Crickets

Gryllidae. Spanish: Grillos (General). Portuguese: Grilos (Brazil).

Although many orthopteroids produce highly audible and complex sounds, it is the crickets that are best known for their musical talents. Males can make a variety of notes, most characteristically, a series of short, pulsed chirps or continuous soft trilling, more melodious and less rasping than the calls of katydids. The sound is produced by the vibration of membranous areas of the fore wings. These are set into motion when the scraper near the base of one wing is drawn across the opposing file of the other.

This acoustic behavior plays a major role in pair formation. Generally, the male gives a species-specific calling song to which females respond by approaching him. Males of ground-dwelling types call with the wings raised at about a 40-degree angle to the long body axis; those inhabiting vegetation hold their fore wings up at a right angle to the body axis. These positions are related to sound-producing efficiency in their habitats (Forrest 1982).

The Central American long-legged Am-phiacusta maya, found during the day in hollow trees and under overhanging banks, mates in groups consisting of both sexes and subadult nymphs. Male courtship chirping appears to be more of a warning to other males than a signal to females, to reduce fighting that reduces successful mating frequency (Boake 1984). The habits of related species, such as A. annulipes (fig. 5.4a), are mostly known. There is evidence that crickets also respond with evasive behavior to the ultrasonic emanations of bats, one of their chief predators (Doherty and Hoy 1985).

Crickets may be flattened or cylindrical in cross section. Most are small to medium-sized (BL 5-25 mm) but often have very much enlarged, muscled hind femora, making them good jumpers. The number of tarsal segments in the legs is reduced to three, not five like most other orthopteroids. The female's ovipositor is tubular and the cerci frequently large and conspicuous.

There are three major cricket types: (1) "bush crickets," which are small to medium-sized, brownish, and arboreal (several sub

Figure 5.4 CRICKETS, (a) Long-legged cricket (Amphiacusta annulipes, Gryllidae). (b) Bush cricket (Eneoptera surinamensis, Gryllidae). (c) Tree cricket (Oecanthus sp., Gryllidae), male, (d) Ground cricket (Gryllus sp., Gryllidae). (e) Mole cricket (Scapteriscus sp., Gryllotalpidae).

families; a widespread species is Eneoptera surinamensis; fig. 5.4b); (2) "tree crickets" (Oecanthinae, especially Oecanthus, fig. 5.4c, and Neoxabea), which are also found in vegetation but are delicate, pale green, and translucent, with slender bodies and legs and almost horizontal heads, males having broad, oval wings and thoracic glands that produce a mating pheromone (Walker 1967); (3) "ground and field crickets" (Gryllinae and other subfamilies), which are small to large and robust and generally live on the ground.

Among the last group are some species of native Gryllus, many going under the aggregate name G. assimilis (fig. 5.4d) (Aguilar and Saenz 1970). The related European house cricket (Acheta domesticus) has been introduced into Latin American houses from Europe but is not generally common. Already widespread and increasing its range rapidly is the Indian house cricket (Grylloides supplicans).

Probably because of their familiarity and the pleasant sounds emitted by the domestic species, numerous superstitions and folk beliefs have built up around crickets. They are almost universally considered a sign of good luck, although sometimes a harbinger of death. In Cara-guatatuba, Brazil, a black crickeL in a room is a signal of sickness, a gray one a sign of money, and green, of hope. In Rio Grande do Sul, Brazil, killing a cricket is thought to bring rain (Lenko and Papavero 1979).

In contrast to these mostly positive ways of viewing crickets, the leanings of these insects toward population explosions and their taste for crops stands them in poor stead with the farmer. Nocturnal and attracted by light and food, plagues of millions may invade fields and nearby urban areas, consuming leaves and covering everything, even piling up in drifts many centimeters deep in protected places.

The habits of native crickets are not well known among the poorly studied Latin American fauna. Crickets are generally herbivorous on grasses, herbs, and other plants but take insect prey opportunistically. Young tree crickets may be entirely predaceous on scale insects, aphids, and other small insects and thus may be of considerable benefit as natural control of these pests.

The family is large, although only some 500 species are now listed for Latin America (Chopard 1967—68); many species are awaiting description. As a group, they are widely distributed and are found in almost all life zones.

References

Aguilar, P. G., and D. Saenz. 1970. Algunas variaciones morfológicas en el grillo común de la costa central. Rev. Peruana Entomol. 13: 76-86.

Boake, C. R. B. 1984. Natural history and acoustic behavior of a gregarious cricket. Behaviour 89: 241-250. Chopard, L. 1967-68. Gryllides. In M. Beier, ed., Orthopterorum catalogus. W. Junk, Gravenhage.

Doherty, J., and R. Hoy. 1985. The acoustic behavior of crickets: Some views of genetic coupling, song recognition, and predator detection. Quart. Rev. Biol. 60: 457-472.

Forrest, T. G. 1982. Acoustic communication and baffling behaviors of crickets. Fla. Entomol. 65: 33—44.

