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From time to time, I mention the umbrella magnolia (Magnolia tripetala) in my back yard. It even earned its own diary a year ago. When I'm in the yard, I can't help but notice the enormous leaves. Things that happen on trees with smaller leaves might be easily overlooked.

The Daily Bucket is a regular feature of the Backyard Science group, a place where everyone is welcome to note the observations you have made of the natural world around you. Insects, weather, fish, climate, birds and/or flowers: all are worthy additions to the bucket. Ask questions if you have them and someone here may well have an answer. All we ask is that you let us know where you're located, as close as you're comfortable revealing.
One day last week, I noticed a squiggly trail on one of the leaves. It looked very much like an aerial view of the twisting course of an undammed river. Having taken entomology in a century long ago and far away, I knew the the culprit was a leaf miner. And like so many things in nature, it's not easy to know which species, because there are so many different types of leaf miner.

The first two pictures were taken June 5.

leaf miner on umbrella magnolia

As thin as a leaf is, the leaf miner still excavates a trail that is barely visible from the underside of the leaf.

back side of umbrella magnolia leaf, with leaf miner damage on other side

By June 11, more leaves were affected, and the trails had grown.

leaf miner on umbrella magnolia

A closer look reveals two insects. The one on the right is some type of beetle. I cannot resolve the insect on the left well enough to know whether it has two wings or four. There is an outside chance that it is the adult form of the leaf miner.

leaf miner on umbrella magnolia, with bonus insects

Another leaf has also been invaded.

leaf miner on umbrella magnolia

What's causing the damage? The culprit is at the bottom of the next image. Also, take another look at the first picture, and a larva can be seen on the left side of that image.

leaf miner larva on umbrella magnolia

When fully grown, the larva creates a cocoon and begins to pupate.

leaf miner pupa on umbrella magnolia

Pupa and larva, with scale. The pupa is about 4 millimeters in length.

leaf miner pupa and larva next to millimeter scale

Identifying the insect is above my pay grade, considering that nobody is paying me to do this. A quick check of Wikipedia reveals that there is no shortage of suspects:

A leaf miner is the larva of an insect that lives in and eats the leaf tissue of plants. The vast majority of leaf-mining insects are moths, sawflies and flies, though beetles and wasps also exhibit this behavior.
Looking at the BugGuide larva images, I see resemblances to the ones that are classified as moth larvae. One of our resident experts might be able to help.

How is my little tree with the giant leaves progressing? A year ago it was 3 feet tall.

Umbrella magnolia

Now it's 7 feet tall, with new branches, and plenty of leaves to attract munching insects.

Umbrella magnolia (Magnolia tripetala)

That's the latest news from my back yard. Now it's your turn.

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