The authors want to thank Dr. Tadmiri Venkatesh for his encouragement to prepare this manuscript, Dova Brenman and Selwyn Chui for their constructive comments, Elyssa Burg and Wayne Rasband for designing the macro in ImageJ for all interfly distances and for nearest neighbor distances. The authors also want to thank the reviewers for their constructive comments.
A.A.A, M.C.C. and A.F.S were responsible for research design; S.N.J., A.A.A, M.N., Z.R., and A.J.M. performed the experiments. A.A.A, M.N., A.J.M. and M.C.C and A.F.S. analyzed the data; A.R.M. and A.F.S. wrote the manuscript.
This work was supported by PSC-CUNY research awards, jointly funded by The Professional Staff Congress and The City University of New York to A.F.S.; by internal funding from Western University to A.F.S.; by a Mathematics, Biology, Chemistry, and Geology majors scholarship for teachers-in-training and by a Louis Stokes Alliance for Minority Participation scholarship to A.A.A.

1. Equipment and Reagents Created In-house (See List of Materials for Others)
<ol>
	<li>Prepare a Drosophila cold anesthesia apparatus as previously described 8.</li>
	<li>Prepare a fly aspirator as previously described 13.</li>
	<li>Prepare social space chambers and holders.
	<ol>
		<li>Order or make glass panes and acrylic spacers to create the social space chambers. Each social space chamber consists of two square glass panes (17.6 cm by 17.6 cm, with a thickness of 0.3 cm), two right ...

<ol>
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The authors declare that they have no competing financial interests.

In this protocol, a detailed procedure for the quantification of social space was described. Some crucial steps to ensure the experiment is successful are: 1) always use gloves when cleaning and setting up the apparatus, to keep your own oils and scents off the inner chamber of the apparatus, 2) ensure flies are collected at least one day before the experiment to reduce any potential effects of cold anesthesia, 3) 2 hr before the experiment provide new vials containing fresh food to ensure the flies are not starved, and ...

Social interactions are crucial to the proper development and health of individuals within a group as a whole, and can be observed across numerous species, from humans (Homo sapiens) to simpler organisms such as fruit flies (Drosophila melanogaster) 5,6. An individual fruit fly or human share common means to process sensory information during these interactions, whether it be: auditory, visual, olfactory, tactile, or gustation. We and others hypothesize that there is a potentially shared neurocircuitry underlying behavioral responses to social interactions and that the neuronal cells and genes involved might be evolutionary conserved 7. Once the initial interaction has occurred, social space between the interacting individuals will either increase (social avoidance 8) or decrease (group formation/aggregation 5). More complicated interactions, like aggression or courtship, can then take place.
Neither sophisticated tools and methods, nor large investments in time and training are required to quantify this simple form of social behavior, making it a powerful analytical tool. Here, we explain a straightforward protocol that quantifies inter-fly distance, or social space, to assess social interaction in stable groups of Drosophila melanogaster, as used in the following studies 1-4,9. Social space refers to a measure of the distance between a fly and its closest neighbor 10. Social space is consistent for a given population of D. melanogaster when experimental conditions are preserved (averaging approximately within 1-2 body lengths), and varies with respect to the social experience of the flies, increasing if the individual has been kept in isolation 1. Proper vision is necessary to maintain normal social distance, but not classical odorants or cVA perception 1. Measure of social space can thus be used as a diagnostic tool to analyze social interactions and quantify social behavior in D. melanogaster 1. We describe here in details how to perform this quantification, and to what extent common experimental variables affect this behavior.
We show that the orientation of the chamber in which the assay is performed, as well as the number of flies &#8212; to an extent &#8212; do affects social space. It was previously shown that chamber geometry affects spontaneous exploratory movement of flies 11,12, and this phenomena may ultimately impact where they decide to settle. However, as long as the fly density (fly / cm2) and chamber orientation is kept the same, the social space of the flies also remains constant. The robustness of this assay is illustrated by the fact that independent laboratories using different chamber sizes, shape, and orientation can replicate the result displayed by mutants of the white gene (affecting eye pigmentation), which is an increase social space (vertical triangle or horizontal circle in 1, horizontal square with airflow in 3).
Our results also indicate that maintaining the time at which the social space experiment is performed is crucial to the consistency of the results, as we show that males, but not females, are further apart in the evenings. However, the differences seen between daytime and evening hours are not due to activity differences of the flies, and we discuss arguments indicating that activity levels are not correlated with social space.
Finally, there are genetic underpinnings to the determination of social space, as indicated by the white mutant already described 1,3, and the differences between various inbred and wild-caught strains of flies that we present here.
Therefore, this assay makes an excellent tool for studying the effects of genetic as well as environmental factors.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Stereo Zoom Microscope&#160;</td>
			<td>Nikon&#160;&#160;</td>
			<td>SMZ-645</td>
			<td>Any other standard scope for fly handling would work</td>
		</tr>
		<tr>
			<td>Small paint brushes&#160;</td>
			<td></td>
			<td></td>
			<td>for pushing flies</td>
		</tr>
		<tr>
			<td>Jazz-mix</td>
			<td>Fisher</td>
			<td>33545</td>
			<td>any other standard drosophila food would work</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mini-Alarm Timer/Stopwatch</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;Sharpie pens</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adhesive Tape</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Medium size binder clips</td>
			<td>Staples</td>
			<td></td>
			<td>to hold the chambers together: 1-1/4&#34; (32mm) medium clips with 5/8&#34; capacity</td>
		</tr>
		<tr>
			<td>small SupportStands</td>
			<td>Carolina&#160;</td>
			<td>707161</td>
			<td rowspan="2">to hold the chambers in a vertical orientation</td>
		</tr>
		<tr>
			<td>Buret clamps</td>
			<td>Carolina</td>
			<td>707362</td>
		</tr>
		<tr>
			<td>Digital Camera</td>
			<td>Nikon</td>
			<td>&#160;Coolpix S8000&#160;</td>
			<td>to take the still pictures</td>
		</tr>
		<tr>
			<td>small ruler</td>
			<td></td>
			<td></td>
			<td>to be able to scale the picture</td>
		</tr>
		<tr>
			<td>trifold board and white bench cover</td>
			<td></td>
			<td></td>
			<td>to provide a white background, and a homogeneous light.</td>
		</tr>
		<tr>
			<td>pounding pad</td>
			<td></td>
			<td></td>
			<td>any mouse pad works.</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Prism 6</td>
			<td>GraphPad Software Inc.</td>
			<td>Prism 6 for Mac OS X</td>
			<td>Any statistical analysis software with t-test, one-way and two ANOVA would work</td>
		</tr>
	</tbody>
</table>

