科研之友
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摘要
The altitudinal variation of the demographic structure in populations of Poecilusfortipes (Chaud.) based on the results obtained in four mountain localities of southern Eastern Siberia are discussed, and the life cycle is reconstructed for each of them. The size of both males and females decreased along the altitudinal gradient. The beetles from the Selenga middle mountains (600-650 m a.s.l.) were much larger, while the beetles at the upper boundary of the forest-steppe belt in the Eastern Sayan (1500-1700 m a.s.l.) were smaller than the other ones. The linear dimensions decreased more distinctly in the zone transitional between midlands and highlands. The duration of reproduction was independent of the altitude. However, along the altitudinal gradient, the laying period was shifted to the beginning of growing season, because its duration was reduced, and the sum of effective temperatures decreased. With increasing the altitude, the average number of eggs per female was significantly reduced from 15.9 +/- 6.1 to 8.6 +/- 5.8, whereas the maximum number of eggs increased from 26-28 to 40-43. On the contrary, the terms of adult emergence were gradually shifted from the early mid of growing season to its mid end. The populations from the Selenga middle mountains, the Vitim Plateau, and at the lower border of the forest-steppe belt in the Eastern Sayan were characterized by a relatively low catch index and a lack of rebreeding old individuals. Both these facts increase the risk of unprompted extinction of local populations. Along the altitudinal gradient, the annual life cycle with summer breeding in populations of P. fortipes was replaced by an obligate biennial life cycle with summer and early-summer breeding. The transition from the annual development to the biennial one was observed with increasing the altitude from 600-650 m to 900-950 m a.s.l. The sum of effective temperatures (up to 1400 degrees C) was not enough to implement the annual life cycle.
- 出版日期2013-10
