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121.
Thomas Eisner Jeffrey Conner James E. Carrel John P. McCormick Amy J. Slagle Carl Gans James C. O'Reilly 《Chemoecology》1990,1(2):57-62
Summary Frogs(Rana pipiens) fed on blister beetles (Meloidae) or cantharidin, retain cantharidin systemically. After cessation of feeding, they void the compound relatively quickly. Systemic cantharidin does not protect frogs against ectoparasitic feeding by leeches(Hirudo medicinalis) or predation by snakes(Nerodia sipedon). As suggested by our data, and from reports in the early literature, ingestion of cantharidin-containing frogs can pose a health threat to humans.Paper no. 95 of the seriesDefense Mechanisms of Arthropods; no. 94 is LaMunyon & Eisner, Psyche (in press) 相似文献
122.
广东省水资源问题及可持续利用对策 总被引:7,自引:3,他引:7
论述了广东省的水资源状况和水资源利用中存在的主要问题,提出了水资源可持续利用的对策。认为水质性缺水、水利工程老化失修、水资源浪费严重、管理体制不健全是水资源利用中存在的主要问题;应加强水污染的防治,健全防洪防旱体系,建立健全水资源统一管理运作饥制,提高全民节水观念,发展节水农业,走兴林治水之路,使水资源可持续利用。 相似文献
123.
Akiko Matsumoto-Oda Miya Hamai Hitosige Hayaki Kazuhiko Hosaka Kevin D. Hunt Eiiti Kasuya Kenji Kawanaka John C. Mitani Hiroyuki Takasaki Yukio Takahata 《Behavioral ecology and sociobiology》2007,61(5):661-668
Although estrous synchrony has been reported in a number of mammalian species, most often among primates, methodological and
analytical problems make it difficult to interpret these results. We developed a novel estrous synchrony index and employed
a randomization procedure to analyze long-term observations of female chimpanzee (Pan troglodytes schweinfurthii) estrous cycles at the Mahale Mountains National Park, Tanzania. Our results revealed that female chimpanzees at Mahale avoid
synchronizing their estrous periods with each other. We also found that birthrates decreased as the breeding sex ratio increased.
We suggest that estrous asynchrony decreases female–female competition for mates. Asynchrony may also reduce the potential
for male sexual coercion by nonpreferred mating partners. 相似文献
124.
Managing mangroves in Bangladesh: A strategy analysis 总被引:1,自引:0,他引:1
Bangladesh, favoured by a tropical climate, houses the world’s largest stretch of mangroves forests (Sundarbans Reserved Forest)
and plantations. Around half of the forests of the country occur in the coastal zone. People extract various goods and services
from the mangroves. Nevertheless the mangrove forests are depleting. Although the extent of the Sundarbans forest has not
changed much, its decline is of a qualitative nature. Mangrove plantations are increasing in area but they are losing growing
stock. To arrest this, Bangladesh has adopted several strategies.
The ‘Sustainable Ecosystem Management’ strategy has now been adopted instead of the ‘Sustained Yield Principle’. Biodiversity
conservation and enhancement has been taken as a key management goal. A zoning system is being developed for both production
and protection purposes. The government facilitates alternative income for the local people by generating activities for the
communities which are dependent on the forest. Different non-governmental organizations collaborate with the government in
reducing the local people’s dependence on the forest. Coastal plantations are erected to protect people from cyclones and
to make the land more suitable for habitation. Through this greening of the coastal belt tree plantation is encouraged in
coastal villages. Coastal embankments are being planted and leased to poor settlers in exchange for routine maintenance of
the embankments. Plantations on newly accreted mud flats help in stabilizing the land, which can later on be settled by victims
of erosion elsewhere. These adopted management measures do not only contribute to forestry resource management but also to
the social, environmental and economic wellbeing of the coastal communities. These efforts are at present being integrated
into an Integrated Coastal Zone Management (ICZM) project. 相似文献
125.
126.
Peter Schausberger 《Behavioral ecology and sociobiology》2005,58(1):53-59
A crucial question with respect to imprinting is how animals ensure that kin imprint on kin but not on non-kin. Imprinting takes place in a sensitive ontogenetic phase, usually in an early period of life or when offspring are produced, at which time the recipient imprints on the first referents met. In the predatory mite Phytoseiulus persimilis, imprinting among immature individuals happens in the larval stage immediately after hatching. I tested the hypothesis that adult P. persimilis females manipulate offspring imprinting by influencing the likelihood of encounters among recipients and referents via egg placement and egg aggregation. I conducted two experiments, one of which addressed imprinting and cannibalism, and the other addressed egg placement and egg aggregation. The imprinting experiment suggests that larvae imprint on any conspecific individual met in a sensitive ontogenetic phase and later on treat this individual as kin, irrespective of relatedness. After molting to protonymphs, imprinted individuals preferentially cannibalized unfamiliar to familiar larvae. Irrespective of familiarity, kin were cannibalized earlier than non-kin, suggesting the involvement of self-referent phenotype matching. The egg-placement experiment provides evidence that females adjust the aggregation level of their own eggs according to the degree of relatedness to present eggs from a previously ovipositing female. Both experiments in concert suggest that egg placement is a maternal strategy influencing imprinting among immature individuals. Apart from avoiding kin cannibalism, egg placement and imprinting by larvae may have relevance to other behaviors influenced by kin recognition, such as mate choice, prey-patch choice and dispersal.Communicated by L. Simmons 相似文献
127.
128.
对于三峡工程没区文物群落的保护,不只限于其文物价值的研究,文物的保存环境及现状的评估更是采取科学保护方案的先决条件。从地面石抽文物的原位测试技术和地下文物的考古勘探技术两方面以实例和详细的数据,介绍了在三峡工程没区文物保护工程前 的科学 相似文献
129.
130.
本文详细论述了中国和世界的水资源状况,并论述了中国的水资源短缺状况、中国用水的优劣势,以及如何解决中国水资源短缺的措施和基本战略。 相似文献