Friday, October 2, 2015

Great Golden Digger Wasp

I found several of these large wasps on flowers in a warm season grass field.  I couldn't get them to hold still for pictures and ended up netting this specimen.  It is a Great Golden Digger Wasp, Sphex ichneumoneus, and both the wasp and its lifestyle are colorful.

Gathering nectar on a flower -  Jon Sund
It is found flying from August to October in Missouri, commonly in fields and meadows where it feeds on nectar from flowers.  This is also a good place for finding Orthoptera (grasshoppers, crickets and katydids) which it will sting to paralyze and then fly off with to feed its larva. They do not harm butterflies or their caterpillars.

The female digs a vertical burrow in the ground and create cells branching off at right angles.  She then drags her paralyzed prey into a side cell and lays a single egg on it.  The hatched larva will then feed on its cell mate.

This pattern of stinging a victim and laying the egg on it is not uncommon among hymenoptera including mud daubers collecting spiders in their tubes and cicada killers burying their victims.  What is unusual is its deeply ingrained ritual.

When the  female delivers her prey to the prepared burrow, she first goes down and inspects the chamber, then climbs out, grasps the antennae and pulls it down head first.  If the prey is moved an inch or two away, it will drag it to the burrow, then crawl back down to inspect the burrow again before returning to haul it down.  No matter how many times you move the prey, it repeats the inspection.  This seems to be a genetically programmed behavior.  The behavior of a highly trained entomologist sitting by a hole while repeatedly moving the prey is presumably a learned trait.

Another habit of the wasp described in Wikipedia is the antennae grip.  If the antennae of the prey are removed, the wasp will not drag it down by a leg or other appendage but simply leave it on the ground.  This may be a more practical adaptation as any other grip would mean trying to drag it sideways into a small hole.

I am always amazed that a small and delicate insect like this can dig a chambered tunnel though our Ozark clay and gravel soil that is a challenge for my shovel.  Although not aggressive, the digger wasp will sting if picked up.  It is a beneficial insect and I regret the loss of life in the name of science, but would have regretted it even more if it had stung me.

Thursday, October 1, 2015

Love Your Possum

Opossum beauty - Wikimedia
“The last word in ignorance is the man who says of an animal or plant, ‘What good is it?’ If the land mechanism as a whole is good, then every part is good, whether we understand it or not.”
Dave Shanholtzer sent this Aldo Leopold quote from Field and Stream.  A study by researchers at the Cary Institute helps answer the "What good is it?" question above.  It suggests that a large population of lowly opossums may reduce the risk of tick borne disease.

First, let us consider the underrated possum.  It is so primitive that it arose at the time of the dinosaur extinction.  Most sources point out that it has a very small brain, primitive habits and a relies on escaping danger by playing dead, frequently ending up as the prey of a predator such as a coyote, or a smorgasbord for vultures served up by an SUV.  Its skinny hairless tail, pink nose, gaping teeth and marsupial pouch makes it look like a mammal created by a committee that could never reach an agreement on design.  Vicente Yáñez Pinzón was Columbus' navigator on the  Niña when he first described one.
"Between these Trees he saw a strange Monster, the foremost part resembling a Fox, the hinder a Monkey, the feet were like a Mans, with Ears like an Owl; under whose Belly hung a great Bag, in which it carry'd the Young, which they drop not, nor forsake till they can feed themselves"*
Virginian Opossum - John James Audubon
For several centuries Europeans were fascinated by the strange creature which then illustrated the first maps, in the company of flying fish and unicorns.  It was first named "opossum" by Captain John Smith.  With more than 500 years of curiosity, you might think we would know everything about the possum by now.

New research suggests that we should appreciate the possum for its appetite for ticks.  Dragging along the ground, they get more than their share of ticks, the ultimate opportunists of the arachnid world.  Opossums are clean, grooming more than a domestic cat.  Living in the wild, they constantly accumulate ticks which they then eat, essentially collecting their dinner on their hide.  The research suggests that a possum can consume 5,000 ticks a year!

We are fortunate in Missouri that we don't have the large population of  blacklegged deer ticks that transmit Lyme disease found commonly in the northeastern US.  On the other hand we certainly have our share of Rocky Mountain spotted fever, erlichiosis and tularemia transmitted by our common lone star ticks and dog ticks.

The next time you see a possum chewing road kill on the highway, brake or swerve and give it a friendly wave.   A tick it eats may have been headed toward you.

*The Ashgate Research Companion to Monsters 

Tuesday, September 29, 2015

Orchard Orbweaver

Tonya Smith found this little 6mm spider in the woodland portion of our Master Naturalist chapter's training field trip to Henning Conservation Area last Saturday.  It was on a small web stretched between several branches of a sapling three feet above the ground.  With the naked eye we could catch an almost metallic glint to the abdomen.

Under magnification the abdomen looks like a capsule, decorated with glitter and a peace symbol and then glued to the back of a spider.  In fact, it is original equipment, the standard abdomen design of the Orchard Orbweaver, Leucauge venustaLeucauge is Greek for "with a bright gleam" while venusta is Latin for beautiful, an understatement in this case.  This name was created by Charles Darwin, the only spider he named.

The female typically builds her web horizontally, close to the ground in shrubs and juvenile trees.  She hangs upside down while waiting to trap small insects, allowing her to drop down quickly if disturbed.  She produces eggs throughout the warm season, attaching the egg cases close by on leaves or twigs, home to her young until they emerge and build their own webs.  The adults die with the onset of winter while the eggs survive producing next year's spiders.

Note the eye placemen t- click to enlarge  - Arch Baker *
The color and shape were distinctive in this species but identification of some spiders requires details such as the eye placement.  In this case there are two pair of prominent eyes in the center and two pair laterally arranged vertically as seen above.

MDC Field Guide* License/Copyright: Used with Permission

Sunday, September 27, 2015

A Botanical Year in the Ozarks

During the month of October 2015, Linda Ellis from our Master Naturalist chapter will be showing A Botanical Year in the Ozarks  at the Springfield Conservation Nature Center.  It will display 25 of her botanical watercolors with vignettes of the Ozarks native plants.  The species she has chosen span the Missouri growing season.

Linda has been a botanical illustrator since the early 1980s and has drawn for Missouri Department of Conservation, Missouri Botanical Garden, the U. S. Forest Service, Arkansas Natural Heritage Commission and University of Arkansas. She specializes in illustrations of new plant species which can be seen on her web site at

One of the watercolors is the royal catchfly (Silene regia) above.  It is a very showy prairie plant in the carnation family which gets its name from the heavy coat of sticky, glandular hairs which can trap insects.