September
8, 2022 Nature Ramble Report
Co-leaders
for today’s Ramble:
Heather and Bill
Authors
of today’s Ramble report: Heather, Bill, and Don. Comments and suggestions for improvements to the report can be sent to Linda at Lchafin@uga.edu.
Link to Don’s Facebook
album for this Ramble. All
the photos that appear in this report, unless otherwise credited, were taken by
Don Hunter.
Number
of Ramblers today:
16
Today’s
emphasis: Heather took care of the spiders, caterpillars, and other insects;
Bill took care of the galls and fungi.
Announcements/Interesting
Things to Note:
Emily
shared a link to an interesting article from the Cincinnati Nature Center on
Goldenrod Galls.
The
Garden’s annual celebration of insect and spiders – Insectival – is coming
Saturday, September 17. For more information, click here.
The
Garden is holding its 11th annual native plant sale at the Mimsie
Lanier Center for Native Plants, October 6,7,8 and 13,14,15, Thursdays and Fridays, 4–6 p.m. and Saturdays,
9 a.m.–noon. For a list of available plants, email Linda.
Show-and-Tell:
Dale
brought an oak leaf he found on the sidewalk that had been browsed by a
caterpillar, with much of the leaf missing on one side of the midvein (left). Birds
learn to identify leaves damaged like this by caterpillars and concentrate
their search for a caterpillar on such leaves. To reduce discovery by birds,
some caterpillars chew through the petiole (leaf stalk), dropping the leaf to
the ground partway through their meal. The longer a caterpillar lingers on a particular
leaf, the greater its chance of discovery by a bird. It’s safer for the
caterpillar to abandon a partly eaten leaf and move on after getting rid of the
evidence that they were there. You can spot such leaves by examining the petiole.
A leaf that has been abandoned by a caterpillar will have a partly eaten blade and truncated petiole (center). A leaf that has dropped naturally will
have an expanded petiole base where the leaf was attached to the twig (right).
Gary
brought an old nut from what looks to be a Sand Hickory. Bill suspected that outgrowths with exit holes on the surface
of the nut may actually be insect galls. He posted to iNaturalist
and asked some amateur gall experts. They concurred that the galls may have
been made by a rare gall midge, Harmandiola nucicola
(from the same family of tiny flies, Cecidomyiidae, that made some of the galls
on goldenrod we would later see in the right-of-way).
Reading: Bob read a short poem, “Choices,” by Tess
Gallagher:
of the house to cut
saplings,
and clear a view to
snow
on the mountain. But when I look up,
saw in hand, I see
a nest clutched in
the uppermost
branches.
I don’t cut that
one.
I don’t cut the
other either.
Suddenly, in every
tree,
And unseen nest
Where a mountain
Would be.
Today’s
Route: We left the Children’s Garden arbor and made
our way through the Shade Garden to the powerline right-of-way, where we took the paved
path down to the river. We then retraced
our way back up to the road and headed left and into the the
large mulch pile area and adjacent drainage, eventually exiting back out into the
right-of-way, and headed back to the Visitor Center and beyond.
OBSERVATIONS:
At the entrance to the Shade Garden, Heather saw a Gulf Fritillary caterpillar eating a Passionflower bud. Gulf Fritillary is one of the few species to use Passiflora, the genus of passionflowers, as a host plant. The caterpillar’s spines look scary but do not sting, though the caterpillar is toxic to birds if eaten. Gulf Fritillary butterflies produce multiple generations each year, some emerging as butterflies this year and some overwintering in their cocoons to emerge in spring next year. Heather has noticed that they’re late this year and most of these caterpillars may overwinter.
As
we all know, Joros are a new-ish invasive species, arriving from Japan in
2013. They continue to spread along the east coast, and have raised fears about their impact on native spider populations. Early research is beginning
to show that they may not actually be having much of an effect. Heather
has noticed fewer of them this year, and speculates that they’re competing
with each other, rather than native spiders, for food. She reports having seen as many native
orb weavers as in years past. More info on Joros at this link.
 |
| Florida Fern Moth caterpillar dining on Mariana Maiden Fern |
Despite
the name, Florida fern moths range from Florida to South Carolina and eastwards
though Texas and Mexico. Its caterpillar has five color forms: a light-green
form; a green form with an upper white line and a lower black line down each
side; a form with the upper and lower white and black lines down each side plus
black spots on the back and upper sides; a velvety dark-striped or black form;
and a velvety dark-striped or black form with a white line down each side.
