Fuentes-Contreras Edurado, Pell Judith K, Niemeyer Hermann M
Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile e-mail:
Entomology and Nematology Department, IACR-Rothamsted, Harpenden, Herts, AL5 2JQ, UK, , , , , , GB.
Oecologia. 1998 Dec;117(3):426-432. doi: 10.1007/s004420050677.
Host-plant resistance can affect herbivorous insects and their natural enemies such as parasitoids and entomopathogenic fungi. This tritrophic effect acts on interspecific interactions between the two groups of natural enemies distantly related in phylogenetic terms. The intra- and extra-host aspects of the interaction between the cereal aphid parasitoid Aphidius rhopalosiphi and the entomopathogenic fungus Erynia neoaphidis developing on the grain aphid, Sitobion avenae, on resistant and susceptible wheat (Triticum aestivum) cultivars, were studied. The competitive outcome of the intra-host interaction depended on the timing of parasitoid oviposition and fungal infection and was affected by wheat resistance. In particular, survival of the parasitoid was lower on the resistant wheat cultivar than the susceptible wheat cultivar, when the competitive outcome of the interaction was favourable for either parasitoid or fungal development. Before and after this period the influence of plant resistance was not significant. Furthermore, the extra-host interaction was not affected by the wheat cultivar, although an increase in fungal infection of S. avenae was observed when parasitoids foraged in the experimental arena with sporulating aphid cadavers compared with foraging in the absence of sporulating cadavers. Our results showed that the host plant may affect interspecific interactions between parasitoids and fungi and that these interactions depended on the timing of parasitoid oviposition and fungal infection.
寄主植物抗性会影响植食性昆虫及其天敌，如寄生蜂和昆虫病原真菌。这种三级营养效应作用于系统发育关系较远的两类天敌之间的种间相互作用。我们研究了谷物蚜虫寄生蜂麦长管蚜蚜茧蜂与在禾谷缢管蚜上发育的昆虫病原真菌新蚜虫疠霉之间在抗性和敏感小麦（普通小麦）品种上的寄主内和寄主外相互作用。寄主内相互作用的竞争结果取决于寄生蜂产卵时间和真菌感染时间，并受小麦抗性影响。具体而言，当相互作用的竞争结果对寄生蜂或真菌发育有利时，寄生蜂在抗性小麦品种上的存活率低于敏感小麦品种。在此期间之前和之后，植物抗性的影响不显著。此外，寄主外相互作用不受小麦品种影响，不过与在没有产孢蚜虫尸体的情况下觅食相比，当寄生蜂在有产孢蚜虫尸体的实验区域觅食时，观察到禾谷缢管蚜的真菌感染有所增加。我们的结果表明，寄主植物可能会影响寄生蜂和真菌之间的种间相互作用，且这些相互作用取决于寄生蜂产卵时间和真菌感染时间。
