Today's Ramble was led by Linda Chafin.
Here's the link
to Don's Facebook album for today's Ramble. (All the photos in this post are
compliments of Don, unless otherwise credited.)
Today's post was written by Linda Chafin and Dale Hoyt.
28 Ramblers met today.
Today's reading:
No reading today.
Today's
Route: Through the Visitor Center and out the back,
then through the Herb and Physic Gardens, taking the back path past the Paw Paw
patch and across the Heritage Garden.
From there we went down the steps into the Flower Garden, making our way
to the bottom and then to the left and up the far side paths back to the
Visitor Center where we enjoyed refreshments and conversation at the Café
Botanica. Some remained for the monthly meeting of the Nature Ramblers book
group.
OBSERVATIONS:
OBSERVATIONS:
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| A small Pawpaw fruit. (click to enlarge) |
The Pawpaw Patch, planted along the path leading into the Heritage Garden, is bearing a number of fruits. Large fruits such as Pawpaw's are thought to be relicts of a time when now-extinct megafauna, large animals such as Giant Ground Sloths, American Camels, and American Mastodons, inhabited North America. The populations of plants they fed on have since shrunk and become fragmented, possibly due to the loss of their megafaunal seed dispersers. Fruits of these plants have a suite of similar characters: they can be eaten in one gulp rather than in small chunks; they are indehiscent, that is, they don't open to spread their seed; and, their hard seeds are not destroyed by chewing but require scarification to germinate. Some other large-fruited examples are Osage Orange, Honey Locust, and Avocado. Another trait these plants share is that they are now found mostly in floodplains and bottomlands, though they thrive when planted in uplands. Since they are now dependent on gravity and flowing water to disperse their seeds, they are rarely found in uplands. This is certainly the case with Tall Pawpaw.
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| Sorghum seed head (click to enlarge) |
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Sorghum seeds. (click to enlarge) |
Sorghum is flowering and fruiting profusely in the
Heritage Garden. This tall grass is native to Africa where it has long been a
staple food known as milo, millet, and durra. It is now grown world-wide –
according to Wikipedia, the worldwide are planted in Sorghum has increased 66%
in the last 50 years. The tiny fruits are cooked and eaten in stews or salads,
or ground to make flour for flatbread. They are also fed to animals. In the
U.S., the stalks are pressed for the sweet sap, which is boiled down into
sorghum syrup, sometimes called erroneously “sorghum molasses.” Sorghum plants
are very efficient users of water, employing a type of photosynthesis called
“C4” which uses only a third of the water that “C3” plants use.
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| Sorghum prop roots. (click to enlarge) |
Sorghum, like corn, sugar cane, and many other plants, have prop or buttress roots which stabilize the tall stems. They are secondary, adventitious roots that develop from nodes on the base of the stem.
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Asian Multicolored Lady Beetle (?) on Sorghum. (click to enlarge) |
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Asian Multicolored Lady Beetle pupa on Sorghum. (click to enlarge) |
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The fruit of a Brown Turkey Fig bush. (click to enlarge) |
“Brown Turkey” figs are beginning to ripen in the
Heritage Garden – and they look for all
the world like solitary fruits. But the story is a lot more complicated and
interesting than that – it’s a story about coevolution. What appears to be a
fruit is actually a cluster of tiny flowers held inside the fleshy, bulbous tip
of a short stem that has a single, minute opening at the end. These tiny
flowers release an aroma that attracts a Fig Wasp queen. She squeezes through the
opening, losing her wings and antenna in the process, but no matter–she has
just about reached the end of her life and will never fly again. Once inside,
she lays her eggs – eggs that were fertilized by a fellow (male) wasp while she
was still inside the fig where they were born. While in the process of laying
eggs, she spreads pollen around on the tiny flowers; this is pollen that she
had picked up while exiting her natal fig. Her life’s work now done, she dies
inside the developing fig. Her eggs develop into larvae that feed on the seeds
of the tiny flowers that she inadvertently pollinated; plenty of seeds are left
unharmed to fully mature. And the larvae develop into adults–the males copulate
with females inside the fig then die; the females emerge from the fig and set
off in search of another fig where they can lay their eggs. Having shared this
fascinating story, I have to break some sad news: ‘Brown Turkey’ figs were bred
to have no need for pollination! No wasps actually enter these “fruits,” which
produce seeds parthnogenetically. This is good news for vegetarians, sad news
for naturalists who like to marvel at mutualistic plant-animal interactions.
