Saturday, November 13, 2010

Lacewing uses lichen camouflage

Last Thursday's foray to Rhododendron Cove, blogged about HERE, produced many interesting observations. I was with Lisa Sells and her husband Steve, and a knee issue caused Lisa to hang back while Steve and I headed into the rocky crags and rough footing. In a way, I'm glad she did, as Lisa became fixated on a whopping big oak tree, and found all manner of cool things on its bark.

A mammoth Black Oak - or about any other big tree - harbors FAR more life than the average observer would suspect. There is a reason that birds such as nuthatches, creepers, and Black-and-white Warblers have evolved an up close and intimate relationship with tree bark. These birds and others forage by creeping along tree trunks, carefully inspecting nooks and crannies for goodies.

While not much appears evident, other than bark and a robust Poison Ivy vine, there is more here than meets the eye.

When Steve and I returned from the Rhododendron Cove's summit, we found that Lisa had it made it no further than the tree we had left her at. Small wonder; she noticed that some of the lichens were walking! This led her to closely scrutinize the trunk, and find all manner of cool stuff. See her excellent blog about her experience barking up this tree, RIGHT HERE.

Anyway, we were naturally quite interested to learn of her moving lichens, a clump of which can be seen in the photo above. I happened to know what was going on, having seen this phenomenon before. She had discovered larval lacewings,a type of insect that in its immature state, camouflages its body with bits of lichens.

Here we have captured one of the little brutes, so that you can better see what is going on. When on the tree, the lacewing larva moves with a plodding, herky-jerky sluggishness, and is quite difficult to notice. It's sort of like one of those cartoons, where the hunter disguises himself as a shrub, and tries to scuttle nearer his prey when it isn't looking.

When nabbed and flipped upside down, we can see the larva's lattened, ribbed body, and a few of its legs protruding. This species, which I believe is Leucochrysa pavida, slowly collects small lichen bits until it builds up an impressive shelter. This "blind" serves at least two purposes. One, it allows the tiny predator to evade detection by bigger predators such as birds. A foraging nuthatch would likely blow right by. Two, this lichen shelter eventually becomes the insect's pupal case, in which it will transform into an adult.

Lacewings are largely predatory as adults, and totally predatory as larvae. The one above slowly moves about the bark, grabbing , piercing, and sucking the life from tiny aphids and probably any other small animals that it is capable of overpowering.

Finally, after overwintering in its lichen home, the larva will transform into a gorgeous adult lacewing, such as above. You may have seen these; they are far more conspicuous than their well-hidden larvae.

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6 comments:

Janet Creamer said...

This must be the time of year to see them. Steve Willson had a lacewing larva on his Bluejay Barrens blog, too.

Linda Sekura said...

Another good reason to let little oaks become big oaks.

lisa Sells said...

You have such wonderful blogs and pictures! Your commentary in always amazing!

Jim McCormac said...

Thanks for the comments, and yes, without big trees the lacewings would suffer. And I believe late fall and early winter is THE time to look for these things; at least that's when I've seen them. And THANK YOU for all of the great camera advice Lisa, and everyone else, if you want to see better pics of the lacewing larva, go check Lisa's blog!

John Bernal López said...

Just saw one in Athens GA and found your excellent blog after googling "what is this bug I found on tree camouflaged like tree trunk". Thanks for unfreaking me out!

Mary and John said...

I think I may have seen one of these here in Ecuador. I took pictures and video and posted it here: http://johnandmarylivingitupinecuador.wordpress.com/2014/09/14/spider-beetle-or-a-bug-oh-my/

What do you think? Is it the same thing?

We love you posts and look forward to seeing more.