Hornets found to be primary pollinators of two Angelica species

by University of Tokyo
April 30, 2024

Researcher Ko Mochizuki of the University of Tokyo discovered that two species in the genus Angelica are pollinated primarily by hornets. This overturns the conventional belief that Angelica species are “generalists,” meaning that there is not one primary pollinator but a variety of species. As hornets are rarely primary pollinators, the discovery also impacts future ecological research and conservation efforts. The findings were published in the journal Ecology.

White, small, open, secretes nectar and produces pollen: these are the kinds of flowers that many types of insects can reach and are attracted to. Most of the plants in the carrot family, Apiaceae, fit this description perfectly. As such, the species in this family are considered to be generalists. In extreme cases, over 100 different insect species visit their flowers. Not so with Angelica decursiva and Angelica hakonensis, two species in the genus Angelica in the family.

“I observed a fierce visitation by hornets for the first time in 2015 in Nagano Prefecture,” Mochizuki recalls, “and then again in 2018 in the Nikko Botanical Garden where they were feeding on the nectar of the inflorescences of A. decursiva and A. hakonensis. Since it was a dogma that species in the family Apiaceae are generalists, this observation motivated me to investigate if the two Angelica species were pollinated predominantly by hornets.”

Keep reading: https://www.s.u-tokyo.ac.jp/en/press/10318/

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecy.4311