Hydrotaxis(redirected from hydrotactic)
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the movement of free-moving unicellular and colonial plants and some animals to greater moisture (positive hydrotaxis) or less moisture (negative hydrotaxis). Hydrotaxis, like other taxes, is determined by the needs of the organism. For example, larvae of some insect species (wireworms, for example) move to deeper, more moist layers of the soil when the top layers dry out.