Today's Ramble was led by Dale Hoyt.
Here's
the link to Don's Facebook album for today's Ramble. (All the
photos in this post, except when otherwise credited, are compliments of Don.)
Today's post was written by Dale Hoyt.
28 Ramblers met today.
Today's reading: Richard read The
Summer Day by Mary Oliver.
Dale read the June 29th entry from Donald
Culross Peattie’s An Almanac for Moderns:
THE merest beginning upon a
little specializing in the
swallows led me to the sandbank, to the burrowing
bees and their beetle guests, and has sent my thoughts straying upon the
biology of the social habit, to which life in a cliff seems to give rise. After
all, our own ancestors, were cliff dwellers. From there I have strayed in my
musings to the nature of parasitism, as it is exhibited by the Hornia beetles,
as well as, I learn, several other members of the same family. One may object
that all this is reprehensibly diffuse. I should concentrate upon swallows, and
not leave them for blister beetles until I know all about the birds.
But the purpose of studying
Nature at all, aside from the distraction which it affords, (and it is in the
nature of distraction not to dwell on anything to the point of tedium) is that
the study should illuminate the relation of living things to each other, to us,
to the environment. One thing should lead to something quite other. Complexity
is the keynote of biology-a fact which those who have been trained first in the
exact or physical sciences can never seem to grasp. The goal of biological
thought is ramification, many-viewpointedness, and a man who drops his swallows
uncompleted because he has suddenly grown excited over beetles is simply a man
who is growing.
Show and Tell:
- Richard brought a bundle of dried heath asters he found riverside, apparently cut at ground level by a beaver or muskrat, wondering if anyone had an idea about what might have cut them down and for what purpose. The day after he had found this single bundle, the entire patch had been cut and removed. Based on the location, he really doesn't think it was human activity that was responsible. Most of the cuts were on an a near identical angle.
- Gary brought a limb tip from a tree and wanted an opinion, thinking it was an invasive plant. Linda identified it as Carolina Buckthorn, native to the Southeast U. S. Piedmont. (It is found along the White Trail at the road crossing from the Dunson garden over to the ROW).
Today's
Route: We walked through the Shade Garden to the
Dunson Native Flora Garden. From there
we left the Dunson garden through one of the deer fence openings and walked
past the Passionflower vines and down towards the floodplain section of the
ROW. We returned by taking the White
Trail spur up from the ROW to the Callaway Administration building back to the
Visitor Center.
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| Cicada Killer wasp |
Cicada Killer
wasps swarm about near the beds between the lower steps and the fountain. These
are the largest wasps native to North America, exceeded in size only by the
European Hornet, an introduced species.
Several Ramblers noticed wasps
apparently “fighting,” grappling each other. These are probably males engaged
in a territorial dispute. The territory is the soil in the bed – it is the nesting
site used by the female wasps.
The female Cicada Killer is
a solitary wasp, meaning that she is reproductively independent of others of
her kind. She digs a tunnel in suitable soil, excavating several side chambers
and then goes in search of her prey, cicadas. When she finds one she pounces on
it, stinging it. The sting paralyzes the cicada and she carries it back to her
nest. If the wasp is large and the cicada small she can actually fly it back to
the nest, but larger prey are dragged on the ground. (If you think about it,
this is a mystery. How does the wasp know where the nest is located? If it
scouts out the territory while flying how can it translate that knowledge to
the ground, when it is dragging a cicada home?)
At the nest the wasp
carries the cicada into one of the chambers, lays an egg on it and seals the
chamber. When the egg hatches the larva eats the still living, but immobile,
cicada. When it finishes its meal it pupates and remains in its underground
chamber until the following July or August, when it emerges.
By the way: in spite of
the Cicada Killer’s fearsome appearance it’s sting is relatively mild, less
painful than a honeybee’s.
 | |
| Witchhazel Conical Gall |
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| Witchhazel Conical Gall opening on undersurface of leaf |
After the first hairpin bend in the Shade Garden sidewalk
there are two species of Witchhazel, Ozark
Witchhazel and Eastern Witchhazel.
