0000000000400685
AUTHOR
Charles Noirot
Social structure in termite societies
The societies of Isoptera and Hymenoptera differ in two general features. 1. The termite societies are bisexual. From a primitive symmetry between both sexes, many asymmetries appeared during the course of their evolution. These asymmetries are related either to a sexual dimorphism, or a biased sex ratio, or both, and are differently expressed in the separate castes of a given species. 2. The hemimetabolous development allows a termite to take part in the social tasks before the end of its postembryonic development, and even to reproduce at a larval stage (neoteny). Thus Isoptera exhibit a polymorphism of larvae, unlike Hymenoptera where a polymorphism of imagoes is observed. Moreover, an i…
Termite Nests: Architecture, Regulation and Defence
Termite nest architecture evolved along with changes in lifestyle, the basic building behaviour being transmitted through the genes of reproductives. The main selective pressure is thought to have been defence against predators. In more advanced termites the maintenance of homeostasis in temperature and humidity may appear to dominate nest architecture. Nest defence involves nest structures in combination with the morphology and behaviour of the sterile castes. The soldier caste, characteristic of termites, is specialized for defence, with a variety of mechanical and chemical weapons, but this caste was lost in some advanced genera, especially the Apicotermitinae. Workers are always involve…
Caste differentiation in Isoptera: basic features, role of pheromones
The polymorphism of termites, essentially phenotypic, results from alternative orientations during individual development, triggered by hormones and neurohormones. The hormonal equilibrium is itself modulated by several influences, both from the outer world and the society. Among the latter, the primer pheromones seem especially important in the regulation (either by stimulation or inhibition) of the separate castes.
Ecdysone and ecdysterone in physogastric termite queens and eggs of Macrotermes bellicosus and Macrotermes subhyalinus
Abstract Physogastric queens and freshly laid eggs of two species of termites ( Macrotermes bellicosus and Macrotermes subhyalinus ) are found to contain high levels of ecdysteroids (molting hormones) as indicated by radioimmunoassay and Musca bioassay. Ecdysteroids are accumulated in the ovaries of the queen and then stored in the eggs since newly laid eggs contain ecdysteroid concentrations similar to those found in the ovaries. Gas chromatography-mass spectrometry demonstrates that ecdysone (α-ecdysone) as well as ecdysterone (β-ecdysone) are present in queen ovaries and in eggs and that ecdysone is quantitatively the more important ecdysteroid in both ovary and eggs.