Clay Bolt / Carpenter Ants (Camponotus pennsylvanicus) guarding Beech Blight Aphids (Grylloprociphilus imbricator) in exchange for honeydew, which the aphids excrete, Southern Appalachians, South Carolina, USA, O...

Doug Wechsler / Beech blight aphid (Grylloprociphilus / Fagiphagus imbricator) on Beech tree, woolly aphids, Pennsylvania, USA

Doug Wechsler / Beech blight aphids (Grylloprociphilus imbricator) colony covering a tree branch, with waxy excretions that protect them from predators, Crossways Preserve, Pennsylvania, USA. July.

Doug Wechsler / Beech blight aphid (Grylloprociphilus imbricator) on tree bark, showing waxy excretion that protects it from predators, Fulshaw Craeg Preserve, Pennsylvania, USA. August.