These plants are best known for their medicinal uses as an astringent. They are
also unusual in that they flower in late autumn, early winter, after most other
plants have ceased blossoming.
Our interest is in the dark, conical structures found on
the leaves of the Eastern species. These are called galls – an abnormal growth
on a plant tissue. These galls resemble a witches hat and are caused by an
aphid that lives and feed inside the gall. Each gall is started by a single aphid
that reproduces asexually inside the hollow gall. In the spring you would find
dozens of tiny aphids inside each of galls. Later in the year winged aphids of
both sexes are produced and these emerge from a hole in the bottom of the gall.
They mate and fly to an alternate host tree, the River Birch. There they
produce another generation of asexual, wingless aphids. Eventually these
produced a winged, sexual generation that flies back to the Witchhazel and
begins the cycle again.
If you examine the leaves of the Ozark species, which is
not native to this area, you will be hard pressed to find any of these galls.
Apparently our native Witchhazel aphids don’t recognize it as suitable food.
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| Possible spider egg sac |
Spider Egg Sac?
While Susie was searching for galls on the Ozark Witchhazel she discovered a
cluster of leaves held tightly together by silken threads. This is commonly how
spiders protect their eggs. The weave a tight, silken bag that holds the eggs
and is securely fastened to a group of leaves by more silken strands. I didn’t
want to confirm this by tearing open the sac because that would have injured or
destroyed the eggs, so I don’ know for sure that it was produced by a spider.
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| Loblolly pine cones; the upper, green cone developed last year; the brown cones developed two years ago. |
Loblolly Pine
cones
Tuesday’s storms knocked down a lot of branches,
including a Loblolly pine branch with two sets of cones, one pair green and,
below them, some brown cones. It takes a little more than two years for a Loblolly
to produce mature cones, so the different colors we see today are two different
generations of cones. The green ones would be mature next fall and released
their seed in October, 2019. The brown cones would release seeds this fall.
Some Ramblers were aware of pines that require fire in
order to release seed from their cones. This type of pine cone is termed “serotinous,”
and is found in pine trees that are adapted to fire. In peninsular Florida the
Sand Pine, Pinus clausa, retains unopened cones for many years until a fire sweeps
through the area. The heat melts the resin that holds the cone closed and the
scales curl open, releasing the seeds. The fire has killed competing vegetation
below and provided a nutritious bed of ashes for the seeds to germinate in.
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| Black Cohosh in bloom three weeks ago |
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| Black Cohosh developing fruits |
In the Dunson Garden Black
Cohosh ceased flowering about two weeks ago. It is now setting fruit.
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| A large, female Jack-in-the-Pulpit |
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| The fruits of the Jack-in-the-Pulpit above. The withered structure directly below the green fruits is the remains of the "Pulpit" that surrounded the spadix that carries the developing fruits. |
Jack in the Pulpit
Look here for the interesting
sex life of Jack in the Pulpit.
 |
| A leaf mine in the leaf of Golden Ragwort. Note the increase in width starting at the lower left. The sudden increase in width is when the larva experience its first molt and increased in size. |
Leaf miners
are insects whose larval stage feeds on the thin layer of tissue between the
upper and lower epidermis of a leaf. Most of the leaf miners are either fly
larvae or moth larvae. They are little studied and, consequently, difficult to
identify. We regularly find leaf mines in Golden Ragwort and Columbine, but
they can be found in many other plants if you know what to look for.
As the larva feeds its head swings from left to right.
Younger larvae are small, so the trail of eaten food is narrow, but as they
grow in size they leave a broader path. You can trace the growth of the larva
if you start at the narrowest point of the leaf mine and follow it as it
wanders through the leaf. It will end where the larva pupates, either inside
the leaf or where it drops out of the leaf to pupate in the ground.
