Rosa Rubicondior: Refuting Creationism - The Lengths Plants Will Go To Just To Get Pollinated

Friday, 26 September 2025

Refuting Creationism - The Lengths Plants Will Go To Just To Get Pollinated - No Intelligence Needed

The grass fly visiting the flowers (A) and kleptoparasiting spider hunting ant (B)

Press Releases - SCHOOL OF SCIENCE THE UNIVERSITY OF TOKYO

The driving force behind evolution is reproductive success, so in a broad sense every adaptation can be seen as a reproductive strategy. Few, however, are as peculiar as that of Vincetoxicum nakaianum, a dogbane species native to Japan. Rather than relying on nectar rewards or visual lures to attract pollinators, this plant enlists the services of kleptoparasitic chloropid flies — insects that usually home in on the scent of injured prey in order to steal a meal.

In a remarkable twist, the flowers of V. nakaianum release chemical signals that closely mimic the odour of ants under attack by predators, especially spiders. Drawn in by what they perceive as the scent of a potential victim to exploit, the flies inadvertently collect and deposit pollen as they move from flower to flower. This unusual strategy has now been documented in detail in a study led by Ko Mochizuki of the University of Tokyo, published in Current Biology, and described in a University of Tokyo School of Science press release.

What makes this particularly striking is how roundabout and intricate the mechanism is. If an intelligent designer had set out to ensure pollination, far simpler methods are available — from bright colours and nectar rewards to direct reliance on wind. Instead, V. nakaianum has evolved a convoluted route, exploiting the specialised behaviour of flies that themselves depend on the predation of ants by spiders. Such elaborate, contingent solutions are precisely what we expect from evolution by natural selection acting over countless generations, not from foresightful design.

Background^ Kleptoparasitic Chloropid Flies Family: Chloropidae (commonly called grass flies or frit flies)

Diversity: Over 2,000 described species worldwide, with varied diets and habits. Most are small, inconspicuous flies often associated with grasses.

Kleptoparasitic lifestyle:

A minority of chloropid species have evolved kleptoparasitism — a feeding strategy where they exploit the prey of other predators.
These flies are attracted to the odours of injured or dying insects, homing in to feed on body fluids.
They often exploit insects subdued by predators such as spiders or wasps, effectively stealing food without expending energy on hunting.

Pollination link:

While most kleptoparasitic flies are not regular pollinators, their strong attraction to specific distress odours makes them susceptible to floral deception.
Vincetoxicum nakaianum is the first documented case where a plant mimics the scent of ants under attack to recruit kleptoparasitic chloropids for pollination.
The study identified four species of chloropid flies involved in this interaction.

Evolutionary significance:

This represents a novel example of olfactory mimicry in pollination biology.
It highlights how plants can evolve to manipulate highly specialised behaviours in insects, even those that are not typical flower visitors.
The system is fragile and highly contingent, depending not only on the plant and the fly but also on the ecological presence of ants and their predators.

First-ever documented case of a plant mimicking ants to attract pollinators
A dogbane species is found to mimic the smell of injured ants to attract flies that feed on the ants and pollinate the flowers
Ko Mochizuki of the University of Tokyo has discovered that Vincetoxicum nakaianum, a dogbane species native to Japan described for the first time by Mochizuki and his collaborators only a year ago, mimics the smell of ants attacked by spiders to attract flies that feed on such attacked insects, and in the process pollinate the flowers. This is the first case of a plant mimicking the odor of ants, revealing that the scope of floral mimicry is more diverse than previously imagined. The findings are published in the journal Current Biology.

The grass fly visiting the flowers (A) and kleptoparasiting spider hunting ant (B)

The smell of warm, freshly baked bread has surely attracted many a customer to enter the shop as they pass by. Grass flies are no different: they are also attracted to the smell of their daily bread, injured ants. As they move from flower to flower in search of already injured prey, they also do flowers a great service: they pollinate them. Because ants are one of the most widespread species, and ant mimicry has independently evolved in many invertebrate species, it stands to reason that plants could have also evolved to mimic ants in one way or another. However, such cases had never been reported.

I was working on another research project 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.

Ko Mochizuki, author.
Botanical Gardens
Graduate School of Science
The University of Tokyo
Tokyo, Japan.

This recognition was thanks to a string of thus far unrelated experiences. His participation in an intensive training course in 2019 helped him recognize the fly species swarming the flower. He also happened to be familiar with some previous studies that described plants pollinated by chloropid flies emitting odors resembling those of insects.

