Lyme Disease- Mice or Deer?

Deer are commonly thought to be a major factor in Lyme disease, harboring the organism until it infects ticks which transfer it to humans.  It may be that deer are getting a bad rap.  An article in nativeplantwildlifegarden.com suggests that it is more a story of mice and men.

Dr. Richard S. Ostfeld of the Cary Institute of Ecosystem Studies has been doing research into the  factors that have contributed to the rapid increase in Lyme disease cases.  As the article says,

"Ostfeld and his team have found that the primary culprit in the skyrocketing increase in Lyme disease cases is the reduction of biodiversity due to habitat fragmentation and destruction and its impact on the number and composition of host species for ticks.  Perhaps deer are not the primary villains in the Lyme disease story as we’ve been lead to believe.

Dr. Ostfeld has found the number of infected ticks is directly related to the diversity of host mammals, including white-footed mice, chipmunks, squirrels, catbirds, opossum, fox and deer, that the ticks can feed on which is directly related to habitat biodiversity.

The risk of exposure to Lyme disease is lower in a large forested area than it is in a fragmented habitat like a small wooded lot or our own back yards. That’s because small mammals that thrive in large numbers in these fragmented habitats – mainly white-footed mice – seem to infect a large number of ticks with the Lyme disease pathogen.

Mice encounter lots of ticks. In addition, they do a poor job of grooming off ticks so they have a high rate of permissiveness and a high propensity to infect those ticks that remain with the Lyme disease pathogen, or what Ostfeld calls reservoir competence. As you can see from this table, white-footed mice, and to a lesser degree chipmunks, are apex hosts for Lyme disease."

The tables and a more complete description are available at nativeplantwildlifegarden.com. For more in-depth information, there is also his lecture Biodiversity Loss and the Rise of Emerging Infectious Diseases on youtube.com.
Addendum
This mouse-deer connection is also an excuse to work in a totally unrelated true story.  This sounds like a tall tale by our friend Buck, but this one is true.

Pregnant mouse deer

We had the privilege of seeing a mouse deer during a night hike in Kalimantan Province of Borneo years ago.  Finding my picture would require an archeological expedition into the frightening "closet of  shoe box negatives," so I had to use this one from the article below.  For those of you who don't know what a negative is, I would recommend Googling "Kodak extinct species."

Mouse deer are members of the ancient ruminant family Tragulidae.  They are the smallest of all ungulates, standing a maximum of 14" tall and weighing in at less than our miniature schnauzers.  More incredibly, they not only swim but dive a under water to escape threats as described  in this BBC story.  More at http://www.squidoo.com/mousedeer.

Postscript
The earliest case of Lyme disease has been discovered.  Oetzi, the Iceman, a by now famous 5,300-year-old body discovered frozen in the Eastern Alps in 1991was found to have the Borrelia burgdorferi bacteria which causes Lyme disease.   

Oldfield Mystery

Animal or plant?- Click to enlarge

Our friend Georgia sent me this picture from her picnic table in Oldfield.  As a game of Stump the Master Naturalist, it was like going one-on-one with Jeremy Lin, not much of a contest.  I was pretty sure it wasn't mineral but beyond that I was out of my depth.

Chris Barnhart to the rescue!

"It’s a Crowned Slug Caterpillar, Isa textula.  The whole family Limacodidae has the most amazing caterpillars.  It would be great if we could raise some of these for the Butterfly House - they feed on oak."

Adult Moth- UGA 1430099

This dramatic larva becomes a rather generic looking moth, the Crowned Slug Moth or Skiff Moth, Isa textula.  The caterpillar feeds on trees such as oak, cherry, maple, and elm.  Don't let the soft fluffy appearance fool you.  Just like many other caterpillars, these are stinging spines and hairs, so if you plan to bring one to the Butterfly House, use a no-touch technique.

