Best housemate ever: The Bold Jumping Spider

jumping-spider-eyes-by-opoterserwikimedia
What a face! The bold jumping spider’s large eyes provide keen vision. Its striking iridescent green fangs are likely for show. Photo by Opoterser, Wikimedia.

Most people don’t welcome spiders in their home, but once they get to know the bold jumping spider, they might change their minds. Don’t grab the nearest shoe to smash it, don’t be put off by its looks. Despite having eight fuzzy legs and large iridescent green fangs, this spider is a helpful, tidy housemate.

Bold jumping spiders are pretty big– their bodies are about a quarter to a half-inch long. And though they may look fierce, they are harmless to humans. According to Penn State entomologists, your chances of being bitten by one are “slim to none.” The rare accounts of jumping spider bites suggest the bite causes a reaction similar to a mosquito bite.

But if you are an insect, these spiders are the stuff of nightmares- a lion stalking you in tall grass, poised to pounce… Unlike many spiders that spin webs, sit back and wait for insects to fly into them, bold jumping spiders are active hunters. In fact, they don’t spin webs at all, which means they won’t leave dusty cobwebs in the corners of your home.

Jumping spiders hunt during the day in open areas, such as walls and windowsills, using their keen eyes to spot their prey. Unlike other types of spiders, they have excellent eyesight and an almost 360-degree field of vision. The bold jumping spider will pounce on any insect smaller than itself, including houseflies, mosquitos, small crickets and other uninvited guests in your home.

Once prey is spotted, jumping spiders sneak up within striking distance– which for a jumping spider is pretty far. They owe their astounding jumping ability to hydraulics, not solely muscle. These spiders are able to rapidly increase the internal fluid pressure in their legs, propelling themselves 10-50 times their body length and pouncing on their insect victims. US Track and Field athlete Mike Powell, who holds the world record in the long jump, can jump less than 5 times his body length– and that’s with a running start.

Though bold jumping spiders don’t construct webs, they do make spider silk. They use a single line of silk as a tether to catch them in case they make a bad jump, kind of like a rock climber’s rope or bungee jumping cord. The female bold jumper also uses her silk to make an egg sac and small “den” where she hides with the sac and then her spiderlings when they hatch.

Jumping spiders are fun to watch– scientists who study their behavior believe they are screen-shot-2017-01-24-at-3-17-06-pmvery “intelligent” given the size of their brains. Most jumping spiders perform courtship “dances.” A couple of years ago a video of a colorful dancing spider went “viral” on the internet. The species shown in the video was the Coastal peacock spider from Australia– a species of jumping spider, just like our very own bold jumper.

Like a good guard dog, the bold jumping spider defends your home from intruders, albeit very small ones. But unlike a dog, that sheds hair and tracks in dirt, jumping spiders don’t leave a mess. So next time a jumping spider has moves into your home, consider letting it stay. While it can’t be counted on to help out with the rent or mortgage, it may still earn its keep.

This article originally appeared in the Grand Junction Daily Sentinel in September 2016.

Advertisements
Best housemate ever: The Bold Jumping Spider

The scorpion’s softer side

northern-scorpion-by-meredith-walker
Northern Scorpion. Photo by Meredith Swett Walker

It is hard to think of a creature less likely to inspire warm, fuzzy feelings than the scorpion. They have pincers, an intimidating stinger, and are rumored to hide in shoes. Plus, they are hard to categorize and this makes humans uncomfortable. Is a scorpion an insect? Is it a crustacean like a crab? They look “crunchy”, “pinch-ey” and “stingy” all at once.

It turns out that the unlovable scorpion– which is neither insect nor crustacean– has a softer side. These creepy crawlies turn out to be caring mothers. Their venom may help scientists develop important medications. Though they cause many people to shudder, scorpions deserve a second look.

Scorpions are arachnids like spiders, and like spiders they have eight legs. The two front limbs that bear their pincer claws are technically “pedipalps,” not legs, and are not used in walking. While scorpions may look like an alien visitor from a chilling sci-fi film, they have walked the earth longer than almost any other animal. Scorpions evolved at least 430 million years ago, long before the dinosaurs. In fact, the oldest known fossil of a land dwelling animal is a scorpion found in 2013 in South Africa.  Modern scorpions are found on every continent except Antarctica.

