Maternal age and density effects on carbohydrate partitioned to eggs of the grasshopper, Aulocara elliotti

Abstract

Mannose, glucose, glycerol, and trehalose were identified by chromatographic means in 1- to 7-day-old eggs of the grasshopper, Aulocara elliotti. Trehalose and ‘glycogen’ levels, at a time when embryonic development had not progressed beyond the blastoderm stage, were measured in eggs collected from adults reared at three densities throughout the fecund period. Glycogen levels in these eggs increased with maternal age as did egg weight. Parental density had no noticeable effect on glycogen content in eggs. During the last half of the fecund period, trehalose decreased from 57·6 to 20·2 μg/egg (9·46 to 3·21 mg/g fresh egg weight) in eggs obtained from adults reared at the highest density. This is probably due to the combined effect of crowding and maternal age. The greater the density, the greater the amount of trehalose that was partitioned to eggs during the first two-thirds of the reproductive period. Maternal age and density effects on trehalose levels partitioned to eggs are discussed in relation to rate of development and a density-stress response mechanism which may be likened to that of vertebrates.