Genesee Scientific</td>
			<td>24-165, 24-150R</td>
			<td></td>
		</tr>
		<tr>
			<td>Nylon Mesh Screen, 2&#34; x 2.6&#34;</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 &#34;touch&#34;</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&#34; 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&#34; 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&#34; 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&#34; 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&#34; ID, 1/4&#34; OD, 0.34&#34; 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.&#160; These act as sheaths for the 1&#34; 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 ...

quantification-of-drosophila-grooming-behavior

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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

Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae

The sense of smell is essential for insects to find foods, mates, predators, and oviposition sites3. Insect olfactory sensory neurons (OSNs) are enclosed in sensory hairs called sensilla, which cover the surface of olfactory organs. The surface of each sensillum is covered with tiny pores, through which odorants pass and dissolve in a fluid called sensillum lymph, which bathes the sensory dendrites of the OSNs housed in a given sensillum. The OSN dendrites express odorant receptor (OR) proteins, which in insects function as odor-gated ion channels4, 5. The interaction of odorants with ORs either increases or decreases the basal firing rate of the OSN. This neuronal activity in the form of action potentials embodies the first representation of the quality, intensity, and temporal characteristics of the odorant6, 7.
Given the easy access to these sensory hairs, it is possible to perform extracellular recordings from single OSNs by introducing a recording electrode into the sensillum lymph, while the reference electrode is placed in the lymph of the eye or body of the insect. In Drosophila, sensilla house between one and four OSNs, but each OSN typically displays a characteristic spike amplitude. Spike sorting techniques make it possible to assign spiking responses to individual OSNs. This single sensillum recording (SSR) technique monitors the difference in potential between the sensillum lymph and the reference electrode as electrical spikes that are generated by the receptor activity on OSNs1, 2, 8. Changes in the number of spikes in response to the odorant represent the cellular basis of odor coding in insects. Here, we describe the preparation method currently used in our lab to perform SSR on Drosophila melanogaster and Anopheles gambiae, and show representative traces induced by the odorants in a sensillum-specific manner.

Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae

Electrophysiological responses of olfactory sensory neurons to odorants can be measured in insects using single sensillum recordings. In this video article we will demonstrate how to perform single sensillum recordings in the antennae of the vinegar fly (Drosophila melanogaster) and the maxillary palps of the malaria mosquito (Anopheles gambiae).

The sense of smell is essential for insects to find foods, mates, predators, and oviposition sites3. Insect olfactory sensory neurons (OSNs) are enclosed ...

Simultaneous Recording of Calcium Signals from Identified Neurons and Feeding Behavior of Drosophila melanogaster

To study neuronal networks in terms of their function in behavior, we must analyze how neurons operate when each behavioral pattern is generated. Thus, simultaneous recordings of neuronal activity and behavior are essential to correlate brain activity to behavior. For such behavioral analyses, the fruit fly, Drosophila melanogaster, allows us to incorporate genetically encoded calcium indicators such as GCaMP1, to monitor neuronal activity, and to use sophisticated genetic manipulations for optogenetic or thermogenetic techniques to specifically activate identified neurons2-5. Use of a thermogenetic technique has led us to find critical neurons for feeding behavior (Flood et al., under revision). As a main part of feeding behavior, a Drosophila adult extends its proboscis for feeding6 (proboscis extension response; PER), responding to a sweet stimulus from sensory cells on its proboscis or tarsi. Combining the protocol for PER7 with a calcium imaging technique8 using GCaMP3.01, 9, I have established an experimental system, where we can monitor activity of neurons in the feeding center &#x2013; the suboesophageal ganglion (SOG), simultaneously with behavioral observation of the proboscis. I have designed an apparatus ("Fly brain Live Imaging and Electrophysiology Stage": "FLIES") to accommodate a Drosophila adult, allowing its proboscis to freely move while its brain is exposed to the bath for Ca2+ imaging through a water immersion lens. The FLIES is also appropriate for many types of live experiments on fly brains such as electrophysiological recording or time lapse imaging of synaptic morphology. Because the results from live imaging can be directly correlated with the simultaneous PER behavior, this methodology can provide an excellent experimental system to study information processing of neuronal networks, and how this cellular activity is coupled to plastic processes and memory.

