Researchers at the University of Delaware have recently found that agricultural plants send out sensory volatile cues that alert organisms in the area (such as birds) that they are in need of help. Previous research has shown that this occurs in ecosystems such as forests. These “signals” are sent when plants are under siege from insects. With a little Play-Doh and orange colored pins, they are seeing the potential for growers to defend their crops.
Play-Doh "larvae" were distributed onto plants around a volatile dispenser that released the odor and recorded how many bird pecks were on the larvae closer to the volatiles versus the organic solvent dispensers. The results were clear: There were significantly more attacks on the larvae closer to the volatile dispenser.
It has been known for years that parasites and predatory insects respond to the damaged plants that release volatiles. With this new evidence of birds using the same cues, it allows a better understanding of their behavior. This information will be crucial when creating pest management programs. Interestingly, when scientists compared the number of pecks on the larvae attached to the volatile dispenser and the number of pecks on the surrounding plant larvae there was virtually no difference. That means the birds are smelling the volatiles and when it gets close to the damaged plant it visually searches for the insects.
It has been a longheld belief that birds were unable to smell. However, this research indicates that they are smelling the volatiles and then coming in closer to visually locate their prey. Birds lack certain anatomy to be able to smell yet somehow they are able to sense the volatiles emitted by the plant. Researchers will be testing to see which species of birds have this capability using essentially the same experiment as above.
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