雪豹饲养与繁殖的初步研究

雪豹(Panthera uncia Schreber)是典型的高山动物,终年生活在气候寒冷、光照充足、海拔3200-5300米的高寒山区。我国主要分布在青海、西藏、新疆、甘肃、四川等省区。现已列为我国一类保护动物。 据世界动物园年刊统计,1967年以前,在全世界33个动物园中供观赏的雪豹共有46只(不包括我国数字),其中仅有15只是在人工饲养条件下出生的(苏联考纳斯动物园,1968)。1983年我国各地动物园供观赏的雪豹共35只。尽管在北京、上海、大连、银川、烟台、乌鲁木齐、西宁等7个动物园中均有雌雄配对的雪豹,但繁殖问题一直未获解决。     

The effect of sex and shoal size on shoaling behaviour in Danio rerio

Male and female zebra fish Danio rerio were given choices of shoals that differed in sex and size. Male zebra fish preferred to associate with female shoals over male shoals, but had no preference when given a choice between a mixed‐sex shoal and either a male or female shoal. Female zebra fish showed no significant preference when given a choice between male and females shoals, nor between mixed‐sex shoals and either male or female shoals. When given choices between shoals of differing size, females preferred to associate with the larger shoal, whether or not they were composed of males or females. Males, however, had no preference for larger shoals over smaller shoals, whether or not they were composed of males or females. These results showed that male zebra fish were capable of distinguishing between males and females solely on the basis of visual cues. Furthermore, these results demonstrated a significant difference between the shoaling choices of male and female zebra fish, which may indicate a difference in the function of shoaling for the two sexes.     

A modified rearing system for production of Pseudacteon curvatus (Diptera: Phoridae), a parasitoid of imported fire ants

A self-contained, climate-controlled box for exposing fire ants to attack by Pseudacteon parasitoids was developed. The initial system, which is being used to rear Pseudacteon tricuspis Borgmeier, consists of large (about 244 cm L × 97 cm W × 50 cm H), well-ventilated boxes (“attack boxes”) housed in a climate-controlled room (approx. 28 °C, 80% RH, 12:12 (L:D) h). Adult flies emerge into the boxes, which contain live host ants (Solenopsis invicta Buren). Host ants are confined in a series of trays within the box, each containing a pair of inverted cups under which the ants can hide. The cups alternate up and down, inducing the ants to trail back and forth within each tray. A modified system used for Pseudacteon curvatus Borgmeier consists of closed boxes, through which preconditioned air is pumped to maintain high relative humidity. Steam is used to generate humidity in a small, temperature-controlled room from which conditioned air is drawn, and infrared heating elements mounted above the attack box prevent condensation. This new system maintains high relative humidity (range 80–90%) crucial for activity and survival of P. curvatus. System performance was monitored in 4 ways: (1) environmental conditions within the system (RH, temperature, dew point, and light intensity); (2) production of P. curvatus; (3) successful development and emergence of P. curvatus; and (4) attack rates throughout the box. The modified system is capable of producing >1400 flies/day/attack box. This system will be useful for researchers with limited space in which rearing and research activities are conducted simultaneously.     

Juvenile Chinook salmon (<Emphasis Type="Italic">Oncorhynchus tshawytscha</Emphasis>) growth in off-channel and main-channel habitats on the Sacramento River,CA using otolith increment widths

Few studies have quantified juvenile salmon growth among different habitats or evaluated the mechanisms controlling salmon growth and survival. We used otolith microstructure to compare daily relative growth rates among main-channel riverine areas, off-channel ponds, and non-natal seasonal tributaries of the Sacramento River, CA. We compared prey availability, prey preference, and stomach fullness between these sites. We observed larger average otolith growth increments, higher prey densities, and warmer water temperatures in both off-channel ponds and non-natal seasonal tributaries compared to the main-channel areas in both 2001 and 2002. Our findings suggest that warmer temperatures and abundant prey in off-channel habitats during Central Valley Chinook salmon rearing periods may lead to higher growth rates, which in turn may improve juvenile survival. Our results suggest that off-channel habitats may be critical habitats to include in conservation and management plans for juvenile salmon.     

养殖密度对史氏鲟消化率、摄食率和生长的影响

以体重（43.90±1.75）g史氏鲟为研究对象,研究了0.525、1.171和2.138 kg·m^-2 3种养殖密度对史氏鲟幼鱼生长、摄食率和消化率的影响,实验时间为60 d.结果表明,养殖密度对史氏鲟的生长、摄食率和消化率具有显著影响.高养殖密度不利于史氏鲟的生长,低密度组中史氏鲟的特定生长率和日增重显著高于高密度组,食物转化率显著低于高密度组;特定生长率和日增重随养殖密度的降低而显著增高.低密度组、中密度组中史氏鲟的消化率无显著差异,但均显著高于高密度组.中密度组摄食率显著低于高密度组和低密度组,低密度组摄食率介于两者之间;食物转化率和消化率呈显著负相关,特定生长率与消化率呈显著正相关.     