Lenko, K., and N. Papavero. 1979. lnsetos no folclore. Sec. Cult. Cien. Tech, Sao Paulo.

Walker T.J. 1967. Revision of the Oecanthinae (Gryllidae: Orthoptera) of America south of the United States. Entomol. Soc. Amer. Ann. 60:784-796.

Mole Crickets

Orthoptera, Gryllotalpidae, Scapteriscus and Neocurtilla. Spanish: Grillotopos (General), changas (Puerto Rico), perritos de monte, playacuros (Peru). Portuguese: Grilos toupeiros, frades, macacos, cachorrinhos, daguas, paquinhas (Brazil). Ground puppies.

Mole crickets (fig. 5.4e), as their name implies, live in subterranean galleries. They are aptly specialized for digging by the modified forelegs, which are powerful excavating tools. The segments are massive and powerfully muscled and bear heavy spines on the under margin to form cutting chisels and scrapers. Other identifying features of these insects are their cricketlike form, fairly large size (BL 3—4 cm), medium brown color, and abbreviated fore wings beyond the tips of which the twisted hind wings project for some distance. Also, the entire surface of the body is covered with a short, sparse, yellowish velvet.

Female mole crickets deposit their eggs in a cluster in the enlarged chamber at the end of a side gallery. The nymphs remain underground, feeding directly on herbaceous plant roots or on stems of plants that they pull down into their underground passages. The adults feed in the same way but may also leave the burrow at night to disperse and find mates. They are fre quently attracted to artificial lights. Their food most often consists of seedlings or small crops growing in the friable soil they prefer for their diggings. Some species take considerable animal matter as food as well and should be considered omnivores (Castner and Fowler 1984a).

Although superficially similar, many distinct species in various genera (especially Scapteriscus) occur in Latin America with varied life-styles (Fowler and de Vasconcelos 1989). The best-known mole cricket, because of its taste for commercial plantings, is the changa of Puerto Rico (Barrett 1902, Thomas 1928). Formerly thought to be one species, Scapteriscus "vicinus," (actually didactylus but misidentified by all early authors), it may be comprised of two or more as indicated by the existence of populations with divergent mating songs; one was named S. imitatus (Nickle and Castner 1984). These and S. abbreviatus have been introduced to Puerto Rico from South America (Castner and Fowler 19846) and have become pests of turf and agriculture. Scapteriscus oxydactylus is the largest South American mole cricket and is a pest of rice and other crops cultivated along the banks of the Amazon River when the waters are receding. Some natural control is wrought by the cricket's parasitoid enemies in the sphecid wasp genus Larra (Castner 1984, Castner and Fowler 19846).

Male mole crickets use songs to call mates (Forrest 1983). The sound is a broken trill at a pulse rate of about 57 to 68 per second and of low frequency. It is emitted by the insect underground, either from closed burrows or through special funnel-shaped openings to augment the sound ("acoustic horns") (Bennet-Clark 1970). Females occasionally also make sounds of short duration and for unknown purposes (Ulagaraj 1976). Stridulation is accomplished by friction between scraper and file elements on the fore wings, much like true crickets (Bennet-Clark 1970).

References

Barrett- O. W. 1902. The changa, or mole cricket (Scapleriscus didaclylus Latr). Puerto Rico Agric. Exper. Sta. Bull. 2: 1-19.

Bennet-Clark, H. C. 1970. The mechanism and efficiency of sound production in mole crickets. J. Exper. Biol. 52: 619-652.

Castner, J- L. 1984. Suitability of Scapleriscus spp. mole crickets [Ort.: Gryllotalpidae] as hosts of Larra bicolor [Hym.: Sphecidae]. Entomophaga 29: 323-329.

Castner, J- L., and H. G. Fowler 1984ö. Gut content analysis of Puerto Rican mole crickets (Orthoptera: Gryllotalpidae: Scapleriscus). Fla. Entomol. 67: 479-481.

Castner, J- L., and H. G. Fowler 19846. Distribution of mole crickets (Orthoptera: Gryllotalpidae: Scapleriscus) and the mole cricket parasitoid Larra bicolor (Hymenop-tera: Sphecidae) in Puerto Rico. Fla. Entomol. 67:481-484.

Forrest, T. G. 1983. Phonotaxis and calling in Puerto Rican mole crickets. (Orthoptera: Gryllotalpidae). Entomol. Soc. Amer. Ann. 76: 797-799.

Fowler, H. G., and H. L. df. Vasconcelos. 1989. Preliminary data on life cycles of some mole crickets (Orthoptera, Gryllotalpidae) of the Amazon Basin. Rev. Brasil. Entomol. 33: 134-141.

Nickle, D. A., and J. L. Castner 1984. Introduced species of mole crickets in the United States, Puerto Rico, and the Virgin Islands (Orthoptera: Gryllotalpidae). Entomol. Soc. Amer. Ann. 77: 450-465.

Thomas, W. A. 1928. The Puerto Rican mole cricket. U.S. Dept. Agr., Farm. Bull. 1561: 1-8.

