Overview of Chemotaxis Behavior Assays in Caenorhabditis elegans

Environmental pollution related to anthropogenic pressures, and the associated repercussions on public health, represent a worldwide problem. Thus, the study of the effects that environmental contaminants can pose to natural ecosystems and human health is of vital importance. Laboratory model organisms such as Caenorhabditis elegans have played a significant role in clarifying multilevel effects of those agents. Although the evaluation of contaminant effects at the behavioral level of organisms is an emerging approach in ecotoxicology, studies assessing chemotaxis behavior in C. elegans within the ecotoxicological research context are still scarce. Chemotaxis studies in C. elegans have contributed to the understanding of both the neuronal mechanisms involved in the behavioral effects triggered by environmental cues and the impact of contaminants on natural ecosystems. Its compact and well-characterized nervous system, as well as the availability of transgenic strains and molecular tools, allows a detailed examination of behavioral, molecular, and genetic chemosensation mechanisms. This overview provides a summary and general comparison of methods used to measure chemotaxis behavior in C. elegans, with the aim of helping researchers select the most suitable approach in their chemotaxis studies. We compare methods based on the type of chemical tested, advantages and drawbacks of the different approaches, and specific experimental goals. Lastly, we hope to encourage the evaluation of C. elegans chemotaxis behavior in ecotoxicology studies, as well as its potential integration in standardized protocols assessing environmental quality. © 2021 Wiley Periodicals LLC.