Mining Leaf Beetles

Chrysomelidae, Hispinae. Spanish: Abejones del platanillo (Costa Rica).

Larvae of this subfamily are either leaf miners or surface feeders. They are very flat, smooth, and oval, somewhat resembling cockroach nymphs or water pennies (the larvae of the aquatic beetle family Psephenidae). The integument is also strongly sclerotized. The adults have hard, elongate bodies, a large head visible from above, and coarsely sculptured, sometimes almost reticulate, elytra. In some, the outer posterior corners of the elytra are protracted into points.

One group, the so-called rolled-leaf hispine beetles (Harvey 1988; Strong 1977, 1983), are almost exclusively feeders on members of the ginger order (Zingibe-rales, Heliconia, Zingiber, and relatives). Species like Chelobasis bicolor (fig. 9.15f) spend their entire life cycle in the young, scrolllike, rolled leaves of heliconias (Seifert 1982), ginger, and marantas and occur virtually nowhere else. The larvae (fig. 9.15g) stay out of sight between the leaf layers near the bottom; adults feed on tissue near the top of the leaf. Adults and larvae feed at night by scraping the leaf surface, crawling forward with each scoop of the mandibles, and defecating, thus leaving a linear trail often littered with fecal pellets. They do not puncture the leaf. Because of the low nitrogen content in the Heliconia leaves, larval development of these beetles is prolonged and may require over two hundred days. As many as eight species may intermingle at a single site, leading to narrow host specificity (Strong 1982). Xenarescus monocerus larvae, of Venezuela, feed first on young Heliconia inflorescences, apparently to avoid competition with other species, moving later to rolled leaves to complete their development (Seifert and Seifert 1979).

Pseudocalaspidea cassidea (fig. 9.15h) is a very large hispine (BL 25 cm), whose teardrop-shaped body is margined broadly in red, leaving a large black triangular area centrally. Its larva is unknown, although adults are common on understory vegetation in humid forests.

References

Harvey, R. 1988. The ecology of arthropod communities associated with Heliconia leaf-curls in Tambopata Wildlife Preserve, southeastern Peru. The Entomologist 107: 11-19. Seifert, R. P. 1982. Neotropical Heliconia insect communities. Quart. Rev. Biol. 57: 1-28. Seifert, R. P., and F. H. Seifert. 1979. Utilization of Heliconia (Musaceae) by the beetle Xenarescus monocerus (Oliver) (Chrysomelidae: Hispinae) in a Venezuelan forest. Biotropica 11: 51-59.

Strong, Jr, D. R. 1977. Rolled-leaf hispine beetles (Chrysomelidae) and their Zingibe-rales host plants in Middle America. Biotropica 9: 156-169. Strong, Jr., D. R. 1982. Potential interspecific competition and host specificity: Hispine beetles on Heliconia. Ecol. Entomol. 7: 217-220. Strong, Jr., D. R. 1983. Ckelobasis bicolor (abejori del platanillo, rolled-leaf hispine). In D. H. Janzen, ed., Costa Rican natural history. Univ. Chicago Press, Chicago. Pp. 708-711.

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