DIFFERENCES IN THE LIFE HISTORIES OF XEROLENTA OBVIA (MENKE, 1828) (HYGROMIIDAE) IN A COASTAL AND A MOUNTAINOUS AREA OF NORTHERN GREECE

The life cycle of Xerolenta obvia (Menke, 1828) was studiedin two areas, Paleokastro (Chalkidiki), an inland mountainousarea, and Nea Karvali (Kavala), a coastal area in northern Greece.At Paleokastro snails hatch in autumn, become adult the followingJuly, but do not lay eggs until October, after which they die.Clutch sizes are small, but eggs and hatchlings are large comparedwith those at Nea Karvali. Growth is fast in spring, and continuesuntil the end of July. The young hatchlings have dark shell-bands,but by July a quarter of snails appear unbanded. At Nea Karvali,eggs are also laid in October, and young snails emerge fromhibernation in March. Here, however, they do not mature untilApril of the following year. They thus have a 2-year life cycle,with adults dying in their second autumn. Clutches are aboutthree times the size of those at Paleokastro, but eggs and hatchlingsare significantly smaller. A little growth occurs in winter,but the rate of growth is generally much slower than at Paleokastro.Only 1–2% of this population has banded shells; the bandsare less obvious and they become invisible in some individualsas they mature. At both sites population density fluctuatedduring the two study years, but it was always higher at NeaKarvali. These results are discussed in relation to the differingclimates of the sites, and comparisons made with studies onrelated species in the region. (Received 23 July 2004; accepted 30 December 2004)     

LIFE HISTORIES, DENSITY AND BIOMASS IN A WOODLAND SNAIL COMMUNITY

Data, based on 8 monthly sets of random samples, are presentedon the life histories, densities and biomass of snail populationsin a mixed deciduous wood with moderately rich soil. Discus rotundatus, Oxychilus helveticus, O. cellarius and Trichiahispida have approximately annual life cycles, with rather littlepost-reproductive survival. Aegopinella nitiduta and Cochlodinalaminata take two years to reach maturity, and adults of thelatter may survive for several years. Breeding seasons are prolonged,but annual species peak in the autumn. Density does not vary much with season. Mean annual densityof all species combined (37.m^–2) is much lower than thoserecorded for similar woods elsewhere, but the estimate of meanannual standing crop (175 mg ashfree dry weight m^–2) doesnot show the same discrepancy. Comparisons reveal that the maincause of low density is the absence or rarity of several verysmall litter-dwelling species which have little effect on overallbiomass, and reasons for this are discussed. (Received 27 January 1981;     

CONSULTING KU JLOPLE: SOME HISTORIES OF ORACLES IN WEST AFRICA

Historical comparison of oracles in west Africa, mainly during the nineteenth century, shows how divination practices may alter. In the cases explored here, reputation, range of users, economic growth, and political influence interacted as these oracles developed; some at sites with internal and overseas trade access became complex, large-scale operations. But by about 1900, colonialists felt threatened by their secular and their spiritual power and smashed them physically, though not spiritually. Contextualized comparison shows that the many people who were involved as oracle organizers and supplicants must have had different motivations and interests. Some methodological implications of the findings are considered. As in many powerful secular organizations, access to insider knowledge was blocked, but oracular reputation was important, and the oracles had competitors. Success derived partly from collecting intelligence, with simultaneous advertisement that emphasized the mysterious power of their operations.     

意大利威尼托大区刺叶栎林的生物多样性研究

意大利威尼托大区刺叶栎（Ｑｕｅｒｃｕｓｉｌｅｘ Ｌ．）林物种多样性指数和物种多度分布的研究表明：１．Ｍｅｎｈｉｎｉｃｋ 指数、Ｓｈａｎｎｏｎ 指数、Ｂｒｉｌｌｏｕｉｎ 指数、Ｓｉｍ ｐｓｏｎ 指数、Ｐｉｅｌｏｕ 均匀度指数、Ｂｒｉｌｌｏｕｉｎ 均匀度指数、ＰＩＥ的Ｖ 均匀度指数、ＰＩＥ的Ｖ均匀度指数和ＭｃＩｎｔｏｓｈ 均匀度指数较为适用。它们反映从加尔达湖区到ＦｏｃｉｄｅｌＴａｇｌｉａｍ ｅｎｔｏ、Ｂｏｓｃｏ Ｎｏｒｄｉｏ、ＣｏｌｌｉＥｕｇａｎｅｉ刺叶栎林的物种多样性指数依次降低。２． 几何分布最适用于威尼托的刺叶栎林的物种多度分布,Ｌｏｇ－ｎｏｒｍ ａｌ分布也较适合。物种多度分布模型反映在生物多样性上,其结果与物种多样性指数一致。３． 生物多样性并非绝对随群落演替的顺向发展而增加。在演替早期,由于无明显优势种,物种的优势度较低,物种多样性指数较高。随着演替的进行和优势度的增加,多样性变小。演替的进一步进行,由于群落结构的复杂及物种的增加,多样性又将随演替发展而增加     

南海北部0.36-1.02Ma高分辨率碳屑记录及天然火

依据南海ODP1144站下段（225．7－501．3m,ca.0.36-1.02Ma)碳屑、孢粉记录,将1144站下段225.7-501.3m划分19个碳屑、孢粉组合带（11－29）,并分别与氧同位素11－29期（MIS11－29）相对应。冰期时,草本植物花粉和碳屑总沉积率增加,气候干燥,天然火的强度较大;冰期MIS24,大陆内部及冰期出露的大陆架上的天然火灾强度相对最弱;而冰期MIS12,大陆内部及冰期出露的大陆架上的天然火灾强度相对最强;间冰期气候湿润,草本花粉和碳屑总沉积率降低。一方面由于间冰期海平面上升,大陆架被淹没,导致碳屑来源减少;另一方面亦反应天然火灾强度减低。间冰期MIS17,25和27碳屑沉积率分别较冰期MIS18,24及26略高,推测间冰期MIS17,25和27冬季风强度仍相对较强,大陆内部天然火灾强度亦相对较强。     