Ulagaraj, S. M. 1976. Sound production in mole crickets (Orthoptera: Gryllotalpidae: Scapleriscus). Entomol. Soc. Amer. Ann. 69: 299-306.

Short-Horned Orthopteroids

Orthoptera (= Caelifera)

Grasshoppers make up the majority of this group, which is characterized by short antennae with less than thirty segments. Auditory organs, when present, are located on the tergum of the first abdominal segment. Stridulatory structures are on the distal portions of the wings.

grasshoppers

Acrididae. Spanish: Saltamontes, saltarines, saltones (General); tucuras (Argentina). Nahuatl: Chapultins, sing, chapolin (Mexico). Quechua: Chili cutu. Portuguese: Gafanhotos.

Grasshoppers are so familiar that they hardly need description. The characteristics of enlarged hind femur (containing the jumping muscles) combined with short, stout antennae always distinguish them from similar orthopteroids. The dorsal part of the prothorax forms a broad collar, folding over the segment on the sides, and is often crested middorsally. Both sexes also possess an auditory organ, visible as a circular membrane, on either side of the basal abdominal segment. Most have fully developed wings, the fore wing being elongate and parallel sided, the hind wing broad, fanlike, and reticulate veined. Many types have reduced or virtually no wings and are flightless, particularly some high Andean (Melanoplus; Roberts 1973) and rain forest (Rowell 1978) types.

The female uses her short ovipositor to excavate holes in the soil into which she deposits up to one hundred elongate eggs in a mass cemented together with a viscid secretion. Both nymphs and adults feed on vegetation and when abundant, are devastating crop pests. Certain species, especially in the genus Schistocerca, form enormous migrating swarms that can destroy fields over wide areas. These are the locusts, most famous in the Old World but represented by a species in Latin America no less imposing or devastating.

Although grasshoppers have been used as sustenance by peoples in Africa, the Middle East, and other parts of the world, both in history and today, they seem to be of relatively minor importance as a food in tropical America. Exceptions in the past were the natives of several West Indian islands who, as Martyr (Bodenheimer

1951: 301) records, ate grasshoppers and stored them for trade. Padre Florian Pauche, who lived with the Mocovies Indians of Argentina in the eighteenth century, described their practice of catching, cooking, and eating the locusts (Schistocerca) that periodically plagued their land (Lie-bermann 1948).

Grasshoppers were important in the diet of the Aztecs; one species was called acahapali, arrow, in Nahuatl, because of its shape and because it made a distinctive buzz in flight (Curran 1937). According to Kevan (1977), the word chapulli apparently referred to many edible species, particularly Sphenarium, and formed the basis for many place-names in central Mexico during the period of the Aztec civilization. A hill in Mexico City, famous to the Aztecs and where Maximilian's castle is located, was named chapultepec, combining the word for grasshopper with hill (tepeque). Grasshoppers also appear as design motifs in the art of early Middle American cultures (Boning 1971).

Grasshoppers live in all habitats and generally have highly specialized life forms to adapt to prevailing environmental conditions. They seem to prefer open habitats and are most numerous and diverse in grasslands. There are indications that un-derstory species decrease as one enters tropical forests (Brodey 1975), but distinct canopy (Roberts 1973, Descamps 1976) and understory (Rowell 1978) assemblages are evident. There are even successional stages of these categories following clearing of forest (Amedegnato and Descamps 1980).

Many grasshoppers can make sounds by frictional contact between various parts of the body, usually one of the hind leg segments against the fore wings. In the winged lubbers, rapid closing of the hind wings brings serrate veinlets on this wing in contact with scraper veins on the fore wing, producing a snapping or rattling sound. A cracking is often heard from band wings in flight. It is thought to be caused by the partial folding and rapid expansion of the hind wing (Uvarov f966: 176f.).

In addition to the locusts (Schistocerca), which mass in flight, the nymphs of some lubbers also are migratory on foot. Young lubbers also form dense groups on the tops of plants. They are more brightly colored than the adults and are certainly distasteful, a fact advertised more effectively en masse than individually. Lowland and lower montane forest grasshoppers have been found to have narrow feeding preferences (Rowell et al. 1984). Probably, many such feeding specialists are sequestering toxic chemicals from their hosts (Rowell 1978).

Grasshoppers are essentially land insects, but a few have semiaquatic habits in South America. The best-studied examples are Marellia remipes, Paulinia acuminata (fig. 5.5b), and Cornops aquaticum (Pauliniidae), which live on broad, floating leaves of water lilies and other aquatic plants. They frequently fall into the water after a hasty jump. They show clear morphological and behaviorial adaptations to life in water including paddle-shaped hind legs in some species (Bentos and Lorier 1991). Females often insert their eggs into the stems of water plants (Cornops) or place them on the undersides of floating leaves (Marellia and Paulinia) (Carbonell 1959, 1964).

