Ramble Report August 12 2021

Leader for today's Ramble: Dale

Authors of today's Report: Linda (plants), Dale (animals)
Link to Don's Facebook album for this Ramble. All photographs in this post were taken by Don Hunter unless otherwise credited.
Number of Ramblers today: 30
Today's emphasis:  Looking for pollinators in the flower beds at the Porcelain and Decorative Arts Museum, the Herb and Physic Garden, the Heritage Garden and the Flower Garden.  This was a refresher on identifying basic types of pollinators in advance of the upcoming Great Georgia Pollinator Census, August 20-21, 2021
Reading:  Dale read an excerpt from the August 12 entry in An Almanac for Moderns, by Donald Culross Peattie.

One can never look long In the August sky without beholding a shooting star, for the trail of the Perseids is spun fine at each end; only last night and tonight we pass through the thick node of them. If we ask ourselves what is a meteor - fragment of the lost planet between Mars and Jupiter, messenger from the farthest stars, or bit of a vanished comet - there seems no certain answer. The Perseids are thought to be traveling in the same orbit as that of Tuttle's comet of 1862, and to be a part of it. But what, after all, is a comet? Nothing more ghostly exists in time or space; it rushes at us out of a black hole of space, trails a fire that does not burn, a light that is no light, and looping close to the sun, vanishes again into space - to return at the appointed time when the sea of darkness again gives up its dead; or, more terrible still, never to return from its Avernus.
Note: Avernus is a volcano located near Naples, Italy

Show & Tell:

Carla brought some Purple Coneflower suffering from yellow asters disease. For more information about the yellow asters disease read this data sheet. Announcements:
"       Emily made a plea for considering use of masks while we are rambling in close quarters.
"       Don mentioned the Slime Mold experiment to be conducted on the International Space Station.
"       Gary "apologized" for his misinformation about snail sex last week.
 

Today's Route: The Porcelain and Decorative Arts center garden beds, then to the Physic Garden, Freedom Plaza and the Heritage Garden.
 

OBSERVATIONS:

 

Three-nerved Joe-Pye-Weed flower heads.

The new beds around the Porcelain Museum feature a cultivar of Three-nerved Joe-Pye-Weed called “Little Joe.” Three-nerved Joe-Pye-Weed is found primarily in the Coastal Plain and is uncommon in Georgia. It has a narrow, hard, solid stem. The Joe-Pye-Weed we north Georgia folks are most familiar with is Hollow-stem Joe-Pye-Weed; its stem is wider and, since it is hollow, gives under pressure. The north Georgia species can reach 11 feet in height, while “Little Joe” is typically 3-4 feet tall. Both of these species are pollinator magnets and are good candidates for the Great Georgia Pollinator Census coming up on August 20-21. Joe Pye is believed to have been a Native American herbalist. Leaves and roots of these species have been used to treat a wide variety of illnesses from rheumatism to impotence.

 

Swamp Milkweed plants

Hundreds of Swamp Milkweed were planted in the garden area behind the Porcelain Museum to attract Monarch butterflies. We saw several adults and caterpillars. There are two varieties of Swamp Milkweed; ours is variety pulchra, with the common name of Eastern Swamp Milkweed. Since this bed was planted only recently, few of the plants flowered this summer. In coming years, this bed will be a sea of dark pink flower heads earning the name “pulchra” –  Latin for “beautiful.”

 

Sweet Bay Magnolia flower

Sweet Bay Magnolia aggregate fruit

Sweet Bay Magnolia ripe fruits

Sweet Bay Magnolia trees behind the Museum are laden with an unusual kind of fruit called an “aggregate,” so called because it develops from many separate pistils held in a single flower. The aggregate starts out as a small, green, lumpy fist; shortly, the lumps (individual pistils) blush pink as they swell into separate, one-seeded fruits, each with a noticeable line where they will eventually open. Finally, at maturity, each fruit opens and a bright red seed emerges. Aggregate fruits are found in the oldest flowering plants such as magnolias and blackberries. It is thought that, over millions of years of evolution, the ovaries of more modern plants, such as apples and blueberries, fused into a single fruit thought to be more attractive to fruit-eating animals.
 

