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Wednesday, August 29, 2007

On a Scale of One to Ten

There have been a lot of words posted here about insects. Some of them have been close to rhapsodic, going on and on at length about the cuteness of stink bug nymphs, the cool efficiency of spiders, the beauty of orb weaver webs or butterflies, the mysteries of the insect ways of life and so on. But I have barely touched upon the things that are scales, which on a scale of one to ten of being cute, dignified, beautiful or remotely humanoid are something like a one-and-a-half. Scale insects are bumps on a tree to the casual observer. They are bumps on a tree to the discerning observer as well unless the immatures are at the crawler stage when they leave the safety of the mother's bump. It is this stage that affords scale species the greatest hope of dispersal, whether it's by wind, animals or most likely humans moving infested plants or plant parts. In just a few days, however, the crawler will settle down, begin feeding, and gradually morph into an adult scale with no easily discernible body parts.

This photo is a wax scale, genus Ceroplastes, one of the soft scales of the family Coccidae. The females often reproduce without mating (convenient when you barely move), and the eggs are deposited under the waxy outer covering. This particular scale was found on a Salvia ulignosa plant. She was all alone. I picked her off the stem to take a look, and found what must be eggs underneath. They are dry and red. When I put the scale back on the stem, she clung to it instantly (is there a brain in there, or was that just a reflexive reaction?) I will be looking out for the crawlers' emergence to have a look at them. In a balanced environment, scales are controlled by various predator beetles, lacewings, mites and wasps. If an infestation gets bad enough to harm your plants, horticultural oil spray can be applied during the winter or early spring.

Lacking facial features and commonly recognized body parts, scales have a hard go at being a sympathetic species to humanity; still you have to admire the evolutionary efficiency, common in parasitic species, that has deleted superfluous body parts and functions to focus on the processes of feeding and reproduction.

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