Record-breaking tiny organism discovered that spreads seeds by eating them

Earwigs and woodlice just got a little more special. New research shows that these creatures can spread seeds by eating them. This would make the woodlouse the smallest species ever capable of this.

They can be found under every paving stone: woodlice. And although we in the Netherlands are not too impressed by these creatures, things are slightly different on the other side of the world. For example, a Japanese study shows that both woodlice and earwigs are able to eat the seeds of the ‘Silver Dragon plant’or the Low monotropastrumto eat. And not only that; the insects also poop them out and thus help the plant to spread its seeds.

New seed dispersers
Scientist Kenji Suetsugu contributed to the research. He says: “We tried to find new ecological interactions by focusing on the smaller life forms. Finding these new seed dispersers invites science to rethink old strategies. In addition, this research once again proves how important it is to ensure that diverse habitats are preserved.” The research has been published in the journal Plants, People, Planet.

Fruity benefit
For the study, Suetsugu’s team specifically looked at the Silver dragon plantor the Monotropastrum humil. This plant is found throughout East Asia and is known for its tiny seeds. However, it was not yet known how the plant could propagate itself, as the seeds are safely stored in a fruity covering. The researchers therefore decided to collect a number of copies of the Silver dragon plant keep an eye on it by automatically photographing it at night. Afterwards, they looked at the photos to see which animal species enjoyed the fruit the plant produced the most.

This analysis shows that cave locusts ate more than half of all fruit. This strain also ended up destroying the least number of seeds – this is important for the plant’s reproduction. In addition to cave locusts, the research showed that earwigs and woodlice also liked the fruit very much. These species keep about 30% of all seeds intact. During a final step before the research, the scientists looked at whether the seeds of the Silver Dragon plant through the digestive tract of earwigs and woodlice. This turned out to be indeed possible. It suggests that earwigs and woodlice therefore play an active role in the dispersal of seeds of this plant.

The fact that animals can spread plant seeds by eating them and then excreting them again is not in itself new. Scientists know that many animals – such as birds, but also for example fishing – help plants in this way to distribute their seeds – sometimes over great distances. But what makes this new research so special is the size of the seed dispersers at its center; Never before have researchers seen such small organisms disperse seeds by eating them and excreting them again.

Earwigs and woodlice therefore seem to be able to eat the seeds of M. humble and then excrete part of it – about 30 percent – in one piece – and thus contribute to the spread of those seeds. But the research also reveals that about 70 percent of the seeds consumed by earwigs and woodlice should be considered lost. However, according to the researchers, this is not immediately a problem. They suspect that it is ultimately beneficial for the plant if woodlice and earwigs can also help disperse the seeds.

The discovery that the earwig and woodlouse, which are little appreciated by many, can play such an important role for plants, leaves us wanting more and makes researchers suspect that there are even more small seed dispersers waiting to be discovered. Suetsugu concludes: “Some species were previously classified as ecologically insignificant. We are therefore trying to find more species that have similar seed dispersal mechanisms. In this way we hope to reveal an ecological phenomenon that is currently overlooked.”