Life can be rough when you’re a plant - all of those cruel herbivores going about their daily business, munching on your leaves that you’ve spent so long growing. Of course, some plants possess defense mechanisms to avoid such situations, like toxins or sharp spines. So how do plants that don’t possess such features avoid becoming victims of chomping jaws?
The animal kingdom is full of examples of how to do this - mimicry. Mimicry is where an organism has adapted over time to appear similar to another object or organism. This might be to appear dangerous in order to send out “don’t eat me” signals, or alternatively to camouflage themselves in order to blend in with their surroundings.
There are a few known examples of mimicry within plants. For example, Australian mistletoes mimic the leaves of their host tree. Now there’s a new plant-like chameleon on the loose: the woody vine Boquila trifoliolata.
Endemic to Chile and Argentina, B. trifoliolata is the first documented example of a plant that exhibits mimetic polymorphism, which is the ability to mimic multiple different host species. Researchers found that when this vine was climbing a tree it was able to imitate the host leaves in terms of size, shape, color, orientation and even vein conspicuousness. The study has been published in the journal Current Biology.
When the vine was not climbing a host, or was associated with a leafless trunk, the leaves of the vines were found to be the same. Furthermore, when a single vine was associated with multiple tree species, it was able to sequentially mimic these different hosts. Mimicry was also observed when the vine was not even in contact with the host.
To find out if this bestowed the vine with benefits in terms of herbivore avoidance, researchers investigated whether herbivory differed when the plant was associated with different hosts. The main herbivores that eat these vines are weevils and leaf beetles, both of which rely on vision and smell to forage. They found that herbivory occurred to a greater extent on vines that were not climbing a tree when compared with vines that were associated with leafy trees. Vines that were climbing leafless trunks experienced the highest rates of herbivory.
Currently, the researchers do not know how this vine achieves this super-mimetic ability, especially since it can occur without contact with the host. They postulate that it could be due to the release of volatile organic compounds by the host species which could trigger changes in the vines, but more research needs to be carried out to ascertain whether this is the case.