Story Behind the Science
Butterflies of the Riodinidae family are commonly referred to as metalmarks because of their wings, which have metallic markings on them. Here, we will shorten their family name and call them Rio butterflies. Many butterflies in this family are brightly colored, but others look more dusty and dull. Some species of Rios often resemble other families of butterflies due to their variety in shape and color pattern. In addition to their diversity in shape, color and size, Rio butterflies have a wide range of unique behaviors and postures as well. These insects can often be seen perched on leaves with their wings open or slightly angled, and many of them sit like this on the underside of leaves as well.
Some of the greatest threats to Rio butterflies include habitat destruction and the use of herbicides. Another big one is the introduction of non-native plants. One perfect example is the Lange’s metalmark in North America. Its only remaining habitat is the Antioch Dunes National Wildlife Refuge in northern California, where this species is still scarce. Studies have shown that the reduction in population resulted from the use of three damaging herbicides and the loss of the land's original sand dunes.
Furthermore, the Lange’s metalmark depends mainly on the naked stemmed buckwheat throughout its entire lifetime. Their eggs are laid on these plants, then larvae eat it after hatching. The larvae then pupate on the naked stemmed buckwheat and continue feeding on its nectar as an adult butterfly. With the sand dunes disappearing, the naked stemmed buckwheat goes with it. Additionally, invasive plant species like the ripgut brome, vetch and yellow starthistle have become a problem because they are overgrown and continuing to replace and reduce the population of naked stemmed buckwheat.
Did You Know?
- Male Rio butterflies have a pair of reduced legs that are not used for walking, whereas females have three sets of legs that are all used for walking.Learn More »
- The pupae of Rio larvae are usually hairy and are attached to a plant, leaf litter or debris on the ground. Though they do pupate, they are not actually encased in a cocoon during metamorphosis.Learn More »
- Only 20 species of Rio butterflies can be found in North America.Learn More »
- About 50 to 100 years ago, there were about 25,000 Lange’s metalmarks in the northern California area. In 1972, its population dropped to 5,000, decreasing to as few as 45 in 2006.Learn More »
- Rio butterflies are known for their weak flight style.Learn More »
|Compare & Contrast||Rio Butterflies||Neotropical Butterflies|
|How many species?||Approximately 1,300||More than 7,800|
|Where do they occur?||Though Rio butterflies are found worldwide, they occur mostly in the neotropics.||In the neotropical region, specifically from Mexico to the southernmost part of South America|
|What do they eat?||Rio larvae have a wide range of foods that they can eat, including plant leaves, flowers, insects and more. Rio butterflies drink flower nectar and have also been seen mud-puddling. Some diets may be more specialized, but many of them are quite broad.||Caterpillars eat the leaves of plants, and butterflies sip juices from fruit, nectar, sap and mud.|
|Do they have predators?||Birds, fish, rodents, frogs, toads, snakes, lizards and large insects||Snakes, frogs, toads, spiders, wasps, ants, rodents and more|