10.16.11 We've been learning about and looking for Woolly Hemlock Adelgids for a couple years because their alien origin leaves them in our environment without natural predators, thus they're free to multiply and spread and cause the eventual death of Hemlock trees. The Woolly Alder Aphid pictured here feeds, reproduces, and multiplies in much the same way as the Woolly Hemlock Adelgid; however, it doesn't get out of control because it has native predators that keep it in check. Like many other aphids, this aphid is tended by ants which benefit from the "honeydew" that they produce. The sap the aphids suck from the host is primarily sugars; to get enough protein for reproduction, the aphid consumes more sugar than they need, and honeydew is produced to get rid of this excess. The honeydew is what causes the black, sooty deposit on surfaces below the aphids.