Friday, July 22, 2016

Ramble Report July 21 2016




Today's Ramble was lead by Dale Hoyt.

Except where stated otherwise, all the photos in this post were taken by Rosemary Woodel. (Don Hunter is still indisposed. We miss you, Don! Please get well soon.)

Today's post was written by Dale Hoyt.



Eighteen Ramblers met today, which started out overcast and cool for July. Good for us but not as good for butterflies!


Today's reading: Rosemary read a poem by John Moffitt from the collection: Teaching with Fire, edited by S. M. Intrator and M. Scribner.


To Look at Any Thing

To look at any thing,
If you would know that thing,
You must look at it long:
To look at this green and say,
"I have seen spring in these
Woods," will not do - you must
Be the thing you see:
You must be the dark snakes of
Stems and ferny plumes of leaves,
You must enter in
To the small silences between
The leaves,
You must take your time
And touch the very peace
They issue from.


Today's route: We went through the formal garden in search of butterflies, pausing whenever we encountered them. In the Heritage garden we stopped to look at the great variety of insects on the Sorghum. From there we walked a short way through the Flower garden and retraced our steps back to the Conservatory.

Red Admiral butterfly: The injured tree near the Arbor was still exuding sap and attracting a variety of insects, including hornets and three Red Admiral butterflies. Red Admirals are easily recognized by the reddish-orange band on the upper side of the fore wings and the margin of the hind wings. The caterpillar feeds on nettles! It is not a rare butterfly here in the Athens area, but it is not common, either.
Red Admiral; sipping fermented sap

(Forgive the following personal anecdote; feel free to skip to the next topic.) This butterfly has a special significance for me. When I was in kindergarten I contracted rheumatic fever and was confined to bed for six weeks. The doctor told my mother that under no circumstances was I to exert myself or leave the bed, so she had to carry me to the bathroom even though she was pregnant. (In addition to being pregnant my mother was very small woman, only 4'11" and weighed 95 lbs. Today Rheumatic fever is easily treated by a round of antibiotics, but at that time bed rest was the only treatment. Penicillin had been produced was not available to the civilian population during WWII.) My brother was born in early March and soon thereafter the doctor decided that I could resume activity. But I discovered that I could no longer walk – my muscles had atrophied during the month and a half I was bed-ridden and I had forgotten how to maintain my balance – I could only crawl like a baby.

It was a beautiful March day and my father carried me outside to join my mother and new baby brother. We were sitting on the steps enjoying the sun and warmth of early spring when I noticed a butterfly on our clothes line pole. Like us, it was basking in the warmth of the springtime sun. I crawled over to the pole to get a closer look at it. It flew off, of course. I had no idea what it was then, other than a butterfly, but three years later I saw a picture of a dark butterfly with bright orange bands on its wings – the caption read: Red Admiral. Every time I see one now I am reminded of the smell of spring grass and the feeling of awe I felt on that day in March, 1944.


Ecological consequences of "prettier" flowers

Plant breeders have succeeded in producing many "improved" varieties of cutting flowers, selecting for larger and showier blooms. Take Zinnias as an example. The original form of the zinnia was like a daisy: a disk of tiny florets surrounded by a flat plane of ray florets. This was the quintessential composite "flower." The breeders succeeded in creating plants with pom-pom shaped flower heads. This transformation was achieved by converting disk florets into ray florets. The most extremely modified varieties have no disk florets, just a beautiful hemispherical cluster of ray florets. But a price is paid by this transformation. In the composite family (Asteraceae or Compositae) the ray florets with their single, strap-shaped petal (more properly called a ligule) are usually sterile, lacking both stamens and pistil. Their function is to attract pollinators, signaling the presence of nectar and pollen that is produced by the disk florets. So when the outer whorl of disk florets is converted to ray florets the total number of nectar and pollen yielding florets is decreased at the expense of doubling the "petals." The more the breeders selected for the pom-pom shaped flower the fewer fertile florets remained. The result was a flower that looked beautiful to the human eye but that gave no pollen or nectar bounty to the pollinators. A similar process occurred with the non-composite flowers. Selection for doubling the number of petals actually converts the stamens into petals. Those wonderful tea roses are mostly sterile. The moral is simple: if you want to attract butterflies to your garden you should plant the old fashioned varieties of flowers. By walking through the Botanical Garden you can see for yourself what plants are most attractive to the type of insects you want to attract.


Praying mantis. Someone spotted a cast off exoskeleton of a Praying mantis and another sharp-eyed observer found a newly molted Chinese mantis nearby. It's wings were fully expanded, but the exoskeleton was still soft and unable to afford it flight. (It takes a period of time for the exoskeleton to harden after each molt. During that time the insect is almost defenseless and unable to fly until it stiffens up.

