SKIN SWABBING FOR GENETIC ANALYSIS: APPLICATION TO DUSKY DOLPHINS (LAGENORHYNCHUS OBSCURUS)

Exfoliated skin was collected from bowriding dolphins with the use of a sterilized nylon scrub pad affixed to a wooden dowel. Initial tests of the effectiveness of the technique and dolphin behavioral responses were conducted on dusky dolphins off Kaikoura, New Zealand. During 14 sampling days, 128 contacts using this procedure were made with bowriding dolphins, of which 114 showed behavioral response. Responses during sampling were mild, with 11% of contacted individuals showing no visible response, and 66% of individuals which could be monitored for 30 sec after contact returning to bowride within 30 sec. Mean return time was 10 sec postcontact and did not vary significantly for groups of different sizes. Behavioral controls suggest that a proportion of responses could be explained by typical dolphin behavior in the presence of boats. Seventy-eight percent of contacts resulted in successful collection of tissue samples. Sample time was three minutes on average. Size of group and behavioral state did not appear to influence sample time. Preliminary genetic analyses revealed that tissue collected by this technique was suitable for amplification and sequencing of mitochondrial DNA (mtDNA) via PCR. Comparisons of mtDNA control region sequences with those from known L. obscurus and other delphinid samples verified that this technique was robust against contamination from elements in sea water.     

DUSKY DOLPHIN (LAGENORHYNCHUS OBSCURUS) FORAGING IN TWO DIFFERENT HABITATS: ACTIVE ACOUSTIC DETECTION OF DOLPHINS AND THEIR PREY

Active-acoustic surveys were used to determine the distribution of dusky dolphins and potential prey in two different New Zealand locations. During seven survey days off Kaikoura Canyon, dusky dolphins were found within the DeepScattering Layer (DSL) at 2000 when it rose to within 125 m of the surface. As the DSL rose to 30 m at 0100, the observed depth of dolphins decreased, presumably as the dolphins followed the vertical migration of their prey. Acoustically identified subgroups of coordinated animals ranged from one to five dolphins. Time, depth of layer, and layer variance contributed significantly to predicting foraging dusky dolphin subgroup size. In the much shallower and more enclosed Admiralty Bay, dolphins noted at the surface as foraging were always detected with the sonar, but were never observed in coordinated subgroups during the brief (two-day) study there. In Admiralty Bay dolphin abundance was correlated with mean volume scattering from potential prey in the water column; and when volume scattering, an index of prey density, was low, dolphins were rarely present. Ecological differences between the deep waters of Kaikoura Canyon and the shallow nearshore waters of Admiralty Bay may result in differences in how, when, and in what social groupings dusky dolphins forage.     

GASTROINTESTINAL HELMINTHS OF THE DUSKY DOLPHIN,LAGENORHYNCHUS OBSCURUS (GRAY, 1828), OFF PATAGONIA,IN THE SOUTHWESTERN ATLANTIC

The stomachs and intestines of 23 dusky dolphins incidentally caught in a trawl fishery off Patagonia were surveyed for helminths. All the dolphins were parasitized, with a total of 3,936 helminth individuals. Only five species occurred, of which three were common (prevalence ± 10%): Anisakis simplex, Braunina cordiformis and Hadwenius sp. A. simplex was present in all the dolphins and showed the highest abundance and mean intensity (104.9 individuals/infected host). B. cordiformis was next most common (87%), and Hadwenius sp. third (52.2%). A. simplex was found mostly in the stomach (94.8%), B. cordiformis in the duodenal ampulla (51.4%), and Hadwenius sp. in the stomach (64.5%). The rare species Corynosoma australe (immature specimens) and Pholeter gastrophilus occurred in the stomach. A. simplex and B. cordiformis showed a clumped distribution along the intestine. Brillouin's diversity and evenness indices for the intestinal helminth community were 0.329 and 0.393, respectively. The diversity values and the number of parasite species were within the range for other small cetaceans.     

瓦氏黄颡鱼的繁殖生物学研究

研究了长江中游嘉鱼至新滩口江段瓦氏黄颡鱼的繁殖生物学。性腺发育可分为6个时期。4-7月性成熟系数较高,为繁殖季节。雌、雄鱼的肥满度和脂肪系数在繁殖前和繁殖后各出现1个峰值,繁殖期出现最小值。绝对繁殖力为1088-19765(粒),平均7728±4093(粒);相对繁殖力为23-88(粒),平均55±16(粒)。绝对繁殖力与体长、体重和年龄呈显著的正相关,其中体重与绝对繁殖力的关系最密切。群体性比接近1:1。属一次性产卵类型。两性最小性成熟年龄均为2龄。为补充群体占优势的繁殖群体。     

SOME OBSERVATIONS ON THE REPRODUCTIVE BIOLOGY OF GAULTHERIA PROCUMBENS (ERICACEAE)

The pollination and fruit production of Gaultheria procumbens L. (Ericaceae), an evergreen sub-shrub, were studied in five woodland sites in New Jersey and one in northeastern Pennsylvania. Pollinator exclusion methods at three of the sites produced no consistent differences in fruit and seed set between enclosed plants and controls. Insect pollinators, almost exclusively bumblebees, were sparse at all sites; visitation rates were about 0.01 bee visits/flower/hr. All fruits examined contained at least 35 seeds, but about half of the pistils examined, from open-pollinated plants, did not contain enough pollen tetrads on their stigmatic surfaces to fertilize this number of ovules. However, the low average fruit set of 8.2% on open-pollinated plants was due more to the high mortality of buds prior to anthesis than to inadequate pollination. Bud mortality was high and fruit set low in 3 years of observations at various study sites, indicating that this may be a general pattern for the species in northeastern United States and adjacent Canada. The amount of sexual reproduction showed no consistent relationship to stem density.     

