The Relationship of Visiting Insect Diversity and Density of Valeriana jatamansi with Increasing Altitude in Western Himalaya

Abstract

In light of the recent evidences that pollinators have a significant implication for maintenance of pollen-mediated gene flow, the present study has been undertaken to investigate flowering phenology and visiting insect diversity and density in 9 different populations of Valeriana jatamansi. The performance of the V. jatamansi breeding system was also investigated at an experimental site. Field experiments were performed on control and visiting insect excluded plants (a total of 90 plants). Across populations, a total of 76 visiting insects belonging to 20 species were recorded. Comparison of visiting insects excluded plants and natural plants revealed 63.49% seed setting produced by natural-pollination, whereas only 37.51% of seeds were produced by self-pollination. Significantly higher seed viability (t = 4.284; p < 0.02) was recorded in seeds from control plants as compared to visiting insect excluded plants. Similarly, higher seed germination (38%) and seed weight were recorded in control plants as compared to visiting insect excluded plants. The total insect number (r = − 0.707) and species diversity (− 0.897) exhibited significantly (p < 0.05) negative relationship with altitude. A significant negative correlation existed between plant density and altitude (r = − 0.772; p < 0.05). The study provides further evidence that pollinators (and their diversity) are critical for sustaining genetic diversity and consequent adaptive capability in V. jatamansi.