Word of the day: Sericulture

(Who am I kidding, these words aren’t random. I pick words that relate to Lepidoptera – from the Torre-Bueno Glossary of Entomology)

Sericulture, commercial raising of silkworms, Bombyx mori, for their silk.

There are many direct and indirect ways that insects benefit our lives. Silk is one of them – that amazingly textured fabric is the product of the domesticated “silkworm”, not a worm but a caterpillar. Sericulture refers to how the caterpillars are raised and farmed for their silk.

Why do caterpillars produce silk, anyway? And how?

Caterpillars have a pair of spinnerets behind their mandibles, which are connected to silk glands. Caterpillars produce silk for a variety of reasons – safety lines, shelters, ballooning, molting mats, cocoons, decorating themselves, and probably more! If you ever see a caterpillar suspended in mid air, it is connected to the tree above from a line of silk. If you watch carefully, you might observe it rolling the silk into a little ball as it pulls itself back up. Some caterpillars will lay down silk wherever they go, so they will never drop too far from their host plant.

When caterpillars are in their first couple of instars and quite small, they may use silk for ballooning. Spiders do this too – releasing some silk fibers into the wind, they can be blown to a new locality. This is helpful if you have a hundred hungry siblings to compete with.

Shelters can be made by silking together two leaves. Molting mats are a layer of silk that a caterpillar can hook its crochets into in order to pull out of its old skin. Cocoons are an enclosure made by some moths to protect their pupa, often made of silk and hairs. And some caterpillars will try to blend in by attaching bits of plant matter to their bodies with silk.

Humans have been taking advantage of the silk production of B. mori for about 5,000 years now. Interestingly, the species no longer exists in the wild, and is perpetuated only for the silk trade and for scientific research. The silk is obtained from the cocoon, which is made of one long strand. The pupa is then discarded or eaten. Yum!

 

Here is an awesome blog with pictures illustrating the whole process.

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Posted on June 25, 2012, in Invertebrates, Lepidoptera, Word of the day. Bookmark the permalink. 6 Comments.

  1. You tell us all about sericulture, and you provide us with an amazing wealth of information, and what ends up going through my mind?

    “Molting mats are a layer of silk that a caterpillar can hook its crochets into…”

    I know, I know… I’m easily distracted. My question, though, upon reading this statement is one that very few people would actually know the answer to, but that someone who studies caterpillars *might*:

    Did the name for the art of crochet (as in with yarn) come about because of that part of a caterpillar’s anatomy, or vice-versa?

    • I have wondered the same thing! Since “crochet” is French for hook, it applies to both the craft and the caterpillar claws. I’m not sure which came first. It can get confusing sometimes but it helps we usually pronounce them differently (for caterpillars, we tend to pronounce the “t” at the end so it sounds like “cro-shettes”)

      • Ahhhh, excellent! The pronunciation change makes a huge difference! I can guarantee that if you hadn’t told me, I would’ve pronounced it improperly. Thanks!!!

      • I can’t guarantee that’s how everyone says it, lots of those sorts of pronunciations vary between labs or regions. But it helps when I regularly talk about both subjects, to distinguish them!

  2. Ah, wandering down my alley, here! I know this is from nearly a year ago; please forgive me commenting on something from so far back.

    I see the “Bombyx mori no longer exists in the wild” mentioned a lot. The Pekingese dog doesn’t exist in the wild, either – they’re both human-selected, fully-domesticated animals. B. mori was selected from B. mandarina, which still exists in the wild in much of Asia, and is considered a pest on mulberry plantations – they not only eat the leaves that are being raised to feed B. mori, but they can also support many of the same diseases and parasitoids that plague the domesticated version. The cocoons are small, typically beige or yellowish, and the moths, especially the males, are vigorous fliers. Where the B. mori have had all their defenses bred out, B. mandarina larvae look like insect droppings in younger instars, and have *amazing* branch-like camouflage in the older instars. You can see some of the markings in their vestigial forms in the B. mori caterpillars, but in B. mandarina, they have everything from leaf scars to bark spotting. They can also do the climbing-up-the-line trick that you mention – while B. mori will either drop, or just dangle. They can interbreed with B. mori, although B. mori has suffered some chromosomal rearrangement in domestication.

  3. Sweet blog! I found it while surfing around on Yahoo News.
    Do you have any tips on how to get listed in Yahoo News?
    I’ve been trying for a while but I never seem to get there!

    Many thanks

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