Clearly scorpions have mastered the art of surviving on planet Earth and the secret of their success may be their low-key lifestyle. They are nocturnal and hide from daylight under rocks or in burrows, emerging at night to hunt insects. But scorpions are essentially “couch potatoes.” They have a very inactive lifestyle and a low metabolic rate which means they require very little energy or food. Unlike human couch potatoes, scorpions can go a long time without a meal. Some species have been reported to go up to a year between feedings.

Yet scorpions are not slackers in the parenting department. Female scorpions give birth to live young rather than lay eggs. The newborn scorpions are defenseless– their screen-shot-2017-01-14-at-12-23-12-pmexoskeletons do not harden until they are older so their pincers are soft and useless and their stingers are blunt. To keep them out of danger, mother scorpions carry their babies around on their backs until they are old enough to defend themselves.

Scorpions sometimes use their stingers to subdue prey that they catch with their pincers. They will also sting in self-defense, and if they feel the need to defend themselves from your incoming foot– you may be in for some pain. Most scorpion stings are no more painful than a bee sting and ultimately harmless. Only one scorpion in the U.S. has venom powerful enough to cause life-threatening illness in humans. The Arizona bark scorpion, which is found in the Sonoran Desert, has a neurotoxin in its venom that can cause extreme pain and numbness. But fatalities due to its sting are rare.

Scorpion venom may turn out to provide more benefit than harm to humans. The venom contains a number of different chemicals that have potential as drugs. Scientists are currently investigating components of scorpion venom that may be useful in treating brain tumors and malaria. Who knows what other secrets may hide in the scorpion’s stinger?

Though there are plenty of scorpions in the Grand Valley, they keep a low profile and are seldom seen. If you do encounter a scorpion, before you run away shrieking or stomp it to smithereens, take a breath and consider letting it go its merry way. These secretive creatures are less menacing than may they appear.

This article was originally published in the Grand Junction Daily Sentinel in May 2016

The scorpion’s softer side

The Showgirl and the Amazon

Image
The eastern collared lizard (Crotaphytus collaris) ranges in length from 8-14 inches and is found in rocky canyons, pinon-juniper woodlands, and shrublands. (Photo by Brett Walker.)

The warm sunny days of early spring make me feel like a lizard.  I just want to lie on a rock, bask in the sun and thaw out my bones.  The (mostly) warm sunny weather that we have enjoyed the last couple of weeks brought out the lizards in the Grand Valley.  Many of us are familiar with the iconic collared lizard, which graces Colorado National Monument t-shirts.  It is probably one of the most spectacular lizards in North America, and a friend of mine dubbed it “the Vegas showgirl of lizards.”  With their bright yellow heads, speckled blue bodies and striking black neck bands, collared lizards are pretty razzle-dazzle.  Even their behavior is showy- they often perch on prominent sunny rocks as if posing for the paparazzi and have been known to run on their hind legs.

While the collared lizard attracts a lot of attention, the other lizards in our area often go unnoticed, or barely acknowledged as a small dark shape scurrying under a rock as we hike past. At least nine species of lizards live in the Grand Valley, and are most often seen in the red rocks of the Colorado National Monument or McInnis Canyons National Conservation Area.  And while none are quite as eye-catching as the Collared Lizard, they are worth a second look.  The most interesting, to my mind, is the plateau striped whiptail (Aspidoscelis velox).  If the collared lizard is the Vegas showgirl of lizards, the plateau striped whiptail is the Amazon.

Image
The plateau striped whiptail lizard (Aspidocelis velox) is distinguished from other local whiptails by the 6-7 light stripes on its back. The long bluish tail is brighter in juveniles and paler in adults. Adults range in length from 8 to almost 11 inches in length. Although plateau striped whiptails may be less skittish and thus easier to catch than other lizards, when captured, they may play dead or whip their heads around to bite their captor.
(Photo by J.N. Stuart)

In Greek mythology, the Amazons were a race of women warriors who isolated themselves from men, except for an annual visit to a neighboring tribe for the purposes of reproduction.  Any male babies that resulted were killed, abandoned or given to a neighboring tribe- only females were allowed to remain in Amazon territory.  Plateau striped whiptails take this “no boys allowed” policy to an even greater extreme- there are no male plateau striped whiptails at all.  The entire species is female and they don’t even need males to reproduce.  These lizards reproduce asexually, via parthenogenesis, a process in which an egg cell starts dividing and produces an embryo without being fertilized by a sperm.  Because there is no contribution of genetic material from a male, the offspring is genetically identical to the mother and therefore a clone.  Parthenogenesis is actually very common among the different species of whiptail lizards- the Colorado checkered whiptail, which occurs in southeast Colorado is also parthenogenic. Scientists believe that these parthenogenic whiptail species arose when two typical sexual species hybridized.

