Volume 95, Issue 2
April 1986, pages 117-288
pp 117-124 April 1986
Diversity, density and distribution of the sensilla ofCyrtacanthacris ranacea Stoll during post-embryonic development and their role in feeding are discussed alongside with the scanning electron microscopic studies of these sensilla.
pp 125-134 April 1986
Total zooplankton biomass and the constituent species under the major taxa in relation to hydrographic conditions in the Hooghly estuarine complex were studied around Sagar Island during March 1979 to February 1981. Higher numerical counts and biomass of zooplankton occurred during high saline premonsoon period. During monsoon efflux most of the stenohaline organisms disappeard and only the low salinity species alongwith the euryhaline ones were able to thrive in the estuary. Copepods constituted the most predominant portion of zooplankton biomass throughout the year. Two peaks of zooplankton were invariably noticed—primary major peak during June/July and January/February showed the secondary major peak.
pp 135-145 April 1986
Male largid bugs,Physopelta schlanbuschi, having 2n=17 chromosomes (12 autosomes +2m+X1X2Y), were irradiated with x-ray doees of 300 r, 400 r and 500 r which yielded various types of chromosome aberrations in different stages of meiosis of which the common forms were breaks, fragment of unknown origin, constriction, gap etc. Among the 3 sex chromosomes, the two conspicuously large markers, X1 and Y, sometimes formed chiasmalike configuration in prophase I and metaphase I, while a number of anaphase I plates had a chromatid bridge, very likely formed by the X1 and the Y. The qualitative and quantitative assessments of chromosome aberrations in spermatogonial metaphase, prophase I, metaphase I, anaphase I and metaphase II were made at 13 intervals for the doses of 300 r and 400 r and 14 intervals for 500 r between 5 min and 1 week or more. The data showed over-all dose-dependent aberration effects and the sex chromosomes appeared relatively more vulnerable than the autosomes to different doses of x-rays. The testes of untreated males taken as controls had practically no aberration.
pp 147-153 April 1986
DNA content and effect of diflubenzuron was studied colorimetrically in developing pupae ofCorcyra cephalonica Stainton. The DNA content in developing pupa followed a unique U-shaped curve. Diflubenzuron has no effect on DNA content in the pupae ofCorcyra cephalonica.
pp 155-161 April 1986
Freshwater fishHeteropneustes fossilis andSarotherodon mossambicus were exposed to distillery and paper mill effluents with a view to check the hematological changes as a function of feeding/starvation and aeration/non-aeration. Increase in concentration always produced elevated values in RBCs irrespective of feeding and/or aeration. This elevation was statistically significant (P<0·05) in most of the test individuals. Fish exposed to effluents showed a dose dependent increase in WBCs (P<0·05). Maximum number of RBCs and WBCs was always noticed in the non-aerated condition. Statistical analyses confirmed that the change in number of blood cells as a function of feeding/starvation and aeration/non-aeration was not significant (P>0·05).
pp 163-170 April 1986
Daphnia similis Claus is a tropicopolitan and dominant species of temporary ponds of South India Laboratory cultures were made to study the longevity, preadult instars, egg production and growth using different concentrations of rice bran, an agro-industrial waste which is available readily and cheaply. Rice bran dissolved in pond water resulted not only in higher fecundity but also in an additional increase in size and as such rice bran may form an ideal nutrient medium for mass production of daphnids. Egg production is 6 times higher and growth is two fold greater in cultures with rice bran in pond water than in tap water with rice bran. From the present study it is hoped that, the use of rice bran in mass culture ofDaphnia similis will be profitable.
pp 171-179 April 1986
Histochemical characterisation of ooplasm and yolk granules in different stages of oocyte maturation in the ovary was made in the freshwater fairy shrimpStreptocephalus dichotomus. In stage I oocyte, the ooplasm is reactive to basic and acidic groups of protein, aromatic groups such as tryptophenyl and tyrosyl and sulphur containing substances. The other organic compounds include acid mucopolysaccharide and acidic lipids. In stage II oocyte, sudanophilic lipoidal substances appear coinciding with yolk formation. Stage III oocytes are characterised by the abundance of yolk granules which are rich in sulphated acid mucopolysaccharide as well as glycogen. Besides these, the presence of acid phosphatase activity in the ooplasm and nurse cell is also noticed and its functional role in relation to vitellogenesis is discussed.
