Nature Blog Network

Friday, January 23, 2015

Foam on the Creek

Foam on Bull Creek
When we first started hanging out on Bull Creek, I was concerned about the collection of foam I would find in eddies beside rapids. This eight mile section of the stream is designated as one of only a few Outstanding Water Resource areas in Missouri. Calling the MDC, I learned that foam can be a normal finding on the cleanest of streams.
Foam on the shoreline of a lake, created by wave action - Photo from The Waterline
David Casaletto just sent me a link to his story from on foam from Ozark Water Watch describing the scientific basis of foam creation on water.
 "On lakes, in bathtubs and in mugs of beer, the cause for foam is the same. Agitation at the surface causes air to get under the surface film of the water. Weakened surface tension is unable to force the air out, but rather keeps water wrapped around a volume of air, creating a bubble. If this happens for long enough, foam is created. On lakes, the agitation is usually due to wind, and the resulting foam will collect on the downwind side of the lake. In streams you will see the foam in eddies or floating downstream, and it is created by the flow of the water disturbing the surface film." 
The quote above is from the Waterline which goes on to describe in detail how foam is formed.  It describes the relationship of surface tension, aeration, and particles in the water to foam formation.  Not all foam is benign as organic compounds from decomposing plant or animal matter and other pollutants can make foam appear more commonly.  Rather than attempt an explanation, go to the Waterline story for details.

Ozark Waters is a valuable newsletter which you can subscribe to electronically for free at this website.

Tuesday, January 20, 2015

Intelligent Slime Mold

Arcyria cinerea- Mark Bower
When I wrote about slime mold in a November blog, I planned to followup with this story of intelligent slime mold.  Since then I have come across even better resources.
Physarum polycephalum
Mark Bower has created a book on Valley Water Mill slime molds, now available to see at the Watershed Center.  You can see some of his pictures in this Flickr album.  Looking at these pictures, it is hard to remember to the naked eye view of Physarum polycephalum above, single cell creatures smearing the tree bark are the same as the beauties pictured below.
Physarum polycephalum close up- Mark Bower
Physarum polycephalum is a lab rat, a cooperative slime mold that has been studied in all ways imaginable and new ways daily by scientists, engineers, neurobiologists, artists, and now even amateurs. There are 200+ Youtube videos of Physarum polycephalum over 200 Youtube videos of P. polycephalum running mazes, creating road maps, demonstrating other collective intelligence and even making music.

Rather than wading through all of these, just watch this TED talk on slime mold.  The speaker even shows interested citizens linking up to reproduce the movements of slime molds.  And friends say I have too much time on my hands!

Thursday, January 15, 2015

Photosynth of Round Spring Cave

Round Spring - mostreamteam25.wordpress.com
Melvin Johnson sent out a video of Round Springs Cave which is spectacular. It is a "photosynth" video which takes you step by step through a 17 minute virtual cave tour from the outside in. The spring flows under a natural bridge to join the Current River.  This National Park Service site provides information on visiting the site.  Below is the description from http://www.mospeleo.org:
"The spring rises in a circular, collapsed cavern, then flows through a natural tunnel before forming the spring branch. Round has the largest variance in measured flow from a minimum of 6.5 million gallons of water a day (mgd) to a record 239 mgd, or a maximum 37 times larger than the minimum. Nearby Round Spring Caverns, has an interesting geographical relationship with the spring, since one arm of the cave points almost directly to the spring.

Round Spring was extensively used by native peoples in prehistory, and was the site of an early 1800's gristmill. About a mile downstream was the original location of Eminence, Missouri, which was destroyed during the Civil War. The spring was located on the Eminence to Salem wagon road. Round Spring was the first site purchased for the state park system in 1924; nearby Round Spring Caverns was opened privately to tourists in 1932. Both the park and the caverns were incorporated into the Ozark National Scenic Riverways by 1972."
Round Springs Cave from the photosynth
Melvin invited us to "Take a 17-minute educational photosynth tour of Missouri's Round Springs Cave via the link below, especially if you've never been there or don't know about photosynths. Matt Bumgardner is with the Springfield Plateau Grotto and does an excellent job with photosynths. He has numerous photosynths of caves in southwest Missouri. Unlike other area caves, Round Springs Cave is still open in-season (summer) for public tours as DNR continues to feel the educational value is greater in-spite of "white nose syndrome."

