Pollination Ecology of Pedicularis megalantha D. Don (Scrophulariaceae) in the Himachal Himalaya

Abstract

Abstract In the summer of 1990, the pollination ecology of Pedicularis megalantha was studied in the montane‐subalpine spruce‐fir forest zone (2750‐3050 m) on the north slope of Mt. Huttoo at Narkanda, Himachal Pradesh, in the Indian Himalaya. Its yellow, long‐tubed, nectarless flower with a curled rostrum overarched by a broad, inverted lower corolla lip was pollinated exclusively by Bombus albopleuralis and B. tunicatus workers hanging inverted from the corolla and vibrating pollen from introrse anthers concealed within the galea and releasing pollen through a small ventral opening in the galea base. The stigma, protruding from the tip of the rostrum, contacted pollen deposited on the ventral side of the insect's thorax. Corbicular pollen loads from P. megalantha pollinators indicated equal numbers of monolectic and oligolectic foragers. P. megalantha appeared to suffer from competition for pollinators by Cynoglossum wallichii at one site but to be favored in a mixed plant community with nectariferous species offering a forage resource complementary to Pedicularis pollen. As in P. punctata, the long, nectarless corolla tube of P. megalantha appears to function in extending the rostrate vibration pollination mechanism beyond the plant's foliage, which would interfere with its function. It is not an adaptation for nectar‐foraging lepidopteran pollinators. P. megalantha was also found to be a root hemiparasite.