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11

It has been cold and rainy here this week, but we still have plenty of insects. You see, they are all indoors.

Here is the story of our silkworms in photographs:

We bought our caterpillars over the Internet. They arrived in a plastic cup. Look at all the colors!

The caterpillars ate a commercial food made up of dried mulberry leaves and thickeners. We bought some extra food from the supplier, because we weren't sure we could find mulberry leaves. We made it in the microwave by mixing the powder with water and cooking it.

After a few weeks, we did find some mulberry leaves.

The caterpillars ate a lot of mulberry leaves.

The caterpillar makes silk with a gland that exits in its mouth.

When they are ready to pupate, the caterpillars start to make a silk bag around themselves, which is the cocoon. The cocoon is what is used to make the fabric silk.

When we did this before, all the cocoons were white. This time they were white, pale yellow and deep golden yellow. (The colors have to do with the mix of varieties we got.)

After about two weeks (depends on the temperature), the first moths emerged.

This is a male. Isn't he cute?

The females laid eggs on other cocoons and on some cardboard egg cartons we provided.

silkworm-eggs2

The eggs are the size of pinheads or slightly larger. They are light to dark gray in color.

The best part of this project has been sharing the caterpillars and the stories with our friends.

For more information about silkworms, see Silkworms: A Thread through History, and also the link at the end of that post.

Related books (with Affiliate links to Amazon)

Silkworm (Life Cycle of a . . .) by Ron Fridell and Patricia Walsh

Age Range: 6 - 8 years
Publisher: Heinemann; 2nd Edition edition (August 15, 2009)
ISBN-10: 1432925458
ISBN-13: 978-1432925451

The Story of Silk: From Worm Spit to Woven Scarves (Traveling Photographer) by Richard Sobol

Age Range: 6 - 9 years
Publisher: Candlewick (September 25, 2012)
ISBN-10: 0763641650
ISBN-13: 978-0763641658

2

Did you figure out the mystery insect from last week?

The patches of mud you see on the trunk of the saguaro are made by desert encrusting termites (Gnathamitermes sp., probably Gnathamitermes perplexus).

These desert termites build layers of mud on the bases of saguaros or palm trunks. They also plaster mud over dry grass or twigs on the ground, particularly after a rain.  Over time they eat the grasses or twigs, leaving a hollow tube of dried mud.

On trees, they gently scrape the surface clean of dead material.

Desert encrusting termites are different from other termites because they do not enter or eat sound, strong wood. They could even be considered beneficial. Have you ever heard that termites have protozoa in their guts to help them digest the cellulose in wood? Desert encrusting termites have bacteria instead. Those bacteria are capable of fixing nitrogen, which means they actually fertilize the soil. Because the termites work on dry grass and twigs on the ground, they reduce fuel for wildfires. Finally, by tunneling in and moving soil, they aerate it, making it better for plants.

You could say that desert encrusting termites are part of nature's clean up crew.