A Pollination Ecology Study of Pedicularis Linnaeus (Orobanchaceae) in a Subalpine to Alpine Area of Northwest Sichuan, China

Abstract

Pollination ecology and habitat preference of Pedicularis species were studied in a transitional zone between subalpine coniferous forests and alpine meadows in northwestern Sichuan of China. Pedicularis species exhibited apparent preferences for different microhabitats. Species with long rostrate and contorted galea were nectarless and their mean corolla tube length ranged from 7 to 50 mm while species without long rostrate and contorted galea produced nectar and their corolla tube length averaged from 8 to 18 mm. Bumblebees were the sole pollinators of the studied species and five bee species pollinated seven Pedicularis species with one species pollinating all the Pedicularis species. Pollinators that visited nectariferous species had longer tongues than those that visited nectarless species and they spent longer time on nectariferous than on nectarless species. All Pedicularis species except for P. rex subsp. lipskyana were pollinated by worker bees. Pedicularis rex subsp. lipskyana was pollinated nototribically by worker, male and queen bumblebees through stigmatic contact with residual pollen on the left side of the bee’s head. Morphology of pollinators, rather than pollinator species, may play the key role in diversification of Pedicularis. Microhabitats rather than pollination may be the separation barrier in propagation. Factors contributing to high diversity of Pedicularis need further study.