Thursday, September 19, 2013

September 19 2013 Ramble Report




Today it seemed appropriate to remember the Irish poet Seamus Heaney who died a couple of weeks ago, so Dale Hoyt read one of his poems. (Note: The flax-dam in the poem is a pond in which the stems of Flax stems are placed in the water to rot, releasing the fibers that were used to make linen. Many Irish towns had such flax dams.)

Death of a Naturalist

All year the flax-dam festered in the heart
Of the townland; green and heavy headed
Flax had rotted there, weighted down by huge sods.
Daily it sweltered in the punishing sun.
Bubbles gargled delicately, bluebottles
Wove a strong gauze of sound around the smell.
There were dragon-flies, spotted butterflies,
But best of all was the warm thick slobber
Of frogspawn that grew like clotted water
In the shade of the banks. Here, every spring
I would fill jampotfuls of the jellied
Specks to range on window-sills at home,
On shelves at school, and wait and watch until
The fattening dots burst into nimble-
Swimming tadpoles. Miss Walls would tell us how
The daddy frog was called a bullfrog
And how he croaked and how the mammy frog
Laid hundreds of little eggs and this was
Frogspawn. You could tell the weather by frogs too
For they were yellow in the sun and brown
In rain.
Then one hot day when fields were rank
With cowdung in the grass the angry frogs
Invaded the flax-dam; I ducked through hedges
To a coarse croaking that I had not heard
Before. The air was thick with a bass chorus.
Right down the dam gross-bellied frogs were cocked
On sods; their loose necks pulsed like sails. Some hopped:
The slap and plop were obscene threats. Some sat
Poised like mud grenades, their blunt heads farting.
I sickened, turned, and ran. The great slime kings
Were gathered there for vengeance and I knew
That if I dipped my hand the spawn would clutch it.

We planned to focus on butterflies again today, but it was cool when we began, not a good sign for butterfly activity. Butterflies prefer hot, sunny weather, so we left the parking lot with low expectations. But with so many sharp-eyed participants it wasn't long before we found lots  of interesting creatures.



NOTE: All photographs following were taken by Don Hunter.
Click here to see more of Dan's great pictures. 
At an arbor on which Blue Passionflower (Passiflora caerulea) was growing someone spotted a number of orange and purple caterpillars -- the larval stage of the Gulf Fritillary (Agraulis vanillae). Several of these were large enough that they were probably close to metamorphosing into the next stage, the pupa (called a chrysalis in butterflies).  And, sure enough, another sharp-eyed person spotted an empty chrysalis attached to the arbor itself.

Golden Garden Spider on web
Then we noticed a large orb web suspended at the back of the arbor and, at the center of the web, a large yellow and black spider -- a Golden Garden Spider (Argiope aurantia). 

The center of the web has a distinct band of silk called a stabilimentum. The function of this structure is unknown, but one hypothesis is that it warns birds of the presence of the web. The stabilimentum reflects UV light and birds have the ability to see in the UV part of the spectrum. They may avoid tangling up their feathers if they can see there is a web ahead and swerve to avoid it.




Yum, yum!
Someone asked if I would throw a fly into the web, to see what would happen. Lacking a fly, I threw one of the nearby caterpillars into the web. There was no immediate response, probably because the caterpillar did not struggle. When I shook the web a little the spider rushed over and, after a moments hesitation, began to sheath the caterpillar in silk, finally hanging it in place on the web.




A spidery sack lunch.
There were gratuitous remarks to the effect that you can't take the child out of the man, but these were ignored.

And then Donna spotted the trophy of the day:  A spherical, brown thing the size of a golf-ball suspended by a network of silken thread from leaves at the edge of the spider's web. This was the egg case of the Golden Garden Spider!

Two more spider signs were observed, the webs of the Spiny-backed Orbweaver (Gasteracantha cancriformis) and the egg cases of a Basilica Orbweaver [?] (Mecynogea lemniscata). The eggs cases of the latter species are long chains of cases suspended from silken "clothes lines." The web of the Spiny-backed Orbweaver has characteristic silk supports -- stretches of thin  silk alternate with thicker, fuzzy silk. This is characteristic of this species, so if you see such a web you don't have to see the spider to know who made it.




