Conocephalus, Thunberg, 1815

Piotr Naskrecki, 2000, Katydids of Costa Rica / Vol. 1, Systematics and bioacoustics of the cone-head katydids (Orthoptera: Tettigoniidae: Conocephalinae sensu lato)., Philadelphia, PA: The Orthopterists Society at the Academy of Natural Sciences of Philadelphia, : 13-14

CONOCEPHALUS Thunberg, 1815

Common Name: Meadow katydids

1815 Thunberg, Mem. Acad. St. Petersb. 5: 214; type species: Gryllus Tettigonia conocephalus Linnaeus, 1767

1999 Naskrecki and Otte, Illustr. Cat. Orthop. I (CD ROM) >>references; types illustrated

[syn.] Xyphidium = 1853 Fieber, Lotos 3: 170; type species: unknown

[syn.] Palotta = 1869 Walker, Cat. Derm. Salt. Brit. Mus. 2: 249; type species: Palotta inornata Walker [syn. of Conocephalus iris (Serville) ], by monotypy

[syn.] Xiphidium = 1838 Burmeister, Handb. Ent. 2: 707 >>Replacement name for Xiphidion Serville 1831 .

Diagnosis

Body slender, small as for the family; macropterous, mesopterous, brachypterous or squamipterous ( Figs. 1 A, 2A, 36A, 37D); tegumen smooth. Fastigium of vertex laterally compressed, rounded apically, never cone-shaped; no traces of genal carinae present; mandibles and labrum symmetrical; eyes relatively large. Pronotum short, lateral lobes approximately triangular, posterior edge of lobe with “secondary tympanum.” Stridulatory file with peg like teeth. All legs slender, fore and mid femora unarmed on lower margins. Male cercus usually armed with one internal tooth, rarely unarmed; ovipositor straight to weakly curved, with upper and lower margins parallel.

Description (male except where specified)

Head.— Fastigium of vertex 0.75 to 1.5 times as wide as scapus ( Figs. 1 C-E), laterally compressed, rounded dorsally and apically, never hook- or cone-shaped, never projecting strongly in front of eyes; fastigium of vertex touching fastigium of frons. Eyes large relative to size of head, weakly protruding. Frons weakly convex, smooth; tegumen of head smooth, without traces of genal carinae; face slender. Mandibles and labrum symmetrical.

Thorax and wings.— Dorsal surface of pronotum smooth, flat or metazona slightly raised; anterior dorsal margin straight, posterior one straight or weakly convex; lateral lobes approximately triangular, with acute posterior angle; posterior edge of lateral lobe with “secondary tympanum” – a somewhat raised, narrowly elliptical area of thinner cuticle covering thoracic auditory spiracle; humeral sinus poorly developed or absent ( Fig. 1 A). Thoracic auditory spiracle large, elliptical, completely hidden under lateral lobe of pronotum; posterior edge of spiracle unmodified. Prosternum unarmed or armed with two thin, short spines (modified basisternum); meso- and metasternum with lateral lobes of basisterna small, triangular, their inner margins touching; posterior part of metasternum strongly compressed causing hind coxa to nearly touch each other.

Wings in both sexes either fully developed, well surpassing apices of hind femora , with hind wings usually distinctly longer than tegmina; or wings shortened, barely reaching apex of abdomen; or wings shortened not reaching apex of abdomen; or wings very short, not reaching middle of abdomen, squamipterous in females; often intermediate forms occur, and many species have both macro- and brachypterous forms; in macropterous forms tegmina slender, narrowly rounded apically ( Fig. 2 A). Stridulatory apparatus of male well developed; stridulatory area of left wing membranous, without a network of secondary veinlets; stridulatory file (vein AA 1 —new vein homology after Kukalova-Peck, personal communication; male stridulatory file used to be homologized with the vein Cu 2) sinusoidal ( Figs. 1 B-F), teeth thick, peglike, sparsely arranged, especially on distal end of file; mirror of right wing approximately rectangular, with secondary veinlet next to AA 1 always well developed, divergent from AA

1

.

Legs.— All legs long and slender; fore coxa with an elongate, forward projecting spine dorsally. All femora unarmed dorsally; fore and mid femora unarmed ventrally, hind femora armed ventrally with relatively few minute spines or unarmed; genicular lobes of femora usually armed with short spines, sometimes only inner genicular lobes armed. Fore and mid tibiae unarmed dorsally, both ventral margins with immovable spines as long as 1/4 to 1/2 diameter of tibia; hind tibia armed on all four dorsal and ventral margins; apex of tibia with two pairs of ventral and one pair of dorsal movable spurs. Tympanum on fore tibia bilaterally closed, tympanal slits facing forward, tympanal area weakly to distinctly swollen, with pair of small, elongated pits below tympanal slits.

