• K M Alexander

      Articles written in Proceedings – Animal Sciences

    • Feeding behaviour of the Indian musk shrew,Suncus murinus viridescens (Blyth)

      M Balakrishnan K M Alexander

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      A detailed study on aspects of feeding behaviour of the Indian musk shrew,Suncus murinus viridescens, was made. The first solid food intake commenced on the 14th day and weaning occurred on the 20th day after birth. Olfaction was the primary sense involved in food searching. Prey killing was effected by a characteristic neck-bite. Death-shake could be seen when the shrews predate on earthworm or on rodents such as rats. Shrews hoard food when a large number of insects as food was offered. A thorough mastication of the food was observed before swallowing.

    • Effect of fasting on aspects of feeding of the Indian musk shrew,Suncus murinus viridescens (Blyth)

      M Balakrishnan K M Alexander

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      Studies on food deficit drives of the Indian musk shrew,Suncus murinus viridescens, have been made. The time taken by shrews experimentally subjected to definite periods of food deprivation to reach the food steadily decreased upto 4 hr of deficit, and thereafter a zig-zag pattern was discernible. The duration of eating bouts increased after shrews were motivated for food for a period of upto 36 hr. The amount of food intake by shrews steadily increased when subjected to differential food deficit drives upto 12 hr and subsequently declined. No significant sexual dimorphism was observed in the differential food deficit drives inSuncus murinus viridescens.

    • Effect of castration and oral administration of sex hormones on some specialised integumentary glands of the male musk shrew,Suncus murinus viridescens (Blyth)

      M Balakrishnan K M Alexander

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      Effect of castration and oral administration of sex hormones on the specialised apocrine sudoriferous glands of the perineal region and the holocrine sebaceous glands of the flank and oral lip regions of the male musk shrew,Suncus murinus viridescens is investigated. Gonadectomy effected a significant regression and hypotrophy of the sudoriferous as well as sebaceous glandular structures of the shrew. The secretory epithelial cells were depleted and the tubules were devoid of any secretory material at the end of one month of castration. Subsequent administration of methyltestosterone daily for four weeks reactivated all these glands, whereas the gross morphological features of sebaceous glands did not vary at any significant level after treatment with ethinyloestradiol daily for four weeks. However, partial rejuvenation in the cellular structures was noticed in all these glands of shrews orally administered with this heterosexual hormone.

    • A comparative study on certain biochemical aspects of red and white myotomal muscles of the black skipjack tuna,Euthynnus affinis Cantor

      N Gopinathan Pillai K M Alexander

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      The biochemical assay of certain metabolites of the red and white myotomal muscles of the tuna,Euthynnus affims Cantor has been carried out. The metabolites exhibited a marked variation in their distribution pattern in red and white muscles. The narrow red fibres are characterised by higher levels of lipid, glycogen, myoglobin and SDH while the broader white fibres had lesser amount of the above metabolites. The distribution of metabolites—the myoglobin and SDH, revealed a gradientfrom the superficial towards the inner layers of the red myotomal muscle in both the pectoral and middle regions. The physiological relevance of these biochemical variations in diverse regions of the red and white muscle is discussed.

    • Distribution pattern of succinic dehydrogenase in the myocardia of some vertebrates

      Mathew M Oommen K M Alexander

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      A comparative study on the myocardial SDH levels in certain representative vertebrates revealed interesting variations. TheCybium myocardium exhibited relatively lesser SDH levels, whereasRana, despite its diving habits, had a higher level with significant variations between the two ventricular halves.Calotes, an active terrestrial form, showed the highest enzyme level among the reptiles. The SDH activity of the avian myocardia are quite high, withColumba having a greater level thanGallus. The myocardia of the actively flying forms (Columba andPteropus) exhibited higher enzyme levels in the right ventricle than the left ventricle.

    • Specialized integumentary glands of house rat,Rattus rattus

      R Kairali P Rani K M Alexander

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      Specialized integumentary glands have been observed at certain specific body regions of the common house rat,Rattus rattus. Diverse zones such as eyelid, oral angle, prepuce and circum anal possess hypertrophied skin glands. The histophysiological aspects of these integumentary glands are reported. These specialized sebaceous glands have specific behavioural relevance.

    • Observations on the fine structure of the sebaceous flank gland of the Indian musk shrew,Suncus murinus viridescens (Blyth)

      M Balakrishnan K M Alexander J C George

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      The fine structure of the sebaceous gland acini which form the bulk of the flank gland in the Indian musk shrew was studied. The secretion of the gland appeared to be mainly lipoid in nature, seen as numerous intracellular lipid droplets showing varying degrees of osmophilia from light to intense dark. The mitochondria contained one to several electron dense inclusions which were discharged from disrupted mitochondria and were seen floating in the cytoplasm and also in the ducts of the gland complex. It is suggested that these inclusions which presumably contain high concentrations of waxes synthesized within the mitochondria, form the major components of the holocrine secretion discharged from the flank gland of the shrew.

    • Recent advances in animal behaviour

      K M Alexander

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      Ethology, a fast developing field of animal sciences has considerable relevance in animal husbandry, agriculture, control of animal populations, pest control, medicine, wildlife biology, etc. It has made vast strides of progress during the past few decades and some of these trends are reviewed.

      Communication signals play a salient role in sociobiology of animal groups. Animals deploy visual, acoustic, tactile and olfactory signals during their social interactions. Among these, olfactory cues have certain specific advantages over the other modes concerned. Recently considerable attention has been focussed on chemical signals in animals, especially those of economically important forms such as insects, fishes and mammals.

      Regarding insects, sex pheromones, aphrodisiacs, trail markers, aggregating and alerting pheromones have been isolated in various insectan orders. The factors controlling sex pheromone behaviour and impact of pheromones on control of insect population have been elaborated.

      Investigations on chemical cues of lower vertebrates indicate that fishes, amphibians and reptiles deploy them in their social interactions. Pheromones modulate the schooling, reproductive and alarm response behaviour in fishes.

      Among mammals, urine, fecal pellets, saliva and secretions of specialised skin glands function as sources of olfactory cues. Data on histophysiology, and ultrastructure of specialised skin glands, biochemistry of their secretions have been collected. Osmetrichia, scent marking patterns and fiehmen responses and their hormonal control have been elucidated. The neuroendocrinological basis of scent marking has been made explicit.

      Relatively only very few of the mammalian pheromones have been isolated. The role of Primer pheromones in modulation of reproductive processes in some of the rodents and signalling pheromones in social interactions of some mammals have been elaborated.

      Data on olfactory cues in human social interactions indicate the presence of social pheromones.

      Visual signals of some insects and their role in reproductive activities have been investigated. Social postures in some rodent pests and their behavioural relevance have been studied. Acoustic signals in insects facilitate congregation, sexual attraction, aggregation and alarm responses. Further various aspects of vocalisations in birds and mammals have been investigated. Reproductive investment patterns and sex ratios in insects and parental investment in birds have been elucidated. Play behaviour and their role in behavioural development has been investigated. Etiological analysis of drug action in aggressive behaviour in certain mammals has been made.

    • Specialised integumentary glands of the Indian field mouse,Mus booduga booduga

      Latha K Pillai S Santhi K M Alexander

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      Histomorphological investigations on the specialised integumentary glands of Indian field mouse,Mus booduga booduga have revealed the existence of hypertrophied integumentary glands in the eyelids (tarsal), oral angle and at the perineal (circumanal) regions. The histophysiological characteristics of these specialised integumentary glands and their probable behavioural significance are discussed.

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