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.