Note this bee observation: only two species of bubblebees do this. This a specialized instinct:

https://www.sciencedaily.com/releases/2020/05/200526134651.htm

In these experiments, the researchers again observed that hungry bumblebees with insufficient pollen supplies frequently damaged the leaves of non-blooming plants. But the damaging behaviour was consistently reduced when the researchers made more flowers available to the bees.

Furthermore, it was not only captive-bred bumblebees from the researchers' experimental colonies that damaged plant leaves. The investigators also observed wild bees from at least two additional bumblebee species biting the leaves of plants in their experimental plots. Other pollinating insects, such as honeybees, did not exhibit such behaviour, however: they seemed to ignore the non-flowering plants entirely, despite being frequent visitors to nearby patches of flowering plants.

Comment: Why only bumblebees? Do only they have the humanized-style brains to figure this out?