|Isabella Tiger Moth|
|Aliases||Banded Woolly Bear|
|Species Type||Tiger Moth|
|Environment||United States and southern regions of Canada|
|Discoverer||James Edward Smith|
|Reproduction||Sexual; lays eggs|
|Average Length||Instar: 2.09" (52mm)|
|Locomotion||Powered flight, Hexapodal walking|
|Feeding Behavior||Instar: Herbivorous|
|Prey||Instar: Opportunistic generalist (includes herbs & trees)|
|Related Species||Garden Tiger Moth, Grammia incorrupta|
The Isabella Tiger Moths (Pyrrharctia isabella) are a species of tiger moths that is indigenous to the United States and southern regions of Canada. They are generalist feeders during their caterpillar or "woollybear" stage and will feed upon many different plant species that include but are not limited to varieties of herbs and trees.
They are related to both the Garden Tiger Moth and Grammia incorrupta, two other species of woollybear tiger moths which consume alkaloid-laden leaves. In the latter's case, they are known to use this to fight off internal, parasitic fly larvae. This is notable as the first clear demonstration of self-medication among insects. It is unknown of the Isabella Tiger Moth performs a similar procedure, however.
Isabella Tiger Moth woollybears have thirteen segments and are generally covered in setae which is brown (reddish-brown in direct sunlight) in their mid-regions and black at their anterior and posterior ends. This setae is not usually harmful as it is incapable of injecting venom and is not urticant in design; it also cannot cause irritation, inflammation, swelling, or general injury, though it can cause dermatitis due to the sharpness of the spiny 'hairs'. Instead to defend themselves, the woollybears will "play possum by rolling up into a ball and remaining motionless to appear dead before quickly crawling away once the potential predator has lost interest.
Upon reaching their mature imago state, they are generally a dull yellowish to orangish hue with a robust and scaly thorax. Their forelegs are a bright reddish-orange and their wings have sparse black spotting. Their head is small in size.
Isabella Tiger Moths are late bloomers, emerging from their eggs in fall only to overwinter as woollybears. They produce a cryoprotectant in their tissues to survive this procedure as they will literally freeze solid during the cold winter months; this also allows them to survive in arctic regions of the world. During their freeze over, their heart first stops beating, followed by their gut freezing, the blood, and finally the rest of the body. They will thaw out in the spring.