Sometimes green caterpillars occur with thin, pale, yellow stripes on the back
and bold, white stripes on each side.
 |
| Galls on American Witch-hazel leaves |
These galls were created by the Witch-hazel Cone Gall Aphid and are
part of a complex reproductive scheme that involves time spent on birch trees. Bill
dissected one of the galls to show the interior living space (center) and two exit holes
on the underside of the leaf (right).
 |
| Arrow-shaped Orbweaver |
An Arrow-shaped Orbweaver had spun her orb in a bed of Japanese Sacred
Lily. A
common spider in forested areas, these orbweavers live close to the ground in shady areas. The females’ abdomens come with a pair of small, forward-pointing spines; there are also two large, spreading spines that extend from the base of the abdomen into red, black-tipped points. Males have no spines or points at all.
Here’s more info on this species.
 |
| Arrowhead Spider/Triangulate Orbweaver |
We saw several different Arrowhead Spiders (aka Triangulate Orbweavers)
in beautiful, well constructed orbs suspended high in the air between large shrubs. Most
orbweavers sit with their legs out and face down in the middle of their webs,
but this species actually pulls its legs in and sits head upwards instead! They
have keen eyesight and will retreat to an upper branch and hide if they are
being observed too long by humans.There is more info at this link.
 |
| Red-femured Orbweaver |
Adding
to the list of spiders we encountered in the Shade Garden was a Red-femured
Orbweaver in a nice, vertically oriented, oblong orb. These large orbweavers can be
found in the middle of their webs and upside-down, or if the web is empty, they
may be curled up and hiding on the lower surface of a nearby leaf. Baby spiders
of this species are targeted by Potter’s Wasps to feed their young.
 |
| Huge pellets of caterpillar frass, possibly from a Hickory Horned Devil, the largest caterpillar that Dale knows, littered the Shade Garden path. |
A search of the Passionflower vines growing on the deer fence around the Dunson Native Flora Garden is obligatory this time of year. We were rewarded with Gulf Fritillary caterpillars munching on Passionflower leaves and a surprise guest doing likewise: a Saddleback Caterpillar.
Saddleback caterpillars are a no-touch friend, as they sting. The
hairs contain a venom that may induce migraines, asthma, anaphylactic shock,
and hemorrhaging. The stinging hairs should be removed as soon as possible to
prevent the venom from spreading. Sticky tape is an effective means of removing
the hairs.
Saddlebacks are in the genus of slug caterpillars, which include
many other stinging caterpillars. They don’t have legs like most caterpillars,
relying instead on mucus and suckers (like slugs) to help them move. This
caterpillar will soon spin a tough, spherical cocoon surrounded by silk webbing
in which a pupa will overwinter. Come spring, the Saddleback Caterpillar Moth
emerges, mates, and lays up to 50 eggs at a time on leaves of various shrubs
and trees.
Our first stop in the powerline right-of-way was below the road in
a patch of Tall Goldenrod, a species known to support several different types
of galls. Goldenrods in general are known to host up to 50 different types of
insect galls.
 |
| Carboniferous Goldenrod Midge gall |
Carboniferous Goldenrod Midge galls were found on the leaves of Tall Goldenrod. This interesting gall is a mutualism between a gall midge
and a fungus. A mother gall midge lays an egg on a goldenrod leaf together with
a fungus spore. The fungus grows to form a white capsule (the gall) that provides both food and protection for the growing
midge larva. The “carbon” in the name is a tough
carbon layer (visible if you scrape away the white material) that provides
protection from parasitoid wasps. For more on this fascinating story, see this post.
 |
| Goldenrod Bunch Gall |
Tall Goldenrod in the right-of-way seems especially susceptible this year to Goldenrod Bunch Gall, a gall formed by a midge that has a complicated life cycle. The
gall shown here formed after a Goldenrod Bunch Gall Midge laid an egg in the
top-most leaf bud on the plant in June. The stem of the goldenrod stopped
growing vertically but thickened and produced leaves in a tight cluster at the
site of the egg implantation. Smaller branching stems as seen in the leftmost
photo often form below the gall. The dense growth of stem and leaves provides protection
and food for the midge larva housed within gall (center photo), as well as for many
other insect species that shelter among the leaves.
