Arachnophobes, Stop reading Now!

Rambo in the shower- click to enlarge

This is the story of Rambo, our resident Wolf Spider.  A healthy four inch leg span means that he generally shows up before we step on him.  He spent several days in the shower recently, close enough to the outlet handle that we had to reach down slowly to avoid scaring him.
As Joel Vance says in the Missouri Conservationist article Spider! Spider!,

"I also like wolf spiders, gray and ominous. They are predators, stalking and killing other insects, and I like to believe that some of the insects they kill are ones I don't want around, maybe even brown recluses."

When I started the article, we kept Rambo around to hold down brown recluse.  It turns out that there is no evidence to support this.
 

Brown Recluse- click to enlarge

Some sources mention that a small wolf spider can resemble a brown recluse.  A brown recluse is generally less that 3/4 of an inch.  One site suggests that you can tell the difference by the fact that the brown recluse has only 6 eyes.  While true, if you can count the eyes on a spider that small, you are way too close!   Even finding the "fiddle" on the top of the cephalothorax is a challenge if the spider is alive and not in a container.

Missouri Wolf Spider**

If you ever look into Rambo's eyes with a magnifier you can see that he is a soulful spider.  There are 8 eyes, as in the picture, and the upper two large ones showing how sensitive he is.  The two brown hairy structures below are the chelicerae, used for grasping its victims.  These are hollow in spiders and eject venom through the black fangs visible on the inner tips.   
I use the term "he" advisably, as Rambo could be Rambette.  I have never been able to see the palps clearly.  Larger club palps are a male feature, necessary to transfer sperm into the specialized female opening.

Speaking of Rambette, there is interesting research which shows that a female wolf spider (Schizocosa uetzi) can recall information three weeks later.  The males have distinctive patterns on different individuals legs which they wave around to entice females.  Researchers painted different colors on the legs of males and exposed immature females to different color-legged males.  Three weeks later when the females reached ssexual maturity, they selected males of the specific color they had seen three weeks before.  and they tended to eat males of the with the other color legs rather than mate with them. * And you thought your teenage years were dangerous.
Unfortunately there isn't any direct evidence that wolf spiders eat brown recluse but since Rambo spends a lot of time in our bathroom and closets, I am sure that he runs into them frequently.  On the other hand, recent research from the University of Kansas shows that brown recluse spiders prefer dead stuff over killing their own dinner.  Zoogoer*

"New research by Jamel Sandidge, a biologist at the University of Kansas at Lawrence, shows that brown recluse spiders scavenge rather than hunt if given a choice. It's the first time a spider has been shown to prefer scavenging over predation.

There can be as many as 2,000 brown recluse spiders in one house.

Sandidge didn't set out to study the hunting and eating habits of brown recluses—his study was focused on the relative population densities in houses of brown recluses, other spiders, and insects. As the study progressed, however, Sandidge made several unexpected observations about brown recluse behavior. In houses, he saw them eating insects that had obviously been dead for a long time. He also saw them running away from insects. He has even watched a brown recluse remain motionless while a potential prey insect walked over it. In the lab, Sandidge says, "I was feeding them yellow mealworm larvae and the problem was that the mealworms were eating the spiders." Sandidge began killing the worms before putting them in the enclosures with the spiders, and the spiders readily ate them.
Sandidge's curiosity was piqued. He set up new experiments, offering the spiders dead prey and live prey. More than 80 percent of the time, the spiders chose the dead prey. 'Brown recluses are very fragile and very weak,' Sandidge says. They often lose legs or even their lives in encounters with live insects, which may explain why they prefer to avoid them."  from the Smithsonian Zoogoer

If you search"brown recluse" in Google you will get lots of fear mongering sites created by exterminators.  If you see an ad, move on.  Brown recluse bites occur rarely and many "spider bites" are something else.  There is good information at the Wikipedia page or here.
Even if they don't actively eat brown recluse, wolf spiders hunt lots of other insects we don't want in our house.  Rambo (or Rambette for Ann) has a secure future in our creek house.

