About 100 worms from strain AF16 raised at 23°C and placed at the center of a plate with no temperature gradient. This is an example of how the worms randomly explore a blank plate and is used as a control for experiments with a linear temperature gradient across a plate. Worms are crawling on standard agar plates for nematode worms. This video was filmed at 1fps but played back at 40fps. Comet tails show the worms position over 30 seconds of video.

In this video Caenorhabditis briggsae worms can be seen following lines perpendicular to a temperature gradient (19°C on the right to 27°C on the left), this is because worms are tracking isothermal lines on the agar plate. They tend to track longer lines and do this behaviour more often when they are near their cultivation temperature (23°C in this case - at the center of the plate). This was filmed at 0.5fps over 25 minutes, comet tails show worms position over one minute of video.

This is an example video of C. briggsae worms swimming in a four droplets with a temperature gradient running from cold at the top to warm at the bottom. The gradient steepness is approximately 2°C/cm and each drop is about 4mm across. This video is a time lapse of one image per 8 seconds.

In this video about 100 worms from strain N2 raised at 23°C and placed at the center of a linear temperature gradient from 23°C on the left to 17°C on the right, accumulate towards the warmer 23°C end of the plate. This is expected as this temperature is associated with food, however this is different than what I see in some strains of C. briggsae which seem to always prefer cryophilic thermotaxis. Worms are crawling on standard agar plates for nematode worms. This video was filmed at 1fps but played back at 40fps. Comet tails show the worms position over 30 seconds of video.

In this video about 100 worms from strain AF16 raised at 23°C and placed at the center of a linear temperature gradient from 23°C on the left to 17°C on the right, accumulate towards the colder 17°C end of the plate. This is different than what is seen in other strains, where worms will move towards the warmer end corresponding to cultivation temperature and associated with food. Worms are crawling on standard agar plates for nematode worms. This video was filmed at 1fps but played back at 40fps. Comet tails show the worms position over 30 seconds of video.