Thursday, January 18, 2018

Winter Birds



"Don't shoot, I'm a bird!"- REK
At lunch today we were talking about which birds win at the battles over our bird feeders.  Aside from the long-tailed not-a-bird that we yell at, there is a pecking order with the red-bellied woodpecker on top and our poor Carolina chickadee usually coming in last.  In between it is harder to tell who wins in beak to beak combat.  Then I saw the latest issue of Cornell Lab eNews with a report from a team of researchers that kept score, describing the ranking of 136 common species' dominance at the feeder.  It turns out that while bigger is better, it doesn't always trump guts and strength.  You can see the scorecard here.

Winter party with a few friends - Bill White, MDC
A companion article describes How Birds Survive the Cold.  Actually the factors sound a lot like a doctor's advice on winter health in a newspaper column. 
  1. Eat all the healthy food you can shove in your beak.  In this case especially eat fatty foods like sunflower seeds and suet, just not so much you gain weight. Energy equals heat, especially when you need to shiver.
  2. Dress warm.  Fluff up your feathers and when possible tuck your feet in.
  3. Hang out with friends.  They will keep an eye out for predators and may know the best local eating places.  And, like the joke about two fishermen and the grizzly bear, you don't have to be faster than the predator, just faster than your friends.
  4. Protect yourself from windchill.  Get on the other side of the tree or on the ground in the grass and shrubs.
  5. Snuggle in at home out of the cold, even if it is a hole built by a woodpecker.  This downy created a side entrance to a vacant bluebird house and filled it with dead grass.

Sunday, January 7, 2018

Incredible Walking Sticks

Giant Walking Stick
A WOLF school student's presentation on stick insects, (Phasmatodea aka walking sticks) sent me down a rabbit hole of researching these incredible insects.  Aside from color and size variation of our local sticks there is an incredible diversity of species across the globe.  Here is just the tip of the iceberg.

When we see an adult walking stick on our level it usually means it was blown down from the upper leaves of a tree or dropped to escape a predator.  Being lightweight, they usually survive the fall without damage.  If you try to pick one off a tree or the side of your house, watch how quickly it can drop.  This is just the beginning of its tricks.  Some stick insects can auto-amputate a limb to escape the grasp of a predator.  This is called autotomy and some species can regenerate the sacrificed leg over time.  Other species have defenses such as toxic chemicals, spines on their legs, or bright colored wings that they flash to startle a predator.

Our giant walking stick, Megaphasma denticrus, is the longest insect in North America.  It occurs in the southern and midwestern United States.  Males are rare, as few as one per thousand females.  In spite of these odds, finding a mating pair is common.  One reason is that once they mate, the male clings on for hours or in some cases days.  This behavior prevents other males from competing for the female's attention.  Some evidence suggests that it also improves the male's chances for successful offspring.  If a predator comes along, the male is more exposed and may be sacrificing himself for the cause. 

Some species of sticks like our M. denticrus  can reproduce by parthenogenesis, meaning that they don't require males to produce fertile eggs.  These offspring are all females so genetic diversity still rewards male fertilization in the long run.  Eggs are dropped randomly on the fall forest leaf litter and the young nymphs are left on their own to emerge in the spring, lighter colored miniatures of the adults.

Some stick insect species have an fatty treat on the end of their eggs, called a capitulum.  Ants will pick up these eggs and take them to their nest where they eat the treat without harming the egg, a behavior called myrmecochory.  In the spring the stick nymph chews its way out of the egg and crawls out of the nest to find a nice juicy leaf.

Indian Walking Stick - UC IPM
Finally, there are invasive species of walking sticks in California.  The Indian walking stick, Carausius morosus, has become popular in the pet trade and schools.  They are parthenogenic, producing offspring without mating.  Since they too shed the eggs on the ground, they get spread when a cage is cleaned.  They can be identified by the distinctive bright red markings on base of their front legs.




More from the rabbit hole?
Check out the Lord Howe Island stick insect, called the "rarest insect in the world" and known locally as a tree lobster.  The story is at this NPR Link.

A giant walking stick is "running" in this video.

Walkingstick or walking sticks - which is right?  Most sources say walkingstick but since this is a common name there is variation, sometimes in the same article. 

