Ramble Report August 1 2019

Today's Ramble was led by Linda Chafin.

Here's the link to Don's Facebook album for today's Ramble. (All the photos in this post are compliments of Don, unless otherwise credited.)

Today's post was written by Linda Chafin and Dale Hoyt.

Today’s Focus: Plants and Critters in the power line right of way.

32 Ramblers met today.

Announcements:

Tuesday, August 6^th, Betsy Collins and Kathy Stege are going to paddle at Tugaloo Lake at Tallulah Falls State Park. If you’d like to join them:

Meet at Kathy’s house at 9 to carpool or caravan. Address is 255 Rocky Dr. which is a right turn just before Sandy Creek Park if you’re coming from town. Or, meet at the boat ramp at the end of the dirt road by the entrance to Tallulah Gorge State Park at 10:30.

Let Kathy know you're coming; email: kath22steg AT gmail.com; phone: 478-955-3422

The Friends of the Georgia Museum of Natural History is hosting a monthly series of informal natural history talks. The talks will be given at the “Turtle Pond” (near the Ecology building on campus). Talks will occur on the first non-holiday Monday of the month, at 10am. The first talk is September 9; on Southeastern Mammal diversity by Nikki Castleberry.

Click here for more information and the complete schedule for the coming academic year.

The Friends will provide hot coffee (BYO mug!) and you should bring a folding chair if you have one.

Today's reading: Bob Ambrose recited one of his recently composed poems, A Summons:

Today's route: Through the Chestnut tree in the Children’s Garden to the White Trail and down the power line RoW to the river. Then left on the Orange Trail to the Orange Trail Spur and back to the White Trail and the Visitor’s Center.

OBSERVATIONS:

Children’s Garden:

 

Comfort Root (Hibiscus aculeatus)
photo by Hugh and Carol Nourse
(click to enlarge)

Okra flower (Hibiscus esculentus)
(click to enlarge)

The okra patch in the Children’s Garden is in full flower and fruit–both the green- and red-fruited varieties. Okra is in the same plant family (Mallow, Malvaceae) as hibiscus, hollyhocks, rose-of-sharon, and other ornamental plants but is the only edible member of the family. Linnaeus placed it in the genus, Hibiscus, and named it Hibiscus esculentus, meaning “edible hibiscus.” (It was later moved to the genus Abelmoschus, a name with an interesting story for another day.) Okra flowers look very similar to the southeastern native Comfort-root (Hibiscus aculeatus), that also has cream-colored flowers with a maroon center. They both have the whorl of narrow bracts surrounding the true calyx that is characteristic of Hibiscus. Okra has been cultivated in North Africa since the 12^th century BC. Jeff told us a story from his and Phyllis’s time in Chad in the 1960s: when he asked some Chadian farmers for the local name of the crop plant we know as okra, they replied “gumbo.”

Hibiscus flower diagram
(from http://www.hiddenvalleyhibiscus.com/newsletters/october2011.htm)
(click to enlarge)

One of the features that distinguishes Mallow family plants from other plant families is the peculiar arrangement of the stamens and the pistil. As you can see in Don’s photo, the stamens are fused together into a hollow tube, with the yellowish-white pollen-bearing anthers emerging at all levels along the outside of the tube. The female reproductive structure, the pistil, is mostly enclosed inside the tube with the stigmas surfacing from the top of the tube; the stigmas will eventually rise an inch or more above the tube. Pollinators are drawn in by the bright colors of the petals and by the contrasting colors of the nectar guides at the base of the petals. To reach the nectar glands, pollinators must insert their tongues or proboscises down the inside of the staminal tube to the nectaries that sit around the base of the pistil (see the drawing below).

