Nature Ramble Report for June 9, 2022
Leader for today's Ramble: Dale
Authors of today’s report: Linda and Dale
Leader for today's Ramble: Dale
Authors of today’s report: Linda and Dale
Link to Don's Facebook post for this Ramble All the photos that appear in this
report, unless otherwise credited, were taken by Don Hunter.
Today's emphasis: The Yucca plants in the Dunson Native Flora Garden, wildflowers in the right-of-way, and further discoveries in the Dunson Native Flora Garden.
Reading: Don read from “A Long Island Meadow,” a chapter in Frances Theodora Parsons’ According to Season, published in 1902.
“The brilliant coloring which is a feature of this midsummer meadow is intensified by the insect life which it sustains. Butterflies, especially, seem to abound. They float over the nodding grasses or poise quivering above a nectar-laden blossom or rest on some leafy plant, the dull undersides of their folded wings blending with their surroundings and diminishing the likelihood of attacks from their enemies.
Not only is a butterfly endowed with unusual beauty, but its life-history is full of charm. Then, too, the very names of butterflies breathe romance (unlike those of birds and plants, of which “Wilson’s thrush” and “Clayton’s fern” form fair samples). Who would not yield to the spell of the Wanderer, the Brown Elfin, the Little Wood Satyr, and the Dreamy Dusky-wing? Or who could resist the charm of the Painted Lady, the Silver-spotted Hesperid, the Tawny Emperor, or the Red Admiral?
In the meadow, perhaps, the monarch or milkweed butterfly is one of the most omnipresent. Indeed, this is probably the best-known butterfly in the United States, as its broad, orange-red, black-bordered wings carry it many hundreds of miles and make it conspicuous everywhere. In addition to being the most widely distributed, it is one of the most interesting of our butterflies. Its career is an amazing one. How so fragile a creature can endure the fatigue and resist the storm and stress incidental to a journey of thousands of miles, such as it is believed to take when migrating to southern lands, and how such a “shining mark” escapes destruction from its enemies, it is difficult to understand. That this annual migration does take place seems fairly well established. The butterfly is known to have marvelous powers of flight, and along the coast in fall it has frequently been seen assembling in flocks numbering hundreds of thousands, changing the color of the trees on which it alights for the night.”
Show-and-Tell:
“The brilliant coloring which is a feature of this midsummer meadow is intensified by the insect life which it sustains. Butterflies, especially, seem to abound. They float over the nodding grasses or poise quivering above a nectar-laden blossom or rest on some leafy plant, the dull undersides of their folded wings blending with their surroundings and diminishing the likelihood of attacks from their enemies.
Not only is a butterfly endowed with unusual beauty, but its life-history is full of charm. Then, too, the very names of butterflies breathe romance (unlike those of birds and plants, of which “Wilson’s thrush” and “Clayton’s fern” form fair samples). Who would not yield to the spell of the Wanderer, the Brown Elfin, the Little Wood Satyr, and the Dreamy Dusky-wing? Or who could resist the charm of the Painted Lady, the Silver-spotted Hesperid, the Tawny Emperor, or the Red Admiral?
In the meadow, perhaps, the monarch or milkweed butterfly is one of the most omnipresent. Indeed, this is probably the best-known butterfly in the United States, as its broad, orange-red, black-bordered wings carry it many hundreds of miles and make it conspicuous everywhere. In addition to being the most widely distributed, it is one of the most interesting of our butterflies. Its career is an amazing one. How so fragile a creature can endure the fatigue and resist the storm and stress incidental to a journey of thousands of miles, such as it is believed to take when migrating to southern lands, and how such a “shining mark” escapes destruction from its enemies, it is difficult to understand. That this annual migration does take place seems fairly well established. The butterfly is known to have marvelous powers of flight, and along the coast in fall it has frequently been seen assembling in flocks numbering hundreds of thousands, changing the color of the trees on which it alights for the night.”
Show-and-Tell:
Gary brought some filamentous algae he collected from the water feature behind the Porcelain Arts Museum. Looks can be deceiving: the swaying masses of algae in the pool looked slimy but actually have a texture more like cotton candy.
Bill dissected a fresh Oak Apple Gall, exposing the larval Cynipid wasp in the fibrous mass suspended inside the gall. The gall formed when a female Cynipid wasp injected an egg into a vein of a developing leaf, hijacking the process of leaf development. Instead of producing a leaf, the plant responded to the invasion by forming a structure around the egg, both isolating and protecting it. The egg hatches into a larva then a pupa and ultimately into an adult wasp that chews its way out of the gall and takes flight. The gall doesn’t always succeed in protecting its larval resident however; birds such as woodpeckers and chickadees have learned to open galls to reach the snack that is captive inside.