Friday, December 29, 2017

Hackberry Birds

 
"You got a problem, Bud?"
We were visited by a flock of hungry robins this morning.  They were drawn to the dwarf hackberry tree off our deck.  I had used the bare branches to hold vine dream catcher rings I was spraying with silver paint last week, leaving some of the black berries glistening.  There were several dozen birds with a strong attitude, fluttering in and competing for the black fruit, only occasionally sampling the silver ones which they would then drop to the ground.

Fall drupes
Early summer drupes
Dwarf hackberry (Celtis tenuifolia) is a short glade adapted relative of the common hackberry, Celtis occidentalis.  The fruit is small but colorful, starting out a bright green, then orange, blending into red, ending up black in winter.  It is sometimes called a sugarberry but is actually a drupe, with a single large seed which makes up 90% of the volume.  The thin rim of flesh is sweet to my tongue even now though they are dry in winter.  The flesh is remarkably high in calories from fat, carbohydrate and protein, making the effort worthwhile for the birds.

Cedar Waxwing - REK
In the midst of the robin onslaught a lone cedar waxwing arrived, consuming one berry before being driven off.  Its black eye band resembles a mask, giving it a threatening look.  Unlike the robins that are scattered in the woods,  a flock of waxwings tend to attack one or two cedars at a time, stripping all the cedar berries (actually miniature cones), leaving the ground beneath covered with litter.

Robins gather in flocks this time of year and we have seen up to 50 clustered on the creek bank out of the wind, browsing for seeds.  They will scatter out, picking at the berries on the cedars surrounding our house on an overgrown glade.  If you look along fence lines on field edges you will see small cedars they planted while seated on their barbwire toilet.



I wonder if the robins attacking the silver sprayed drupes didn't get the flavor and therefore dropped them.  Who knows what toxins they might have consumed if eaten?  On the other hand, they may just not be into shiny things.

Tuesday, December 26, 2017

Mussels Lure Fish


Mussel with "crawfish lure" - Chris Barnhart
Dr. Chris Barnhart's videos are featured in a National Geographic posting.  While many in the Ozarks know him from his passionate support of the Butterfly House at the Springfield Botanical Center, his day job is in research on fresh water mussels and the methods of raising them in laboratories which takes him around the globe. 

Mussels are the Rodney Dangerfield of the rivers, getting no respect.  In a word association game, if you say "mussel" the usual response is "Zebra".  If you Google mussel images, you might think that mussels live only in pots on a stove.  And in real life, don't they just lay on the stream bed and suck up water?

Consider for a minute their family history.  Unable to move great distances, how can they be found upstream after floods?  The answer is fish.  They depend upon fish to raise their babies and deliver them upstream.  Their deceptive methods to entice fish into hauling their newborn around are described in this National Geographic link.

Mussel ready to grab a fish - Chris Barnhart
While most countries have fewer than 20 mussel species, North America has 300+ species.  Our Midwest region has 78 species but more than half are endangered.  So why should we care whether they survive?
  • They require clean water and their declining numbers are a red flag warning us about the health of our streams.
  • As filter feeders, they clean up plankton and silt, then become another link in the food chain; prey for raccoons, otters, herons and occasionally fish.  
  • They are sold to Asian industries to put into oysters as the nucleus to create pearls.
  • Mussels don't get cancer. Could their secret help us prevent cancer?
Mussels were important as a food source for Native Americans as evidenced by large shell middens along the Mississippi and Ohio valleys.  The shells were used as tools, decorations and trade items, showing up at inland sites.

Around the turn of the 19th Century, mussels were a major industry on the White River in Arkansas and southern Missouri, first as pearls and then for the shells as buttons.  Elmo Ingenthron described this period in The Pearly Waters, beginning with the "1891 finding of a 14 grain fine luster, pinkish-colored pearl which sparked a virtual stampede of pearl hunters into the river."  The popularity grew as everyone "dived in" so to speak and by 1903 the market made $125,000.  Meanwhile several factories popped up along the White River, cutting button blanks to be sent for drilling elsewhere.
Crow-hooks- Stateoftheozarks

"Shellers jury-rigged lines of heavy “crow-hooks” stretched across long bars which were then trolled through the clear, cold water behind john boats. Mussel species snap shut when provoked and crow-hook trolling proved an efficient method of collection. The mussels would close on the hooks and be hoisted up. Onshore, buyers steamed the mussels and removed the innards (which were then sold as hog feed). The cleaned shells were taken by barge to local button factories. Early records suggest as many as two million pounds — and an estimated eight million of these mussels — were pulled from the White River each year." Stateoftheozarks.net

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Thursday, December 21, 2017

Cordyceps


When Christmas approaches, the woods are cold, the leaves are gone and new findings in nature are fewer.  Digging back on stories I had forgotten, I came across a picture Mark Bower sent me in September that got lost in the start of school.  This is a moth cocoon that has been parasitized by a Cordyceps militaris fungus.  The pupa has been virtually replaced by the white fungal mycelium and  the fruiting body, aka mushroom, has emerged.