圈养大熊猫母兽成功哺育双胞胎成活初探

圈养大熊猫产下双胞胎后,母兽一般难以同时哺育二仔。2003年,圈养大熊猫母兽“梅梅”同时哺育双胞胎成活,本文对该首例哺育双胞胎成活的原因进行了初步分析,认为满足母兽的营养需求、适宜的育幼环境及人工护理,特别是“梅梅”的母性好、有丰富的育幼经验、食欲强、泌乳充足等在同时哺育双胞胎成活中起着重要作用,同时对“梅梅”哺育的双胞胎与其哺育的另两只单胎幼仔的体重增长情况进行了比较,为圈养大熊猫成功哺育双胞胎,增加幼仔成活率,提供了有关借鉴信息和资料。     

Tasty straw pellets – Exploration of flavoured rooting material by pigs

Tail biting is a common problem in pigs kept in conventional fully slatted pens. Suitable enrichment materials can help to prevent the occurrence of this behavioural disorder by encouraging pigs to increase exploration behaviour. We investigated whether additional flavours can increase exploration behaviour in undocked pigs. Therefore, we offered straw pellets flavoured with either fried onion (FO), strawberry (SB), ginger, almond (AL), vanilla or without flavour (control) during rearing (eight groups in total) and fattening (16 groups in total). Flavoured pellets were offered in an altering order during intervals of 1 week in material dispensers. Exploration duration at the material dispensers was continuously recorded via an ultra-high-frequency radio-frequency identification system. Pigs were weighed weekly and their tail lengths and tail injuries were scored in four categories. For analysis, changes in tail length scores compared to the previous week were calculated as Δ-tail length. The different flavours affected pigs’ exploration durations in both rearing (factor flavour, P < 0.0001) and fattening (factor flavour, P < 0.0001). Highest exploration durations during rearing were recorded when straw pellets were flavoured with FO and AL compared to all others. During fattening, exploration duration was highest towards controls without significant difference to SB. Exploration durations additionally were affected by temporal effects, i.e. week and day during rearing (both factors: P < 0.0001) and fattening (both factors: P < 0.0001). During rearing, highest exploration durations were recorded in the first week and on the first day within week after changing the flavour of the straw pellets. During fattening, exploration durations varied between weeks and within weeks. The highest durations were recorded at the end of weeks, i.e. on the fifth and seventh days after material change. During rearing, tail injuries were affected by week (P < 0.0001). From the fourth week of rearing, the prevalence of tail injuries significantly increased. During the fattening period, tail injuries were affected by flavour (P < 0.05). Fattening pigs had fewest tail injuries after straw pellets flavoured with AL were offered. Altogether, based on the exploration durations, rearing pigs showed different preferences for the flavoured straw pellets but highly explored flavours differed between rearing and fattening pigs. Despite a weekly change of the flavour of straw pellets, exploration durations decreased during rearing but increased again in the transition between rearing and fattening. Thus, straw pellets with alternating flavours are a suitable possibility to provide environmental enrichment to pigs but will not prevent tail biting.     

Comparative rearing parameters for bisexual and genetic sexing strains of Zeugodacus cucurbitae and Bactrocera dorsalis (Diptera: Tephritidae) on an artificial diet

The Sterile Insect Technique (SIT) is an important component of area wide programs to control invading or established populations of pestiferous tephritids. The SIT involves the production, sterilization, and release of large numbers of the target species, with the goal of obtaining sterile male x wild female matings, which yield infertile eggs. A major advance in SIT involved sex-linked, genetic manipulations that allowed the production and release of male-only strains (also termed genetic sexing strains, GSS). The use of GSS avoids matings between sterile males and females, which may divert males from seeking and mating with wild females, and studies show that male-only releases result in greater suppression of wild populations than standard bisexual releases (i.e., those including both males and females). GSS based on sex-linked pupal color exist for Zeugodacus cucurbitae (Coquillett) and Bactrocera dorsalis (Hendel), two important agricultural pest species, but their rearing characteristics have not been documented in detail. The goal of the present study was to compare the pupal color sexing and bisexual strains for each of these species with respect to important rearing parameters, including egg production and eclosion of larvae from eggs (egg hatch), pupal recovery, and weight, emergence rate, and flight ability. In both species, most of these parameters were significantly greater for the bisexual strain than the GSS, and, for a given number of eggs, the production of flight-capable adults was approximately 2 times greater in the bisexual strains of both species. The potential usefulness of GSS in SIT against Z. cucurbitae and B. dorsalis is assessed based on these findings.     

Effects of group size on school structure and behaviour in yellow‐eyed mullet Aldrichetta forsteri

Schooling behaviour in yellow‐eyed mullet Aldrichetta forsteri, a common fish species in New Zealand estuarine habitats, was investigated to identify interaction rules associated with group formation. Tank‐based three‐dimensional studies of three group sizes (15, 75 and 150 individuals) were carried out to measure the effects of these different group sizes on school structure during control, predation risk and foraging behavioural states. Increased group size positively correlated with nearest‐neighbour distance in control and foraging states. Swimming speed was the lowest in all three behavioural states in groups of 15 fish compared with 75 or 150. Immediate behavioural response following visual exposure to a simulated avian predator differed between groups resulting in loss of structure in larger groups. School shape was an oblong–oblate spheroid with a length, breadth and height ratio of 5:2:1 and the area of free space surrounding individual fish was spherical in shape with a high degree of spatial isotropy present in all size groups. These findings challenge traditional theories based on either local or global properties as key drivers of group structure. Instead, our results suggest that a more collaborative approach involving both group size and rules pertaining to nearest‐neighbour interactions affects collective behaviours in this species.     

Factors determining tool-using ability in two captive chimpanzee (Pan troglodytes) colonies

The influence of several determinants of performance in a reaching tool task were studied: rearing history, object experience, and gender. Forty-five chimpanzees between the ages of 7 and 36 years served as subjects. They were chosen from two facilities, each group having different levels of tool experience. Each group was made up of individuals from three rearing conditions: wild born, captive mother reared, and captive nursery reared. Results indicated that wild-born subjects were better at the task than were both groups of captive-born subjects, who performed similarly. Previous experience with reaching tools was not a significant factor in the determination of tool-using ability. Gender differences were not apparent for either group, and the range of ages of chimpanzees tested was not related to tool-using ability.