* These stories and a lot more interesting spider facts are at this highly recommended Smithsonian Zoogoer site.  For instance, did you know that:

• One species of Black and Yellow Garden Spider (Argiope aurantia) dies spontaneously as soon as he inserts his second palp in a female to deliver his sperm, even if he does it mistakenly.  
• A type of jumping spider called Portia is able to learn about its spider prey's preferences.  It plays "music" by setting up vibrations in its spider prey's web.  Trying different "tunes" until it gets a response, it then learns that tune and stays with it until the prey comes toward it.  Portia is also able to strategize, even taking an hour or two to sneak around a tree or object to approach its prey from the back side.  That is a lot of memory time for a spider, (or even an older Master Naturalist.)

** Picture by Dan Johnson
Editors Note:  Sadly, we must report the demise of Rambo, or a wolf spider that looks like him, found dead Monday night in the downstairs bathroom.  There were no signs of trauma (i.e. boot marks or compression injury) and we assume that he died in the line of duty, keeping the shower safe from crickets, beetles and possibly brown recluse.  Thanks for the memories.

Caterpillars with Attitude

Mourning Cloak- Linda Ellis

What could be more benign and peaceful than a caterpillar on a leaf.  After all, they are just eating machines which come out of an egg and fatten up constantly, out growing their skin in three or four molts.  After that, they get down to serious business, the remarkable conversion into a flying and sexually active butterfly or moth. 

Don't Touch My Babies
There is much more to the picture than that.  Many wasps lay their eggs on caterpillars.  Their larvae live in the cat, eventually emerging to form a pupa from which will emerge the adult wasp.  We previously showed a caterpillar parasitized by a wasp.  The video showed dramatically the emergence of larvae from the caterpillar's body with the caterpillar surviving the experience, at least temporarily.
It turns out in some cases that caterpillars even protect their tormentors.  A healthy passive caterpillar can turn into a raging maniac when it has been infested by larvae.  Unknown biological mechanisms may cause it to protect its new "offspring".  This well known phenomenon is shown in a video as a caterpillar actually defends the newborn wasps from a beetle.  It must think the little guys are its own. 

Back Off, Buddy
It also turns out that territorial caterpillars can send a message to the competition.  Some caterpillars can make sounds from hair-like structures on their legs.  This BBC story explains the mechanisms, a strategy not unlike a bull pawing the ground.  The video shows a cat starting a head-butting contest, then sending the scratching message, "Hey you!  Get off of my leaf!" and the competitor scrams.  Could this be the start of the evolution of road rage?

Big Beaks are Cool

Bird beaks can tell us a lot about the eating strategies of a bird.  Beaks have evolved to accommodate the foods of preference as seen at Wikipedia.  The beak is technically the keratinized tissue on the outer part of the mouth (think hard lips), while the whole mouth structure is referred to as the bill.  A good discussion of bill development is at birdchannel.com.
It turns out that beaks may also play a role in controlling some bird's temperature.  Toucans, the Jimmy Durante* of the bird world, were shown in a 2009 study to use their huge beaks for temperature regulation.  The scientists used infrared thermal imaging to measure the surface temperature of the bill of toucans which were in a wide range of ambient temperatures.

“By altering blood flow to the bill's surface, toucans can conserve body heat when it is cold or cope with heat stress by increasing blood flow.  Essentially, the large surface area of the bill, and the fact it is not insulated, means that the blood flowing through is able to release heat into the bill, thus cooling the bird.  This blood-derived heat in the bill is then dissipated into the air,” the scientist adds.  Previous studies have determined that the beak is laced with an intricate network of blood vessels that have the ability to control the amount of blood reaching it.

“Bird bills are not 'dead tissues,' incapable of playing a role in heat balance, but are active contributors to thermoregulation.  Birds do not sweat, so must cope with other mechanisms to deal with elevated temperatures.

Now new studies by the same scientists suggest that bird beak size has evolved to adapt to the temperature of their habitat.  According to Science Daily, Dr Glenn Tattersall and associates examined 214 species across a broad range of beak types and climates.

"By examining bill sizes of a diverse range of bird species around the world, researchers have found that birds with larger bills tend to be found in hot environments, whilst birds in colder environments have evolved smaller bills.

Across all species, there were strong links between bill length and both latitude, altitude and environmental temperature," Dr Matt Symonds says. "Species that have to deal with colder temperatures have smaller bills."

