Egan, Paul
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences
Abstract
Plant compounds associated with herbivore defence occur widely in floral nectar and can impact pollinator health. We showed previously that Rhododendron ponticum nectar contains grayanotoxin I (GTX I) at concentrations that are lethal or sublethal to honeybees and a solitary bee in the plant's non-native range in Ireland. Here we further examined this conflict and tested the hypotheses that nectar GTX I is subject to negative pollinator-mediated selection in the non-native range, but that phenotypic linkage between GTX I levels in nectar and leaves acts as a constraint on independent evolution. We found that nectar GTX I experienced negative directional selection in the non-native range, in contrast to the native Iberian range, and that the magnitude and frequency of pollinator limitation indicated that selection was pollinator-mediated. Surprisingly, nectar GTX I levels were decoupled from those of leaves in the non-native range, which may have assisted post-invasion evolution of nectar without compromising the anti-herbivore function of GTX I (here demonstrated in bioassays with an ecologically relevant herbivore). Our study emphasizes the centrality of pollinator health as a concept linked to the invasion process, and how post-invasion evolution can be targeted toward minimizing lethal or sub-lethal effects on pollinators.This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
Keywords
phenotypic selection; post-invasion evolution; toxic nectar; plant-herbivore-pollinator interactions
Published in
Philosophical Transactions B: Biological Sciences
2022, volume: 377, number: 1853, article number: 20210168
SLU Authors
Associated SLU-program
Biodiversity
SLU Plant Protection Network
Global goals (SDG)
UKÄ Subject classification
Ecology
Evolutionary Biology
Publication identifier
- DOI: https://doi.org/10.1098/rstb.2021.0168
Permanent link to this page (URI)
https://res.slu.se/id/publ/120089