MeatEating Plant Steals Bugs From Neighbors
PUBLISHED March 5, 2018
Finding a sundew plant with a healthy supply of insect food may not seem suspicious. After all, carnivorous plants are famed for supplementing their diet with meat to compensate for nutrient-poor soil.
But there may be devious behavior going on behind the scenes. Some sundews growing in bogs in Japan steal insects lured by the flowers of neighboring plants, according to Kazuki Tagawa from Kyushu University in Fukuoka, Japan, and his colleagues.
It seems to be a case of kleptoparasitism, which has only previously been witnessed in animals, where food is acquired from another species with nothing offered in return. For instance, frigatebirds steal their meals from red-footed boobies.
âAs far as we know, this phenomenon has not been observed before,â says Tagawa, whose team reports their findings in Ecological Research.
The researchers investigated how two sundew species, Drosera makinoi and Drosera toyoakensis, attract prey. They looked at the role of the sundewsâ own flowers, as well as those of plants close by, and compared the number of insects trapped when flowers from one or both types of plants were removed.
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Surprisingly, the number of insects they caught depended on whether the surrounding non-carnivorous plants had blooms. Thatâs odd, since the non-carnivorous plants donât benefit from associating with sundews, and instead are investing resources in their own flowers only to see potential pollinators become prey. (Find out how sundews also compete with spiders for prey.)
Meat-eating plants rely on insects for reproduction, too, so itâs not always an advantage to eat them. Many have evolved mechanisms to spare some prey, for example, by having traps that only function after the plant has flowered. The sundew species observed in this study, however, can make seeds from their own pollen.
âItâs better for them to trap pollinators and get more nutrients,â Tagawa says.
He and his colleagues plan to follow up to see if preying on pollinators is having a detrimental effect on the neighboring plants. (Read about sundews in Sweden that are getting âfullâ on nitrogen pollution.)
Joni Cook at Loughborough University in the U.K., who also studies the feeding habits of sundew plants, is interested in whether the plants are accessing more nutritious prey by thieving from others. If so, sundew survival might be affected by extreme weather and rising temperatures, which could reduce the number of pollinators their neighbors attract.Read More...