摘要
不同地理种群松毛虫的临界光周值与其所在地的纬度有密切关系。松毛虫光照周期反应的敏感虫期随地理纬度变化而变化。不同地理种群的松毛虫滞育强度也明显不同。光照周期反应是北方松毛虫世代和长江沿岸地区松毛虫二、三代分化的关键因子,当自然界光周值与当地松毛虫的临界光周值相同时,此日期即为当地松毛虫种群分化的临界日。在二、三代地区,临界分化日和幼虫的发育进度决定了当地松毛虫二、三代分化的比例。当温度变化时,其临界日也会随之发生变化。本文还对安徽东至金寺山林场松毛虫的危害情况和二、三代分化及其原因进行了讨论。
The geographic variation of photoperiodic response was studied in the pine caterpillar (Dendrolimus spp., in short: pc) at latitudes from 29.4 to 39.8 °N in China. The result demonstrated that the critical photo- period for diapause induction observed at 27~28℃ was 14 h 30 min for Beijing strain (39.8°N), 14 h 2 min for Jincheng (35.5°N, Shanxi Province) and 13 h 24 min for Yongchuan (29.4 °N, Sichuan Province). The critical phot-operiod increases about 30 min for each increase in latitude of 5°N.Sensitivity of pc to photoperiod during the larval stage varied with age and latitude. The overwinter larvae originated from North China displayed a stronger diapause and can usually survive a longer period under 28℃ but those originated from the South showed a weaker diapause and can only survive a shorter period at the same temperature.It was revealed that photoperiodic diapause is the key factor to control the differentiation of generation in pc. Under shortdays condition, the larvae entered diapause in the third and fourth instar and were unable to continue development without terminating diapause even under a high temperature condition. When the natural photoperiod exposed to the larvae equal to its critical photoperiod the day reaches the critical point (date) of differentiation. The critical date plays a decisive role to determine the ratio of differentiation of pc. Moreover, temperature and nutrition can modify the ratio by affecting the critical date. The larvae hatched before the critical date can produce one generation more than those hatched after the critical date.In this paper, the relation between the enviromental factors and the ratio of the third generation of pc was discussed in Jinsishan Forest Farm (in Anhui Province).
出处
《林业科学研究》
CSCD
北大核心
1993年第1期52-57,共6页
Forest Research
关键词
松毛虫
光周期
反应
Dendrolimus, geographical variation, differentiation of generation, critical date of differentiation, critical photoperiod
