NATCHEZ NATURALIST
NEWSLETTER:
from the woods near Natchez, Mississippi, USA

June 16, 2002

BLACKBERRY WEEK
A few ripe blackberries have been appearing here and there for a couple of weeks and they'll be turning up for another month or so, but I'd say that this last week will prove to be the best blackberry picking week of the whole year. In my April 21 Newsletter I said that the blackberry brambles with their "white blossoms surge from the woods' edge into the broomsedge field like a tide of warm, green water with white froth." Now the white froth has crystallized into red and black berries -- red being the color of unripe fruits.

If you pick in the morning when it's cool, the dew wets your feet and legs, and mosquitoes can be pretty bad. If you wait until later, the humid heat pushes down on you the way Mississippi heat does. Nonetheless, I prefer picking in the afternoon, sweat streaming down my legs, and feeling the powerful sunlight slow-baking my bones.

When you're out there you know you're alive because all your senses are being tested. The canes' stickers catch your britches legs. When you get scratched, a straight line of crimson beads of blood form on your wet skin. In the vacuum of the heat-stymied afternoon you hear the light thumps of berries dropping into your bucket, and the rustlings of the Cardinals upset in the briars, for the bramble is their home and they love those berries as much as you. Your hands grow purple- stained and so do your lips. Sometimes a spider or a stinkbug gets into your bucket, but you just pick it out.

Something funny always happens at the end of a good picking session. When the bucket is nearly filled, though you've been watching the harvest grow one berry at a time, suddenly you're surprised by what a mess of them you have, and how handsome and substantial they look all glossy and plump, and so black that they're almost blue. You almost feel as if in that field you've rediscovered a subtle but powerful wisdom: That one berry at a time, if you keep at it, leads to a beautiful heap of berries.

*****

BLACKBERRY BOTANY
Blackberries, raspberries and dewberries are all very closely related. They are all members of the Rose Family, and they all belong to the same genus RUBUS. It's easy to distinguish which is which.

When you pick a raspberry, the berry's pale, more or less conical "core" remains on the bush. The raspberry fruit, then, has a hollow center. When you pick a blackberry or a dewberry, the "core" remains inside the berry.

Dewberries grow on slender stems that trail on the ground and root at their tips. Blackberry stems are generally heavier and while they may arch and sometimes even root at their tips, the canes don't trail on the ground and the tip-rooting isn't extensive.

When I listed all the flowering plants I could find growing naturally in my home county in Kentucky I listed four RUBUS species. In fact I had no idea how many species we had there.

That's because the genetic situation with the genus RUBUS is different from that in most plants. In this genus plants can reproduce the usual way, via pollination and sexual fertilization, but many species also reproduce through a strange phenomenon known as apomixis. In apomixis, flowers produce fruits without pollination or fertilization taking place. The flower's unfertilized ovule develops into a seed.

Thus the plant resulting from such a seed is a clone of the parent plant, even though it was produced from a flower and grew from a seed. Possibly the field of blackberries in which I've been picking this week is a field of clones. Every blackberry plant out there could be an exact genetic duplicate of its neighbor.

Because of this and other strange things going on at the genetic level in RUBUS (polyploidy, frequent hybridization and more), according to the usual definition of "species," there appear to be thousands of RUBUS "microspecies" that occur in only one tiny local area.

When I was in college, genetics seemed to be a relatively simple field. Now we know that genes do very unexpected and often unexplained things. More than one gene-philosopher has suggested that we living things are just the ephemeral vehicles that genes use to get what they want. And what the genes want is to be perpetuated as they evolve through time exploring new, ever-more complex and kinky combinations among themselves.

*****

WOODRAT, SPOON, BEANS, CORN SNAKE & MOSQUITOES
In the December 9 Newsletter I told you about the problem I have with Eastern Woodrats in my toilet. I said that woodrats are very unlike house rats, but are the same thing as the "packrats" and "traderats" we hear about in TV Westerns. Lately my Eastern Woodrats have been behaving like real packrats.

Saturday morning when I began preparing breakfast I discovered that during the night they'd stolen not only one of my two spoons, but also every single green-bean I'd picked the day before, planning to cook during breakfast. That was about a quarter of a bushel of beans, so one or more rats must have been busy the whole night, and now they have a nest someplace formed mostly of green beans and my spoon, and a knife lost a few days earlier. I've also had to clean twigs out of my toilet several times as they continue to try to convert that into a big nest.

As my cornbread baked and I fumed about losing my beans, spoon and knife, I heard some Tufted Titmice and White-eyed Vireos issuing their alarm calls. I figured they'd spotted a snake so I went there to see, and sure enough they were mobbing a five-foot-long (1.5 meters) Corn Snake, ELAPH GUTTATA EMORYI, lying calmly on a Sweetgum's horizontal branches about 15 feet up (4.5 meters). Last year a Corn Snake hung out in my toilet. It was about 3 feet long so I wonder if this is the older edition of that one. This snake was light gray with brown or dark gray blotches. Th species is one of the prettiest, most gentle-natured snakes we have, and it eats rodents, birds and bats. I was tickled to see that my visitor was big enough to swallow a woodrat. You can see a Corn Snake at fwie.fw.vt.edu/VHS/corn%20snake%202.jpg

The visit was disconcerting in one way, however. As I was admiring the Corn Snake through my binoculars, I noticed that several mosquitoes, swollen with red snake-blood, clung to his body from head to tail. Just thinking of being covered with mosquitoes and having no hands or even a horse's tail to swat at them made me cringe. All the poor snake could do was to lie there letting the mosquitoes work their will.

