“Stayin’ Alive”: Tricks Insects Use
By Bruce Rottink

Agromyza vockerothi
Leaf miner on Thimbleberry Agromyza vockerothi
Agromyza vockerothi  is a leaf miner fly in the family Agromyzidae.
One secretive insect life style is that of the leaf miner.  These flies have it made. The female fly lays her eggs on the leaf, and upon hatching, the larvae burrow into the leaf.  They spend their entire larval life inside the leaf where they eat only the most nutritious parts.  It is like you living inside a giant hamburger, eating your way from one place to another.

In the process of munching through the leaf, the insect kills lots of leaf tissue, which eventually turns brown and marks the course of the leaf miner’s journey.  As you can see in the thimble berry (Rubus parviflorus) leaf below, the larval track starts out very small (upper right), and increases in size as the larvae grows bigger and works its way through the leaf.  At the end of the larval stage, it emerges from the leaf, often leaving a noticeable hole.  (Not all the holes in this leaf are associated with the leaf miner.)