The authors would like to thank Dr. Tingwei Mi for helping them optimize the two-choice feeding assay. They would also like to thank Samuel Chan and Wyatt Koolmees for their comments on the manuscript. This project was funded by the National Institutes of Health grants R03 DC014787 (Y.V.Z.) and R01 DC018592 (Y.V.Z.) and by the Ambrose Monell Foundation.

1. Assembling the assay chambers
NOTE: While this protocol describes the use of a 35 mm Petri dish (Figure 1A), the desired effect can be achieved using any watertight, smooth-bottomed vessel that can be bisected and covered.
<ol>
	<li>First, bisect a lidded 35 mm Petri dish by fixing a length of plastic (5 mm in width and 3 mm in height) down the midline with waterproof adhesive, forming two watertight compartments. Confirm that the seal is complete to avoid le...

<ol>
	<li>Jiao, Y., Moon, S. J., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Drosophila+gustatory+receptor+required+for+the+responses+to+sucrose,+glucose,+and+maltose+identified+by+mRNA+tagging.">A Drosophila gustatory receptor required for the responses to sucrose, glucose, and maltose identified by mRNA tagging.</a> Proceedings of the National Academy of Sciences of the United States of America. 104 (35), 14110-14115 (2007).</li><li>Dahanukar, A., Foster, K., van der Goes van Naters, W. M., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Gr+receptor+is+required+for+response+to+the+sugar+trehalose+in+taste+neurons+of+Drosophila.">A Gr receptor is required for response to the sugar trehalose in taste neurons of Drosophila.</a> Nature Neuroscience. 4 (12), 1182-1186 (2001).</li><li>Ueno, K., 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=Trehalose+sensitivity+in+Drosophila+correlates+with+mutations+in+and+expression+of+the+gustatory+receptor+gene+Gr5a.">Trehalose sensitivity in Drosophila correlates with mutations in and expression of the gustatory receptor gene Gr5a.</a> Current Biology. 11 (18), 1451-1455 (2001).</li><li>Fujii, S., 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=Drosophila+sugar+receptors+in+sweet+taste+perception,+olfaction,+and+internal+nutrient+sensing.">Drosophila sugar receptors in sweet taste perception, olfaction, and internal nutrient sensing.</a> Current Biology. 25 (5), 621-627 (2015).</li><li>Wang, Z., Singhvi, A., Kong, P., Scott, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+representations+in+the+Drosophila+brain.">Taste representations in the Drosophila brain.</a> Cell. 117 (7), 981-991 (2004).</li><li>Thorne, N., Chromey, C., Bray, S., Amrein, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+perception+and+coding+in+Drosophila.">Taste perception and coding in Drosophila.</a> Current Biology. 14 (12), 1065-1079 (2004).</li><li>Slone, J., Daniels, J., Amrein, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sugar+receptors+in+Drosophila.">Sugar receptors in Drosophila.</a> Current Biology. 17 (20), 1809-1816 (2007).</li><li>Dus, 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=Nutrient+sensor+in+the+brain+directs+the+action+of+the+brain-gut+axis+in+Drosophila.">Nutrient sensor in the brain directs the action of the brain-gut axis in Drosophila.</a> Neuron. 87 (1), 139-151 (2015).</li><li>Toshima, N., Tanimura, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+preference+for+amino+acids+is+dependent+on+internal+nutritional+state+in+Drosophila+melanogaster.">Taste preference for amino acids is dependent on internal nutritional state in Drosophila melanogaster.</a> Journal of Experimental Biology. 215 (16), 2827-2832 (2012).</li><li>Melcher, C., Bader, R., Pankratz, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amino+acids,+taste+circuits,+and+feeding+behavior+in+Drosophila:+towards+understanding+the+psychology+of+feeding+in+flies+and+man.">Amino acids, taste circuits, and feeding behavior in Drosophila: towards understanding the psychology of feeding in flies and man.</a> Journal of Endocrinology. 192 (3), 467-472 (2007).</li><li>Zhang, Y. V., Ni, J., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+basis+for+attractive+salt-taste+coding+in+Drosophila.">The molecular basis for attractive salt-taste coding in Drosophila.</a> Science. 340 (6138), 1334-1338 (2013).</li><li>Weiss, L. A., Dahanukar, A., Kwon, J. Y., Banerjee, D., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+and+cellular+basis+of+bitter+taste+in+Drosophila.">The molecular and cellular basis of bitter taste in Drosophila.</a> Neuron. 69 (2), 258-272 (2011).</li><li>Moon, S. J., Kottgen, M., Jiao, Y., Xu, H., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+taste+receptor+required+for+the+caffeine+response+in+vivo.">A taste receptor required for the caffeine response in vivo.</a> Current Biology. 16 (18), 1812-1817 (2006).</li><li>Dweck, H. K. M., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+logic+and+evolution+of+bitter+taste+in+Drosophila.">Molecular logic and evolution of bitter taste in Drosophila.</a> Current Biology. 30 (1), 17-30 (2020).</li><li>Lee, 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=Gustatory+receptors+required+for+avoiding+the+insecticide+L-canavanine.">Gustatory receptors required for avoiding the insecticide L-canavanine.</a> Journal of Neuroscience. 32 (4), 1429-1435 (2012).</li><li>Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+taste+of+the+Drosophila+gustatory+receptors.">A taste of the Drosophila gustatory receptors.