Tuesday, May 29, 2012

silkworms

   Did you know that silkworm larvae have an anal horn? Well, neither did my second graders, but we checked it out under the microscopes today (pics soon to follow). They eat only mulberry leaves (luckily our school nurse, Miss Debbie has mulberry growing at her house) and a lot of them. A  silkworm multiplies it weight 10,000 times from time it is hatched until about 4 weeks later when it has enough energy stored to start spinning its cocoon. 
    The coveted secret of silkworm cultivation began 5000 years ago in China. Sericulture (the production of raw silk by raising silkworms) spread to Korea and later to Japan and southern Asia. During the eleventh century European traders stole several eggs and seeds of the mulberry tree and began rearing silkworms in Europe. Sericulture was introduced into the Southern United States in colonial times, but the climate was not compatible with cultivation.
   Today, researchers use the silkworm to study pheromones and hormones due to their small size and ease of culture. This makes for an interesting class conversation! Today, while checking them out under the microscope, I hear, "Mrs. Lundquist, they are mating!" to which I reply, "No, they are just crawling over each other to get to the mulberry leaf that you took away from them!" So next I hear one say to his neighbor, "No, they only mate as adults, they are just wrestling." This still takes second place to my earlier earthworm hermaphrodite conversation I had with a kindergarten class. I love the little ones!

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