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| Developing fruit of the Purple Passionflower. |
Purple
Passionflower vines are growing over the deer fence at the bottom of the
Dunson Garden. We have stopped here the last few weeks to look for caterpillars
of the Gulf Fritillary butterfly. Two weeks ago one small caterpillar was
spotted, but we were unsuccessful today. The vine has set many green fruits about
the size of 1 ½ to 2 golf balls. They will ripen later in the summer, turning
yellow and wrinkled. Our native species (Passiflora
incarnata) is related to a commercially grown species, Edible Passionflower
(P. edulis) which is widely grown in
tropical climates and used for flavoring soft drinks and ice cream.
The Gulf Fritillary butterfly cannot survive our winters
in any of its life stages (egg, caterpillar, pupa or adult). As a result we
have to wait for immigrant butterflies from milder climates, like peninsular
Florida, to fly north. It takes them a while to reach south Georgia and some of
their offspring from there eventually make there way up here. By the end of
summer these vines will have been decimated by hundreds of caterpillars.
 | |
| Carpenter Bee nectar robbing on Scarlet Beebalm Note the smooth, bristleless abdomen. |
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| Bumblebee nectar robbing Scarlet Beebalm Note the fuzzy abdomen in contrast to the bristleless abdomen of the Carpenter Bee. |
The bed of Scarlet
Beebalm at the bottom of the Dunson Garden attracted a lot of Carpenter Bees this morning. Usually
when people see bees visiting flowers their knee-jerk reaction is to say, “Look,
they’re pollinating the flower.” A careful look at the Carpenter Bees shows
that they are thieves. Instead of entering the opening of the flower, which
would require them to pick up and deposit pollen in order to reach the nectar
at the base of the flower, they just bite a slit in the base and suck up the
nectar there. Not everyone who visits a store is a customer; some are shoplifters.
Some of our beloved honeybees visit the flowers that the
Carpenter Bees have cut open. They are happy to make use of the opening made by
the Carpenter Bees. Since they didn’t break in themselves maybe we should
consider them “nectar looters,” rather than “nectar robbers.”
Surprisingly enough, where it has been studied, nectar
robbery does not seem to affect the amount of seed produced by the plant. The
reason for this is presently unknown.
Silvery
Checkerspot butterfly.
Not many butterflies were flying today, but the one I caught
I misidentified. I called it a Pearl Crescent in the field, but looking at Don’s
photographs it is clearly not a Pearl Crescent (PC); it's a Silvery Checkerspot (SC).
Identifying these two species depends on looking for some subtle patterns.
PC:
Identifying these two species depends on looking for some subtle patterns.
PC:
- Slightly smaller
- Row of black dots on upper surface of hind wing always solid.
- Black tip of fore wing without orange dots.
- Slightly larger
- In the row of black dots on the upper surface of the hind wing at least one will have white or orange center.
- Black tip of fore wings usually with 3 orange spots.
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| Silvery Checkerspot upper surface (Wing tip wear obscures one of the distinguishing features) |
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| Silvery Checkerspot lower surface |
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| Pearl Crescent upper surface By Andy Reago & Chrissy
McClarren (Pearl Crescent - butterfly) [CC BY 2.0
(https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons |
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| Silvery Checkerspot upper surface By Judy Gallagher [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons |
If you study these photographs carefully you can also find other ways in which the two species differ. These may well be reliable characteristics, but you can only tell by examining a large number of different individuals to see if they are truly diagnostic. The PC, in particular, can be highly variable, so much so that some lepidopterists think it is composed of several species. Others think it is simply one species that is seasonally and geographically variable.
Butterfly Color Patterns
The beautiful markings on the upper and lower surfaces of butterfly wings are like pointillist paintings. Both surfaces are covered with microscopic scales, arranged like shingles on a roof. Each scale is a single color. The pattern is formed by the distribution of these scales. In areas of uniform color all the scales are a single color. Areas with complex patterns have an ordered arrangement of different colored scales.
The species specific patterns allow butterflies to recognize their own species. In many species the sexes have different patterns, allowing potential mate recognition.
The scales are attached to the wing membrane at a single point and are easily removed. Just the act of flapping the wings causes scale loss. As a result, the older butterflies usually have fainter, "worn" appearences.
