Polygenic Industrial Melanism

Of all categories of melanism, polygenic industrial melanism has been the least considered and is the most difficult to address. Examination of specimens collected over the past century and a half suggests that many species have experienced a gradual darkening of the colors and loss of patterning in industrial regions, irrespective of morph. Although some of this change may be attributed to the gradual fading that occurs in museum specimens with time, it is difficult to ascribe all of the differences to this phenomenon. Comparison of series of specimens of six species, from rural and industrial regions, collected between 1880 and 1914 with those collected between 1992 and 1996 showed that the ground color had darkened more in industrial regions than in the rural areas.

This gradual darkening is probably the result of selection acting on polygenic variation. Small variations in the color patterns of many species are known to be controlled by many genes, each having a small effect. The selective predation of lighter and thus less cryptic forms in regions affected by par-ticulate air pollution will result in those alleles which produce darker morphs increasing in frequency. It is difficult to see how this hypothesis can be tested. However, if it is correct, the recent decrease in pollution should lead to a reversal of this trend, with ground colors lightening and patterns becoming more clearly defined again. Novel, digital methods of measuring the spectral reflectance of surfaces and storing data should allow measurement without reliance on museum specimens or photographs, both of which may fade with time.

Bee Keeping

Bee Keeping

Make money with honey How to be a Beekeeper. Beekeeping can be a fascinating hobby or you can turn it into a lucrative business. The choice is yours. You need to know some basics to help you get started. The equipment needed to be a beekeeper. Where can you find the equipment you need? The best location for the hives. You can't just put bees in any spot. What needs to be considered when picking the location for your bees?

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