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141.
The Science of Nature - Morphological indications and new experimental results demonstrate that neurosecretory peptides or low-molecular proteins, respectively, appear to effect as mediators in... 相似文献
142.
Patricia L. Jones Rachel A. Page Manfred Hartbauer Bj?rn M. Siemers 《Behavioral ecology and sociobiology》2011,65(2):333-340
Eavesdropping on prey communication signals has never before been reported for a Palearctic bat species. In this study, we
investigated whether lesser and greater mouse-eared bats, Myotis blythii oxygnathus and Myotis myotis, find tettigoniid bushcrickets (Tettigoniidae) by eavesdropping on their mate-attraction song. Tettigoniids are known to
be the most important prey item for M. blythii oxygnathus, while carabid beetles and other epigaeic arthropods are the most important prey for its sibling species, M. myotis, in many places in Europe. M. myotis locates walking beetles by listening for their rustling sounds. We compared these two species’ response to four acoustic
prey cues: calling song of two tettigoniid species, the rustling sound made by walking carabid beetles, and a control tone.
Individuals of both bat species attacked the speaker playing tettigoniid song, which clearly indicates that both species eavesdrop
on prey-generated advertisement signals. There were, however, species differences in response. M. blythii oxygnathus exhibited stronger predatory responses to the calling song of two species of tettigoniid than to the beetle rustling sound
or the control. M. myotis, in contrast, exhibited stronger predatory responses to the beetle rustling and to one tettigoniid species but not the other
tettigoniid or the control. Our study (1) for the first time demonstrates eavesdropping on prey communication signals for
Palearctic bats and (2) gives preliminary evidence for sensory niche partitioning between these two sympatric sibling bat
species. 相似文献
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The populations of European great cormorants (Phalacrocorax carbo) and North American double-crested cormorants (Phalacrocorax auritus) have increased sharply over the last decades and these piscivorous birds are suspected to deplete valuable fish stocks and
compete with human fisheries. Beyond direct consumption of fish, cormorants are accused of injuring vast numbers of prey without
eating them. Using underwater video systems, one of them mounted onto the back of tame Chinese cormorants, we evaluated the
proportion of successful pursuits of cormorants on live fish. Trials were conducted with 6 great cormorants and 9 double-crested
cormorants and involved a total of 676 prey pursuits. We show that, although they are regarded as highly efficient predators,
cormorants aborted about half of their pursuits. However, detailed analysis of prey-capture behaviour in double-crested cormorants
revealed that only 0.4% of the prey pursued was injured without being ingested. Further studies using miniature video systems
deployed on free-ranging cormorants are required to complement our knowledge of their hunting tactics. 相似文献
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The theory of self-reproductive molecular systems involves the consequence that translation must have started from a selected distribution of RNA molecules, that comprised GC-rich sequences of a length < 100 nucleotides. This implies a joint function of messenger and adaptor, which both had to be recruited from the same mutant distribution. The reconstruction of tRNA precursors yields such a molecule showing some reverberation of a codon pattern GNC. These findings suggest that tRNA has been the earliest component of the translation machinery. 相似文献
147.
Manfred Schidlowski 《Die Naturwissenschaften》1969,56(10):488-493
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