Just showy or simply honest? Signalling of the floral reward in yellow iris (Iris pseudacorus L.)

Published: 6 December 2022| Version 1 | DOI: 10.17632/6c43x2856f.1
Marcin Mazurkiewicz


Abstract Pollinators often cannot directly assess the quality and quantity of rewards offered by flowers. As a result, the interaction between plants and pollinators is mediated by the expression of signals that advertise the rewards. As pollinators are looking for rewards, they should prefer honest signals, which indicate reward properties. To gain more insight into the factors shaping plant-pollinator interactions, we tested the relationship between the visual features of exceptionally large Iris pseudacorus and the quantity and quality of the food reward offered. We assessed the frequency of pollinator visits to the measured flowers and their reproductive success. Additionally, we experimentally changed the visual features of flowers, which may play a role in plant-pollinator communication (tepals shortening or covering the spot on the tepals) and assessed the frequency of pollinator visits and reproductive success in such modified flowers. Our results indicate that flower traits are predictors of reward properties. For example, the spot on the tepal is an indicator of the nectar volume. We found correlations between flower size and the sugar or amino acid amount. The size of the flower traits did not influence the frequency of pollinator visits, but removing the spot on the tepal resulted in a lower frequency of visits. Flowers were mostly visited by Apis mellifera, which was responsible for more than 80% of the recorded visits. Thus, by analysing the collected data, we can infer that some flower features may be an honest signal for pollinators; however, A. mellifera does not use it while foraging. Data description Data was collected in June and September 2021. The aim of the study was to investigate the occurrence of the "Honest signaling" phenomenon in the case of Iris psuedacorus. The research carried out consisted of measuring the flowers and recording pollinator activity in these flowers, as well as collecting nectar for chemical analysis. Seeds were also collected from the measured plants to test their reproductive success. In addition, in some of the studied plants, the authors modified the morphology of flowers. The data includes: -measurements of individual parts of Iris pseudacorus flowers collected in the field -data on the frequency of visits to flowers by their pollinators collected in the field -nectar chemical analysis data -data on the number of seeds collected



Uniwersytet Warszawski Wydzial Biologii


Ecology, Plant Ecology, Pollination


Uniwersytet Warszawski