Some carnivorous plants change their scent to attract different types of prey, mimicking flowers in their luring techniques, and maybe even regulating their digestion.
Trumpet pitcher plants, or Sarracenia, get their nickname from their design 鈥� their leaves have evolved into the shape of pitcher-like cavities into which insects trip, falling deep into corrosive, digestive liquid they cannot escape.
Botanists have long debated how these plants manage to lure insects into their leafy trap in the first place: the colour of their green funnels can be attractive to arthropods, as can and their , but the scientific jury is out on which one is most important. The size of the pitchers in determining which types of prey come to their death, with bigger pitchers catching larger flying insects, like butterflies and moths, and smaller pitchers imprisoning ants, flies and midges.
Advertisement
Researchers have now found that scent is an important determiner of the kinds of prey these plants capture 鈥� and they may be able to fine-tune it to their liking. The researchers analysed the molecular makeup of scents emitted by 16 different plants from four species of Sarracenia and matched that up with the partially digested creatures found in the plants鈥� pitchers. They found that, although pitchers are 鈥済eneralists鈥� trying to attract a wide range of prey, slightly different perfume recipes were correlated with different catch of the day.
鈥淭hese findings suggest that these carnivorous plants are not simple passive plants with random captures and that they can target their prey,鈥� says at Montpellier University in France.
Species that emitted more chemicals usually found in the scents of fruit and flowers, like monoterpenes and benzenoids, attracted more pollinating insects, while those emitting scents with fatty acids were more alluring to ants. It isn鈥檛 clear whether these insects actually prefer these kinds of odours.
Plants from the same species emitted different scent cocktails too, which may have something to do with the digestive state of the pitcher. 鈥淢aybe, once a pitcher has captured enough prey, it changes or reduces its olfactory signal in order to avoid indigestion,鈥� says Gaume. 鈥淢aybe will it stop emitting monoterpenes to stop catching large flying prey?鈥�
These are leaves acting like flowers, says to , director of the Max Planck Institute for Chemical Ecology in Germany, who wasn鈥檛 involved in the study. 鈥淚t鈥檚 impressive that it鈥檚 the same group of compounds that flowers use 鈥� they鈥檙e playing with the same stuff,鈥� he says. 鈥淭hese plants are somehow clued in to say, 鈥極kay, time to smell good, time to get something in there.鈥欌��
The next step, he says, is to run experiments to understand how significant the differences between the scents are, and whether elements like environment, microclimate and competition make a difference in this carnivore鈥檚 selected eau de parfum.
PLOS One