Abdomen.— Dorsal surface of abdominal terga smooth, unmodified. Male 10th tergite usually strongly sclerotized, with narrow apical incision, supraanal plate small, triangular. Male cercus variable but usually with one internal spine, sometimes unarmed or with apex of cercus modified into spine ( Figs. 39 A-H); female cercus, simple, slender and weakly incurved. Subgenital plate of male with a pair of styli, distinct median keel, truncated apically or with triangular apical emargination; female subgenital plate approximately triangular, rounded or shallowly emarginated apically. Concealed genitalia of male with paired, heavily sclerotized, hook-like titillators ( Figs.2 G-K). Ovipositor narrow, straight to weakly curved; its length variable, from distinctly shorter to over twice as long as hind femur; both dorsal and ventral margins of ovipositor smooth, parallel; apex of upper valvula sharp ( Figs.2 B-F).

Coloration.— General coloration usually green, sometimes straw brown, almost invariably with dark, wide stripe on head and pronotum (stripe black and extending along the dorsal side of the abdomen in nymphs of probably all species); abdomen usually green but often apical half of abdomen colored differently, yellow, orange, red or purple (especially in males); sometimes dorsal side of abdomen yellow, with dark, longitudinal stripes. Tegmina straw brown to light green; legs green to light brown.

Remarks.— The genus Conocephalus , with its 7 subgenera, is the largest genus of the Tettigoniidae , having at least 161 valid species, distributed on all continents. Most species of the genus are associated with open, grassy habitats. Both nocturnal and diurnal species are known, and both can occur within the same habitat. They are known to be herbivorous, omnivorous, or predominantly predaceous, and some can be of significant economic importance. Two species from New Guinea, C.

redtenbacheri (Bolivar) or C. semivittatus vittatus (Fabricius) , have potential as biocontrol agents, being wellknown predators of rice pests ( Pitkin 1980). In Cuba, C. fasciatus (De Geer) and C. brevipennis (Scudder) were observed feeding on caterpillars of Mocis sp. ( Lepidoptera , Noctuidae ) (De Zayas 1974). The only Costa Rican species of the genus known be beneficial is C. saltator , which is reported as a predator of pests in the sugar cane fields of the Hawaiian Islands ( Zimmerman 1948). On the other hand, it can cause damage to rice ( Grist and Lever 1969) as well as corn and pineapple ( Zimmerman 1948). In the last case, the damage is caused by laying its eggs in the flowers of the plants rather than by feeding on them. Another species known from Costa Rica, C. cinereus , was listed as a pest of rice in Guyana and Surinam ( Grist and Lever 1969). It has also been reported as injurious to tobacco seedlings in San Lorenzo, Puerto Rico (Wolcott 1950, in Gurney 1959). Gurney (1959) also reports that specimens of this species have been seen feeding on the banded cucumber beetle, Diabrotica balteata LeConte.

Costa Rican fauna of Conocephalus spp. is rather poorly known and requires additional, extensive collecting and studying. At least 5 species occur in this country, including 1 species new to science, described below. With the exception of C. angustifrons , all Costa Rican species seem to be chiefly diurnal. Conocephalus angustifrons is predominantly predaceous and individuals of this species have been observed capturing insects of the size equal to their own, including adult individuals of the predaceous katydid Phlugis sp. Little is known about the diet of the remaining species but they seem to feed on seeds and leaves of various grasses. Males of most species of Conocephalus produce continuous, high duty calls, which can be heard during the day in nearly all open, grassy areas of the country.

Figures

FIG. 1. Costa Rican Conocephalus spp. A. C. saltator - habitus; B-F: male pronotum, dorsal view. B. C. saltator, C. C. angustifrons, D. C. ictus, E. C. cinereus, F. C. magdalenae.

FIG. 2. Costa Rican Conocephalus spp. A. C. cinereus - habitus; B-F: ovipositors. B. C. magdalenae, C. C. cinereus, D. C. ictus, E. C. angustifrons, F. C. saltator; G-K: titillators. G. C. magdalenae, H. C. cinereus, I. C. ictus, J. C. angustifrons, K. C. saltator

FIG. 39. Cerci and stridulatory files of species of Conocephalus. A-H. male left cerci, dorsal views: A. C. saltator, B. C. angustifrons, C. C. magdalenae, D. C. fasciatus, E. C. ictus, F. C. cinereus, G. C. spinosus, H. C. cf. spinosus; I-J. male stridulatory files: I. C. saltator, J. C. angustifrons.