Ants farming helmeted treehoppers
The treehoppers are related to plant hoppers. They spend their life sucking plant juices.
To get the amount of protein they need they end up taking in more sugar than they need. The extra sugar is excreted, which the ants like, so they tend to the hoppers and protect them. Treehoppers provide nectar for the ants and in return the ants protect from predators-- like wasps.
The "helmets" in this group of treehoppers are highly modified homologs of wings. A long repressed winglike structure that has appeared again to take on a variety of new functions.
The "helmet" on the back of this species appears to mimic ants (there are some actual ants attending them too).
Photograph by Craig Knox
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