C. elegans Foraging (Roaming–Dwelling)

Foraging assays score how C. elegans allocates its time between exploring an agar plate and exploiting bacterial food. A feeding animal spontaneously alternates between two discrete behavioral states — roaming, a fast and weakly turning state that disperses the animal, and dwelling, a slow and highly turning state associated with local feeding. Ben Arous, Laffont and Chatenay (2009) introduced a quantitative two-state framework for this behavior and showed it is tightly tuned by food concentration.

The roaming–dwelling balance is set by neuromodulation. Fujiwara, Sengupta and McIntire (2002) linked the EGL-4 cGMP-dependent protein kinase to dwelling, and serotonergic and neuropeptide (for example PDF) signaling have since been shown to push the animal into one state or the other, making foraging a sensitive read-out of internal state, satiety and food-related decision-making. Food-leaving assays add a complementary measure of how readily an animal abandons a known food source.

ConductVision classifies roaming and dwelling automatically by combining instantaneous speed with angular velocity over a sliding window, the standard joint criterion for the two states, and tracks each animal’s residence on and departures from defined food patches. Exploration area, state-transition rates and bout durations are exported per animal and per population, with state-coded trajectory overlays for visualization.

The assay is used to study foraging decisions, neuromodulatory control of behavioral state, and satiety, and it supports compound screens that target serotonergic and dopaminergic signaling. Lawn geometry, bacterial density and the animal’s feeding history strongly shape the roaming–dwelling balance, so these should be matched across conditions; throughput is high since many animals can be followed on a single patterned plate.