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Blue-winged wasp on goldenrod |
Goldenrods are magnets for a wide variety of animal life. I am
talking about the six-legged and eight-legged fauna, insects and
spiders.
I enjoy leading walks in the fall to observe all the bounty of tiny
wildlife buzzing, zipping along, and crawling and hiding in the
goldenrod patch. I call this program
"The goldenrod zoo".
My favorites are the pollinators; but I also like to point out the
various kinds of galls and their amazing makers and residents.
Goldenrods used to be regarded as weeds in North America; many people
still see them that way. Recently I heard a gardener, an organic
gardener at that, who wants to eliminate them from her property. This
made me think about the beneficial qualities of goldenrods, both to
wildlife in general and to gardens in particular. So I started a list.
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Goldenrod round galls in winter. One of them has been opened by a chickadee |
Round galls are produced in the stems of tall goldenrods by a species
of flies (the goldenrod fly). Gail Eichelberger described the fly’s
life cycle in
"The Gall of That Goldenrod"
in "Beautiful Wildllife Garden." She also mentioned how
the gall fly larvae can serve as food for chickadees and downy
woodpeckers during the winter months. I will simply add that you can
tell which of these two birds has opened each gall. Downies skillfully
chisel a clean hole, while chickadees are sloppier, and destroy a good
part of the gall to get to the prize.
There are a few other types of galls, produced by moths or flies, many of these insects also provide food for birds.
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Sweat bee Agapostemon |
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Sweat bee Augochloropsis |
Let us take a look at the goldenrod flowers visitors. There are at
least 380 species that visit just one species, the Canada goldenrod (
Solidago Canadensis).
Not all of them are pollinators and many visit other flowers besides
goldenrod. But they all benefit from these flowers’ nectar and pollen.
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Syrphid fly, a good aphid control |
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Feather-legged fly, Tachinidae
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Leaf-footed bug. Notice the tachinid fly eggs on its head |
Here I am listing a few whose larvae feed on other insects, so they
provide an important ecosystem service as biological controls. The larvae of some Syrphid flies feed on aphids. Tachinid flies lay their eggs on other insects especially on stink bugs or related bugs which feed on plants.
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Potter wasp |
Wasps of many kinds are very abundant in the fall, so
perhaps they are the most common visitors of goldenrod flowers. They include
not just the more familiar and feared ones, hornets and yellow jackets, but
also many solitary ones, which are less likely to sting. All of them catch
insects or spiders to feed their larvae.
There is one in particular that has become a favorite
of mine, the large and colorful blue-winged wasp, Scolia dubia. It is rather
hairy and heavy-bodied, unlike most wasps. Its wings are supposedly blue, as
the name suggests. But you need a little imagination, or the sunlight hitting
them just right; otherwise they look smoky. The body is very dark blue-black,
except for the last few segments of the abdomen which are reddish or orange with
two bright large yellow spots.
The nice thing about this wasp is that its offspring feeds on the
larvae of June beetles. The females spend a good deal of time searching
the ground for beetle larvae and digging them out; this earns them their
other common name: digger wasp. When a female wasp finds a grub, it
paralyzes it. Then it digs a little deeper, builds a small chamber, and
lays an egg on its victim. Gruesome, yes, but effective.
And here comes the best part: The blue-winged wasp has developed a
taste for Japanese beetles and treats them the same way as June beetles.
We all know that one of the most serious problems with introduced pests
such as this is that they have left most of their enemies behind in the
old country, so they can multiply unchecked. The USDA tried
unsuccessfully to introduce some relatives of this wasp as biocontrols
of the Japanese beetle. So it is wonderful to see that a native insect
has become an enemy of the invasive pest.
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Blue-winged wasp |
Here’s to the blue-winged wasp and to the goldenrods that sustain it in the fall!
First published in "
Native Plants and Wildlife Gardens" as "G
oldenrod, a Weed or a Treasure?"
Beginners Guide to Pollinators and Other Flower Visitors
All photos by Beatriz Moisset. All rights reserved
© Beatriz Moisset. 2013