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A sensitive optical-based test method for the locomotor activity of earthworms
- Xu, Ting, Zhao, Wanting, Miao, Juanjuan, Zhang, Bin, Yang, Xinyue, Sheng, G. Daniel, Yin, Daqiang
- The Science of the total environment 2020 v.715 pp. 136966
- earthworms, ecotoxicology, lindane, locomotion, models, octopamine, phenotype, serotonin, soil
- The outdated test methodologies for terrestrial animals have limited the progress of soil ecotoxicology to some extent.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.