conditions affecting social space in drosophila melanogaster

The social space assay described here can be used to quantify social interactions of Drosophila melanogaster &#8212; or other small insects &#8212; in a straightforward manner. As we previously demonstrated 1, in a two-dimensional chamber, we first force the flies to form a tight group, subsequently allowing them to take their preferred distance from each other. After the flies have settled, we measure the distance to the closest neighbor (or social space), processing a static picture with free online software (ImageJ). The analysis of the distance to the closest neighbor allows researchers to determine the effects of genetic and environmental factors on social interaction, while controlling for potential confounding factors. Diverse factors such as climbing ability, time of day, sex, and number of flies, can modify social spacing of flies. We thus propose a series of experimental controls to mitigate these confounding effects. This assay can be used for at least two purposes. First, researchers can determine how their favorite environmental shift (such as isolation, temperature, stress or toxins) will impact social spacing 1,2. Second, researchers can dissect the genetic and neural underpinnings of this basic form of social behavior 1,3. Specifically, we used it as a diagnostic tool to study the role of orthologous genes thought to be involved in social behavior in other organisms, such as candidate genes for autism in humans 4.

The social space chamber can be used as a tool to quantify the social behavior of Drosophila melanogaster. Acrylic spacers and glass panes are clipped together to form an inner triangular arena that provides a two-dimensional area in which flies can form stable groups without the presence of many potentially confounding cues. When flies are transferred to the vertical arena, they are startled by being tapped down, and they respond by an escape behavior: negative geotaxis. They climb to the vertex of the upright ...

Watch this Scientific Journal Video about Conditions Affecting Social Space in Drosophila melanogaster at JoVE.com

Conditions Affecting Social Space in Drosophila melanogaster

The effect of genes and environment on social space of Drosophila melanogaster can be quantified through a powerful but straightforward analytical paradigm. We show here different factors that can affect this social space, and thus need to be taken into consideration when designing experiments in this paradigm.

Conditions Affecting Social Space in Drosophila melanogaster

The social space assay described here can be used to quantify social interactions of Drosophila melanogaster &#8212; or other small insects &#8212; in a ...

conditions-affecting-social-space-in-drosophila-melanogaster

Research

JoVE Journal

Neuroscience

12.0K Görüntüleme.  University of Western Ontario. The effect of genes and environment on social space of Drosophila melanogaster can be quantified through a powerful but straightforward analytical paradigm. We show here different factors that can affect this social space, and thus need to be taken into consideration when designing experiments in this paradigm.