Purple Coneflowers

Purple Coneflowers provide nectar throughout the day, which makes them especially valuable to their pollinators; most other day-flowering plants produce the most nectar in the morning. Insects search for nectar in the tiny, orange flowers found in the central “cone”; the showy, pink ray flowers are just “for looks,” drawing in pollinators. However, the jury is still out on whether cultivars, such as this one, provide pollen and nectar of the same quality and quantity as do the straight species. For a good discussion of this issue, see: https://xerces.org/blog/cultivar-conundrum
 

Cock's Comb inflorescence

Cock's Comb
Seed producing flowers on stem

Cock's Comb seeds on stem

Cock’s Comb is such a strange-looking plant. The large inflorescence looks like a brain with none of the features we expect from a typical flower. But its bright color attracts bees that probe for nectar in the inconspicuous, seed-producing flowers that crowd the stems just below the showy crest. Amazingly, it is an important food plant in large parts of the tropical world: “[Related] to amaranth, the cockscomb is…the most widely used leafy vegetable in southern Nigeria, and is also part of the diet in Benin, Congo and Indonesia…Even young stems and flowers are eaten.” (Wikipedia) the shiny black seeds shown in Don’s photo are also eaten.
 

A small area of the new museum garden is dedicated to aquatic and wetland plants such as Venus’s Flytrap, Horse-tails, Spider Lilies, and White-topped Sedge.
 

Flowers of White-topped Sedge, with bright white floral bracts, are the only sedge flowers pollinated by insects. Other members of this family have green flowers that are wind-pollinated.

Blue Sage has the conspicuously two-lipped flowers of the mint family.

Colorful leaves and flowers of a cotton cultivar.

Flowers of the Loofah plant.

Why it's safe to watch foraging bees and wasps.
 No one wants to be stung, so why should we not be worried about getting stung when we're close enough to identify the bees?

First, what bees and wasps will sting you? Most stings come from the social bees and wasps. These are the honey bees, bumble bees, paper wasps, yellow jackets and hornets. Among these social insects there is a division of labor among the females in the nest or hive. Some of the workers stay in the hive and take care of the larvae, feeding them and repairing the nest and defending the nest. It is the nest defenders that will rush out and sting if you draw near and/or disturb the nest. The foragers that we see on flowers are intent on their job: gathering pollen and/or nectar. They are focused on that activity and will not be disturbed by your presence. The only way you will be stung by a forager is if you physically restrain them. 

Also, keep in mind that wasps are carnivores. They are hunting for caterpillars or other arthropods. When they visit flowers they are looking for a little nectar to fuel their search for something to eat. While preoccupied in that search they won't bother you. So don't hesitate to get your face up close to the flowers to see what is really going on.  

 

Of course, if you have an allergic reaction to bee or wasp stings don't expose yourself to any risk, no matter how small.

 

Why are bees so good at pollination?

Bees are covered in bristles and those bristles are branched. This makes them much more effective in gathering pollen all over their body. They are so effective that plant breeders often use the thoraxes of dead honey bees to cross polinate their plants. If bee thoraxes aren't available cotton swabs can be used, but they're not as good.

 

Fiery Skipper on Vervain
Notice how the wings are held a different angles.

Ocola Skipper on Vervain
The hind wings are held horizontally,
the front wings almost vertically.

Are skippers butterflies?

The short answer to this question is: skippers are a type of butterfly. Butterflies fly diring the day, have club-shaped antennae, generally hold their wings together over their back when at rest, have small bodies in comparison to the size of their wings. 

Skippers fly during the day, have club-shaped antennae, but the club ends with a pointed hook, generally hold their hind wings horizontally and their front wings slightly open, have large, fuzzy bodies in comparison to the size of their wings. The question is really about are they different enough to merit a status equivalent to that of the butterflies. At one time the skippers were classified in the superfamily Hesperiodea and the butterflies in the superfamily Papilionoidea. More redent classification puts the skippers in the superfamily Papilionoidea along with the other butterlies. It really amounts to expanding what was formerly considered a butterfly to include the skippers. Is a compact car a sedan or a SUV?   

