• For the first time, scientists have documented a plant that mimics the smell of injured ants to attract pollinators.
• A dogbane species native to Japan, releases chemical compounds that match the odor ants give off when attacked by spiders.
• Flies that normally feed on injured ants are attracted to the flowers’ scent, and while searching for prey, they inadvertently pollinate the plant without receiving any reward.
• The discovery reveals that floral deception is more diverse than previously thought and suggests many other hidden plant mimicry strategies may still be undiscovered.

See All Key Ideas

In a greenhouse in Tokyo, researcher Ko Mochizuki noticed something unusual. Flies were swarming around the delicate flowers of an obscure plant species. The blooms, however, weren’t offering nectar or bright colors to attract these insects. Instead, they were releasing a chemical signal that smelled like something the flies craved: the scent of an injured ant about to become a meal.

For the first time, scientists have documented a plant that mimics the smell of ants under attack to trick pollinators into visiting its flowers. The plant, Vincetoxicum nakaianum, a flowering dogbane species native to Japan, has evolved an ingenious deception strategy.

“I was working on another research project,” Mochizuki, of the University of Tokyo, said in a statement, “and originally collected this species only as a ‘reference’ for comparison. By chance, I noticed chloropid flies gathering around its flowers in the nursery in the Koishikawa Botanical Gardens, and immediately realized that the flowers might be imitating dead insects.”

The idea came from a lucky combination of events. Mochizuki had taken an intensive training course in 2019 that taught him how to identify the specific fly species visiting the flowers. He had also read research papers on insect-pollinated plants. These experiences came together when he saw the flies gathering on the V. nakaianum flowers.

To test his idea, Mochizuki watched which insects visited the flowers and compared the chemical smell of the flowers with the smell given off by different insects. The analysis showed that the flowers’ odor matched most closely with the smell released by ants when spiders attacked them.

The ant-mimicking dogbane species (Vincetoxicum nakaianum) flowering in its natural habitat. Photo courtesy of Ko Mochizuki .

There was a problem with this theory: no scientific papers had ever reported that chloropid flies or similar species feed on ants that were injured by predators like spiders. To solve this problem, Mochizuki searched social media platforms where amateur naturalists had documented instances of spiders attacking ants while kleptoparasitic flies gathered to feed. These real-world observations supported his theory.

Laboratory testing confirmed the connection. Chemical analysis identified five key compounds in the floral scent: nonane, undecane, octyl acetate, decyl acetate and methyl 6-methyl salicylate. When scientists presented pollinating flies with a mixture of these compounds, the flies were attracted to it. Removing either decyl acetate or methyl 6-methyl salicylate made the mixture unattractive to flies, showing these two compounds were essential for the trick to work.

When scientists compared the compounds released by injured formica ants with the V. nakaianum floral scent, they found them strikingly similar. Behavioral experiments using Y-maze setups confirmed that pollinators were attracted to Formica japonica ants following spider attacks, supporting the mimicry model.

The grass fly visiting the flowers (A) and kleptoparasiting spider hunting ant (B). Photo courtesy of Ko Mochizuki.

“This is the first recorded instance of a plant employing such a sophisticated form of ant mimicry,” Mochizuki said. “That moment, when I saw the flies on the flowers, was truly one of inspiration. A hypothesis suddenly taking shape. This experience taught me that unexpected discoveries often emerge from a combination of preparation and chance.”

The discovery helps scientists understand how plants and pollinators interact and how plants use deception strategies. Ants are one of the most widespread species, and ant mimicry has evolved in many invertebrate species independently.

Plant deception isn’t limited to scent alone. Research estimates that floral deception has evolved in at least 7,500 species of flowering plants, with the majority being orchids. Many of these plants attract pollinators without offering any reward, like nectar.

Plant mimicry occurs when a plant evolves to resemble another organism or object, frequently for defense or to attract pollinators. Most plant mimicry involves visual deception, making this scent-based discovery particularly unusual.

The flies visit the plant because they are searching for injured ants to feed on and lay eggs in. They inadvertently pollinate the plant in the process, helping it reproduce even though they receive nothing in return from the flower.

Mochizuki plans to continue this research by studying how ant mimicry evolved in V. nakaianum and comparing it with related species. He also intends to search for other examples of floral mimicry in other plant groups.

These discoveries could help scientists better understand how plants adapt to their environments and inform conservation efforts as habitats continue to change under human pressures.

Banner image of an ant by Andreas Kay via Flickr CC BY-NC-SA 2.0.

Consider the scorpions

Citations:

Mochizuki, K. (2025). Olfactory floral mimicry of injured ants mediates the attraction of kleptoparasitic fly pollinators. Current Biology, 35(20), 5097-5105. doi:10.1016/j.cub.2025.08.060 

Jin, X., Ren, Z., Xu, S., Wang, H., Li, D., & Li, Z. (2014). The evolution of floral deception in Epipactis veratrifolia (Orchidaceae): From indirect defense to pollination. BMC Plant Biology, 14(1), 63. doi:10.1186/1471-2229-14-63

Liz Kimbrough is a staff writer for Mongabay and holds a Ph.D. in ecology and evolutionary biology from Tulane University, where she studied the microbiomes of trees. View more of her reporting here.

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