Green Spittlebug from Spotted Knapweed

2011 November 12

We have a lot of spotted knapweed [1] growing alongside the road. In June, pretty much every stalk of it has a blob of spittlebug spittle on it, with one or more of the green nymphs inside. This year, Sam collected a stalk with a nice spittle blob on it, and put it in a vase of water so that we could see what an adult spittlebug looks like. Here’s what one of the blobs of spittle looked like as of June 29, 2011:

The spittle was a bit dry and crusty at this point, and if it was held up to the light, it was possible to see the outline of an adult spittlebug perched inside (I circled it to distinguish it from buds on the plant stem):

When I gently touched the spittle (which was dry and brittle), the spittlebug inside exploded out with an audible “pop”, like a piece of tiny popcorn. Luckily, this was in the kitchen, and there was a large stainless-steel bowl that the bug landed in. Otherwise, I probably never would have found it. So, here it is:

The adult form of a spittlebug is a “Froghopper” (so named because their heads and eyes look kind of froglike), in the family Cercopidae. They closely resemble Leafhoppers (family Cicadellidae), except that leafhoppers have spines on their hind legs (and their nymphs don’t make spittle blobs). This particular spittlebug still has a blob of foam on its face, probably because it blasted through the dried spittle headfirst.

The jumping legs aren’t all that large (not like, say, grasshoppers), but that doesn’t stop them. This one jumped probably 3 feet from the plant to the bowl, and yet it is a little thing only about 4 mm long.

I was watching one of them crawl a while back, and noticed that the two hind legs don’t get used for walking. It used the four front legs to walk, and was just dragging the cocked hind legs behind it. When it wants to jump, it just releases the hind legs with a “pop!”, and it’s off. I see it also has wings, and I assume that they can fly in a controlled sort of way, but I’ve never seen one do it. They certainly don’t use the wings when they jump, they just tumble along on a ballistic trajectory until they hit the ground.

Some spittlebugs are considered pests, because they feed on valuable crops. In this case, though, it’s on a plant normally considered a noxious invasive species, so in this case the spittlebug would be considered neutral-to-beneficial by most people. Some spittlebugs are plant-specific, and some are not. According to the experts on Bug Guide, this one is a Meadow Spittlebug, Philaenus spumarius, a very widespread species in North America. And it turns out to be yet another accidentally-introduced European species. It figures. Meadow spittlebug adults are very variable in coloration, and this particular one just happens to be at the green, nondescript end of the spectrum. Meadow spittlebugs are generalist feeders, so if one has crops, then it is a crop pest. Locally, though, it looks like it mostly feeds on a number of common invasive plants. I think it is the same one that we commonly see feeding on Tansy (another aggressive invasive species locally), although it is probably also the one that we see on our strawberries sometimes.

[1] Spotted knapweed (sometimes called “star thistle”) gets established in dry areas where other plants don’t grow, particularly the sides of roads. It then expands into fields and pastures, where it is considered a noxious weed because animals like cattle, horses, etc. don’t like to eat it. It also tends to force out the native plant species. Roadsides are a prime conduit for all sorts of invasive species: I sometimes look at the plants alongside of our road, and the plants are mostly Spotted Knapweed, Queen Anne’s Lace, Tansy, Goldenrod, European Thistle, and White Sweet Clover – of which only the Goldenrod is native.

Although, as a beekeeper, I’m a bit torn; all of those plants have flowers that are excellent honey sources. I see both my bees and the wild bees working the flowers pretty heavily all through late summer and part of the autumn.

7 Responses
  1. November 12, 2011

    Does it have sufficient dexterity in its forelegs to clean the dried spittle off of its face?

  2. November 13, 2011

    You know, now that you mention it, I’m not so sure that it could wipe its face. Between its inflexible neck, and the way that its legs were jointed, and their overall stubbiness, it doesn’t look like it was physically capable of getting its forelegs up onto its face at all. And, I would think that if it could have done it, it would have wiped its face immediately rather than leaving the stuff on for the several minutes that I spent taking pictures of it.

    In the wild, they may very well have to wait for the spittle to gradually wear/wash off.

  3. November 13, 2011

    When I looked at the photos, it seemed as though the legs were too short to reach the face adequately even if they had the dexterity. If that’s the case, this one is at a severe disavantage as its vision must be terrible.

  4. November 14, 2011

    While I’m sure it would be better off if its eyes were clean, I’m not so sure that these guys see very well in any case. When I find them out in the grass, they don’t seem to be alarmed by my approach, and don’t even respond to my presence unless I touch them (at which point they explode into the air). They could do that even if they were stone blind.

  5. November 14, 2011

    In my yard, spittlebugs like the evening primroses. Very annoying.

  6. Carole permalink
    November 15, 2011

    Wonderful information. I’m sure they make good reptile and bird food.

  7. November 19, 2011

    I’m thrilled to read this post having pinched a few of these in my day. I’m not sure now, however, that I’ll be able to continue to pinch them. Your photos show me that its indeed a handsome critter, which I had been perfectly able to ignore.

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