CEPAEA NEMORALIS (L.) IN THE CHANNEL ISLANDS: ISLAND HISTORIES AND GENETIC VARIATION

Populations of C. nemoralis from the Channel Islands show strongbetween-island variation in their shell colour and banding polymorphism,despite the general similarity of the habitats sampled on eachisland. Morph-frequency distributions do not, in general, matchthose found in similar open habitats in England and Wales inregions where visual selection for crypsis is effective. Somechanges have occurred over the last 30 years, reflecting changingpatterns of land-use. A detailed comparison is made with C.nemoralis populations on the Isles of Scilly, where inter-islanddifferences are much less marked, but where morph-frequencydistributions are even more unlike those found in similar habitatson the British mainland. These patterns can be interpreted interms of rising Holocene sea-levels: the Scillies were probablycolonized once, when a single larger island existed, while manyof the Channel Islands have a history of separate isolationsfrom differing parts of the French mainland. Population historieshave an effect on present genetic make-up, even for loci onwhich selection can and does operate. (Received 20 January 1997; accepted 12 May 1997)     

甘肃白水江国家级自然保护区的蛇类调查

笔者于91～92年7月初步调查了甘肃白水江国家级自然保护区(东经104°17′～105°25′、北纬32°36′～33°15′)的蛇类,采集标本30余号,经鉴定为2科12属18种(包括甘肃新纪录绞花林蛇1种),另有资料记载4属6种,共计2科16属24种,占甘肃蛇类的75%。     

INCIDENTAL MORTALITY OF NORTHERN SEA LIONS IN SHELIKOF STRAIT, ALASKA

The incidental catch of northern sea lions ( Eumetopias jubatus ) in the walleye pollock ( Theragra chalcogramma ) joint-venture fishery in Shelikof Strait, Alaska, was studied during 1982–1984 to assess the nature and magnitude of the catch. Data were obtained by placing U.S. observers on foreign processing vessels. Dead sea lions recovered from trawl nets were counted, sexed and measured, teeth were removed for age determination by dental laminae; and stomach contents were analyzed. Although the fishery has continued to expand both in number of boats and estimated total catch (74,136 metric tons [t] in 1982 to 171,539 t in 1984), the estimated incidental catch of northern sea lions has declined (ranging from 958 to 1,436 in 1982, 216 to 324 in 1983 and 237 to 355 in 1984). Of the sea lions processed, 73 percent were caught between 2000 and 0500 h, probably during net retrieval. Most caught sea lions were females ranging in age from 1–25 yr with a mean age of 6.43 yr; 79 percent of the females were sexually mature and probably part of the reproducing population. Males had a mean age of 4.8 yr and only 12 percent were old enough to obtain and defend territories. Analysis of stomach contents showed that the sea lions consumed pollock the same size as that taken by the commercial fishery. The impact of the incidental catch on the Gulf of Alaska sea lion population is unknown.     

唐古拉山地区渐新世孢粉植物群及其古植被、古气候

唐古拉山地区广泛出露早新生代陆相地层,较好地记录了青藏高原北部新生代地质构造演化与古环境变迁的过程.通过在该区1:25万地质调查对雅西措组上段进行孢粉分析表明,孢粉组合以裸子植物花粉为主要成分,地质时代为早-中渐新世.在此基础上划分了3个孢粉植物群-气候期,当时植被是以松科植物为主组成的针叶林植被,从早期到中期喜湿热的蕨类植物和落叶阔叶树种增多;气候从凉爽湿润的南温带→半湿润偏干的北亚热带→偏干的南温带的转变.     

SENESCENCE IN NATURAL POPULATIONS OF MAMMALS: A COMPARATIVE STUDY

Here, I use published mortality data from 56 natural populations of mammals to examine evidence for senescence, an increase in the probability of mortality with age. Data on extent of senescence and life history characteristics are compared across taxa in an attempt to test theories for the evolution of senescence in natural populations. In accord with theoretical expectation, senescence is highest in short-lived species with short generation times. In contrast to theoretical expectation, however, senescent increases in mortality rate do not begin until well after age at maturity in most cases. I also present evidence in support of the hypothesis that senescence will be lower in large-brained taxa.     

PLANT DENSITY,CLEISTOGAMY, AND SELF-FERTILIZATION IN NATURAL POPULATIONS OF LITHOSPERMUM CAROLINIENSE

Lithospermum caroliniense has a heteromorphic incompatibility system complemented by self-compatibility via cleistogamy. Plants typically are either solely chasmogamic or solely cleistogamic. The percentage of cleistogamic plants in northern Illinois and Indiana populations varied from zero to 4.7. However, the percentage seed from self-fertilization varied from zero to 51.5, because cleistogamic plants produced 1.5 times as many ovules as chasmogamic plants, and the former type averaged 3.4 seeds per flower in contrast to 0.23 in chasmogamic flowers. Interpopulation differences in cleistogamy and self-fertilization were strongly correlated with plant density, an increase in density being accompanied by increases in the aforementioned features. Most populations had an excess of thrums, but there was no relationship between cleistogamic seed production and thrum:pin ratio.