Macroinvertebrates Occurring in Sunbeam Hot Springs, an Absolutely Hot Spring in Idaho, USA

ABSTRACT

On five occasions from 2000 to 2002, we sampled the macroinvertebrate fauna of the Sunbeam Hot Springs in central Idaho, USA. Spring surface water temperatures ranged from 52 to 58°C, and a relatively depauperate community was found, which comprised Coleoptera, Diptera, Hydracarina, and Ostracoda. The community varied little among the sampling dates, with total animal density of 86–168 ind./m² and total richness of seven taxa. The fauna of the Sunbeam Hot Springs resembles the fauna reported from hot springs in Washington, Alberta, and British Columbia more that the fauna from hot springs of Yellowstone National Park. The aquatic beetle Hydroscapha natans, a southern species not common to either the Pacific Northwest or Yellowstone, was collected in this Idaho hot spring.