Volume 99, Issue 4
July 1990, pages 289-352
pp 289-303 July 1990
Vascularisation of the placenta of several species of bats representing 8 families is reported. Maternal vascularisation in all these bats is effected by a few large vessels which pass through the entire thickness of the placenta and give rise to numerous radial branches on reaching the foetal surface of the placenta. Maternal blood is returned through placental tubules which empty into large venous channels at the utero-placental junction. Foetal vascularisation is brought about by two allantoic arteries which capillarise over the placental tubules, and a large allantoic vein. In the exchange areas there is mostly crosscurrent circulation of the maternal and foetal bloods. Only in emballonurid bats is there an haematoma from which maternal blood is not drained back but is absorbed by cells of the trophoblast of chorionic villi.
pp 305-309 July 1990
Chromosomal aberrations were detected in the progenies of hydroxylammonium sulphate-induced recombinants ofaristaless-dumpy anddumpy-black regions of the males ofDrosophila melanogaster. When males from homozygous lines derived from these male recombinants were crossed to females from an aberration-free stock, the chromosomal aberrations were not recovered in recombinant heterozygotes. Implications of these observations are discussed in relation to role of chromosomal aberrations in induced male recombination inD. melanogaster.
pp 311-315 July 1990
Among 5 species ofTermitomyces spp. associated withOdontotermes spp.,Termitomyces microcarpus was the most dominant on the mound surface ofOdontotermes redemanni during the rainy season. This species was found to grow on the fungal comb fragments brought out by termites as the substrate for its growth. As a result, decrease in cellulose (5·9%), lignin (3·5%) nitrogen (0·54%), carbon (11·2%), C:N ratio (1·37), crude fat (0·48%), moisture (17·02%) and increase in ash content (20·15%) were observed. It was also observed thatTermitomyces microcarpus was rich in protein (39·16–43·37%) and mineral content.
pp 317-325 July 1990
Age correlated tissue preferences ofHeliothis armigera (Hubner) andSpodoptera litura (F) were investigated onGossypium hirsutum, Abelmoschus esculentus, Ricinus communis and Cajanus cajan. The food utilization and reproductive potential of these two noctuids are correlated with the host plant nutritional and non-nutritional phenolic substances, separated and characterised through thin-layer chromatography and UV spectra. The non-nutritional phenolic substances such as phloroglucinol, resorcinol, protocatechuic acid, gallic acid, pyrogallol and vanillic acid tend to vary within the host plant parts as well as in different host plant species. Keywords.Spodoptera litura; Heliothis armigera; age-correlated tissue preferences; nonnutritional phenolic substances.
pp 327-334 July 1990
Hatching pattern in the silkworm,Bombyx mori L. (PM × NB4D2) under different photoperiodic conditions was studied. Hatching was predominantly diurnal under natural solar day conditions (LD 12:12). The observed LD pattern prevailed under all the photoperiodic conditions. Hatching confined to a single day under all the short-day conditions as also LD 12:12 and DD conditions. All the long-day photoperiodic conditions, as also continuous light (LL), resulted in broadening of the hatching peaks with reduced amplitudes, with extended hatching for two days apart from long hatching durations with more hatching on the second day. The hatching rhythmicity seems to be under circadian control. Maximum hatching was observed under LD 11:13 photoperiodic combination. Shortest hatching duration was observed under LD 11:13 condition.
pp 335-343 July 1990
The combined effects of food (Chlorella) and temperature on the population growth of a laboratory clone of the rotiferBrachionus patulus were studied. The intrinsic rate of increase (r) as well as the maximum densities achieved were a function of temperature. While ther was negative at 15°C regardless of food level, its magnitude was dependent on food level at medium (25°C) and high (35°C) temperatures, indicating a significant temperature × food interaction. The seasonal variations in the abundance ofBrachionus patulus in the plankton of a regularly sampled pond are explained in terms of the observed food-temperature effects on the survival and reproduction of the laboratory population.
pp 345-352 July 1990
Accumulation, distribution and depuration of inorganic mercury in the gills, viscera, mantle and adductor muscle + foot of green musselPerna viridis were investigated. Mussels were exposed to 37–5 and 75 µg 1−1 mercury as HgCl2 in a static system for 4 days. The rate of accumulation was found to be the maximum in gills followed by viscera, mantle and muscle + foot. Exposed mussels were then transferred to clean seawater in a flow-through system and maintained for 25 days to study the depuration and biological halflives (TB/2) of mercury in the different body parts. After 25 days, mercury loss from the external tissues like gills and mantle was faster than from the internal tissues like viscera and muscle. Gills and mantle showed comparatively shorter TB/2 than the viscera and muscle + foot.