"First Butterfly of 2012"- Kevin Firth

Butterfly season will be upon us soon.  We are already seeing more butterflies of winter such as the Goatweed Leafwings which spend the cold nights as adults, tucked under loose tree bark.  Like some of us, Kevin Firth's Mourning Cloak to the right seemed to enjoy flitting about on a warm day.

Also warming up are the plans for the Bill Roston Butterfly House this year. If you are interested in helping out, a volunteer orientation session is scheduled for April 18th, 5:30 or April 21st, 9:30. Contact number is the Botanical Center, 417-891-1515.

Male Spider Amputation

Spider with black pedipalps- Wikipedia

Spider sex is a dangerous game.  All spiders are predatory, and many eat other spiders including their own kin.  The infamous Black Widow and many other species may respond to a male's sexual overtures by over powering and eating him, which gives a whole new meaning to a "dinner date."

Spiders have a pair of structures behind the mouth called palps.   Male spider's palps are specialized into sexual organs.  They use these palps to transfer and store sperm from its gonads.  Once one successfully "hooks up" with a female, the male inserts his palp into her sexual organ to transfer the sperm.

You would think that having survived the courtship approach to the female, life would be good.  For some orb spiders, when the male withdraws or is pushed away, the palp amputates and remains in the female.  The hard hearted female in some cases may then dine on her mate.

Insects, like other animals live to reproduce their own progeny.  Like humans, the females can be sure that the young are their own genetic stock, the males, not so much.  Some species like the walking sticks hang on in prolonged intercourse to prevent other males from adding their sperm to the mix.  Others seal the female opening after introducing their sperm to prevent further mating.  This would seem to be a possible reason for the detached palp.

A new study in livescience.com shows that for at least one variety of orb spider, there is more to this event.  Researchers studied the orb-web spider Nephilengys malabarensis which has detachable genitals.  They studied 25 pairings under controlled conditions.  In 88%, the male's palp was detached and remained in the female.

Now is where it gets really kinky.  The scientists observed the females with the detached palp in place for various periods of time up to 20 minutes.  Then, as Dave Barry says, "and I am not making this up," they removed the palp and counted the remaining sperm.  What the female thought about the observation or the removal was not recorded.

They found that 30% of the sperm were transferred before the palp was broken off.  If it remained in place for 20 minutes, 85% of the sperm were transferred.  In other words, like the old Timex commercials said, the palp "keeps on ticking."

Not only does this allow for a 200% increase in sperm donation, but in many cases the surviving male becomes more aggressive and guards the female against other males, increasing his chance of posthumous fatherhood.  Meanwhile, in a laboratory setting it took the female seven hours to get the palp out on her own.

In addition to other spiders, male scorpions, fire ants, ground beetles and cephalopods are known to amputate their genitals.  I assume that scientists in the future will be watching for more "breaking news."

Evolving with Toxins

Spotted salamander- Steven Brady, Yale

Fellow Master Naturalist Bob Korpella regularly writes about nature in the Ozarks in his Freshare.net site.  One of his stories gives us hope that evolution moves faster than we thought.  As we foul the environment, at least some species are evolving to adapt.

Steven Brady of Yale* studied spotted salamanders living in roadside ponds that get wash off from the roads.  They contained concentrations of salt up to 70 times more than nearby ponds away from the roads.  A salamander's skin has several specialized features including secreting mucus which allow it to control its salt balance when in the water.

The road side salamanders have a higher level of deformities and a lower survival rate of their eggs.  Those that survive year after year are apparently evolving by natural selection to tolerate the conditions.  “The animals that come from roadside ponds actually do better—substantially better—than the ones that originate from woodland ponds when they’re raised together,” Brady said.

