Ephemeroptera: Mayflies

Ephemeroptera: Mayflies

In North America •17 families •680 species (569 in US) •PA species

Hemimetabolous

Egg

Larva/nymph/naiad

Adult

Larvae

http://www.cals.ncsu.edu/course/ent425/compendium/mayfly.html

More Larvae

Life History • •

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Usually one generation/yr, some have two; others may take 2 years/generation (tend to be larger species) Eggs always laid in water; hatch in 1 week to several months; diapause may last up to 11 months Larval stage lasts 3-6 mos (range 10 days-2 yrs); molt many times (more than any other aquatic insect: 12-27 times; 45x in some species); may vary even within species Emergence: 1. 2.

Float to surface, use exuvium as raft; better be quick! Crawl to edge (~5cm) to emerge

Life History continued • Have unique subimago life stage: the only flying insect that is not fully developed, i.e., sexually mature • Wings are dull and semitransparent due to fine hairs • Subimagos of same species and habitat usually synchronize emergence…why? • Subimago lasts ~ 24 hrs (range: minutes to 2 days) • Adult is imago-has shiny wings

Subimago (aka dun)

Adult or Imago (aka spinner)

Reproduction • Adult lives 24 hrs (range: 90 minutes to 2 days); don’t feed-have no mouth parts and degenerate digestive systems • Males-only swarm over water; have distinctive swarming behavior • Lay eggs and die; some explode!

Significance & Ecological Role • Mass emergences may be annoying (Put-in-Bay snowplows; Port Clinton brownout) • Most are sensitive to pollution, hence are clean water indicators • Feed mostly on algae, plant material, detritus • Are the mice and rabbits of the aquatic ecosystem: convert much of the plant matter into animal flesh • An essential link in the food chain

Adults

Trout must be really dumb