</a> Current Opinion in Neurobiology. 19 (4), 345-353 (2009).</li><li>Clyne, P. J., Warr, C. G., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candidate+taste+receptors+in+Drosophila.">Candidate taste receptors in Drosophila.</a> Science. 287 (5459), 1830-1834 (2000).</li><li>Liman, E. R., Zhang, Y. V., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peripheral+coding+of+taste.">Peripheral coding of taste.</a> Neuron. 81 (5), 984-1000 (2014).</li><li>Scott, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gustatory+processing+in+Drosophila+melanogaster.">Gustatory processing in Drosophila melanogaster.</a> Annual Review of Entomology. 63, 15-30 (2018).</li><li>Freeman, E. G., Dahanukar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+neurobiology+of+Drosophila+taste.">Molecular neurobiology of Drosophila taste.</a> Current Opinion in Neurobiology. 34, 140-148 (2015).</li><li>Tanimura, T., Isono, K., Yamamoto, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+sensitivity+to+trehalose+and+its+alteration+by+gene+dosage+in+Drosophila+melanogaster.">Taste sensitivity to trehalose and its alteration by gene dosage in Drosophila melanogaster.</a> Genetics. 119 (2), 399-406 (1988).</li><li>Zhang, Y. V., Raghuwanshi, R. P., Shen, W. L., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Food+experience-induced+taste+desensitization+modulated+by+the+Drosophila+TRPL+channel.">Food experience-induced taste desensitization modulated by the Drosophila TRPL channel.</a> Nature Neuroscience. 16 (10), 1468-1476 (2013).</li><li>Bantel, A. P., Tessier, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+preference+assay+for+adult+Drosophila.">Taste preference assay for adult Drosophila.</a> Journal of Visualized Experiments: JoVE. (115), e54403 (2016).</li><li>Shiraiwa, T., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proboscis+extension+response+(PER)+assay+in+Drosophila.">Proboscis extension response (PER) assay in Drosophila.</a> Journal of Visualized Experiments: JoVE. (3), e193 (2007).</li><li>Ja, W. 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=Prandiology+of+Drosophila+and+the+CAFE+assay.">Prandiology of Drosophila and the CAFE assay.</a> Proceedings of the National Academy of Sciences of the United States of America. 104 (20), 8253-8256 (2007).</li><li>Diegelmann, S., 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+CApillary+FEeder+assay+measures+food+intake+in+Drosophila+melanogaster.">The CApillary FEeder assay measures food intake in Drosophila melanogaster.</a> Journal of Visualized Experiments: JoVE. (121), e55024 (2017).</li><li>Ro, J., Harvanek, Z. M., Pletcher, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FLIC:+high-throughput,+continuous+analysis+of+feeding+behaviors+in+Drosophila.">FLIC: high-throughput, continuous analysis of feeding behaviors in Drosophila.</a> PLoS One. 9 (6), 101107 (2014).</li><li>Yoshihara, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+recording+of+calcium+signals+from+identified+neurons+and+feeding+behavior+of+Drosophila+melanogaster.">Simultaneous recording of calcium signals from identified neurons and feeding behavior of Drosophila melanogaster.</a> Journal of Visualized Experiments: JoVE. (62), e3625 (2012).</li><li>Deshpande, S. A., 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=Quantifying+Drosophila+food+intake:+comparative+analysis+of+current+methodology.">Quantifying Drosophila food intake: comparative analysis of current methodology.</a> Nature Methods. 11 (5), 535-540 (2014).</li><li>Yapici, N., Cohn, R., Schusterreiter, C., Ruta, V., Vosshall, L. 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+taste+circuit+that+regulates+ingestion+by+integrating+food+and+hunger+signals.">A taste circuit that regulates ingestion by integrating food and hunger signals.</a> Cell. 165 (3), 715-729 (2016).</li><li>Jiang, L., Zhan, Y., Zhu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+quantitative+food-intake+assays+and+forcibly+activating+neurons+to+study+appetite+in+Drosophila.">Combining quantitative food-intake assays and forcibly activating neurons to study appetite in Drosophila.</a> Journal of Visualized Experiments: JoVE. (134), e56900 (2018).</li><li>Moon, S. J., Lee, Y., Jiao, Y., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Drosophila+gustatory+receptor+essential+for+aversive+taste+and+inhibiting+male-to-male+courtship.">A Drosophila gustatory receptor essential for aversive taste and inhibiting male-to-male courtship.</a> Current Biology. 19 (19), 1623-1627 (2009).</li><li>Zhang, Y. V., Aikin, T. J., Li, Z., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+basis+of+food+texture+sensation+in+Drosophila.">The basis of food texture sensation in Drosophila.</a> Neuron. 91 (4), 863-877 (2016).</li><li>Itskov, P. 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This method involves several crucial steps where problems can occur. First, make sure flies ingest a sufficient amount of food to provide stable data. If flies eat poorly, ensure that the flies have been wet-starved for at least 24 h, and that the experimental media contains at least a minimal sucrose concentration (2 mM). To further stimulate food consumption, prolong the wet-starvation period beyond 24 h, depending on the flies&#39; physiological condition. If too many flies fail to survive the prolonged starvation, en...