When the larva matures in
September, it drops to the ground and burrows into a goldenrod rhizome, where it
overwinters. When spring arrives, the larva emerges and produces a small,
inconspicuous gall where it quickly pupates and emerges as an adult. It is this
generation of adults that mates and lays the egg that stimulates the formation
of the large, showy bunch gall in June. After dissecting this gall, Bill
determined that the midge had already flown the coop (right photo). There are several bunch galls on Tall
Goldenrod made by different gall midges that can be distinguished using David
McClosky’s handy guide on iNaturalist.
Earlier this week, Bill and Don searched the right-of-way in vain for Goldenrod Ball Galls, and offered a free soda to anyone finding one during the ramble. Gary rose to the challenge by finding not one, but two, ball galls!
Bill
dissected the gall and found a squirming white larva of the Goldenrod Gall Fly inside. The fly that makes this gall is much larger
than the gall midges (Cecidomyiidae) that make the Goldenrod Bunch Galls and Carboniferous Leaf Galls described above.
 |
| Muscadine leaf infested with Phylloxera |
Grape Phylloxera is an
insect native to North America that has spread nearly
worldwide and become a serious threat to the grape and wine industry. A microscopic, aphid-like insect, it sucks sap from the leaves
and roots of grape vines. In roots, it forms
nodules that cut off the flow of water and nutrients to the aboveground parts
of the plant. American grapes are resistant to this pest:
they exude a sticky sap that usually foils the nymphs when they try to extract
sap, and, if the nymphs do penetrate the root, the vines form a
protective scab over the wound that prevents secondary infections by bacteria
and fungi. There is neither cure or pesticide treatment for Phylloxera. The only way of controlling the insects is to graft European
vines to resistant American grape rootstock. Phylloxera devastated the European wine
industry in the mid-19th century; more than two-thirds of
French vineyards were destroyed before the grafting technique was adopted. “The
Great French Wine Blight” and its resolution are chronicled in this Wikipedia
entry.
 |
||
| Phylloxera galls on the lower surface of a Muscadine Grape leaf. The photo on the right shows a slit in the gall from which the insects are emerging. |
 |
| Alternate-leaf Wingstem with stem gall. On the right, the gall is dissected and a yellow pupa is revealed. |
 |
| American Dagger Moth caterpillar on a Redbud leaf |
Several American Dagger Moth caterpillars were feasting on the
leaves of an Eastern Redbud tree near the paved path. Though warm-and-fuzzy in
appearance, they do sting. There are five bunches of black hairs mixed in among
the white (or sometimes yellow) hairs that coat their bodies. Four of the black
bunches are harmless but the black hairs in the bunch near the rear can break
off if brushed and release a venom that is painful and can cause a rash. They do rear up and look threatening when
touched, so take heed! Golden Jumping Spiders are known to hunt these particular
caterpillars.More info is here.
 |
| Cloudless Sulphur caterpillar on Maryland Senna |
You
can distinguish the adults of Cloudless Sulphur butterflies from their
look-alike, the Clouded Sulphur, by the lack of a black border on the wings. There
are some wonderful images and good info at this link.
 |
| Oblique Streaktail Hover Fly |
Hover Flies and Sweat Bees share some similarities but you
can always tell a fly because their giant eyes take up most of their heads.
Bees’ eyes are smaller in proportion to their heads. Hover Flies do exactly as
their name suggests: they hover. They can hover in near-perfect stillness
except for their wings, whereas bees cannot. More info about distinguishing between these similar groups of insects is here.
Having worked our way back to the service road, we crossed over to the clearing that the Garden uses for mulch piles, christened by Don as the “ An amazing diversity and abundance of mushrooms are flourishing there.
 |
 |
| Onion-stalk Parasols covered with guttation droplets Guttation in plants is a thoroughly researched phenomenon, but is not well understood in fungi. It seems to be associated with rapid growth. Guttation droplets can be clear, black, red, amber, purple, or other colors, depending on the species. There are some wonderful images of mushroom guttation here. |
 |
| Fluted Bird’s Nest Fungus |
Bird’s
Nest Fungi are super cool because they use raindrops to disperse their spores. When rain drops fall heavily into the cup-shaped fungus, the water splashes some of the little ‘eggs’ out of the nest. The ‘eggs’ unwind
a cord behind them that is caught on anything nearby. Once the ‘egg’ dries
out, it splits open, dispersing spores at a taller height than it
would have done otherwise. Here’s a very short video of this process.
 |
| Colorful though unidentified mushrooms on the mulch pile |
The woods near the mulch piles are dominated by oaks and hickories, rich sources of galls.
 |
| Bitternut Hickory leaves and buds |
Bitternut
Hickory differs in several ways from the more common hickories we see at the
Garden. It usually occurs near streams and in low, moist areas; its leaves have
7-11 leaflets; and the buds at the tips of its twigs are flattened and
covered with yellowish scales. The bark on mature trees is not as deeply braided as that of
Mockernut and Pignut, the other common hickories in the Garden’s forests.
