The woolly bear caterpillar is only two colors, Rusty brown and black
Other caterpillars (normal caterpillars) can be bright and found in almost any color
This is where the woolly bear caterpillar lives...the Artic
To warm up the woolly bear caterpillar basks in the sun
Here is a time-lapse showing the Woolly bear caterpillar making it's cocoon. |
Introduction:
The Arctic woolly bear caterpillar, also known as the Pyrrharctia Isabella, can be found in Greenland and Canada around the Arctic Circle. They are often sighted by natives during the late fall and early winter. “People see them a lot this time of year, because they’re trying to find a place to spend the winter,” said Linda Williams, DNR Forest Health Specialist. Once they find a place, the caterpillars freeze themselves for a couple months and then thaw out again in the spring to continue eating. This lifestyle is very strange for a caterpillar. The wooly bear caterpillars have adapted to survive to temperatures below -60 °C. To accomplish this, the woolly bear caterpillar must build up enough biomass through eating to turn into a moth. Unlike other caterpillars, they only spend about 5% of their lives eating, usually during the month of June. The rest of their lives are spent frozen and dormant. The woolly bear caterpillar’s life-span is up to 14 years, the longest life-cycle of any butterfly or moth. The Caterpillars produce Anti-freeze During the winter, the Arctic Woolly bear caterpillar freezes and becomes dormant. The caterpillar’s heart almost stops pumping as its body produces an anti-freeze like substance to protect the organs and brain from the devastating cold. This anti-freeze substance is called cryoprotectants. Cryoprotectants are chemicals that dissolve, and lower the melting point of water. The main contents of the anti-freeze are glycerol and sorbitol. How does this caterpillar differ from other caterpillars? Woolly Bear Caterpillar: The Woolly bear caterpillar lives up to 14 years. Although they have a very long life-span, only a short amount of it is spent as an adult caterpillar/moth. Within 24 hours of becoming an adult, the moth lays eggs and dies. Another difference is the habitat of this caterpillar. Since this caterpillar lives in the Artic, it has to freeze itself to survive the long winters. The caterpillars freeze and thaw out about seven times throughout their life. Other Caterpillars: Normal caterpillars usually live about one-two months. These caterpillars lives are very short and after becoming a moth, they lay eggs and die within two-three days. Unlike the Woolly bear caterpillar, most normal caterpillars do not freeze their internal organs to survive the winter. These normal caterpillars can live almost anywhere, and don't have to worry about the fierce winters of the Artic. How has the woolly bear caterpillar adapted to the Artic While you may think that wooly bear caterpillar's love the cold of the Artic, that is not necessarily true. In fact, the Woolly bear caterpillar basks in the sun constantly to warm up - The caterpillars spend up to 60% of their time while active basking. By doing this, the caterpillar can reach a temperature which allows them to feed and grow - about 30°C. This usually occurs around midday, before and after feeding, and when moving to a new location. Another way that the wooly bear caterpillar has adapted is the production of cryoprotectants. The caterpillar uses this anti-freeze substance in the blood and body tissues to keep it's self alive. Since the Woolly bear caterpillar lives in the Artic, it has to produce cryoprotectants to protect itself from the bitter cold of winter. The cryoprotectants help lower the freezing point in their blood which helps to keep the caterpillars brain and tissue safe from damage and harm. Life-cycle Egg-born in the form of an egg Larva-caterpillars feed during the larva stage Pupa-entomb themselves in a silk cocoon Adult/Moth-emerges from the cocoon as a adult/moth Folklore There are many myths about the wooly bear caterpillar. My favorite however, is the myth about its ability to predict the winter weather. Popular folklore claims that the length of the center stripe on a woolly bear predicts the upcoming winter weather. If the black stripes on each end are longer than the middle stripe the winter will be harsh. It also states that if the center stripe is wide that the winter will be mild. However, many scientist believe that the caterpillars stripes have nothing to do with the winter. One scientist said, "The amount of brown on the caterpillar is actually related to the age of the caterpillar. So if we have a really late spring, if they don’t get started until later in the year, they’re going to be younger when fall hits when they’re looking for a place to spend the winter. The younger the caterpillar, the more orange,” said Williams. The accuracy of the caterpillars winter prediction is very difficult for scientists to determine. Among a group of woolly bears, the stripes can be very different, making the winter forecast difficult to interpret. According to Perrie Layton "Perhaps, like TV weathermen, some caterpillars are correct and some are not." |