How to trick a hornet

Behind the Cover: New Phytologist 220:3, November 2018

Plants use a variety of ingenious mechanisms to arrange for the onward transport of their seeds by unsuspecting creatures. Stemona tuberosa might employ one of the strangest seed dispersal methods of all.

The photograph on the cover of New Phytologist 220:3 shows a hornet (Vespa velutina) biting off a diaspore (seed plus elaiosome, a fleshy body attached to the seed) from S. tuberosa. Gao Chen, a researcher at the Kunming Institute of Botany, Chinese Academy of Sciences, China, captured the image while researching S. tuberosa‘s peculiar method for sending its seeds further afield.

Plant tricks predatory hornet Vespa velutina into dispersing its seeds by smelling like prey. Courtesy of Gao Chen.

S. tuberosa uses vespicochory – the plant convinces hornets to grab its seeds and fly away with them. The hornets eventually drop the seeds, dispersing them in the process. Gao and his colleagues wanted to find out why the hornets were so eager to attack the seeds and carry them off; what visual, olfactory (smell) or gustatory (taste) cues did the hornets find so alluring?

In their paper recently published in New Phytologist, Gao and his colleagues reveal that S. tuberosa tricks hornets into making off with its seeds by making them smell like prey. The seeds release a cocktail of particular hydrocarbon compounds, which stimulate the hornets’ antennae, attracting the insects with the suggestion of a meal for their young.

One hornet may disperse all the seeds in a population‘ – Gao Chen

The researchers found that the hornets didn’t just visit the plant once, but returned many times. “One individual visited more than 120 times to carry the diaspores,” said Gao. “Therefore, we guess one hornet may disperse all the seeds in a given population.” The research gives us a fantastic example of a mutualism between insects and plants.

The paper in which Gao and colleagues describe their work is published in a Feature issue of New Phytologist: New insights into plant volatiles.

Read the paper: Chen, G., Wang, Z., Wen, P., Wei, W., Chen, Y., Ai, H. and Sun, W. (2018) Hydrocarbons mediate seed dispersal: a new mechanism of vespicochoryNew Phytologist 220: 714-725. doi: 10.1111/nph.15166

Read a longer piece about this research in Discover Magazine.

Dr Mike Whitfield (@mgwhitfield)
Development Coordinator
New Phytologist Trust