If you or I came across this in the wild, we would likely pick it off at ground level to look closely at it.  The trick is to know to dig into the ground and find the substrate.  C. militaris attacks the pupa of moths that are buried in the ground.  The mycelia infiltrate it, keeping it alive to feed it until it eventually consumes the innards, and then sends forth its fruiting body above ground in a burp.  By digging instead of picking, Mark was able to preserve the whole fungus.


On the forest floor
Going back into my files of topics, I found the picture of another one above, that Mark sent me last year.  It too got lost in the files, but here is what he said about it.
"The first picture is how I found it on the forest floor. I dug it up and the cylindrical structure became apparent. This fungus feeds on the larva or pupa of butterflies and moths (and others?). It must not be too particular. The next photo (below) shows the insect structure cut longitudinally."
Pupal remains cut lengthwise

He goes on to explain that this fungus is an ascomycete. The spores are ejected from the pimply perithecia in the magnified photo on the right.



If this reminds you of a scene from Alien where John Hurt develops the mother of all cases of indigestion, remember that this fungus has been doing this thousands of years before movies thought of it.  While the message in the movie is 'what you eat could eat you', in the Orient this fungus is consumed as a medicine!  As explained in www.eco.nsc.ru:
"The use of the fungus C. sinensis, growing on caterpillars of ghost moths in the mountain regions of China, Tibet, and Nepal, as a medicine was reported in 1082. Tibetans call this fungus Yarsa-Khumbu, which means “summer herb — winter insect”; Chinese, Dong chong xia cao, i. e., “the herb that eats caterpillars”; and Nepalese call it Jivan booti — “the herb of life”.

Indeed, the fruiting bodies of C. sinensis contain unique substances — the polysaccharides that display immunomodulatory, antibacterial, and antiviral properties. This fungus is considered the most valuable remedy for asthma, hepatitis, vascular and renal diseases, liver cirrhosis, cancer, and many other serious diseases. A number of researchers have demonstrated that other fungal species belonging to the genus Cordyceps display analogous pharmaceutical properties."
There are some preliminary studies on the medicinal potential of Cordyceps which may yield future therapeutic agents, but meanwhile I would suggest that you "don't try this at home".

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Further reading:
Fungal Parasites of Animals
Cordyceps militaris at mushroomexpert.com.
Medicinal uses of the mushroom Cordyceps militaris: Current state and prospects

Saturday, December 16, 2017

Christmas Break


Usual activities seem to get pushed aside around Christmas, and my energy for new blog topics fades.  Fortunately there is an answer for this, bordering politely on the edge of plagiarism..... borrowing from other more talented sources.  Hence, here is today's offering.

First, a favorite blog of mine is the Bug of the Week written by BugLady from the Field Station at the University of Wisconsin.  She too has a case of the holiday doldrums but addressed it by re-posting this story of flying spiders found at altitudes as high as 15,000 feet!  These are newly hatched spiderlings and they aren't flapping their little legs but rather launching on silken strands that serve as kites.

Let me warn you about time lost following her links.  We went "down the rabbit hole" chasing her reference to "Anna Botsford Comstock, and her wonderful Handbook of Nature Study."  Google searches, taking us farther and farther away from completing our blog, led to this Wikipedia article on the fascinating Anna Botsford Comstock.  Then we found the PDF of the book on line.  The book's section on wildflowers, starting on page 486 is a good place to start sampling, but don't say I didn't warn you about losing track of time.

