Today's Ramble was led by Dale Hoyt.
The photos in this post, except where
noted, came from Don's Facebook album (here's the link).
Today's post was written by Dale Hoyt
and Linda Chafin.
24 Ramblers met today.
Announcements:
The Johnstone
lecture at the Botanical Garden is rescheduled to 7:00 p.m., Sept. 26:
Backyard Bugs
Tuesday, Sept. 26, 7 p.m. (talk, reception and book
signing)
Jaret C. Daniels, Ph.D., author
of Backyard Bugs: An Identification Guide to Common Insects, Spiders, and More,
Associate Professor of Entomology at the University of Florida and the Director
of the Florida Museum of Natural History’s McGuire Center for Lepidoptera and
Biodiversity. Free but to help us
prepare for the reception, please register here
or call 706-542-6138 by Sept. 25.
The Johnstone Lecture, sponsored by
FRIENDS of the State Botanical Garden of Georgia, was named in honor of the
State Botanical Garden’s first director, Dr. Francis E. Johnstone,
Jr.
Today's reading:
Catherine
read Running Egret from Naomi Shihab
Nye's collection of poems: Honeybee
(2008, Harper Collins). (You can find the text of the poem at this website.)
Dale read
a poem recommended by Bob Ambrose. Bob is recovering from a serious health
problem and we hope he will be able to rejoin us soon on our rambles. The poem is
Fungus on Fallen Alder at Lookout Creek
by Ellen Bass. You can find the text and listen to the author read her poem at this link.
Today's Route:
Through the Dunson Garden via the mulched path to the road, along the
road to the area where the Passion Vines are planted, then to the power line
and toward the river. We then returned to the Visitor Center and Cafe Botanica
for refreshments and conversation.
Gulf Fritillaries
. . . Several weeks ago (August 17) we
visited the Passion Vines growing on the deer fence next to the road at the
bottom of the Dunson Native Flora Garden. Then we saw eggs and caterpillars of
the Gulf Fritillary butterfly. Today we found nearly all the Passion Vine
leaves consumed, dozens of Gulf Fritillary caterpillars of various sizes and
three or four Gulf Fritillary chrysalids.
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| Gulf Fritillary egg on Passionflower tendril |
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| Gulf Fritillary caterpillar |
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| Gulf Fritillary chrysalis |
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| Gulf Fritillary butterfly on Thistle |
. . . and Insect
metamorphosis . . . Insects can be roughly divided into two groups: those
that have complete metamorphosis and those that don't. Those that have complete
metamorphosis have four distinct stages in their life cycles: egg, larva, pupa,
adult. The larval stage hatches from the egg and begins feeding. As it grows it
sheds its "skin," really its exoskeleton, several times, increasing
in size after each molt. In the last molt the pupa emerges, instead of another
caterpillar. The pupa is immobile and usually attached to some object or buried
in the soil. Finally, the adult form emerges from the pupa. None of these stages
of development look alike. In butterflies and moths the larval stage is called
a caterpillar and generally looks like a worm with legs. The butterfly pupal
stage in some species is a beautifully ornamented capsule with gold or silver
decorations; in other species it resembles a partially eaten dead leaf. The
pupal stage in butterflies is called a chrysalis (or chrysalid). The chrysalis
is immobile, but inside it enormous changes are taking place. Most of the
tissues of the caterpillar are self-destructing, with the exception of the
nervous system and a group of embryonic tissues that have remained dormant, up
to this point, inside the caterpillar. These embryonic tissues now begin to
grow, feeding on the substances from the self-destructed tissues of the larva.
They develop into the adult insect that emerges from the pupa.
| |
| Gulf Fritillary chrysalid; eye at bottom; wing is swelling on left |
If you look closely at the Gulf Fritillary chrysalis you can
see the outlines of some of the adult butterfly's structure. The chrysalis
hangs by the tip of the abdomen, so it's, in effect, upside down. The swellings
at the other end are the developing eyes and just above (behind) them you can
see where the wings are. When development is complete the skin of the chrysalis
splits open and the butterfly drops out, being careful to hang on to the
chrysalis shell with its legs. The wings will appear as wrinkled sacks and the
butterfly pumps its body fluid into the wings to inflate them to the proper
size. It takes a while for wings and the rest of the exoskeleton to harden and
the butterfly hangs there until it is able to fly.
