Feeding activity, sexual maturation, hormones, and water balance in the female African migratory locust

Abstract

Feeding activity and water content are examined in relation to sexual maturation in allatectomized, allatectomized-ovariectomized, ovariectomized, and operated control females. Operated control females undergo two distinct phases of active feeding: the first occurs shortly after emergence and is independent of the maturation process; the second phase is associated with sexual maturation and is more intense than the first. The two phases are usually separated by a short period of low food consumption. Removal of the corpora allata, or corpora allata and ovaries, prevents the second phase of active feeding, whereas removal of the ovary alone has less effect. Allatectomized and allatectomized-ovariectomized females have a low water content and small blood volume as compared with the operated controls, but ovariectomized females have a high water content and become distended with blood. Ovariectomy also results in a large accumulation of protein in the blood, whereas in allatectomized and allatectomized-ovariectomized females, the blood protein concentration is only slightly higher than in the operated controls. The observations are discussed, in particular the control of feeding activity, and the rôle of the neuroendocrine system in the adult female. It is suggested that the corpora allata are involved directly in the control of protein synthesis, and that in the maturing female the cerebral neurosecretory system is very active in maintaining water balance.