|Walnut Sphinx Moth - REK|
The female moth emerges from its cocoon and spreads its wings to dry. It also spreads its pheromone over the air to attract a male. Once fertilized she will fly off to lay 200-300 eggs on an appropriate food plant. Her caterpillars will eat the leaves of a variety of trees including butternut, hazelnut, hickory, hop-hornbeam, and of course, walnuts. Like the giant silk moths, they have no intestine and live less than a week.
|Walnut sphinx caterpillar with its horn - MJ Hatfield CC|
|Parasitoid cocoons on a dead walnut sphinx moth caterpillar - REK|
"Most life histories involve parasitizing hosts as diverse as aphids, bark beetles, and foliage-feeding caterpillars. Many species are egg-larval parasitoids, laying eggs within host eggs and then not developing until the host is in the larval stage. Unlike ichneumon wasps, many pupate in silken cocoons outside the body of the host and others spin cocoons entirely apart from the host.(3) Also unlike ichneumonid wasps, very few braconids use host pupae to complete their life cycles, except for fly parasitoids in Alysiinae and Opiinae." from Bugguide
|Empty cocoons - click to enlarge|
The sphinx moth itself is a cool creature which is able to whistle at a high pitch, out of our hearing range but heard by birds. We wrote a blog about this some years back. The sound comes out of the most distal spiracle and I wonder if that may be why it holds its rear end up. On the other hand, it may just be showing off.