Ramble Report July 8 2021

Leader for today's Ramble: Dale
Link to Don's Facebook album for this Ramble
Number of Ramblers today:  25
Today's emphasis:  "Seeking What We Find" on the Purple Trail.
Reading: An excerpt from: Trees: Their Natural History, 2nd ed. by Peter A. Thomas, 2014, p. 376:

The value of trees
Over their long history, trees have played an important part in our lives that goes beyond just the supply of wood. Trees have been (and still are) sacred to many peoples; oaks were sacred to the European Druids, baobabs (Adansonia digitata) to African tribes, the ginkgo (Ginkgo biloba) to the Chinese and Japanese, sequoias (Sequoiadendron giganteum) to N American first people, and monkey puzzles (Araucaria araucana) to the Pehuenche people of Chile. Indeed, many of our words and expressions are derived from a close association with trees. Writing tablets were once made from slivers of beech wood (Fagus sylvatica), and 'beech' is the Anglo-Saxon word for book. Beech is still called 'bok' in Swedish and 'beuk' in Danish. Romans crowned athletes with wreaths of the bay laurel (Laurus nobilis); this was extended to poets and scholars in Middle Ages, hence Poet Laureate. Similarly, Roman students were called bachelors from the laurel berry (baccalaureus) leaving us with bachelor degrees (baccalaureate) and, since Roman students were forbidden to marry, unmarried bachelor males.

Announcements/Interesting Things to Note:

• Emily has been in touch with Satisfactory Printing about getting a new run of the "Nature Ramblers" T-shirts last available in 2015. The design and layout would be the same ("Nature Ramblers", "Seeking What We Find", and a dragonfly), but it may be possible to have more choices of style and color. More details will follow.

• 

  Nature Ramblers T-Shirt, 2015 vintage
  2021 edition will have same design but different styles, colors.

  
  

  
   
• This morning I heard my first Katydid calling from the trees in the parking lot.
• Last Tuesday I heard the first annual or "dog-day" cicada calling from the parking lot trees.
• Jim McMinn recommended a book, American Canopy: Trees, Forests and the Making of a Nation, by Eric Rutkow. It's a history of the how the trees and forests have impacted America over the last 400 years.
  

Today's Route: Starting with the International Garden Flower Bridge and the Bottlebrush Buckeye we walked through the China and Asia section to the head of the Purple Trail, then toward the river through the first deer gate to the first Purple Trail Flower Garden spur back to the steps up to the Heritage Garden.
Today's Route:   We left the arbor and headed down the paved path to and over the Flower Bridge, moving through the China and Asia Section to the Purple Trail trailhead.  We followed the Purple Trail  down to the Purple Trail-Flower Garden Spur and took it up along the edge of the Flower Garden and to the steps leading up to the Heritage Garden.  We then made our way through Freedom Plaza and on to the back patio entrance to the Visitor Center.  Scattered groups then engaged in some post-Ramble socializing before folks headed home or out to lunch.

OBSERVATIONS:

 

Flower Bridge:

Only a few flowers remain on the Bottlebrush Buckeye.

A few Bottlebrush Buckeye fruits are starting to develop.

Bottlebrush Buckeye is for all practical purposes finished blooming. We could only find a few dozen blooms high up on the tree. Out of the thousands of flowers there are a few fruits starting to form. Almost all are on the upper reaches of the inflorescence because that is where the "perfect" (the flowers with both male and female reproductive structures) flowers were found. Buckeye fruits are large and represent a heavy investment on the part of the plant. Perhaps that is why the number of perfect flowers is so few.

China and Asia Section:

Forest Spotted Orbweaver

We are beginning to see spiders on our Rambles, probably because they have finally grown to the size that their webs have become noticeable. Most of the web building spiders are annual, i.e., the eggs overwinter in a protective silken structure, hatch in spring and the young spiders grow into maturity during the summer, dying in the fall after mating and laying eggs.  

The capture web spun by the Forest Spotted Orbweaver looks disorganized in the center, where the spider sits. I thought that it might be an early attempt by an inexperienced web builder, but scanning the photos of this species on the internet showed that all of this species build a similar messy web. Other orbweavers spin a web with a distinctively different type of silk in the center, called a stabilimentum. (Look for this in the Yellow Garden Spider web, later in this report.)

 

Purple Trail

With the bark wet from rain and dew it is difficult to see the sap wells in this section of the trunk of a Hophornbeam.

The Hophornbeam is one of the most common subcanopy trees in the Botanical Garden natural areas. And almost all of them show signs of having been visited by Yellow-bellied Sapsuckers, a type of woodpecker. The Sapsucker is a winter resident, returning north in the spring to nest and raise their young. While here they have the habit of drilling sap wells in the trunks of trees. These are a group of shallow holes spaced about 1/2 inch apart that encircle the trunk. The sap wells provide a slightly sweet drink and also attract insects that are eaten by the birds. 

