• Volume 92, Issue 2

      March 1983,   pages  87-184

    • Bioecology ofZaniothrips ricini Bhatti (Panchaetothripinae: Terebrantia: Thysanoptera) — A new thrips pest of castor (Ricinus communis: Euphorbiaceae)

      A Mohan Daniel N Suresh Kumar N Bakthavatsalam

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      Studies onZaniothrips ricini relating to sexual and parthenogenetic reproduction, life cycle, soil pupation, effect of RH and temperature on pupation as well as the three types of migration (i) plant to soil (ii) soil to plant (iii) plant to plant and within plants are discussed. Periodicity of infestation on the castor plant as well as the alternative hostsDatura stramonium andCalotropis gigantean have also been highlighted. The roles of the mantid predatorHaldwania lilliputana and the larval parasiteCeranisus menes are also indicated.

    • Reproductive strategies and behavioural attributes in some sporophagous Idolothripinae (Tubulifera: Thysanoptera)

      T N Ananthakrishnan K Dhileepan B Padmanaban

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      An analysis of the behavioural aspects of some sporophagous Idolothripinae in terms of the diversity of reproduction is presented, involving aspects such as oviparity, grades of ovoviviparity and viviparity inTiarothrips subramanii, Elaphrothrips denticollis, andElaphrothrips procer. Reproductive diapause inLoyolaia indica is also reported.

    • Cytochemical changes in the silk gland cells ofPericallia ricini (Lepidoptera: Arctiidae)

      Shubh Narain D N Vishnoi

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      Cytochemical changes involving PAS — positive and metachromatic substances have been studied in the silk gland cells of the moth Pericallia ricini during growth and atrophy. The distinction between the silk-periphery and silk-core on the basis of metachromatic staining has been traced even in the second instar stage for the first time. PAS — reaction differentiates the same in the prepupal stage. The secretion of two silk constituents goes on simultaneously in the gland cells. The conjugation of PAS — positive polysaccharide group to silk protein takes place in the apical cytoplasm of the gland cells. The core silk secretion predominates in the prepupal stage. Reduction in the amount of carbohydrate material in the basal cytoplasm of the silk gland cells from first instar to prepupal stage occurs with their simultaneous concentration in the apical region of the cells. The degree of metachromasia increases progressively in advancing instars.

    • Taxonomic value of torus longitudinalis and valvula cerebelli in four species ofAmblypharyngodon Bleeker (Pisces, Teleostei, Cyprinidae)

      N Babu N Balakrishnan Nair

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      The configuration of valvula cerebelli and torus longitudinalis shows distinct variations at the level where the tractus mesencephalocerebellaris posterior establishes full connection with the granular valvula in the four species ofAmblypharyngodon. The taxonomic value of the configurational variations of mesencephalon of the four species has been discussed.

    • Histochemical distribution of tetrazolium reductases, dehydrogenases and lipids in the follicular wall of normal and atretic follicles in the ovary of the Indian gerbilTatera indica (Muridae: Rodentia)

      V R Parshad S S Guraya

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      The comparison of the histochemical features of the follicular wall in normal and atretic follicles of corresponding stages in the ovaries of Indian gerbilTatera indica revealed conspicuous changes in amount of lipids and activities of NADH- and NADPH tetrazolium reductases, δ5-3β-hydroxysteroid dehydrogenase and 17α-hydroxysteroid dehydrogenase and succinate- and lactate dehydrogenases in the granulosa layers during follicular growth and atresia. The thecal layers showed a progressive increase in their amounts during follicular growth and these enzymes are not affected significantly by atresia. Atresia resulted in increased amounts of lipids in the granulosa cells and decreased activities of succinate- and lactate dehydrogenases and NADH- and NADPH tetrazolium reductases during latter stages of degeneration.

    • Patterns of rodent pest infestation in relation to rainfed and irrigated crop systems in Rajasthan

      Ranjan Advani

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      A field study on the relationship between rodent fauna and crop ecosystem of the Indian Desert and its two main systems was undertaken in 5 villages and 7 dhanis near Jodhpur. Out of twelve rodent species,Meriones hurrianae had a highest relative abundance followed byTatera indica indica, andRattus meltada pallidior. Rodent fauna in the winter irrigated crops and fields was more diversified (11 species) than rainfed summer crops and fields (10 species).M. hurrianae was a predominant species in rainfed crop fields while,T. indica along withM. hurrianae was a codominant species in irrigated winter crops.Rattus gleadowi andVandeleuria oleracea from summer crop fields andMus cervicolor phillipsi in irrigated crop fields, were altogether absent. Relative abundance ofFunambulus pennanti,R. meltada, Mus booduga, Golunda ellioti gujerati andT. indica increased from rainfed to irrigated crop systems, whereas, reverse trend was witnessed forRattus rattus rufescens, M. hurrianae and twoGerbillus spp. (nanus andgleadowi). Occurrence patterns of different rodent species in the crop ecosystem of Indian desert as a whole and in irrigated and rainfed crop systems in particular have been critically discussed keeping in view their ecological, physiological, behavioural and biological patterns.

