title: Automated analysis of two-dimensional positions and body lengths of earthworms (Oligochaeta); MimizuTrack.
abstract: Earthworms are important soil macrofauna inhabiting almost all ecosystems. Their biomass is large and their burrowing and ingestion of soils alters soil physicochemical properties. Because of their large biomass, earthworms are regarded as an indicator of "soil heath". However, primarily because the difficulties in quantifying their behavior, the extent of their impact on soil material flow dynamics and soil health is poorly understood. Image data, with the aid of image processing tools, are a powerful tool in quantifying the movements of objects. Image data sets are often very large and time-consuming to analyze, especially when continuously recorded and manually processed. We aimed to develop a system to quantify earthworm movement from video recordings. Our newly developed program successfully tracked the two-dimensional positions of three separate parts of the earthworm and simultaneously output the change in its body length. From the output data, we calculated the velocity of the earthworm's movement. Our program processed the image data three times faster than the manual tracking system. To date, there are no existing systems to quantify earthworm activity from continuously recorded image data. The system developed in this study will reduce input time by a factor of three compared with manual data entry and will reduce errors involved in quantifying large data sets. Furthermore, it will provide more reliable measured values, although the program is still a prototype that needs further testing and improvement. Combined with other techniques, such as measuring metabolic gas emissions from earthworm bodies, this program could provide continuous observations of earthworm behavior in response to environmental variables under laboratory conditions. In the future, this standardized method will be applied to other animals, and the quantified earthworm movement will be incorporated into models of soil material flow dynamics or behavior in response to chemical substances present in the soil.
authors.affiliation: National Institute for Agro-Environmental Sciences (NIAES), 3-1-3 Kannondai, Tsukuba, Ibaraki, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Kodama
authors.affiliation: School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: National Institute for Agro-Environmental Sciences (NIAES), 3-1-3 Kannondai, Tsukuba, Ibaraki, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Yonemura
authors.affiliation: National Institute for Agro-Environmental Sciences (NIAES), 3-1-3 Kannondai, Tsukuba, Ibaraki, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kaneda
authors.affiliation: School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo, Japan.
authors.forename: Mizue
authors.initials: M
authors.lastname: Ohashi
authors.affiliation: School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ikeno
mesh_terms: D000818:Animals; D001331:Automation; D049628:Body Size; D009068:Movement; D009835:Oligochaeta / Q000033:anatomy & histology* / Q000502:physiology; D013045:Species Specificity; D013997:Time Factors