@article{VenjakobLeonhardtKlein2020,
  author    = {Venjakob, Christine and Leonhardt, Sara and Klein, Alexandra-Maria},
  title     = {Inter-individual nectar chemistry changes of field scabious, Knautia arvensis},
  series = {Insects},
  volume    = {11},
  journal   = {Insects},
  number    = {2},
  issn      = {2075-4450},
  doi       = {10.3390/insects11020075},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200866},
  year      = {2020},
  abstract  = {Nectar is crucial to maintain plant-pollinator mutualism. Nectar quality (nutritional composition) can vary strongly between individuals of the same plant species. The factors driving such inter-individual variation have however not been investigated closer. We investigated nectar quality of field scabious, Knautia arvensis in different grassland plant communities varying in species composition and richness to assess whether nectar quality can be affected by the surrounding plant community. We analyzed (with high performance liquid chromatography) the content of carbohydrates, overall amino acids, and essential amino acids. Amino acid and carbohydrate concentrations and proportions varied among plant individuals and with the surrounding plant community but were not related to the surrounding plant species richness. Total and individual carbohydrate concentrations were lowest, while proportions of the essential amino acids, valine, isoleucine, leucine (all phagostimulatory), and lysine were highest in plant species communities of the highest diversity. Our results show that K. arvensis nectar chemistry varies with the composition of the surrounding plant community, which may alter the taste and nutritional value and thus affect the plant's visitor spectrum and visitation rate. However, the strong inter-individual variation in nectar quality requires additional studies (e.g., in semi-field studies) to disentangle different biotic and abiotic factors contributing to inter-individual nectar chemistry in a plant-community context.},
  language  = {en}
}
@article{VenjakobRuedenauerKleinetal.2022,
  author    = {Venjakob, C. and Ruedenauer, F. A. and Klein, A.-M. and Leonhardt, S. D.},
  title     = {Variation in nectar quality across 34 grassland plant species},
  series = {Plant Biology},
  volume    = {24},
  journal   = {Plant Biology},
  number    = {1},
  doi       = {10.1111/plb.13343},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-262612},
  pages     = {134 -- 144},
  year      = {2022},
  abstract  = {Floral nectar is considered the most important floral reward for attracting pollinators. It contains large amounts of carbohydrates besides variable concentrations of amino acids and thus represents an important food source for many pollinators. Its nutrient content and composition can, however, strongly vary within and between plant species. The factors driving this variation in nectar quality are still largely unclear. We investigated factors underlying interspecific variation in macronutrient composition of floral nectar in 34 different grassland plant species. Specifically, we tested for correlations between the phylogenetic relatedness and morphology of plants and the carbohydrate (C) and total amino acid (AA) composition and C:AA ratios of nectar. We found that compositions of carbohydrates and (essential) amino acids as well as C:AA ratios in nectar varied significantly within and between plant species. They showed no clear phylogenetic signal. Moreover, variation in carbohydrate composition was related to family-specific structural characteristics and combinations of morphological traits. Plants with nectar-exposing flowers, bowl- or parabolic-shaped flowers, as often found in the Apiaceae and Asteraceae, had nectar with higher proportions of hexoses, indicating a selective pressure to decelerate evaporation by increasing nectar osmolality. Our study suggests that variation in nectar nutrient composition is, among others, affected by family-specific combinations of morphological traits. However, even within species, variation in nectar quality is high. As nectar quality can strongly affect visitation patterns of pollinators and thus pollination success, this intra- and interspecific variation requires more studies to fully elucidate the underlying causes and the consequences for pollinator behaviour.},
  language  = {en}
}