In moths the pupal stage is usually brown and not as
colorfully decorated as in butterflies. Also, in many moths the pupa is
surrounded by a layer of silk that protects it. This is called the cocoon, a
term that can mean just the silk jacket or the combination of the pupa plus the
silken enclosure.
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| Purple Passionflower |
. . . and Passionflowers.
There were lots of questions about the edibility of the passionflower fruit.
The common Passion Fruit (Passiflora
edulis), a native of South America, is grown around the world for its
highly sought after fruits (the scientific name “edulis” means edible.) It is used to flavor desserts, yogurt, mixed
drinks, and juice mixtures. Our Passionflower species (Passiflora incarnata), also known as Maypop, is edible too, with a
tart-sweet juice contained in the sacs (technically, arils) that surround each
of the black seeds. The yellower the fruit, the sweeter the juice. The rind and
the seeds can be bitter. Passionflower leaves are included in herbal tea mixes
that aim to promote sleep and calm–an odd effect for something called “passion
flower”! (The passion in the name refers to the Passion of Christ, not a state
of romantic ecstasy. In their efforts to convert the native people of Brazil to
Christianity early Jesuit missionaries made up symbolic biblical references for
the flower parts; e.g., the ten sepals and petals represented the 10 faithful
disciples, the three styles the three nails, etc.)
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| Margined Blister Beetle |
As we did last summer at about this time, we discovered a
Margined Blister Beetle. Blister
Beetle blood contains a caustic chemical called cantharidin. When
they are roughly handled they release blood from their leg joints and contact
with the fluid will cause blisters to develop on the skin. If ingested,
cantharadin produces an effect similar to Viagra on men, but with additional very
unpleasant side effects. The late, great biologist Thomas Eisner, in his book For the Love of Insects, tells the story
of a French physician, J. Meynier, stationed with a military garrison in
Algeria in 1869. A large number of soldiers sought his help, all suffering from
the same symptoms: "abdominal pain, dryness of mouth, pronounced thirst,
frequent and painful urination, general weakness, depressed pulse rate, reduced
arterial pressure, lowered body temperature, nausea and anxiety,"
accompanied by painful and prolonged Viagra-like effects. Dr. Meynier
discovered that all the men had feasted on frog legs they had collected locally
the night before. He then went to the nearby swamp and discovered that the
frogs had been eating large quantities of blister beetles that were extremely
abundant there. Dr. Meynier, as well as other physicians of the time, knew of
cantharidin and that it was found in Spanish fly, which is the finely ground
bodies of dried Blister beetles. The frogs had eaten the blister beetles and
absorbed cantharidin in their tissues and the poison was passed on to the men
who had eaten frog legs.
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| Disturbed Fire ant nest with brood (larvae, pupae) near surface |
Fire Ants were
accidentally introduced to the United States around 1940 through the port of
Mobile, Alabama. They are native to Brazil and Argentinea and live in open
habitats that are subject to periodic flooding. In the Garden we find their
nests in a similar location: the power line right of way, especially in the
flood plain. Several of us accidentally walked over their nests this morning
and this gave us a chance to see some interesting aspects of their behavior.
The disturbed nests were swarming with ants carrying larvae and pupae. Why were
these so close to the surface? It's a matter of thermoregulation. Ants, being
cold blooded, take on the temperature of their nest. The nest can be as much as
six feet deep. Soil temperatures are most variable at the surface but become
more stable the deeper you go. They are also cooler at depth than the surface
in the summer and just the reverse during winter. On a sunny fall day the soil warms
up and the ants bring the developing brood up near the surface. When they are
warmer they develop faster and take less time to metamorphose into workers,
providing a larger work force to gather food for the colony. The mystery is how
the workers know when to bring the brood up to the surface. Ant colonies don't have
bosses that assign tasks – each ant is thought to respond individually to largely
unknown signals. And yet, the appearance of coordinated activity emerges
without apparent organization. Truly a mystery!
