Spiders and Snakes

Brown tree snake- Wikimedia

"I don't like spiders and snakes
And that ain't what it takes to love me
You fool, you fool"         -Jim Stafford


Can a venomous snake become the spider's best friend?  A story from discovery.com shows how complex the changes in the food chain can be following the arrival of a foreign snake species.

The culprit is the brown tree snake (Boiga irregularis), a native of Australia and Papua New Guinea which arrived on Guam after 1946, presumably as inadvertent ship cargo.  It has depleted or destroyed many species of native birds and mammals which are naive to the danger and have no natural defenses.

In addition to birds and mammals, according to Wikipedia it has caused "thousands of power outages affecting private, commercial, and military activities; widespread loss of domestic birds and pets; and considerable emotional trauma to residents and visitors alike when snakes invaded human habitats with the potential for envenomation of small children."*

A new study in discovery.com describes a tremendous increase in the number of spiders on Guam, with up to 40 times as many as other surrounding Pacific islands.  Much of this has been attributed to decreases in the bird population due to predation by the brown tree snake.  Birds are major predators of spiders and insects, and small experiments had previously shown that a decline in birds could cause an increase in spider populations.  The surprise here was the dramatic explosion of the spider population.

Islands are particularly vulnerable to predatory invasives.  The resident species have evolved for thousands of years before humans' vessels delivered their dangerous cargoes.  Goats brought for food and the accidental delivery of rats and other invasive species to the Galapagos Islands are familiar examples of this problem.


The brown tree snake is nocturnal, adroit at climbing trees, and normally preys on birds, bats and small mammals.  On Guam they found a smorgasbord of naive birds ready for their picking.  They also left their normal predators behind in Australia. They normally grow up to 6 feet in length but in their new paradise some have grown up to 9.8 feet long.

Their venom is relatively weak and their fangs are located further back in their jaws.  The snakes tend to be aggressive and the venom is injected slowly by capillary action with a chewing motion when their jaws are spread widely.  For this reason they pose little risk humans except for small children.

Major eradication efforts are under way and there is some evidence that the brown tree snake population is stabilizing or decreasing in the face of stress factors and declining food resources.  This latest study simply shows how much effect a recognized invasive species can have on less obvious parts of the food chain.

* Wikipedia

Pale Birds at the Feeder

Our friend Jane Ann Johnson reported that she has been seeing two white birds with yellow beaks at her bird feeder the last week.  Initially she couldn't get pictures of it through the screen.  I suggested that a Master Naturalist would simply cut a hole in the screen.  Since they aren't members, her husband John simply adjusted the focus and managed to get a few good pictures.

Charley Burwick and associates have reviewed the photos.  The first guess was that they are amelanistic House Sparrows.  Their "host" Jane Ann replied that they appeared much smaller than sparrows they also see at the feeder.  The votes are still pending, but the species isn't that important to the story of color.

Bird scientists might debate the exact biologic causes of marked color variation in an individual bird.  Obviously genetics control the normal color of birds which are felt to be important in attracting mates.  It is not for nothing that a peacock drags around the heavy plumage which is metabolically expensive to maintain and increases its risk from predators.

"Cropped" photo- pun intended

There are several genetic variations to explain color change.  First there is amelanism that refers to the lack of melanin in skin and feathers.  This is generally attributed to a genetic abnormality leading to the loss of tyrosinase.  Since the only pigment mammals produce is melanin, loss of this pigment creates albino animals.

On the other hand, other vertebrates such as birds, reptiles and fish produce other skin pigments in addition to melanin.  Amelanism in these animals usually lack the total white and red eyed features.  Look again at the cropped picture and you will notice the yellow beak and legs, slight pigmentation on the trailing wing edge and the dark eye.  The eye is important as pink eyed albino's have vision problems in bright sunlight.

Piebald leucistic Rock Pigeon

Another pigment variation is leucism,  This is a decrease or lack of all pigments due to a defect in the development of all the pigment cells.  Since the animals above have their other pigments manufactured in the same pigment cells, all colors are affected.  This may be their entire body or be partial, as seen in piebald animals with patches of white amid other normal pigmented surfaces.

While having two pale birds show up at the same feeder seems unlikely, Charley reports that others have noted this from time to time.  This takes me back to my days in medical practice when weird symptoms or findings were explained to patients with the vague phrase "We see that sometimes."  Maybe a better explanation comes from the wisdom dating back to 1599, "Birds of a feather, flock together."

What ever you want to call the phenonoma, in the words of our resident birder Charley, it is  "really, really cool." 