Simultaneous Recording of Calcium Signals from Identified Neurons and Feeding Behavior of Drosophila melanogaster

The fruit fly, Drosophila melanogaster, extends its proboscis for feeding, responding to a sugar stimulus from its proboscis or tarsus. I have combined observations of the proboscis extension response (PER) with a calcium imaging technique, allowing us to monitor the activity of neurons in the brain, simultaneously with behavioral observation.

To study neuronal networks in terms of their function in behavior, we must analyze how neurons operate when each behavioral pattern is generated.  Thus, ...

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 ...

Optogenetic Stimulation of Escape Behavior in Drosophila melanogaster

A growing number of genetically encoded tools are becoming available that allow non-invasive manipulation of the neural activity of specific neurons in Drosophila melanogaster1. Chief among these are optogenetic tools, which enable the activation or silencing of specific neurons in the intact and freely moving animal using bright light. Channelrhodopsin (ChR2) is a light-activated cation channel that, when activated by blue light, causes depolarization of neurons that express it. ChR2 has been effective for identifying neurons critical for specific behaviors, such as CO2 avoidance, proboscis extension and giant-fiber mediated startle response2-4. However, as the intense light sources used to stimulate ChR2 also stimulate photoreceptors, these optogenetic techniques have not previously been used in the visual system. Here, we combine an optogenetic approach with a mutation that impairs phototransduction to demonstrate that activation of a cluster of loom-sensitive neurons in the fly's optic lobe, Foma-1 neurons, can drive an escape behavior used to avoid collision. We used a null allele of a critical component of the phototransduction cascade, phospholipase C-&beta;, encoded by the norpA gene, to render the flies blind and also use the Gal4-UAS transcriptional activator system to drive expression of ChR2 in the Foma-1 neurons. Individual flies are placed on a small platform surrounded by blue LEDs. When the LEDs are illuminated, the flies quickly take-off into flight, in a manner similar to visually driven loom-escape behavior. We believe that this technique can be easily adapted to examine other behaviors in freely moving flies.

Optogenetic Stimulation of Escape Behavior in Drosophila melanogaster

Genetically encoded optogenetic tools enable noninvasive manipulation of specific neurons in the Drosophila brain. Such tools can identify neurons whose activation is sufficient to elicit or suppress particular behaviors. Here we present a method for activating Channelrhodopsin2 that is expressed in targeted neurons in freely walking flies.

A  growing number of genetically encoded tools are becoming available that allow non-invasive  manipulation of the neural activity of specific neurons in ...

A Single-fly Assay for Foraging Behavior in Drosophila

For many animals, hunger promotes changes in the olfactory system in a manner that facilitates the search for appropriate food sources. In this video article, we describe an automated assay to measure the effect of hunger or satiety on olfactory dependent food search behavior in the adult fruit fly Drosophila melanogaster. In a light-tight box illuminated by red light that is invisible to fruit flies, a camera linked to custom data acquisition software monitors the position of six flies simultaneously. Each fly is confined to walk in individual arenas containing a food odor at the center. The testing arenas rest on a porous floor that functions to prevent odor accumulation. Latency to locate the odor source, a metric that reflects olfactory sensitivity under different physiological states, is determined by software analysis. Here, we discuss the critical mechanics of running this behavioral paradigm and cover specific issues regarding fly loading, odor contamination, assay temperature, data quality, and statistical analysis.

A Single-fly Assay for Foraging Behavior in Drosophila

In this video article, we describe an automated assay to measure the effect of hunger or satiety on olfactory dependent food search behavior in the adult fruit fly Drosophila melanogaster.

For many animals, hunger promotes changes in the olfactory system in a manner that facilitates the search for appropriate food sources. In this video ...

Straightforward Assay for Quantification of Social Avoidance in Drosophila melanogaster

Drosophila melanogaster is an emerging model to study different aspects of social interactions. For example, flies avoid areas previously occupied by stressed conspecifics due to an odorant released during stress known as the Drosophila stress odorant (dSO). Through the use of the T-maze apparatus, one can quantify the avoidance of the dSO by responder flies in a very affordable and robust assay. Conditions necessary to obtain a strong performance are presented here. A stressful experience is necessary for the flies to emit dSO, as well as enough emitter flies to cause a robust avoidance response to the presence of dSO. Genetic background, but not their group size, strongly altered the avoidance of the dSO by the responder flies. Canton-S and Elwood display a higher performance in avoiding the dSO than Oregon and Samarkand strains. This behavioral assay will allow identification of mechanisms underlying this social behavior, and the assessment of the influence of genes and environmental conditions on both emission and avoidance of the dSO. Such an assay can be included in batteries of simple diagnostic tests used to identify social deficiencies of mutants or environmental conditions of interest.

