Leaf beetles

Chrysomelidae. Spanish: San Juanes, pololos (Chile, metallic green types).

This is an immense family with over 12,000 species in the Neotropics. Adults range in size from very small (BL 1.5 mm) to moderate (BL 20-22 mm) and are of varied body form. Although some species resemble long-horned beetles (all tarsi with apparently four segments), most are oval or much flattened, and they never have antennae longer than half their body length. They are often brightly colored, spotted or striped, and many are brilliant metallic green, blue, or gold. Many are good jumpers; some tiny species may have greatly developed hind legs for hopping and are called "flea beetles" (Alticinae, pulgas saltonas) (Scherer 1983).

All are plant feeders in both the larval and adult phases and sometimes are serious agricultural pests, for example, the large Neotropical genus Diabrotica (asparagus beetles, catarinitas, vaquitas, vaquinhos) (fig. 9.15a). The larvae are stem borers; the adults attack principally the new leaves and may riddle them with holes or completely strip away the tissue between the veins (skeletonizing). Such leaves are a common sight among otherwise healthy lush vegetation in the tropical lowlands (Carroll 1978). Others are leaf miners.

Larvae are frequently gregarious. Under stress, some leaf beetles exude a yellow fluid presumed to render them noxious or poisonous to predators.

Most of the nineteen subfamilies are represented in Latin America (Seeno and Wilcox 1982). The tortoise beetles (Cassidi-nae) and the mining leaf beetles (His-pinae), discussed below, contain the most common species. Some species in the genus Diabrotica (Galerucinae; Smith and Lawrence 1967) are also conspicuous and are agricultural pests. Although several species of the well-known aquatic subfamily Donaciinae live on floating and emergent water plants in Mexico, Central America, and Cuba, none are known to occur in South America.

References

Carroll, C. T. 1978. Beetles, parasitoids and tropical morning glories: A study in host discrimination. Ecol. Entomol. 3: 79—85. Scherer, G. 1983. A diagnostic key for the Neotropical alticine genera (Coleoptera: Chrysomelidae: Alticinae). Entomol. Arbeit. Mus. Frey 31/32: 1-89. Seeno, T. N., and J. A. Wilcox. 1982. Leaf beetle genera (Coleoptera: Chrysomelidae). Entomography 1: 1-221. Smith, R. E, and J. F. Lawrence. 1967. Clarification of the status of the type specimens of Diabrocticites (Coleoptera, Chrysomelidae, Galerucinae). Univ. Calif. Publ. Entomol. 45: 1-168.

Rflure 9.15 LEAF BEETLES (CHRYSOMELIDAE). (a) Spotted cucumber beetle (Diabrotica undecempunctata). (b) Horned tortoise beetle (Omocerus eximius). (c) Tortoise beetle (Stolas cyanea). (d) Target tortoise beetle (Charidotis circumducta). (e) Tortoise beetle (Acromis spinifex), male (from female eggs on filament), (f) Rolled-leaf beetle (Chelobasis bicolor). (g) Rolled-leaf beetle, tafva. (h) Giant leaf beetle (Pseudocalaspidea cassidea).

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