The so-called band-wing grasshoppers sport brightly colored red, blue, purple, green, yellow, or orange hind wings. To this group belong the common, widespread, arid-land species, Trimerotropis pal-lidipennis (fig. 5.5a), recognized by its translucent yellow hind wings. The fore wings are usually cryptically colored to match the gravel or sandy soil on which the species habitually rests. Some grass-loving types (Achurum; fig. 5.5d) are very slender and elongate, better to hide among the blades on which they rest.

With their hind legs held out at right

Figure 5.5 GRASSHOPPERS, (a) Band-wing grasshopper (Trimerotropis pallidipennis, Acrididae). (b) Aquatic grasshopper (Paulinia acuminata, Pauliniidae). (c) American locust (Schistocerca picei-frons, Acrididae). (d) Grass-mimicking grasshopper (Achurum sumichrasti, Acrididae). (e) Eumastacid grasshopper (Eumastax sp., Eumastacidae).

Figure 5.5 GRASSHOPPERS, (a) Band-wing grasshopper (Trimerotropis pallidipennis, Acrididae). (b) Aquatic grasshopper (Paulinia acuminata, Pauliniidae). (c) American locust (Schistocerca picei-frons, Acrididae). (d) Grass-mimicking grasshopper (Achurum sumichrasti, Acrididae). (e) Eumastacid grasshopper (Eumastax sp., Eumastacidae).

angles to the body, Eumastax (Eumastacidae; fig. 5.5e) bask on leaves in the warm pools of sunlight that flood into the forest undergrowth below holes in the canopy (pl. lc). The sunbeams excite the iridescence in the greens, blues, and yellows on the bodies of these forms, making them glow like jewels.

Uvarov (1977: 42If.) presents a faunistic summary of Latin American grasshoppers; Amedegnato (1974) reviews the genera. The geographic and evolutionary history of the regional forms has been traced by various authors (Carbonell 1977, Amedegnato and Descamps 1979).

References

Amedegnato, C. 1974. Les genres d'Acridiens néotropicaux, leur classification par familles, sous-familles el tribus. Acrida 3: 193-203. Amedegnato, C., and M. Descamps. 1979. History and phylogeny of the Neotropical acridid fauna, Metaleptea. Soc. Panamer. Ac-ridiología 2(1): 1-10. Amedegnato, C, and M. Descamps. 1980. Evolution des populations d'Orthopteres d'Amazonie du nord-ouest dans les cultures traditionnelles et les formations secondaires d'origine anthropique. Acrida 9: 1-33. Bentos, A., and E. Lorif.r 1991. Acridomorfos acuáticos (Orthoptera, Acridoidea). I. Adaptaciones morfológicas. Rev. Brasil. Entomol. 35: 631-653.

Bodenheimer, F. S. 1951. Insects as human food. Junk, The Hague. Bûning, K. 1971. Mesoamerikanische Heu-

schreckendarstellungen. Anz. Schádlings-kunde Pflanzenschutz 44: 185-189.

Brodey, K. 1975. A study of grasshopper species composition in primary and secondary growth in Costa Rica. Entomol. News 86: 207-211.

Carbonell, C. S. 1959. The external anatomy of the South American semiaquatic grasshopper Mare Ilia remipes Uvarov (Acridoidea, Pauliniidae). Smithsonian Misc. Coll. 137: 61-97.

Carbonell, C. S. 1964. Habitat, etología y ontongenia de Paulinia acuminata (Dg.), (Acridoidea, Pauliniidae) en el Uruguay. Soc. Uruguayo Entomol. Rev. 6: 39-48.

Carbonell, C. S. 1977. Origin, evolution, and distribution of the Neotropical acridomorph fauna (Orthoptera): A preliminary hypothesis. Soc. Entomol. Argentina Rev. 36: 153-175.

Curran, C. H. 1937. Insect lore of the Aztecs. Nat. Hist. 39: 196-203.

Descamps, M. 1976. La faune dendrophile néotropicale. I. Revue des Proctolabinae (Orth. Acrididae). Acrida 5: 63-167.

Kevan, D. K. McE. 1977. The American Pyrgo-morphidae (Orthoptera). Soc. Entomol. Argentina Rev. 36: 3-28.

Liebermann, J. 1948. Curiosidades históricas acerca de la langosta. Aim. Min. Agrie. Ganad. Buenos Aires 23: 434-438.

Roberts, H. R. 1973. Arboreal Orthoptera in the rain forests of Costa Rica collected with insecticide: A report on the grasshoppers (Acrididae), including new species. Acad. Nat. Sci. Philadelphia Proc. 125: 49-66.

Rowell, C. H. E. 1978. Food plant specificity in Neotropical rain-forest acridids. Entomol. Exper. Appl. 24: 651-662.

Rowf.ll, C. H. E, M. Rowell-Rahier, H. F^. Baker, G. Cooper-Driver, and L. D. Gómez. 1984. The palatability of ferns and the ecol ogy of two tropical forest grasshoppers. Biotropica 15: 207-216. Uvarov, B. 1966, 1977. Grasshoppers and locusts: A handbook of general acridology. 2 vols. Cambridge Univ. Press, Cambridge.

