• D Muraleedharan

      Articles written in Proceedings – Animal Sciences

    • Endocrine influence on protein synthesis in the fatbodies of female red cotton bug,Dysdercus cingulatus Fabr

      Raji Raghavan D Muraleedharan

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      Extirpation of pars intercerebralis neurosecretory cells (PINSC) of femaleD. cingulatus significantly brought down the level of protein synthesis in the fatbodies 48, 72, and 96 hr after the operation, while implantation of active PINSC into both normal and PINSCablated females elevated substantially the protein content in the fatbodies. Additional supply of JHa (FME) by topical application activated protein synthesis in the fatbodies both in the allatectomised and normal females. Histochemical studies to demonstrate the protein content in the fatbodies of the above experimental insects also corroborated these findings. Probable regulatory mechanism of protein synthesis in the fatbodies of femaleD. cingulatus by the hormonal principles from PINSC and corpus allatum are discussed in the light of the above findings.

    • Hormonal rhythm and behavioural trends in insects

      D Muraleedharan

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      Circadian rhythmicity in the timing of secretion and release of many of the neurohormones appears to be a common phenomenon in insects. Involvement of hormonal components in the locomotor activity rhythm in cockroaches, crickets etc. has not yet been proved unequivocally eventhough some of the findings along these lines support this. Many of the physiological events in insects occur only once in each individual’s life-time-gated events. Release of eclosion hormone in insects is determined both by a circadian clock and by the developmental competence of the insect. Periodic release ofPTTH which influence the moulting process in larvae has been established to be gated. Induction of prodromal signs of pupation as a result of gated release of PTTH in some insects have been confirmed. Intrinsic neurosecretory cells of cc release a hormone (calling hormone) in a rhythmic fashion which affect the pheromone release and subsequent initiation of calling behaviour in some of the lepidopteran virgin females. Production of proctodone by the epithelial cells of hindgut also follows a rhythm bringing about diapause in some of the insects.

    • Assessment of neuroendocrine mechanisms of feeding and reproduction in phytophagous insects

      D Muraleedharan

      More Details Abstract Fulltext PDF

      In acridids during feeding, the central nervous system receives information through sensilla which in turn integrated incoming information giving the appropriate motor output. Hormones and haemolyph factors like osmotic pressure also limit meal size. In the red cotton bug,Dysdercus cingulatus hormones from the neurosecretory cells of the brain induced feeding and the protein food ingested in turn stimulated midgut enzyme production while juvenile hormone has little influence either on feeding or enzyme production. In lepidopterans both brain hormone and juvenile hormone seemed to stimulate feeding and the amount of food ingested induced enzyme production. Midgut endocrine cells have also been demonstrated in several lepidopteran species.

      Reproduction involving vitellogenesis, spermatogenesis, oviposition, accessory glands activity and mating behaviour is also under the regulatory control of several hormonal principles such as juvenile hormone, ecdysone, oostatic hormone etc. However, a detailed analysis of the literature available on the topic reveals that these regulatory mechanisms are tissue and species dependent.

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