Volume 93, Issue 5
September 1984, pages 407-504
pp 407-410 September 1984
Nature of infection, sites of localization and propagule production byCunninghamella echinulata (Matruchot) Thaxter,Metarrhizium anisopliae (Metchnikoff) Sorokin, andPenicillium Link ex. Gray, onElaphrothrips denticollis (Bagnall), a sporophagous tubuliferan, were studied using a scanning electron microscope.
pp 411-417 September 1984
Parabolic equations describing the body length-body weight relationships in 311Labeo dero (Ham.) are determined. The differences between regression coefficients of the two sexes and length classes were highly significant. The difference between regression coefficients of the two length classes was significant at 5% level.
pp 419-430 September 1984
Ecology of biofouling on the edible estuarine oysterCrassostrea madrasensis (Preston) has been investigated in the Ashtamudi Backwater of the southwest coast of India. Fouling was highly conspicuous throughout the year and dominant groups included barnacles, serpulids, bryozoans and modiolids. Intensity of fouling varied from 73 to 179 % on living oyster valves and 65 to 172 % on dead valves with respective annual averages of 118 and 127%. Substrate selection and settlement of the different groups were mostly opportunistic. Barnacles were the most dominant, living and dead ones collectively contributing to about 26 % of fouling on living valves and 32 % on dead valves. Serpulid fouling was 22 % both on living and dead oyster valves, bryozoans 15 and 12%, modiolids 11 and 12% and the miscellaneous groups formed 27 and 20 % respectively. Availability of free settling space and fouling in relation to substrate size were also investigated. Total fouling was very intense on oysters of 25–35 cm2 size group. Impact of biofouling on oysters and certain earlier studies on the topic are discussed.
pp 431-436 September 1984
In a choice test, the Indian gerbils,T. indica preferred urine-mixed food over ordinary millet indicating a phago-stimulant nature of conspecific urine. The experiments also revealed that addition of conspecific urine mitigates the poison aversion and bait shyness behaviour significantly, as a result of which zinc phosphide poisoning can be attempted a second time in a sequence, thus enhancing the control success.T. indica showed a clear preference for urine of the same sex which suggests that the active attractant in the urine has no sex attraction.
pp 437-443 September 1984
The food preference ofP. canius, carried out from fish samples of Hooghly-Matiah estuary and Chilka lake is described. Qualitative study of the food showed the species to be a predatory carnivore right from its fingerling stage. The study justifies the inclusion of the species in brackishwater aquaculture as a biological control of unwanted crabs.
pp 445-453 September 1984
In a factorial design of experiment, effects of feeding frequency on food utilization were studied inChanna striatus. Feeding frequency is positively related, whereas density is negatively related to the tested energetics components; absorption efficiency remains independent of both feeding frequency and density. Based on the minimum water requirement, a fish pond with an average depth of 1·5 m and an area of 1 ha could be stocked with 1·15 million fry ofC. striatus, of size 3 g. There is a significant interaction between feeding frequency and density suggesting that adverse effects of density could be compensated by increasing the frequency of feeding.
pp 455-461 September 1984
The preliminary light microscopic and biochemical study of the haemolymph ofOxya hyla hyla records the presence of five different types of haemocytes and gives a quantiative estimation of plasma proteins along with their gel electrophoretic band patterns. The higher number of total haemocyte count in adult female compared to that of immature one may be attributed to some kind of synthesis and transport of proteins or other yolk materials during vitellogenesis. High plasma protein concentration during monsoon may be associated with the reproductive maturity of these insects. The gel electrophoretic pattern of plasma proteins reveals the constant presence of two particular bands suggesting the occurrence of lipoprotein and juvenile hormone carrier protein.
pp 463-483 September 1984
The development of foetal membranes and the changes in the structure of the placenta in the batMiniopterus schreibersii fuliginosus is described. The study reveals thatM. schreibersii fuliginosus exhibit developmental characters not matched by any other mammal let alone any other bat.
pp 485-489 September 1984
The spotted bollworm,Earias vittella (Fabricius) passed through four overlapping generations in insecticides treated cotton field. The parasitisation due toMicrochelonus sp andBracon sp was 8–43 and 19–26% during first generation.Rogas aligarhensis (Quadri) is the important larval parasite of spotted bollworm in Marathwada region.
pp 491-496 September 1984
Studies were made on 516 specimens of Western ghat squirrel,Funambulus tristriatus collected from cocoa—coconut cropping systems in Western ghat biome of South India. Sex ratios, body weights and age structure factors ofF. Tristriatus are compared with sciurid species in India and other countries.
pp 497-504 September 1984
Dietary water intake in Eri-silkwormPhilosamia ricini fedad libitum castor leafRicinus communis from hatching to pupation at 26±2°C averaged 16174 mg/insect. As much as 3966 mg of dietary water is lostvia faeces and 65% of the absorbed water is lost through transpiration retaining only 35% in the body. Rates of water intake, absorption, lossvia faeces and transpiration decrease from the Ist instar to Vth instar larvae and are correlated to the increasing body weight and/or age. Water intake inP. Ricini fed permethrin, a pyrethroid insecticide, treated leafR. Communis averaged 8649 mg/insect which is about 50% less than the normal intake. Water utilization in the insecticide fedP. Ricini is considerably less than the normal. It is suggested, the mechanism by which insecticide inhibit the utilization of water could be through, repellency, disruption of feeding physiology and other chronic toxicity possibly related to insecticide action.