Because the wing scales are so easily removed butterflies and moths can sometimes escape from sticky spider webs, leaving behind just a few hundred scales.
Butterfly Color Patterns
The beautiful markings on the upper and lower surfaces of butterfly wings are like pointillist paintings. Both surfaces are covered with microscopic scales, arranged like shingles on a roof. Each scale is a single color. The pattern is formed by the distribution of these scales. In areas of uniform color all the scales are a single color. Areas with complex patterns have an ordered arrangement of different colored scales.
The species specific patterns allow butterflies to recognize their own species. In many species the sexes have different patterns, allowing potential mate recognition.
The scales are attached to the wing membrane at a single point and are easily removed. Just the act of flapping the wings causes scale loss. As a result, the older butterflies usually have fainter, "worn" appearences.
Because the wing scales are so easily removed butterflies and moths can sometimes escape from sticky spider webs, leaving behind just a few hundred scales.
 |
| young Golden Garden spider |
Golden Garden
spider
Among the wingstems we found a tiny Golden Garden spider
on her tiny web. The zig-zag white silk pattern, a so-called “web decoration,”
is called a stabilimentum and its function is debated. One reasonable hypothesis
is that it makes the web obvious to birds, preventing they from flying into it.
The web decoration of a Barn spider was the inspiration
for Charlotte, in the book, Charlotte’s Web. The author, E. B. White, was reportedly
inspired by the web decorations of a Barn spider to make Charlotte literate. Wikipedia
says that Charlotte A. Cavatica is Charlotte’s full name. “A. Cavatica” is a
reference to the scientific name of the Barn spider, Araneus cavaticus. The
only problem with this interpretation is that one source (Behavioral Ecology,
Volume 19, Issue 4, 1 July 2008, Pages 799–804, https://doi.org/10.1093/beheco/arn030)
states that the Barn spider does not decorate its web. It seems possible to me
that White mis-identified the spider. But that doesn’t detract from the charm
of the book.
Many times Ramblers have asked,”Why don’t I see spiders
until the fall?” The small size of this Garden spider is a clue. Many spiders die
after laying their eggs in the fall. Those eggs hatch the following spring and
the baby spiders are very tiny. It takes them most of spring and summer to grow
to the size where their webs become noticeable. They are there all the time, we
just don’t notice them.
SUMMARY
OF OBSERVED SPECIES:
Cicada Killer Wasp
|
Sphecius
speciosus
|
Red Wiggler worm
|
Eisenia
foetida
|
American Witchhazel
|
Hamamelis
virginiana
|
Ozark Witchazel
|
Hamamelis
vernalis
|
Loblolly Pine
|
Pinus taeda
|
Black Cohosh
|
Actaea racemosa
(=Cimicifuga racemosa
|
Triangulate Orbweaver
|
Verrucosa arenata
|
Jack-in-the-Pulpit
|
Arisaema
triphyllum
|
Golden Ragwort
|
Packera aurea
|
Leaf Miner
|
????
|
Mockernut Hickory
|
Carya tomentosa
|
Purple Passionflower
|
Passiflora
incarnata
|
Flea beetle
|
Chrysomelidae: Disonycha
sp.
|
Assassin bug
|
Family Reduviidae
|
Shield Bug
|
Order Hemiptera
|
Scarlet Beebalm
|
Monarda didyma
|
American Sycamore
|
Platanus
occidentalis
|
Carpenter Bee
|
Xylocopa virginica
|
Bumblebee
|
Bombus sp.
|
Silvery Checkerspot butterfly
|
Chlosyne nycteis
|
Two-lined Spittlebug
|
Prosapia bicincta
|
Weevil
|
Order Coleoptera
|
Treehopper
|
Acanalonia conica
|
Long-legged Fly
|
Family Dolichopodidae
|
Golden Garden Spider
|
Argiope aurantia
|
American Spadefoot Toad
|
Scaphiopus holbrookii
|
Tall Thistle
|
Cirsium
altissimum
|
Oak Apple Gall
|
Order Hymenoptera
|
Coral Slime mold
|
Ceratiomyxa
fruticulosa
|