Arctic Tern- Wikipedia

One theory is that larger bills evolve for shedding more heat in warm latitudes.  These investigators feel it is more likely that big heat shedding beaks are a liability in cold climes.  In other words, you are not likely to find hot "lips" in the arctic. 

* Too young for Jimmy Durante? click here to see him.

When Flowers Bloom

Crab Spider Salad- Click to enlarge

Ever wonder how flowers decide it is time to flower?  Me neither, but now that I mention it, that is an interesting question.  Blossom time is critical in both pollination and the timing of seeds which are distributed by wind, insects or other animals.  Further on the food chain, butterfly emergence is important in flower's pollination and predators may be awaiting that time as well, as seen with the crab spider picture from MDC.
It turns out that the flowering season of plants is a response to the length of the day, a process known as photoperiodism.  Try dropping that one in your next conversation.  And how do they remember when it is best for them to flower?  Part of the answer lies in their genes.
A study of a flowering mutant of Arabidopsis, which had an altered response to photoperiod, was used in a study led by Dr Stephen Jackson, as reported in Science Daily.  He and coworkers discovered a mutant gene which altered the blooming time.  "They then cloned a working version of the gene, known as DAY NEUTRAL FLOWERING (DNF), from a normal Arabidopsis plant and introduced it into the mutant plant to restore its normal flowering response to day length."

Scientists can override complex pathways that control flowering by artificially inducing or inhibiting key flowering genes such as DNF and CONSTANS. This can already be done in the laboratory by spraying an 'inducing agent' onto plants, stimulating them to flower early.
This could be used to extend the length of the harvesting season or to co-ordinate flowering or fruit production to a specific time. Growers already regulate the flowering of a few plants such as Chrysanthemum and Poinsettia, the latter specifically for Christmas and Easter.

Imagine the confusion if Spring Cress started blooming in the fall or Deciduous Holly berries appeared in the spring.  I am always concerned when we mess with Mother Nature, but I might forgive scientists if they could get Sericea Lespedeza to forget about blooming.

Caterpillar Motion and Memory

Tobacco Hornworm

The tobacco hawkmoth caterpillar, also known as a tobacco hornworm (Manduca sexta) is commonly studied by scientists.  It is large, easily dissected, has a short life cycle and its nervous system is easily accessible for study.  It also can be fed simply on wheat germ.  Good news for science although not always so hot for the caterpillar.

Caterpillars on the Move
 The current Science Daily has some remarkable findings about the hornworm's locomotion.  They discovered that the caterpillar uses its gut independently to move.

"The Tufts-led team reported that the gut of the crawling tobacco hawkmoth caterpillar (Manduca sexta) moves forward independently of and in advance of the surrounding body wall and legs, rather than moving along with them.

Anyone who has ever observed caterpillars knows that they crawl from back to front in waves. But advanced imaging reveals a surprising picture of what goes on inside.

The researchers used synchronized x-ray and visible light microscopy and videos to study the relative timing of movements of the crawling caterpillar's gut body wall and prolegs (unjointed leg-like structures on the mid-body that grip.)

They found that the gut -- essentially a tube suspended at the rear and head of the caterpillar and decoupled from the body wall -- moved nearly a full step in advance of the surrounding structures. In contrast, gut movement was "in step" with motion of the head and rear.
Furthermore, points within the gut moved at different rates, suggesting that the gut was effectively shortening and lengthening during each crawl cycle."

You could say that this gives a whole new meaning to the term "bowel movement".


Moths Remember Early Caterpillar Lessons
Back in 2008,  Science Daily reported a study on the same species. Scientists showed that a caterpillar can learn lessons that its moth will remember after completing metamorphosis.

"The Georgetown researchers found that tobacco hornworm caterpillars could be trained to avoid particular odors delivered in association with a mild shock. When adult moths emerged from the pupae of trained caterpillars, they also avoided the odors, showing that they retained their larval memory. The Georgetown University study is the first to demonstrate conclusively that associative memory can survive metamorphosis in Lepidoptera.

The brain and nervous system of caterpillars is dramatically reorganized during the pupal stage and it has not been clear whether memory could survive such drastic changes.