Bitternut
Hickory also supports a type of midge gall found on no other hickory. The galls are found mostly
on the upper surface of the leaflets and are slender, pointed, leaning cones (photo left). Similarly
shaped galls are common on the lower surface of other hickory species leaves, but this
gall is found mostly on the upper leaf surface and only on Bitternut Hickory. The pupa of this midge can be seen in the dissected gall, photo right. Bill has documented this unusual gall on iNaturalist.
Water Oak leaf with Furry Oak Leaf Gall, created by a wasp on the upper surafce of the leaf. Documented by Bill on iNaturalist here.
 |
| Carolina Praying Mantis on a Water Oak leaf |
 |
| Black Treehopper |
 |
| A Margined Calligrapher Hover Fly working the flowers of Yellow Indian Grass |
 |
| A Tobacco Budworm Moth caterpillar (tentative ID)
munching on a grass flower stalk |
 |
| Rice Stink Bug, one of the smaller stink bug species |
 |
| Ramblers framed by Silver Plume Grass in the restored prairie. The largest native grass in the Piedmont, this species’ seedheads are in the their silvery-pink, feathery state, prior to actually flowering. |
SUMMARY OF OBSERVED SPECIES
Gulf
Fritillary (caterpillar) Agraulis
vanillae
Purple
Passionflower Passiflora incarnata
Joro
Spider Trichonephila clavata
Mariana
Maiden Fern Macrothelypteris
torresiana
Florida
Fern Moth (caterpillar) Callopistria
floridensis
American
Witch-hazel Hamamelis virginiana
Witch-hazel
Cone Gall Aphid Hormaphis hamamelidis
Arrowhead
Spider/Arrow-shaped
Orbweaver Micrathena sagittata
Sacred
Lily Rohdea japonica
Red-femured
Orbweaver Neoscona domiciliorum
Saddleback
caterpillar Acharia stimulea
Tall
Goldenrod Solidago altissima
Carboniferous
Goldenrod Gall midge Asteromyia
carbonifera
Goldenrod
Bunch Gall midge Rhopalomyia solidaginis
Goldenrod Gall Fly Eurosta solidaginis
Oblique Streaktail hover fly
Allograpta obliqua
American Dagger Moth (caterpillar) Acronicta americana
Eastern Redbud Cercis
canadensis
Eastern Tiger Swallowtail Papilio
glaucus
Muscadine grape Muscadinia
rotundifolia
Grape Phylloxera Daktulosphaira
vitifoliae
Cloudless Sulphur (caterpillar)
Phoebis sennae
Maryland Senna Senna marilandica
Alternate-leaf Wingstem Verbesina
alternifolia
Alternate-leaf Wingstem gall
Fruit fly pupa Eutreta
rotundipennis, Family Tephritidae
Fluted Bird’s Nest Fungus
Cyathus striatus
Onion-stalk Parasol
Leucocoprinus cepistipes
Trooping Crumble Cap fungus/Fairy Inkcap Coprinellus disseminatus
Fragile Dapperling
Leucocoprinus fragilissimus
Southern Crownbeard
Verbesina occidentalis
Carolina Anole Anolis
carolinensis
Black Treehopper Acutalis
tartarea
Bitternut Hickory Carya
cordiformis
Hickory Midge Gall midge
Caryomyia spinulosa
Water Oak Quercus nigra
Cynipid wasp gall Family
Cynipidae
Lesser Willow Sawfly (larvae)
Nematus pavidus
Carolina Praying mantis (tentative) Stagmomantis carolina
Silver Plumegrass Erianthus alopecuroides
Tobacco Budworm Moth (caterpillar)(tentative) Heliothis virescens
Rice Stink Bug Oebalus
pugnax
Margined Calligrapher syrphid fly Toxomerus
marginatus
Hickory Horned Devel/Regal Moth (frass)(tentative)
Citheronia regalis