This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
To ease on in to the weekend, let's celebrate by watching some short films on a topic that I mentioned earlier this week in my planthopper post: plant bug poo, aka honeydew. It's not as gross as you might think.
Plant bugs feed on plant sap, which is seriously low in protein. In order to get enough, they have to drink/filter a LOT. As a result, they end up excreting a lot of what is essentially unwanted sugar solution. And lots of other things are interested in eating the leftovers. Before you implement your gag reflex, remember that North Americans eat something similar (albeit not passed through a bug's nether regions) when we eat maple syrup, which is boiled, condensed maple sap.
Now, lots of things can happen to all this honeydew. Here are a few options:
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First, the bug can fling it away with a special flicker (not actual name, I'm sure). These are leafhoppers, which are relatives of the planthoppers I discussed on Wednesday.
To see it even more clearly, watch the bug on the right in this video. He(she) seems to be ever-so-considerately flinging his poo over the top of his(her) neighbor:
But what if you could actually get something in return for making all that honeydew? Well, plant bugs called aphids are all over this. As you may have heard, many of them feed ants their honeydew in return for security services. The aphids in this video look as happy as hogs in slop, as we Yanks like to say, and about as burrowed in. I'm not sure what the ants are doing "spooks" the aphids, but they do seem to signal to them somehow that they'd like a drink. You can see what you need to in about the first minute of this video. But if you've had a particularly rough week, just close your eyes and listen to the rest of the video's beautiful backyard birdsong soundtrack. Really.
Finally, we have a few vertebrates that have figured out that honeydew is, er, the bee's knees, so to speak. Here are two videos of geckos snacking on honeydew. The first is from David Attenborough, without whom no weekend can ever really start.
And here is a much more obnoxious American production by National Geographic. It does a great job of showing the mess that piles up when honeydew isn't consumed right away. As well, note those "flatid bugs" that look like they're having some sort of bad Don King hair day. Those are juvenile planthoppers, the same group of organisms I covered earlier this week. The "Don King hair" is made up of waxy secretions. As I mentioned, many plant bugs can secrete wax, and apparently, in this particular case, said secretions don't taste so good either. See here for more details, including photos of their vastly different looking adult forms. Must be seen to be believed.
Finally, to complete your moment of zen, here is a gorgeous photo of one other thing that can happen to honeydew: consumption by a sooty mold fungus. On this eucalyptus, scale insects, another kind of sucking, pooping plant bug, are the guilty party. The sooty mold is the black film on the leaf at right. Since it's eating honeydew, and not the plant, it's chiefly a cosmetic issue if you're a gardener. Those white scale insects are your bigger problem.
Note the ants. I bet I know what they're after.
