The use of cell cultures in human genetics

Advice on rearing locusts is followed by suggestions for simple investigations, needing only inexpensive equipment, which will help students to understand the circumstances in which locusts become a major threat to food supplies in many parts of the Tropics.     

Behavior of nursery/peer-reared and mother-reared rhesus monkeys from birth through 2 years of age

The behavior of 8 nursery/peer-reared and 16 mother-only reared rhesus macaques was observed between birth and 5 months of age, with follow-up studies conducted when the animals were 10–21 months old and living in large social groups. Nursery-reared neonates were more awake, active, and irritable than mother-only reared monkeys. From 1 to 5 months of age the nursery/peer-reared animals exhibited a greater variety of behaviors than the mother-only reared infants, which spent the majority of the time in ventral contact with mothers. As juveniles the groups were indistinguishable with the exception of more self-directed behaviors observed in the nursery/peer-reared monkeys. Both rearing conditions, by virtue of their atypicality, imposed restrictions on social development. The behavioral similarity of the juveniles while in the large social group may be a function of maturation or due to the rehabilitative effect of the large social group.     

Predation avoidance and foraging efficiency contribute to mixed-species shoaling by tropical and temperate fishes

The formation of mixed-species social groups, whereby heterospecifics form and maintain either transient or stable groups with each other, can confer substantial fitness benefits to individuals. Such benefits may arise via multiple mechanisms associated with both predation avoidance and foraging efficiency. In fishes, mixed-species shoaling reportedly occurs where displaced tropical species (known as “vagrants”) interact with resident temperate species, although little is known about the nature and frequency of such interactions. To investigate this phenomenon, we used displaced tropical Indo-pacific Sergeant Abudefduf vaigiensis settling in temperate south-eastern Australia as a model system. Underwater visual surveys revealed shoal composition and size differed significantly between open-water and reef habitats, with shoals in open habitats being larger and more speciose. Shoals containing A. vaigiensis were mainly mixed-species, and larger and more speciose in open habitats than nearer to reef. Since both foraging efficiency (via access to plankton) and predation threat likely increase with increasing distance from reef habitat, we suggest that mixed-species shoaling mitigates predation risk whilst allowing increased foraging opportunities for A. vaigiensis in open areas. These findings provide support for the importance of mixed-species shoaling to the persistence of tropical reef fishes in temperate regions.     

黄腹角雉的饲养繁殖

笼养下黄腹角雉自３月下旬开始产卵,６月中旬结束,产卵期持续近３个月。年产窝数３．５窝,年均产卵１０．８枚／只雌鸟。１９９４,１９９５年卵的受精率和化率分别为２６．７％。１２．５％和６８．６％,４７．８％,对孵化率人低的原因进行了总结分析。     

Variation in structure and distribution of pre-spawning Pacific herring shoals in two regions of British Columbia

In two regions of British Columbia, small and medium-sized shoals of pre-spawning Pacific herring Clupea harengus pallasi were most numerous and occurred as neighbours more frequently than would be expected by chance. Herring displayed a typical diurnal vertical migration, although shoals in the Central Coast were more evenly distributed through the water column during the day than those in the Strait of Georgia. As maturation progressed, shoals were found in shallower water, more densely packed and vertically extended in shape. In the Strait of Georgia, shoals were considerably larger, and positioned relatively deeper in the water column. Very large (>5000 t) shoals were found at specific locations characterized by high water exchange. Large shoals may act as an anti-predator strategy to the abundant sealions and birds. Moreover, staying deep in the water column, and associating with dips in the sea bed, reduces predation risk and confers energy savings through hydrodynamic advantage. Smaller, denser, vertically extended, travelling shoals, prevalent during the later stages of gonad maturation, were similar in nature to labile spherical shoals observed in the Central Coast at different locations each day. Both these shoal types may benefit from synchrony and co-ordination when evading predators that is not possible for larger shoals. The more highly clustered distribution of shoals in the Central Coast is presumed to be linked to their tight association with rock outcroppings typical of this region.     

基于遥感分析的锦州湾海域填海造地变化

利用Landsat TM和高精度ALOS影像数据,在比较不同水体指数提取海域面积精度的基础上,利用改进的归一化差异水体指数(MNDWI),研究了1988、1995和2006年锦州湾海域填海造地情况.结果表明:1988-2006年间,锦州湾海域填海造地面积达23.63 km2,其中,12.38 km2被用作开发区建设,5.48 km2用于工业用地,3.47 km2用于码头建设,1.37 km2被用作养殖用地,0.93 km2被用为滨海浴场.大面积填海造地反映了锦州湾沿海城市建设和经济发展对土地的强烈需求,同时也必然会对该区域的生态环境造成较大影响,需要进一步加强监测和评价.     

A note on light preference in layer pullets reared in incandescent or natural light

The effect of early exposure of pullets to natural light may have an effect on the later preference for light type and on the behaviour of birds after being transferred to laying facilities. Our aim was to study the light-type preference of 14-week pullets reared in either incandescent or natural light. From day-old, a total of 84 LSL chicks were subjected to two light treatments with six groups of seven birds each: 8 h incandescent light + 16 h darkness (I8), and 8 h natural light + 16 h darkness (N8). At the age of 14 weeks, the birds’ light-type preference was tested. Behaviour was recorded at the group level and analysed by a linear mixed model. Predicted mean proportion of birds that chose natural light was 0.36 in N8 and 0.13 in I8 groups. I8 groups showed a preference for incandescent light, in contrast to N8. These results support the notion that pullets for organic egg production shall be reared with access to natural light.     

Kleptoparasitic prey competition in shoaling fish: effects of familiarity and prey distribution

Familiarity is thought to stabilize dominance hierarchies andreduce aggressive interactions within groups of socially livinganimals. Though familiarity has been widely studied in shoalingfish, few studies have investigated changes in prey competitionas a function of time spent together within groups of initiallyunfamiliar individuals. In this study, we created shoals ofthree-spined stickleback (Gasterosteus aculeatus) and monitoredchanges in foraging rates and related competitive behaviorswithin shoals over a 4-week period in experimental series whereprey was spatially and temporally concentrated or dispersed.Prey share was unequal under both prey distribution modes, anddisparity in prey share was not seen to change as trials progressed.Interestingly, the contest rate for prey items fell over timewhen individuals were competing for dispersed prey but not whenprey were concentrated. We found no evidence that fish showedassociation preferences for either group members that had consumeda greater or lesser proportion of prey during trials. Thoughthe intensity of competition may be reduced by increased groupstability in nature, this is likely to be strongly dependenton the way prey resources are distributed through space andtime.