Young Eyes II

Dragonfly Larva- Click to enlarge

Young eyes find a lot more critters than mine do.  Leave Lindsay alone with a net and a bucket on the creek and you quickly have a plethora of creatures.  The bucket contains an assortment of minnows whose identity will remain unknown  The star of the show is a dragonfly larva complete with the lateral bugeyes.  On close inspection you can make out the wing buds awaiting development after the next molt.

A late season mayfly cruising along the creek stops to rest and proves to be a willing photographic subject.  Its delicate wings and body seems too fragile to hold, but seasoned entomologists like Kevin and Lindsay hold one until it flies away, none the worse for wear.  This one was as entranced with her as she was with it.


Young eyes find things at every turn.  A dragonfly clinging to a blade of grass has escaped my notice, and she has to keep pointing until I finally see it.  Some species seem to cling longer to upright stems while others prefer horizontal branches.  This one lets me get close for pictures to send off to our odonatologist friends.  Every naturalist should have an odonatologist friend.  If you don't have one, at least memorize the spelling of the word for Scrabble.

Tana Pulles responded to the picture:

"Female Eastern Pondhawk most likely - however young males will look like females and as they mature they change to blue in color starting from the end of the abdomen moving forwards."

Tent Caterpillar egg cases

Even the trees and leaves reveal their secrets to Lindsay.  She points out egg cases on twigs, patiently waiting for me to find them.  They are on a wild plum, one of the Prunus species which will be hosting Eastern Tent Caterpillars next spring.  I had only seen these as the gray dried cases after the caterpillars emerge.


Before they leave, Kevin and his shorter sidekick gift me with some caterpillars to raise.  They were feeding on sycamore and I haven't had time to try and identify them.  Because I was going to be gone for a while I had to release them.  The two green cats were gently placed on young juicy sycamores.  I think the red one was a final instar and since it kept wandering off the leaf into the bottom of the aquarium, I left it to hopefully form a cocoon.  With any luck I will see it emerge and identify the adult.  If I don't, I know that Kevin and his young eyed companion will.

Tarantula

Linda Ellis sent me this picture of one of her hirsute neighbors.  If there was an Oscar for the most misunderstood spider, the tarantula would win hands down.  Its appearance evokes a response somewhere between fear and revulsion, even leading one to star in a movie as a villain.  All of these responses are unjustified.

This is the Texas (or Oklahoma or Missouri) Brown tarantula, Aphonopelma hentzi, a native of Southwest United States.  Although you commonly hear that they arrived in a bunch of bananas, it is a native species whose northern range includes a stretch from Colorado to southern Missouri and as far east as Louisiana.  A. hentzi is considered to be the predominant tarantula species in this range.*  


The brown tarantula is one of the most common species of tarantula thriving in the southern-most United States today. They can have a leg span greater than four inches and weigh more than 3 ounces as adults. The body is dark brown in color, varying both between moults and among individuals.

Although quite memorable when found, they are rarely encountered as their preferred habitat is dry rocky glades.  They spend the day in silk lined burrows, frequently abandoned rodent or snake burrows.  They do not build a capture web but extend silk strands outward to act as trip wires.  At night they emerge to hunt crickets and other insect prey.  Large tarantulas are said to kill small mammals and even birds.

Tarantulas will mature sexually after 7-12 years.  The males have longer legs and will strike out in August and September looking for females.  After mating they will usually die within a few months.  The females stay close to their tunnels so the tarantulas we see out and about are usually males.

Note small eyes- T. J. Morgan

Large wolf spiders are frequently confused with tarantulas.  Wolf spiders have much larger eyes and like other spiders, their fangs move laterally while tarantulas' fangs move vertically.  Unfortunately, viewing a spiders' fangs means you are extremely close and looking under its palps.

Wasp and its prey

Even a large hairy spider has enemies.  In addition to birds and lizards, they, like many insects are victims of parasitic "tarantula hawk"wasps of the Pompilidae family.  These wasps paralyze the tarantula with a sting and lay an egg on it.  It then drags the spider into a burrow or a crevice where the wasp larva consumes it. 

Fangs- amazingtarantulas.com

Now back to fear and loathing.  Although a Texas brown tarantula comes equipped with an impressive set of fangs, its venom has little effect on humans and is never fatal.  They bite only when attacked or roughly handled and a bite is usually no worse than a bee sting.  Since they are unlikely to bite when handled gently, some people keep them as pets as seen in Youtube pet videos.  Handling a house pet tarantula may be a bit much for some of us but it does show that they are generally docile.