Despite dramatic differences in the anatomical structure of taste organs between flies and mammals, the flies&#39; behavioral responses to many tastant substances are strikingly similar to those of mammals. For example, flies prefer sugar1,2,3,4,5,6,7,8, amino acids9,10, and low salt11, which indicate nutrients, but reject bitter foods12,13,14,15 that are unpalatable or toxic. Over the past two decades, flies have proven to be a highly valuable model organism for advancing the understanding of many fundamental questions related to taste sensation and food consumption, including tastant detection, taste transduction, taste plasticity, and feeding regulation16,17,18,19,20. Remarkably, a number of studies have demonstrated that the taste transduction and neural circuit mechanisms underlying taste perception are analogous between fruit flies and mammals. Therefore, the fruit fly serves as an ideal experimental organism, enabling researchers to uncover evolutionarily conserved concepts and principles that govern food detection and consumption in the animal kingdom.
To investigate taste sensation in flies, it is critical to establish a fast and rigorous assay to objectively measure food preference. Over the years, various feeding methods, such as dye-based assays11,12,13,21,22,23, the fly proboscis extension response assay24, the Capillary Feeder (CAFE) assay25,26, the Fly Liquid-Food Interaction Counter (FLIC) assay27, and other combinatorial methods have been developed to quantitatively measure food preference and/or food intake for fruit flies28,29,30,31. One of the popular feeding paradigms is the dye-based two-choice feeding assay using either a multiwell microtiter plate12,21,32 or, as described here, a small Petri dish11,22 as the feeding chamber. This assay is designed based on the transparency of the fly&#39;s abdomen. During this assay, flies are placed into the feeding chamber and presented with two food options mixed with either red dye or blue dye. Once the assay is complete, fly abdomens appear red or blue depending on which food they have consumed.
Both the Petri-dish and the multiwell-plate dye-based feeding assays are highly robust and yield approximately the same results. Using these two assays, numerous important discoveries and breakthroughs have been made toward deciphering the highly diversified receptors and cells responsible for sensing food tastes and food texture11,12,21,22,32,33. In the dye-based assay, one experimental step requiring considerable time and effort is preparing and loading food into the feeding chamber. To reduce the food preparation and loading time, this assay was modified by replacing the multiwell microtiter plate with a small Petri dish, which is divided into two equal compartments. In the Petri-dish-based assay, two different foods supplemented with blue or red dye are added to the two halves of the dish. Then, ~70 prestarved, 2-4-day-old flies are placed in the dish and allowed to choose between blue and red foods in the dark for about 90 min. The abdomen of each fly is then examined, and the preference index (PI) is calculated.
This Petri-dish-based two-choice feeding assay is affordable, simple, and fast. One multiwell plate requires approximately 110 s to fill, whereas each Petri dish takes only ~20 s. In addition, the multiwell plate requires pipetting small volumes of food into a large number of small wells (e.g., 60 or more wells per plate), which demands considerable precision and attention. Conversely, the Petri-dish-based assay requires only two actions per plate. As the feeding assay can involve a large number of replicates, the Petri-dish-based assay saves a nontrivial amount of time and effort. This assay gives results equivalent to those from the multiwell-based assay and has proven successful in addressing many fundamental questions in taste sensation, including salt taste coding11, taste plasticity modified by food experience22, and the molecular basis of food texture sensation33. In summary, this Petri-dish-based two-choice assay is a powerful tool to investigate how flies perceive external and internal nutrient milieus to elicit appropriate feeding behavior.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>35 mm Petri dish</td>
			<td>Fisher Scientific</td>
			<td>08-772E</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Thomas Scientific</td>
			<td>C756P56</td>
			<td></td>
		</tr>
		<tr>
			<td>Clear adhesive</td>
			<td>Fisher Scientific</td>
			<td>NC9884114</td>
			<td></td>
		</tr>
		<tr>
			<td>Conical centrifuge tubes</td>
			<td>Fisher Scientific</td>
			<td>05-527-90</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection microscope</td>
			<td>Amscope</td>
			<td>SM-2T-6WB-V331</td>
			<td></td>
		</tr>
		<tr>
			<td>FCF Brilliant Blue</td>
			<td>Wako Chemical</td>
			<td>3844-45-9</td>
			<td></td>
		</tr>
		<tr>
			<td>Fly CO2 anesthesia setup</td>
			<td>Genesee Scientfic</td>
			<td>59-114/54-104M</td>
			<td></td>
		</tr>
		<tr>
			<td>Fly incubator with programmable day/night cycle</td>
			<td>Powers Scientific Inc.</td>
			<td>IS33SD</td>
			<td></td>
		</tr>
		<tr>
			<td>Fly lines</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glass dish (microwave-safe)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Kimwipes</td>
			<td>Fisher Scientific</td>
			<td>06-666A</td>
			<td></td>
		</tr>
		<tr>
			<td>Media storage bottle</td>
			<td>Fisher Scientific</td>
			<td>50-192-9998</td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic divider cut to fit the dish from a sheet no thicker than 5 mm</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic fly vials</td>
			<td>Genesee Scientific</td>
			<td>32-116</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Millipore Sigma</td>
			<td>S9378</td>
			<td></td>
		</tr>
		<tr>
			<td>Sulforhodamine B</td>
			<td>Millipore Sigma</td>
			<td>S9012</td>
			<td></td>
		</tr>
		<tr>
			<td>Tastant compound of interest</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex mixer</td>
			<td>Benchmark Scientific</td>
			<td>BV1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>Fisher Scientific</td>
			<td>FSGPD05</td>
			<td></td>
		</tr>
	</tbody>
</table>

