Campsurus violaceus is a benthic species that play an important role in sediment bioturbation processes. We explored aspects of its basic biology and life-cycle in a subtropical lake (Laguna del Sauce, Uruguay). We elucidated the habitat preference of C. violaceus and evaluated if might foster a more diverse and abundant macroinvertebrate community. The population of C. violaceus showed univoltine behavior with nymphs all year around. The spatial distribution of Campsurus in the system was related with various sediment attributes, particularly granulometry. A clear positive relationship between abundance of C. violaceus and the associated macroinvertebrate community was found. This association could not be explained by the availability of basal resources, nor sediment preferences, but direct or indirect biotic interactions appeared to be important