Sunday, December 12, 2010

Metalmark Butterflies


The Riodinidae, also known as Metalmarks, are members of the superfamily Papilionoidea, the true butterflies. They usually live in the tropical places, especially those in the Americas, and about 1,300 species are known. They vary widely in color, but they generally have wing spots with a metallic sheen. Some species of metalmark butterflies are endangered including Lange's metalmark, found in California and the Swamp Metalmark found in isolated locations in the Midwest.



Form and Function

Small to medium in size, metalmarks vary widely in their patterns, behavior, and postures. Males have reduced front legs that are not used for walking, and females have three pairs of walking legs. Adults usually perch with their wings spread open or cocked slightly, while many tropical species normally perch upside down on large leaves. Males locate mates by perching, rather than patrolling. Egg shape varies widely, but caterpillars are typically slug-shaped. Metalmarks overwinter in the larval or pupal stage.


Metalmarks have strong muscles in their thorax which force their wings up and down on a fulcrum basis. They actually go in a slanted figure 8 motion that propels them forward through the air like an airplane.

Eating Habits

The Metalmark uses its very long proboscis, which is like a straw, to sip nectar from flowers. When it is not feeding, the proboscis rolls up onto itself into a flat "ball".


Like some other butterflies, Metalmarks use plant toxins as protection. These defense mechanisms are effective only if they are also well advertised and this has led to the evolution of bright colors in butterflies. This signal may be mimicked by other butterflies. These mimetic forms are usually restricted to the females.


Within the males' abdomen are the sperm producing organs. When the male mates, a set of "claspers" at the end of the abdomen will open and clamp down on the female's abdomen. Butterflies mate facing in opposite directions with their abdomens attached. The penis enters the female at the same location where the eggs come out. The sperm enters a small storage pouch inside the females abdomen. After mating, the female has about 100 eggs inside her and a pouch full of the male spermatozoa. Once gravid, she will perform a kind of self-fertilization. When she places an egg on a plant. One spermatozoa will fertilize the egg and determine its sex. When the egg is first placed on the leaf, it was fertilized less than a second before. Human Impact

Metalmarks like most butterflies help to pollinate other flowers.

Journal Entry

In the article that I read, it talked about how Lange's Metalmark Butterfly is an endangered species. Lange's Metalmark is known to be in the Antioch Dunes National Wildlife Refuge, established largely for the butterfly's protection in 1980. The butterfly's numbers began to decline when the growth of San Francisco led to the dunes being mined heavily for sand.

Works Cited

Answers to kids' questions about butterflies. (n.d.). Retrieved from

Lange's metalmark butterfly . (n.d.). Retrieved from

Lange's metalmark butterfly (lepidoptera: riodinidae) . (n.d.). Retrieved from

How to identify metalmark butterflies . (n.d.). Retrieved from

Wikipedia. (n.d.). Retrieved from

Metalmark butterflies . (n.d.). Retrieved from

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