They have a second line of defense which affects animals that are sniffing them or touch their undersides:

"New-world tarantulas (those found in North and South America) are equipped with urticating hairs on their abdomen, and will almost always throw these barbed hairs as a first line of defense. These hairs will irritate sensitive areas of the body and especially seem to target curious animals who may sniff these hairs into the mucous membranes of the nose. Some species have more effective urticating hairs than others." Wikipedia

Bottom view with fangs- T. J. Morgan

The fear of the tarantula dates back to the middle ages in Taranto, Italy where it got its name.  Its bite was said to produce severe pain, spasms and exhibitionism, and death.  The only cure was said to be wild dancing, the origin of the folk dance known as the tarantella.  Neither the bite nor the cure have been documented in modern times.

Finally, what about the movie star spider I mentioned above.  A tarantula named Thomas was induced somewhat reluctantly to crawl across Sean Connery's chest in the first James Bond movie, Dr. No.

The most comprehensive information is in this PDF.

Young Eyes

An afternoon spent in the woods with Lindsay and her father Kevin led to a series of discoveries I would not have made on my own. The next few blogs will describe the adventure of seeing the land with "young eyes."

American Toad?- Bufo americanu

The woods look a little different to a set of young eyes.  They aren't distracted by the conversation of their elders recalling the time they saw a bear on the tree when there is something that just wiggled a leaf on the ground.  It also helps that those eyes are set lower to the ground.

Lindsay is quick and fearless when it comes to catching critters.  This little toad escaped several times, only to be recaptured and studied before its final release.  This wasn't its first adventure in life.

She found it on our driveway, the edge of a glade on top of a short bluff twenty feet above the creek.  It started life as one of thousands of eggs laid by its mother in slow moving water along the edge of Bull Creek.  As the drought progressed, the creek dried up, leaving only a few inches of water, pooling in a desert of dried gravel.  Most of its fellow eggs became emergency rations for a wide variety of minnows, shiners, frogs and carnivorous aquatic larvae struggling to survive.

Life as a tiny black tadpole wasn't much easier.  Everything seemed to be chasing the dense school of its classmates which were picked off one at a time.  Just in the nick of time its little legs developed as its tail shriveled up.  It started its land journey as a half inch toadlet, searching for small insects and avoiding birds, snakes and other dangers.

... and the cycle starts again.

Eventually, by a series of random hops it arrived on our drive, only to be caught by a giant blonde biped.  It was fortunate that this particular mammal wasn't hungry, only curious.  Our toad may well grow up to feed on the insects drawn to the cabin lights and eventually head down to the creek to rear next year's toadlets.

Springtail Invasion

Springtails hit the wall

Our friend Georgia saw thousands of tiny insects crawling up the side of her house.  They seemed to be emerging from the wet soil during a rain storm, covering a wide area.  They were a gray color,  less than 1/16 of an inch long and they tended to hop.  Her questions were what are they, could they become a problem by invading the house and should they be sprayed?

She happened to have her old dissecting microscope left from her days as a biological microscopist and was able to get some magnified pictures.  We sent the pictures to Dr. Chris Barnhart who identified them as springtails, a harmless horde.  With this information, she spared thousands of lives.

High magnification- Georgia P.

Springtails (Collembola) are hexapods (six legs) but are no longer considered insects by some researchers based on DNA studies and anatomical variations.  Insects have external mouth parts while springtails' mouth parts are internal.  These authors argue that springtails and their 6-legged insect cousins evolved from separate lines.

Although a few species are found up in trees or on the edges and surface of ponds,  many species are found in damp soil and leaf litter.  They consume dead plant and animal matter, eventually contributing to the creation of soil.  They also consume fungal mycelia and transport mycorrhizal fungi which contribute to
the growth of plants.
 

Furcula set to spring- Wikimedia

They get their name from an escape mechanism that allows them to "jump."  A structure called a furcula is attached to the abdominal tip.  It folds under the body, held under tension like a spring.  When danger approaches it snaps, with the springtail sailing quickly in the air.  They can jump as high as two inches, 30 times their body length,  the equivalent of a 5'10" man jumping 175 feet straight up...from a standing start!  While not quite in the league with fleas, it is
still pretty impressive considering they aren't using their legs.

End-to end, 16 per inch

Springtails commonly emerge in massive numbers in homes or other human structures such as Georgia reported.  Although they don't bite like fleas or carry disease, their migrations can be alarming and lead to calls for help by homeowners.  They usually die off in a week.  Prevention includes eliminating damp places for them to gather.  The ucdavis.edu website has advice on management.