So what is a photosynth and how does it work? Just like television and CERN's Large Hadron Collider - I don't know. Here is a description from the photosynth Wikipedia entry. In essence, it uses multiple still photographs from any digital camera and stitches them together into a moving image like a movie using a process developed by Microsoft with technology possibly pilfered from Harry Potter's alma mater, the Hogwarts School of Witchcraft and Wizardry.

Here is the photosynth of Round Springs Cave tour. It is pretty realistic so a word of warning, be careful you don't bump your head on the stalactites.

* Matt Bumgardner is president of the Springfield Plateau Grotto which meets at the MDC Springfield Nature Center the 2nd Thursday of every month at 7 PM.

Monday, January 12, 2015

Help From Our Friends

During the winter lull when most self respecting arthropods are either hiding or are the "usual suspects" lurking around our cabin, I start thinking about the last year and the lessons learned.  The tedious details of the otherwise pleasure of writing a blog include typos, errors and dead links.

In play mode with luna moth
Weed Warrior
First typos and editing content is cleaned up before publishing by my lovely and talented editor who works long hours for no money and little credit.  She does this in breaks from her job as "Bull Mills weed warrior," virtually eliminating all invasive plant species that she finds here.  There Barb, this is your pay for the year.



Jay Barber at work
We are grateful for the many friends and experts who help identify finds and provide resources.  They graciously review some of the blogs, correcting my errors before I make a bigger fool of myself than usual.  These include Chris Barnhart, Linda Ellis, Brian Edmond, Mark Bower, Charley Burwick, and a host of others, some of whom have asked to remain anonymous to preserve their reputations.  I also want to acknowledge Jay Barber, all the MDC team, and Patrick Beyers who support Master Naturalists and make this possible.  All of you are invited to Bull Mills at any time for proper if inadequate thanks.

That leaves the "dead links."  It is amazing how many valuable resources from professional and academic sites suddenly disappear from our "Resources" site in the upper right column of each blog.  Keeping track of them is a pain unless you have a Barb Clark.  She dropped out of the clear blue sky a few years ago, sending me a list of my dead links.  Since then, she routinely patrols the site, sending me dead links and suggestions.  You can't get that kind of service for money (at least from this cheap blog).
Barb Clark

While on the subject of Barb Clark and resources, check out her Internet Plant Sites, an extensive listing of resources on the web which had 10,014 hits the other day.

Barb Clark wrote back, "Hope you aren't retiring the blog."  No, not unless the FCC ever reads it and pulls the plug.

Thursday, January 8, 2015

January Phenology

January - Late season frost flower
Phenology - the scientific study of periodic biological phenomena

It is hard to get as excited about nature during a cold front with single digit wind chills.  Much of our observations are out the patio door, following the competition at our bird and squirrel feeders.  When the thermometer reaches 30, the wind dies down and the sun comes out, there is firewood to cut and cabin fever to burn up by getting out in the woods.


Frost flowers are largest with the first few freezing nights but the Verbesina virginica continues to "blossom" into the new year around the base of the plant as long as the roots haven't frozen.  I was surprised to see them recur vigorously with the last cold snap.  Late season frost flowers are frequently delicate strands rather than the wider ribbons of December.  Hoar frost and ice on the creek reward us if we get out before the sun hits it.

Although deer season wraps up this week, there is still the sport of hunting antler sheds.  With the leaves off the shrubs and trees, much more ground is visible, so the pale sheds stand out against the leaf litter.  Field and Stream lists 10 Ways to Become a Better Shed Hunter, a good way to get started.

Mourning cloak -  David A. Dawson, Master Naturalist
On warm winter days (remember those?) be on the lookout for the butterflies of winter.  Mourning cloak, comma, question mark and goatweed leafwing species emerge from under the bark, flying to stretch their wings and feast on tree sap and dung.  OK, feast may be too strong a word to link with dung, but at least they make a living.

For the botanically inclined, there is still plenty to see.  With the leaves off, the giant sycamores along the creek stand out like white ghosts against the sky.  They will occasionally serve as a perch for a bald eagle.