a rapid food-preference assay in drosophila

To select food with nutritional value while avoiding the consumption of harmful agents, animals need a sophisticated and robust taste system to evaluate their food environment. The fruit fly, Drosophila melanogaster, is a genetically tractable model organism that is widely used to decipher the molecular, cellular, and neural underpinnings of food preference. To analyze fly food preference, a robust feeding method is needed. Described here is a two-choice feeding assay, which is rigorous, cost-saving, and fast. The assay is Petri-dish-based and involves the addition of two different foods supplemented with blue or red dye to the two halves of the dish. Then, ~70 prestarved, 2-4-day-old flies are placed in the dish and&#160;allowed to choose between blue and red foods in the dark for about 90 min. Examination of the abdomen of each fly is followed by the calculation of the preference index. In contrast to multiwell plates, each Petri dish takes only ~20 s to fill and saves time and effort. This feeding assay can be employed to quickly determine whether flies like or dislike a particular food.

In this assay, a 35 mm dish was divided into two equal feeding compartments, with each half of the dish containing agarose food coupled with either blue or red dye (Figure 1A). To exclude dye bias, the blue and red dye concentrations were carefully refined to yield an approximate &#34;0&#34; PI when only these two dyes were added (Figure 1B). Once the Petri dish was loaded with tested food, ~70 wet-starved, 2-4-day-old adult flies were transferred to the dish, a...

Watch this Scientific Journal Video about A Rapid Food-Preference Assay in Drosophila at JoVE.com

A Rapid Food-Preference Assay in Drosophila

We present a protocol for a two-choice feeding assay for flies. This feeding assay is fast and easy to run and is suitable not only for small-scale laboratory research, but also for high-throughput behavioral screens in flies.

A Rapid Food-Preference Assay in Drosophila

To select food with nutritional value while avoiding the consumption of harmful agents, animals need a sophisticated and robust taste system to evaluate ...

