Watch the delightful moves of these wooly beech aphid nymphs (aka "Boogie Woogie Aphids") getting down on the branches of an American beech tree, from Bug of the Week's YouTube page. It's like a buggy rave, where everyone is dressed in white furry outfits, minus all of the glow in the dark accoutrements.
What's going on here? Joe Boggs of The Ohio State University's Buckeye Yard and Garden Online explains:
Beech blight aphid nymphs exude tufts of white, wool-like filaments from their posterior ends. Large numbers of these native aphids gather together in prominent groups that are commonly called "colonies" on the twigs and branches of American beech. The colonies appear as masses of white, fluffy material adorning the twig and branches of their namesake host.
When disturbed, the entire colony will pulse their woolly derrieres in unison in what appears to be a synchronous samba. This peculiar behavior has earned the aphid the alternate common name of the "boogie-woogie aphid." I believe no other insect upstages beech blight aphids in entertainment value.
It is speculated that the mass-wiggling of beech blight aphids distracts or dissuade predators and parasitoids from focusing on single individuals. Although I could find no published research where this defense theory was tested with this aphid, the collective motion of prey to lower the targeting success of predators has been documented with other animals.
On the other hand, research has been published showing beech blight aphid nymphs practice another far more unusual type of defense strategy. The nymphs are highly aggressive against predators and will mass-attack using their piercing-sucking mouthparts to inflict serious damage to their assailants.
You can see lots of photos of the aphids at various seasons throughout the year at The Ohio State University's Buckeye Yard and Garden Online page here, and watch another video, "Sooty Mold & The Boogie Woogie Aphids" (sounds like a band name!) of the bugs dancing here, from Learn Your Land:
This was probably the coolest thing I saw in the woods today — an intimate relationship between the American Beech tree (Fagus grandifolia), the Beech Blight Aphid (Grylloprociphilus imbricator), and the Sooty Mold Fungus (Scorias spongiosa)