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A life-history perspective on strategic mating effort in male scorpionflies   总被引:3,自引:1,他引:2  
In species with high male mating effort, there is a trade-offbetween mating effort spent in a current mating and resourcesleft for future matings. Consequently, to maximize their reproductivesuccess, males have to invest strategically, saving resourcesin matings with low reproductive gain for future, more valuablematings. However, as males age, the expected future reproductivesuccess constantly declines. Thus, the importance of resource rationing may drastically change during a lifetime. Males ofthe scorpionfly Panorpa cognata offer females a costly nuptialgift before copulation, which functions as male mating effort.Resources for the production of these salivary masses are severelylimited for males in poor condition. We found that males investedmore in copulations with high-quality females than in copulationswith low-quality females. However, males ceased to discriminateas they became older. Old males, with a relative small numberof expected future matings, did not invest differentially incopulations with high- versus low-quality females. In copulationswith low-quality females, males invested more in late thanin initial matings, whereas in matings with high-quality females,time of mating had no influence on mating effort. These resultsimply that males adaptively change their resource allocationstrategy during the course of the season. Initial matings seemto be characterized by male prudence; in later matings, malesseem to adopt a more opportunistic mating strategy.  相似文献
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There are very few investigations of cold hardiness in native Australian insects, and no such studies on insects from Tasmania. The Apteropanorpidae is a family of wingless Mecoptera endemic to Tasmania, comprising four described species that can be active in winter. In this study, we used infrared video thermography to investigate the physiological and behavioural responses of Apteropanorpa tasmanica to fast (0.3 degrees Cmin(-1)) and slow (0.03 degrees Cmin(-1)) rates of temperature reduction down to -10 degrees C. No adults survived cooling to -10 degrees C at either cooling rate. Mean supercooling points (SCPs) from fast cooling were -7.0 and -4.6 degrees C in 2002 and 2003, respectively. Ice nucleation always began in the abdomen, however, the position of nucleation within the abdomen varied between individuals. There was no relationship between SCP and body length, and no significant difference in SCPs between males and females. Stress-induced fast walking began when insects reached approximately -1.5 degrees C. Cooling rate did not affect the SCP or the temperature at which the behavioural stress response began. Adults survived for only short periods of time in the supercooled state; however they survived in the laboratory for up to 60 days at 4 degrees C, indicating their longevity at more favourable temperatures. Members of the Apteropanorpidae are adapted to the relatively warm, maritime climate currently influencing Tasmania.  相似文献
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Two new species and a new genus of scorpionflies of the family Kaltanidae, Pseudochorista occidentalis sp. nov. and Kamochorista novokshonovi gen. et sp. nov. (Mecoptera: Kaltanidae), are described from the Urzhumian of Udmurtia (Chepanikha locality). This is the first record of kaltanids on the Russian Platform.  相似文献
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长翅目昆虫在地史纪录上可以追溯到早二叠纪,是全变态昆虫中最原始的种类之一.截至目前,29篇关于中国长翅目昆虫化石分类的论著发表,共描述我国长翅目昆虫化石11科28属51种,这些化石分布于从三叠纪到白垩纪的不同地层中.本文通过图表提供了我国已发现的长翅目化石名录并介绍了其分布和年代,回顾了我国长翅目昆虫化石的研究进展,指出了一些分类存在的问题,简要慨述了长翅目中一些科的起源与演化以及长翅目与其它全变态昆虫的关系.我国长翅目化石种类丰富,但在基础分类、系统演化方面还缺乏系统的研究,因而许多工作甚至最基础的分类工作亟待开展.  相似文献
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