Allometric allocation strategy of entomophilous species under pollinator loss in a temperate steppe

Abstract The ongoing climate change has been a threat to insect survival, which could have negative consequences for growth and development of plant species through plant‐insect interactions. However, how pollinator loss affects the vegetative and reproductive growth of entomophilous plant species remains largely unknown. In this study, encryption gauzes were used to exclude pollinators to explore the effects of pollinator loss on phenology and aboveground biomass allocation (reproductive and vegetative biomass) of three perennial entomophilous plant species in a temperate steppe on the Mongolian Plateau. The results showed that pollinator exclusion did not affect the beginning, whereas it delayed the ending of flowering date, and thus prolonged the flowering duration across the three monitored species. In addition, pollinator exclusion decreased fruit set and reproductive allocation without changing flower number. By contrast, stimulated plant height of monitored species was observed in pollinator exclusion plots, which could be a strategy for increasing attractiveness under pollinator exclusion. Moreover, the relationships between reproductive and vegetative biomass changed with plant size and were altered by pollinator exclusion, suggesting that aboveground biomass allocation strategy conforms to the allometric allocation theory under reduced plant‐pollinator interactions. The findings of enhanced vegetative growth induced by pollinator loss suggest benefits for aboveground biomass accumulation and greater regeneration via vegetative propagation in perennial entomophilous species under decreasing pollinator numbers driven by climate change in temperate grasslands.