(CN) — A daisy living in Namaqualand, a desert environment in northern South Africa where it rains only during the winter, has a few weeks to bloom, pollinate, and set seeds before the area becomes too dry for it to live. All the while, it must compete with other flowers to attract pollinator flies.
So it does what any self-sufficient daisy would do to survive: it seduces male flies by pretending to be a potential mate.
According to a study by Beverley Glover, a professor at the University of Cambridge’s Department of Plant Sciences and the director of the University’s Botanic Garden, and her team, the daisy known as Gorteria diffusa combines at least three preexisting genes to "create" lifelike female flies.
They published their findings Thursday in Current Biology.
Glover and her team found the gene that moves iron in the daisy changes some of its normally reddish-purple petals to a “more fly-like blue-green.” Meanwhile, the gene that grows hairs on the daisy's root causes the the petal hairs to expand, giving its fake female flies texture.
To further add realism to its fake female flies and draw in unwitting and mating-focused male flies, Glover said the daisy has its fake flies appear seemingly at random — thereby avoiding looking like a patterned, spotted flower.
“The thing that’s clever here is that these flowers have 12 to 14 petals, and you only get the spots on two to four of them that look totally random in position. That’s what the fly is doing. They’re looking at it and going, ‘Oh, that’s random. That’s not part of the plant. It must be a lady fly,’” Glover said in a phone interview.
The male fly then lands on top of the "lady fly" and wiggles around in a vain attempt to mate. Eventually he gives up and flies away, but all the wiggling gave the daisy what it needs to survive — pollen.
She also noted the daisy creates the flies in a spiral pattern which she compared to a clock, with a fake fly petal appearing at 12 o’clock, then another at 4 o’clock and so on to give it the “appearance of being random but it’s not random at all.”
Glover said that she and the team do not yet fully understand how these three genes came together in evolution or what the other components are, but they can do so by studying the daisy’s relatives, some of which have simpler spots while others don’t have spots at all. Also, further study of the area can aid in the conservation of the "biodiversity hotspot" Glover and her team call “Cape Flora” — one of the most species-dense regions on the planet, especially after climate change.
“This area is such a delicate ecosystem, and we think that a lot of the species diversity in it, all of the amazing different species that are there, are coming because of the particular combination of habitat types,” Glover said.
She attributed the area's delicate nature to "the winter rainfall, the summer desert, and there are a lot of fires in that habitat too. And certainly, we’ve seen over the last few years, South Africa has had terrible droughts. In 2017, they had a terrible drought that was really worrying because nothing grew that year, and with climate change these flowers are probably at risk along with the animals that depend on them too," she said.
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