Woolly aphids on autumn alder trees
The temperatures of the last several months have consistently been around normal. Meanwhile, nearly all have been quite a bit above normal in precipitation. The result was wet and warm and plant life responded with good growths of wildflowers, fr...
The temperatures of the last several months have consistently been around normal. Meanwhile, nearly all have been quite a bit above normal in precipitation. The result was wet and warm and plant life responded with good growths of wildflowers, fruits, berries and thick gardens. These conditions lingered into late summer and the woods kept the lush growth of ferns that were followed by a plethora of mushrooms. These fungi show up every year at about this time, even if the year is dry. But with the wet conditions that we had, the fungi thrived.
Walking in the woods a month ago could often garner 15-20 kinds of mushrooms. And not only was there diversity, there was a large number of each kind. Yellow Amanitas blended with the red Russulas and Hygrophorus, the yellow-gold Chantherelles, the white Agaricus and the brown Marasmius. Each walk was a fungal fascination.
But that began to change as we got further into the cooling month of September. After so many months of above-normal precipitation - only January and July were not beyond the usual for this year - September was not only drier than normal, the total was far below. As a result, walks during the second half of the month and the days leading up to early October revealed fewer fungi.
I still see growths of some late ones. Entoloma, Armillaria, Coprinus and Pholiota, along with several colonies of puffballs during a recent walk, showed me fungi were still with us, but not like earlier. And then I saw something that looked a lot like a fungus growth on a tree.
At several sites, all being on alder trees and all being in damp places, I noticed what appeared to be thick growths of white hairs standing up from the bark of these small trees. Upon closer look, I saw that they were not at all growths of fungi, but colonies of insects. These were the strange white aphids known as woolly aphids, or woolly alder aphids.
Woolly aphids get their name from the white strands that stick out from their bodies, giving the appearance of furry hair as we might see on a moldy fungus growth. Woolly aphids are not the only non-fungus to be incorrectly labeled as one. Many lichens are called fungi. A wildflower that has no chlorophyll, the Indian pipe, is often confused for a type of fungus. Woolly aphids are insects and much different from fungi, but with this apparel, they can certainly get confused.
The white "woolly" material is actually long strands of a waxy secretion that grows out from and through the exoskeleton of the aphids' bodies. Such unique attire discourages predators from attacking them and helps insulate the colony as we now move into fall. Woolly aphids are present somewhat throughout the summer, but I always find them the most in fall and always on alder trees. Now as the leaves dry and drop off, these white colonies become even more apparent. Probably the easiest time to see woolly aphid colonies is now in October, after the leaf cover is gone.
Aphids are a large group of very small insects. They are highly variable and can range in colors from these white ones to yellow, purple, green and even black. Typically, aphids need to be in colonies to survive. They live in groups, often numbering in the hundreds. Nearly all are wingless females. In late summer, some winged males and females will show up. On the plant stems where they live, they penetrate into the veins of the plant to feed on the sap, regardless of the plant being woody or non-woody.
For much of the season the colony is only females, but that does not stop them from reproducing. As an interesting interspecies means of surviving, aphids have formed a "friendly" relationship, or mutualism, with ants. The aphids exude a sweet sticky substance as a waste product known as honeydew. Ants are particularly fond of this material and will herd and guard the aphid colonies so they are able to get their sweets satisfied. It seems like any group of aphids seen on a stem of a plant will have ants here, too.
Such was the case with the woolly aphids as well. Though they look different from the normal aphids, the ants still want to be with them. And each colony of these white insects that I saw during my walks had ants, in some cases many ants, nearby.
We'll continue to see these strange colonies on the alders until the weather gets too cold. I have seen them when snow was on the ground. Eventually they drop off when it gets too chilly.
Retired teacher Larry Weber is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” Contact him c/o firstname.lastname@example.org .