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| Southern Flannel Moth (?) caterpillar |
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| Long-tail Skipper caterpillar |
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| Saddleback caterpillar |
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| Great Leopard Moth caterpillar |
More caterpillars. As we move into
Fall the last generation of caterpillars reaches a size where they become more
conspicuous. Some species will overwinter as caterpillars, producing an antifreeze
in their body fluids to survive the low winter temperatures. Other kinds
overwinter as pupae that also have antifreeze protection. A few kinds can
overwinter as adults, e.g., the Mourning Cloak and the Anglewing butterflies. These
species are adapted to a temperate climate with a very cold season. But some of
our butterfly species are annual immigrants from warmer, more southern locales
and lack the adaptation to winter temperatures. Local examples are the Gulf
Fritillary, Cloudless Sulfur and Long-tail Skipper. The adults we see in our
area early in the summer are immigrants from the south. They may produce one or,
at most, two generations before they either die or migrate back to more
southern climes. The chrysalids they produce late in the season cannot survive
our winters, but as the climate warms they may do so. Then the problem will be
finding host plants that might not be available in the early spring.
Caterpillars are large enough to
attract attention at this time of year and we found, besides the Gulf
Fritillary, five more interesting ones: a skipper, two Tiger Moth caterpillars,
a Flannel Moth and a Slug Moth.
The Slug Moth we saw previously, it's
a Saddleback Caterpillar and it can
deliver a painful sting if you contact the bristles.
The Flannel Moth caterpillar is unusual looking and dangerous. Several
people who have touched it have experienced pain and been rendered unconscious.
Plus, you may notice that resembles a prominent politician's hair!
The Tiger moth caterpillars are the Fall Webworm, which we have seen before, and a new find, the Great Leopard Moth caterpillar, which
is an all-black wooly bear.
The caterpillar of the Long-tail Skipper was feeding on a Sand
Bean vine and has a large head that is typical of skipper caterpillars. This species
is only a temporary resident here in the piedmont because no stage in its life
history is capable of surviving through our winters. These butterflies appear
in late summer, migrants from further south. In favorable years they may be
seen as far north as New York.. A warming climate may change all that.
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| Wheel bug (mouthparts are below head & pointing backward) |
Assassin bugs are predators.
They come in a variety of sizes and one of the largest is the Wheel Bug, named for the shape of the
first thorax segment that looks like half a tractor wheel. It hangs out on
vegetation and flowers and grabs any insect that comes within reach, stabbing
it with its piercing, sucking mouthparts. It injects a mixture of digestive
enzymes that begin liquefying the flesh of its victim and then sucks up the
soup. It will attack and kill insects larger than itself. All the members of
the Order Hemiptera have this type of mouth part, but the majority use it to
suck plant juices. Predation on insects and other kinds of animals has evolved
independently several times in the hemiptera.
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| Katydid on Passionvine fruit |
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| Short-winged Meadow Katydid |
Katydids are like
grasshoppers with antennae that have gone wild. Like grasshoppers, their hind
legs are modified for jumping. Unlike grasshoppers, their antennae are longer
than their body and, in some cases, much longer. Also unlike grasshoppers, they
are very musical – one of the commonest species you probably hear starting to
sing after dusk. The chorus consists of a number of individual males, each of
which is saying something like: "zzzit, zzzit,zzit", endlessly
repeated. Other species have much higher pitched calls that those with aged
ears probably cannot hear. The songs are produced by rubbing a special area of
the forewings together. One of the wings has a series of ridges, called the
file, while the other wing has a single projection, called the scraper. By
moving the scraper across the file a sound is produced. It's like the music
produced by Washboard Willie.
The first Katydid we saw was sitting
on a Passionvine fruit. These insects are hard to identify from just photographs,
so I'm just going to leave the ID of this one at Katydid. (Identifying species
requires having the insect in hand so you can examine detailed structures.) The
other two were found in the thick stands of wingstems and goldenrod and I'm
fairly certain they are Short-winged Meadow Katydids.
