Juvenile Hormone Activity in Micro-organisms and Plants

Abstract

THE juvenile hormone of insects promotes larval development but prevents metamorphosis. Its presence in an immature insect ensures that when the larva molts it will retain its larval characters and not differentiate into an adult¹. Extracts with juvenile hormone activity were first prepared from the abdomens of male Cecropia moths by Williams². Afterwards active extracts were prepared from adult males and females of 6 families of Lepidoptera as well as from eggs, larvæ and newly moulted pupæ^3,4, from representatives of 6 other orders of insects including Dictyoptera, Orthoptera, Hemiptera, Coleoptera, Diptera and Hymenoptera^4–7 and from various insect products, for example, royal jelly⁷, insect fæces⁸. Investigation of other groups uncovered substances with juvenile hormone activity in extracts of the adrenals of cattle⁹ and in many tissues of numerous invertebrates in 13 classes, including Hydrozoa, Anthozoa, Anopla (Nemertinea), Cheilostomata and Ctenostomata (Ectoprocta), Pelycepoda, Gastropoda, Polychaeta, Oligochaeta, Malacostraca, Arachnida, Holothuroidea and Balanoglossida^6,7. The most active invertebrate sources were the eye-stalks of crustaceans (Homarus and Carcinides)^6,7, and the heads of polychaetes (Nereis)⁷. Juvenile hormone activity was later demonstrated in many vertebrate tissues besides the adrenals including pituitary, kidney and thymus¹⁰ and lymphatic, parathyroid, thyroid, mammary and gastric mucin (Schneiderman, H. A., and Gilbert, L. I., unpublished observations).