Sunday, September 10, 2017

Ramble Report September 7 2017




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.

Gulf Fritillary egg on Passionflower tendril
Gulf Fritillary caterpillar
Gulf Fritillary chrysalis 
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.

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.)

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.

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!

Southern Flannel Moth (?) caterpillar

Long-tail Skipper caterpillar

Saddleback caterpillar

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.

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.

Katydid on Passionvine fruit

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.

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
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.

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.

Wingstem; note alternate leaf arrangement

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.]

Tall Ironweed

Late-flowering Thoroughwort

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:

Flowering Plants
Nodding Ladies Tresses
Spiranthes cernua
Purple Passion-flower
Passiflora incarnata
Heliotrope
Heliotropium amplexicaule
Rabbit Tobacco
Pseudognaphlium obtusifolium
Brazillian Vervain
Verbena brasiliensis
Camphorweed
Pluchea camphorata
Common Evening-primrose
Oenothera biennis
Rough-leaf Sunflower
Helianthus strumosus
Wingstem
Verbesina alternifolia
Yellow Crownbeard
Verbesina occidentalis
Frostweed
Verbesina virginica
Common Ragweed
Ambrosia artemisifolia
Tall Ironweed
Vernonia altissima
Sand Bean
Strophostyles helvola
Tall Thistle
Cirsium altissimum
Dotted Smartweed
Persicaria punctatum
Late-flowering Thoroughwort
Eupatorium serotinum
Tall Goldenrod
Solidago altissima
Vertebrates
Carolina Anole
Anolis carolinensis
Insects
Orthoptera – Grasshoppers, Katydids, Crickets
Orthoptera: Family Tettigoniidae; Katydids
Short-winged Meadow Katydid
Conocephalus brevipennis
Katydid
Family Tettigoniidae
Lepidoptera – Butterflies & Moths
Lepidoptera: Family Nymphalidae, Subfamily Heliconiinae
Gulf fritillary
Agraulis vanillae
Lepidoptera: Family Nymphalidae, Subfamily Nymphalinae
Silvery Checkerspot
Chlosyne nycteis
Lepidoptera: Family Megalopygidae; Flannel Moths
Southern Flannel Moth?
Megalopyge opercularis
Lepidoptera: Family Limacodidae; Slug Moths
Saddleback caterpillar
Acharia stimulea
Lepidoptera: Family Erebidae, Subfamily Arctiinae; Tiger Moths
Giant Leopard Moth?
Hypercompe scribonia
Fall webworm
Hyphantria cunea
Lepidoptera: Family Hesperiidae, Subfamily Pyrginae; Spread-wing Skippers
Long-tailed Skipper
Urbanus proteus
Lepidoptera: Family Hesperiidae, Subfamily Hesperiinae; Grass Skippers
Dun Skipper?
Euphyes vestris?
Order Hemiptera: True bugs, cicadas, aphids
Hemiptera: Family Reduviidae; Assassin bugs
Wheel Bug
Arilus cristatus
Order Diptera: Flies
Diptera: Family Asilidae
Robber fly
Diptera: Asilidae
Order Hymenoptera: Ants, bees, wasps etc.
Hymenoptera: Family Formicidae; Ants
Fire Ant
Solenopsis invicta
Order Coleoptera: beetles
Coleoptera: Family Meloiidae; Blister Beetles
Margined Blister Beetle
Epicauta funebris
Spiders
Sheetweb Spider (web)
Family Linyphiidae
Yellow Garden Spider
Argiope aurantia

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