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Scientists have found a clever way a Japanese plant survives and reproduces. The plant is called Vincetoxicum naikanum, or Japanese dogbane. It has developed a unique method to recruit visitors to help spread its pollen. The flower releases a specific scent that mimics the signal of an injured ant. This strange odor tricks a specialized type of fly, which normally feeds on dead or dying insects. By pretending to be a wounded ant, the plant draws the flies to its bloom.
When the flies land on the flower in search of food, they become covered in pollen. As they fly away, they carry this pollen to other flowers, facilitating the plant's growth of new seeds. The flies receive no food in return, but the plant succeeds.
Ko Mochizuki, a botanist at the University of Tokyo, discovered this phenomenon. He shared his detailed results in the journal Current Biology on October 20. His work illustrates the complex relationships between plants and animals, demonstrating how one species can deceive another for survival. This study serves as a prime example of biological mimicry, revealing how nature uses deception to solve problems.
The story began with a simple yet curious observation. Mochizuki was working at the Koishikawa Botanical Gardens in Tokyo when he noticed large clouds of small flies hovering over the dogbane flowers. These flies are known as grass flies or milichiid flies. To the human eye, the flowers appear quite plain. This behavior was unusual because grass flies are not typical pollinators; they do not seek sweet nectar like bees. Instead, they are scavengers that consume fluids from dead or injured insects. They are not drawn to flowers for sweet treats but follow the scent of actual food, such as injured prey.
Mochizuki hypothesized that the flies were being tricked. He believed the flowers were emitting a scent similar to that of a wounded ant. The flies would land expecting an easy meal, only to become dusted with pollen. They would then visit the next deceptive flower, carrying the pollen with them. This form of mimicry is not new to the plant world; for example, the parachute plant mimics the scent of an injured honeybee, and some Aristolochia plants smell like hurt plant bugs to attract similar insects.
The behavior of the fly is linked to a strategy called kleptoparasitism. Kleptoparasites do not hunt their own food; they steal meals from other predators. A grass fly might observe a spider attacking an ant and then swoop in to drink the fluids from the injured ant. Mochizuki believed the dogbane flower was sending a false alert, pretending to be a location where an ant was injured. This attracted the flies to a spot where no injury actually existed.