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.
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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.