Open Source Tracking and Analysis of Adult Drosophila Locomotion in Buridan's Paradigm with and without Visual Targets

Abstract

BackgroundInsects have been among the most widely used model systems for studying the control of locomotion by nervous systems. In Drosophila, we implemented a simple test for locomotion: in Buridan's paradigm, flies walk back and forth between two inaccessible visual targets [1]. Until today, the lack of easily accessible tools for tracking the fly position and analyzing its trajectory has probably contributed to the slow acceptance of Buridan's paradigm.Methodology/Principal FindingsWe present here a package of open source software designed to track a single animal walking in a homogenous environment (Buritrack) and to analyze its trajectory. The Centroid Trajectory Analysis (CeTrAn) software is coded in the open source statistics project R. It extracts eleven metrics and includes correlation analyses and a Principal Components Analysis (PCA). It was designed to be easily customized to personal requirements. In combination with inexpensive hardware, these tools can readily be used for teaching and research purposes. We demonstrate the capabilities of our package by measuring the locomotor behavior of adult Drosophila melanogaster (whose wings were clipped), either in the presence or in the absence of visual targets, and comparing the latter to different computer-generated data. The analysis of the trajectories confirms that flies are centrophobic and shows that inaccessible visual targets can alter the orientation of the flies without changing their overall patterns of activity.Conclusions/SignificanceUsing computer generated data, the analysis software was tested, and chance values for some metrics (as well as chance value for their correlation) were set. Our results prompt the hypothesis that fixation behavior is observed only if negative phototaxis can overcome the propensity of the flies to avoid the center of the platform. Together with our companion paper, we provide new tools to promote Open Science as well as the collection and analysis of digital behavioral data.

Sub-strains of Drosophila Canton-S differ markedly in their locomotor behavior

“…We tested them in two replicates in two consecutive years using different hardware and under slightly varying experimental details (see Materials and Methods). The locomotion parameters that we calculated can be divided into three broad categories: temporal (activity/pause structure), spatial (stripe fixation, thigmotaxis, trajectory straightness) and mixed (speed, number of walks between stripes, distance travelled) measures ( Table 1 7 ). Flies’ walking behavior was also visualized in transition plots, where the frequency of passage at each platform position is indicated by a heatmap.…”

“…We performed 5 minute long walking experiments with five different wild type Canton S (CS) sub-strains: CS_TP, CS_TZ, CS_JC, CS_BS and CS_HS. The locomotion parameters we calculated can be divided into three broad categories: temporal (activity/pause structure), spatial (stripe fixation, thigmotaxis, trajectory straightness) and mixed (speed, number of walks between stripes, distance travelled) measures ( Table 1) 7 .…”

A decision underlies phototaxis in an insect

“…Locomotion towards dark objects was evaluated using Buridan's paradigm as explained by Colomb et al [35]. Briefly, 3-6-day-old flies were selected and half of them had their wings clipped under CO 2 anaesthesia (http://dx.doi.org/10.…”

“…Buridan's paradigm, where the flies walk on a water-surrounded circular platform with two opposing vertical black stripes on the walls of a round panorama illuminated in bright white light from behind, has been used as a standard test for walking speed and locomotor activity for several decades [35,40]. We compared total activity time, walking speed and pause duration in intact and wingless flies from three lines (WTB, CyO, PKC d ) in a modified version of Buridan's paradigm, where a roof prevents the flies from escaping.…”

Measuring individual locomotor rhythms in honey bees, paper wasps and similar sized insects

“…Although there are currently various methods to record locomotor activity, such as video recordings combined with video-tracking systems (Colomb et al, 2012;Donelson et al, 2012;Gilestro, 2012), infrared-based systems such as the Trikinetics system are still the most commonly used. In general, infrared-based systems for measuring locomotor activity require the following components: (1) a chamber with an infrared beam that detects activity as the number of beam interruptions, (2) an interphase that will collect the data from the chamber and send it to a computer, (3) data acquisition software to translate the interphase data into readable files, and (4) data analysis software to calculate the different circadian parameters (period, phase, rhythm strength, etc.…”