Increased Insect Pollinator Service Overcomes Barriers in Reproductive Success of Aesculus indica Colebr. (Hippocastanaceae) in the Temperate Himalaya.

Aesculus indica Colebr. is a monecious, deciduous woody tree species of the temperate regions of the Himalaya. It is cultivated for its commercial use in agro-forestry practices. The present research on pollination biology and conservation of Aesculus indica growing in Kumaon Himalaya was carried out in the temperate forest ecosystem of Lohaghat, Uttarakhand, India. The field experiments were conducted on five randomly selected populations of the study plant during April 2017 to September 2017 to quantify the diversity and foraging behavior of insect visitors and their influence on fruiting success of the plant. Of the total 18 species of insects recorded as floral visitors, 77.78% of the total species belonged to the order Lepidoptera while the rest belonged to the order Hymenoptera. Butterflies foraged the flowers maximum during 10.00–13.00 h, whereas bees were more active during morning times (07.00–10.00 h). The flower handling time and foraging rate as the parameters of foraging behavior varied among insect floral visitors. Butterflies were recorded as the most frequent floral visitors accounting 62.22% of the total floral visits. Experimentally, it was found that Aesculus indica is an ambophilous plant i.e., relying on both wind and insects for its reproductive success, and exhibits psychophilous and melitophilous syndromes for pollination. The overall results on pollination mechanism of the plant would be useful in developing conservation measures for environmental stability in the face of global climate change. [ABSTRACT FROM AUTHOR]