Hatcher P E, Paul N D, Ayres P G, Whittaker J B
Division of Biology, Institute of Environmental and Biological Sciences, Lancaster University, Lancaster LAI 4 YQ, UK.
New Phytol. 1994 Sep;128(1):71-78. doi: 10.1111/j.1469-8137.1994.tb03988.x.
The chrysomelid beetle Gastrophysa viridula and the rust fungus Urmnyces rumicis both occur on leaves of Rumex crispus and R. obtusifolius. We investigated the effect of beetle grazing or rust infection individually and when combined in sequence on the growth of their hosts in the field. Singly, beetle or rust reduced leaf area and plant biomass; the effect was greater on R. crispus, and rust caused greater damage than the beetle. Beetle grazing with subsequent rust infection caused damage no greater than that caused by rust alone, although on R. obtusifolius damage was greater than that from beetle grazing alone. Rust infection of R. obtusifolius with subsequent beetle grazing produced damage similar to that from other treatments; involving rust infection. In R. crispus this treatment produced the greatest reduction in biomass, The reductions in root and total plant weight from rust infection with subsequent beetle grazing were accurately predicted by a model including the damage produced by beetle and rust alone and the length of time each was present on the plant. This model also predicted accurately the damage to R. obtusifolius from the beetle followed by rust treatment, but over-estimated by up to 40% the damage to R. crispus. This can be explained mainly by an inhibition of rust infection by beetle grazing.
叶甲科甲虫黄斑大叶甲和酸模单胞锈菌都寄生于皱叶酸模和钝叶酸模的叶片上。我们在田间研究了甲虫取食或锈菌感染单独作用以及二者先后联合作用对寄主植物生长的影响。单独来看，甲虫取食或锈菌感染都会减少叶面积和植物生物量；对皱叶酸模的影响更大，且锈菌造成的损害比甲虫更大。先经甲虫取食再感染锈菌造成的损害并不比仅由锈菌造成的损害更大，不过对于钝叶酸模，这种处理造成的损害比仅由甲虫取食造成的更大。先对钝叶酸模进行锈菌感染再让甲虫取食，造成的损害与其他涉及锈菌感染的处理类似；而对于皱叶酸模，这种处理使生物量减少得最多。通过一个模型可以准确预测先进行锈菌感染再让甲虫取食后根和整株植物重量的减少情况，该模型纳入了甲虫和锈菌单独造成的损害以及它们在植物上存在的时长。这个模型也能准确预测先让甲虫取食再进行锈菌处理对钝叶酸模造成的损害，但对皱叶酸模造成的损害高估了多达40%。这主要可以通过甲虫取食对锈菌感染的抑制作用来解释。
