Studies on the physiology of a shrimp, Metapenaeus sp. (Crustacea: Decapoda: Penaeidae). II. Endocrines and control of moulting

Abstract

Eyestalk ganglionic neurosecretory endocrine glands, the sinus gland, and sensory-pore organ are described and figured. The thoracic gland was found to be a narrow longitudinal strip of epitheloid tissue immediately inside the dorsal cuticle of the anterior branchial chamber. Neurosecretory cells were present in the brain and thoracic ganglia, and post-commissural organs were identified. Moulting was erratic under laboratory conditions and tended to be arrested at an early premoult stage. Moulting could not be induced in intact, nor accelerated in eyestalkless animals by injections of sensory-pore-complex extracts. Ventral glands (Y-organs) and ventral gland extracts from two species of crab donor at different seasons and from eyestalkless donors were also without effect. Eyestalk ablation induced moulting, but the response was relatively slow and erratic. It is concluded that there is little evidence for the existence of a specific moult-accelerating hormone in this species, that morphogenetic hormone is ineffective unless extrinsic factors and nutritional state are optimal, and that moult-inhibiting hormone is largely produced within the eyestalk.