Our protocol is designed to perform a fine assay for the fruit fly, which is a powerful model organism that enables to design for all the genes, receptors, neurons and a neuro-psych heads that are involved in test sensation and food-consumption. Like humans fly like food that tastes:sweet, slightly-salty, slightly-sour or reject food that tastes bitter, too salty or too sour. The power of this technique comes from the speed and convenience.You can test many different flies in a short time PRH without a complex setup. Our method is an excellent, excellent assay for understanding whether flies like a, just like a particular food, as well as how certain gene products influence taste preference. Establishing whether animals accept or reject certain foods can be challenging.Therefore it's important to establish a standard protocol for testing animal taste preference. To prepare starvation vials for the assay, loosely compact a piece of tissue at the bottom of each empty plastic fly vial per fly gene type to be tested. Such that the paper fills this space without forming a dense mass, at about three milliliters of pure water to each vial to completely saturate the tissues without standing water.Taking care that there are no large droplets of excess water on the walls of the vials. Alternatively five milliliters of 1%Agros without sucrose can be substituted for the soaked paper, 24 hours before the experiment carbon dioxide anesthetized two to four day old flies and sort the flies into groups of approximately 70. Then add each group of flies to a starvation vile and label each vial with the genotype and time of starvation initiation.Before performing an experiment, prepare a range of dilutions for each dye using the same food with each different dye color. Combined 0.5 grams of Agros with 50 milliliters of pure water in a microwave safe vessel and heat the Agro solution until it has dissolved stirring as necessary. Dissolve each food component, including sucrose and any experimental compounds in water at a 100 fold or higher concentration of the final tested concentration.And mix the Agro dye and desired experimental compound in conical, polypropylene centrifuge tubes. After mixing place the tubes in the 60 degrees Celsius water bath until distribution and add one milliliter of one color of the experimental food and dye solutions to one side of the first assay dish. Allow the Agros to cool until firm before adding one milliliter of the control food solution, labeled with the second dye color to the other side of the dish.Then repeat the assay dish preparation, with the opposite control and experimental dye solution pair. Use the results to identify two dye concentrations that yield a preference index of zero. When no experimental compound is added.To perform a two-way feeding assay. First temporarily paralyzed one experimental fly vile for three to five minutes on ice until no obvious motor activities such as flying and climbing are observed. Once the flies have been immobilized, gently invert the vial and tap to transfer the flies into the assay chamber then quickly placed the lid onto the chamber.When all of the groups have been transferred move all of the assay chambers to a dark and closed space for 90 minutes. At the end of the assay invert the chambers at a minus 20 degrees Celsius freezer, for about an hour. Before placing each chamber under a stereo microscope to examine the abdominal color of the flies in each experimental group.Count a fly, if the abdomen is more than 50%colored indicating a robust feeding, discard any flies in which the abdomen contains only a tiny food spot, which is indicative of poor eating. When all of the flies have been counted use the equation to quantify the food preference index for each group. In this assay, a 35 millimeter dish was divided into two week we'll feed in compartments containing Agro's food, coupled with red or blue dye.To exclude dye bias, the blue and red dye concentrations were carefully refined to yield an approximate zero preference when only these two dyes were added, 90 minutes after wet starved adult fly loading bly abdominal colors appeared as blue or red. If the animal predominantly consumed blue or red food, respectively, if a fly consumed both blue and red, the abdomen appeared purple. Only flies that ingested a considerable amount of food were scored, while flies with an insufficient food intake were not counted.Comparing this Petri dish based assay to the multi-well plate based assay revealed that the two feeding methods gave essentially the same assaying feeding results in response to sweet, bitter, and salty food in wild type flies. Notably, however it is much faster to prepare and distribute food in a Petri dish than in a 60 well multi-well plate. Be sure to identify what dye concentration to use especially after making a new diet batch.This concentration can be different between fly lines. Our pair today is based two-choice assay is very powerful too. For you asking how the flies, sense both internal-external frame damaged to real state appropriate feeding and behavior.

a-rapid-food-preference-assay-in-drosophila

Research

JoVE Journal

Neuroscience

5.8K ビュー.  Monell Chemical Senses Center. 私たちのプロトコルは、テスト感覚と食物消費に関与するすべての遺伝子、受容体、ニューロンおよび神経精神ヘッドのために設計することを可能にする強力なモデル生物であるフルーツフライのための細かいアッセイを実行するように設計されています。人間のように味わう食べ物のように飛ぶ:甘い、少し塩辛い、少し酸っぱい、または苦い、塩辛すぎる、または酸?...

ビデオ: A Rapid Food-Preference Assay in Drosophila

We present a protocol for a two-choice feeding assay for flies. This feeding assay is fast and easy to run and is suitable not only for small-scale laboratory research, but also for high-throughput behavioral screens in...

the capillary feeder (cafe) assay: a method to track food consumption and preference in drosophila

This video describes the CApillary FEeder, or CAFE, assay, a behavioral method that measures food intake and preference of unrestrained fruit flies. The featured protocol shows how to perform the assay with minimal evaporation from the liquid-filled capillaries used to deliver the food and track its...

The CApillary FEeder (CAFE) Assay: A Method to Track Food Consumption and Preference in Drosophila

taste preference assay for adult drosophila

Taste Preference Assay for Adult Drosophila

Taste is an important sensory process which facilitates attraction to beneficial substances and avoidance of toxic substances.  This protocol describes a simple ingestion assay for determining Drosophila gustatory preference for a given chemical...

Taste Preference Assay for Adult Drosophila

taste preference assay: a method for measuring feeding behavior in drosophila

This video describes the taste preference assay, a behavioral method used to measure attraction or avoidance towards colored solutions that taste differently by assessing the fly&#39;s abdominal coloration after ingestion of the preferred substance. The featured protocol demonstrates the procedure used to measure flies&#39; preference towards solutions of varying sucrose...

Taste Preference Assay: A Method for Measuring Feeding Behavior in Drosophila

temperature gradient assay: a method to test temperature preference in drosophila larvae

Drosophila fruit flies can distinguish small changes in temperature and therefore select environments with favorable thermal conditions. This video describes a behavioral assay that tests the temperature preference of Drosophila larvae on a linear thermal...

