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Plecoptera: Stoneflies “pleco” = folded

Plecoptera: Stoneflies “pleco” = folded. Pennsylvania. North America. World. Families. 9. 10. 15. Species. 132. 465. >2000. Number of Stonefly Species (from North American Stonefly List by Bill Stark http://www.mc.edu/campus/users/stark/Sfly0102.htm). Plecoptera: Stoneflies.

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Plecoptera: Stoneflies “pleco” = folded

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  1. Plecoptera: Stoneflies“pleco” = folded

  2. Pennsylvania North America World Families 9 10 15 Species 132 465 >2000 Number of Stonefly Species(from North American Stonefly List by Bill Stark http://www.mc.edu/campus/users/stark/Sfly0102.htm)

  3. Plecoptera: Stoneflies • Very sensitive indicators of clean, oxygenated waters • Important food source for game fish • Common Families • Perlidae-common stoneflies • Taeniopterygidae-winter stoneflies; emerge January to April • Nemouridae-spring stoneflies; emerge April to June • Most diverse in small, cool streams that do not exceed 25F and are nearly oxygen saturated • Strong preference for coarse substrates • Almost exclusively lotic • Some are shredder-detritivores; others are predators on midges, blackflies and mayflies

  4. Life History • Most have one generation/yr, but some require two years • Various species emerge in all months • Egg masses deposited on surface of water; breaks apart; eggs stick to bottom; hatch in 3-4 weeks • 10-11 months as larvae (range 6 months-3 years), molting 10-22 times • May respond to predators by playing dead; rejected by sculpins; one family autohemorrages • Prior to emergence they may enter drift community; leave water at night; molt in ~ 10 minutes • Move to vegetation to pass teneral stage; • Adults live 1-4 wks; mostly active at night • Sexes ‘drum’ to each other to locate mates

  5. Immatures Antennae long and filiform Body dorsoventrally flattened Ventral tracheal gills present around head, legs, or anus Thoracic segments covered by dorsal sclerite Two long, multisegmented cerci Two tarsal claws Adults Antennae long and filiform Two long, multisegmented cerci 2 prs of membranous wings with many veins Hind wings much wider than fore wings; thus hind wings are pleated to fit under the fore wings Plecoptera: StonefliesHemimetabolous: egg  nymph (naiad)  adult

  6. Nymph

  7. Adults

  8. The interesting case of Winter Stoneflies • Two families live this ‘backward’ life history • Eggs hatch in late winter • When water warms they migrate 1 m or more to the rocky hyporheic zone; enter diapause for 3-6 months • Cool water stimulates feeding & growth • Emerge in winter; • Dark colored; often on rocks; why?

  9. Ecological Role • As shredders, they break downleaves, twigs, etc. • Create greater surface area for colonization by bacteria, fungi, etc., as well as for other invertebrates • Important food for other organisms • Probably the most pollution sensitive order of aquatic insects

  10. http://www.cals.ncsu.edu/course/ent425/compendium/stonef~1.html#classhttp://www.cals.ncsu.edu/course/ent425/compendium/stonef~1.html#class

  11. Stoneflies of Pennsylvania

  12. Nymphs

  13. Adults

  14. Links • Plecoptera: http://www.cals.ncsu.edu/course/ent425/compendium/stonef~1.html#class

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