Using Track3D for insects

It is hard to overestimate the importance of insects. In the USA alone, insect pollinators contribute $30 billion to farm income [1] annually. Factors such as the Varroa mite and pesticides, affecting honey bee behavior and surival can have a big economic impact. A lot of wildlife is mostly or totally dependent on eating insects, from birds like woodpeckers, to mammals like hedgehogs and bats, to most reptiles and amphibians. Every year something like a million people are killed by malaria [2], a single swarm of locusts can eat the same quantify of food in one day as 15 million people in the same period [3] and termites emit something like 20-40 Tg of the highly potent greenhouse gas methane to the atmosphere every year [4]. The study of insects' behavior has never been more important.

Track3D insects
The study of insect behavior has never been more important. 
Track 3D
3D tracking gives you the most accurate representation of insect flying behavior. 

Measuring flying

Video tracking has significant advantages over manual recording of behaviors. Video tracking gives accurate information about behaviors such as speed of flying, and the duration the animal was within a zone. It also enables you to carry out objective and unbiased observations and you can make uninterrupted observations over longer periods of time without a break. However, interpretation of the results of video tracking was difficult for animals that fly, swim, or climb. Traditional video tracking only measures the path in 2D, so when an animal moves in three dimensions, information is lost. If a mosquito flies directly up towards an overhead camera, the video tracking software does not measure that movement. For instance, if you want to study how mosquitoes use odor to search for humans, or the affectivity of a pheromone in attracting a butterfly whose caterpillars damage crops (such as the cabbage white butterfly on the right), then research into how the insects' flight path is related to an odor plume is an important tool. Likewise, if you want to study how a plant attracts a pollinating insect, or how parasitic wasps used in biological pest control seek out their hosts, there is no substitute for measuring its flight path in all three dimensions.

Using Track3D

Track3D is a solution which uses the established power of the standard tools Media Recorder and EthoVision XT, together with a special software tool to create 3D visualizations and statistics of the flying path of the insect. During the experiment, two video cameras, placed at different angles to the tank, record the insect's flying in a wind tunnel to video files. The experiment can also be done in the dark, with infra-red light. The video files are then processed automatically in EthoVision XT using batch acquisition. The output of EthoVision is then fed into Track3D, which creates 3D (x, y, z) track files, which the software visualizes and analyzes.

Track3D visualization of your track.

Track3D Output

Visualization

You can view your tracks in a 3D visualization, which you can rotate to see from any direction, pan, and zoom. The movement of the animals' position can be played back as an animation. You can export the animation as a movie file, as well as print it. In the image below, the red trail is the track of an Anopheles gambiae mosquito and the cone of circles indicate the location of an odor plume within the wind tunnel [5]. 

Analysis

Track3D calculates a large quantity of parameters, including:

  • Measures of activity such as total distance travelled and flying speed.
  • Searching behavior can be investigated with tortuosity (taking all three dimensions into account) and a number of other path-shape parameters including angular velocity, course (expressed in relation to the air speed and direction) and drift (change in 3D heading due to the wind).
  • Activity in relation to the plume (including definition of a buffer zone around the plume).
  • Location-based behavior in relation to 3D zones (cones, cuboids and cylinders).

Contact us

If you are interested in a Track3D solution for tracking insects (or anything else that moves in three dimensions), please get in touch with us.

References

[1] Calderone NW (2012) Insect Pollinated Crops, Insect Pollinators and US Agriculture: Trend Analysis of Aggregate Data for the Period 1992–2009. PLoS ONE 7(5): e37235. doi:10.1371/journal.pone.0037235

[2] http://en.wikipedia.org/wiki/Malaria

[3] Smithsonian Blog

[4] Lenard Milich (1999), The role of methane in global warming: where might mitigation strategies be focused?, Global Environmental Change, 9, 179-201

[5] Spitzen, J., Spoor, C.W., Grieco, F., ter Braak, C., Beeuwkes, J., et al. (2013). A 3D Analysis of Flight Behavior of Anopheles gambiae sensu stricto Malaria Mosquitoes in Response to Human Odor and Heat. PLoS ONE 8(5): e62995. doi:10.1371/journal.pone.0062995

Acknowledgements

Track3D has been developed in collaboration with the research groups of Prof. Willem Takken (Laboratory of Entomology) and Prof. Johan van Leeuwen (Experimental Zoology Group) of Wageningen University, The Netherlands.