Biston Betularia Caterpillar, Photo By Bud Logan
The Adult Biston Betularia Moth moth ( also called the peppered moth ) is great at camouflaging themselves, and they are adept at this in their larval form, too. Peppered moth caterpillars look remarkably like sticks or twigs, which lowers their chances of getting picked off by birds and other potential predators. They’re even able to change their color from brown to green so they match the color of the plants they’re living on.
While many moth larvae are specialized eaters, able to live on only one kind of plant, peppered moth caterpillars are able to eat a variety of plants, such as cottonwood, rose, hawthorn, and alder. This adaptation gives them a greater chance of survival.
Biston Betularia (Peppered Moths) are sometimes called salt and pepper moths, this is because of the black and white markings on the moths. These markings allow this moth to hide in full sight, they like to rest during the day by hiding on trees that have lichen coverings. They become virtually invisible. There are two types of coloring to these moths, now you will most likely see the black and white coloring but in the 1800s during the industrial age, they were mostly black with very little white markings. They are quite common on Vancouver Island.
Before the industrial revolution, the black and white form of these moths were the most widespread. This coloration allowed them to camouflage themselves on tree bark covered in light moss and lichens. As the industrial revolution heated up, cities and the surrounding forests became covered in soot. This made the black coloration a better camouflage on the trees which made them less likely to be eaten by predators. These dark moths very quickly outnumbered the lighter form and thrived. Now that we have better pollution control and the soot from factories is not covering the trees, we have seen a return to the white and black forms. This variation only occurred in industrial areas, outside these areas the moths always have been black and white.