ARTHROPOD MUSEUM NOTES
Number 25 • October 16, 2003 • Jeffrey K. Barnes
Common meadow katydid
Genus and species: Orchelimum vulgare Harris
The genus Orchelimum includes 21 meadow katydid species, all of them restricted to North America. Only 5 species are likely to be found in Arkansas. Orchelimum vulgare frequents dry, weedy fields, gardens, and lawns. Orchelimum sylvaticum McNeill is an arboreal species. Orchelimum nigripes Scudder, O. campestre Blatchley, and O. carinatum Walker prefer wetlands, the latter perhaps restricted to habitats bordering the Mississippi River (Morris and Walker 1976).
Orchelimum vulgare is widespread in eastern North America, occurring from Maine and southern Quebec west to North Dakota and southern Manitoba, and south to Georgia, Louisiana, and eastern Texas. It is the most common meadow katydid in Arkansas. Its color is variable and includes light shades of green and brown. A conspicuous brown stripe runs down the midline of the pronotum. The eyes are orange. Males are territorial and tend not to leap away when disturbed. Rather, they move to the side of their perch that is opposite the source of disturbance.
The common meadow katydid is univoltine. It passes the winter in the egg stage in plant tissue, and nymphs emerge in May and June. The nymphs feed readily on clover and other forage crops, but apparently adults feed mostly on aphids and other insects, with some plant material making up part of their diet. Adults begin to appear in late July, and eggs are laid in September and October (Forbes 1905, Metcalf and Colby 1930).
An ovipositing female embraces a plant stem with her prothoracic and mesothoracic legs and brings the curved and sword-like ovipositor far forward so its tip can scrape the substrate. The female applies great pressure while swaying her body back and forth. The ovipositor slowly sinks into the plant tissue and becomes buried to its base. Although it enters the twig at a right angle, it is directed backward as it sinks into the tissue. An egg is then deposited and the ovipositor is withdrawn. The female turns around and splinters the surface of the twig over the puncture with her mandibles. The ovipositor is then sunk through the same puncture, but in the opposite direction, and another egg is deposited. The process of laying eggs alternately up and down the twig, with each deposition followed by splintering of wood above the puncture, can sometimes continue until 10 or 12 eggs are laid around a single puncture, with 4 or 5 abreast on each side of the puncture (Metcalf and Colby 1930).
As with other species of Orchelimum, the calling songs of the common meadow katydid are produced only by males. Males sing both day and night. The songs are apparently intended to attract females and to maintain local territory free of other males. Males will interact aggressively with other males singing in their territory. Silent intruders are ignored. The fighting takes the form of brief venter-to-venter grappling, and it usually ends with silent withdrawal of the subordinate male, while the victor sings from his perch (Morris 1971, 1972). Sound is produced using stridulating structures on the bases of the leathery forewings, which are known as tegmina. During stridulation, the tegmina remain flexed over the abdomen, but they are alternately raised and lowered. As the tegmina are pulsed, the upturned rim of the scraper on the right tegmen engages with a row of teeth on the file located on the lower surface of the left tegmen. The resulting vibration of the wing produces the song. The song has a two-part structure with a series of trills or buzzes interspersed with staccato ticks. Each tick is double, consisting of two distinct pulse trains (Morris and Walker 1976).
Females have been known to lay eggs in the stems of a number of plant species. Oviposition activity has been known to damage sorghum in Arkansas and raspberry canes in Illinois (Riley 1893, Metcalf and Colby 1930).
Forbes, S. A. 1905. A monograph of insect injuries to Indian corn. Report of the State Entomologist of Illinois 23: 144-146.
Morris, G. K. 1971. Aggression in male conocephaline grasshoppers (Tettigoniidae). Animal Behaviour 19: 132-137.
Morris, G. K. 1972. Phonotaxis of male meadow grasshoppers (Orthoptera: Tettigoniidae). Journal of the New York Entomological Society 80: 5-6.
Morris, G. K., and T. J. Walker. 1976. Calling songs of Orchelimum meadow katydids (Tettigoniidae). I. Mechanism, terminology, and geographic distribution. Canadian Entomologist 108 (8): 785-800.
Metcalf C. L., and A. S. Colby. 1930. The meadow grasshopper Orchelimum vulgare Harris, a new raspberry pest. Journal of Economic Entomology 23: 97-108.
Riley, C. V. 1893. Notes from correspondents. Insect Life 5: 204.