Thanks to the ever observant Georgia Pozycinski for the pictures and the call.

Hummingbird CPR

Emergency Medical Transport

Our friends, John and Jane Ann Johnson are a frequent source of interesting bird observations.  John's extensive training as a cardiologist led to saving a bird's life.  Well, maybe the training didn't have anything to do with it, but the result was still great.  First there was the safe handing of the injured bird- Emergency Medical Transport.  Next came the technical skills needed to safely introduce fluids.  Here is his story:

"Thursday I found another dead hummingbird on the hangar floor. They can never get out, even with both big doors open. This happens once every week or two. I picked her up to toss her in the trash and she flopped once- still alive, barely.

I spent the next 90 minutes with an eye dropper filled with hummingbird nectar trying to revive her. She became more animated, began to flap her wings a bit, and finally flew off. Pretty neat...and surprising."

Catheter skills come in handy

There is a lot of advice available on what to do when you find an injured bird.  Birds have high metabolic rates, requiring lots of food.  Most species have complex diets spanning the range of seeds and insects to fish, small mammals and even scavenging dead animals.

Fortunately, John's bird had relatively simple dietary needs in this crisis.  Hummingbird feeder solution provided both calories and hydration.  Hummers do consume insects, but during the current migration period they mostly need energy in the form of nectar, natural or artificial.

Here are some general hummingbird tips from our own Charley Burwick:

• Do the right 4:1 water and sugar mixture, do not use red coloring
• Keep the feeder fresh, usually in hot weather no longer than 2-3 days, clean with bleach, and rinse thoroughly
• Use a feeder hanging from the garage door, or even on the ground when a hummer is caught in the garage (common occurrence)
• Keep at least one feeder up until the end of the calendar year, you may get a rufous hummer that migrates this direction in the fall, and some ruby-throated are really slow leaving, especially the females, and first year birds.

Anyone who has ever tried to get a bird to fly out of their house or garage can commiserate with the problem of pointing one out of a hangar.  This is even more complex at the Botanical Center's Butterfly House, a mesh enclosed structure where everything looks like an exit.  I can recall watching a bird flutter around the ceiling of Hammon's Hall during a symphony concert.  Possibly it thought that Camille Saint Saen's suite Carnival of the Animals was on the evening's program.

As with deer in our suburban neighborhoods, we are having to learn to live with nature, and visa versa.  Increasing human populations expand into what was previously wilderness.  As our footprint on the planet increases with larger structures, taller glass buildings and more wind turbines, we will likely have more opportunities to deal with injured birds.

Wildbirdcarecentre.org has a lot of good information on the care of injured wild birds.

Food for thought

Click to enlarge

This was found in the middle of the woods, 300 feet above Bull Creek.  It was spread in a dense mat, bright green standing out against the browns of the drought challenged trees.

This provides habitat for several creatures far from their usual home.  It also provides high protein nutrition for birds fortunate enough to find it in this remote location.

What is it?  Comments below.

Beware the Cherry

By Jennifer Ailor, Master Naturalist

Black cherry is a fairly common tree in the Ozarks’ woodlands. The timber is valuable, and birds and other critters love the clusters of tiny bright red cherries in summer and fall.  But black cherry trees aren’t good for cattle and horses, and if you have any in your pastures or fencerows, they should be removed if you want to keep your livestock safe.

The problem is that the leaves of the tree, especially when wilted, can deprive livestock of oxygen if eaten. The leaves contain prunasin, a cyanide that can be fatal.  In conditions like this summer when trees are stressed by the heat and lack of water, wilting breaks down the prunasin and releases the cyanide, according to the University of Missouri Extension.  Symptoms of poisoning include gasping, weakness, excitement, dilated pupils, spasms, convulsions, coma and respiratory failure. Not a pretty sight.

Cherry bark- like potato chips

When removing cherry trees, which have a tendency to sprout, the Extension recommends promptly applying a systemic herbicide to the fresh stump. And, of course, remove all branches and leaves that livestock might munch on. If you don’t want to use a herbicide, be prepared to cut sprouts for several years.

I have a small cherry in my horse pasture. You can bet its days are numbered.

Editor's note: 
Black cherry, Prunus serotina is a native tree whose range extends to the eastern border of Kansas.  It is a pioneer species, being one of the first trees to grow in disturbed soil, frequently replaced later by other species.  Imported to Europe, it has become naturalized and is now considered an invasive species in many forests.

