Metalmarks

Lycaenidae, Riodininae (= Erycinidae, Nemeobiidae).

Such a large proportion of the species of this very diverse subfamily (over 90% of the world's 1,500 or so species, separated into 150 genera) live in the Neotropics that they could be considered the most characteristic butterflies of the region. Most are small (WS 20-35 mm) and delicately built, and their colors and shapes are so varied as to defy description. Many are vividly and extremely beautifully hued with metallic blues, deep scarlet, green, white, and other colors, often in complex combinations and designs (e.g., Amarynthis menaria; fig. 10.16d). Many have metallic gold or silver flecks on the undersides, and a few have eyespots. Some take the patterns of distasteful models among the other Lepidoptera. The wings may be rounded or angular and in some cases flamboyantly multitailed (Heli-copis; fig. 10.16a), resembling hairstreaks, or with single, long "swallowtails" (Chlo-rinea; fig. 10.16c). Adults are fast fliers generally but often settle repeatedly on the same perch, with their resplendent wings outstretched. Some display a "false head" posteriorly on the undersides of the wings, as do the hairstreaks (see hair-streaks, below) (Robbins 1985).

The early stages of few are recorded in the scientific literature. In these, food plants are varied, and the larvae are elongate and sluglike with small lateral expansions held closely appressed to the substratum. The dorsum of the larva's prothorax is thickened and rigid and usually brown in contrast to the rest of the body and often with hornlike projections or large bristles on either side. Most are greenish or pale with many short body hairs; some have brilliantly colored protuberances marking external glands that produce exudates avidly sought by ants (De Vries 1989, Ross 1985).

Some metalmark larvae are participants in mutualistic associations with ants (as in Juditha molpe; fig. 10.16b), obtaining their protection in exchange for these substances (Boulard 1981, Callaghan 1977, Horvitz et al. 1987). It is suspected that the phenomenon is widespread through the subfamily. Ants actually build shelters for one species (Ross 1966). The caterpillar of one species (Thisbe irenea) not only feeds on leaf tissue but also drinks the extrafloral nectar of its host plant, creating a conflict between plant and herbivore for the attentions of ants (De Vries and Baker 1989).

References

Boulard, M. 1981. Nouveaux documents sur les chenilles de lycenes tropicaux. Alexanor 12: 135-140. Callaghan, C. J. 1977. Studies on restinga butterflies. 1. Life cycle and immature biology of Menander felsina (Riodinidae), a myrme-cophilous metalmark. J. Lepidop. Soc. 31: 173-182.

De Vries, R 1989. The ant associated larval organs of Thisbe irenea (Riodinidae) and their effects on attending ants. Zool. J. Linnean Soc. 94: 379-393.

De Vries, R J., and 1. Baker. 1989. Butterflv exploitation of an ant-plant mutualism: Add ing insult to herbivory. New York Entornol Soc. J. 97: 332-340.

Horvitz, C. C., C. Turnbull, and D. J. Harvey. 1987. Biology of immature Eurybia elvina (Lepidoptera: Riodinidae), a myrmecophi-lous metalmark butterfly. Entornol. Soc Amer. Ann. 80: 513-519.

Robbins, R. K. 1985. Independent evolution of "false head" behavior in Riodinidae | Lepidop. Soc. 39: 224-225.

Ross, G. N. 1966. Life-history studies on Mexican butterflies. IV. The ecology and ethology of Anatole rossi, a myrmecophilous metalmark (Lepidoptera: Riodinidae). Entornol. Soc Amer. Ann. 59: 985-1004.

Ross, G. N. 1985. The case of the vanishing caterpillar. Nat. Hist. 94(11): 48-55.

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