American Dagger Moth caterpillar - best to not touch it

Butterflies


Butterflies are flying pointillist art. The beautiful and often intricate color patterns on the canvas of their wings is made of millions of tiny, flat scales, each a single color. The scales are so small that a square 1/25th of an inch on a side contains hundreds. To the human eye the individual scale is like a mote of dust, but when massed together on the planar surface of the wing they combine to produce the loveliest color patterns in the living world, each scale a single color. Like human hair and fingernails, butterfly scales are not living; each is secreted by a single cell that dies when its work is done. The resulting scale is only weakly attached to the wing surface and is easily detached. This property is useful in encounters with spider webs – the scales stick to the silk but break away, allowing the butterfly or moth to sometimes escape.


Are Butterflies and Skippers different? Some lepidopterists treat Skippers a type of butterfly (like cats are a type of carnivorous mammal). Other regard the Skippers as a distinct subgroup of the Lepidoptera: Moths, Skippers and Butterflies. The Skippers don't care.


How are Skippers and Butterflies different? Most Skippers have stout, husky bodies, i.e., their body is large in relation to the size of their wings. The butterflies have comparatively large wings for the size of their body. Skipper flight is very fast and seemingly erratic, from which the common name "skipper" is derived. The antennae are clubbed, like a butterfly's , but has a hooked projection beyond the club. (You need a hand lens to see this in most cases.)


There are several different subgroups of skippers but in our area we have to deal with just two: the grass skippers and the spread-wing skippers.

Grass skippers tend to be smaller and their caterpillars feed on grasses. When they are visiting flowers their wings are usually held together over their back, except when basking (more on basking below). 


Spread-wing skippers, as their name implies, hold their wings horizontally when they are resting or nectaring. But some of the spread-wings, like the Silver-spotted skipper, just hold their wings in a slight V-angle that may range from 90 to just a few degrees. 

Fiery skipper; typical basking pose, hind wings almost horizonal; fore wings less open.
Basking grass skippers hold their wings in a characteristic pose: both wings are held open, but the hind wings are held almost horizontally while the forewings are only slightly opened. The body is oriented so that it is maximally exposed to the sun. This enables the skipper to gain heat rapidly and keep its body temperature high enough for rapid flight.

Fiery skipper

Silver-spotted skipper; note husky body.

There were two common Skippers nectaring in the Flower garden today: Silver spotted skipper (Epargyreus clarus), which is a spread-wing skipper and a Fiery skipper (Hylephila phyleus), a grass skipper. The Silver spotted skipper is a large skipper with a prominent silver spot on the underside of the hind wings and a large orange spot on the underside of the front wings. The fiery skipper is yellowish-tan with a scattering of black dots on the underside of both wings. 

Ocola skipper (photo by Don Hunter)
Long-tailed skipper
We saw one individual each of the Ocola skipper (Panoquin ocola), a Long-tailed skipper (Urbanus proteus) and a Duskywing skipper (Katherine said it might be Horace's duskywing (Erynnis horatius).

Eastern tiger swallowtail; male - note absence of blue color on the dark border of the hind wings
The Eastern Tiger swallowtail is the state butterfly of Georgia. This large yellow butterfly with black stripes is common and very distinct. The swallowtail in the name refers to the projections from the hind wings that are reminiscent of the tail feathers of a swallow. At the base of tails there is a circular marking that, together with the swallowtail makes this area of the wing resemble a head with large eye and antennae. Predators may mistakenly attack this pseudo-head and get a mouthful of wings while the butterfly escapes, a little more ragged but still alive. At least that is the theory. In support is the frequent occurrence of damage to this part of the hind wing suggesting that predatory attacks really are misdirected.
Eastern tiger swallowtail; melanic female
The tiger stripes are still faintly visible.

There is another color form of the Eastern tiger swallowtail, one that is uniformly dark in color. This results from the presence of a dark pigment, melanin, the same substance that is produced in human skin exposed to sunlight. The yellow areas of the wing are black, obscuring the tiger stripes. (They can still be seen if the wings are back lit by the sun.) The curious thing is that these melanic forms are only found in females; the males are always the black and yellow form. In our area about 80% of the females are melanic. It is thought that the melanic females are mimicking a distasteful swallowtail, the Pipevine swallowtail, which, like the Monarch butterfly, acquires a foul taste from its larval food. Support for this idea is found in the proportion of melanic females: it is highest in the South where the Pipevine swallowtail is common. In more northern areas, where the Pipevine is rarer, the melanic tiger swallowtail is less common. And in Canada, where the Pipevine swallowtail is not found, all the tiger swallowtails are yellow with black stripes. So it appears that natural selection favors the melanic form where its model is common. This is thought to be an example of what is called Batesian mimicry. (A Batesian mimic is harmless and edible but resembles a poisonous or distasteful species and thereby gains protection from predators.) 