Ed found a Clouded Skipper (Lerema accius) basking in the morning sun on a yucca blade. When skippers bask they orient themselves so that they are maximally exposed to the sun and open their hind wings almost horizontally, while opening their fore wings only about 30 degrees. This posture is thought to increase the area exposed to sunlight and hasten the warming process.

Motion just below the skipper attracted out attention: an American Chameleon (Anolis carolinensis) was out looking for dew. As we watched it licked the surface of the yucca leaf. This is the way in which anoles get water. If you ever keep one as a pet you must spray the plants  and the glass of the cage each day. Placing a dish of water in the cage won't work; the anoles don't know how to drink from a container.

Someone asked about anoles changing color. The American Chameleon is not a true chameleon. It can only change from green to brown and vice-versa. They are usually green when foraging in vegetation and change to brown when cold. But they also become green when frightened, as when they are handled.

On some goldenrod flowers we found two interesting insects, a small group of true bug nymphs, colored black and red (are these UGA bugs?). Consulting bugguide.net, these seem most similar to the Florida Predatory Stink Bug ( Euthyrhynchus floridanus). These, as the common name implies, are predators and this would explain why they were found with a dead Scoliid wasp.

The scoliid wasps are interesting. They are parasitoids of the grubs of scarab beetles that live in the ground. (A June bug is an example of a scarab beetle.) They dig into the ground to find the grub, sting it and then lay an egg on it. The egg hatches and the wasp larva feeds on the paralyzed grub. The adult wasps feed on nectar.

A "long-horned" grasshopper
Nearby we discovered a long-horned grasshopper, so-called because its antennae are longer than its body. It is a member of the family Tettigoniidae in the order Orthoptera. This family is sometimes collectively referred to as "katydids." Others restrict the term "katydid" to tettigoniids that mimic leaves. 








A "short-horned" Grasshopper (missing the jumping legs)
Later we discovered the nymph (an immature stage) of a "short-horned" grasshopper. Its antennae are much shorter than its body. It is a member of the family Acrididae in the order Orthoptera.

Wow! An hour had gone by and we had barely gone 500 feet!









Pausing at an arbor supporting the vines of a hop plant we noticed that some of the leaves were extensively damaged and surrounded by silk webs. This was due to the activity of caterpillars. Some species protect themselves by enclosing their food plant in silk webbing, preventing parasitic wasps from gaining access. Many of the silk webs had been abandoned but others had small caterpillars covered with white fuzz. These are undoubtedly moth larvae, but I don't know what kind. 

Someone did spot a chrysalis hanging among the hops. Again consulting bugguide.net when I got home, I was able to identify it as the pupal stage of the Eastern Comma (Polygonia comma), an Angle-wing butterfly. You can see in the photograph a feature commonly found on butterfly chrysalids -- bright, metallic spots. No one understands what function these have, but they certainly are decorative.

BTW: The hops that develop on the hop plant resemble the fruits of the Hop Hornbeam tree. That's the origin of its common name.





At the flower beds toward the other end of the garden we found some active butterflies. We caught and examined a Fiery Skipper (Hylephila phyleus), Gulf Fritillary, Red-spotted Purple (Limenitis arthemis astyanax) and Sleepy Orange (Eurema nicippe). Some of us also saw a Buckeye (Junonia coenia), Cloudless Sulphur(Phoebis sennae), and female Tiger Swallowtail (the dark form) (Papilio glaucus).

After which we retired as usual for conversation and snacks at Donderos'.

Dale

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1 comment:

  1. Dale, this was probably one of the more interesting rambles of the season, particularly since our expectations were so low as we headed out. The stretch from the Blue Passionflower arbor to the hop arbor was really rich, with nature in abundance. And I now know what retting is, too, thanks to Hugh's reading!

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