光照、温度对光滑足距小蠹雌成虫起飞行为的影响

光滑足距小蠹Xylosandrus germanus(Blandford)]雌成虫具有明显的趋光性,光照强度为1~400 lx时,趋光性随光照强度提高而增强。25℃时,完全黑暗条件下该小蠹雌成虫不起飞,光照强度为1~1 500 lx时,起飞虫量随光照强度的增加而增加,且起飞虫量在光照强度为1 500 lx时达最大,光照强度超过1 500 lx时,起飞虫量又逐渐减少。在光照强度400 lx、温度21℃时雌成虫开始起飞,温度21~30℃,起飞虫量随温度升而增加,温度为25~27℃时起飞虫量较多,温度升至35℃时,小蠹雌成虫停止飞行。研究表明,光照和温度两个因素中,温度是光滑足距小蠹雌成虫起飞的先决条件,只有当环境温度高于起飞的临界温度(21℃)时,在低光照强度下雌成虫才起飞。

The Influence of Temperature and Light on the Taking off of Xylosandrus germanus(Blandford)(Coleoptera:Scolytidae)

Take-off activity of the female adults of Xylosandrus germanus,the ambrosia beetle,was studied in lab.A relative remarkable phototaxis of the beetle was proved.In the region of light intensity between 1～400 lx,the phototaxis of the beetle increased with light intensity.At temperature of 25 ℃,no beetle took off in the dark,the rate of take-off of the female adults was increased with light intensity in the region of light intensity between 1～1 500 lx and 1 500 lx for maximum flight.At light intensity of 400 lx,the rate of take-off of the beetle increased with temperature in the region of temperature 21～30 ℃,21 ℃ was minimum for flight and 25～27 ℃ for maximum flight,while flight activity ceased at temperatures over 35 ℃.These results showed that the female adults preferred low light intensity for flight,the threshold temperature necessary for flight was 21 ℃,and temperature was prerequisite for flight initiation.