Locusts

Acrididae, Cyrtacanthacridinae, Schistocerca. Spanish: Langostas, langostas voladoras (General). Portuguese: Gafanhotos de praga.

Although not all easily distinguished, twenty to thirty kinds of Schistocerca inhabit tropical America. They are all large (BL 4— 6 cm), slender grasshoppers with expansive wings that extend well beyond the tip of the abdomen when folded. Females are much larger than the males. The fore wings of both sexes are varied in coloration but are generally dull, yellowish with irregular brownish spots; the hind wings are more or less pelucid.

These forms are variable in behavior as well as in coloration. Certain of them produce large swarms and migrate periodically, like the infamous Old World migratory locust (S. gregaria) to which they are closely related. Some of this variation may be caused by developmental influences, especially crowding, leading to so-called phases. There is considerable confusion in the literature regarding the exact species status, interrelationships, and genetic significance of all these forms and phases. In one taxonomic study based on external morphology, the migratory types have been relegated to a single subspecies (S. paranensis) within a widespread species, 5. americana, wherever they occur in Central or South America (Dirsh 1974), while others classify the locusts differently (Harvey 1981). Hybridization experiments, however, show the picture to be still more complex: at least 5. piceifrons (fig. 5.5c), 5. americana, and S. cancellata should be considered separate species (Harvey 1979, Jago et al. 1982), the first being the true swarming pest (Harvey 1983).

Whatever its correct name, this locust is well known in Latin America for its ravages to crops and rangeland from prehistory to modern times. Descriptions of the invasions rival the stories of the Old World species recounted in the Bible and other historical writings. While crossing the dry pampas of Argentina in March 1835, Charles Darwin (1962 [1845]: 330-331) wrote,

Shortly before arriving at the village and river of Luxan, we observed, to the south, a ragged cloud of a dark reddish brown color. At first we thought it was caused by some great fire on the neighboring plains, but we soon found that it was a swarm of locusts. . . . The sound of their wings was as the sound of chariots of many horses running to battle. . . . The sky, seen through the advanced guard, appeared like a mezzotinto engraving; but the main body was impervious to sight. . . . When they alighted, they were more numerous than the leaves in the field, and the surface became reddish instead of green.

These events are known in many parts of the region, most commonly and regularly in northern Argentina and southern Brazil but also to a limited extent in coastal Chile and the Andean mountain valleys of Peru, Ecuador, and Colombia as well as in scattered localities in Central America and Mexico.

The annual patterns of breeding are strongly influenced by the weather and its seasonal variations. Breeding is confined to the period of summer rains. Outbreaks occur in the driest parts of the species' range, triggered by the occasional abundant rainfalls that foster the insect's high reproductive capacity (Hunter and Cosen-zo 1990, Waloff and Pedgley 1986).

In most southern areas, there are two annual generations, beginning with mating and oviposition in November and December. The nymphs hatch and are active and growing from December to April. They become adults through April and May, when the migrations to alternative breeding grounds take place. Here a second mating and egg laying ensues, and the young of this generation produce a whole new brood of adults by September to November which migrates back to the areas of original habitat (Daguerre 1953).

Other Schistocerca species and subspecies overlap the range of the true locusts in diverse parts of Latin America, all of a totally sedentary nature. These include endemic species on many isolated islands in the West Indies, Bermuda, and the Galapagos and Revillagigedo archipelagos.

References

Daguerre, J. B. 1953. Vida de la langosta voladora. Reun. Com. Interamer. Perm. Antiacrid (Puerto Alegre), 1952: 55-79. Darwin, C. 1962 [1845]. The voyage of the Beagle. Edited by L. Engel. Doubleday-Amer. Mus. Nat. Hist, New York. Dirsh, V. M. 1974. Genus Schistocerca. Junk

(Ser. Entomol. 10), The Hague. Harvey, A. W. 1979. Hybridization studies in the Schistocerca americana complex. I. The specific status of the Central American Locust. Biol. J. Linnean Soc. 12: 349-355. Harvey, A. W. 1981. A reclassification of the Schistocerca americana complex. Acrida 10: 61-77.

Harvey, A. W. 1983. Schistocerca, piceifrons (Walker), the swarming locust of tropical America: A review. Bull. Entomol. Res. 73: 171-184.

Hunter, D. M., and E. L. Cosenzo. 1990. The origin of plagues and recent outbreaks oi the

South American locust, Schistocerca cancellata (Orthoptera: Acrididae) in Argentina. Bull. Entomol. Res. 80: 295-300. Jago, N. D., A. Antoniou, and J. P. Grunshaw. 1982. Further laboratory evidence for the separate species status of the South American locust (Schistocerca cancellata Serville) and the Central American locust (Schistocerca piceifrons piceifrons) (Acrididae, Cyrtacanthacridinae). J. Nat. Hist. 16: 763-768. Waloff, Z., and D. E. Pedgley. 1986. Comparative biogeography and biology of the South American locust, Schistocerca cancellata (Serville), and the South African desert locust, S. gregaria flaviventris (Burmeister) (Orthoptera: Acrididae): A review. Bull. Entomol. Res. 76: 1-20.