    • Dietary water balance in a tropical insect

      M R Delvi

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      Dietary water intake of the tropical grasshopperPoecilocerus pictus fedad libitum from hatching to death on the milkweedCalotropis gigantea averaged 85 or 51 g at 26°C and 171 or 78 g at 36°C for a female and male respectively. As much as 54 or 96 g dietary water is lost via faeces by a female at 26 or 36°C; the corresponding values for a male was 37.5 and 36.2 g. A male or female carried at death about 9 or 6% of the respective dietary water absorbed at 26 or 36.°C. Water loss via exuvia amounted to 26 mg in all the series. Due to oviposition 4.8 or 7.4% of the total water absorbed was lost by a female at 26 or 36°C. There exist a very close relationship between the efficiencies of matter assimilation and water absorption. The high dietary water intake and absorption rates reported for the tropical lepidopteranDanaus chrysippus are correlated with the accumulation of water to meet the requirements during the nonfeeding pupal stage.

    • Effects of different ration levels on survival, moulting and food conversion in two freshwater prawns

      R Ponnuchamy S Ravichandra Reddy Katre Shakuntala

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      Effects of different daily rations of the oligochaete wormTubifex tubifex on survival, moulting and food conversion ofMacrobrachium lanchesteri (Palaemonidae) andCaridina weberi (Atyidae) have been described. Moulting is a metabolic necessity for either species and occurs even at the expense of organic reserves of starving prawns. The geometric derivation of the growth-feeding rate relations inM. Lanchesteri indicated that, 88, 162 and 204 mg live food/g live prawn/dav represent the maintenance, optimum and maximum feeding rates respectively. The corresponding values forC. Weberi were 96, 236 and 396 mg. Food availability has a marked influence on the food partitioning and biochemical composition of either species.

    • Reproductive biology of the larvivorous fishMacropodus cupanus (Cuv. and Val.)

      Sheila Susan Jacob N Balakrishnan Nair

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      Investigations on the maturity stages, pattern of distribution of ova in the ovary, growth of the ova to maturity, minimum size at first maturity, sex ratio, growth rate of the ovary, spawning frequency, spawning season and fish-fecundity relationships of the larvivorous fishMacropodus cupanus indicate the extent to which breeding is geared to take maximum advantage of environmental and other factors which afford the greatest opportunity for survival and development of the new generation. The mode of development and growth of the ova reveal that the first maturation is normally delayed till the main period of body growth is over; further, the linear relationships derived between growth rate of the (female) gonads and fish size are a reflection of the symmetry of the gonads. Correlating data on egg size, fecundity and conditions for incubation,M. Cupanus with its high fecundity and rapid development can be said to incline towards ‘r-selection’ on the continuum between ‘k’ and ‘r-selection’. Investigations on spawning frequency and season reveal the protracted spawning season from April to September and the shorter one in January and February. The distinct monsoon spawning peak leading to an increase of its population during this season coincides with the peak incidence of mosquito larvae, indicating the larvivorous potential of the fish.

    • The germ cell types and spermiogenesis in rose-ringed parakeetPsittacula krameri (Scopoli)

      H R Dang S S Guraya

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      By employing haematoxylin-eosin, iron haematoxylin, PAS and Feulgen reaction techniques, a morphological study has been made of spermatogenic cells in sexually matured parakeetPsittacula krameri. Type-A, intermediate and B spermatogonia occur in addition to type Ao (stem spermatogonia). The Ao spermatogonia is the major constituent of the testis during the regression period. Types A and B are further subdivided on the basis of nuclear size and appearance. The leptotene, zygotene, pachytene and diplotene are also differentiated into early and late stages. The spermatocytes at metaphase have also been observed but their number is very few indicating their very short life period. The round spermatids have also been subdivided into two types (i) spermatids with distinct chromatin (ii) spermatids with homogenously stained nuclei. Spermiogenesis has been subdivided into seventeen stages. The study will serve as a fundamental tool in establishing the correlation between gonadotrophins and seasonal reproductive cyclicity of the parakeets.

    • Synchronous development of the ovary and the female accessory sex glands of a crustacean,Squilla holoschista

      M Deecaraman T Subramoniam

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      Based on the histology of the female accessory sex glands (cement glands) and the sequential appearance of their secretory products, four stages have been distinguished in the development of the cement glands inS. Holoschista. This paper describes the various stages in ovarian development and correlates them to the cement glands activity. A further correlation between the ovarian and cement glands activity has been shown by statistical analyses. A possible endocrine mechanism regulating the synchronous activity of the ovary and cement glands is proposed.

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