pp 181-186 April 1986
The aphid,Cavariella aegopodii is a holocyclic species, alternating between willow and plants of the family Umbelliferae. Its biology and natural enemies are discussed. Morphometry of different morphs are also provided here.
pp 187-190 April 1986
The length-weight relationship ofXenentodon cancila (Ham.) was calculated for males and females. A total of 416 females and 141 males ranging from 101–230 mm in total length was used for the study. Results showed that there is a close relationship between the length and weight of fish. Significant difference was found between the regression coefficients of males and females ofXenentodon cancila. By testing the regression coefficients against the isometric growth values of 3, it was seen that for both males and females, the growth pattern agrees with the isometric growth formula.
pp 191-197 April 1986
The wings and wing-microsculpturing, hitherto either unknown or poorly known, in the small, rare family Indotermitidae, is described here in imagoes ofIndotermes rongrensis. Wings are transparent, colourless and weakly hairy; wing venation is described. Microsculpturing on wings consists of a row of small, pointed papillae at the anterior margin and a dense carpet (3100–3800/mm2) of minute (1–6 μm) simple, nonasteroid micrasters on both the membranes. The phylogeny of the Indotermitidae is discussed. It arose as a lone branch (with 3-segmented tarsi) from the initially 4-segmented ancient Termitidae stock.
pp 199-204 April 1986
Inter and intra specific competition experiments involving 6 taxonomically closely related forms ofDrosophila have been made. Relative fitness and adaptedness of these forms have shown different levels indicating a lack of correlation between taxonomic proximity and ecological phenotype.
pp 205-214 April 1986
Enzyme system pertaining to the midgut region ofAdoretus lasiopyous Burm. is studied in vitro. Most of the carbohydrases operate optimally in the mesomesenteron whereas proteinases and lipases behave optimally in the metamesenteron region. Optimum conditions of certain carbohydrases in relation to pH, temperature, substrate concentration and enzyme concentration have been studied. α-amylase, α-glucosidase, β-glucosidase, α-galactosidase and β-galactosidase showed optimum activity at pH 5·7, 6·2, 5·0, 5·8 and 5·6 respectively, α-Amylase, α-glucosidase and α-galactosidase are physiologically adapted to high temperature ranging between 48°–62°C. A positive response of starvation on the secretion of cellulase, inulinase, α-and β-galactosidase is observed. Based on this parameter the midgut enzymes of the pest is divided into two groups i.e. enzymes secreted continually and those secreted under the influence of food.
pp 215-222 April 1986
Oxygen consumption, carbon dioxide output, nitrogen excretion, respiratory quotient, ammonia quotient and nitrogen quotient in cichlid fish,Oreochromis mossambicus (Peters) acclimated to and tested in freshwater at 30°C, were obtained with special reference to swimming speed (20–77 cm/sec). Tilapia continuously swimming for 5 hr derived energy both from aerobic and anaerobic sources during the initial phase of exercise, whereas during the later phase the energy utilization is completely from aerobic source, as it is evident from respiratory quotient values. It also utilized more proteins for energy during the later phase of exercise, as evident from the increased ammonia-N as well as total N excretion and the respective quotients. The increased protein utilization may be of advantage in maintaining acid-base balance and also in conserving (Na+) in fish.
pp 223-226 April 1986
Administration of vitamin C to juvenile castrated pigeons leads to a fall in the adrenal epinephrine level, but no significant change in the norepinephrine level is noted. Since the role of vitamin C in converting dopamine to norepinephrine is anticipated, it has been surmised that the bursa of Fabricius (thymolymphatic organ) might be responsible for the inability of these young birds to respond to vitamin C treatment.
pp 227-236 April 1986
Intensive host range studies comprising of 55 common weeds and eight cultivated plant species indicated thatNephotettix virescens could survive and breed only on susceptible rice variety, whileN. nigropictus had a wider host range consisting of rice, sugarcane and five graminaceous weeds.N. virescens preferred rice plant both for settling and egg laying whileN. nigropictus showed greater preference toLeersia hexandra than others. Both species selected the host plants by gustation rather than by vision or olfaction.