Following his hunch, Mochizuki set out to methodically observe the visitors on these flowers and compare the odors released by the flowers to odors released by various kinds of insects. He found that the smell of ants being attacked by spiders was the closest match. However, his hypothesis of ant mimicry was standing on frail legs: there had not been any official publications of chloropid flies, or any other similar fly species, targeting ants hunted and injured by other animals, such as spiders. So, Mochizuki turned to social media for more unconventional evidence. There, he found many amateur naturalists documenting what he had suspected: ants attacked by spiders, which then attracted kleptoparasitic (organisms that steal food from another) flies. This gave him confidence to test the hypothesis behaviorally and confirm whether chloropid flies were indeed more attracted to the smell of ants attacked by spiders than to other smells.

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.

Ko Mochizuki.

Talking of preparation… Mochizuki is already preparing for the next project.

I would like to investigate the evolutionary background of ant mimicry by comparing the pollination systems, evolutionary history, and genetic makeup of Vincetoxicum nakaianum and its close relatives. In addition, since this study suggests that many forms of floral mimicry may remain hidden, I plan to explore other species, both within Vincetoxicum and in unrelated plant groups, to uncover further examples of potential mimicry.

Ko Mochizuki.

Vincetoxicum nakaianum flowering in the natural habitat

Publication:
Mochizuki, Ko
Olfactory floral mimicry of injured ants mediates the attraction of kleptoparasitic fly pollinators Current Biology (2025) doi: 10.1016/j.cub.2025.08.060

© 2025 Elsevier.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

Highlights

Vincetoxicum nakaianum is pollinated by kleptoparasitic chloropid flies
Floral scent resembles volatiles released from Formica ants attacked by spiders
Two ant volatiles emitted by flowers are essential for pollinator attraction
First evidence of ants as models for floral mimicry

Summary
Specialized pollination by flies often involves specific floral mimicry of various food and brood substrates.^1,2,3 However, identifying a precise model is challenging due to the ecological diversity of flies, which subject plants to diverse selection pressures.^4,5 Here, I report that Vincetoxicum nakaianum (Apocynaceae) lures kleptoparasitic fly pollinators by producing a floral scent mimicking the volatiles released by injured ants. Field observations confirmed that V. nakaianum is pollinated by four kleptoparasitic chloropid fly species that feed on the body fluids of injured insects.^6,7,8,9,10 In chemical analysis of floral scent, nonane, undecane, octyl acetate (8Ac), decyl acetate (10Ac), and methyl-6-methyl salicylate (6-MMS)^11,12,13 were identified consistently across all samples. A synthetic mixture of these five floral scent components was attractive to pollinating flies. However, in the absence of 10Ac or 6-MMS, the mixture was unattractive to flies. When 10Ac and 6-MMS were offered in combination, flies were attracted; these two compounds alone were, however, not attractive. The compositions of volatiles emitted from injured Formica ants closely resembled V. nakaianum floral scent, sharing 10Ac and 6-MMS. Y-maze experiments confirmed that pollinators were attracted to Formica japonica following spider attack. These results indicate that V. nakaianum employs the olfactory mimicry of injured ants to attract pollinators. Although ants are pervasive and frequently interact with plants, no flowers have been reported to mimic ants. This study highlights the diverse evolutionary outcomes of adaptation to fly pollinators and the evolutionary capacity of ant mimicry in plants.
Graphical abstract

What this discovery so neatly illustrates is the opportunistic and circuitous nature of evolution. There is no foresight, no blueprint, no grand designer mapping out the simplest route to a goal. Instead, chance variations are tested against environmental pressures, and those that confer even a slight reproductive advantage persist. Over time, these accumulate into astonishingly intricate systems such as this floral deception.

It is worth asking why an all-powerful “intelligent designer” would choose such a convoluted strategy when much simpler and more efficient pollination systems exist. Bright petals and nectar rewards, for example, are widespread and highly effective, yet Vincetoxicum nakaianum has evolved an elaborate scheme involving the mimicry of injured ants, the behavioural quirks of kleptoparasitic flies, and the predation of ants by spiders. This is not the economy of design one would expect from intelligence — it is the messy, roundabout ingenuity that only natural selection can produce.

Creationist claims that such complexity must point to supernatural design fall flat when examined in detail. What we actually see is evolution working with whatever material is at hand, producing contingent solutions that are effective but rarely elegant. Far from being evidence of design, the baroque pollination strategy of V. nakaianum is yet another testament to the power of blind evolutionary processes to exploit even the most unlikely ecological niches.

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