NMNS Fossil Plant–Insect Interaction Database

Q3.: How can we tell that a mark on a leaf is insect feeding rather than accidental damage?

A3.: One key line of evidence is the repeated occurrence of the same pattern across multiple areas or specimens.

Explanation

A single insect typically repeats a characteristic feeding behavior on a leaf. As a result, bite marks of similar size and shape often appear in comparable positions on the same leaf, or recur in similar patterns across different leaves from the same locality. This regularity is unlikely to result from chance damage and instead reflects selective and patterned feeding behavior.

In addition, if reaction tissue is present along the damaged margin, this provides especially strong evidence that the leaf was eaten while the plant was still alive.