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:1. Float to surface, use exuvium as raft; better be quick!2. 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