OBSERVATIONS ON THE BREEDING OF THE PALILA PSITT1ROSTRA BA1LLEUI OF HAWAII

The behavioural ecology and breeding biology of the endangered Palila Psittirostra bailleui was studied from 1971 to 1975. The most intensive breeding occurred from June to August, and coincided with peak production of mamane Sophora chrysophylla seeds, the bir?s major food source. The Palila was able to make adjustments in its breeding to compensate for yearly differentiation in the timing and abundance of this food supply. Sexual chasing and courtship feeding were the most frequently encountered pre-nesting behaviours. Territory was a mate-defended area, which later in the nesting sequence was confined to the nest site. A total of 26 nests was found; most were placed on larger branches of mamane trees. Nest construction occurred primarily in the morning hours and lasted up to 20 days. Both sexes took part in nest construction, albeit the male role was minimal. Unless the nest was placed in the terminal fork of a tree, it usually contained a large stick base. The modal clutch size was two; eggs were laid early in the morning and in all cases one per day. Incubation sometimes began with the first egg and lasted 15–16 days. Only the female incubated, and she covered the eggs for about 75% of the daylight hours and throughout the night. Egg hatching was asynchronous, with the first young emerging early in the morning and the second not until later that same day. Only the female brooded, and the rate declined until day 15 when essentially it stopped. Both parents fed the young by regurgitation, and the number of feedings per hour decreased slightly over the nestling period. It is thought that insects and finely masticated plant material formed the bulk of the nestling diet until about day 5 when mamane seeds became important. Helpers were found at one nest. Young developed slowly and did not leave the nest until 21–27 days old. It is believed that these prolonged nestling periods were able to evolve because of the (former) absence of ground predators. After fledging, young remained with their parents for at least 30 days. Productivity was regulated by small clutch size, low population numbers and by the length of an individual nesting sequence (in that a pair could potentially raise only one brood each year). The primary reason for the endangered status of this bird appears to be the effect of habitat alteration upon a specialist, coupled with the fact that the small effective breeding population and low dis-persability of the species may have resulted in decreased genetic fitness.     

THE EFFECT OF pH ON THE DIVISION RATE OF THE COCCOLITHOPHORID CRICOSPHAERA ELONGATA1

The division rate of Cricosphaera elongata was measured as a function of pH in a medium buffered with the CO₂-bicarbonate-carbonate system. The optimum pH for cell division of the coccolithophorid was 7.8. A change of the partial pressure of CO₂ in the medium from 0.03 to 5% did not affect the division rate. Between pH 6.4 and 7.8 changes in the bicarbonate concentration from 0.1 to 6.0 mm and carbonate concentration from 0.007 to 0.1 mm did not affect the rate of division. At loiv experimental pH, C. elongata was nonmotile and grew in clumps; at higher pH values, it was motile and solitary. Coccoliths were not found covering C. elongata if calcite was soluble in the medium.     

日本血吸虫童虫在终宿主体内的生长发育

本文对日本血吸虫童虫从终宿主的皮肤至肝门脉系移行过程的生长发育特点进行观察和分析,发现皮肤、肺、秆门三型童虫的体形、体长、体积、面积,发育率及生长速度均呈动态变化,而且这些变化与其生理功能是相适应的,因而为童虫体外培养、血吸虫病的免疫和药物预防研究提供材料来源和评价标准。     

THE TEMPORAL PERCEPTION OF MENTHOL1

Although menthol is a common ingredient in pharmaceutical and food products, its sensory properties have not been studied extensively. The objective of this study was to describe and compare the temporal properties of l- and d-menthol. The cooling, burning, and bitterness of two menthol isomers (l-, d-) each at 0.01, 0.02, 0.04, 0.08% (w/v) in aqueous solution were evaluated by 11 trained panelists using time-intensity methodology. The intensity of all three attributes were evaluated continuously from introduction of the sample into the mouth, through expectoration at 10 s, until the termination of the sensation. The l-menthol samples had a greater maximum intensity and longer total duration of cooling and burning sensations than the d-menthol samples. In addition, maximum intensity and total duration of cooling and burn increased with concentration. In contrast, the total duration of the burning sensation was only dependent upon concentration of the l-isomer. Increasing menthol concentration significantly increased maximum intensity and total duration of bitterness for both isomers.