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:
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:
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.
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| 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.
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| 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).
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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. | |
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| Alternate-leaf Wingstem with stem gall. On the right, the gall is dissected and a yellow pupa is revealed. |
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| 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.
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| 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.
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| 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.
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| 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. |
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| 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.
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| Colorful though unidentified mushrooms on the mulch pile |
The woods near the mulch piles are dominated by oaks and hickories, rich sources of galls.
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| 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.
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| Carolina Praying Mantis on a Water Oak leaf |
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| Black Treehopper |
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| A Margined Calligrapher Hover Fly working the flowers of Yellow Indian Grass
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| A Tobacco Budworm Moth caterpillar (tentative ID)
munching on a grass flower stalk |
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| Rice Stink Bug, one of the smaller stink bug species |
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| 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
