Plant phenotypic plasticity changes pollinator-mediated selection

Abstract

Many organisms change their phenotype in response to the environment, a phenomenon called phenotypic plasticity. Yet we hardly understand how such plasticity can affect biotic interactions and the resulting phenotypic selection. Here we use fast cycling Brassica rapa plants in a proof-of-concept experiment in the greenhouse to study the link between plasticity and selection. We detected strong plasticity in morphology, nectar, and floral scent in response to different soil types and aphid herbivory. We found positive selection on nectar and several morphological traits. Bumblebee-mediated selection on a principle component representing plant height, flower number, and flowering time (mPC3) differed depending on soil type and herbivory. For plants growing in richer soil, selection was stronger in the absence of herbivores, whereas for plants growing in poorer soil selection was stronger with herbivory. We showed that bumblebees visited tall plants with many flowers over-proportionally when they were rare (i.e. in plants in poor soil with herbivory), thus causing stronger positive selection on this trait-combination. We suggest that with strong plasticity under most stressful conditions, a shift in pollinator behavior may speed up adaptation to local environmental factors.

Biotic interactions promote local adaptation to soil in plants

“…Bumblebee first choices was taken as a measure of attractiveness of plants to these highly efficient pollinators 59 . Bumblebee visitations of generation one and two showed that the number of visits is highly correlated with seed set in this obligatorily outcrossing, animal pollinated plant (r784=0.70 p<0.001 68 ), and thus is a good fitness proxy. Because "relative seed set" had a zero-inflated distribution (ca.…”

Insect trash is a plant’s treasure: effects of insect exuviae as soil amendment on pollinator performance and plant reproduction

“…First, low levels of nutrients in the soil can negatively affect seed production (Malhi and Gill, 2006). Under nutrient limitation, seed yield can be reduced, because not all fertilised ovules develop into seeds (Dorey and Schiestl, 2022). Second, alterations in the soil environment in-Effects of insect exuviae as soil amendment on pollinator performance and plant reproduction fluence plant traits that are used as signal by the plants to attract pollinators, thus affecting pollination success (Strauss and Whittall, 2006;Carvalheiro et al, 2021).…”