A rare Japanese flower tricks flies into pollinating it by mimicking the smell of wounded ants, marking the first known case of a plant using ants as a mimicry model.
The plant, Vincetoxicum nakaianum, releases volatiles that copy the alarm signals from injured Formica ants, drawing in kleptoparasitic flies that scavenge on hurt insects. Researchers uncovered this clever deception through field observations, chemical analyses, and behavioral tests, revealing how the flower exploits the flies’ feeding habits for reproduction. The study, led by Ko Mochizuki of the University of Tokyo and published in Current Biology, opens new insights into fly pollination and plant evolution.
Found in cool-temperate forests of central and northern Honshu, V. nakaianum blooms in spring with small inflorescences that attract mostly male chloropid flies like Polyodaspis ruficornis and Conioscinella divitis. These flies, which feed on the fluids of injured bugs, carry the plant’s pollinaria on their proboscis while probing for nectar-like secretions.
Chemical sleuthing showed the flower’s scent includes nonane, undecane, octyl acetate, decyl acetate, and methyl-6-methyl salicylate—compounds matching those from crushed or spider-attacked Formica japonica and Formica hayashi ants. Field traps baited with a synthetic mix lured the flies, but omitting decyl acetate or methyl-6-methyl salicylate killed the appeal. Y-maze tests confirmed flies preferred spider-killed ants over controls.
“These results indicate that V. nakaianum employs the olfactory mimicry of injured ants to attract pollinators,” Mochizuki writes. “This study highlights the diverse evolutionary outcomes of adaptation to fly pollinators and the evolutionary capacity of ant mimicry in plants.”
Citations: Current Biology. DOI: 10.1016/j.cub.2025.08.060
