Mutagens and toxins

Stressful conditions induced by toxic or mutagenic chemicals may affect insect growth and form to varying degrees, ranging from death at one extreme to slight phenotypic modifications at the other end of the spectrum. Some life-history stages may be more sensitive to mutagens or toxins than others, and phenotypic effects may not be measured easily by crude estimates of stress, such as percentage survival. One measure of the amount of genetic or environmental stress experienced by insects during development is the incidence of fluctuating asymmetry, or the quantitative differences between the left and right sides of each individual in a sample of the population. Insects should be bilaterally symmetrical, with left and right halves of their bodies as mirror images, except for obvious differences in structures such as the genitalia of some male insects. Under stressful (unstable) developmental conditions, the degree of asymmetry tends to increase. However, the underlying developmental genetics is poorly understood, and the technique is unreliable, with doubts having been raised about interpretation, such as variation in asymmetry response between different organ systems measured.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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