The tree soon blocks the sap flow and the sapsucker has to peck a new series of holes. Their favorite trees eventually become riddled with former sap wells from top to bottom. 

It appears that no one knows how the bird selects its trees: it could be trial and error or it could be taught by observation of other birds or learned from the parents.

 

Smooth Chanterelle

Avis discovered a Chanterlle mushroom growing beneath the Hophornbeam. These fungi are cherished by cooks and gourmets.

Beech leaves have wavy edges.

 

Buds are developing at the base of leaves. By fall they will be 2-3 times as long and sharp pointed.

American Beech trees have three features that, together, make them unique among the trees in this area: leaves with wavy edges, long, pointed buds and smooth, gray bark. Those wavy edges can be remembered by this aid:"Where do you find the waves? At the beach!" Get it?

 

Beech Blight Aphids
The fluffy white material is wax secreted by the aphids.

Beech Blight Aphids are always entertaining. Disturb the branch they are feeding on and they begin to perform their boogie-woogie dance, waving their waxy adornment in the air. It is thought that this unified display might protect the colony members from attack by predators and/or parasitoids.

Here's a link to a short video that shows the "boogie woogie" aphid dance. Don also has a video recording of these aphids in his FB album (link at the start of this post.)

These aphids don't seem to do any great harm to the Beech tree. There is another organism that is dependent on them: a fungus. It grows on the sugary droppings that accumulate beneath the aphid colonies. Initially it looks like a black stain but will develop into something that looks like a black kitchen scrub pad.

Asiatic Oak Weevil

Asiatic Oak Weevil is not restricted to Oaks. They feed on other trees in the same family, Fagaceae, to which Beeches belong. The adult weevils hide in leaves that caterpillars have folded together, They feed from the leaf margin inwards.

A polypore fungus on a well rotted piece of wood.

Destroying Angel
A deadly poisonous mushroom

Don pointed out the characteristics of a deadly poisonous mushroom, the Destroying Angel. Never eat a mushroom that looks like this. Starting at the bottom, there is a bulbous swelling that is found in most Amanita mushrooms. Toward the top of the stalk is a collar-like structure called the partial veil. Above the partial veil is the cap with gills on its undersurface. The combination of these three features: gilled cap, partial veil and bulbous base means "don't eat."

An Inchworm, a caterpillar of the geometrid moth family hanging from an almost invisible silk thread.

Inchworms are almost never seen on their host plants because their shape and coloration make them look like part of the leaves they are eating or just another twig on a branch. They get their name, inchworm, from the way they walk: the rear end is brought up to the head end, making an inverted "U" shape. The claspers on the hind end then grasp the surface and the head end releases its attachment and extends forward in a straight line. It looks like the caterpillar is measuring the surface its crawling on, hence the "inchworm" common name.
In addition to resembling twigs and leaves, inchworms have another defense against being eaten: they drop off the tree they are dining on when danger threatens. Put yourself in the place of a tasty inchworm when a bird lands on your branch. If you jump you can fall out of danger. But when you hit the ground, you'll be faced with another problem - where is your food? How will you find your way back to that tasty leaf you were munching? You could wander for hours and never even find your tree trunk.
A safety line is the solution. Like most caterpillars, inchworms can produce silk from silk glands in their head. When danger threatens, they start releasing a silken safety line from these glands. The inchworm glues one end of the silk to the leaf or twig and then jumps off. The weight of the caterpillar pulls the silk out of the gland as the caterpillar falls. It happens fast enough to fool a bird! Not only has the caterpillar escaped its predator, it has a way to return home - climb up the silken thread. I have watched inchworms climbing their safety lines and can tell you that it involves winding the thread up into a wad held by their thoracic legs, but I can't provide any more details. Perhaps Ramblers with more acute vision can find the answer.

An earthworm, possibly a non-native.

Earthworms are difficult to identify. I initially thought that the one in the photo above might be a Crazy Worm (AKA Snake Worm, Jumping Worm). The problem with that ID is that it lacks a key character: a white ring around the body. This individual lacks that white ring, but it may just be immature. Crazy Worms can reach a length of 8 inches and, when held, feel very muscular, as though you were holding a snake, not a worm. I just don't know enough to be very confident of that ID, so I'm avoiding it.

