We started
today with an announcement: Emily and Dale will lead a walk at 9:00 AM next
Tuesday, Sept. 3, 2013, at Sandy Creek Nature Center. Everyone is welcome to
attend. This is the first of a monthly series of walks at the Nature Center.
Emily plans to have them on the first Tuesday of each month.
We had
three readings today; Hugh read an excerpt from Sean Beeching's book, I Like You But What Can You Do Can
You Be A Bird, pp. 45-46.
Inland is a low forest of oaks and gums, holly
and willow, the floor is mud, muddy roots and soggy leaves, it is composed of
low mounds and water-filled hollows, and it is dark, even in winter, under the
live oak leaves. The history of the
Ohoopee's past wanderings is here, these are the old channels and banks, oxbows
and meanders, I suppose, but it is too confused and too dim to be read by
me. The two great trees here are live
oak on the banks and cypress in the swamps.
Both are covered with the other great player in the coastal
landscape: Spanish moss. Does this bromeliad cast (a) spell of
lethargy over the South? Fully developed
on a big oak, ancient, shaggy, overextended. it billows in the breeze,
supported not by its own efforts but by the oak, dormant as often as not. Should some fall, so what? There's plenty more. Perhaps it exudes a substance, Tillandsiadol,
an invisible elixir that seeps into the minds of Southerners, that makes them
say, "Aw, it's alright," whether it is or not, and makes them think
that living is work enough. If this
potion could be bottled I would carry it on my back and breathe it straight
through a tube.
Dale read a
piece about scientific names from Alpine
Plants of the Northwest Wyoming to Alaska, p. 12:
If we
can no longer argue for scientific names on the basis of stability, we can
still make an argument for clarity. After all, even after scientific names
change, there is still only one official scientific name-the new one. (Numerous
common names usually remain.) You can also learn scientific names to impress
people, around the barbeque or at other social gatherings. Inexplicably to
some, Carla Bruni married former French president Nicolas Sarkozy. She
explained that, after a courtship stroll in the Elysee Palace gardens, it
struck her that "He knows all the Latin names, all these details about
tulips and roses. I said to myself, 'My God, I must marry this man.'"
Terry read
a wonderful poem by Janisse Ray:
Butterfly
Where does its fire go
when a monarch dies?
Does it vanish
in smoke,
or turn suddenly to rain?
Does it lay dead
against a mountainside
transforming placidly
to dirt,
which will harbor in its richness
millions of small burning ships
sailing a deep-green forest,
never to be seen?
Or does the fire seep
into the ground,
running in rivulets
toward the blazing core
of the earth,
one day to return:
a volcano spewing wings?
The subject
of today's ramble was butterflies. Dale began with a few comments about books and
equipment useful for learning about Georgia butterflies.
1. Minno, Mark C. 2013. Butterflies of
North Carolina, South Carolina & Georgia: A Guide to Common and Notable
Species.
This waterproof folded pamphlet guide illustrates over 80 species of butterflies and most of their caterpillars found in North Carolina, South Carolina , and Georgia. It features color photos in a side-by-side format that makes it ideal for field use. Common and scientific names, adult size, season when they can be found, and their caterpillar host plants are listed. Tips on finding butterflies and caterpillars are given and the life cycle of the Gulf Fritillary is illustrated. Published by Quick Reference Publishing
2. Daniels, Jaret C. 2004. Butterflies
of Georgia Field Guide.
Includes more species than the Minno fold-up guide and has larger color photos, but they are not side-by-side. Also has more information; e.g., tips on how to distinguish each species from similar forms, range maps for Georgia. Species are arranged by color, aiding identification for the beginner. An excellent little pocket size book.
3. Brock, Jim P. and Kenn Kaufman.
2003. Butterflies of North America.
An excellent field book with all the butterflies of North America. Because of this it will be confusing for beginners to sort out the Georgia species from other similar kinds that don't live here. Has range maps, habitat information and tips on discriminating from similar species. Because its coverage is broader it lacks the detail of the Daniels book, but if you want to identify butterflies outside the southeast this is a great book.
The above
are just the books I like and have found useful. There are many others
available. No single book is perfect and each has its strengths and weaknesses.
Tips
on equipment.