*****

KATYDIDS GALORE
Now that warm weather has arrived I'm again sleeping outside on a wooden platform in the woods. The platform stands about waist high, well above the ticks, and is covered with a mosquito net.

When night falls there comes into the forest a magnificent roar consisting of the calls of thousands of Katydids, PTEROPHYLLA CAMELLIFOLIA. The songs are loud and raucous, similar in quality to the buzz-saw drummings of the periodical cicada, except that they come in short bursts, something like "rik-rik, rik-rik, rik-rik." The wonderful thing is that usually the calls are synchronized so that the roar pulsates with a mighty rhythm. Lying beneath the net I often discover foot keeping beat. The pulsating roar is almost hypnotic, and I can see how certain nervous-type individuals could be driven mad by it. Fortunately, I find it restful and I am glad to experience it.

Well, I am only about 99% sure that these are Katydids. I have tried dozens of times, flashlight in hand, to spot one as it calls, but to no avail. These are tree-top singers and call only at night

One source of my slight doubt about their identify is that what I hear now is not the same katydid call I knew during my childhood in Kentucky. Kentucky's katydids call in the same loud, buzzy manner, but in Kentucky it makes sense when people claim that katydids say their name -- "Katy-did, Katy-didn't. Katy-did, Katy-didn't" There's just no "Katy-didn't" to our "rik-rik."

However, I found a page on the Internet where a researcher says that "Southwestern populations call with a slow pulse rate and only one or two pulses per phrase." Natchez is considered to be in the Southwestern part of the katydid's distribution and "two pulses per phrase" is exactly right for what I hear. This specialist claims that there are at least three distinct Katydid populations, each having its own characteristic call. There are Northern, Southeastern and Southwestern populations.

On the above-mentioned Web page there are also audio files where we can hear the three katydid accents. Unfortunately, I built my computer from miscellaneous parts and I never got around to buying a sound card for it, so I cannot hear audio files. Therefore, how about this: If any Newsletter subscriber in Mississippi is hearing my "rik-rik" sounds in the woods at night, and if you have a sound card in your computer capable of digesting WAV audio files, could you go to the following address and see if what you hear in the woods is what the audio file sounds like?

You can see katydids, view maps showing the distribution of the three regional populations and hear a variety of Katydid calls demonstrating all three "local accents" at http://buzz.ifas.ufl.edu/141a.htm   The address with a recording of a male Katydid calling in Texas (thus also with our "southwestern accent") is http://buzz.ifas.ufl.edu/142sl3.wav

These critters call all night, beginning exactly at dusk, and ending exactly as dawn, though they tend to trail off right before dawn. There's an exquisite period of several minutes when a few katydids are calling while the Cardinals and Summer Tanagers are just awakening, mingling their peaceful mornings songs with the thinning Katydid drones.

*****

SENSITIVE BRIAR
An interesting plant blossoming in our area right now is the Sensitive Briar, sometimes called Bashful Briar, SCHRANKIA MICROPHYLLA. This prickly, trailing plant has leaves and flowers looking like leaves and flowers of the pretty Mimosa, or Albizia, tree -- the leaves being feathery looking and the flower clusters consisting of pinkish, powderpuff-like globes. This plant is common at the edge of fields and along roadsides. Touch its feathery leaves and they quickly droop and fold up. You can see Sensitive Briar at www.virtualherbarium.org/lf/mimosa.jpg. Also there's a beautiful close-up of two flower clusters at www.flwildflowers.com/wildflowers/schrank100.jpg

Why is the Sensitive Briar so sensitive? My guess is that the quick leaf-drooping is mainly a trick the plant uses causing its leaves to look less palatable to mammals grazing the area. As a browser moves through the field it touches plants that touch the Sensitive Briar. By the time the browser reaches the Sensitive Briar, the briar's leaves are droopy, showing their silvery undersides, and looking like something diseased and dried-up. Why should a browsing animal eat a sick leaf when more succulent, healthy-looking ones stand next to it? This is only my guess, however. I've never seen anyone try to explain it. The technical name for such plant movement caused by touching is "thigmonasty," by the way.

*****

THE NORTH AMERICAN BREEDING BIRD SURVEY
If you are interested in how our native bird populations are doing in the face of ongoing habitat destruction and pollution you may be interested in the homepage of the US government's North American Breeding Bird Survey at www.mp2-pwrc.usgs.gov/bbs/

Here you can find the raw data used by wildlife managers, scientists and people like us to analyze the welfare of more than 400 bird species. By clicking on "USGS Results and Analyses" you can gain access to species trend estimates, distribution maps for each species, and much more. This is fairly technical statistical data so you may need to use the help button to understand it, but there's plenty there to digest.