@article{ErrardUlrichsKuehneetal.2015, author = {Errard, Audrey and Ulrichs, Christian and Kuehne, Stefan and Mewis, Inga and Drungowski, Mario and Schreiner, Monika and Baldermann, Susanne}, title = {Single- versus multiple-pest infestation affects differently the Biochemistry of Tomato (Solanum lycopersicum 'Ailsa Craig')}, series = {Journal of agricultural and food chemistry : a publication of the American Chemical Society}, volume = {63}, journal = {Journal of agricultural and food chemistry : a publication of the American Chemical Society}, number = {46}, publisher = {American Chemical Society}, address = {Washington}, issn = {0021-8561}, doi = {10.1021/acs.jafc.5b03884}, pages = {10103 -- 10111}, year = {2015}, abstract = {Tomato is susceptible to pest infestations by both spider mites and aphids. The effects of each individual pest on plants are known, whereas multiple-pest infestations have received little interest. We studied the effects of single-versus multiple-pest infestation by Tetranychus urticae and Myzus persicae on tomato biochemistry (Solanum lycopersicum) by combining a metabolomic approach and analyses of carotenoids using UHPLC-ToF-MS and volatiles using GC-MS. Plants responded differently to aphids and mites after 3 weeks of infestation, and a multiple infestation induced a specific metabolite composition in plants. In addition, we showed that volatiles emissions differed between the adaxial and abaxial leaf epidermes and identified compounds emitted particularly in response to a multiple infestation (cyclohexadecane, dodecane, aromadendrene, and beta-elemene). Finally, the carotenoid concentrations in leaves and stems were more affected by multiple than single infestations. Our study highlights and discusses the interplay of biotic stressors within the terpenoid metabolism.}, language = {en} } @article{KaechMatheHubertDennisetal.2018, author = {K{\"a}ch, Heidi and Mathe-Hubert, Hugo and Dennis, Alice B. and Vorburger, Christoph}, title = {Rapid evolution of symbiont-mediated resistance compromises biological control of aphids by parasitoids}, series = {Evolutionary applications}, volume = {11}, journal = {Evolutionary applications}, number = {2}, publisher = {Wiley}, address = {Hoboken}, issn = {1752-4571}, doi = {10.1111/eva.12532}, pages = {220 -- 230}, year = {2018}, abstract = {There is growing interest in biological control as a sustainable and environmentally friendly way to control pest insects. Aphids are among the most detrimental agricultural pests worldwide, and parasitoid wasps are frequently employed for their control. The use of asexual parasitoids may improve the effectiveness of biological control because only females kill hosts and because asexual populations have a higher growth rate than sexuals. However, asexuals may have a reduced capacity to track evolutionary change in their host populations. We used a factorial experiment to compare the ability of sexual and asexual populations of the parasitoid Lysiphlebus fabarum to control caged populations of black bean aphids (Aphis fabae) of high and low clonal diversity. The aphids came from a natural population, and one-third of the aphid clones harbored Hamiltonella defensa, a heritable bacterial endosymbiont that increases resistance to parasitoids. We followed aphid and parasitoid population dynamics for 3months but found no evidence that the reproductive mode of parasitoids affected their effectiveness as biocontrol agents, independent of host clonal diversity. Parasitoids failed to control aphids in most cases, because their introduction resulted in strong selection for clones protected by H.defensa. The increasingly resistant aphid populations escaped control by parasitoids, and we even observed parasitoid extinctions in many cages. The rapid evolution of symbiont-conferred resistance in turn imposed selection on parasitoids. In cages where asexual parasitoids persisted until the end of the experiment, they became dominated by a single genotype able to overcome the protection provided by H.defensa. Thus, there was evidence for parasitoid counteradaptation, but it was generally too slow for parasitoids to regain control over aphid populations. It appears that when pest aphids possess defensive symbionts, the presence of parasitoid genotypes able to overcome symbiont-conferred resistance is more important for biocontrol success than their reproductive mode.}, language = {en} }