Lubber Grasshoppers

Romaleidae.

This grasshopper family is found only in the New World and consists currently of forty-eight genera and at least double that number of species, distributed over all the Neotropical Region but not on the Antilles except Cuba (Rehn and Grant 1959). The group is of very diverse morphology but is generally made up of quite large, heavy-bodied forms, including the biggest of the world's grasshoppers, Tropidacris (fig. 5.6a), with body lengths of 8 to 9 centimeters. They are fully winged to apterous, and many have partially developed wings never used for flight. The integument is often granulate or with pronounced, tuberculate points. The thoracic disk usually has a

Figure 5.6 LUBBER GRASSHOPPERS (ROMALEIDAE). (a) Giant grasshopper (Tropidacris cristata). (b) Lubber grasshopper (Taenopoda varipennis). (c) Rainbow-winged grasshopper (77-tanacris gloriosa). (d) Independence grasshopper (Chromacris speciosa).

definite crest but may be wide or simple, like that of other acridids.

The vernacular name of these grasshoppers refers to the terrestrial habits of the majority of species, which is dictated by their flightlessness ("landlubbers"). Unable to fly, they rely on other modes of self-protection, often releasing repugnant secretions from glands or the mouth and emitting threatening sounds. Release of noxious liquids or foams from the meso-thoracic spiracle can be accompanied by a hissing and buzzing of the wings in an imposing threat display.

These are abilities of the common genus Taenopoda, for example, which is represented by several species, including the well-known T. eques, in the drier parts of northern Mexico, down through Central America to Panama, where T. varipennis (fig. 5.6b) takes over. They are usually fond of mimosas and acacias, their primary food plants. Taenopoda are moderately large (BL 6—7 cm) and have only slightly diminutive wings. The fore wings are basically green, with fine, yellow reticulation or dark blotches. The nymphs are black with red gilding and are gregarious. They apparently rely on unpalatability for protection, being so conspicuous in color and vulnerable on exposed, herbaceous vegetation.

Another northern species is Brachystola magna, which prefers grasslands on the Mexican plateau and is confined to a life on the ground because of its almost complete winglessness and inability to climb. The fore wing is only a small disk, the hind wing not much more than a vestigial fan.

Lubbers of the genus Chromacris are usually a glossy green with yellow markings and striking red or yellow wings. The hind wings are various shades of red, orange, or yellow with contrasting black bands. They occur in the humid portions of the American tropics from Mexico to Argentina. All show a preference for solanaceous and composite plants and have gregarious juveniles like other roma-

leids. C. speciosa (fig. 5.6d) is the most wide-ranging and variable species. It is green and yellow, the colors of the Brazilian flag, and has been dubbed the "independence grasshopper" (gafanhoto da independencia) in the republic (Ohaus 1990: 233, as C. miles; Roberts and Carbonell 1982).

References

Ohaus, F. 1990. Bericht über eine entomologische Reise nach Centralbrasilien. Stettiner Entomol. Zeit. 61: 164-273. Rehn, J. A. G., and H. J. Grant, Jr. 1959. A review of the Romaleinae (Orthoptera; Acridi-dae) found in America north of Mexico. Acad. Nat. Sei. Philadelphia Proc. Ill: 109-271. Roberts, H. R., and C. S. Carbonell. 1982. A revision of the grasshopper genera Chromacris and Xestotrachelus (Orthoptera, Romaleidae, Romaleinae). Calif. Acad. Sei., Ser. 4, Proc. 43: 43-58.

Giant Grasshoppers

Romaleidae, Tropidacris, Titanacris. Birdwing grasshoppers, rainbow grasshoppers.

Tropidacris and Titanacris are unusually large, fully winged grasshoppers. The first genus contains only three species, which are 10 to 13 centimeters from head to wing tips and have a wingspan of 25 centimeters or more. A widespread but not common species is Tr. cristata. The second genus, in which there are seven species (e.g., T. velazquezii, T. gloriosa; Descamps and Carbonell 1985), is only slightly smaller, 10 to 11 centimeters in length and with a wing-span of up to 23 centimeters.

Aside from their great size, these grasshoppers are spectacular in flight or when crepitating from perches, when they display their brilliantly colored hind wings. In Tropidacris, these wings are generally red with a solid black marginal zone giving way to a finely checkered gray or bluish pattern toward the wing base. The fore wings are gray-green, splotched with gray, and the posterior part of the pronotum is flat and yellow and green speckled. The hind wing of Titanacris gloriosa (fig. 5.6c) is a veritable rainbow, bright blue basally, grading to crimson anteriorly, and then green over the apical portion. The fore wings are uniformly leaf green, as is the pronotum; the latter has a serrated crest running down the entire middle to distinguish it from Tropidacris, whose crest runs over the anterior half of the pronotum only.