 

QUESTIONS ABOUT BUTTERFLIES

How do male Tiger Swallowtails differ from females? 

Females tend to be larger than males. The upper side of the hind wings has a black border in both males and females, but in females, this border is also heavily dusted with blue scales. (see photographs)

Male Tiger Swallowtail
The outer edge of the hind wings has a black border.

Female Tiger Swallowtail
The black border of the hing wings has prominent blue markings.

Why are some Tiger Swallowtails largely black? 

A Tiger Swallowtail with the yellow regions of the wings replaced by dark melanin pigment.
The border of the hind wings has blue markings, so it is a female.

The dark form of the Tiger Swallowtail is due to the production of a pigment called melanin in all the wing scales that would normally be yellow. This pigment is the same as that produced by your own skin cells when exposed to sunlight. The melanistic color pattern is only found in some females. All the males sport the yellow and black tiger pattern, while females can be either melanic or yellow and black. The melanic coloration is controlled by a single gene that is expressed only in females. Males can carry this gene, but it will not be expressed. The percentage of melanistic females in a population varies from zero to > 75%. The highest number of melanic females are found in areas where another dark-colored butterfly, the Pipevine Swallowtail, is also common. In areas where the Pipevine Swallowtail is less common there are fewer melanistic Tiger Swallowtails. In the northern states the Pipevine does not occur and all the Tiger Swallowtails are black and yellow..

How does the presence or absence of Pipevine Swallowtails affect how common melanistic Tiger Swallowtails are? 

Pipevine Swallowtail caterpillars feed on plants in the Pipevine family Aristolochiaceae. These plants contain a very toxic substance, aristolochic acid, that the Pipevine caterpillar stores in its body. The toxic substance is transferred to the adult butterfly during metamorphosis, making the adult butterfly both distasteful and toxic. (This is like the Monarch butterfly, but the toxic material is different.) When naïve birds are offered a Pipevine Swallowtail to eat they swallow the butterfly and then immediately retch and vomit it up. This single experience is enough to keep a bird from eating another one, or any butterfly that resembles a Pipevine Swallowtail. (Naive birds will eat a melanic Tiger Swallowtail, but not after first eating a Pipevine Swallowtail. 

 

This similarity is an example of a type of mimicry - where a harmless or edible species gains protection from predators by resembling a distasteful or poisonous species. It is called Batesian mimicry, named after the English naturalist Henry Walter Bates who discovered it. A Batesian mimic resembles a model species that is either poisonous or distasteful or dangerous. The Batesian mimic is neither poisonous, distasteful, nor dangerous.

There is a second type of mimicry in which two or more species that are poisonous, distasteful  or dangerous resemble each other. For example, many bees are similarly colored black and yellow. This common pattern of stinging insects represent a group of insects that share painful stings and black and yellow markings. A potential predator learns from experience not to mess with an insect that resembles a yellow jacket. This kind of mimicry is named for a German naturalist: Fritz Muller - Mullerian mimicry.

 

The important thing to remember about either Batesian or Mullerian mimicry is that learning is the important factor. The predator must learn to associate a pattern with  an unpleasant outcome and then remember the association. This is especially important in Batesian mimicry. If the model becomes less common than the mimic then predators will encounter the mimic more often and may not learn to avoid species with the warning pattern. With Mullerian mimicry most of the encounters will be negative and more readily learned to avoid.

 

Why aren't all the female Tiger Swallowtails melanistic? Male Tiger Swallowtails seem to prefer to mate with the yellow and black females. (This was determined by counting the number of sperm packages in the female reproductive tract. The yellow and black females contain more sperm packages than melanistic females.) If male mating preference were the only factor, the melanistic form would eventually disappear. This is seen in the northern areas of the United States and Canada where there are no Pipevine Swallowtails. There the females are all yellow and black. But, as you move further south, in areas where Pipevine Swallowtails live, the melanistic form becomes more common. This suggests that the darker female picks up a survival advantage that compensates for her lower frequency of mating. 

