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A Novel Method for Tracking Individuals of Fruit Fly Swarms Flying in a Laboratory Flight Arena.

Cheng XE, Qian ZM, Wang SH, Jiang N, Guo A, Chen YQ - PLoS ONE (2015)

Bottom Line: We found that there exists an asymptotic distance between fruit flies in swarms as the population density increases.Further, we discovered the evidence for repulsive response when the distance between fruit flies approached the asymptotic distance.Overall, the proposed tracking system presents a powerful method for studying flight behaviours of fruit flies in a three-dimensional environment.

View Article: PubMed Central - PubMed

Affiliation: School of Computer Science, Shanghai Key Laboratory of Intelligent Information Processing, Fudan University, Shanghai, China; Jingdezhen Ceramic Institute, Jingdezhen, China.

ABSTRACT
The growing interest in studying social behaviours of swarming fruit flies, Drosophila melanogaster, has heightened the need for developing tools that provide quantitative motion data. To achieve such a goal, multi-camera three-dimensional tracking technology is the key experimental gateway. We have developed a novel tracking system for tracking hundreds of fruit flies flying in a confined cubic flight arena. In addition to the proposed tracking algorithm, this work offers additional contributions in three aspects: body detection, orientation estimation, and data validation. To demonstrate the opportunities that the proposed system offers for generating high-throughput quantitative motion data, we conducted experiments on five experimental configurations. We also performed quantitative analysis on the kinematics and the spatial structure and the motion patterns of fruit fly swarms. We found that there exists an asymptotic distance between fruit flies in swarms as the population density increases. Further, we discovered the evidence for repulsive response when the distance between fruit flies approached the asymptotic distance. Overall, the proposed tracking system presents a powerful method for studying flight behaviours of fruit flies in a three-dimensional environment.

No MeSH data available.


The NND distributions.The PDFs are represented by normalized histograms. (a) The PDFs ofNND distributions of all configurations. (b) The comparison between the PDFs of NND distributions of T03 and the correspondent simulation (random particles). (c) The relationship between the average NND and the population densities at each moment of all configurations. (d) The average NND y as a power function of the population density x.
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pone.0129657.g007: The NND distributions.The PDFs are represented by normalized histograms. (a) The PDFs ofNND distributions of all configurations. (b) The comparison between the PDFs of NND distributions of T03 and the correspondent simulation (random particles). (c) The relationship between the average NND and the population densities at each moment of all configurations. (d) The average NND y as a power function of the population density x.

Mentions: Even when hundreds of fruit flies were free-flying in the arena at the same time, no collision was ever observed. We speculate that the spatial organization of fruit flies may manifest the social structures. The clearest characterization of the spatial structure of fruit flies within a swarm is the probability distribution of the nearest-neighbour distance. The nearest-neighbour distance is the minimum Euclidean distance between a fruit fly and other fruit flies in a swarm. In the later text, we refer to the nearest-neighbour distance as NND. Table 1 shows the number of NNDs of each configuration. At each moment, there were many fruit flies landing on walls of the arena. Therefore, in order to avoid the bias introduced by those landing fruit flies (i.e. edge effects), we ignored a fly’s motion data if its distance to any walls of the arena is less than 20 mm. Fig 7a shows the PDFs of NND distributions of all configurations. It shows that the average NND and the deviation decrease as the population size increases. Moreover, considering the population size of T05 is larger than that of T04, the similar PDFs of T04 and T05 indicate there exists an asymptotic saturation against the increasing population size.


A Novel Method for Tracking Individuals of Fruit Fly Swarms Flying in a Laboratory Flight Arena.

Cheng XE, Qian ZM, Wang SH, Jiang N, Guo A, Chen YQ - PLoS ONE (2015)

The NND distributions.The PDFs are represented by normalized histograms. (a) The PDFs ofNND distributions of all configurations. (b) The comparison between the PDFs of NND distributions of T03 and the correspondent simulation (random particles). (c) The relationship between the average NND and the population densities at each moment of all configurations. (d) The average NND y as a power function of the population density x.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4470659&req=5

pone.0129657.g007: The NND distributions.The PDFs are represented by normalized histograms. (a) The PDFs ofNND distributions of all configurations. (b) The comparison between the PDFs of NND distributions of T03 and the correspondent simulation (random particles). (c) The relationship between the average NND and the population densities at each moment of all configurations. (d) The average NND y as a power function of the population density x.
Mentions: Even when hundreds of fruit flies were free-flying in the arena at the same time, no collision was ever observed. We speculate that the spatial organization of fruit flies may manifest the social structures. The clearest characterization of the spatial structure of fruit flies within a swarm is the probability distribution of the nearest-neighbour distance. The nearest-neighbour distance is the minimum Euclidean distance between a fruit fly and other fruit flies in a swarm. In the later text, we refer to the nearest-neighbour distance as NND. Table 1 shows the number of NNDs of each configuration. At each moment, there were many fruit flies landing on walls of the arena. Therefore, in order to avoid the bias introduced by those landing fruit flies (i.e. edge effects), we ignored a fly’s motion data if its distance to any walls of the arena is less than 20 mm. Fig 7a shows the PDFs of NND distributions of all configurations. It shows that the average NND and the deviation decrease as the population size increases. Moreover, considering the population size of T05 is larger than that of T04, the similar PDFs of T04 and T05 indicate there exists an asymptotic saturation against the increasing population size.

Bottom Line: We found that there exists an asymptotic distance between fruit flies in swarms as the population density increases.Further, we discovered the evidence for repulsive response when the distance between fruit flies approached the asymptotic distance.Overall, the proposed tracking system presents a powerful method for studying flight behaviours of fruit flies in a three-dimensional environment.

View Article: PubMed Central - PubMed

Affiliation: School of Computer Science, Shanghai Key Laboratory of Intelligent Information Processing, Fudan University, Shanghai, China; Jingdezhen Ceramic Institute, Jingdezhen, China.

ABSTRACT
The growing interest in studying social behaviours of swarming fruit flies, Drosophila melanogaster, has heightened the need for developing tools that provide quantitative motion data. To achieve such a goal, multi-camera three-dimensional tracking technology is the key experimental gateway. We have developed a novel tracking system for tracking hundreds of fruit flies flying in a confined cubic flight arena. In addition to the proposed tracking algorithm, this work offers additional contributions in three aspects: body detection, orientation estimation, and data validation. To demonstrate the opportunities that the proposed system offers for generating high-throughput quantitative motion data, we conducted experiments on five experimental configurations. We also performed quantitative analysis on the kinematics and the spatial structure and the motion patterns of fruit fly swarms. We found that there exists an asymptotic distance between fruit flies in swarms as the population density increases. Further, we discovered the evidence for repulsive response when the distance between fruit flies approached the asymptotic distance. Overall, the proposed tracking system presents a powerful method for studying flight behaviours of fruit flies in a three-dimensional environment.

No MeSH data available.