The Giant Leopard Moth

One of my goals this past year has been to learn more about my local moth population. It's been challenging since I'm much more likely to find them in their larval stage than their adult stage as most are nocturnal as adults. The giant leopard moth is one of the few that I have been able to photograph both as a caterpillar and adult.

In the Fall we typically see a lot of the woolly and bristly looking caterpillars. This weekend while clearing up a bit of leaf litter around the HVAC unit I came across this almost 3" long black caterpillar. It has thick, sharply pointed bristles that glimmered when the sun hit them.

Giant Leopard Moth caterpillar

At first glance it might resemble the familiar woolly bear caterpillar, who is often credited for predicting our winter weather, but upon closer inspection you can see there is a hint of color underneath the bristles which differentiates it from other caterpillars in this family. The stiff bristles are the caterpillar's physical protection and as a rule it is best not to handle hairy caterpillars since the specialized hairs can break off and release a strong toxin which may result in a rash in some people. Some woolly caterpillars can be touched without incident but it is better safe than sorry. The giant leopard moth looks dangerous but it is O.K. to touch.

These caterpillars are reclusive by day and are usually encountered when cleaning up the garden. If you disturb this caterpillar as I accidentally did, it will roll up and in doing so expose its red intersegmental rings. These bold markings are another way this caterpillars warns its predators that it is chemically protected. But even with all this protection these caterpillars are frequently attacked by a tachinid flies.

Giant Leopard moth showing red intersegmental rings

These caterpillars emerge at night to feed on an array of forbs and woody plants including cherry, dandelion, oak, plantain, banana, cabbage, sunflower, violet and willow. They are also known to eat Japanese honeysuckle which is a good thing in controlling this invasive species. But ultimately there are not enough caterpillars foraging on the plant to kill it and we are working our hardest to remove this invasive species from our garden.

One morning this summer I found one of these caterpillars feeding on the squash leaves in our kitchen garden. Looks like it got caught out in the rain.

Giant Leopard Moth caterpillar foraging on squash

The caterpillars you see in the Fall will probably be overwintering under logs and beneath bark and dense leaf litter and studies have shown that the caterpillars can survive freezing temperatures. The moths will then emerge in the Spring.

Now if you think the caterpillar is impressive take a look at the adult. It is even more stunning!

Giant Leopard Moth adult stage

The giant leopard moth is distinctively marked with black circles on pure white wings. The  pattern which resembles a snow leopard covers the moth's wings and head so at rest it is difficult to see where the wings end and the body begins. Look closer and you will see some gorgeous blue-green, metallic accents which are spectacular! The abdomen which is hidden by the wings when at rest also has some bright orange markings.

Giant Leopard Moth showing metallic accents

Like many moths, the female giant leopard moth produces pheromones from a glad at the tip of her abdomen. These potent chemicals carry on the wind and are detected by the male's antennae. The male then follows the scent to his prospective mate. The female lays her eggs on host plants which hatch within a few days. Mating and egg laying occurs at night and the adult moth spends its short life repoducing and does not eat.

As you would expect from moths they are mostly nocturnal using the moon to navigate but are often seen at lights during evening hours because they are not adapted to artificial lights and get confused. In the case of the giant leopard moth it is usually the males who are found at lights. (Maybe that is because the females are busily laying eggs.)