Nervewinged insects

Neuroptera.

The most characteristic feature of adult neuropterans is their well-developed wing venation, with highly complex vein-branching patterns, end twigging of the main veins, diverse polygonal cells in the middle areas, and frequent stair-step pathways of many vein branches. A few small groups are atypical, however, in having much simplified venation or wings very much reduced in size (brachypterous). Four equal size and shape wings are the rule; they are held roofwise over the body when not in use for flight. The wing membrane is usually clear but may sometimes be brown pigmented or rarely may have bright color spots and fields; it is completely whitish opaque in the dusty wings (Coniopterygidae). The mouthparts are mandibulate, and the head possesses long, many-segmented, filiform antennae and well-formed compound eyes. A few families have well-developed ovipositors.

Most neuropteran adults are rather drably colored in cryptic greens, browns, and grays. Several unrelated types, however, form an aposematic mimetic complex in southern South America, all having a similar pair of bright red stripes on the prothorax near the openings of scent glands that produce a noxious, skunklike (contains skatol) odor. Some also have conspicuous patterns on the wings. Among these are ant lions (Myrmeleontidae), such as Dimares, Glenurus, and Maracandula, some chrysopids, and mantispids. The mantispid genus Climaciella mimics large social wasps, whereas the genus Anchieta resembles stingless bees. The largest mantispid in the world, Drepanicus gayi from Chile, looks like a green katydid. Ant lions are cryptically patterned to match their daytime resting sites (Stange 1970).

The general form of the larvae varies greatly, but many resemble ground beetle larvae. Some have peculiarly modified elongate, curved jaws, formed like tongs to grasp insect prey. Each has an internal canal through which the juices of the food are siphoned. Many larvae are hairy or spiny.

The larvae of some Chrysopidae bear hooked bristles on their backs to which they fix minute bits and pieces of debris to give them a kind of camouflage (a habit that parallels the decorator crabs in coral reefs and the North American Chrysopa slossonae, which attaches bits of the wax secretions of its woolly aphid prey to its body to mask it from recognition by the ants that protect this aphid (Eisner et al.

1978). Such "trash-carrying lacewings" belong to the genera Leucochrysa and Ceraeo-chrysa. Larval habitats vary considerably and include vegetation, sandy soil, bark crevices, and cavities under objects on the ground. A few ant lion larvae (Glenurus) are also trash carriers.

Hardly anything has been published on the biology of the immatures of the Neotropical fauna except for a few beneficial types such as the Chrysopidae (Nunez 1989a, 19896) and Hemerobiidae, the larvae of which are voracious predators of homopterous pests (aphids and scale insects, primarily) and thus of considerable value as biocontrol agents (New 1975). Species of Chrysoperla (fig. 5.15b) are even reared in insectaries to be broadcast on crops for this purpose. Mantispids (fig. 5.15a) are spider egg predators (Biraben 1960) or bee parasites (Parker and Stange 1965).

Penny (1977) lists approximately 950 Latin American species of Neuroptera. These are distributed among eleven families, the largest and most common of which are the ant lions (Myrmeleontidae), dusty wings (Coniopterygidae), and green lacewings (Chrysopidae). There are three neuropteran subfamilies found only in the Neotropical Region: the Platymantispinae, of uncertain affinity but usually placed in the Mantispidae, are strange subterranean predators (Parker and Stange 1965); the

figure 5.15 NEUROPTEROUS INSECTS, (a) Mantispid (Climaciella sp„ Mantispidae). (b) Green ■Wwing (Chrysoperla sp., Chrysopidae). (c) Ant lion (Myrmeleon sp., Myrmeleontidae), larva in pit. Ant lion (Glenurus peculiaris, Myrmeleontidae). (e) Owlfly (Corduleceris maclachlani, aphidae).

Brucheiserinae, two species of dusty wings found under rocks and possibly flightless; and finally the Albardinae, containing one unique, highly modified owlfly species (Penny 1985).