There must be something to the saying "what doesn't kill you makes you stronger." Read more in his story Road Runoff Spurring Spotted Salamander Evolution.
 *  Yale School Forestry & Environmental Studies 

Click to enlarge

Now for a quiz- Animal or Plant?  What is it?  (The answer is coming to this blog soon)

Now That's Small!

from PLOS

Scientific American has a report on the world's tiniest chameleon, and is it cute!  As you can see, it would have trouble climbing over a hangnail.  When not hanging onto a researcher's finger it can be found, with difficulty, climbing "up" on branches to a dizzying height of four inches.  Since it hunts in the day, it is easy to pickup at night while it is sleeping.

This midget now goes by the name Brookesia micra.  Scientists have always felt that there was a limit as to how small a vertebrate with a compound eye could be, but each time they reach it they find one smaller.  These chameleons are found on the island of Madagascar where they are threatened by habitat loss, deforestation and  probably anything larger than a baby frog. 

Microfrog- Christopher Austin- LSU

Speaking of frogs, the world's smallest frog happens to be the new species reported by Christopher Austin from Louisiana State University in PLOS.  It is now officially Paedophryne amanuensis, a name too long for it to wear on a name tag.  It currently holds the title of the world's smallest vertebrate.

There is more on this and other microfrogs in livescience.com.  If you have a few minutes to spare you might also want to thumb through Forty Freaky Frog Photos.

Deer Antlers

The Great Hunter

Barb was quite excited a few years ago after her first successful hunt.  And the good news is that no deer were harmed before the taking of this picture.

Shed hunting is a quiet sport and a good way to spend a winter day.  Bucks start to shed their antlers in December, with the latest falling off by February.  The blood supply to the base of the horns decrease and the weakened junction causes the antlers to fall off.  Immediately the buck starts to grow next year's rack.

Hunting for sheds is a sport for many people.  Antlers are prized also by many rodents because of their calcium content, so it is usually first come, first served.  Finding both undamaged antlers at once is as good as it gets.

Many shed hunters are competitive, putting out game cameras to locate the areas frequented by bucks with trophy racks.  There are hunting lodges that cater to shed hunters and even people to train your dog to find them.  There are lots of tips for hunting at Trophyhuntingobsession.com.

The size and shape of a deer's antlers is very important in the world of hunters.  Most of the articles about antlers have to do with measurement and the number of points.  I recently came across an interesting article from the Missouri Extension that could be titled Everything a Naturalist Needs to Know about Deer Antler Development.  Reading it is the next best thing to walking in the woods and its a lot warmer.

Plants Have Rhythm

Tommy LaVergne/Rice University)

If you've ever experienced jet lag, you have felt the altered ticking of your biological clock, a phenomena known as circadian rhythm.  The many effects on our behavior and sense of well being are well known.

Plants and animals have circadian rhythms as well.  Ever since one of Alexander the Great's captains noted the repositioning of leaves during the day, we have been aware that plants respond to daily cycles.  Later studies showed that the rhythm continues even when the plant isn't exposed to the sun.

An interesting article and video posted by our Master Naturalist Bob Korpella at freshare.net describes research at Rice University on circadian responses of plants which produce defenses against insect attack.  The cyclic release of a plant hormone makes a common cabbage looper caterpillar leave the plant alone.  Sounds a little like an attack of botanical PMT.

Watching is for the Birds

Bluebird chicks- Day 1

Francis Skalicky reminds us in today's News-Leader that it is Time to make bluebirds welcome.  Bluebirds begin building their nests for their first broods from mid-February through March and will be apartment hunting in your neighborhood.  It is therefore time to clean out your bluebird boxes to have them ready to rent.

He describes what they are looking for: a nice neighborhood with preferably short grass, scattered trees to perch on, and a  sunny exposure, preferably not due south which heats the home too much in summer.  Nearby insect playgrounds are welcome,  but don't worry, they will find them on their own.

Supper Time!

In addition to their insect hunting, they provide lots of entertainment.  It is important to check the boxes every few days to clean out wasp nests or other unwanted visitors and to clean the nest after the chicks fledge.  The fun part is watching the chicks hatch and grow.  A tapping on the box will allow mom to get away to a nearby tree where she will watch you, then return when you leave.