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| Brown Turkey fig interior showing
the immature flowers inside; these will develop without pollination to produce
seeds. (click to enlarge) |
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| Creeping Fig vine growing on wall
in the Heritage Garden. Its aerial roots exude a latex that hardens onto the
wall or other support, allowing the branches to stick to this surface.. (click to enlarge) |
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| Bumblebees and a Red-banded
Hairstreak visited the flowers of a True Indigo plant. This plant is used to
create an intense dark blue dye. (click to enlarge) |
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Pomegranate fruit. (click to enlarge) |
Pomegranate fruits are developing. The variety in the
Heritage Garden, ‘Eight Ball,’ has dark reddish-black fruits. Pomegranates we
see in the grocery store are usually red. Pomegranates were originally found
from Iran to India and has been grown for thousands of years. The name derives
from Latin “pomum” (apple) and “granatum” (seeded). If you look closely at a
Pomegranate flower, you’ll see that the calyx (the whorl of usually green,
leafy structures below flower petals) is tough, leathery, and red in
Pomegranates. After the flower is pollinated, the seeds in the ovary swell and
fill out the base of the calyx, which enlarges into the rounded fruit we
recognize.
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Remains of pomegranate flowers. (click to enlarge) |
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| Individual Pomegranate seeds are each
enclosed inside a fleshy, juicy aril derived from the seed’s coats. (click to enlarge) |
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Squirrels apparently don't like unripe pears. (click to enlarge) |
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| A Paper Wasp nest (Polistes carolina). Some of the cells are capped - these contain pupae that haven't emerged yet. (photo by Dale Hoyt) (click to enlarge) |
Nest building begins anew each spring. Old nests are not
reused. An overwintering wasp that mated the previous fall begins her nest by
herself or with the company of one or two of her sisters. If a single female
starts the nest she must do everything: gather wood pulp, build the first cell,
lay an egg in the cell, forage for caterpillars to feed to the larval wasp
after the egg hatches, add new cells to the growing next, extend the height of
existing cells to keep pace with the growth of the larval wasps. It’s an
enormous task for a single female and many of the nests started by single wasps
do not survive. Those begun by a group of wasps can grow faster and a division
of labor soon develops in them. One of the fertilized wasps becomes the “queen”
whose primary duty is egg laying. The other females become workers – their
ovaries atrophy and they become sterile. The workers forage for food, perform
nest construction, feed the larvae and defend the nest.
The size the colony reaches depends on the initial number
of foundresses. By autumn nests can vary from 100 to approximately 400 wasps.
In autumn the colony produces males and unmated females
who will become the following years queens. After mating the newly fertilized
queens seek out sheltered locations and become dormant until the following
spring.
Factoids about paper wasps:
1.
The queen (the reproductive wasp) determines the
sex of her offspring: a fertilized egg develops into a sterile, worker female.
An unfertilized egg develops into a male. Early in the season the queen lays
only fertilized eggs. Toward the end of summer she begins to lay unfertilized
eggs to produce males.
2.
The pattern of yellow marks on the face of the
wasps are highly variable, making it possible for nest mates to recognize each
other. Not only do they recognize nest mates, they recognize different
individuals in their nest. A pecking order (social hierarchy) develops within a
nest, something that is only possible with individual recognition. The pecking
order can be changed by artificially altering the pattern of facial marks.
3.
All the workers and male wasps die at the end of
the season. Only the fertilized future queens survive the winter.
4.
Old nests are not reused, each year new nests
are constructed.
The thread-like waist: The connection between the
thorax and abdomen is very narrow in paper wasps, yet it has to be large enough
for the nerve cord, the digestive tract, and circulatory vessels to pass
through to the abdomen. This means that only microscopic food particles and
soluble materials can enter the abdomen. So wasps (as well as ants and bees) can’t
eat solid food. They must subsist on a liquid diet like nectar. Where do they
get their protein? Wasps, unlike bees, are carnivores. They hunt other insects,
especially caterpillars. A captured caterpillar is chewed up into a caterpillar
hamburger that is fed to the wasp larvae. Then, when an adult wasp taps on a
fat, well fed larva, the larva emits a droplet of saliva that is rich in
protein for the adult to eat. The adult wasp and the larvae are mutually
dependent on one another. The adult feeds the larva, the larva digests the
food, uses the digestive products to grow and to make saliva, and feeds the
saliva to the adult. James Hunt, the author of The Evolution of Social Wasps,
suggests that this interdependency of adult and larva underlies the evolution
of extreme sociality in the ants, bees and wasps.
Other wasps with paper nests: There are three
other kinds of wasps in our area that build paper nests that are more complex
than the paper wasps discussed above. These are: Yellow jackets (several
kinds), Bald-faced hornets and European hornets.
All three build a paper nest similar to the nest of paper
wasps, but on steroids. It looks like two or three paper wasp nests stacked one
on top of the other and side by side on the same level.
This type of nest is built underground by Yellow jackets,
in a tree branch with a football-sized paper covering that encloses the
multi-level nests, or inside a hollow tree by European hornets.
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A Flower fly (family Syrphidae) that is a bee mimic. (click to enlarge) |
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Fiery Skipper on Lantana. (click to enlarge) |
Lantana and Fiery Skipper: Notice that the flowers
in each Lantana flowering head are two different colors: purple and yellow. As
the flower ages its color changes from yellow to purple.
When the flowers open they are yellow and after they have been pollinated
they change color to purple. A pollinated flower stops producing nectar, so the
yellow-purple color difference indicates which flower is worth visiting. But
you have to be smart enough to learn the difference. The butterflies that visit
the Lantana are up to the task. While we watched Fiery Skippers visiting the
flower heads each one would extend its proboscis into a yellow colored flower.
