Department of Entomology

Ephemeroptera (Mayflies)

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Ephemeroptera - Brigham Young/VPI & SU PCD0350004

I. Background Information

A. Origin of name

1. ephemero, for a day, short-lived; ptera, wings

B. Classification

Families and species in North America north of Mexico - 17 families, 619 species

C. Common names - mayflies; also willowflies, shadflies, Canadian soldiers

D. Type of metamorphosis - simple (hemimetabolous)

E. Phylogenetic relationships - paleopterous exopterygota

II. Morphological Characteristics

A. Two-pair of triangular, membranous wings with many veins

B. Ten-segmented abdomen with two to three caudal filaments (cerci)

C. Fragile-looking

III. Biological Summary for Order

A. Life history

1. Eggs - usually several hundred to 1000; always in water; usually hatch in several days
2. Immature stages - nymphs; usually 3 to 6 months (ranges from 3 weeks to 2 years); up to 45 instars (more than any other insects)
3. Subimago - only insect to molt after developing functional wings; wings have dull appearance; usually 24 to 48 hours (can be as short as 2 minutes)
4. Adults - only live for 2 to 3 days (some as short as 90 minutes); sole purpose is mating
5. Number of generations per year - usually univoltine or bivoltine (some multivoltine, some semivoltine)
6. Time of emergence - most in spring; some in summer and continuing into fall
7. Delays in development - some diapause for 3 to 9 months as eggs in warm months (some up to 11 months)

B. Habitat and habits

1. Adults - do not disperse very far from aquatic habitat
2. Nymphs - common in flowing and standing waters; in flowing waters, greatest diversity is found in ver fast rocky riffles, where nymphs ching to rocks or swim in short bursts; in standing waters, greatest diversity is found in areas of vegetation or accumulations of plant debris, where nymphs climb about

C. Food

1. Adults - do not feed
2. Nymphs - eat plant material, either live algae, or fine particlyes of detritus

D. Respiration

1. closed tracheal system with gills on abdomen

E. Collecting and Preserving Adults

Best collected by aerial netting while swarming and sweep netting in vegetation near water; specialists collect mature nymphs and rear to adults; some species are attracted to lights; preserve in 70% ethanol

F. Behavior

1. Adults - use swarms to locate mates; males congregate in swarms, which have species specific patterns

G. Significance

1. Economic - No adverse economic significance (like all aquatic insects, except some Diptera). Some beneficial economic significance in angling (flies of trout fishermen).
2. Ecological - Part of food web and used for pollution assessment

Prepared by: J. R. Voshell, VPI & SU
Last modified: 9/3/96