References

Birabén, M. 1960. Mantispa parásita en el cocón de Metepeira. Neotropica 6: 61—64. Eisner, T., K. Hicks, M. Eisner, and D. S. Robinson. 1978. "Wolf-in-sheep's-clothing" strategy of a predaceous insect larva. Science 199: 790-794. New, T. R. 1975. The biology of Chrysopidae and Hemerobiidae (Neuroptera), with reference to their usage as biocontrol agents: A review. Royal Entomol Soc. London Trans. 127: 115-140. Nuñez, E. 1989a. Chrysopidae (Neuroptera) del Perú y sus especies más comunes. Rev. Peruana Entomol. 31: 69-75. Nuñez, E. 19896. Cíelo biológico y crianza de Chrysoperla externa y Ceraeochrysa cincta (Neuroptera, Chrysopidae). Rev. Peruana Entomol. 31: 76-82.

Parker, F. D., and L. A. Stange. 1965. Systematic and biological notes on the tribe Platy-mantispini and the description of a new species of Plega from Mexico. Can. Entomol. 97: 604-612. Penny, N. D. 1977. Lista de Megaloptera, Neuroptera e Raphidioptera do México, América Central, ilhas Caraibas e América do sul. Acta Amazónica 7 (4) suppl.: 1—61. Penny, N. D. 1985 [1983], Neuroptera of the Amazon Basin. Pt. 9. Albardiinae. Acta Amazónica 13(3-4): 697-699. Stange, L. A. 1970. Revision of the ant-lion tribe Brachynemurini of North America. Univ. Calif. Publ. Entomol. 55: 1-192.

Ant Lions

Neuroptera, Myrmeleontidae.

These are probably the best-known neurop-terans, not because of the adults but because of the work of the larvae, the familiar, funnel-shaped ant lion pits commonly seen in fine sandy soil. These are constructed in places protected from rain: under staircases and by the edges of elevated buildings, beneath overhanging rocks or logs, and near the bases of trees. They may be very numerous and occur in large, concentrated groups at times (McClure 1976) Only larvae of the genus Myrmeleon make these death traps, into which ants or other small, terrestrial insects fall (Wilson 1974) (Pit making is found in a few other groups [Brachynemurus in Argentina and Mexico], but tubes extend downward from the pits.) The escape of the hapless insect is prevented by the constantly failing sloped sides of the pit. The ant lion at the bottom also flicks sand onto the struggling prey to dislodge it and cause it to tumble down to the neck of the funnel. The larva waits there, buried, only its ice-tongjaws projecting above the surface. These formidable structures close on the prey, the tips piercing its body, and take its blood through internal canals. These larvae only move backward, a trait shared by the giant Vella larvae that often prey on them (Stange pers. comm.). The meandering subsurface burrows of the latter common Neotropical genus are often evident in loose sandy areas.

Other ant lion larvae merely burrow in sand or loose soil, searching for other subterranean insects to be captured directly and eaten. Many can dig rapidly in reverse by repeatedly arching the abdomen forward under the body. Some ant lions that live in dry tree holes (e.g., some Glenurus; Miller and Stange 1983) or on tree bark or bare rock surfaces (Navasoleon; see Miller and Stange 1985) have diminished or lost their ability to dig backward.

Ant lion larvae (fig. 5.15c) are small (BL 5-10 mm), ovoid creatures with a boxlike head and typical neuropteran sickle-shaped jaws. They usually have enlarged bristles at the rear end, employed in rapid digging, and have their eyes on stalks. The abdomen is bulbous and the anterior portion steep, so that the head and thorax emerge very low.

Adult myrmeleontids are mostly fairly large (BL 3-4 cm), with a very long, slender abdomen, sometimes twice as long as the wings in the male. The wing venation is very complex: there is a very long ce]l under the stigma spot in both wings; the conspicuous vein forking in the middle of the wings near the base looks identical in the fore wing and hind wing but actually involves totally different crossveins (Stange 1970); the subcostal area of the wing is the only part lacking cross veins. The antennae are short, thickened, and expanded at the tip into a club. Males of many species have claspers at the tip of the abdomen and a peculiar brush at the base of the hind wing. Most are dully marked with brown and black speckling on the body and transparent wings, but a few have conspicuously marked wings, such as Morocordula apicalis from southern Mexico and species of Glenurus (fig. 5.15d) and Dimarini (Stange 1989).

There are 35 genera in Latin American containing 224 species (Penny 1977).

References

McClure, M. S. 1976. Spatial distribution of pit-making ant lion larvae (Neuroptera: Myrmeleontidae): Density effects. Biotropica 8: 179-183.