A large pot-grown papaya towers over the vegetable beds in the Children’s Garden.(click to enlarge)

We stopped to admire a Tall Pawpaw tree planted beside the path through the Forest Play Area in the Children’s Garden. Hopefully, this means we’ll start seeing more Zebra Swallowtails in this part of the Garden, since Pawpaws are the obligate host for this elegant butterfly. (click to enlarge)

White Trail

Avis quickly found the first Cranefly Orchid of the morning not long after we started down the White Trail – there are many growing on this slope nearly all the way to the edge of the floodplain swamp.
(click to enlarge)

Eugenia and her grandkids found a moth pupa and showed it to everyone.

(click to enlarge)

One of the differences between moths and butterflies is in the pupal stage. The butterfly pupa is often a colorful, almost gaudy thing, often with iridescent golden bumps decorating it, or shaped like a dead leaf for camouflauge. A special name is given to the butterfly pupal stage: chrysalis, from Latin, meaning “golden”. The moth pupa is a brown object without decoration. It is often surrounded by a silken enclosure, called a cocoon. Sometimes the cocoon is tough and thick, in others it can be wispy and include the hairs from the last caterpillar stage. In still others pupation occurs underground in a chamber excavated an formed by the last caterpillar instar. And, in some, the pupa is naked, formed under a rock or log for protection.

A large, downed tree trunk is rapidly turning into dirt along the White Trail–it has reached the “sponge phase” and hosts a number of ants that use the softened wood as a nesting site.(click to enlarge)

White Avens fruits are a textbook example of adaptation for animal seed dispersal. Each part (called a carpel) of the seed head is tipped with a hooked beak that is easily picked up in the fur of passing animals. (click to enlarge)

The first of the late-summer composites are beginning to flower in the right-of-way:  Rough-leaved sunflower and Tall Ironweed, which towers over all the other plants. (click to enlarge)

Turkey Vulture basking–or perhaps sniffing out its next meal– atop the large power line pylons. Turkey Vultures find their food by their sense of smell rather than by sight.
 (click to enlarge)

The seed heads of Wild Rye, a cool-season grass that flowered in May, persist through the summer and fall and sometimes until the following spring.(click to enlarge)

Aphids on the underside of Yellow Crownbeard leaves.
(click to enlarge)

Wild Senna; the black knob above the Bush Cricket is an extra-floral nectary.
(click to enlarge)

Buds are forming in the axils of the few Wild Senna plants left in the right-of-way; most of these plants have been outcompeted by the aggressive Tall Goldenrod. At the base of Wild Senna’s leaf stalks, there is a small, shiny, reddish-green to black knob that is an extra-floral nectary (i.e. a nectar-producing organ not associated with a flower). The nectary exudes a sugary nectar that attracts ants and other insects, such as the Red-headed Bush Cricket. Ants return the favor by killing caterpillars that would otherwise munch on the Wild Senna leaves. While this is a fascinating plant-animal relationship, we regret to say that the caterpillars that meet their end in this way are the larvae of some of our favorite butterflies:  Cloudless Sulphurs (Phoebis sennae) and Sleepy Orange butterflies (Abaeis nicippe).

Daisy Fleabane plants still flowering along the edge of the ROW path.
(click to enlarge)

INSERT Bush Cricket images here.

Red-headed Bush Cricket nymph
The wing buds are the black structures just behind the red thorax.
At the next molt they will expand to the size seen in the photo below.
(click to enlarge)

Red-headed Bush Cricket adult
The wings are fully developed; compare with the wing buds on the nymph in the photo above.
(click to enlarge)

Red-headed Bush Cricket nymph from July 11 Ramble
Notice that the head is not red, but the thorax is.
(click to enlarge)

Red-headed Bush Crickets were seen in several places, but the most interesting was on the Wild Senna where they were sipping on the extra-floral nectaries. These nectaries are often thought to attract only ants, but they also attract other insects other than ants. These additional “bodyguards” may also eat any eggs or larvae they encounter.

We found both adults and nymphs today and all of them had the distinctive red head and thorax, unlike the one we saw on the July 11 Ramble – a nymph-stage cricket with a black head.

