Overview

Overview

Pecatonica River Mayfly (Acanthametropus Pecatonica), a State Endangered invertebrate, are known only from nymphal specimens. The mature nymph is about 0.8 inches (20 mm) long, creamy white with three short tail filaments densely fringed on the margins, a small head with lateral eyes, and abdominal segments one through seven each bearing a distinctive pair of plumelike gills. Paired spines of the head, thorax, and a row of dorsal abdominal spines distinguish this nymph. There is no information known about the adult mayfly and repeated attempts to rear Wisconsin nymphs to adulthood have been unsuccessful. The species habitat requirements include sand-bottom rivers with little water pollution. The specimens found in Wisconsin have been collected from large, sand-bottomed rivers with wide channels, in water a meter or less deep. Records from Illinois are from moderately sized, fast, shallow streams with sand and rock bottoms.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Pecatonica River Mayfly (Acanthametropus pecatonica). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication PUB-ER-085-99 (now out-of-print).

Identification: Known only from nymphal specimens. The mature nymph is about 0.8 inches (20 mm) long, creamy white with three short tail filaments densely fringed on the margins, a small head with lateral eyes, and abdominal segments one through seven each bearing a distinctive pair of plumelike gills. Paired spines of the head, thorax, and a row of dorsal abdominal spines distinguish this nymph. There is no information known about the adult mayfly and repeated attempts to rear Wisconsin nymphs to adulthood have been unsuccessful.

Habitat: Wisconsin specimens have been collected from large, sand-bottomed rivers with wide channels, in water a meter or less deep. Records from Illinois are from moderately sized, fast, shallow streams with sand and rock bottoms.

State Distribution: The species occurs in the Mississippi River and the Wisconsin River in Grant County, the Chippewa River in Pepin County, and the Black River in Trempealeau County.

Phenology: The Pecatonica River mayfly nymph is predaceous, the main food item thought to be Chironomids (midges). Specimens have been collected from May through early July. Presumable like other mayflies, the terrestrial adults are short-lived, nonfeeding, and spend time in reproductive activities: swarming, mating, and ovipositing.

Management Guidelines: Many species of mayflies are known to be highly susceptible to water pollution. Dredging, which slowed the rivers and created mud bottoms, undoubtedly hastened the demise of the Illinois populations of this species. Pecatonica River mayflies require sandy habitat. Activities protecting the integrity of large, clean, sand-bottom rivers will be beneficial to this mayfly.

Other resources

Links to additional Pecatonica River Mayfly information

Other links related to mayflies

• NatureServe Explorer
• The Field Museum [exit DNR]
• University of WI Extension - Water Action Volunteers [exit DNR]
• EPA Biological Criteria [exit DNR]
• University of MN - Aquatic Insect Interactive Verification Program [exit DNR]
• Volunteer Stream Monitoring Program: Guide to Aquatic Invertebrates of the Upper Midwest [exit DNR]

Photos/Video

Photos

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