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.