Temperature Gradient Assay: A Method to Test Temperature Preference in Drosophila Larvae

light preference assay to study innate and circadian regulated photobehavior in drosophila larvae

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae

Here we describe a light-dark preference test for Drosophila larva. This assay provides information about innate and circadian regulation of light sensing and processing...

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae

drosophila egg-laying preference assay: a method to test decision-making in flies

Drosophila females choose between substrates and select sites that are attractive for egg-laying. This video describes a behavioral assay that tests their decision-making, called the egg-laying preference assay. The featured clip demonstrates the procedure with a custom-built setup, which enables researchers not only to test the behavior of many females at the same time but is also compatible with video recording and optogenetic...

Drosophila Egg-Laying Preference Assay: A Method to Test Decision-Making in Flies

the capillary feeder assay measures food intake in drosophila melanogaster

The CApillary FEeder Assay Measures Food Intake in Drosophila melanogaster

The CApillary FEeder (CAFE) assay is a simple, budget-friendly, highly reliable method for investigating mechanisms underlying food intake. Used with the highly versatile genetic model organism Drosophila melanogaster, it provides a powerful means of gaining new insights into regulatory mechanisms of food...

The CApillary FEeder Assay Measures Food Intake in Drosophila melanogaster

preparation of dyed fly food and constipation assay assessment in drosophila

Preparation of Dyed Fly Food and  Constipation Assay Assessment in Drosophila  

Preparation of Dyed Fly Food and Constipation Assay Assessment in Drosophila

measuring crop motility and food passaging in drosophila

Measuring Crop Motility and Food Passaging in Drosophila

The goal of this protocol is to measure crop contraction and quantify food distribution in the Drosophila...

Measuring Crop Motility and Food Passaging in Drosophila

an inexpensive, scalable behavioral assay for measuring ethanol sedation sensitivity and rapid tolerance in drosophila

An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila

Straightforward assays for measuring ethanol sensitivity and rapid tolerance in Drosophila facilitate the use of this model organism for investigating these important ethanol-related behaviors. Here, a relatively simple, scalable assay for measuring ethanol sensitivity and rapid tolerance in flies is...

An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila

design and analysis of temperature preference behavior and its circadian rhythm in drosophila

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila

We recently identified a novel Drosophila circadian output, temperature preference rhythm (TPR), in which the preferred temperature in flies rises during the day and falls during the night. TPR is regulated independently from another circadian output, locomotor activity. Here&#160;we describe the design and analysis of TPR in...

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila

automated analysis of a nematode population-based chemosensory preference assay

Automated Analysis of a Nematode Population-based Chemosensory Preference Assay

We present a behavior recording setup and protocol that enables automated analysis of the nematode, Caenorhabditis elegans' preference for soluble compounds in a population-based assay. This article describes the construction of a behavior chamber, the behavioral assay protocol, and video analysis software usage.

an automated rapid iterative negative geotaxis assay for analyzing adult climbing behavior in a drosophila model of neurodegeneration

An Automated Rapid Iterative Negative Geotaxis Assay for Analyzing Adult Climbing Behavior in a Drosophila Model of Neurodegeneration

This step-by-step protocol analyzes Drosophila negative geotaxis behavior using an automated multi-cylinder system that hosts hundreds of flies and synchronizes their action by an electric motor. Upon synchronization, fly negative geotaxis behavior is assayed, digitally recorded, and analyzed using the self-designed RflyDetection...

An Automated Rapid Iterative Negative Geotaxis Assay for Analyzing Adult Climbing Behavior in a Drosophila Model of Neurodegeneration

measuring constipation in a drosophila model of parkinson's disease

Author Spotlight: Exploring Non-Motor Symptoms in Parkinson's Disease 

This protocol presents an assay for modeling constipation in an alpha-synuclein based Drosophila model of Parkinson's disease.

Constipation Assays in &lt;em&gt;Drosophila&lt;/em&gt; Flies

https://cloudfront.jove.com/CDNSource/teasers/65966_b.jpg

sucrose preference and novelty-induced hypophagia tests in rats using an automated food intake monitoring system

Sucrose Preference and Novelty-Induced Hypophagia Tests in Rats using an Automated Food Intake Monitoring System

Presented here is a protocol to study depression-like and anhedonic behavior in rats. It combines two well-established behavioral methods, the sucrose preference and novelty-induced hypophagia tests, with an automated food and liquid intake monitoring system, to indirectly investigate rodent behavior using surrogate...

combining quantitative food-intake assays and forcibly activating neurons to study appetite in drosophila

Combining Quantitative Food-intake Assays and Forcibly Activating Neurons to Study Appetite in Drosophila

Quantitative food-intake assays with dyed food provide a robust and high-throughput means to evaluate feeding motivation. Combining the food consumption assay with thermogenetic and optogenetic screens is a powerful approach to investigate the neural circuits underlying appetite in adult Drosophila...

