Hanks Lawrence M, Paine Timothy D, Millar Jocelyn G, Campbell Christopher D, Schuch Ursula K
Department of Entomology, University of Illinois, 505 South Goodwin Ave., Urbana, IL 61801, USA e-mail:
Department of Entomology, University of California, Riverside, CA 92521, USA, , , , , , US.
Oecologia. 1999 May;119(3):400-407. doi: 10.1007/s004420050801.
Environmental stresses, particularly water deficit, predispose eucalypt trees to attack by the eucalyptus longhorned borer, Phoracantha semipunctata F. (Coleoptera: Cerambycidae). Our experiments with potted eucalypts revealed that reduced tree water potential was associated with lower resistance to colonization by neonate P. semipunctata, but the linear relationship between water potential and colonization success was reversed at higher larval densities. There was no indication that the bark exudate "kino" served to defend trees from borer attack. Larvae were not able to colonize the cambium of eucalypt logs with high bark moisture, and survival was low under high moisture conditions in artificial hosts composed of pure cellulose. In trees and cut logs with moist bark, larvae failed to reach the cambium, feeding instead in poorer-quality tissues just beneath the bark surface. Our findings suggest that variation in resistance of eucalypts to attack by the borer is associated with moisture content of the bark.
环境压力，尤其是水分亏缺，会使桉属树木更容易受到桉长角天牛（Phoracantha semipunctata F.，鞘翅目：天牛科）的侵害。我们对盆栽桉属植物进行的实验表明，树木水势降低与初孵的桉长角天牛定殖抗性降低有关，但在较高幼虫密度下，水势与定殖成功率之间的线性关系发生了逆转。没有迹象表明树皮渗出物“儿茶”能保护树木免受天牛的侵害。幼虫无法在树皮水分含量高的桉木原木形成层定殖，在由纯纤维素组成的人工寄主的高湿度条件下存活率很低。在树皮湿润的树木和伐倒原木中，幼虫无法到达形成层，而是在树皮表面下方质量较差的组织中取食。我们的研究结果表明，桉属植物对天牛侵害的抗性差异与树皮的含水量有关。
