Common Beans
A study conducted between 2023 and 2024 in the Mexican state of Oaxaca revealed that the common bean species Phaseolus vulgaris—which includes red, black, and white varieties—can release volatile compounds that attract wasps. These wasps then prey on caterpillars, effectively shielding the plant from pests. A receptor on the leaf surface plays a crucial role in this process by detecting the peptide inceptin, a substance found in caterpillar saliva.
Experiments and Findings
During the experiments, some bean plants were treated with caterpillar saliva, others with the pure In11 peptide, and some were mechanically damaged and moistened with water. Dead caterpillars of the species Spodoptera frugiperda were also attached to the plants. The results showed that plants lacking inceptin receptors attracted 40% fewer wasps after being exposed to caterpillar saliva or the In11 peptide. In contrast, no difference in wasp attraction was observed following simple mechanical damage.
Laboratory experiments confirmed that without inceptin receptors, plants fail to produce the characteristic blend of volatile compounds. The researchers noted:
“Inceptin recognition not only amplifies the response to damage but also triggers a separate immune mechanism that leads to the release of a specific mixture of volatiles to attract predatory wasps.”These findings open up new avenues for understanding the interactions between plants and their natural enemies.
This research, carried out in Oaxaca, underscores the importance of biological mechanisms that enable plants to defend themselves against pests. Studying such plant–natural enemy interactions could help develop new pest control strategies in agriculture, reducing reliance on chemical pesticides. That would benefit both crop yields and the ecological sustainability of farming systems.