 

Why don't other butterflies mimic the Pipevine Swallowtail? The short answer is that they do! In the southern US there is a mimicry complex in which a half dozen species of butterflies, including non-swallowtails, mimic the Pipevine Swallowtail. 

 

What does it take to mimic the Pipevine Swallowtail? 

Viewed from above, the Pipevine Swallowtail is black with metallic blue hind wings. The actual color of the hind wings depends on your viewing angle. The color is structural, like the colors on a DVD or CD, rather than due to a pigment. From some angles the hind wings will appear metallic green; from others, they are blue and, from still others, black. Metallic bluish green is probably the best description. The pattern of the proposed mimics is: black or dark brown front and hind wings, hind wing margin with prominent blue color. Look at the following photos and see if you would be fooled! Remember, you don't get to study the pictures, just glance at them.

Pipevine Swallowtail
The metallic blue color is structural, not a pigment.
(By Renee from Las Vegas, USA (Pipevine Swallowtail)
[CC BY 2.0  (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons)

 

The proposed mimics of the Pipevine Swallowtail found in our area are:

Eastern Tiger Swallowtail
Melanistic female

1)     Eastern Tiger Swallowtail melanistic female; black above with blue crescents on the margin of the hind wings. (See photo elsewhere in this post.)

Black Swallowtail female
Kenneth Dwain Harrelson [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0  (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons

 2)     Black Swallowtail female; mostly black above with blue crescents on the margin of the hind wings. The male Black Swallowtail lacks the blue crescents and the yellow spots on all the wings are larger.

Spicebush Swallowtail female
By Meganmccarty [Public domain], from Wikimedia Commons

3)     Spicebush Swallowtail; dark above, hind wings with greenish (male) or bluish (female) color.
 

Red-spotted Purple

4)     Red-spotted Purple; both sexes dark above and with blue border on hind wings.

 

The Batesian mimicry hypothesis has been tested with some of the above species. Florida Scrub Jays that had never seen a Pipevine Swallowtail attacked and swallowed the first one offered. They immediately retched and regurgitated the butterflies. When subsequently offered the melanistic female tiger swallowtails, spicebush swallowtails or black swallowtails, they declined to eat them. Other captive birds that had, presumably, already experienced pipevine swallowtails prior to being captured, also did not eat the offered species.
 

SUMMARY OF OBSERVED SPECIES:

Goldenrod     Solidago sp. 

Joe Pye Weed, native and ‘Little Joe’   Eutrochium fistulosum

Swamp Milkweed     Asclepias incarnata

Monarch Butterfly (adult and caterpillar)     Danaus plexippus

Oleander aphid     Aphis nerii

Large Milkweed Bug     Oncopeltus fasciatus

Sweetbay Magnolia     Magnolia virginiana

Wild Bergamot     Monarda fistulosa

Purple Coneflower     Echinacea purpurea

Eastern Carpenter Bee     Xylocopa virginica

Tadpoles     ????

Venus Flytrap     Dionaea muscipula

Horsetail     Equisetum hyemale

White-topped Sedge     Rhynchospora colorata

Colocasia ‘Blackwater     Colocasia sp.

Eastern Cottontail rabbit     Sylvilagus floridanus

Eastern Gray Squirrel     Sciurus carolinensis

Lemon Basil     Ocimum × africanum

Common Eastern Bumblebee     Bombus impatiens

Western Honeybee     Apis mellifera

Ocola Skipper     Panoquina ocola

Red Cockscomb     Celosia argentea

Dark Paper Wasp     Polistes fuscatus

Eastern Tiger Swallowtail butterfly     Papilio glaucus

Red-spotted Purple     Limenitis arthemis astyanax

Fiery Skipper            Hylephila phyleus

Hydrangea bush     Hydrangea sp.

Great Black Wasp     Sphex pensylvanicus

Carolina Anole     Anolis caroliniensis

Bristle (tachinid) Fly     Juriniopsis adusta

Luffa Gourd                  Luffa sp.

Long Handled Dipper Gourd     Lagenaria siceraria

Tobacco     Nicotiana tabacum

American Bird Grasshopper     Schistocerca americana

Cotton     Gossypium sp.

Skink     Plestiodon, probably P. fasciatus