Thursday, June 16, 2011

Red Bumps on a Silver Maple Leaf - Maple Bladder Galls

These red bumps on this Silver Maple Leaf are Maple Bladder Galls, caused by the minute mite Vasates quadripedes.  I won't go into much detail about galls or the mite that creates these galls in this post. If you want more information, go to this site from Penn State University or this site from Washington State University.  I looked at a number of these galls under my dissecting scope to see the Eriophyoid mites that cause them.  Below is what I found.

The picture above is a cross section of one of the galls.  They are hollow on the inside, with the inner surface being lobed or bumpy.

This is a view of the gall with the top cut off.  Inside of almost all of the galls were many tiny eggs or immature mites (I'm not really sure which) that didn't move and resembled miniature, yellowish, translucent grains of rice.  Also, in most galls there were larger, miniature, translucent grains of rice that did move and had legs or other appendages.  Some of the galls had very active mites that sort of got away from the rice resemblance, but they were still very minute and just as translucent

According to the sources that I consulted, Eriophyoid mites have two pairs of legs and in this case, are carrot shaped.  The ones that I saw moving about seemed to have more legs and weren't always what I would call carrot shaped, but they were so small that I had my dissecting scope zoomed in all of the way and it was tough to keep them in focus.  I've never looked into a gall with magnification before; it was fascinating to see this hidden space. 

I read that the mites enter the leaf through the underside, and that a small hole can be seen under the gall where the mite entered the leaf and began feeding.  I looked and the holes were not only visible under the scope, but were visible to the unaided eye.  But what really caught my eye under the scope was the venation of the leaf.  I was really surprised at how beautiful the colors and patterns of the leaf veins were with the magnification of the dissecting scope.