AERIAL SURVEYS FOR COASTAL DOLPHINS: ABUNDANCE OF HECTOR'S DOLPHINS OFF THE SOUTH ISLAND WEST COAST, NEW ZEALAND

Line-transect surveys of abundance depend critically on the estimation of detection probability, which includes corrections for availability and visibility. In this aerial line-transect survey for Hector's dolphin ( Cephalorhynchus hectori ) we recorded dive times from a helicopter to estimate the proportion of time that dolphins could be seen at or near the water surface and were therefore "available" to be counted. The proportion of available sightings that were counted on transect lines was estimated by comparing sightings by two independent teams of two observers in the fixed-wing plane. The survey covered the area between Farewell Spit and Milford Sound, off the west coast of the South Island of New Zealand. Survey effort was stratified according to existing distribution data. A total of 142 separate sightings was made on 1,355 km of trackline. Average availability for fifty Hector's dolphin groups observed from the helicopter (161 dive/surface cycles) was 46.3% (CV = 4.2%). Data from the two independent observer teams indicated that 96.2% (CV = 2.3%) of the dolphin groups that were at the surface and on the trackline were seen. The abundance estimate for the South Island west coast, corrected for visibility and availability, was 5,388 Hector's dolphins (CV = 20.6%). The total population estimate for South Island Hector's dolphins is 7,270 (CV = 16.2%).     

大熊猫繁殖生物学初步研究

近年来,在动物园内人工饲养下的大熊猫(Ailuropoda melanoleuc),由于雌雄个体常常不能同时发情,甚至都不发情,因而不能正常产仔。故大熊猫的繁殖问题就成为国内外各动物园所关注的问题之一。 北京动物园大熊猫于1963年自然交配产仔首次成功。1978年以后,国内外动物园又相继进行了上百次的人工授精试验,据报道,真正受孕产仔的仅有中国的北京、上海、成都、杭州以及西班牙的马德里和墨西哥等动物园。可见其受精率很低。     

SOME NOTES ON THE BIOLOGY OF THE CLICK BEETLES AGRIOTES OBSCURUS L. AND A. SPUTATOR L.

Wire-worms rarely occur in permanent arable land in sufficient numbers to cause serious damage to crops. Various workers (e.g. Roebuck, 1924; Hawkins, 1936; Miles & Cohen, 1941) have noted the reduction in numbers of wireworms in successive years on ploughed-out grassland. At Rothamsted reductions of 62 % in one year and 85 % in two years were recorded on plots on Highfield. This reduction is certainly due in part to the exposure of wireworms to their natural enemies and to the direct effect of disturbance by implements of cultivation. It has also frequently been suggested that the beetles prefer to oviposit on grassland or clover leys and to a lesser extent on cereal crops (Bryson, 1930; Rawlins, 1934; Balachowsky & Mesnil, 1935; Miles & Cohen, 1938). A laboratory experiment to test this point was accordingly carried out in June 1940.     

鲸类繁殖生物学的研究概况

生殖是生物繁殖自身的能力,生殖过程包括生殖细胞(精子与卵子)的生成与成熟、受精过程、妊娠、胎儿的发育、分娩等环节。       

NOTES ON THE BIOLOGY OF SOME AUSTRALIAN STICK INSECTS (PHASMATODEA)

i
Specimens of the Phasmatodea, Eurycnema goliath (Gray), Podacanthus typhon Gray and Tropidoderus childrenii (Gray), were reared in the insectary and observations on longevity and fecundity were made. Facultative thelytokous parthenogenesis may exist in the last two species.     

张氏(餐)的繁殖生物学特性

文章对赤水河河口段张氏(餐)的繁殖生物学进行了研究.结果表明:5-9月份为其繁殖期;最小性成熟个体为雌性体长77mm,体重5.3g;雄性体长108mm,体重9.4g,均为1龄;繁殖群体性比为1.07:1,由4个年龄组组成,其中2龄个体占绝对优势.性成熟系数3-7月份逐渐增大,然后持续减小,至12月降到全年最小值.卵径(0.75±0.14)mm呈单峰型,绝对繁殖力(11010±7723)粒,相对繁殖力(275.1±138.4)粒/g,每克卵巢卵粒数(3789±1389)粒.该种为单批产卵类型鱼类.绝对繁殖力随着鱼体体长、体重和年龄的增长而增大.