Today's Route: We left the Children’s Garden pergola and took the entrance road to the lower end of the Dunson Native Flora Garden. We visited the Yucca patch, then the adjacent right-of-way, and returned to the Children’s Garden by way of the Dunson Garden and Shade Garden paths.
OBSERVATIONS ON TODAY'S RAMBLE
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| The
paved walkway to the Children’s Garden is lined with Southern Magnolias, whose flowers are among the most dramatically beautiful in the world. |
Adventures in the Yucca patch...
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| A storm-battered Yucca flower with central pistil (the ovary is green) and six stamens |
At the lower end of the Dunson Garden, near the sunny edge of the right-of-way, there is a group of Yucca plants past peak bloom, the nearly spent flowers suffering from a beating they took in last night’s thunderstorm. Yucca flowers look like typical flowers, with a central pistil composed of an ovary, a style, and a stigma, all of which surrounded by a whorl of stamens producing pollen at their tips. But if you look closely, the stigma – the sticky surface that receives pollen – is not really apparent. In fact, it is tucked down inside a depression at the top of the style. Why would a flower hide its all-important stigma from potential pollinators? As it turns out, yuccas have a special relationship with a group of pollinators – yucca moths – that revolves around the hidden stigma.
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| Yucca moth |
During the day, yucca moths find shelter among the yucca flowers – shaking the stem of the flower cluster flushes them out. The moths that fly out are small, inconspicuous, silvery-gray insects that are so short-lived they do not even eat. So, what makes them so special? When night falls, the female moth flies from her shelter and begins gathering pollen from the yucca flowers. She rolls the pollen into a ball, tucks the ball under her chin, and flies to a flower on another plant. Using tentacle-like mouth parts found only in yucca moths, she tamps the pollen ball into the depression at the top of the style where the stigma is located. When she finishes tucking the pollen into the stigma, she walks to the bottom of the pistil and inserts a number of eggs into the wall of the ovary – eggs that will develop into larvae (caterpillars) inside the ovary. In a sense, she is farming yucca seeds to feed her young. The pollen she tucked down into the stigma germinates, sending a pollen tube down the style and into the ovary, where sperm are released and united with an ovule to begin the process of seed formation. If the female moth has done her job properly, there will be more than enough developing seeds to feed all her caterpillars, with some left over to perpetuate the yucca.
But what if she lays too many eggs? Or another moth chooses to lay eggs in the same ovary? This is where the plant gets to "decide" what happens. It can somehow sense when the load of caterpillars is too great for its seeds to survive. Then the plant aborts the blossom, reserving its resources for other flowers that will be able to produce an adequate number of viable seeds. Researchers have examined aborted flowers and found multiple ovipositing scars on their ovaries, showing that the moths often lay more eggs that a single blossom can support.
When the caterpillars mature, they eat their way out of the ovary and crawl into the leaf litter on the ground below the plant and construct a cocoon. Moths from some of these will emerge the following spring, but others cocoons can remain dormant for several years. One entomologist had a cocoon in a jar on his desk for over 10 years before a moth emerged.
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| Yucca Moth Caterpillar photo by Andy Reago and Chrissy McClarren, Flickr |
This is a matter of critical timing. The moths have a short life span and they must emerge while the yuccas are flowering. If they emerge too early, they may die before the yucca blooms; too late, and they will not find any flowers to pollinate and oviposit in. How the plant and the insect are synchronized is currently unknown.
There is one more wrinkle in this system of checks and balances – cheating moths. There are several species of yucca moths that lack the special tentacle of the mutualist yucca moth. These moths can't and don't pollinate yucca flowers, they just lay their eggs in them, taking advantage of the efforts of other, pollinating, moth species. They are free-loaders, parasites on a mutualistic relationship.
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| Eastern Leaf-footed Bugs are swarming all the Yucca plants. |
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| Eastern Leaf-footed Bug adult and nymph |
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| Rattlesnake Master (Eryngium yuccifolium) is not a yucca but the resemblance is reflected in the species name – yuccifolium – “yucca leaf.” |
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| The flower heads of Rattlesnake
Master are unique in the Carrot family. Shown here are immature heads that will expand into round, sputnik-like clusters. |
Late spring wildflowers are abundant now in the right-of-way….
