Scientists Choose Their Favorite Galls
If you study insects, you know about galls – yet scientists still have as many questions as they do answers about these insect-made structures. A gall is built by an insect using only chemicals, starting with a drop saliva deposited on a leaf.
A tiny home for their young, this amazing DIY project grows out of a combination of chemicals from the bug and from the tree. Until their young are hatched, the gall is a safe home that also offers a food source.
Galls found in the western states include a variety found on grapeleaves and two found on oak tree leaves.
The grapevine phyllorexa leaf gall comes from an aphid-type insect that became notorious over a century ago for almost wiping out grape crops. But this insect also possesses a unique ability, via the gall, to improve the plant’s capacity to breathe by reconfiguring the leaf’s stomata.
Two other types of galls to look for is the beaked twig gall, found on oaks (both scrub and blue varieties) and having a unique shape and pattern. Another type of gall found on oak tress is the Crystalline gall. These can blanket the entire surface of the leaf and at first glance, look like a covering of pink or red caterpillars. The Crystalliine gall is found on white, blue and valley oak trees.
The list of gall types goes on – look for them in forests near you.