Combining Quantitative Food-intake Assays and Forcibly Activating Neurons to Study Appetite in Drosophila

a single-fly assay for foraging behavior in drosophila

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.

A Single-fly Assay for Foraging Behavior in Drosophila

fat preference: a novel model of eating behavior in rats

Fat Preference: A Novel Model of Eating Behavior in Rats

Dietary fat content influences both energy intake and body fat composition in mammals. By examining rats&#8217; preference for high fat food in a series of choice experiments, it is possible to test genetic differences and pharmacological interventions on their preference for high fat...

a simple technique to assay locomotor activity in drosophila

A Simple Technique to Assay Locomotor Activity in Drosophila

The present protocol assesses the locomotor activity of Drosophila by tracking and analyzing the movement of flies in a hand-made arena using open-source software Fiji, compatible with plugins to segment pixels of each frame based on high-definition video recording to calculate parameters of speed, distance,...

A Simple Technique to Assay Locomotor Activity in Drosophila

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 ...

Appetitive Associative Olfactory Learning in Drosophila Larvae

In the following we describe the methodological details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with genetic interference, provides a handle to analyze the neuronal and molecular fundamentals of specifically associative learning in a simple larval brain.
Organisms can use past experience to adjust present behavior. Such acquisition of behavioral potential can be defined as learning, and the physical bases of these potentials as memory traces1-4. Neuroscientists try to understand how these processes are organized in terms of molecular and neuronal changes in the brain by using a variety of methods in model organisms ranging from insects to vertebrates5,6. For such endeavors it is helpful to use model systems that are simple and experimentally accessible. The Drosophila larva has turned out to satisfy these demands based on the availability of robust behavioral assays, the existence of a variety of transgenic techniques and the elementary organization of the nervous system comprising only about 10,000 neurons (albeit with some concessions: cognitive limitations, few behavioral options, and richness of experience questionable)7-10.
Drosophila larvae can form associations between odors and appetitive gustatory reinforcement like sugar11-14. In a standard assay, established in the lab of B. Gerber, animals receive a two-odor reciprocal training: A first group of larvae is exposed to an odor A together with a gustatory reinforcer (sugar reward) and is subsequently exposed to an odor B without reinforcement 9. Meanwhile a second group of larvae receives reciprocal training while experiencing odor A without reinforcement and subsequently being exposed to odor B with reinforcement (sugar reward). In the following both groups are tested for their preference between the two odors. Relatively higher preferences for the rewarded odor reflect associative learning - presented as a performance index (PI). The conclusion regarding the associative nature of the performance index is compelling, because apart from the contingency between odors and tastants, other parameters, such as odor and reward exposure, passage of time and handling do not differ between the two groups9.

Appetitive Associative Olfactory Learning in Drosophila Larvae

Drosophila larvae are able to associate odor stimuli with gustatory reward. Here we describe a simple behavioral paradigm that allows the analysis of appetitive associative olfactory learning.

In the following we describe the methodological  details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with ...

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.

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 ...

Testing Drosophila Olfaction with a Y-maze Assay

Detecting signals from the environment is essential for animals to ensure their survival. To this aim, they use environmental cues such as vision, mechanoreception, hearing, and chemoperception through taste, via direct contact or through olfaction, which represents the response to a volatile molecule acting at longer range. Volatile chemical molecules are very important signals for most animals in the detection of danger, a source of food, or to communicate between individuals. Drosophila melanogaster is one of the most common biological models for scientists to explore the cellular and molecular basis of olfaction. In order to highlight olfactory abilities of this small insect, we describe a modified choice protocol based on the Y-maze test classically used with mice. Data obtained with Y-mazes give valuable information to better understand how animals deal with their perpetually changing environment. We introduce a step-by-step protocol to study the impact of odorants on fly exploratory response using this Y-maze assay.

Testing Drosophila Olfaction with a Y-maze Assay

We present a choice test to reveal the influence of odorants on Drosophila behavior using a Y-maze assay.

Detecting signals from the environment is essential for animals to ensure their survival. To this aim, they use environmental cues such as vision, ...

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 ...

Alcohol use disorder (AUD) is a serious health challenge. Despite a large hereditary component to AUD, few genes have been unambiguously implicated in their etiology. The fruit fly, Drosophila melanogaster, is a powerful model for exploring molecular-genetic mechanisms underlying alcohol-related behaviors and therefore holds great promise for identifying and understanding the function of genes that influence AUD. The use of the Drosophila model for these types of studies depends on the availability of assays that reliably measure behavioral responses to ethanol. This report describes an assay suitable for assessing ethanol sensitivity and rapid tolerance in flies. Ethanol sensitivity measured in this assay is influenced by the volume and concentration of ethanol used, a variety of previously reported genetic manipulations, and also the length of time the flies are housed without food immediately prior to testing. In contrast, ethanol sensitivity measured in this assay is not affected by the vigor of fly handling, sex of the flies, and supplementation of growth medium with antibiotics or live yeast. Three different methods for quantitating ethanol sensitivity are described, all leading to essentially indistinguishable ethanol sensitivity results. The scalable nature of this assay, combined with its overall simplicity to set-up and relatively low expense, make it suitable for small and large scale genetic analysis of ethanol sensitivity and rapid tolerance in Drosophila.

