Insect exuviae as soil amendment affect flower reflectance and increase flower production and plant volatile emission

• Published in: Plant, cell and environment Vol. 46; no. 3; pp. 931 - 945
• Main Authors: Barragán‐Fonseca, Katherine Y., Rusman, Quint, Mertens, Daan, Weldegergis, Berhane T., Peller, Joseph, Polder, Gerrit, Loon, Joop J. A., Dicke, Marcel
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.03.2023; John Wiley and Sons Inc
• Subjects: Animals; Brassica; Brassica nigra; Breeding success; Chemical composition; Composition; Emission analysis; Emissions control; Environmental factors; floral traits; Flowers; Flowers - anatomy & histology; Gas chromatography; Herbivory; insect residual streams; Insecta; Insects; Machine learning; Mass spectrometry; Mass spectroscopy; Organic compounds; Organic soils; Original; plant phenotype; Plants (botany); plant–pollinator interactions; Pollination; Pollinators; Reflectance; Reproduction; Soil; Soil amendment; Soils; VOCs; Volatile organic compounds; Volatile Organic Compounds - analysis; herbivory; plant phenotype; plant-pollinator interactions; insect residual streams; Brassica nigra; floral traits
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.14516

Soil composition and herbivory are two environmental factors that can affect plant traits including flower traits, thus potentially affecting plant–pollinator interactions. Importantly, soil composition and herbivory may interact in these effects, with consequences for plant fitness. We assessed the main effects of aboveground insect herbivory and soil amendment with exuviae of three different insect species on visual and olfactory traits of Brassica nigra plants, including interactive effects. We combined various methodological approaches including gas chromatography/mass spectrometry, spectroscopy and machine learning to evaluate changes in flower morphology, colour and the emission of volatile organic compounds (VOCs). Soil amended with insect exuviae increased the total number of flowers per plant and VOC emission, whereas herbivory reduced petal area and VOC emission. Soil amendment and herbivory interacted in their effect on the floral reflectance spectrum of the base part of petals and the emission of 10 VOCs. These findings demonstrate the effects of insect exuviae as soil amendment on plant traits involved in reproduction, with a potential for enhanced reproductive success by increasing the strength of signals attracting pollinators and by mitigating the negative effects of herbivory. Summary statement Insect exuviae as soil amendment affected plant traits involved in reproduction of Brassica nigra plants, with a potential for enhanced reproductive success by enhancing pollinator attraction and by mitigating the negative effects of herbivory.