Plants produce different odor depending on the type of herbivore attacking it, meaning that if a native plant is attacked by a foreign herbivore it emits an odor different from that of a native herbivore.
Study with 12 herbivores
Science was always amazed by the survival ability of plants. One such survival hack is the ability of plants to produce bouquet. To everyone’s interest, they even emit a variety of different odors under attacks depending on the type of enemy. A plant might emit an odor to alert parasitic wasps to let known that there are caterpillars on their system, which in long run eliminates percentage population of both caterpillars and wasps.
In order to verify the claim, scientists from Radboud University and the University of Neuchâtel in Switzerland tested 12 different types of herbivores including native & foreign, sucking & chewing, specialists & generalists. They used high precision gas chromatography from the department of chemistry to identify each type of odor. An ingenious statistical model and associated calculations were in fact used by the research team to identify different bouquet responses.
The nativity issue
Two herbivores in the test pack were actually created a nativity issue, which in fact was solved after comparing with the statistical models they developed. Two species of caterpillar, the cabbage looper, and beet armyworm raised some issue whether they are naturalized or exotic. However, on comparing the odor with models, it was finally confirmed that these varieties of herbivores are indeed exotic, which in turn would determine the types of parasitic wasps interacting. Determination of exotic and native wasn’t in fact done after examining a single volatile substance, instead, a ratio of volatile factors was considered in order to identify all levels of species involved.
This is how plants communicate.
Even though plants doesn’t have any sensory organs like we do, they convey their message to wasps using the bouquet. From the study, it was clear that depending on the type of attacker the plant can produce an arsenal of bouquet or odor, which will alert their symbiotic guard to come and eliminate all. The initial idea of the study was to understand the extent of plant bouquet interaction to parasitic wasps, whether they get confused when an exotic species of herbivore interfered. According to the conclusion from the research team, the study pointed to the fact that, based on the type of bouquet produced and its difference, parasitic wasps will attack or avoid the herbivores. In fact, this knowledge will be handy in pests control and future development in the field.