A sensitive optical-based test method for the locomotor activity of earthworms

Sci Total Environ. 2020 May 1:715:136966. doi: 10.1016/j.scitotenv.2020.136966. Epub 2020 Jan 27.

Abstract

The outdated test methodologies for terrestrial animals have limited the progress of soil ecotoxicology to some extent. To improve the behavioral testing of earthworms, a terrestrial model animal, a sensitive optical-based method for detecting locomotor activity was established. The method measured the fine quantified position offsets of each earthworm in place of a conventional overall response rate, which provided the feasibility for accurate analyses and comparisons. By setting appropriate thresholds, the time proportions of medium and burst states (mid-burdur%) could be an optimized endpoint with an ideal balance in output stability and sensitivity. In addition, we chose the head-end, which is the most flexible part of the earthworm, other than whole body to further elevate the sensitivity in indicating the changed traits. Using octopamine, serotonin, and a serial-dose of lindane exposure, the practice credibility of the test method was validated. Our developed locomotor test method overcame the innate characteristics of the earthworm, and was expected to provide a powerful phenotypic tool for ecological and ecotoxicological studies using earthworms and similar invertebrates.

Keywords: Behavior; Earthworm; Locomotion; Neurotoxicology.

MeSH terms

  • Animals
  • Ecotoxicology
  • Locomotion
  • Oligochaeta*
  • Soil
  • Soil Pollutants

Substances

  • Soil
  • Soil Pollutants