A wide variety of moth larvae and Eastern Tiger Swallowtail caterpillars feed on Prunus species.  In the spring you may locate black cherry and plums from a distance by the dense nests of the Eastern Tent Caterpillars which are dependent on trees in the Prunus and Malus (apple) family.  Early pioneers treasured black cherry fruit for making rum and brandy called cherry bounce.  We are more likely to encounter our bounce in a jelly or Black Forest chocolate cake.

Why Metamorphosis?

A friend sent me a thought provoking article titled How Did Insect Metamorphosis Evolve? from Scientific American.  When you consider that everything an organism does uses some of its precious energy, something like metamorphosis doesn't initially make sense.

Incomplete metamorphosis *

First, consider what is involved in metamorphosis.  Incomplete metamorphosis refers to the process that insects such as grasshoppers, stick insects and a number of other species go through to grow.  It begins as an egg with a nymph emerging, undergoing molts while resembling the parent, although lacking the final stages of adulthood such as sexual organs and in many cases, complete wings.

Complete Metamorphosis begins as an egg which produces the larva.  After multiple molts, the larva pupates and emerges as a completely different organism, both in appearance and function.  Think of the caterpillar pupating and the butterfly emerging.

Complete metamorphosis *

Complete metamorphosis requires a lot of energy.  Any time an animal or plant expends energy, such as a deer growing horns or honey locust producing long thorns we assume that it had some advantage to the organism.  

The article above discusses the theories of how metamorphosis evolved.  At the last, it answers my question of "why bother to change forms?" Why curl up in a dormant state, wrapping the body in silk and then transform into a totally different body, frequently with not only different structures but even changing food sources such as changing from a herbivore to a predator?  There must be some survival value.  As the article states, "Metamorphosis was so successful that, today, as many as 65 percent of all animal species on the planet are metamorphosing insects."

So what is the advantage to metamorphosis?  Here is the answer in their words:

"The primary advantage of complete metamorphosis is eliminating competition between the young and old. Larval insects and adult insects occupy very different ecological niches. Whereas caterpillars are busy gorging themselves on leaves, completely disinterested in reproduction, butterflies are flitting from flower to flower in search of nectar and mates. Because larvae and adults do not compete with one another for space or resources, more of each can coexist relative to species in which the young and old live in the same places and eat the same things. Ultimately, the impetus for many of life's astounding transformations also explains insect metamorphosis: survival."

 Unfortunately this doesn't answer my last question- why does the honey locust still have thorns?

Thanks to Kevin Firth
*  Drawings from MuseumVictoria.com 

Purple Passion Flower

If you want to get Barb excited, let her find a new or unexpected wildflower.  She yelled "stop" as we were driving along the field edge in an area cleared by the cleanup of a fallen tree last winter.  It was a big cluster of purple passion flowers.  The flower is so distinctive that even I can identify it now.

The passion flower plant is said to have medicinal properties discussed below, but the "passion" isn't what you might be thinking.  When the Spanish discovered this flower in Peru in 1569, the Friars saw symbols of Christ's Passion in the blossom, the source of its common name.  They took this as a positive sign that they had his blessing on their mission.  The interpretations of these complex symbols are described here,

Purple passion flower, Passiflora incarnata, is a flowering vine which spreads along the ground until it finds a convenient shrub or tree to climb.  As the vines sprawl along the ground they develop root suckers, (rhizomes), increasing their local spread.  This means that all the plants within this space are most likely genetically identical.  In gardens, they can tend to take over but they have a lot more competition in our valley.

The leaves are distinctive, all with three fingers similar to some sassafras leaves but with deeper indentations.  They are far more numerous than the scattered flowers.  The leaves serve as the larval food source for the Variegated Fritillary and its southern cousin, the Gulf Fritillary which arrives in late summer.

Passiflora produces a very distinctive fruit, called a Maypop, although why "May" escapes me as it fruits in late summer.  It is also called a wild apricot or apricot vine.  It produces a large green berry that turns orange, providing a good food source for wildlife.  It can be eaten raw and was eaten by Native Americans.  Passion flower seeds have been found in some thousands of years old archeological sites.  No less than John Muir called it "the most delicious fruit I have ever eaten."  Ours are just starting to form, probably quite a struggle in the midst of the drought.

Fruits are forming

The plant, fresh or dried has been used to treat anxiety and narcotic withdrawal.  There are a lot of ongoing studies to determine its effectiveness in these and a variety of other disorders.  These are summarized on the National Institutes of Health web site.


More pictures are at missouriplants.com.