Straightforward assays for measuring ethanol sensitivity and rapid tolerance in Drosophila facilitate the use of this model organism for investigating these important ethanol-related behaviors. Here, a relatively simple, scalable assay for measuring ethanol sensitivity and rapid tolerance in flies is described.

Alcohol use disorder (AUD) is a serious health challenge. Despite a large hereditary component to AUD, few genes have been unambiguously implicated in ...

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 ...

Olfactory and gustatory perception of the environment is vital for animal survival. The most obvious application of these chemosenses is to be able to distinguish good food sources from potentially dangerous food sources. Gustation requires physical contact with a chemical compound which is able to signal through taste receptors that are expressed on the surface of neurons. In insects, these gustatory neurons can be located across the animal's body allowing taste to play an important role in many different behaviors. Insects typically prefer compounds containing sugars, while compounds that are considered bitter tasting are avoided. Given the basic biological importance of taste, there is intense interest in understanding the molecular mechanisms underlying this sensory modality. We describe an adult Drosophila taste assay which reflects the preference of the animals for a given tastant compound. This assay may be applied to animals of any genetic background to examine the taste preference for a desired soluble compound.

Taste is an important sensory process which facilitates attraction to beneficial substances and avoidance of toxic substances. This protocol describes a simple ingestion assay for determining Drosophila gustatory preference for a given chemical compound.

Olfactory and gustatory perception of the environment is vital for animal survival.  The most obvious application of these chemosenses is to be able to ...

For most animals, feeding is an essential behavior for securing survival, and it influences development, locomotion, health and reproduction. Ingestion of the right type and quantity of food therefore has a major influence on quality of life. Research on feeding behavior focuses on the underlying processes that ensure actual feeding and unravels the role of factors regulating internal energy homeostasis and the neuronal bases of decision-making. The model organism Drosophila melanogaster, with its great variety of genetically traceable tools for labeling and manipulating single neurons, allows mapping of neuronal networks and identification of molecular signaling cascades involved in the regulation of food intake. This report demonstrates the CApillary FEeder assay (CAFE) and shows how to measure food intake in a group of flies for time spans ranging from hours to days. This easy-to-use assay consists of glass capillaries filled with liquid food that flies can freely access and feed on. Food consumption in the assay is accurately determined using simple measurement tools. Herein we describe step-by-step the method from setup to successful execution of the CAFE assay, and provide practical examples to analyze the food intake of a group of flies under controlled conditions. The reader is guided through possible limitations of the assay, and advantages and disadvantages of the method compared to other feeding assays in D. melanogaster are evaluated.

The CApillary FEeder (CAFE) assay is a simple, budget-friendly, highly reliable method for investigating mechanisms underlying food intake. Used with the highly versatile genetic model organism Drosophila melanogaster, it provides a powerful means of gaining new insights into regulatory mechanisms of food intake.

For most animals, feeding is an essential behavior for securing survival, and it influences development, locomotion, health and reproduction. Ingestion of ...

Novel Assay for Cold Nociception in Drosophila Larvae

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory machinery, such as in patients experiencing peripheral neuropathy or injury-induced sensitization, are not well characterized. The genetically tractable Drosophila model has been used to study the cells and genes required for noxious heat detection, which has yielded multiple conserved genes of interest. Little is known however about the cells and receptors important for noxious cold sensing. Although, Drosophila does not survive prolonged exposure to cold temperatures (&#8804;10 &#186;C), and will avoid cool, preferring warmer temperatures in behavioral preference assays, how they sense and possibly avoid noxious cold stimuli has only recently been investigated.
Here we describe and characterize the first noxious cold (&#8804;10 &#186;C) behavioral assay in Drosophila. Using this tool and assay, we show an investigator how to qualitatively and quantitatively assess cold nociceptive behaviors. This can be done under normal/healthy culture conditions, or presumably in the context of disease, injury or sensitization. Further, this assay can be applied to larvae selected for desired genotypes, which might impact thermosensation, pain, or nociceptive sensitization. Given that pain is a highly conserved process, using this assay to further study&#160;thermal nociception will likely glean important understanding of pain processes in other species, including vertebrates.

Novel Assay for Cold Nociception in Drosophila Larvae

Here we demonstrate a novel assay to study cold nociception in Drosophila larvae. This assay utilizes a custom-built Peltier probe capable of applying a focal noxious cold stimulus and results in quantifiable cold-specific behaviors. This technique will allow further cellular and molecular dissection of cold nociception.

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory ...