Hemolymph juvenile hormone titers and growth of terminal oocytes throughout the first gonadotrophic cycle inAiolopus thalassinus

Abstract

In Aiolopus thalassinus (Fabr.) (Ins.: Orth. :Acrididae) juvenile hormone III OH-Il l ) , is the only homologue detected in the hemolymph [4]. It stimulates synthesis and secretion of vitellogenin in the fat body. This precursor of egg yolk protein is then sequestered and deposited as vitellin by the developing oocytes. All terminal oocytes grow synchronously into eggs. The corpora allata (CA) are the sites of JH synthesis; allatectomy prevents the production of JH in locusts and in grasshoppers, no eggs were formed [1]. Treatment of A. thalassinus females with precocene-III (an antihormone) inhibits the secretion of JH-III , and induces sterility in adult females [4]. In female acridids, CA size and JH hemolymph content increase during the first gonadotrophic cycle [2]; CA activity and reproduction are well correlated, but the CA volume is not always a valid indication for reproductive activity. The biosynthetic activity of the glands is suggested as a good indicator. However, there can be large individual variations in relation to the age of the adult females. Using the GC-MS-MIS technique, Rembold and Lackner [7] quantified the JH contents of different insect length and width of the terminal oocytes were measured; the volume of the terminal oocytes was checked throughout the whole cycle. Table 1 demonstrates a modulation of the JH-I I I hemolymph pool during the first gonadotrophic cycle of A. thalassinus which is very similar to that of L. migratoria as reported by Rembold [6].