Alder State of Awareness

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Filed under Outdoor Notes

December 2, 2011

For any of the numerous people who passed by on that country road on Sunday, it would not be an unreasonable question to ask, “Why is that fat man walking around hip-deep in that pond.” There are several possible answers to that question. The short answer would be, to look at aphids.

Wooly Alder Aphids (Prociphilus tessellates)

Wooly Alder Aphids

Herewith, a longer answer.

There are, in fact, aphids, Wooly Alder Aphids (Prociphilus tessellatus). As the name implies, these aphids feed mostly on alders, although there are some references that they move to maple trees late in the fall, perhaps to take advantage of the early and rich maple sap. That movement, I suppose, must be made by winged females, which move to the maples to produce young. Young in aphids can be produced parthenogenically[1] —which is a scientific word that means, basically, without the participation of males.[2]

The pond in question is surrounded by alders (Alnus spp.). Unhappily, I don’t know which type of alder. In fact, until I started doing the research to write this Note, I thought there was only one type of alder in this part of the world. Wrong again.  There are four, Smooth, Black (non-native), Speckled, and Mountain (rare). In order to determine which one, I will have to examine the twigs closely: I will get back to you on that.

Alders produce male and female catkins on the same limbs. The male catkins are usually rust and green. The female produces a cone-like structure that will actually bear the seeds.

Male alder catkin

Male alder catkin

Female alder cones

Female alder cones

These alder cones are subject to a fungus, the Alder Tongue Gall (Taphrina alniI), which produces straplike fruiting bodies that will desiccate and remain on the catkin.[3]

Alder Tongue Gall (Taphrina alni)

Alder Tongue Gall

Taphrina is a large genus of fungi that includes species that are pathogenic on oak, maple, poplar, and—most famously—on peach (Peach Leaf Curl, Taphrina deformans).

But I was here to look for aphids. I had seen aphids in these alders earlier in the summer. The alders that were heavily infested showed yellowing of the leaves.

Aphids suck the sap out of plants. The sap passes through their bodies rather quickly, and the by-product is pumped out of the insects’ anus. The by-product is known as “honey dew”—there’s a euphemism for you.

"Honey Dew" appearing from the anus of an aphid

The "honey dew" is that little shiny bubble center frame.

Honey dew is, apparently, both delicious and nutritious, at least if you’re an ant.

Aphids are not nimble creatures, so they have “hired” the ants as bodyguards, and they pay them with sweetened…butt leakage. Ants actually wander the twigs around the aphid colony waiting for their next meal to pop out of the back end of an aphid. In return for this treasure, the ants provide a modicum of protection against predators.  They are reported to be particularly effective in discouraging ladybugs—ferocious aphid predators.

Ant tending Wooly Alder Aphids

Ant guarding aphids. I have no idea what kind of ant--if anyone does, I would love to hear from you.

However, they are not as effective against another predator, a unique predator, and a quest bug of mine. But that is for my next post. Watch this space.

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[1] The name of the Parthenon in ancient Greece comes from the same root, as the temple was connected to virginity associated with the goddess Athena.

[2] Now where is the fun in that?

[3] I know this because Seabrooke Leckie blogged about it on her marvelous site almost exactly one year ago. She, in turn, got the information from  Willow House Chronicles, which is written by her mother.

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One Response

  1. Love it, especially the breadth in the footnotes.

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