The bright red berries of deciduous holly, aka possumhaw (Ilex decidua) are scattered along the creek bottom, a welcome dash of color.  The berries are not  preferred by birds and small mammals, but since they persist in good condition through the winter, they serve as a source of emergency food.
WAHOO! They are out.
Our personal favorite is the wahoo, Euonymus atropurpureusIts fruit first appears as dark pink and four-lobed before splitting open to expose 4 arils, the fleshy covering of the seeds.  This fruit again isn't favored by birds - it is actually toxic to humans, so it persists through much of the winter before northern flickers, brown thrashers, catbirds, eastern bluebirds, and cardinals pick them off when other food sources dry up.  In addition to providing winter color, it gives up a reason to yell "WAHOO!" on a cold winter walk.

Monday, January 5, 2015

Frass Chains

Caterpillar at the end of its frass chain.  Horace Tan, Singapore
We recently described butterfly caterpillars whose intestines shot their frass (waste) long distances. At the other end of the waste disposal spectrum, there are larvae that use their frass as a defensive mechanism (frass chain) or a repellant against predators, called a fecal shield.

The caterpillar shown above is clinging to the end of a frass chain, a carefully constructed extension to a leaf petiole.  After chewing the rest of the leaf away, it builds an extension of frass and silk. Learnaboutbutterflies.com describes the process:
"Frass chains are constructed by many caterpillars, chiefly neotropical and Afro-Asian Nymphalidae. When not feeding, the young larvae rest at the tip of a chain constructed from their own droppings. The larva typically eats away the leaf tissue, leaving only the midrib intact, and then deposits a row of its droppings along the midrib. The droppings are bound together with silk. The line or 'chain' of droppings (frass) is then extended so it projects by about 2 centimetres beyond the leaf tip."  Watch the construction in this video.
The frass chain isolates the resting caterpillar from the leaf blade where ants and other predators travel in search of them. So far there has been no evidence that the frass itself has repellant properties. Horace Tan of Singapore describes this more fully in his pictures of the chocolate sailor butterfly.

Fecal shield on a tortoise beetle- Troy Bartlett
Some of the larvae in the leaf beetle family, Chrysomelidae apply their frass to their backs, creating a "fecal shield." This serves as a repellant because of the chemicals their frass contains. As described by academic.reed.edu:
"Fecal shields are a predator deterrence strategy. The beetles emit chemical compounds, such as saponins and steroidal alkaloids, in their feces that have toxic effects on predators. Authors show that generalist predator ants, such as Formica subsericea, will be disuaded from predating on beetle larvae with frass shields (Vencl et al. 1999). Once an ant has been in contact with a shield, it will move away from the larvae and begin to clean itself vigorously. There are a variety of chemical compounds in the beetle's feces that is obtrusive and toxic to the ant, including molecules such as steroidal glycoalkoloid derivatives, dioscin metabolites, fatty acids, and phytol derivatives (Vencl and Morton 1998)." 
In addition to turning hard, the fecal shields can be toxic. Similar to the monarch butterfly which ingests toxic alkaloids from milkweed, some leaf beetle species ingest and excrete alkaloids and other toxic metabolites from their host plants.

Wikipedia has much more information on fecal shields, including a video, graphic details about their consistency and the anatomical adaptations of how they deposit them on their backs. One genus' "larva constructs the shield by maneuvering its muscular telescopic and highly protrusible anus, or "anal turret" which is positioned dorsally on the back." This may be more than you wanted to know, but it serves to illustrate the wonderful diversity of nature.

Thursday, December 25, 2014

Mistletoe

Mistletoe in the wild - Freebigpictures.com
If you are looking at the blog on Christmas, you should have some reward so here it is.  A modern Christmas means, among other things, delayed flights, lost luggage and late bedtimes.  In our case it means all three, so our visiting family got to bed at 1:00 AM and are still blissfully asleep.

In lieu of writing something original, I am referring you to The Hemiparasite Season in today's New York Times.  The Times may not be your usual source for arcane biology, but trust me, this one is good, written by Olivia Judson*.  It is about tradition, 1300 species of mistletoe growing high in trees and how they live.  Eventually it gets back to scat.

Money doesn't grow on trees, but mistletoe does, so Merry Christmas, Season's Greetings or what ever rings your chimes.

*  Olivia Judson, author of  Dr Tatiana's Sex Advice to All Creation