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silk worm ?

silk worm ?
Pleasanton / Sunol, Alameda County, California, USA
April 1, 2008
Size: 3/4 "
This little guy was found hanging by a thread of silk dangling from a big Oak tree . I was surprised to see that the strand came from his / her head and not the other end . What kind of caterpillar is this ? It was a windy day and he was spinning when I took this photo , but I was happy with the artistic result with the dappled tree and sky for background . I really am curious ... do all caterpillars make silk ? Is there such thing as a silk worm ? Is this a silk worm ? Thanks for any input , sincerely Bugsys posy


Almost every caterpillar -
Makes what people call "silk," but most of it is to broken and fragile to actually be used for silk. This one is a Geometer (inchworm) moth larva, have no clue what kind though.

I don't know if every single species spins silk, but the ability to do so is found throughout the order Lepidoptera. Many species only do so as an emergency means of escape/safety line (possibly what happened here), or only when they pupate, so you may never see one doing it- but they can.

As for where the silk comes from: spiders have silk-producing organs on their abdomens called spinnerets, but caterpillars spin silk from the other end, and there's even an order of insects called webspinners that spins silk from their front legs (they look sort of like Popeye because of the bulky silk glands there).

Although there are other moths that can be used to make silk, the true silkworm is the larva of a moth that was domesticated in Asia, Bombax mori. They're totally dependant on humans for survival, since they can't even fly. Silk is made by unraveling the cocoons they spin around their pupae.

You might get away with calling some of the secondary silk-producing species silkworms, but strictly speaking the term is reserved for Bombax mori, which wouldn't be found in the wild and only feeds on mulberries- so this isn't a silkmoth

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