In spite of their conspicuousness, not much has been recorded regarding the life habits of these enormous orthopterans. They are occasionally found on shrubby vegetation but more normally inhabit the crowns of trees and are particularly active on hot days, stridulating and readily taking flight. Tr. cristata has been encountered on plants of the genus Quassia (Simarou-baceae) which contain repellent chemicals that the insect may sequester (Rowell 1983). The immatures are gregarious. Young (pers. comm.) reports the species common on Erythrina (Papilionaceae) in Costa Rica.

References

Descamps, M., and C. S. Carbonell. 1985. Revision of the Neotropical arboreal genus Titanacris (Orthoptera, Acridoidea, Romalei-dae). Soc. Entomol. France Ann. (n.s.) 21: 259-285.

Rowell, H. F. 1983. Tropidacris cristata (salta-monte o Chapulín gigante, giant red-winged grasshopper). In D. H. Janzen, ed., Costa Rican natural history. Univ. Chicago Press, Chicago. Pp. 772-773.

Jumping Sticks

Proscopiidae. Spanish: Palitos vivientes de antenas cortas (General). Portuguese: Chicos magros, gafanhotos de marmeleiro, gafanhotos dejurema, María moles (Brazil).

Jumping sticks are found only on the South American continent, as far north as Panama, and on the Caribbean island of Bonaire. Their biology is incompletely unknown. Specimens are usually seen resting on vegetation, their cryptic stick form and colors giving them a measure of camou flage, especially among grasses, which are a dominant habitat. Some information regarding internal anatomy and cytology has been provided by Ferreira (1978).

There are 153 named species in seventeen genera, but many more probably exist. Some known species may be found to be composed of multiple species when details of their anatomy, such as in the genitalia, are studied (Descamps 1973). Apioscelis (fig. 5.7a) is a typical species.

These orthopterans (Carbonell 1977, Mello-Leitâo 1939) are sticklike in shape, fairly large (adult BL 5—10 cm), and easily mistaken for walkingsticks (Phasmatodea) (Liana 1972). The slightly dilated hind femur, elongate thorax, and vertical, cone-shaped grasshopper-type head distinguish them, however. Also, the antennae are short and have few segments like the grasshoppers, which are their closer relatives but from which they differ by having a vertical head and an elongate prothorax that lacks a dorsal shield. The portion of the head anterior to the eyes may be extremely prolonged in some genera. Wings are completely missing in almost all and at most are minute vestiges, and they lack tympanic and stridulatory organs. They are mostly dull colored, solid olive to brown, although some have black, red, or yellow markings.

References

Carbonell, C. S. 1977. Superfam. Prosco-poidea, Fam. Proscopiidae. In M. Beier, ed., Orthopterum Catalogus. Junk, The Hague. Pp. 1-29.

Descamps, M. 1973. Notes préliminaires sur les genitalia de Proscopoidea (Orthoptera Ac-ridomorpha). Acrida 2: 77-95. Ferreira, A. 1978. Contribuiçào ao estudo da evoluçâo dos Proscopiidae (Orthoptera-Pros-copoidea). Studia Entomol. 20: 221-233. Liana, A. 1972. Etudes sur les Proscopiidae (Orthoptera). Polska Akad. Nauk, Inst. Zool., Ann. Zool. 29: 381-459. Mello-Leitâo, C. 1939. Estudio monográfico de los Proscópidos. Mus. La Plata Rev., Nov. Ser., Zool. 8(1): 279-449.

Figure 5.7 JUMPING STICK AND WALKINGSTICKS. (a) Jumping stick (Apioscelis sp., Proscopi-idae). (b) Giant walkingstick (Phibalosoma phyllinum, Phibalosomatidae). (c) Chinchemoyo (Paradoxo-morpha crassa, Anisomorphidae). (d) Winged walkingstick (Pseudophasma ?, Pseudophasmatidae).

walking sticks

Phasmatodea (= Phasmatoptera,

Phasmida, Phasmodea). Spanish: Bichos palitos, zacatones (General); chinchemoyos, palotes (Chile); campamochas (Mexico); palitos vivientes (Peru). Portuguese: Bichos pau. Phasmids.

A greatly attenuated, sticklike body and legs are the hallmarks of these common but seldom seen insects. Their resemblance to twigs and leaves is so perfect that they are usually discovered in their natural haunts only by accident. Human eyes can play time and again over a specimen in its resting place and never see it. Some in central South America are among the largest insects as measured by length. Bactri-dium grande (female BL 26 cm) is the biggest; Phibalosoma phyllinum (fig. 5.7b) and Otocrania aurita both are over 20 centimeters long.

There are both winged (fig. 5.7d) and wingless stick insects, a tendency toward the latter more in females than in males. When present, the hind wings only are well formed, and then they are large, fanlike, and efficient flight organs. The fore wings are much reduced, often only scalelike cups or elongate leathery plates.

In general, the group (Bedford 1978) shows a number of interesting biological as well as structural features, but little specific information is available on the Neotropical species (Willig et al. 1986, Zapata and Torres 1970). All feed on plants and are apparently fairly host specific. Parthenogenesis occurs in a number of European forms and presumably also occurs in regional mantids. An unexplained characteristic of some female walkingsticks is a bright red color at the base of the fore femur. Individuals can regenerate lost limbs, and those of some species can change color to match their background.