The puzzle is why the melanic condition is restricted to the females. Some have suggested that the yellow and black pattern is necessary for mate recognition by females, but this idea has not been tested, so far as I know.


You can distinguish tiger swallowtail sexes by the presence or absence of blue scales on the dark border of the hind wing. If it is densely blue then it is a female, otherwise it is a male.

Summer Azure butterfly

 Speaking of blue -- there was a single Azure butterfly nectaring on some of the flowers, probably a Summer Azure. The Azures are a bit unsettled at present. Some think that there may be at least five different species that differ in their food plants and flight times. Others think that is too many. But all would agree that the blue on the upper surface of the wings is like a piece of the sky.

The surprise for today was a Giant swallowtail, the largest butterfly in North America nectaring in the flower garden. The food plant for this species is citrus. If there are any planted in the garden they may have caterpillars. They also breed on a native plant species, Wafer Ash. I have only seen one of these in the garden, so we'll have to check it out also.
 
Giant swallowtail nectaring

Sorghum ecosystem

Sorghum; looks like corn but no ears in the leaf axils;
Flowers are at the top; that's where the seed appears;
Corn has tassels (male flowers) on top.

In the Heritage garden there is a row of Sorghum plants that are infested with aphids. Right now the aphid population is relatively small, but aphid populations can grow rapidly and in a few more weeks every plant will be covered with them. But you won't find them on the upper surfaces of the leaves – you'll have to lift the leaves to see them. The aphids are sucking the sweet Sorghum sap and they excrete what they don't use as a tiny droplet of what is euphemistically called "honeydew." This sweet fluid accumulates on the leaves below the aphid colonies and attracts many kinds of bees and wasps, who scurry across the leaves searching for the sweet residue.
Small aphid colony on underside of Sorghum leaf


Ladybug larva; these beetle larvae are voracious eaters of aphids

Asian multicolored lady bugs mating;
like their larvae, these beetles also eat aphids.

The attendees at these sugar parties are flies, wasps and bees. Today the party was dominated by two categories of wasps: social wasps and solitary wasps. The social wasps you're probably familiar with – yellowjackets, paper wasps, and hornets. They live in nests made of paper and form large colonies in which only one individual lays eggs, while the others perform non-reproductive tasks: foraging, nest construction and cleaning, larval feeding and colony defense.

Social wasps

Polistes carolina; a paper wasp

Another paper wasp

Another paper wasp, possibly Polistes fuscatus
Solitary wasps were by far the most abundant wasps today and we were able to recognize many distinct kinds, even though we couldn't identify them. 
 
A scoliid wasp; preys on scarab beetle (like Japanese beetles) larvae

A solitary wasp

Another solitary wasp; pretty orange legs


Yet another solitary wasp
Male honey bee (Drone); big eyes - the better to find a mate with.
(photo by Angeli Menon)

I think this one is a Mud dauber
(photo by Angeli Menon)

Two more wasps
(photo by Angeli Menon)

Solitary wasp and lady beetle (lady bug)
(photo by Angeli Menon)

Looks like a Yellowjacket, but I don't think it is.
(photo by Angeli Menon)


As the name implies, this type of wasp does not live in colonies. Each female constructs her own nest, typically a burrow in the soil or an excavation in a twig. She then searches for food for her offspring and each kind of wasp seeks a specific type of prey: crickets, spiders, grasshoppers, caterpillars, etc. Many have very narrow tastes. For example, one wasp preys only on the queen ants of one species. 

When the prey is found it is paralyzed, not killed, by the sting and then carried back to the nest where the female lays a single egg on it and closes the nest. The female wasp then repeats this process until it dies.


When the egg hatches the wasp larva feeds in darkness on the still living body of its host until it reaches the size to pupate. The pupal stage may last until the following year or there may be two or more generations in a single year. When the adult emerges from the pupa it digs its way out and starts the next generation.

That's it for today's post!



4 comments:

  1. Dale,
    Your posts are always so informative, and often witty as well. Thanks for making learning about insects and plants so enjoyable (now if I could just retain some of it in my brain). Larry

    ReplyDelete
  2. We saw limes on a bush near the steps.

    ReplyDelete
    Replies
    1. That could be what attracted the Giant Swallowtail. We'll have to look over the leaves to see if there are any caterpillars.

      Delete

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