加拿大科迪勒拉页岩型铅锌矿床的平均铅同位素生长曲线

<正> 如果将Stacey和Kramers(1975)或Cumming和Richards(1975)的模型作为计算模型年龄的基础,那么加拿大科迪勒拉(图1)古生代页岩型矿床的方铅矿-铅同位素(表2)将给出不真实的年轻的年龄。可是,赫利克到泥盆-密西西比期矿床的这些相同的同位素数据在图2和图3的~(208)Pb/~(204)Pb-~(206)Pb/~(204)Pb或~(207)Pb/~(204)Pb-~(206)Pb/~(204)Pb图上却形成独特的组,并且按年龄形成有规律的排列。页岩型矿床(图1)中所有这些同位素数据以这样一种方式作图,是为了表明类似地壳     

Low chitinase activity in Acacia myrmecophytes: a potential trade-off between biotic and chemical defences?

 We determined chitinase activity in leaves of four myrmecophytic and four non-myrmecophytic leguminous species at the plants' natural growing sites in Mexico. Myrmecophytic plants (or 'ant plants') have obligate mutualisms with ants protecting them against herbivores and pathogenic fungi. Plant chitinases can be considered a reliable measure of plant resistance to pathogenic fungi. The myrmecophytic Acacia species, which were colonised by mutualistic ants, exhibited at least six-fold lower levels of chitinase activity compared with the non-myrmecophytic Acacia farnesiana and three other non-myrmecophytes. Though belonging to different phylogenetic groups, the myrmecophytic Acacia species formed one distinct group in the data set, which was clearly separated from the non-myrmecophytic species. These findings allowed for comparison between two recent hypotheses that attempt to explain low chitinase activity in ant plants. Most probably, chitinases are reduced in myrmecophytic plant species because these are effectively defended indirectly due to their symbiosis with mutualistic ants. Received: 16 August 2000 / Accepted in revised form: 28 October 2000     

Epicuticular wax of large and small white butterflies,<Emphasis Type="Italic"> Pieris brassicae</Emphasis> and<Emphasis Type="Italic"> P. rapae crucivora</Emphasis>: qualitative and quantitative comparison between diapause and non-diapause pupae

We compared the quantity and quality of the epicuticular wax of diapause and non-diapause pupae in two closely related Pieris species, P. brassicae and P. rapae crucivora. Main components of their epicuticular wax were identified as hydrocarbons. In P. brassicae, more than 95% of hydrocarbons were saturated regardless of whether the pupae were in diapause or not. In P. rapae crucivora, 93% of hydrocarbons were saturated in non-diapause pupae whereas in diapause pupae 41% were saturated and 59% unsaturated. From measurements of body surface area by nuclear magnetic resonance microimaging, we calculated the average thickness of the wax layer. The thickness in diapause and non-diapause pupae of P. brassicae was 800 and 160 nm, respectively. In P. rapae crucivora, the thickness was 195 nm in diapause and 11 nm in non-diapause. This is the first report to clarify the compositional difference in epicuticular wax between diapause and non-diapause pupae.     

论米尔加里萨矿床的成因

<正> 包括米尔加里萨铅-锌矿床在内的层控多金属矿床的成因问题,引起了很多研究者的注意。一些人认为这类矿床属于热液(超低温)型,另一些人则认为是成岩或变质作用阶段经过改造的原始沉积成因矿床。     

Monogamy in a new species of wild guinea pigs (Galea sp.)

A new species of wild guinea pigs from Bolivia was recently discovered: Galea sp. So far no data are available concerning its social and mating systems. We therefore investigated behavioural compatibility, sexual dimorphism, paternity in a male-competing situation, testicular and epididymal size, and sperm morphology and motility. The results showed a complete intrasexual and moderate intersexual behavioural incompatibility between unfamiliar animals, a reversed sexual dimorphism with females larger than males, and litters always fathered by single males. Furthermore, both the reproductive organ weights and the percentage of motile sperm and sperm with intact acrosomes were significantly lower compared with the promiscuous congeneric Galea musteloides. In summary, these data strongly suggest a monogamous social and mating system for the recently discovered Galea sp.     