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| American Wisteria |
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| Wild Petunia |
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| Small's Ragwort |
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| Narrow-leaved Sundrops |
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| Hairy Cat’s Ear, an invasive newcomer to our spring flora |
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| In a case that seems a lot like natural justice, Eriophyid mites invade Poison
Ivy leaves, creating galls that resemble the pustules that PI inflicts on its victims. Photo by Bill Sheehan. |
Two bottomland tree species, Green Ash and Box Elder, have opposite and compound leaves and produce winged seeds called samaras. Their bark is similar too but their leaflets differ.
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| Green Ash leaflets have smooth margins. |
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| Box Elder leaflets have toothed margins. |
Maryland Wild Senna, which blooms later in the summer, is found in drier and sunnier portions of the Garden’s floodplain forest. We were initially confused about its identity in this immature stage but several features are diagnostic even now: large compound leaves with smooth-margined leaflets, leaves with stipules at the base (at this stage they resemble thorns), and one or two nectar glands on each leaf stalk. Ants and small flies and bees gather nectar from the glands. Maryland Wild Senna is a larval host plant for several species of sulphur butterfly as well as silver spotted skippers.
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| Maryland Wild Senna |
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| Maryland Wild Senna with narrow, pointed stipules at the base of the leaves and round nectar glands on the leaf stalks |
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| This smooth, green caterpillar was seen on a Yellow
Crownbeard stem. ID unknown, possibly Green Cloverworm (thanks, Avis!). Silvery Checkerspot caterpillars, which are known to use this species as a host plant, look very different. |
From the floodplain, our return journey took us through Dunson Garden where a number of plants are in fruit or flower.
SUMMARY OF OBSERVATIONS:
Southern Magnolia Magnolia grandiflora
American Nursey Spider Pisaurina mira
Curly-leaf Yucca Yucca filamentosa
Spanish Bayonet Yucca aloifolia
Eastern Leaf-footed Bug (adult and nymph) Leptoglossus phyllopus
Spotted Cucumber Beetle Diabrotica undecimpunctata
Rattlesnake Master Eryngium yuccifolium
American Wisteria Wisteria frutescens
Small’s Ragwort Packera anonyma
Hairy Cat’s Ear Hypochaeris radicata
Narrow-leaved Sundrops Oenothera fruticosa
Wild Petunia Ruellia caroliniensis
Loblolly Pine Pinus taeda
Poison Ivy Toxicodendron radicans
Eriophyid mite Aculops rhois
Trumpet Vine Campsis radicans
Green Ash Fraxinus pennsylvanica
Box Elder Acer negundo
Maryland Senna Senna marilandica
Green caterpillar possibly Green Cloverworm, Hypena scabra
Yellow Crownbeard Verbesina occidentalis
Basswood Tilia americana
Fly Poison Amianthium muscitoxicum
Goldenseal Hydrastis canadensis
Black Cohosh Actaea racemosa
Green Lacewing (larva) Chrysoperla rufilabris
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| Goldenseal fruits resemble raspberries. |
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| Fly Poison's flowers start out white and turn green with age. |
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| Black Cohosh flower spikes light up the understory like candles. |
SUMMARY OF OBSERVATIONS:
Southern Magnolia Magnolia grandiflora
American Nursey Spider Pisaurina mira
Curly-leaf Yucca Yucca filamentosa
Spanish Bayonet Yucca aloifolia
Eastern Leaf-footed Bug (adult and nymph) Leptoglossus phyllopus
Spotted Cucumber Beetle Diabrotica undecimpunctata
Rattlesnake Master Eryngium yuccifolium
American Wisteria Wisteria frutescens
Small’s Ragwort Packera anonyma
Hairy Cat’s Ear Hypochaeris radicata
Narrow-leaved Sundrops Oenothera fruticosa
Wild Petunia Ruellia caroliniensis
Loblolly Pine Pinus taeda
Poison Ivy Toxicodendron radicans
Eriophyid mite Aculops rhois
Trumpet Vine Campsis radicans
Green Ash Fraxinus pennsylvanica
Box Elder Acer negundo
Maryland Senna Senna marilandica
Green caterpillar possibly Green Cloverworm, Hypena scabra
Yellow Crownbeard Verbesina occidentalis
Basswood Tilia americana
Fly Poison Amianthium muscitoxicum
Goldenseal Hydrastis canadensis
Black Cohosh Actaea racemosa
Green Lacewing (larva) Chrysoperla rufilabris