pp 237-246 April 1986
The harpactorine eggs, laid in clusters and covered by spumaline secretions, are distinguished from the eggs of other reduviid subfamilies by the elaborate net-work-like chorionic collar extensions and opercular outgrowths. The collar extensions may be short with spongy structure, or considerably long with honeycomb structure terminating in filamentous apices. The body of the egg has prominent follicular markings and the anterior end is marked by a distinct collar having the spermatic groove, aero-micropylar openings and the sealing bar. The chorionic collar extensions and the opercular outgrowths, along with the aero-micropylar systems and the inner aerostatic layer, efficiently transport atmospheric oxygen to the interior of the eggs. The ultrastructure of the chorion, the operculum and the aero-micropylar system of 5 species of harpactorine bugs from Southern India is reported.
pp 247-254 April 1986
The longevity ofDaphnia similis Claus is more in pond water (57 days) than in modified Banta’s medium (38 days) and the preadult instar number varied from 3–5,Daphnia cephalata King, however shows no variation in longevity or preadult instar number when cultured in both the media. The rate of egg production of both the species were higher in modified Banta’s medium than in pond water. The differences in the mean number of eggs per instar ofDaphnia similis andDaphnia cephalata in two different culture media are statistically significant (P<0·005;Anova). The variation in growth at each instar forDaphnia similis under two different culture media are statistically significant (P<0·005;Anova) but forDaphnia cephalata it is not significant.
pp 255-262 April 1986
Electrophoretic analysis of the lactate dehydrogenase isozyme patterns of several tissues ofHeteropneustes fossilis andClarias batrachus indicated that in addition to the LDH A and B genes found in these species the liver tissue ofClarias batrachus also possesses a liver specific LDHC. gene.
The relative mobilities of the LDH-B4 and-A4 isozymes inHeteropneustes fossilis andClarias batrachus, are reversed. Further there are significant quantitative differences in the amounts of specific isozymes in homologous tissues of these two species and also in different tissues of a single species as documented in densitomeric tracings. The subunit composition of the LDH isozymes were confirmed by immunological procedures.
pp 263-268 April 1986
In the present study the effect of petroleum ether extract of carrot seeds and progesterone on implantation have been investigated. 0·6 ml/100 g body weight of carrot seed extract was administered subcutaneously from days 1–7 of pregnancy and laparatomized on day 8. No implantation sites were observed. Thereafter graded doses of progesterone 2, 4 or 8 mg/100 g body weight was administered upto day 15 and autopsied on day 16. Two mg of progesterone did not show any effect. However, 4 mg of progesterone treated rats had smaller implantation sites compared to the controls whereas, 8 mg of progesterone was most effective with the result that in almost all the rats, delayed implantation was observed.
pp 269-278 April 1986
Reproductive behaviour inLittorina scabra (Linne 1758) was studied from Porto Novo jetty area and observations were made both in natural habitat and laboratory condition. Copulation was observed throughout the year whenever moisture was abundant. It lasts usually 30–50 min and pairs remain together for several hours after copulation has been completed. Copulation was correlated with lunar phase. Breeding inLittorina scabra was observed throughout the year and spawning occurs during high tide of the newmoon and fullmoon. It is concluded that the breeding cycle completes within two weeks. There is no correlation between the number of offspring and the size of the individual. The first indication of sex cells appear in males and females at the size of 9·02 mm and 8·7 mm respectively. This result indicates that male matures before females. Sex-ratio ofLittorina scabra was 1∶1·44 which showed fluctuation when considered month-wise. Mean shell height of male and female were equal. The development was normal in the salinity ranges of 28–30% and at the temperature of 30°C. The veliger emerged out of the egg at 96 hr after the cleavage has started.
pp 279-288 April 1986
Catfishes of the family Ariidae are commercially important and are represented in Indian waters by 22 species under 5 genera:Arius Valenciennes (18),Osteogeneiosus Bleeker (1),Hemipimelodus Bleeker (1),Batrachocephalus Bleeker (1) andKetengus Bleeker (1). On the basis of certain osteological and morphological characters of the genera, the interrelationships of the Indian genera have been delineated. It is adduced that the Indian Ariidae have had two phyletic lines of evolution.Arius seems to have evolved fromOsteogeneiosus like ancestor whereasBatrachocephalus appears to be fromKetengus like fishes.Arius is much more advanced than all other Indian genera and has been able to proliferate and reach wider areas than the others. An intermediate connecting link betweenKetengus andOsteogeneiosus appears to be missing about which information is lacking at this stage.