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General Entomology EEB 286 University of Connecticut Fall 2006 Orthoptera Page 1 ORTHOPTERA NAME ORIGIN: Gk. orthos – straight; pteron – a wing. INTRODUCTION: Crickets, grasshoppers, and katydids. The largest non-hemipteroid or exopterygote insect lineage, with over 21,000 species worldwide. There are about 3,000 species documented from the US and Canada with perhaps 25% of the total undocumented. Some orthopteran species cause enormous economic damage (e.g. introduced mole crickets in Florida cause ca. $44 million dollars damage yearly). Orthopteran consumption of plant biomass (primarily grasses) may exceed mammalian and lepidopteran. RECOGNITION: • usually 2 pairs of wings with first pair often thickened (referred to as tegmen; pl. tegmina) • antennae many-segmented • cerci present • hind femora often enlarged (for jumping) HABITATS: Most orthopterans are herbivorous (some are predaceous and omnivorous) and are thus found among vegetation. Some species are nocturnal. A few are arboreal. COLLECTING: Many orthopterans are collected by sweeping through vegetation. For complete species lists, night collecting is required and the use of songs to identify, or at least find, orthopterans is quite advantageous. TAXONOMY: Two groups are recognized: those with short antennae and short ovipositors (Caelifera) and those with long antennae and ovipositors (Ensifera). The Caelifera includes the grasshoppers and related lineages. The Ensifera includes the Tettigoniidae (katydids and others), the Gryllacrididae (Jerusalem crickets and others), and the Gryllidae (common field cricket, Gryllus, and others). Suborder: Caelifera Family Tetrigidae: pygmy grasshoppers or grouse locusts • pronotum extending backward over the abdomen becoming narrow posteriorly • 13 to 19 mm in length • adults most often encountered in spring and early summer (on mud around water courses) • do not produce sound and lack hearing organs (tympana) Family Acrididae: grasshoppers and locusts • • • • • antennae nearly always relatively short tarsi with three or fewer segments tympana (hearing organs) located on sides of first abdominal segment species that stridulate usually do so by rubbing hind femora over tegmina or abdomen or snapping wings in flight short cerci and ovipositor General Entomology EEB 286 University of Connecticut Fall 2006 Orthoptera Page 2 Suborder: Ensifera Family Tettigoniidae: long-horned grasshoppers and katydids • • • • • long hairlike antennae four-segmented tarsi auditory organ located at base of front tibia laterally flattened, blade-like ovipositor most species with well-developed stridulating organs on front wing bases – they are noted songsters Each species has a characteristic song. The winter is usually passed in the egg stage, and in many species the eggs are inserted into plant tissues. Most species phytophagous, but a few prey on other insects. Family Gryllacrididae: wingless long-horned grasshoppers • • • • rust, tan, or brown humpbacked in appearance found in caves, hollow trees, under logs and stones, and in other dark moist places antennae and other appendages often very long Family Gryllidae: crickets • • • • • • tapering antennae stridulating organs on front wings of male auditory organ on front tibia not more than three tarsal segments ovipositor usually needle-like or cylindrical rather than flattened front wings bent down rather sharply at sides of body