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| Yellow Garden spider behind stabilimentum of orb web |
Spiders. We found a Yellow Garden Spider on its web. (It
seems that every book you consult has a different name for this species: Black
& Yellow Garden Spider, Black & Yellow Argiope, Golden Garden Spider
are a few of the names I've found, but all of them are referring to Argiope aurantia.) A prominent part of
the web is the zig zag silken figure where the spider sits. It's called the
stabilimentum, after an early idea that it gave stability to the web. This
conjecture was never really tested, just assumed. But another hypothesis has
been tested. The stabilimentum reflects UV light and birds can see UV light (humans
can't see UV). So it might be that the structure makes the web more apparent to
birds, enabling them to avoid flying into the web and destroying it. How would
this benefit the spider? Silk is a protein and is made at the expense of
protein that a spider could use for growth and reproduction, to say nothing of the
prey it could miss capturing if the web were to be destroyed by a blundering
bird. To test this idea researchers removed spiders that normally don't produce
stabilimenta from their webs. Then they attached pieces of paper mimicking
stabilimenta to half the vacant webs and left the other half unadorned. They
checked all the webs at two hour intervals, recording the amount of damage and
found that webs with artificial stabilimenta sustained much less damage than
the plain webs did. This certainly is consistent with the idea that the
stabilimentum keeps birds from accidentally blundering into the web.
Plants
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| Nodding Ladies' Tresses orchid |
A single Nodding
Ladies’ Tresses orchid was seen growing in the path near the exit onto the
road. Nodding Ladies’ Tresses is one of only five ladies’ tresses to occur in
the Georgia Piedmont. (There are 15 in the state overall, most occurring in the
Coastal Plain). Although ladies’ tresses in general are usually hard to
identify to species, you can narrow it down by flowering time and flower color.
If it’s late summer through fall and the flowers are a pure, bright white
without any color in the throat, it’s very likely to be Nodding Ladies’
Tresses.
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| Ragweed pollen grain enlarged 3700 times (CC Marie Majaura Wikimedia Commons) |
Ragweed is
coming into flower now, much to the chagrin of the 10-30% of Americans who are
allergic to its pollen. Unlike late summer wildflowers with colorful flowers,
such as goldenrods and sunflowers, ragweed’s flowers are small, green, and
inconspicuous. Its pollen is wind-dispersed so it has no reason to invest in
showy, insect-attracting flowers. Although the surface of ragweed pollen is
covered with nasty looking spines, the allergic reaction is actually caused by
proteins coating the pollen grains, not by mechanical irritation. Bad news!
Recent research suggests that the amount of ragweed pollen may significantly
increase “under the present scenarios of global warming.” [Production of
allergenic pollen by ragweed (Ambrosia
artemisiifolia L.) is increased in CO2-enriched atmospheres. Peter Wayne,
PhD; Susannah Foster, BS; John Connolly, PhD; Fakhri Bazzaz, PhD; and Paul
Epstein, MD, Annals of Allergy, Asthma and Immunology 2002;8:279-282.
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| Wingstem; note alternate leaf arrangement |
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| Southern Crownbeard; not opposite leaf arrangement |
Two of our three “wingstems”
(all in the genus Verbesina) have
yellow flowers: Common Wingstem,
with alternate leaves, and Southern
Crownbeard, with opposite leaves. The third Verbesina at the Garden is Frostweed.
It also has winged stems and alternate leaves, but its flowers are white. It
extrudes frozen sap through its stems in late fall and early winter when
morning temperatures are low. The frozen sap takes the shape of ribbons,
flowers, or curls. Wingstems pose a management issue at the Garden: they are native and they support the
caterpillars of the Silvery Checkerspot butterfly. But they are also aggressive
“thug plants,” especially the two yellow-flowered species. They quickly
overwhelm other desirable natives, such as Maryland Senna which seems to have
lost ground to the wingstems and nearly disappeared from the floodplain. To
spray or not to spray? [A check of previous Ramble Reports reveals that Maryland
Senna appeared in its present position in 2014, being absent in the three prior
years.]