A Leaf-footed bug, Acanthocephala sp.
(click to enlarge)

Leaf-footed bug (Leptoglossus phyllopus, July 18 ramble)
(click to enlarge)

A large coreid bug (Order Hemiptera, Family Coreidae), probably a species of Acanthocephala, was seen on one of the wingstem plants. It resembles the common leaf-footed bug we have seen on other rambles, but is larger, has thicker, spinier legs and a smaller expansion of the tibia (the “leaf”) and lacks the transverse white band.

Peg-like haustoria of a Dodder about to plug into a host’s stem.
Credit: Stefan Lefnaer, Wikimedia Commons
(click to enlarge)

The bright orange strands of Common Dodder are climbing over and parasitizing plants on both sides of the path through the lower right-of-way. Dodder has no chlorophyll at all–it is entirely dependent on its host plants for nutrients, carbohydrates, and water. Each Dodder plant starts out life rooted in the soil, but once the stems reach a host plant and sink in their suckers, the roots wither away and the plant lives entirely off its host. The suckers look like little pegs and are called “haustoria,” a Latin word meaning “suck.”

Curly Dock was easy to spot with its dark reddish-brown seedheads
(click to enlarge).

A Gall is a name given to an abnormal growth on a plant. Galls have a variety of causes: bacteria, viruses, insects (aphids, flies, wasps), fungi. Some of the most interesting are those caused by insects. Today we saw three different insect caused galls, two on goldenrod and one on blackberry.

Goldenrod Rosette Gall
(click to enlarge).

The most common gall in the RoW is probably the Goldenrod Rosette Gall. It looks like a clump of leaves crowed together at the tip of the stem. You can imagine how such a gall could be formed. The goldenrod stem consists of a repeating series of leaves (the nodes) separated by leafless stem, the internodes. If you imagine the internodes failing to elongate as the stem grows you could produce a clump of leaves all smooshed together. This is likely how the rosette gall is formed. The cause is a fly, the Goldenrod Rosette Gall fly (a midge, Rhopalomyia solidaginis, in the family Cecidomyiidae). Earlier in the spring, when the goldenrod is approximately three feet tall, the overwintering flies emerge, mate and lay eggs in the growing tip of the plant. Some unknown substance is either introduced by the fly with her egg or produced by the fly larva after it hatches. This substance inhibits the normal elongation of the shoot, causing the leaves to clump together. Meanwhile the fly larva feeds on the plant tissue at the heart of the clump.

Why are the rosette calls all about the same distance from the ground? Because the adult flies live only a short time, when the goldenrod is only three feet tall. Those stems that the flies missed continue to grow normally.

Goldenrod Spherical Gall
(click to enlarge).

The second goldenrod gall is a spherical swelling of the stem, a little larger than a quarter but smaller than a golf ball. This gall is produced by a different fly, Eurosta solidaginis, in the family Tephritidae. The presence of the larva somehow induces the plant to produce a swelling in the stem and the larva feeds on the tissue that forms the gall. It overwinters as a larva and then pupates in the spring. Before pupation the larva eats an exit tunnel almost to the surface, but leaves the “skin” of the gall intact. When the adult fly emerges from the pupal stage it presses its head against the exit covering and swells a fluid filled balloon (called a ptilinium) from its forehead. The hydraulic pressure of the ptilinium breaks open the covering and the adult fly emerges into the spring air. The ptilinium withers away, leaving only a line on the forehead.

The thick, hard spherical gall would seem to provide protection for the maggot inside, but some birds have discovered that it contains a tasty morsel for a wintertime snack. The Chickadee and Downy Woodpeckers both can break open the gall and extract the overwintering larva. You can tell which predator has eaten the contents – the woodpecker makes a neater hole than the chickadee.

What keeps the larva from freezing to death during a cold winter? In the fall it starts to produce an antifreeze in its blood that protects it from subzero temperatures.

Blackberry Knot Gall
(click to enlarge).

