Chemistry and Biochemistry of Insect Hormones

Insect hormones attracted the interest of endocrinologists only comparatively recently. This is partly due to the fact that an equivalent of sex hormones – the classical hormones of vertebrate physiology – is unknown in insects. Castration has no marked effect on the secondary sexual characters. Insect hormones act primarily on developmental processes; the metamorphosis hormone, ecdysone, is the best studied. Recent investigations have shown that ecdysone has the empirical formula C 27 H 44 O 6 and belongs to the streroids. The mechanism of its action is seen in its influence on the chromosomes. – Other hormone‐like substances, the pheromones, are outstanding for their high activity; a few molecules are sufficient to trigger the characteristic behavioural response.