Another opportunity to watch birds and advance science is the Greater Backyard Bird Count (GBBC) which starts this Friday, February 17th and runs through Monday the 20th.  It is simple to do, requires no technical expertise and is easy to report on line.  You can do it anywhere on any or all 4 days and it requires a minimum of 15 minutes of your time.  Click on this web site and watch the instructional video.  Then on the days you participate, simply go to the GBBC website and begin.

Evolution of Rivers

Bull Creek- click to enlarge

I hadn't given much thought to how our rivers were formed until I came across an article in Livescience.com.  It turns out that a major factor in their shape and size over millions of years was the evolution of plants. 

Rivers were pretty lackluster affairs 500 million years ago in the Cambrian period, straight, wide and extremely shallow, leaving no discernible banks in the geological record.  How wide were they?  Some estimates are that they were 1000 times as wide as they were deep.  There was no mud yet to support banks.

The first primitive plants developed around 470 million years ago around the time of the development of mud which is more cohesive than sand and gravel.  This wasn't a coincidence as plants are instrumental in the formation of mud.  Acids they produce break down rock and later the development of roots causes physical cracks.  Plant death added to the mud, producing soil.

Soil not only binds the particles together to create firmer banks, but it facilitates the growth of plant roots which holds acts as reinforcement.  When this evolved, we see evidence of meandering streams appeared around 416 million years ago, providing habitat for evolving fish and insects.

By planting trees along streams we enhance the riparian corridor, just our humble way of restoring what nature accomplished millions of years ago before the attack of our plows.

Birds Identify Trees

Bluebird- Mike Onyon redorbit.com

It appears that birds can select their trees to feast on just like we pick a nice restaurant.  According to an article at sciencedaily.com, birds are able to pick the right tree species to increase their chance of finding a great meal.  The study reported in the American Naturalist showed that chickadees and other birds select the type of trees that they dine in as well as their targeted caterpillar variety.

Many caterpillar species have a limited number of tree species to choose from as their obligate food source.  In addition, their mother's choice of the tree where she lays the egg affects their success.  The healthiest tree would feed the greatest number of juicy caterpillars.  Apparently birds figure this out and select their tree species, so the individual caterpillar's survival odds on a great dinner tree are much smaller.

That being said, there are two competing strategies.  Eating on a less desirable tree may produce smaller and less healthy caterpillars with a lesser chance of successful survival.  Dining on the healthy tree may increase the gastronomic odds but at the risk of increased predation.  Caterpillars living on an nice juicy black cherry had a 90% chance of being eaten by a bird.

Although the nutritious cherry tree leaves produce "fat cats" (think 5 star Michelin guide) we don't know which strategy produces the most adults in the long run.  But at least they don't have to go far for a good meal.  As the saying goes, "Fat cats don't hunt."
redorbit.com

Ticks in February

Adult Deer Tick- Wikimedia

An article at livescience.com discusses the downside of the balmy days we are having this winter.  Barb and I have found at least three reasons to look forward to a good hard freeze, and all of them had 8 legs.  Along Bull Creek, one Lonestar tick and two deer ticks have crawled on us this week, and those are just the ones we saw!

We are not alone in this warm spell.  The Northeastern United States is having its fifth warmest December on record.  Minneapolis temperatures first reached zero on January 19th, only seen once before in over 140 years.

What effects can we expect from this?

• Mosquitoes, ticks and fleas may be out earlier (amen!) and even be more fruitful in multiplying.
• Plant pests may be out earlier and have a greater impact this year.
• Plants may come out of their winter protection and bud earlier.  This always raises the concern about a late freeze killing off the buds and their fruits.  The same applies to frogs and salamanders which might end hibernation and then face a killing frost.

