Kompetenzzentrum für Biodiversität und integrative Taxonomie (KomBioTa)

Permanent URI for this collectionhttps://hohpublica.uni-hohenheim.de/handle/123456789/79

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Complementary effects of pollination and biocontrol services enable ecological intensification in macadamia orchards
(2024) Anders, Mina; Westphal, Catrin; Linden, Valerie M. G.; Weier, Sina; Taylor, Peter J.; Grass, Ingo
In many crops, both pollination and biocontrol determine crop yield, whereby the relative importance of the two ecosystem services can be moderated by the landscape context. However, additive and interactive effects of pollination and biocontrol in different landscape contexts are still poorly understood. We examined both ecosystem services in South African macadamia orchards. Combining observations and experiments, we disentangled their relative additive and interactive effects on crop production with variation in orchard design and landscape context (i.e., cover of natural habitat and altitude). Insect pollination increased the nut set on average by 280% (initial nut set) and 525% (final nut set), while biocontrol provided by bats and birds reduced the insect damage on average by 40%. Pollination services increased in orchards where macadamia tree rows were positioned perpendicular to orchard edges facing natural habitat. Biocontrol services decreased with elevation. Pest damage was reduced by higher cover of natural habitat at landscape scale but increased with elevation. Pollination and biocontrol are both important ecosystem services and complementary in providing high macadamia crop yield. Smart orchard design and the retention of natural habitat can simultaneously enhance both services. Conjoint management of ecosystem services can thus enable the ecological intensification of agricultural production.
Complex European invasion history of Anoplophora glabripennis (Motschulsky): new insights in its population genomic differentiation using genotype-by-sequencing
(2024) Haeussermann, Iris; Hasselmann, Martin
Anthropogenic activities like trade facilitate increasing rates of biological invasions. Asian long-horned beetle (ALB), which is naturally distributed in eastern Asia (China, Korean peninsula), was introduced via wood packing materials (WPM) used in trade to North America (1996) and Europe (2001). We used 7810 single nucleotide polymorphisms (SNPs) derived by a genotype-by-sequencing (GBS) approach to decipher the introduction patterns into Europe. This is applied for the first time on European ALB outbreaks from Germany, Switzerland, and Italy, both from still active and already eradicated infestations. The genome-wide SNPs detected signs of small and highly structured populations within Europe, showing clear founder effects. The very high population differentiation is presumably derived from multiple independent introductions to Europe, which are spatially restricted in mating. By admixture and phylogenetic analyses, some cases of secondary dispersal were observed. Furthermore, some populations suggest admixture, which might have been originated by either multiple introductions from different sources into the new sites or recurrent introductions from an admixed source population. Our results confirmed a complex invasion history of the ALB into Europe and the usability of GBS obtained SNPs in invasion science even without source populations.
Mineral-ecological cropping systems mitigate biodiversity-productivity trade-offs of the organic vs. conventional farming dichotomy
(2024) Kasten, Marit Kinga; Witte, Felix; Sponagel, Christian; Bahrs, Enno; Köhler, Thomas; Morinière, Jérôme; Grass, Ingo
Conventional agriculture significantly reduces biodiversity, while organic farming promotes it, but often yields half as much. Addressing this biodiversity-productivity trade-off is crucial for future agriculture. Mineral-ecological cropping systems (MECS) have been suggested as an alternative, blending organic and conventional methods by avoiding chemical-synthetic pesticides and using mineral fertilizers. In a German experiment with 168 parcels, we compared MECS, conventional, and organic systems in terms of ecological and economic performance. Arthropod diversity was measured through standardized species collections and DNA-metabarcoding. Productivity was assessed via yields and economic profits. MECS showed similar arthropod diversity to other farming systems, achieved 90% of conventional crop yields, and produced 1.8 times of the organic yield. Profits from MECS were on average 37% higher than the conventional system with a short wheat-maize-soy crop rotation. Further farm-level studies are needed, but MECS could be a reasonable alternative to both organic and conventional farming and can mitigate biodiversity-productivity trade-offs.
The potential of farnesene isomer mixtures to support the control of aphids in the cultivation of lettuce crops
(2025) Kuhn, Denise; Bauer, Philipp; Tolasch, Till; Petschenka, Georg; Steidle, Johannes L. M.
(E)-ß-farnesene (EBF) acts as an alarm pheromone of many aphid species and is also used as an aphid repellent by plants. Upon perception of EBF, aphids exhibit avoidance behavior. They walk away, stop feeding or drop from leaves. Moreover, EBF is an attractant for natural enemies of aphids. However, EBF is not used in pest management because it is expensive in its pure form. Therefore, we assessed the effect of a less expensive farnesene isomer mixture (FIM) on Myzus persicae (Sternorrhyncha: Aphidiae) on lettuce ( Lactuca sativa var. Ulmo) in the laboratory and under field conditions. First, we tested under laboratory conditions if FIM has the same effect on M. persicae as it is described for pure EBF. The aphids were influenced by EBF. They stopped feeding, withdrew their stylets, went away from the danger zone, or developed and reproduced more slowly. Therefore, we studied the behavioral response of the aphids after FIM application and aphid reproduction under permanent exposure of FIM. Second, we tested in the field the reaction to FIM either directly applied to lettuce or released by dispensers. In the lab experiments, we found that M. persicae reacts to FIM by walking away and that reproduction tends to be reduced in the presence of FIM. In the field, we found lower numbers of aphids in the treatments with FIM. In particular, dispenser application caused higher aphid reduction compared to spray application on lettuce. In addition, more natural enemies of aphids could be found in dispenser-treated plots. Taken together, these results indicate that the use of FIM could contribute to insecticide-free aphid control in lettuce, but possibly also in other crops.

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