The PERCEPSION project has started in January 2020, only a few weeks before the onset on the Covid crisis. Given the highly experimental nature of the PERCEPSION project, its objectives had to be considerably re-orientated during the first year of the project. The experimental evolution protocol, which was supposed to last for two years and which had started before the first lock-down in France, was stopped for over six month. This experiment is therefore still ongoing. The beneficiary has therefore devoted most of the first year of the grant to the writing of a review/opinion paper that has promoted the main ideas of the WP1, and which has been published in one of the most renowned journals of the field (Trends in Ecology and Evolution). As described in details below, all experimental parts foreseen in the PERCEPSION project have started and yield important progresses but are still ongoing given the strong delays incurred by the Covid crisis.
WP1: Experimental evolution of the flower morphology and style physiology as a mechanism to filter mating partners
WP1 involved growing for 10 generations of the plant model Brassica rapa fast plants (characterized by a very short generation time) with five experimental populations subjected to hand-pollination in polygamy and five others in monogamy (which eliminates any form of sexual selection). After the independent evolution of these populations in monogamy versus polygamy, the goal is to test for the evolution of pollen competitive traits in polygamy compared to monogamy, but also for the evolution of a putative female cryptic choice i.e. the evolution of pistil traits that bias paternity for the pollen traits.
The first eigth generations of experimental evolution have been carried out during the course of the PERCEPSION project. To do so, the beneficiary has designed a protocol for hand-pollinating Brassica rapa fast plants and for growing them. The beneficiary has also developed a multiplex for amplifying microsatellite markers to perform paternity analyses. At generation 3, we have sampled leaves of maternal and paternal plants, along with their offspring for DNA extraction and PCR amplification. A paternity analysis using this material is ongoing to validate our monogamy versus polygamy treatment. The evolution of pollen and pistil traits will soon be evaluated and several publications are foreseen following WP1. The PERCEPSION project will be associated to these publications.
WP2: Communication between plants, evaluating the possibility of a perception of the availability and diversity of mating partners
WP2 involved testing whether plants can potentially perceive the intensity of sexual selection through sex ratios or pollinator sounds, and respond to it by plastically changing their traits involved in the dispersal of pollen to mates.
The beneficiary has carried out an experiment to provide a test of plants ability to perceive the sound of pollinators and its abundance, and to respond to it by altering their scent production. A protocol has been designed to measure scent components for B. rapa thanks to a proton-transfer-reaction mass spectrometer, which provides real-time data about the production of volatile compounds of a given mass. We have performed an experiment in a limited number of B. rapa plants, which showed that the scent production of plants exposed to the sound of bumblebees produced by a loudspeaker differed from that of plants exposed to silence. We are currently re-iterating this experiment with a larger number of plants. These results extend recent findings in another plant species showing that exposition to pollinator sounds elicited a rapid increase in the sugar concentration in nectar.
All of resulting publications and all seminars and scientific talks given during the course of the project (and future ones that will be given on the outcome of the experiments) acknowledge funding from the EU and mention the Horizon 2020 Framework program and the grant number.