Binoculars. It is very helpful to have a pair
of close-focusing binoculars to observe butterflies while they are nectaring
(at rest, feeding on flowers). They should be able to focus on targets 4 to 6
feet away. Many cheaper binoculars do not have the necessary close focusing
ability needed to study butterflies. Some manufacturers have produced
relatively inexpensive models able to focus to a distance of 1.5 feet. Ed Wilde
suggested that you can take digital photos of a butterfly and then use the zoom
feature to enlarge the image so you can see small details. Thanks, Ed!
Do you need a butterfly net? Not unless you want to start a
collection or want to do mark-recapture studies. You can learn a lot more about
butterflies if you examine them close up and that requires learning how to
catch and handle them.
The Ramble. We walked past the international
garden, stopping at the bowl with the floating fern, Azolla. This fern forms a symbiotic association with cyanobacteria
(formerly known as blue-green algae) that are able to fix nitrogen from the
air. (Gaseous nitrogen in the air cannot be utilized by plants until it is
chemically converted to a form like ammonia or nitrate that can be assimilated.
Why is this important? Nitrogen is necessary to make protein. Without Azolla in rice paddys the protein
content of rice would be far poorer.)
We then
passed a crime scene. A large Carpenter Bee was stealing nectar from the
flowers of a shrub. Instead of going into the front door, where pollinators
need to enter the flower to pick up pollen, it was staying outside the flower
and biting a hole in its base and sipping the nectar without getting any
pollen.
There was a
planting of Lantana in the shade and no butterflies present.
Someone asked why.
Butterflies are cold-blooded creatures, unable to maintain a high body
temperature through their own metabolism. In addition, they have a large
surface area in relations to their mass. This means they lose heat rapidly in
the shade and gain it quickly in the sun. In a shaded area they can still fly
if their body temperature is above a critical value, but they may not be able
to do so efficiently or as swiftly because they have cooled. It is better to
avoid the shade and keep their body temperature near the optimum value to be
able to flee any predators that might threaten them.
We stopped
at a Bee condominium to see how it was constructed. Many of the different
species of native bees are solitary -- a single female builds a nest for her
offspring only and leaves them alone once it is provisioned. These bees are
important pollinators for native wildflowers and need to be encouraged by
providing ready-made housing for their nests. The Condo we examined had a
number of pieces of scrap wood into which many holes were drilled. The bees
will use the holes to build their individual nests, supplying them with a paste
of pollen and nectar. Avis sent me a link to a website
that shows how to build a fancier insect hotel.
Butterflies netted and shown:
·
Clouded
Skipper
·
Pipevine
Swallowtail
·
Tiger
Swallowtail (female, dark form)
·
Tiger
Swallowtail (male, yellow)
·
Black
Swallowtail (female)
·
Gulf
Fritillary
Butterflies seen, but not netted:
·
Silver-spotted
Skipper
·
Fiery
Skipper
·
Hairstreak
sp.
·
Giant
Swallowtail
The
Pipevine Swallowtail is interesting for two reasons: 1) The color of the
upperside of the hind wings is structural, not pigmented. From one angle it
looks metallic blue and from another, metallic green; 2) It is distasteful and
serves as a model for a mimicry complex that involves four other butterfly
species.
The
Pipevine mimics are the female Black Swallowtail, the dark form female Tiger
Swallowtail, the Spicebush Swallowtail (not seen today), and the Red-spotted
Purple butterfly (also not seen today). All these species are dark and have
either blue or green coloration on the upper surface of their hind wings. The
resemblance to the Pipevine Swallowtail is not exact, but it is similar enough
to be effective.
The Gulf
Fritillary is thought by some to mimic the Monarch, at least on its upper wing
surface.
Sue asked
why only the female Tiger Swallowtails are melanistic (dark in color, due to
the same pigment, melanin, that produces dark hair in humans). The dark
coloration is caused by a sex-linked gene, but there is a catch. In butterflies
(and birds, too) the female is the heterogametic sex -- meaning that they have
two different sex chromosomes, dubbed Z and W. Male butterflies have two Z sex
chromosomes. The gene for dark wing coloration is carried on the W chromosome
so it can never appear in the males.
The dark
females are the commonest female color; sometimes a black and yellow female is
found in Georgia, but they are uncommon. Outside the geographical area where
Pipevine Swallowtails are found the dark form becomes uncommon and the black
& yellow tiger pattern is typical of both sexes. In other words, the
advantage of the mimetic form is lost when the model is absent.
It was
getting hot in the sun and many were seeking shade to cool off, so we decided
to give the butterflies a break and adjourned to Donderos' as is our custom.
