Pollinator-Mediated Selection on Floral Traits of Primula tibetica Differs Between Sites With Different Soil Water Contents and Among Different Levels of Nutrient Availability

Yun Wu,Xuyu Duan,Zhaoli Tong,Qingjun Li

doi:10.3389/fpls.2022.807689

Abstract

Abiotic environmental factors are predicted to affect plant traits and the intensity of plant-pollinator interactions. However, knowledge of their potential effects on pollinator-mediated selection on floral traits is still limited. We separately estimated the effects of soil water (two sites with different soil water contents) and N-P-K nutrient availability (different levels of nutrient addition) on pollinator-mediated selection on floral traits of Primula tibetica (an insect-pollinated perennial herbaceous species). Our results demonstrated that floral traits, plant reproductive success and pollinator-mediated selection on floral traits varied between sites with different soil water contents and among different levels of nutrient addition. The strength of pollinator-mediated selection was stronger at the site with low soil water content than at the site with high soil water content, and first decreased and then increased with increasing N-P-K nutrient addition. Our results support the hypothesis that abiotic environmental factors influence the importance of pollinators in shaping floral evolution.

Highlights

One goal of evolutionary ecologists is to understand and predict floral evolutionary responses in complex biotic and abiotic environments (Smith, 2010; Dalrymple et al, 2020)
We examined (1) whether pollinator-mediated selection on floral traits differed between sites with different soil water contents and (2) whether the strength of pollinator-mediated selection decreased with increasing N-P-K nutrient availability
Pollinator-mediated stabilizing selection on flowering start date occurred in the 0.5% N-P-K nutrient addition treatment (Supplementary Table 13 and Figure 5B)

Summary

INTRODUCTION

One goal of evolutionary ecologists is to understand and predict floral evolutionary responses in complex biotic and abiotic environments (Smith, 2010; Dalrymple et al, 2020). Global climate change leads to regional soil water limitations (Burkle and Runyon, 2016), and excessive use of chemical fertilizers in agricultural production is widespread around the world (Yang, 2006; Liu et al, 2015) Under these scenarios, it is necessary to clarify the effect of soil water and nutrient availability ( nutrient addition) on the pollination environment, plant-pollinator interactions and pollinator-mediated selection. Flowering phenology (i.e., flowering duration per plant) and floral display size (i.e., plant height, number of flowers and corolla size) varied among sites with different soil water content and nutrient availability (Supplementary Figures 1, 2) These variations in floral traits may influence pollinator visitations, the intensity of plant-pollinator interactions and the importance of pollinators in shaping floral evolution. We examined (1) whether pollinator-mediated selection on floral traits differed between sites with different soil water contents and (2) whether the strength of pollinator-mediated selection decreased with increasing N-P-K nutrient availability

MATERIALS AND METHODS

DISCUSSION

Findings

DATA AVAILABILITY STATEMENT