• Volume 92, Issue 4

      July 1983,   pages  277-342

    • Biochemical correlates of the mechanism of salt uptake and excretion in the gills of freshwater field crab on adaptation to higher salinity

      M V V Subramanyam R V Krishnamoorthy

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      Male adult paddy field crabs (Oziotelphusa senex senex) were adapted to salinity of 34%. After 3 months the gill lamella of the crab was sectioned and examined under an electron microscope and compared with that of freshwater crabs. The apical region nearest to cuticular boundary showed numerous foldings projecting into the cytoplasm of the epithelium. This brush border appearance disappeared in salinity-adapted crabs. Mitochondria also reduced in number in the sections of salinity adapted crabs. In seawater medium the crabs showed a hypo-osmotic regulation. This regulation is said to be involved in active sodium excretion through gills, in contrast to the active Na+ uptake found in freshwater crabs. The ultrastructural changes have been correlated with significant reduction in cholesterol and phospholipid molar ratios of the gill as well as Na+ + K+ ATPase and divalent ion ATPase activities of particulate system of the crab. The univalent ion ATPase activity served as a marker to show the reduced uptake of Na+ on adaptation to higher salinity. The reduced Ca2+ ATPase activity in the gills of seawater adapted crabs has been correlated with the reduced phospholipid content of the gill tissue.

    • Patterns of fungal resource utilization and feeding range in some mycophagous Tubulifera (Insecta: Thysanoptera)

      T N Ananthakrishnan G Suresh

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      Adaptive specialization in terms of survival due to diverse fungal feeding preferences and seasonal dispersal is indicated in the sporophagous speciesLoyolaia indica (Anan). Feeding behavioural patterns of six species of mycophagous Tubulifera reflect diversity in fungal resource utilization and feeding range. Influence of fungal food on the strategies of survival, reproduction and aggregation has been discussed.

    • Ammonia and urea excretion in three species of air-breathing fish subjected to aerial exposure

      M Ramaswamy T Gopalakrishna Reddy

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      Proportions and rates of excretion of ammonia and urea and their levels in blood and liver were determined in two obligate (Anabas scandens andChanna gachua) and one facultative (Mystus vittatus) air-breathing teleosts.A. Scandens andC. Gachua, when exposed to air and returned to water, showed marked increase in the proportions of excretion of ammonia N and urea N, the increase in the rate of excretion of urea N being much greater. Significantly high urea N levels in blood and liver were noticed in both species following emersion. Extra synthesis of urea and marked shift towards ureotelism seem probable in exposedA. Scandens andC. Gachua. No such adaptive shift was observed inM. Vittatus. Ability to survive for longer periods out of water byA scandens andC. Gachua may be attributed to this adaptive shift besides other physiological adaptations.

    • Seasonal variation in the dimension of scent-marking gland of three desert rodents and its possible relationship with their reproductive performance

      Saroj Kumar Ishwar Prakash

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      The two gerbils,Tatera indica andMeriones hurrianae, and the metad,Rattus meltada pallidior exhibit significant monthly variations in the dimension (maximum length X maximum breadth) of the ventral scent marking gland. Peaks in gland size occur late in winter and monsoon which generally correspond to the maximum breeding activity of these rodents during the year. However, the monthly averages of gland area and incidence of pregnancy in the three species do not follow the same trend. It is difficult, therefore, to conclude if the scent-marking behaviour and the breeding performance of the rodents are inter-related.

    • Utilization of dietary protein, fat and carbohydrate by the paddy field fish (Macropodus cupanus: Anabantidae)

      S Mathavan M S M Christopher

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      Preferential utilization of protein, fat and carbohydrate by different weight classes ofMacropodus cupanus was studied exposing the fish to algal, animal and combined feed. Consumption and conversion of protein and fat was maximum in the liver fed group. At maximum feeding the small fish converted carbohydrate, fat and protein at an efficiency of 9.45, 26.55 and 18.29% respectively. The efficiency of conversion decreased with increasing body weight. At all feeding schedules carbohydrate was converted more or less efficiently. The fish exposed to minimum animal feed or 100% algal feed utilized almost equal amount of stored protein cr fat for maintenance metabolism.

    • Energetics of earthworm populations in tropical pastures from India

      B K Senapati M C Dash

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      This paper reports our results of studies connected with the energy flow in earthworm populations in an upland and a lowland pasture where grazing by large herbivores were not allowed. The net annual energy input was more than double in the lowand pasture. Flooding during the rainy season caused heavy mortality and migration of worms in lowland pasture. Higher energy consumption through respiration in the upland pasture was due to difference in environmental conditions. Lower amount of secondary production (P) and higher amount of energy utilized in respiration (R) cause an increased R:P ratio in upland pasture. Energy channelization in both the sites has been represented in box type energy flow models. Management of these pasture lands depends on the understanding of the dynamics of energy flow in these systems.

    • Effect of tranquillisers on the reproduction of a freshwater leech,Poecilobdella viridis (Blanchard)

      A Bhasker Rao C S K Anand G K Kulkarni

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      Effects of two well-known tranquillisers, reserpine and chlorpromazine on the reproduction ofP. viridis were investigated. There was a significant decrease on the ovarian index after reserpine (RSP) injection, whereas, chlorpromazine (CPZ) did not induce any change. But chlorpromazine has a profound effect on the testis index. Surprisingly, injection of the mixture ofRSP+CPZ induced a significant decrease in the ovarian and testis indices. Besides gonad index, the tranquillizer effect on histological profile of gonads was also studied.

    • Wing microsculpturing in the small house cockroach,Supella longipalpa (Dictyoptera, Biattidae)

      M L Roonwal N S Rathore

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      Elytra and wings ofSupella longipalpa (Fabricius) show sexual dimorphism in size, being well developed in males and less so in females. The following eight types of microscuipturing elements (including hairs) occur on both the upper and lower surfaces, varying in size (0.5–100 μm) and density (a few to 1000/mm2): Pimpules, papilllae, rods, microsetae, hairs (setae or macrotrichia of authors), polygons, parallel ridges and an irregular reticulum. The nomenclature adopted is mainly based on termites where these structures have been studied in great detail. Comparison is made with the Isoptera, Embioptera and Zoraptera. The biological and ecological consequences of microscuipturing are discussed.

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