As Patrick Byers, horticultural specialist for the University of Missouri Extension points out in the latest edition of Greene Magazine, a late freeze may well kill off many of the emerging pests and their eggs and larvae which are freshly hatched.

Meanwhile you had better get out now and enjoy the warmth while you can.  But remember, that faint crawling sensation might just be Rip Van Tickle waking up from his winter nap.

Rat Zombies?

Research described in Sciencedaily.com suggests that a parasite named Toxoplasma gondi which lives in a rat's brain alters the behavior of infected rats, making them lose their fear of cats and possibly even seek them out.

Cats are the main host for Toxoplasma which can only reproduce in a feline's body.  To spread its species in absence of legs or wings, Toxoplasma requires a way of getting more cats to ingest its offspring.  That is where the rat comes in.  Toxoplasma spreads by infecting hosts which  are eaten by cats.

The Toxoplasma organism lives benignly in the brain of rats and other animals, using its host for just enough energy to survive, generally without harming the host.  It is in its best interest for an infected rat to remain healthy, that is until it encounters a cat.  Then it ends its friendly relationship, encouraging the rat host to get eaten.  This is where the zombie comes in.

The new study by Patrick House of Stanford University suggests that the Toxoplasma infected brain causes the rat to lose some of its fear of a cat while maintaining its normal anxiety and fear brain responses to other predators.  The male rats brain also shows stimulation response to rat urine odor in an area usually activated when a female rat approaches.  The result is similar to the fate of a turkey gobbler responding to a hunter's call.

Patrick House summarizes his study in this Stanford interview.  A detailed description of the Toxoplasma life cycle, which includes frequent human hosts is at  stanford.edu/.

If you found this interesting or are a naturalist who likes Stephen King stories I have just the book for you.  Parasite Rex by Carl Zimmer has been reprinted in paperback and covers the lives of various parasites with clarity and an occasional dose of humor.  He summarizes this type of parasite behavior as follows:

"Simply living within another organism - locating it, traveling through it, finding food and a mate inside, altering the cells that surround it, outwitting its defenses - is a tremendous evolutionary accomplishment.  But parasites such as Sacculina do more: they control their hosts, becoming in effect their new brain and turning them into new creatures.  It is as if the host itself is a simply puppet, and the parasite is the hand inside."

You will be startled by the number of parasites that are around and even in us, and their influence on behavior.  Then try to get a good night's sleep.

More on Toxoplasmosis and suicide at Scientific American.

Mosquitoes Keep Their Cool

New research on how mosquitoes keep their cool is reported in sciencecodex.com. 

Mosquito- Wikimedia

If you have ever swatted a tiny mosquito and seen the blood left on your skin, you can imagine how much blood they can stuff in their body.  However, your warm blood creates a risk of overheating in this coldblooded insect.  You probably aren't feeling any sympathy yet for this poetic justice.

The study which was reported in Cell Press helps explain how the mosquito handles this heat stress.  A mosquito doesn't sweat like we do or pant like a dog.  Insects generally control their temperature by extruding fluid such as nectar or sap.  The mosquito puts itself at great risk of a crushing blow when it is sucking the blood it needs to reproduce. 

To cool itself, it apparently has to ooze out a little of that blood.  Using a heat sensing camera, researchers determined that the mosquito's head was the temperature of blood while the body remained cool.  The cooling was due to the loss of liquids out their backsides. Learning how this is controlled could be of practical value if a method of blocking or delaying the excretion of fluid could be developed.


The microbes on your skin determine how attractive you are to mosquitoes, which may have important implications for malaria transmission and prevention, according to a study published Dec. 28 in the online journal PLoS ONE.  Human sweat is odorless to our nose, so the mixture of microbes on your skin help determine your special body odor.

Eurekalert.org reports that researchers, from Wageningen University in the Netherlandsstudied the Anopheles gambiae sensu stricto mosquito, which plays an important role in malaria transmission.

