Notes on the behavioural ecology of the Magnificent Frigatebird Fregata magnificens

The Magnificent Frigatebird population breeding on Man-o-War Cay, Belize in 1980 laid their single eggs between mid-December and early April, and had a mean hatching date of mid- to late April. There were no differences between the sexes in the percent of time spent incubating eggs or brooding small chicks (males 48%, females 52%). However, males were not observed to feed larger (75–100 d) chicks. All 81 feedings of juvenile (approximately 1 year old) frigatebirds observed during 126 hr of observations were by females, and the majority of these feedings occurred at midday (46%) when approximately equal numbers of females and juveniles frequented the study area. Our data confirm Diamond's (1972, 1973) reports of unequal roles in chick rearing and post-fledging care between male and female F. magnificens , and support the hypothesis that males and successful females may breed at one- and two-year intervals, respectively.     

The Effects of Rapid and Very Slow Speeds of Drying on the Ultrastructure and Metabolism of the Desiccation-Sensitive Moss Cratoneuron filicium (Hedw.) Spruce

The response of the semi-aquatic moss species Cratoneuron filicinumto desiccation varies with the speed at which it loses water.On rehydration following rapid drying the contents of all cellsare considerably disrupted and they become increasingly disorganizedover a 24 h time period. After very slow drying some cells havethe appearance of those after rapid drying, while others maintaintheir integrity, and the internal organization of mitochondriaand chloroplasts is evident The capacity to resume protein synthesison rehydration is reduced after very slow, slow, and rapid drying:the greater the speed of drying the more it is reduced. Rapidwater loss down to 50% of original fresh weight has no irreversibleeffect on protein synthesis. Respiration does not occur on rehydrationafter rapid drying, although failure to maintain sterile conditionsduring measurement of oxygen consumption can lead to artefactsdue to bacterial contamination. The results are contrasted withthose obtained previously from the desiccation-tolerant mossTortula ruralis, and possible reasons for the differences areoutlined.     

Biases in Studying the Diet of the Bearded Vulture

Abstract: We compared methods of assessing the diet of the bearded vulture (Gypaetus barbatus) during the nestling period in the Pyrenees, northeast Spain. We determined diet from direct observations of food items delivered to the nest, recent prey remains present in the nest, remains collected in the nests after fledging, and remains collected in the ossuaries (bone-breaking sites). Data suggest that direct observation (food items delivered and recent prey remains present in the nest) is the only valid method of assessing the bearded vulture's diet accurately. Remains overestimated the presence of large mammals, such as cows (Bos taurus) and horses (Equus caballus), Suidae, and birds; delivered samples contained a higher proportion of small mammals, medium-sized mammals, micromammals, and reptiles. Ossuaries also differed from delivered samples because remains collected there overestimated large and medium-sized mammals. Concerning the skeletal parts, ossuaries, compared to all other methods, underestimated extremities and overestimated long bones, such as femur, humeri and tibiae, scapulae, vertebrae, and skulls. Remains samples, which overestimated scapulae, also differed from delivered and present samples. Our results suggest that bearded vultures favor extremities of prey (78% of the mammal remains, which make up 95% of the diet). The prevalence of small carcasses (almost 17%) suggests that vultures select small animals for food for the young. Because food quality may influence breeding success, future conservation projects based on the selective provision of food to breeding pairs should add to food stations meat remains and small carcasses consistent with our assessment of the birds’ dietary needs.     

Studies on Ectomycorrhizae of Pine II. Growth Inhibition of Mycorrhizal Fungi by Volatile Organic Constituents of Pinus silvestris (Scots Pine) Roots

The effects of several monoterpenes and the sesquiterpene longifolene on the vegetative growth of two mycorrhizal fungi, Boletus variegatus and Rhizopogon roseolus, were studied in petri plate experiments on an agar medium. The test substances are natural constituents of Pinus silvestris (Scots pine) roots. Vapors from 20 μl of all the test substances, upon a 5 day exposure inhibited the growth of both the mycorrhizal fungi 55% to 86%. The two fungi, however, differed in their tolerance to individual compounds. It is suggested that the terpenes and the sesquiterpenes play an important role in the development of the symbiotic condition in ectomycorrhizae by restricting the growth of the mycorrhizal fungi within the host root.     

Antifungal Activity in Passiflora Species

A substance toxic to a considerable number of fungi has beenfound in 27 species and four hybrids of Passiflora and in somegenera of the related families, Turneraceae and Flacourtiaceae.It is found in living tissues particularly after wounding. Theactive principle moves from living tissues into agar and intowater. It can be extracted from water diffusates by organicsolvents.     

THE EFFECT OF NISIN ON THE GROWTH OF CELLS AND SPORES OF CLOSTRIDIUM WELCHII IN GELATINE

SUMMARY: The action of various concentrations of nisin on the development of cells and spores from untreated and heated suspensions of Clostridium welchii added to gelatine has been investigated, using a tube colony count technique. The development of vegetative cells was prevented by the presence of 2 Reading Units (R.U.) of nisin/ml of the final culture medium, although the effective concentration may have been 6 R.U./ml. Approximately 40 R.U./ml prevented colony formation from spores. Gelatine containing nisin was dried. A considerable proportion of the activity of the antibiotic was still present after storage for 5 weeks.