寄主挥发物、叶色在B型烟粉虱寄主选择中的作用

在室温条件下,研究B型烟粉虱Bemisia tabaci(Gennadius)对不同寄主植物和颜色的行为趋性。笼罩实验的结果显示,烟粉虱雌虫对共存的5种寄主植物偏好存在显著差异,总体上表现为对番茄的趋性最强(35·0%),甘蓝次之(27·7%),烟草和棉花再次之,辣椒最低(7·1%);且随着时间的延长,烟粉虱数量在番茄上逐渐增加,在甘蓝上呈下降趋势,在烟草、棉花和辣椒上变动幅度不大,但数量总体上仍是番茄(48·8%)>甘蓝(18·4%)>烟草、棉花>辣椒(3·4%)。但烟粉虱在不同寄主植物上的产卵量则表现为:甘蓝>番茄>棉花、烟草>辣椒;其中甘蓝和番茄上卵量分别占总卵量的56·8%和28·2%;而烟草、棉花和辣椒上的卵量均不到总卵量的6·0%。"Y"型嗅觉仪进一步测定表明:寄主植物番茄和甘蓝气味对烟粉虱具有显著引诱作用,且表现为番茄>甘蓝,辣椒不具引诱作用;烟粉虱对3种植物(番茄、甘蓝、辣椒)的叶片颜色均有显著趋性,选择率在75%左右,但在三者之间的趋性差异不明显;烟粉虱雌虫对黄色和绿色均具有显著趋性,且对黄色的趋性显著大于对绿色的趋性,但对红色无趋性。综合分析表明,在对寄主定向和定位过程中,B型烟粉虱的视觉和嗅觉均起作用,但在对同种颜色(绿色)的寄主进行选择和定位的过程中,嗅觉起主要作用,而对不同种颜色(红、黄、绿)的选择和定位时,其视觉起决定作用。

Behavior selection of Bemisia tabaci B-biotype to different host plants and colors

Effect of different plant species and colors on host preference of Bemisia tabaci (Gennadius) B-biotype was studied in the present study. The quantity of adults and eggs per plant on five species of host plants were assessed in selection test in a cage, the results revealed that significantly different host preference of female adults was present in different plants. The preference order was tomato>cabbage>pepper>tobacco and cotton>pepper. With the time going, the amount of adults in tomato increased gradually, and that in cabbage decreased, whereas no dramatic change occurred in tobacco and cotton. Eggs B. tabaci B-biotype layed in different host plants were cabbage>tomato>cotton, and tobacco>pepper, and egg production in cabbage and tomato respectively accounted for 56.8% and 28.2% number of total eggs, whereas that in tobacco, cotton and pepper all accounted for less than 6.0% number of total eggs. Furthermore, a Y-tube olfactometer was used to test the role of volatiles from host plants and colors in host selection by B. tabaci. It was found that odors of tomato and cabbage showed significant attractiveness to B. tabaci, odors of tomato being more attractive; but odors of pepper had no attractiveness to B. tabaci. The green leaves of tomato, cabbage and pepper all showed significant attractiveness to B. tabaci adults, and no significant difference existed in the three plants. B tabaci adults could be attracted by green and yellow color but not by red color. When B. tabaci were faced with both green and yellow color at the same time, they were more attracted by yellow than by green. All results above-mentioned indicated that both vision and olfaction of B. tabaci played important roles in host orientation and selection; olfaction was crucial to host orientation and selection of green hosts, and vision was crucial to host orientation and selection of red, green and yellow hosts.