Defensive behaviors, coupled with their cryptic forms and colors, are well developed and parallel to some extent those of mantids. They include (1) rocking motions in which the body is swayed from side to side by flexing of the legs at the upper joints, an action thought to enhance resemblance to plant parts moving in the breeze; (2) active escape by dropping or flight; (3) flashing of wings to startle or display aposematic colors; (4) catalepsy, or freezing or feigning death; (5) sound production by wing rattling; (6) fighting with the legs; and (7) release of repugnant or caustic chemicals. Paradoxomorpha (fig. 5.7c) can fire an aerosol spray that can blister human skin. The substance has been analyzed as containing ethyl ether or ortho-formic acid and is produced by a pair of immense glands in the thorax that exit

Figure 5.7 JUMPING STICK AND WALKINGSTICKS. (a) Jumping stick (Apioscelis sp., Proscopi-idae). (b) Giant walkingstick (Phibalosoma phyllinum, Phibalosomatidae). (c) Chinchemoyo (Paradoxo-morpha crassa, Anisomorphidae). (d) Winged walkingstick (Pseudophasma ?, Pseudophasmatidae).

through an opening on either side behind the head (Moreno 1940). This is a rather robust stick insect, fairly common in parts of southern Argentina and Chile where it is known by several vernaculars in Que-chua (chinchemoyo, "stinking chest") and Mapuche (tabolongo, chirindango, fitquilen) (Schneider 1934).

A single species may employ a variety of these tactics. Pterinoxylus spinulosus from Panama enhances its resting posture resemblance to sticks by closely folding the mid-and hind legs, which then look like small shoots from the main stick (Robinson 1968).

phasmid eggs are curiously shaped, looking like seeds with a hard shell and either smooth and shiny and unicolorous or heavily sculptured and patterned. All have an operculum. They are placed carefully on the host plant or dispersed by flicking movements of the abdomen or scattered indiscriminately.

Stick insects are found in all habitats but are most abundant and diverse in humid forests. Two species, Bostra scabrinota and Libethra minuscula, are typical of the lomas or seasonal herblands of the coastal Peruvian desert. Developmental stages exhibit conspicuous changes of color corresponding to the flourishing and waning of this vegetation that they mimic. They pass the long dry season as eggs on the soil surface (Aguilar 1970).

Four ceratopogonid gnats in the subgenus Microhelea of Forcipomyia attach to stick insects and suck their blood. With the exception of one Indonesian example, these phasmid parasites, called "stick ticks," are known only from tropical America (Wirth 1971).

The order has been newly reclassified into six families (Bradley and Galil 1977) and its world distribution reviewed (Gun-ther 1953). A high percentage, perhaps 30 percent of more than 2,500 world species, live in Latin America, including the West Indies (Moxey 1972).

References

Aguilar, P. G. 1970. Los "palitos vivientes de Lima." 1. Phasmatidae de las lomas. Rev. Peruana Entomol. 13: 1-8.

Bedford, G. O. 1978. Biology and ecology of the Phasmatodea. Ann. Rev. Entomol. 23: 125-149.

Bradley, J. C., and B. S. Galil. 1977. The taxonomic arrangement of the Phasmatodea with keys to the subfamilies and tribes. Entomol. Soc. Wash. Proc. 79: 176-208.

Gunther, K. 1953. Uber die taxonomische Gliederung und die geographische Verbreitung der Insektenordnung de Phasmatodea. Zeit. Entomol. 3: 541-563.

Moreno, A. 1940. Glándulas odoríferas en Paradoxornorpha. Mus. La Plata Not. (Zool. 45) 5: 319-323.

Moxey, C. F. 1972. The stick-insects (Phasmatodea) of the West Indies: Their systematics and biology. Ph.D. diss., Harvard Univ. [Not seen.]

Robinson, M. H. 1968. The defensive behavior of Pterinoxylus spinulosus Redtenbacher, a winged stick insect from Panama. Psyche 75: 195-207.

Schneider, C. O. 1934. Las emanaciones del chinchemoyo Paradoxornorpha crassa (Blanch, Kirby). Rev. Chilena Hist. Nat. 38: 44-46.

Willig, M. R., R. W. Garrison, and A. J. Bauman. 1986. Population dynamics and natural history of a Neotropical walkingstick, Lamponium portoricensis Rehn (Phasmatodea: Phasmatidae). Texas J. Sei. 38: 121-137.

Wirth, W. W. 1971. A review of the "stick-ticks," Neotropical biting midges of the Forcipomyia subgenus Microhelea parasitic on walkingsticks (Diptera: Ceratopogonidae). Entomol. News 82: 229-245.

Zapata, S., and E. Torres. 1970. Biología y morfología de Bacteria granulicollis (Blan-chard) (Phasmida). Univ. Chile, Cen. Est. Entomol. Publ. 10: 23-42.

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