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(Her)gebruik van digitale collecties in wetenschappelijk onderzoek: Dialecten op de kaart
No full textEvolutionary adaptation in three-way interactions between plants, microbes and arthropods
No full textSummary
Evolutionary adaptations in interactions between plants, microbes and arthropods are generally studied in interactions that involve only two of these groups, that is, plants and microbes, plants and arthropods or arthropods and microbes.
We review the accumulating evidence from a wide variety of systems, including plant- and arthropod-associated microbes, and symbionts as well as antagonists, that selection and adaptation in seemingly two-way interactions between plants and microbes, plants and arthropods and arthropods and microbes are often driven by the biotic context of a third partner.
We extend the concept of local adaptation from two-way interactions to scenarios for three-way interactions. We show that consumers can locally adapt to specific host phenotypes that are induced by a third species with which they do not directly interact. This emphasizes that indirect interactions have not only ecological but also important evolutionary consequences, and stresses the need to conduct studies of local adaptation in the proper ecological context of the species involved.
Overall, our review underlines the importance of three-way interactions in the evolution of plant–microbe, plant–arthropod and arthropod–microbe interactions, and we outline some promising directions for future research.
Getting the ecology into the interactions between plants and the plant-growth promoting bacterium Pseudomonas fluorescens
No full textPlant growth-promoting rhizobacteria (PGPR) are increasingly appreciated for their contributions to primary productivity through promotion of growth and triggering of induced systemic resistance in plants. Here we focus on the beneficial effects of one particular species of PGPR (Pseudomonas fluorescens) on plants through induced plant defense. This model organism has provided much understanding of the underlying molecular mechanisms of PGPR-induced plant defense. However, this knowledge can only be appreciated at full value once we know to what extent these mechanisms also occur under more realistic, species-diverse conditions as are occurring in the plant rhizosphere. To provide the necessary ecological context, we review the literature to compare the effect of P. fluorescens on induced plant defense when it is present as a single species or in combination with other soil dwelling species. Specifically, we discuss combinations with other plant mutualists (bacterial or fungal), plant pathogens (bacterial or fungal), bacterivores (nematode or protozoa), and decomposers. Synergistic interactions between P. fluorescens and other plant mutualists are much more commonly reported than antagonistic interactions. Recent developments have enabled screenings of P. fluorescens genomes for defense traits and this could help with selection of strains with likely positive interactions on biocontrol. However, studies that examine the effects of multiple herbivores, pathogens, or herbivores and pathogens together on the effectiveness of PGPR to induce plant defenses are underrepresented and we are not aware of any study that has examined interactions between P. fluorescens and bacterivores or decomposers. As co-occurring soil organisms can enhance but also reduce the effectiveness of PGPR, a better understanding of the biotic factors modulating P. fluorescens–plant interactions will improve the effectiveness of introducing P. fluorescens to enhance plant production and defense.
Noise annoys: effects of noise on breeding great tits depend on personality but not on noise characteristics
No full textAnthropogenic noise can have serious implications for animals, especially when they communicate acoustically. Yet, the impacts of noise may depend not only on noise characteristics but also on an individual's coping style or personality. We tested whether noise is more disturbing if it masks communication signals, and whether characteristics of both the noise and the individual affect its impact. Using a unique population of personality-typed great tits, Parus major, we tested whether the kind of noise and parental personality affect parental nestbox visits and nestling begging. Nestboxes were exposed to automated noise playbacks, differing in spectral composition (noise masking begging calls, nonmasking noise or no noise). Parental nestbox visits were recorded using RFID transponders. Video and audio recordings were used to quantify nestling begging. Nestlings mainly begged in silence and in the presence of parents. Parents reduced nestbox visits during noise treatments regardless of the kind of noise and initially reacted more strongly to nonmasking noise. Moreover, slower explorers took longer to enter the nestbox during noise than faster explorers. Total visit rates during noise depended on parental sex and personality. In females, bolder individuals, but in males shyer individuals, reduced total visits during noise. These results extend previous findings in showing experimentally that the disturbance effects of noise do not depend on whether or not the noise directly interferes with information exchange by masking signals. Moreover, personality- and sex-specific responses to noise indicate that anthropogenic disturbance can differentially affect individuals within populations, which will influence mitigation strategies.
A tritrophic approach to the preference–performance hypothesis involving an exotic and a native plant
No full text[KEYWORDS: Exotic invasive species Volatiles Plant preference–performance Host shift Multitrophic interactions Bunias orientalis]
Exotic plants often generate physical and chemical changes in native plant communities where they become established. A major challenge is to understand how novel plants may affect trophic interactions in their new habitats, and how native herbivores and their natural enemies might respond to them. We compared the oviposition preference and offspring performance of the crucifer specialist, Pieris brassicae, on an exotic plant, Bunias orientalis, and on a related native plant, Sinapis arvensis. Additionally, we studied the response of the parasitoid, Cotesia glomerata to herbivore-induced plant volatiles (HIPV) and determined the volatile blend composition to elucidate which compound(s) might be involved in parasitoid attraction. On both host plants we also compared the parasitism rate of P. brassicae by C. glomerata. Female butterflies preferred to oviposit on the native plant and their offspring survival and performance was higher on the native plant compared to the exotic. Although, headspace analysis revealed qualitative and quantitative differences in the volatile blends of both plant species, C. glomerata did not discriminate between the HIPV blends in flight-tent bioassays. Nevertheless, parasitism rate of P. brassicae larvae was higher on the native plant under semi-field conditions. Overall, P. brassicae oviposition preference may be more influenced by bottom-up effects of the host plant on larval performance than by top-down pressure exerted by its parasitoid. The potential for dietary breadth expansion of P. brassicae to include the exotic B. orientalis and the role of top-down processes played by parasitoids in shaping herbivore host shifts are further discussed.
The effect of phosphorus binding clay (Phoslock®) in mitigating cyanobacterial nuisance: a laboratory study on the effects on water quality variables and plankton
Get PDFGenetic engineering of plant volatile terpenoids: effects on a herbivore, a predator and a parasitoid
No full textBACKGROUND: Most insect-resistant transgenic crops employ toxins to control pests. A novel approach is to enhance the effectiveness of natural enemies by genetic engineering of the biosynthesis of volatile organic compounds (VOCs). Before the commercialisation of such transgenic plants can be pursued, detailed fundamental studies of their effects on herbivores and their natural enemies are necessary. The linalool/nerolidol synthase gene FaNES1 was constitutively expressed from strawberry in three Arabidopsis thaliana accessions, and the behaviour of the aphid Brevicoryne brassicae L., the parasitoid Diaeretiella rapae McIntosh and the predator Episyrphus balteatus de Geer was studied.
RESULTS: Transgenic FaNES1-expressing plants emitted (E)-nerolidol and larger amounts of (E)-DMNT and linalool. Brevicoryne brassicae was repelled by the transgenic lines of two of the accessions, whereas its performance was not affected. Diaeretiella rapae preferred aphid-infested transgenic plants over aphid-infested wild-type plants for two of the accessions. In contrast, female E. balteatus predators did not differentiate between aphid-infested transgenic or wild-type plants.
CONCLUSION: The results indicate that the genetic engineering of plants to modify their emission of VOCs holds considerable promise for facilitating biological control of herbivores. Validation for crop plants is a necessary next step to assess the usefulness of modified volatile emission in integrated pest management.