When finished it moved on to the next yellow flower, ignoring the purple ones.
After the last yellow flower was visited the skipper flew to another flower
head.
Martha Weiss, now at Georgetown University, showed that butterflies
could learn to identify the flowers with the nectar reward after only two days
of experience. She also surveyed the flowering plants and found that color
changing flowers were found in 77 different plant families, so it is not an
uncommon occurrence.
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Green Lynx spider well camouflaged among the leaves. (click to enlarge) |
Green Lynx spider: This spider is commonly found
lurking among the leaves in flower beds, where it is well camouflaged. Like the
Jumping spiders, it does not spin a web. But it is not an active seeker of
prey. Instead it sits and waits and when an insect happens to come nearby it
rushes over the leaves and captures it.
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| Next to
the lantanas is a bed of non-native hibiscus, their pink flowers with dark red nectar guides at the base and pure white
reproductive structures and pollen. (click to enlarge) |
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Great Blue Skimmer Dragonfly (click to enlarge) |
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Slaty Skimmer Dragonfly (click to enlarge) |
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Several large Eastern Carpenter Bees were seen feeding on nectaries at the base of the staminal tube.(click to enlarge) |
Scarlet Hibiscus is one of the most dramatically
beautiful of our native plants, its brilliant red flowers 5-8 inches wide. It
occurs naturally only in Coastal Plain wetlands but seems to thrive wherever
planted. The flowers are pollinated by bees and butterflies. Hibiscus flowers
are easily identified by the presence of a forward-projecting tube formed by
fusion of the staminal filaments. The styles and stigmas emerge from the top of
the tube.
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The caterpillar of the Virginia Tiger moth in Fringed Bluestar. This species feeds on a variety of plants. (click to enlarge) |
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Leaf-footed bug on millet seed heads. (click to enlarge) |
We've seen many Leaf-footed bugs this year, nearly always on the fruits of many kinds of plants. Where there are succulent young seeds the Leaf-foots are bound to be nearby. You should remember what they do: suck out the nutrients in the seeds, using their piercing, sucking mouthparts, a characteristic of the insect order Hemiptera. If you think about it, they are no different than us, except in the way they get their food. We eat the most nutritious parts of the plants, just like them: corn, beans, rice, wheat; we just chew instead of suck.
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A female Bold Jumper (Phidippus audax) on a millet seed head. (click to enlarge) |
Bold Jumper spider: Jumping spiders (family
Salticidae, salticids for short) have real personalities – you look at them and
they look back at you. No kidding. Like most spiders they have eight eyes, the
central pair on the front of the head are very large and directed forward,
giving them the appearance of having a face. That pair of eyes endows them with
excellent 3-D vision, greatly facilitating their hunting life style. Salticids
are visual predators, actively stalking their prey. They creep up until they
are within striking distance and then jump on the victim. Their 3-D vision
enables them to determine how far away their prey is, and adjust the power of
their jump accordingly. The distance a salticid can jump varies with the size
of the spider; some can jump as far as 50 times the length of their body. They
have silk glands at the end of their abdomen, but do not make capture webs. As
they move about they produce a single silk thread, a drag line, that functions
as a safety line. If they miss their target, or misjudge a jump, they climb
back up the silken thread to their previous location. They also use their silk
glands to build a retreat where they periodically molt their exoskeleton. The
retreat is also used by females to lay their eggs. The spider stays with the
eggs until they hatch.
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A stink bug on millet seed head (click to enlarge) |
SUMMARY
OF OBSERVED SPECIES:
Paw
Paw
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Asimina triloba
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Sorghum
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Sorghum bicolor
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Asian
Lady Beetle
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Harmonia axyridis
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Common
Fig
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Ficus carica
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Creeping
Fig
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Ficus pumila
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True
Indigo
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Indigofera tinctoria
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Bumblebee
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Bombus sp.
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Red-banded
Hairstreak
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Calycopis cecrops
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‘Eight
Ball’ Pomegranate
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Punica granatum ‘Eight Ball’
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Paper
Wasp
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Polistes
sp.
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Pear
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Pyrus
sp.
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Lantana
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Lantana
sp.
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Fiery
Skipper
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Hylephila phyleus
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Green
Lynx Spider
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Peucetia viridans
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Hairy-fruited
Hibiscus
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Hibiscus lasiocarpos
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Scarlet
Rosemallow
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Hibiscus coccineus
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Eastern
Carpenter Bee
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Xylocopa virginica
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Great
Blue Skimmer
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Libellula vibrans
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Slaty
Skimmer
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Libellula incesta
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Virginia
Tiger Moth (caterpillar)
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Spilosoma virginica
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Eastern
Leaf-footed Bug
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Leptoglossus phyllopus
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Shield
Bug (Stink Bug)
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Family
Pentatomidae
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Bold
Jumper Spider
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Phidippus audax
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