With external stomachs and a coating of deadly digestive goo, carnivorous plants can reduce their prey to dust in a matter of hours.
- Scientists in WA have developed a DNA test to identify the bodies of bugs eaten by carnivorous plants
- It has previously been difficult to determine what the plants are eating because the bugs are digested so rapidly
- WA has the highest number of carnivorous plants in the world, according to the lead researcher
Scientists have long had trouble trying to detect exactly what the plants have eaten because of the state they leave their victims in.
The plants use enzymes to digest the bugs that are trapped on their sticky surface, which doubles as the plant’s stomach.
“Insects that are stuck on a leaf are very, very rapidly digested — like within hours they can become completely unidentifiable crumbs,” Curtin University PhD student Thilo Krueger said.
Mr Krueger and his fellow researchers have developed a new DNA test that takes genomes from the “crumbs” on sundew plants and compares them with a database of known insects.
Scientists from the Botanical and Zoological Natural History Collections in Munich and the University of Munich were also involved in the project.
Many species under threat
Mr Krueger said the new method enabled scientists to collect crucial data on how the plants survived so steps could be taken to protect them.
“Many, many species in Western Australia are quite severely threatened by habitat loss, by environmental pollution and also by climate change, especially in those areas that are getting drier and drier,” he said.
The researchers tested the method in the Kimberley region on a variety of sundew with large leaves that made it easier to see the remains of bugs.
Prior to the Kimberley study, Mr Krueger said scientists had not known if the insect remains left by the plants would even contain DNA.
The results showed the sundew’s main food source was flying insects.
“We found butterflies, we found bees and wasps,” Mr Krueger said.
Mr Krueger said the number of cicadas was unexpected, because they had been rarely found on the plants in previous studies that used traditional methods.
Why so many in WA?
WA has about 120 to 130 species of sundew species, compared to just three sundew species in all of Europe.
It is believed the high number of carnivorous plants could be because of the nutrient-poor soil in many parts of WA, which forces plants to seek nutrients from the bugs they eat.
Mr Krueger said the climate in WA had also remained stable compared to many other regions.
“[WA] hasn’t been, for example, covered by a glacier,” he said.
Mr Krueger moved to WA from Germany to study the plants.
He said he expected scientists in other parts of the world would begin to use the DNA identification method.
“The South American and African regions have many, many, many species and they are similarly under-studied,” he said.
Mr Krueger said the scientists combined the DNA testing with very high-resolution photographs.
He said the photographs was used as a “control” to ensure that the results were not influenced by bugs that touched a plant but were not eaten.