Return along the path continuing past the place where you entered. You will eventually find in the path another of those plants with the long stems and palm leaves. This one has the leaves closed; click on the orange bump at the base and they open, shading the open blue plant with the insect cloud. You can hear it closing. Go back along the path and you will see that it has indeed closed, but the insect are still there. Keep going until stopped by a hollow blue root. This must be the runner from which these blue plants grow. You can go over to the big blue plant to examine the brown ones; click on the largest of these and it emits a cloud of spores that drive the insects away. (If the plant is not closed the insects will not leave.)

noxious puffer plant