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| Tall Ironweed |
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| Late-flowering Thoroughwort |
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| Rabbit Tobacco |
Tall Ironweed
is in full glory now. Some of the plants are as high as 10 feet, crowned by the
large, brilliantly reddish-purple inflorescences. Several other fall-blooming
wildflowers and grasses are now blooming, including Rough-leaved Sunflower, Yellow
Indian-grass, Late-Flowering Thoroughwort with its fuzzy, bright white flower
heads; Camphorweed, with strong cat-litter-box smells and pinkish-mauve
inflorescences; and Tall Goldenrod, which may outstrip even the wingstems in
thuggish behavior.
SUMMARY OF
OBSERVED SPECIES:
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Flowering Plants
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Nodding Ladies Tresses
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Spiranthes cernua
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Purple Passion-flower
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Passiflora incarnata
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Heliotrope
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Heliotropium amplexicaule
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Rabbit Tobacco
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Pseudognaphlium obtusifolium
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Brazillian Vervain
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Verbena brasiliensis
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Camphorweed
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Pluchea camphorata
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Common Evening-primrose
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Oenothera biennis
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Rough-leaf Sunflower
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Helianthus strumosus
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Wingstem
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Verbesina alternifolia
|
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Yellow Crownbeard
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Verbesina occidentalis
|
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Frostweed
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Verbesina virginica
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Common Ragweed
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Ambrosia artemisifolia
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Tall Ironweed
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Vernonia altissima
|
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Sand Bean
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Strophostyles helvola
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Tall Thistle
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Cirsium altissimum
|
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Dotted Smartweed
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Persicaria punctatum
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Late-flowering Thoroughwort
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Eupatorium serotinum
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Tall Goldenrod
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Solidago altissima
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Vertebrates
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Carolina Anole
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Anolis carolinensis
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Insects
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Orthoptera –
Grasshoppers, Katydids, Crickets
|
|
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Orthoptera:
Family Tettigoniidae; Katydids
|
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Short-winged Meadow Katydid
|
Conocephalus brevipennis
|
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Katydid
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Family Tettigoniidae
|
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Lepidoptera –
Butterflies & Moths
|
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Lepidoptera:
Family Nymphalidae, Subfamily Heliconiinae
|
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Gulf fritillary
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Agraulis vanillae
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Lepidoptera:
Family Nymphalidae, Subfamily Nymphalinae
|
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Silvery Checkerspot
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Chlosyne nycteis
|
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Lepidoptera:
Family Megalopygidae; Flannel Moths
|
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Southern Flannel Moth?
|
Megalopyge
opercularis
|
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Lepidoptera:
Family Limacodidae; Slug Moths
|
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Saddleback caterpillar
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Acharia stimulea
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Lepidoptera:
Family Erebidae, Subfamily Arctiinae; Tiger Moths
|
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Giant Leopard Moth?
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Hypercompe
scribonia
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Fall webworm
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Hyphantria cunea
|
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Lepidoptera:
Family Hesperiidae, Subfamily Pyrginae; Spread-wing Skippers
|
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Long-tailed Skipper
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Urbanus proteus
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Lepidoptera:
Family Hesperiidae, Subfamily Hesperiinae; Grass Skippers
|
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Dun Skipper?
|
Euphyes vestris?
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Order Hemiptera:
True bugs, cicadas, aphids
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Hemiptera:
Family Reduviidae; Assassin bugs
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Wheel Bug
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Arilus cristatus
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Order Diptera:
Flies
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Diptera: Family
Asilidae
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Robber fly
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Diptera: Asilidae
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Order Hymenoptera:
Ants, bees, wasps etc.
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Hymenoptera:
Family Formicidae; Ants
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Fire Ant
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Solenopsis invicta
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Order Coleoptera:
beetles
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Coleoptera: Family
Meloiidae; Blister Beetles
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Margined Blister Beetle
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Epicauta funebris
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Spiders
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Sheetweb Spider (web)
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Family Linyphiidae
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Yellow Garden Spider
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Argiope aurantia
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