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 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: 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