Straightforward Assay for Quantification of Social Avoidance in Drosophila melanogaster

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.

Drosophila melanogaster is an emerging model to study different aspects of social interactions. For example, flies avoid areas previously occupied by ...

Dyeing Insects for Behavioral Assays: the Mating Behavior of Anesthetized Drosophila

Mating experiments using Drosophila have contributed greatly to the understanding of sexual selection and behavior. Experiments often require simple, easy and cheap methods to distinguish between individuals in a trial. A standard technique for this is CO2 anaesthesia and then labelling or wing clipping each fly. However, this is invasive and has been shown to affect behavior. Other techniques have used coloration to identify flies. This article presents a simple and non-invasive method for labelling Drosophila that allows them to be individually identified within experiments, using food coloring. This method is used in trials where two males compete to mate with a female. Dyeing allowed quick and easy identification. There was, however, some difference in the strength of the coloration across the three species tested. Data is presented showing the dye has a lower impact on mating behavior than CO2 in Drosophila melanogaster. The impact of CO2 anaesthesia is shown to depend on the species of Drosophila, with D. pseudoobscura and D. subobscura showing no impact, whereas D. melanogaster males had reduced mating success. The dye method presented is applicable to a wide range of experimental designs.

Dyeing Insects for Behavioral Assays: the Mating Behavior of Anesthetized Drosophila

This protocol describes a simple, cost effective way to individually identify Drosophila or other insects. Demonstration data investigating mating success across three species of Drosophila show that this method is comparable or better than the use of CO2 anaesthesia.

Mating experiments using Drosophila have contributed greatly to the understanding of sexual selection and behavior. Experiments often require simple, easy ...

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 ...

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic pathways. Quantitative descriptions are rarely performed, although genetic manipulations produce a range of phenotypic effects and variations are observed even among individuals within control groups.&#160;Emerging evidence shows that morphology, size and location of organelles play a previously underappreciated, yet fundamental role in cell function and survival. Here we provide step-by-step instructions for performing quantitative analyses of phenotypes at the Drosophila larval neuromuscular junction (NMJ). We use several reliable immuno-histochemical markers combined with bio-imaging techniques and morphometric analyses to examine the effects of genetic mutations on specific cellular processes. In particular, we focus on the quantitative analysis of phenotypes affecting morphology, size and position of nuclei within the striated muscles of Drosophila larvae. The Drosophila larval NMJ is a valuable experimental model to investigate the molecular mechanisms underlying the structure and the function of the neuromuscular system, both in health and disease. However, the methodologies we describe here can be extended to other systems as well.

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Morphology, size and location of intracellular organelles are evolutionarily conserved and appear to directly affect their function. Understanding the molecular mechanisms underlying these processes has become an important goal of modern biology. Here we show how these studies can be facilitated by the application of quantitative techniques.

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic ...

Using Linear Agarose Channels to Study Drosophila Larval Crawling Behavior

Drosophila larval crawling is emerging as a powerful model to study neural control of sensorimotor behavior. However, larval crawling behavior on flat open surfaces is complex,&#160;including: pausing, turning, and meandering. This complexity in the repertoire of movement hinders detailed analysis of the events occurring during a single crawl stride cycle. To overcome this obstacle, linear agarose channels were made that constrain larval behavior to straight, sustained, rhythmic crawling. In principle, because agarose channels and the Drosophila larval body are both optically clear, the movement of larval structures labeled by genetically-encoded fluorescent probes can be monitored in intact, freely-moving larvae. In the past, larvae were placed in linear channels and crawling at the level of whole organism, segment, and muscle were analyzed1. In the future, larvae crawling in channels can be used for calcium imaging to monitor neuronal activity. Moreover, these methods can be used with larvae of any genotype and with any researcher-designed channel. Thus the protocol presented below is widely applicable for studies using the Drosophila larva as a model to understand motor control.

Using Linear Agarose Channels to Study Drosophila Larval Crawling Behavior

The Drosophila larva is a powerful model system to study neural control of behavior. This publication describes the use of linear agarose channels to elicit sustained bouts of linear crawling and methods to quantify the dynamics of larval structures during repetitive crawling behavior.

Drosophila larval crawling is emerging as a powerful model to study neural control of sensorimotor behavior. However, larval crawling behavior on flat ...