A new C12 alcohol identified as a sex pheromone and a trail-following pheromone in termites: the diene (<Emphasis Type="Italic">Z</Emphasis>,<Emphasis Type="Italic">Z</Emphasis>)-dodeca-3,6-dien-1-ol

The diunsaturated C12 alcohol (Z,Z)-dodeca-3,6-dien-1-ol (dodecadienol) has been characterized by GC-MS and FTIR as a novel releaser pheromone in termites. This alcohol identified in Ancistrotermes pakistanicus (Termitidae, Macrotermitinae) possesses a double pheromonal function which again illustrates the chemical parsimony of termites compared with other social insects. In workers, dodecadienol elicits trail-following at a very low concentration (activity threshold at 0.1 pg/cm of trail); in male alates it induces trail-following at a low concentration (1–10 pg/cm) and sexual attraction at a higher concentration (about 1 ng). Traces of the monounsaturated C12 alcohol (Z)-dodec-3-en-1-ol (dodecenol), known as a trail pheromone of several Macrotermitinae, were also found in the sternal gland extracts of A. pakistanicus, although only dodecadienol was present at the surface of the sternal gland. Workers of A. pakistanicus are not sensitive to dodecenol, but they are as sensitive to dodecatrienol as to dodecadienol. However, in the study area (Vietnam), A. pakistanicus is living in sympatry only with those Macrotermitinae using dodecenol as a trail pheromone, the foraging populations therefore being well isolated through their respective trail pheromones. The presence of three types of unsaturated C12 alcohols as releaser pheromones in the only Macrotermitinae subfamily is discussed, and a possible biosynthetic pathway from linoleic acid is proposed for dodecadienol.     

A unique strategy of host colony exploitation in a parasitic ant: workers of<Emphasis Type="Italic"> Polyrhachis lama</Emphasis> rear their brood in neighbouring host nests

The formicine ant Polyrhachis lama is a social parasite, exploiting its ponerine host ant species Diacamma sp. In most social parasitic associations, the parasitic species are closely related to their host species group, evolving directly from independent ancestors of the host species. However, in the Polyrhachis lama–Diacamma sp. association, the associated species belong to different ant subfamilies. Based on preliminary field surveys, we had presumed that P. lama might have given up its reproductive division of labour, i.e. workers would be able to produce males as well as workers and females parthenogenetically. In this study, this hypothesis was disproved: Polyrhachis lama workers cannot be fertilized and are only able to produce males. In the host–parasite association originating from nests possessing a P. lama queen, workers penetrate surrounding Diacamma sp. nests, carrying brood for rearing within these satellite nests. In this peculiar way, a single P. lama colony is able to exploit several Diacamma sp. colonies simultaneously.     

Attraction of the tropical bont tick,Amblyomma variegatum,to human breath and to the breath components acetone,NO and CO2

Ticks are of medical and veterinary importance and employ several cues in search of a host. Olfaction is one modality by which ticks locate a blood-meal and breath is the major vent of gaseous and volatile metabolites from the host that could contribute to this search. We studied the responses of a hunter tick, Amblyomma variegatum, to diluted human breath and five of its components (acetone, CO₂, NO, isoprene and NH₃) while walking in an air stream on a locomotion compensator. Diluted breath elicited the greatest responses of all treatments in terms of time to onset of upwind walk, attraction, speed and local search behaviour after stimulus off. Acetone, NO and CO₂ also attracted, but with a reduced speed in the case of acetone and NO. Neither isoprene nor NH₃ induced any response. Our study indicates that breath was the most adequate stimulus tested. It also attracted two other ixodid tick species, Rhipicephalus sanguineus and Ixodes ricinus, as well as the argasid tick, Ornithodorus moubata. It appears that the evolution of resource tracking in ticks included sensory and behavioural adaptations for recognition and orientation to host metabolites that are regularly expelled in breath.     

印度更安全的有害材料道路运输：实践中的TransAPELL

由于地域辽阔，消费市场大，化学工业范围广泛，安全是印度工业和政府最大的担忧，自1992年启动第一个“地方级应急意识与准备”（APELL）项目以来，印度在加强有害材料运输和处理安全方面取得了很大进展．本文着重介绍了为解决这一领域最为追切的安全问题而开展的行动和项目。     

促进泰国清洁生产：清洁生产与ISO14001环境管理系统的一体化

清洁生产计划和环境管理系统（其中ISO14000EMS系列将成为国际标准）已被确认为促进泰国工业污染削减的潜在强有力手段．本文考察了清洁生产方法和ISO14001EMS方法，以确定两者之间的可能关系，以及ISO14001对促进泰国清洁生产的潜在影响．