Miller, R. B., and L. A. Stance. 1983. The antlions of Florida: Glenurus grains (Say) (Neuroptera: Myrmeleontidae). Fla. Dept. Agrie. Entomol. Circ. 251: 1—2. Miller, R. B., and L. A. Stance. 1985. Description of the antlion larva Navasoleon boliviana Banks with biological notes (Neuroptera; Myrmeleontidae). Neuroptera Intl. 3: 119-126. Penny, N. D. 1977. Lista de Megaloptera. Neuroptera e Raphidioptera do México, América Central, ilhas Caraibas e América do sul. Acta Amazónica 7(4) suppl.: 1-61. Stance, L. A. 1970. Revision of the ant-lion tribe Brachynemurini of North America. Univ. Calif. Publ. Entomol. 55: 1-192. Stance, L. A. 1989. Review of the New World Dimarini with the description of a new genus from Peru (Neuroptera: Myrmeleontidae). Fla. Entomol. 72: 450-461. WipoN, D. S. 1974. Prey capture and competition in the ant lion. Biotropica 6: 187-193.

Owlflies

Neuroptera, Ascalaphidae.

Looking somewhat like dragonflies but actually related to ant lions, these are medium-sized to large (BL 2—4 cm, BWL to 10 cm) neuropterans with reticulate wing venation. The wings are often infused with brown or black, although they are usually crystalline except for the small stigmal spot near the anterior edge of the tip. They have large, many-faceted eyes, and the antennae are characteristically long and filamentous, with a large, flat, terminal knob, somewhat like those of butterflies. The anterior part of the head, thorax, and legs is frequently hairy. Males of some species have a pronounced elongate dorsal process on the second abdominal segment.

Owlfly larvae are nonburrowers, living openly on leaves, on tree trunks, or on the ground. They are similar to those of ant lions but lack the enlarged digging claw on the hind leg. Almost all species have hairy, fingerlike processes on the body, which are rare in ant lions (Henry 1976). They are slow-moving and usually wait in ambush for prey. The pupa is protected by a weak cocoon woven entirely of silk by the mature larva. Another peculiarity of the group is the laying of deformed eggs (repagula) around the fertile ones (New 1971).

Biological information on the family in the Neotropics is meager. Adults of the genus Corduleceris (fig. 5.15e), unique in having strongly dimorphic sexes, have been observed to aggregate at the tips of tree branches overhanging streams (Covell 1989, Hogue and Penny 1989). The purpose of this behavior is unknown, although the clusters may be composed of sleeping individuals. Single adults often rest on twigs, head downward, with wings and the antennae held closely parallel to the surface, the abdomen sharply erect. They are usually excellent fliers, although they sometimes elect to catch other insects while foraging from leaf surfaces rather than on the wing. There are both nocturnal and diurnal species. The former come to artificial light occasionally.

The family is fairly diverse in Latin America. Penny (1977) lists 94 species in 15 genera, the largest and most common of which are Ululodes and Ameropterus. There are two large groups separated by the form of the eye, those with split eyes, that is, with the eye partially divided by a transverse groove, and those with entire eyes. A third subfamily, represented in the New World only by Albardia furcata in Brazil, is peculiar in the very short antennae and woolly abdomen of the adult (Penny 1983).

References

Covell, Jr., C. V. 1989. Aggregation behavior in a Neotropical owlfly, Cordulecerus mac-lachlani (Neuroptera: Ascalaphidae). Ento-mol. News 100: 155-156.

Henry, C. S. 1976. Some aspects of the external morphology of larval owlflies (Neuroptera: Ascalaphidae), with particular reference to Ululodes and Ascaloptynx. Psyche 83: 1—31.

Hogue, C. L., and N. D. Penny. 1989. Aggregations of Amazonian owlflies (Neuroptera: Ascalaphidae: Cordulecerus). Acta Amazónica 18:359-361

New, T. R. 1971. Ovariolar dimorphism and repagula formation in some South American Ascalaphidae. J. Entomol. 46: 73-77.

Penny, N. D. 1977. Lista de Megaloptera, Neuroptera e Raphidioptera do México, América Central, ilhas Caraibas e América do sul. Acta Amazónica 7(4) suppl.: 1-61.

Penny, N. D. 1983. Neuroptera of the Amazon Basin. Acta Amazónica 13: 697-699.

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