As bizarre as it may seem, parthenogenesis is not as rare as you might think.  It is actually very common in plants.   All ants, bees and wasps use parthenogenesis to produce male offspring.  It has also been known to occur occasionally in sharks, turkeys and chickens, though usually the embryos that result are usually not viable.

Some of you may remember the excitement (and some anxiety) in 1996 when scientist cloned a sheep.  The animal, which they named Dolly, even made the cover of Time magazine with the headline “Will There Ever Be Another You?”  Many people think clones were creepy and they are a major theme in science fiction novels and movies like “The Stepford Wives,” “Blade Runner” and “Gattaca.”  But for those of us here in the Grand Valley, we needn’t turn to novels or films to find clones- a casual hike up a local canyon might grant us an encounter with a clone in the flesh.  In the case of the Plateau Striped Whiptail, or “Amazon” lizard, reality is stranger than fiction or, in this case, Greek mythology.

This article was originally published, in an edited form, on Wednesday April 24 in the Grand Junction Daily Sentinel.  You can read it in the Sentinel here.  

The Showgirl and the Amazon

When N= 1, Reason= 0

The title of this essay is admittedly a craven attempt to attract the attention of scientists and closet geeks- you know who you are.  For the non-geeks reading this, N is the symbol for sample size or “the number of units in a population to be studied.”  In this case, N= 2 because the “units” in question are my kids and my “study” addresses the intersection of science, the media and parenting.  Or maybe I should say the three-car pile-up.

If you become a parent, you are required to make a lot of choices for your young kids.  Many of these are inconsequential, like will my kid wear overalls or sweatpants, pigtails or a pixie-cut? But many of the important choices have to do with health science issues such as circumcision, immunization, breast milk vs. formula- the list goes on and on.  If you are a geek like me, your first impulse is to research each issue, make your choice and prepare your argument for anyone who questions you (and believe me they will.)  It usually goes something like this “Well, recent studies have shown that yada yada yada…”  Then you pat yourself on the back for being so informed and making a well-reasoned decision.

The trouble begins when you finally graduate or stop working at a university and the powers that be cut off your online library access (the bastards!)  What are you to do without the magic of PubMed or ISI Web of Knowledge?!?   What happens when you can’t get your hands on peer-reviewed scientific journal articles?  You console yourself with the fact that we live in the “Information Age.”  Surely, with Google, a fast internet connection and the myriad forms of mass media available, you should be able to find the information necessary to make well-reasoned, science-based decisions for your children.

Maybe not.  A friend (thanks Andy Jones!) recently shared an article with me entitled “Why Most Biomedical Findings Echoed by Newspapers Turn Out to be False: The Case of Attention Deficit Hyperactivity Disorder.”   (By the way, this article is from the PLoS One, a peer-reviewed, online, open-access publication put out by the Public Library of Science non-profit.  If you are missing your primary literature fix, check it out.)  The gist of the article is that the news media preferentially cover initial findings described in the most prominent scientific journals.  The key word there is initial.  When a scientist gets some really interesting results, she publishes them along with her methods so that other scientists can do their own version of the experiment and try to replicate the interesting result.  If these subsequent studies fail to get the same result, it suggests that the initial study was flawed in some way.  There are myriad ways even a well-done study can be flawed so this replication of results is an essential part of the scientific process and in theory, these subsequent studies are just as important as that initial study.  But in practice, sadly, many of these subsequent studies don’t get published in the most prominent journals because they are not “a big scoop.”  The trouble is that a lot of these subsequent studies end up showing that the initial exciting finding was wrong (or at least overblown.)  In the case of ADHD described in the article above, three of the 10 initial findings they considered were totally refuted and four were attenuated by subsequent studies.  But since these subsequent studies are published in less prominent journals, they are less likely to be covered by the mass media, and those of us living outside the ivory tower are less likely to learn about them.