The Blackberry Knot Gall is a large knobby growth on a blackberry stem. It is caused by the Blackberry Knot Gall Wasp (Diastrophus nebulosus), which lays its eggs in the blackberry stems during the spring and summer. The plant responds to this invasion by forming a multi-chambered gall, each chamber isolating (from the plant’s perspective) and protecting (from the wasp’s perspective) just one egg. After the eggs hatch, the larvae overwinter in the gall, eating the plant tissue that makes up the gall. The following spring, adult wasps chew their way out of the gall and then begin their own search for blackberry stems to host the next wasp generation–unless hungry birds discovered the gall midwinter, and pecked their way into the juicy larva treats inside the gall.

Even though it is a wasp it cannot sting. It belongs to the family Cynipidae, all of which are gall makers. They are quite tiny, only a little larger than fruit flies. They were made famous by the man who first studied them: Alfred Kinsey. You may recognize the name. Before he started his studies of human sexual behavior he was the world authority on cynipids.

We often find Oak Apple Galls on our rambles. They are formed on oak leaves by another cynipid wasp.

Virginia Dayflower is in bloom along the edge of the ROW path.
(click to enlarge)

 Asymmetrical leaf bases of American Elm. This type of leaf base (“oblique”) is found in all elms but is most conspicuous in American Elms.
(click to enlarge)

Bark of an immature American Elm tree.
(click to enlarge)

Bark of a mature American Elm tree
(photo credit: Sri Mesh, Wikimedia Commons)
(click to enlarge)

Don’s photo of Winged Elm bark perfectly captures the tongue-depressor appearance of the rounded, oblong scales that characterize its bark.
(click to enlarge)

There are many Winged Elms throughout the Garden–they grow in almost any habitat from wet floodplains to dry ridges and upper slopes. American Elms also occur at the Garden but are restricted to wet areas in the floodplain. There is also Slippery Elm in the Dunson Garden. To our knowledge, Dutch Elm Disease has not been a problem at the Garden and, generally speaking, is much less of a threat to elms in the southern states than in northern states, probably because American Elms were not planted in monocultures in the south. You can find a good discussion of Dutch Elm disease here. The fungal disease was introduced to this country in the 1920s by furniture makers who imported elm logs from Europe for veneer; the beetles that spread the fungus was introduced years before that.

Antlion larva (AKA Doodlebug)
(click to enlarge)

Antlion pit trap
photo credit: http://en.wikipedia.org/wiki/User:VirenVaz Viren
(click to enlarge)

An adult antlion; 
photo credit: dhobern [CC BY2.0(https://creativecommons.org/licenses/by/2.0)]
(click to enlarge)

Antlions (Doodlebugs)

I was surprised to see, as we entered the woods on the Orange Trail, the funnel-shaped traps of antlions in the fine sand at the edge of the trail. Antlions (or doodlebugs) are the larval stages of insects in the Order Neuroptera (net-winged insects). The adults are seldom seen and resemble gangly damselflies. The larval stage is also unseen by most people but many are familiar with the pit traps that they construct. The cone shaped traps are usually found in fine sand or dust in protected locations, like under a carport or the eaves of a house. The larva is a peculiar creature, with a rounded, oval abdomen, a flat, projecting thorax and a pair of mandibles shaped like old fashioned ice tongs. In addition, the larva can only move in one direction, backwards. It constructs its conical pit trap by moving backwards, just under the surface of the sand, in an ever-decreasing spiral, throwing the sand aside by snapping its head and thorax upward. As it proceeds along its spiral path it gradually sinks lower and lower in the sand until it comes to occupy the center of the conical depression it has just made. It lies there, buried in the bottom of its pit, waiting for an insect to tumble into its trap. When an ant stumbles into the edge of the pit the sand gives way, alerting the antlion below. It uses its head and thorax to flip more sand out of the pit, causing the ant to fall further downward. It can even direct the sand toward its prey, increasing the likelihood that it will fall into the death zone at the bottom. When the ant reaches the bottom of the pit it is quickly seized in the pointed mandibles of the antlion and injected with a poison the rapidly kills the ant. The antlion then uses the hollow mandibles to suck the juices until only a dried husk remains of the ant. With a dexterous flip of the head, the ants body is hurled out of the pit and the antlion is ready for its next prey.