"They found that individuals with a higher abundance but lower diversity of bacteria on their skin were more attractive to this particular mosquito. They speculate individuals with more diverse skin microbiota may host a selective group of bacteria that emits compounds to interfere with the normal attraction of mosquitoes to their human hosts, making these individuals less attractive, and therefore lower risk to contracting malaria.  This finding may lead to the development of personalized methods for malaria prevention."

The next time someone tells you that they always attract more mosquitoes than anyone around them, you might suggest that they try changing skin bacteria.  On the other hand, you might not.

Where Did I Put That Nut?

Squirrel Proof Bird Feeder

When a squirrel buries acorns and then forgets them, it is also planting little oaks.  Good for trees, bad for squirrels.  They accommodate for this loss just like Walmart, by volume.  So can a squirrel remember where it hid a nut?

The first answers on the internet are mixed.  Many web sites say "No," they locate the nuts by smell.  It turns out that this is only partially right.  A 1991 study published in PDF found evidence that they could locate the nuts they buried.

"Captive squirrels were released alone into an outdoor arena, where they cached l0 hazelnuts each.  After a delay of 2, 4, or l2 days, each squirrel was returned to the arena and tested for its ability to retrieve nuts from its own cache sites and from l0 cache sites used by other squirrels. Although each squirrel's own caches were close to the caches of other squirrels, the squirrels retrieved significantly more nuts from their own sites than from sites used by other squirrels after all delays  The retrieval accuracy of the squirrels under these conditions indicates that while grey squirrels can locate buried nuts by their odor, they can also remember the individual locations of nuts they have buried."

Squirrels use a system of triangulation to remember where they have hidden their food. A study at the University of California Berkeley show that they triangulate the location of hiding places using what we would call "landmarks." While the human brain might be able to remember 4 or 5 triangulations to locate something, the tiny squirrel brain can remember 300 to 400 triangulations to locate the food they have hidden.

Even more amazing is these backyard bandits ability to get to illicit food sources such as bird feeders and vending machines.  This 2007 British video is well worth a watch.

More on squirrels but storing strategies is a this link.  They handle selected acorns differently, discussed here..

The Temperatures, they are a Changing

When we talked to people about our new southern Missouri home almost forty years ago we would brag that there was an occasional day in January when you could play tennis outdoors in fifty degree weather.  It seems this year we have a lot of them, and some days you would play in shorts!  A possible reflection of this trend can be seen in the new USDA Plant Hardiness Map.

The map is used by gardeners to select plants that are best suited to the local climate, as described by temperature range.  This is the first revision since 1990.  Although it is not a guide to climate change as such it does show some area of significant changes over the last 20 years.

As described in USA Today, the changes are not dramatic with none over a half a zone.  Most of the changes show a warming to the north.  In the words of gardening consultant Charlie Nardozzi:

"If you want to look at what might be the most politically correct thing, you can say something's happening.  But the climate is changing. Spring is coming sooner and lasting longer. Fall lasts longer, and overall the weather is so much more erratic now."

While these designations are accurate generalizations, local landscape can make a difference which the map cannot describe.  Our Bull Creek valley runs north-south with fairly steep sides.  The sun hits it late and goes down early behind the hills.  The evening temperatures are between 5-10 degrees cooler than the surrounding uplands.

Meanwhile, Matt Ridley has an interesting take in his Wall Street Journal article,
Are We Holding a New Ice Age at Bay?  He points out that even considering the Little Ice Age (1550-1850) our 10,000 years of developing civilization has occurred in an unusually warm spell.  Temperatures like ours have occurred in less than 10% of the time over the last one million years.  Indeed, one theory is that the unusual warmth allowed our predecessors to develop agriculture, the first step in civilization.

He discusses some of the hot and cold history of our planet and the theory of some that the current warming may be postponing the next ice age.  Before you run out and buy a heavier coat, note that experts are talking about the next 1500 years.  As with all climate theory, it is interesting but nothing to hang that heavy coat on.