The Invasive Worm problem. Several Ramblers had heard of invasive worms causing damage to ecosystems and wondered if they were a problem here. The problem was first noticed in the parts of the country that had been covered by glaciers until 11-12 thousand years ago. These glaciated regions had no native earthworms. Thousands of years covered by ice miles deep exterminated all the earth worms in the soil underlying the ice. When the climate warmed and the glaciers retreated the newly exposed areas were earthworm free. Ecosystems gradually developed in these now ice-free areas. Mosses and ferns could colonize these areas with their spores that could be carried by the wind. Seed plants were not as easily dispersed but arrived, dispersed by winds and animals from the unglaciated areas. Earthworms are confined to the soil and are not easily dispersed, so the ecosystems of the glaciated areas developed without them in the soil. This meant that the organic matter in these soils decayed more slowly and, therefore, accumulated more than it would have in the presence of earthworms. The soils developed a deep duff layer of slowly decaying organic material and the plants adapted to these conditions.
Then came European man who introduced worms adapted to thousands of years of agricultural practice.
Many of the worms introduced were surface feeders and began to feed on the deep layers of duff that had developed. This caused a decline in the spring ephemerals, shrubs and trees that were adapted to the rich layer of duff.
This pattern was first seen in Minnesota and is now happening in the New England states.
The situation in unglaciated areas is not as clear or as well studied. These areas never lost their native earthworms so the invaders had to deal with established native species. In addition, earthworms disperse slowly; it takes many years for them to move a few hundred feet unless assisted by human activity.

 

Flower Garden:

Oak Apple Gall cut in half to show interior.

An Oak Apple Gall is produced when a small wasp lays an egg in the middle of an Oak leaf. The leaf responds by producing a spherical swelling about the size of a golf ball. But the swelling contains additional tissue in the center, suspended by fibers that run from the center to outer edge of the gall. The central matter is where the larval gall wasp feeds on the gall tissue. The central location is thought to provide protection against parasitic wasps who would lay an egg on the larval wasp. It would prevent parasites with short egg laying tubes from reaching the center of the gall.

Five-lined Skink

There are three species of Five-lined Skinks in our area; this is most likely the Common Five-lined Skink. At hatching all of them have five yellow stripes that run the length of the body and a bright, blue tail. As they age the stripes and blue tail get duller and duller until body and tail are a uniform shade of gray-brown.

Blackberry Lily with Honey Bee

Indian Pinks

Yellow Garden Spider
The stabilimentum is the conspicuous stretch of zig-zag silk that runs vertically with the spider sitting in the middle.

Yellow Garden Spiders, like many other orb weaving spiders, produce a structure on their webs called a stablilimentum. Many ideas about the function of the stabilimentum have been proposed, but were hard to test. One hypothesis with experimental support is web damage prevention idea. The stabilimentum makes the web more visible and prevents birds from flying into the web and destroying it. This idea was tested in Florida. The investigators located 60 webs built by a kind of spider that builds a web at night and takes it down at dawn, rebuilding it the following night. By removing the spiders from each of the 60 webs at 2AM they had a set of webs that were unoccupied the following morning. Thirty of these were control webs and the other 30 had an artificial stabilimentum made of paper attached. They examined all the webs at 2hr intervals, starting at 6AM, and recorded whether the web was intact or damaged. The pattern was clear: by 8AM 60% of the unmodified webs had been damaged vs. only 20% of the artificial stabilimentum webs. By noon 93% of the control webs were damaged but only 40% of those with artificial stabilimenta.

These results are consistent with the idea that the stabilimenum reduces damage to the web.

Long-legged Fly
Predators on other insects (aphids, springtails, mites, flies) in both larval and adult stages.

Furrow bee visiting Gazania (AKA African Daisy) flower.

 

Summary of Species Observed

 

Bottlebrush Buckeye                 Aesculus parviflora
Asian Green Dragon                  ??
Forest Spotted Orbweaver        Neoscona domiciliorum
False Cypress                           Chamaeciparis sp
Hophornbeam                           Ostrya virginiana
Smooth Chanterelle                  Cantharellus lateritius
American Beech                        Fagus grandifolia
Beech Blight Aphid                    Grylloprociphilus imbricator
Asiatic Oak Weevil                    Cyrtepistomus castaneus
White Cheese Polypore            Order Polyporales
Destroying Angel                      Amanita bisporigera
Geometer moth caterpillar        Lepidoptera: Geometridae
Deciduous Holly                       Ilex decidua
Asian earthworm                      ??
Blackberry Lilies                       Iris domestica
European Honey Bee              Apis mellifera
Indian Pink                               Spigelia marilandica
Amaryllis                                  Amaryllis sp.?
Yellow Garden Spider              Argiope aurantia
Long-legged fly                        Diptera: Dolichopodidae

Gazania                                   Gazania sp
Furrow bee                              Halictus sp.
Five-lined Skink                       Plestiodon fasciatus
Mountain Mint                         Pycnanthemum sp.