If the trap is not productive for a day or more the larva will abandon it and, moving backwards as always, it will scoot in a meandering, somewhat random direction, creating a path in the sand that reminds you of the mark a child might make in a sandbox with their fingertip. This is the origin of its other common name: “doodlebug.” When it stops wandering it builds another trap and resumes waiting.

Susie remarked that she had never seen a doodlebug, so I dug one up to show her. All you need is something like a spoon. Push the spoon quickly into the sand next to the lowest point of the pit and extract a spoonful of sand from the center. Carefully scatter the sand over your hand or a piece of paper and shake of off, gently. If you were quick enough you will soon see the little antlion. He will look like a moving clot of sand or dirt; the motion and the sickle-shaped jaws will give it away.

Here’s a video of an antlion making a pit and capturing an ant.

Both species of Virgin’s Bower are growing in the right-of-way:  The native Virgin’s Bower (L), with its toothed leaflets, and the invasive Asian species, often called Autumn Sweet Clematis (R), with its non-toothed leaflets.(click to enlarge)

Eastern Anglepod in flower. The uppermost flower has attracted a fly with its maroon color. Photo by Hugh and Carol Nourse.
click to enlarge)

Several Eastern Anglepod (aka Milkvine or Climbing Milkweed) plants are hanging on along the trail, getting enough sunlight to survive but not enough to flower. Several years ago we found flowers in this population (see photo above) but the canopy has closed in enough over the years so that no flowers were produced this year.

Post-Ramble Presentation by Berkeley Boone:

Berkeley Boone, the Children’s Program Manager at the Garden, showed us some reptiles from his personal collection. (He brought them in to show one of the classes.) Here they are:

Alligator Snapping Turtle
The fleshy tongue in the lower jaw is wiggled, with the mouth open, to attract fish.
Then: Chomp!
(click to enlarge)

Eastern Box Turtles(click to enlarge)

Louisiana Pine Snake
(click to enlarge)

Black Rat Snake
(click to enlarge)

SUMMARY OF OBSERVED SPECIES

Okra	Abelmoschus bammia
Papaya	Carica papaya
Paw Paw	Asimina triloba
Cranefly Orchid	Tipularia discolor
Winged Elm	Ulmus alata
Moth (pupa)	Order Lepidoptera
Ant	Family Formicidae
Crossvine	Bignonia capreolata
White Avens	Geum canadense
Box Elder	Acer negundo
Poison Ivy	Toxicodendron radicans
Rough-leaved Sunflower	Helianthus strumosus
Tall Goldenrod	Solidago altissima
Tall Ironweed	Vernonia gigantea
Wild Rye	Elymus glabriflorus
Aphids	Family Aphidae
Yellow Crownbeard	Verbesina occidentalis
Wild Senna	Senna marilandica
Turkey Vulture	Cathartes aura
Daisy Fleabane	Erigeron sp.
Red-headed Bush Cricket	Phyllopalpus pulchellus
Large Brown Bug	Coreidae: Acanthocephala sp.
Common Dodder	Cuscuta gronovii
Curly Dock	Rumex crispus
Blackberry	Rubus sp.
Blackberry Knot Gall	Hymenoptera: Cynipidae: Diastrophus nebulosus
Cinnamon Vine	Discorea batatas
Virginia Dayflower	Commelina virginica
Virgin’s Bower	Clematis virginiana
River Oats	Chasmanthium latifolium
Sand Bean	Strophostyles helvula
American Elm	Ulmus americana
Antlion	Order Neuroptera: Myrmeleontidae
Common Whitetail dragonfly	Plathemis lydia
Sweet Autumn Clematis	Clematis terniflora
Ground Ivy	Glechoma hederacea
Climbing Milkvine	Gonolobus suberosus