Thursday, 6 October 2011

Golden Tortoise Beetle

The golden tortoise beetle has a stunning, vibrant metallic gold color.

It has a magical quality, not only because of the brilliance of its color, but also because the brilliance isn't permanent. Metriona can alter color within a short time period, turning from brilliant gold to a dull, spotty reddish color. The gold color also fades when the insect dies. What controls the color while the insect is alive is an intriguing question. The gold color is caused by a thin layer of moisture between the cuticle and an inner layer of the elytra. Apparently the insect is able to "voluntarily" squeeze this layer, reducing its thickness and eliminating the gold color. This change also occurs involuntarily when the beetle is under moisture stress, and, of course, when it dies.

A bit smaller than the more familiar ladybird beetles, the golden tortoise beetle is configured somewhat like a safari hat with a narrow "shelf" skirting the outside of the wing covers and thorax. This "shelf" causes the resemblance to a tortoise, hence the name. Tortoise beetles are plant eaters, like most Chrysomelids [leaf beetles]. The golden tortoise beetle in particular feeds on morning glory. They reside under the leaf, eating a series of small holes resulting in a characteristic damage pattern.

Other types of Tortoise Beetles

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