THE NEOPTEROUS ORDERS PLECOPTERA (stoneflies)

Relative Abundance of the Major Insect Divisions From the phylogenetic tree: Endopterygota = Coleopteroids + Strepsiptera + Lepidopteroids + Dipteroids + Hymenoptera Exopterygota = Hemipteroids + Paleoptera + Orthopteroids Apterygota = Thysanura + Archaeognatha

HEMIMETABOLOUS HOLOMETABOLOUS ? Plecoptera Zoraptera Embiodea Dermaptera Grylloblattodea Mantophasmatodea Polyneoptera HEMIMETABOLOUS Phasmida Orthoptera Mantodea Isoptera Blattaria Psocoptera Neoptera Phthiraptera Paraneoptera Thysanoptera Hemiptera Coleoptera Rhaphidioptera Neuropterida Megaloptera Neuroptera Hymenoptera HOLOMETABOLOUS Mecoptera Siphonaptera Diptera ? Panorpida Strepsiptera Trichoptera Lepidoptera

Relationships of the Polyneoptera Plecoptera Zoraptera Plecopterida Embiodea Dermaptera Grylloblattodea Mantophasmatodea Phasmida Orthoptera Orthopterida Mantodea Isoptera Dictyoptera Blattaria

Main features of Polyneoptera 1. Chewing mouthparts

Main features of Polyneoptera 1. Chewing mouthparts 2. Nymph with ocelli

Main features of Polyneoptera 1. Chewing mouthparts 2. Nymph with ocelli 3. Numerous Malpighian tubules

Main features of Polyneoptera 1. Chewing mouthparts 2. Nymph with ocelli 3. Numerous Malpighian tubules 4. CNS with abdominal and thoracic ganglia

Embiodea(=Embioptera) Aquatic nymphs Ovipositor lost Plecoptera Terrestrial nymphs Silk glands Embiodea(=Embioptera) No silk glands Zoraptera Dermaptera prognathous head Cerci modified to forceps Cerci not modified Grylloblattodea ? Mantophasmatodea Saltatorial hind legs Orthoptera Hind legs not saltatorial Phasmatodea

Why aren’t stoneflies in the Paleoptera? Similar wing venation Similar nymphal forms

Why aren’t stoneflies in the Paleoptera? Wing folding Gill types & location

Stonefly wings

Classification of Plecoptera Order Suborder Superfamily Comment Plecoptera Anarctoperlaria -southern Hemisphere -very primitive Arctoperlaria Systellognatha -mandibles of adult atrophied Euholognatha -mandibles of adult normal Anarctoperlaria Systellognatha Euholognatha

Drumming

Drumming http://www.cas.unt.edu/~StoneflyHome/Contents/Chap_12/

General Evolutionary Trends Originated in cold flowing water Euholognatha -feed as adults -diurnal -herbivorous Systellognatha -warmer slower water -carnivorous (nymphs) -nocturnal

Ecological Classification of Plecoptera 1. Winter stoneflies 2. Summer stoneflies -emerge in warmer months -emerge in warmer months -nymphs are predaceous -nymphs are detritivores -adults are non-feeding -adults are algae or pollen feeders

Hexapod Orders Plecoptera Pleco - folded/pleated, ptera - wing Number of Species >2000 Common names Stoneflies, salmonflies Typical habitats fast-moving streams -temperate/boreal climates Distinguishing characteristics Adults - hind wings shorter; base of hind wing enlarged and pleated Nymphs - Body flattened, Tracheal gills behind the head, at base of legs, or around the anus, two ‘tails’ Other features Most primitive of Neoptera