Gossamer-Winged Butterflies, Family Lycaenidae

Blues, Coppers, Hairstreaks, and Harvesters

Bronze copper, a gossamer-winged butterfly.
The bronze copper is one of the small but brilliant gossamer-winged butterflies. Kevin D. Arvin, Bugwood.org

The gossamer-winged butterflies may be small, but they attract attention with their shimmering wings. The family Lycaenidae includes hairstreaks, coppers, blues, and harvesters. The term gossamer refers to a delicate and light material, and the wings of these butterflies do indeed appear fragile.

Description:

Most gossamer-winged butterflies appear iridescent, thanks to light-refracting scales on their wings.

Many species are brightly colored, with blue, red, or copper markings, though some are drab. Lycaenid butterflies ranges from tiny to small in size, with slender bodies and narrow heads. Other common traits of most gossamer-winged butterflies include banded antennae (usually ringed in white), and in males, shortened front legs with no tarsal claws.

Some members of this group – hairstreaks, in particular – exhibit "false heads" to fool predators. In these butterflies, the hindwings bear slender tails and color spots, mimicking antennae and eyes. A study at the University of Florida showed that the red-banded hairstreak, Calycopis cecrops, consistently escaped predation by a jumping spider thanks to this trickery.

Caterpillars of this family are slug-like in appearance: short, wide, and rather flat. Their bodies are usually covered in short setae. When it's not feeding, a lycaenid larva will usually retract its head into its thorax.

Classification:

Kingdom – Animalia
Phylum – Arthropoda
Class – Insecta
Order – Lepidoptera
Family - Lycaenidae

Diet:

Most adult butterflies in this family visit flowers to drink nectar. Some adult hairstreaks and harvesters feed on aphid honeydew.

Gossamer-winged caterpillars have some interesting and varied feeding habits.

Like other Lepidopteran larvae, most feed on plants, and caterpillars in this family often specialize on eating a certain type of host plant. Several hairstreak caterpillars, for example, feed on mistletoe. The great purple hairstreak specializes on American mistletoe. Some lycaenid caterpillars prey on ant larvae, and a few species are believed to eat lichen.

Life Cycle:

Like all butterflies, gossamer-winged butterflies undergo complete metamorphosis with four life stages: egg, larva, pupa, and adult. Mated females deposit eggs, which are usually round and flat in shape, singly on or near the host plant. Lycaenid larvae generally leave the host plant and conceal themselves in leaf litter or under bark before pupating. Pupae are often cryptically colored to avoid predation. Gossamer-winged butterflies overwinter in either the egg or pupal stage.

Special Behaviors and Defenses:

The majority of gossamer-winged butterflies are myrmecophilous as larvae, meaning they live in close association with ants. These caterpillars excrete sugary carbohydrates via specialized nectary organs, much like the ant-attracting honeydew produced by aphids. The ants are so enamored of the sweet secretions, that they tend the larvae, keeping them free of parasitoids and safe from predators.

This arrangement isn't always mutually beneficial, however, because in some lycaenid species, the caterpillars turn on their ant caretakers. These caterpillars may eat the larvae, eggs, or pupae of their protectors.

Range and Distribution:

Over 4,750 species belong to the family Lycaenidae, although only about 160 of these butterflies inhabit North America (north of Mexico). Hairstreaks live mostly in the tropics, while coppers inhabit boreal, montane, and northern temperate regions. Harvesters are Old World inhabitants, living mostly in Africa and Indonesia. Blues are the most widely distributed of the Lycaenids, with populations in both temperate and tropical zones.

 

Sources:

  • Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.