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PLECOPTERA -- <Images> & <Juveniles> [Latest Classification] Please refer also to the following website for details on this
group: Stone flies inhabit pure and well-aerated
waters and thus are found only in streams, brooks and on lake shores. The nymphs of most species feed on aquatic
vegetation, and only in the Perlidae, especially the genera Acroneuria and Perla, are they essentially carnivorous (Clausen 1940/1962). Some apterous species are entirely aquatic
throughout their life. In this family the mouth parts of nymphs are
definitely modified for predation.
Frison (1935) noted predaceous species as probably occurring in Perlidae,
Perlodidae and Chloroperlidae. The
latter family shows a wide range of food habits (Clausen 1940/1962).
The name means "braided-wings", derived from the Greek plekein
to braid" and pteryx "wing". This refers to the complex
venation of their two pairs of wings, which are membranous and are held
folded over their back. They are not
strong fliers, and some species are apterous. There are over
3,510 described species with worldwide distribution except for Antarctica. They are regarded
as very primitive Neoptera, with
ancestral groups being known the Carboniferous and Lower Permian periods. Plecoptera are
good indicators of water pollution and their presence is indicative of good
water quality.
Their appearance is generalized with some specialized
characteristics. The simple
mouthparts have chewing mandibles.
The antennae are long with many segments. There are large compound eyes and 2-3 ocelli. The legs are
strong, each ending in two claws. The abdomen is soft, and adults may bear
remnants of the nymphal. Both nymphs
and adults have long paired cerci that extend out from the back of the
abdomen.
Females may lay hundreds thousands of eggs in a clump that carry on their
abdomen, and later deposit into the water.
Hatching is in about 2-3 weeks, but some species enter diapause in dry
seasons. The nymphs may persist for 1-4 years,
after which they undergo may molt 12-33 times before adulthood.. The adults
are terrestrial and usually only live for a few weeks, and emerge only during
certain times of the year. Some adults feed as herbivores or not at all. The aquatic nymphs inhabit the
benthic of highly oxygenated lakes and streams. However, terrestrial nymphs
are also known but only in relatively moist habitats. The nymphs appear as
wingless adults, but often have external gills. Respiration may also occur through the body surface, and some
species do not possess gills at all.
Most numphs are herbivorous, feeding on submerged leaves and benthic
algae, but some are predators of other aquatic biota. = = = = = = = = = References: Please refer to <biology.ref.htm>, [Additional references
may be found at: MELVYL
Library] Holst, E. M.
2000. Lake Tahoe benthic stonefly (Capnia lacustra). In: Murhy, D.D. &
Knopp, C.M.: Lake Tahoe Watershed Assessment: O-118 –
O-120. USDA. PDF fulltext Hynes, H. B.
N. 1993. Adults and Nymphs of British Stoneflies. Freshwater
Biological Association. ISBN 0-900386-28-2 Nelson, C. R.
1996a. Tree of Life Web Project - Capniidae. Winter
Stoneflies. Version of 1996-JAN-01. Retrieved 2008-JUL-31. Nelson, C.
R 1996b Tree of Life Web Project - Plecoptera. Stoneflies. Version of
1996-JAN-01. Retrieved 2008-JUL-31. Zwick, P.
2000. Phylogenetic System and Zoogeography of the Plecoptera. Annu. Rev. Entomol. 45: 709-746. 2008.
Fochetti, R. & De Figueroa. 2008. Global
Diversity of Stonflies (Plecoptera; Insecta) in Freshwater. Hydrobiologia
595: 265-377. |