Bees are a flower's best friends: The insects land on flowers that catch their eye, pick up pollen with their sticky feet, and spread the plants' genetic material far and wide. Scientists have even shown that, in the Northern Hemisphere, flowers' coloring patterns evolved specifically to meet the nuances of insect vision. To test whether the evolutionary link between flowers and insects holds true in Australia, which has been geographically isolated for 34 million years, scientists collected 111 native Australian flowers. They analyzed the color patterns—not just in the spectrum of visible light that humans can see, but also the reflection of ultraviolet light that insects are sensitive to. The yellow jessamine (Gelsemium sempervirens, above), for example, appears entirely yellow to humans but has broad color variation to bees. Echoing previous studies from the northern part of the world, the Australian data, published today in the Proceedings of the Royal Society B, shows that flowers Down Under show the most color variance in the narrow spectra that insects are most sensitive to. This helps an insect distinguish flowers, remember their favorite, and return to it—good news for the plant. The results, now replicated on two continents, likely hold true elsewhere as well.
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