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Thorn Mimics & Other Freaks of Nature

16 Sep
A thorn-mimicking tree hopper on a branch (Membracidae).

A thorn-mimicking treehopper on a branch (Membracidae).

Membracids (commonly called treehoppers) are one of my favorite bugs–and one of the few smaller insects that I will consistently take the trouble of snagging for my collection.  At the start of my journey into entomology I can recall being deeply impressed by some thorn-mimicking treehoppers pointed out to me on a branch.  They look like thorns!  They run around the branch and try to hide from you!  They hop!  What’s not to love?

Oh, and a good number of membracid nymphs have mohawks.  That’s pretty freaking adorable, right there.

These little guys are incredibly diverse.  Here’s a picture that’s not mine:

Morphological variation in membracid helmets.

Variation in treehopper morphology (Photo credit: Prud’homme et al 2011).

Not only are there thorn-mimics and brightly colored aposematic hoppers, but also feces and even ant-mimics.  The treehoppers that look as if they have sprouted entire mutant ants from their back are some of my favorites.

Now, I was taught that this structural diversity came from variations in the pronotum, but it turns out membracids are even more interesting than that.  Recent research has provided evidence that the helmet structure is actually a novel appendage, entirely unique to the genus.  This structure is apparently something like a modified third wing, the presence of which may be a result of mutations to the Hox gene complex.   (This is the same group of regulatory/developmental genes that can cause mutant flies to sprout legs in the place of antennae and such.)  A very cool example of evolution in action!

See also: Ants & Hoppers