The findings of the Georgetown researchers suggest the retention of memory is dependent on the maturity of the developing caterpillar's brains. Caterpillars younger than three weeks of age learned to avoid an odor, but could not recall the information as adults, whereas older caterpillars, conditioned in the final larval stage before pupation, learned to avoid the odor and recalled the information as adults.

The results have both ecological and evolutionary implications, as retention of memory through metamorphosis could allow a female butterfly or other insect to lay her eggs on the type of host plant that she herself had fed on as a larva, a behavior that could shape habitat selection and eventually lead to development of a new species."

Tomato Hornworm

Manduca sexta is closely related but separate from the familiar tomato hornworm as described in the  Missouri Extension website.  The tobacco hornworm has a red hook on its tail while the tomato hornworm's hook is black.  Both species feed on tobacco (good!) and tomato (not so good.)

Wasp Larva on Caterpillar

There is some natural biological help available for the tomato hornworm. A brachonid wasp  lays its eggs on the caterpillar.  The larvae hatch and live inside the caterpillar, killing their host naturally.  If you find these infected worms or cocoons in your garden, leave them there.  These infected caterpillars will create the adult wasps to attack the next generation of caterpillars.   This means sacrificing some of your tomatoes.  One strategy is to plant a few tomatoes away from your crop plants and moving the caterpillars to those sacrificial plants.

Sphinx Moth- tomato hornworm

A common question we get at the Bill Roston Butterfly House is "What does the sphinx moth of the tomato hornworm look like?"  Well here it is.  More on the tomato hornworm is on Wikipedia.

Damsels in Distress

Damselfly- Click to enlarge

Last weekend this beautiful pale damselfly insistently returned to one spot on a branch, giving me a chance to run after my camera and take a portrait.  From here, I will take you on the brief tour of how you could tentatively identify this beauty.
Click on the picture to enlarge it and you will notice the long thin transparent wings, held parallel to the body above the back, a characteristic of damselflies.

Dragonfly

Dragonflies hold their wings straight out, familiar to Master Naturalists as our emblem.  I will cover them in a future post.
Looking up damselflies on Bugguide brings up this page.  The bright blue damselfly in the middle was suggestive in shape with the wrong pattern.  It is a bluette, with wider bands of color, so I backed up to the broader category of narrow-winged damselflies or the pond damselflies.  The next to the last picture was a blue-ringed dancer, but the top of the thorax was too dark to match our friend.
Convinced I was close, I searched the site for "argia" and came up with over a hundred pictures.  The picture that jumped out was the male dusky dancer, Argia translata.  Notice the discussion below the picture with the input of experts and a link to the beautiful dusky dancer pictures by Greg Lasley.

Ebony Jewelwing

The most commonly encountered damselfly at Bull Mills is the
ebony jewelwing, Calopteryx maculata.  Pictured here by Dr. Joe Motto, it is found along the edges of the creek, fluttering deceptively in the shadows like a dark butterfly.  They are strictly predators, feeding on a wide variety of insects including -happily-  mosquitoes and gnats.
Females lay their eggs on water plants and the eggs hatch into larva (naiads) which then live on small aquatic insects. They go through incomplete metamorphosis, resembling small wingless adults.  When the naiads are fully grown, they emerge from the water, molt, and fly off to reproduce.

Information on damselflies in general is at cirrusimage.com,
Incredible variety of dragonflies and damselflies pictures are at Greg Lasley's web site.
Ebony jewelwing picture courtesy of Dr. Joe Motto.

Amphibians and Reptiles

Tomorrow night is the training session on Amphibians and Reptiles and I decided to "get a jump on it" by sending out this National Geographic video showing how frogs jump so far.   Researchers have recently shown that frogs have the ability to stretch their muscles before actually jumping, essentially making them temporarily longer and more powerful.  This enables some bullfrogs to jump 7 feet, over 10 times their length.
In another National Geographic video there is evidence that male frogs intimidate the competing males by shaking their bootie at them.  While entertaining to us, it apparently is either frightening or disgusting to their opponent, encouraging them to use those stretched muscles to get away.
While it is too hot and sultry now to sit out in the early evening and hear the chorus, you can hear their chorus in air conditioning at this MDC site.