Effect of temperature pre-exposure on the locomotion and chemotaxis of C. elegans.

The effect of temperature pre-exposure on locomotion and chemotaxis of the soil-dwelling nematode Caenorhabditis elegans has been extensively studied. The behavior of C. elegans was quantified using a simple harmonic curvature-based model. Animals showed increased levels of activity, compared to control worms, immediately after pre-exposure to 30 °C. This high level of activity in C. elegans translated into frequent turns by making 'complex' shapes, higher velocity of locomotion, and higher chemotaxis index (CI) in presence of a gradient of chemoattractant. The effect of pre-exposure was observed to be persistent for about 20 minutes after which the behavior (including velocity and CI) appeared to be comparable to that of control animals (maintained at 20 °C). Surprisingly, after 30 minutes of recovery, the behavior of C. elegans continued to deteriorate further below that of control worms with a drastic reduction in the curvature of the worms' body. A majority of these worms also showed negative chemotaxis index indicating a loss in their chemotaxis ability.