Monday, December 11, 2017

Mating Snails


White-lip globe snail

We encountered these snails clinging onto a sycamore leaf in the midst of mating last week.  Chris Barnhart identified them as  white-lip globe snails, Mesodon thyroidus, members of the Polygyridae familyThey are land snails, species that left the water and lost their gills long ago when they evolved into air breathers. They are equipped with lungs and are therefore called pulmonate.  In case you have forgotten some of your snail anatomy I've attached a reminder below.
When we first saw this pair there was a bright blue band connecting them, their intertwined copulatory organs filled with their blue blood.  By the time I had my camera out they had separated, leaving their pale white organs dangling, but Alan Cresslor caught a pair like ours in flagrante delicto in the photo below.  The whole subject of snail reproduction gets very complex and I won't get into their love darts which are not fodder for a family blog like ours.

Mating white-lip globe snails - Alan Cresslor
Most land snails are hermaphrodites, equipped with both male and female organs.  Some species may reproduce without mating but other species like our M. thyroidus transfer their sperm to the vagina of another snail via the penis seen above.

We kept these snails long enough to get them to the WOLF School.  I followed one attempted escape as it climbed the wall of a small plastic aquarium.  In the midst of its journey it deposited a small green pile, then crawled over it.  The opening on the left (the snail’s right) is the breathing pore (pneumostome).  Its anus is located in the pneumostome!  We are talking bad breath!  Chris Barnhart tells me that "they often stand on the feces like that. I’m not sure why, but it might have something to do with recovering salts. They can absorb ions through the foot."

When you move as slowly as a snail, you can't be too particular about what you eat.  Most tend to be omnivores eating plant material, fungi, and anything in their path.  Some snails are even predatory!  Our little friends have been rasping away at the tops trimmed off of our sweet peppers.  They use their radula, a tongue equivalent with rasp-like teeth built for scraping the surface of food into the esophagus, but even here there is tremendous differences between species.
"The radula is a membrane covered with series of tiny teeth made of chitin, so it is coarse like sandpaper. The shapes of these small teeth are used to help identify some snail species. However, the teeth of the radula should not be confused with denticles in the aperture of a snail’s shell, which are often referred to as “teeth” as well.
The radula is drawn over a ridge of cartilage (the odontophore), somewhat like a chainsaw chain slides around its bar - though it moves back and forth rather than in a circular motion. Bits of food are broken off and drawn into the snail’s esophagus for digestion. Several bouts of crawling and feeding can occur during an outing.
If you allow a larger snail to crawl on your hand, you may be able to feel it “taste,” or rasp, your skin – the sensation is painless, but feels like a cat’s licking."  Carnegie Museum of Natural History

Don't put snails on the table cloth.
And now the slime.  It was best demonstrated on a colored tablecloth which one of our snails escaped to after climbing out of the aquarium.  Note to self:  Close top of aquarium to maintain domestic harmony.  Since leaving its aquatic origins, preservation of its water has become critical.  A snail's slime is essentially mucous composed mostly of water protecting it against evaporation.  The slime can serve as a lubricant or an adhesive.  When one of our snails tried to escape across the table it left a trail of adhesive slime that lifted the tablecloth when I tried to pick it up.   The chemistry can be far more complicated as in the common garden snail, Cornu aspersum.
In the case of Cornu aspersa, the discharge is composed of synthesized products from various types of secretory glands. These are all single cell glands found in connective tissue and secrete their products via pores that pass between the epidermal cells. They are of various shapes and usually have a long excretory duct. There are eight different types of secreting glands. Four of these different types of mucus secreted protein, calcium, pigments, and lipids.  Wikipedia
There is a sinister side to little snails like this.  Brainworm, Parelaphostrongylus tenuis, is a parasitic nematode commonly affecting the brain of white-tail deer.  The worm lays eggs in the meningeal tissue of the deer which pass into the lungs where they hatch.  The larvae then are coughed up and swallowed, and eventually passed out in the feces.  Slugs and snails pick up the larvae which live in them as intermediate hosts until the mollusks are eaten by deer, starting the cycle again.  They pose no risks to the snail or humans.

The End
Our snails are now living under a large rotting oak log, hopefully rasping away at fungal hyphae and sharing the story of their visit with the 5th grade class.  You can watch the snails move at a snail's pace x4 here.



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Chris Barnhart shared this extensive set of photographs of Sonorelix sp. desert snails mating.

Resources
The Living World of Mollusks
More on the White-lipped Globe Snail is in this
University of Florida link.
Gastropod reproduction
Snail anatomy, the source of the diagram above.