白背飞虱的迁飞生物学:起飞与迁出

2001—2002年在苏州吴中区2个生长季节的田间观察和罩笼试验表明,白背飞虱Sogatella furcifera(Horváth)7月上旬以前迁入苏州,并在当地繁殖2代。从8月中下旬开始陆续有少量向外迁飞,9月份大田出现外迁高峰。田间白背飞虱起飞比率约为50%～65%,迁出峰期的每日迁出率约为80%。8月下旬白背飞虱一般已不构成危害。但20世纪90年代中期之后,白背飞虱8月份很少迁出而在迁入地大量滞留形成增殖代和主害代,危害时间大大延长,这与20世纪80年代的发生规律有了很大的不同。轨迹分析表明,8月中下旬从苏州迁出的个体中,40%可以到达江淮稻区,另有大约40%进入黄海和东海海域,若有强西南低空急流出现时则可跨海到达韩国和日本。9月份则主要是迁往我国的南方稻区,但很少可以直达岭南地区。

Migratory biology of the white backed planthopper:Take-off and emigration

The aerial migration of the white-backed planthopper Sogatella furcifera（Horváth）（WBPH） was studied in the field and captivity in Suzhou in 2001 and 2002.The results indicate that WBPH immigrate into Suzhou in early July,and produce two generation in this area.A few adults were beginning to emigrate from the end of August but the peak of emigration occurred in mid September when the mass flight could be seen at dusk.When the population density was high,the mass flight of insects continued until 10 minutes after twilight.The daily emigration ratio was about 80% during the emigration peak in captive populations,but about 50% to 65% in paddy fields.We found that the emigration behaviour of WBPH has changed since the mid 1990＇s.The offspring of immigrants would mostly emigrate when the macropterous adults emerged in 1980＇s,but now very few hoppers depart in August which greatly prolongs the duration of damage to rice crops.Emigration trajectory analysis at altitudes of 500,1 000 and 1 500 m indicates that in mid or late August about 40% of the migrating planthoppers from Suzhou arrive at the Yangtse and Huai River basin and the other 49% emigrate to the Yellow and East Seas,even crossing the sea to South Korea or Japan in a strong southerly low level jet-stream.In September,these planthoppers return to rice planting areas south of the Yangtse and north of Nanling.