That brings us to a case that really pushes my buttons- childhood immunizations.  In 1998, Dr. Andrew Wakefield and colleagues published a study in the prominent British medical journal the Lancet, claiming to link the MMR (measles, mumps, rubella) vaccine with autism.  The scientific community immediately pointed out a number of glaring flaws in the study and subsequent studies over the next decade failed to reproduce his results, but it was too late- the popular media, and popular celebrities like Jenny McCarthy, had already latched on. Parents were terrified, vaccination rates dropped and we started having outbreaks of diseases like measles, mumps and whooping cough, which can be deadly.  Yes, subsequent studies that found no link between vaccines and autism were covered by the media- but they received less attention. Because let’s face it, scary headlines get more attention.  The Lancet retracted the article twelve years after its publication and in 2011 a British investigative journalist demonstrated that Wakefield actively falsified data.  Still, to this day vaccination rates have not fully recovered and many scared parents are still misinformed and paranoid about vaccinating their children.  At the 2012 Super Bowl there was an outbreak of measles, primarily among children who had not been vaccinated.  Only 14 individuals were sickened, but if vaccination rates continue to decline, then these types of events will increase in frequency and scale.

Admittedly, the MMR case is an extreme example of the media over-reporting a mis-leading scientific result. Very few scientific studies are retracted and few scientists falsify data.  And it is okay for a scientific study to be (honestly) wrong, that is why the subsequent studies are so important and why we don’t make public health decisions based on the results of one study.  Yes, this is a reductionist summary of the whole to vaccinate or not vaccinate issue.  Not all vaccines are created equal and the arguments for or against them should be taken individually- I don’t really want to get into that whole debate here.  But the MMR-autism controversy is a great example of one initial study and the ensuing media hysteria having a major impact on parents.

So I am sure you can see I am being a bit self-righteous here.  Here I am strutting my formally trained scientist status claiming “I would never be fooled by such hysterical nonsense!”  Well, nonsense.  I am fooled.  I am fooled by the fear that comes with being a parent.  This is the fear that comes with being responsible for defenseless little humans who you love more than anything in the world.  This is the fear that comes with acknowledging all the bad things that can happen to them that you have no control over.  One (of the many) big bad things hiding in my closet is schizophrenia.  A member of our family developed schizophrenia suddenly at age 17 and has not recovered.  Schizophrenia can run in families, so my two children may have up to a 4% chance of developing this disease as opposed to the 1.1% chance that someone with no direct relatives has.

So along comes my March 2012 issue of The Atlantic Magazine featuring an article entitled “How Your Cat Is Making You Crazy” by Kathleen MacAuliffe.  I would have found this article fascinating even if schizophrenia weren’t the boogeyman in my closet, because I am just that kind of weird.  The subject of the article is a parasite called Toxoplasmosis gondii, a protozoan, that usually cycles through two hosts: cats and rodents.  Toxo as I’ll call this beast, starts life as an egg in a cat, that is pooped out, finally moving out of its parent’s cat and setting out to find a cat of its own.  How does it get into a new cat?  Cats, unlike dogs, are pretty fastidious creatures and don’t tend to eat or otherwise mess around with other cat’s poop.  So Toxo gets itself into a less fastidious, but tasty morsel like a mouse instead, hoping to get into a cat if the mouse becomes a kitty dinner.  But mice can find a lot of ways to die and Toxo really wants to get into a cat, so it ups the odds by getting into the mouse’s brain and changing its behavior. The mouse goes from a cautious, life-loving rodent to behaving a bit like a character on that MTV show Jackass.  The mouse’s activity level increases (cats love to chase fast moving objects) and it may become less wary in exposed areas and attracted to the smell of cats.  How does Toxo make the mouse behave like it has a death wish?  It does it by manipulating dopamine, a neurotransmitter in the brain.  Very cool.  (By the way, my summary of the article here does not do it justice.  I recommend clicking on the link and reading it for yourself.)

The trouble is that Toxo does not always find its way into a mouse.  Humans can also become infected when they come in contact with cat poop, eat undercooked meat or unwashed veggies grown in a garden where cats poop.  We have known for a long time that becoming infected with Toxo while you’re pregnant can be very harmful to the baby so pregnant women have been warned off cleaning kitty litter boxes or eating nasty food.  But healthy, non-pregnant adults infected with Toxo weren’t thought to suffer any detrimental effects- until recently.  MacAuliffe’s article focuses on the work of a Czech biologist named Jaroslav Flegr, whose research suggests that Toxo may alter behavior in humans as well.  Flegr’s data suggests a variety of behavioral changes including a reduction in fearfulness and response times.  In most people, these purported behavioral shifts are probably very subtle and unremarkable.  But Flegr suggests that in some unlucky people, Toxo infection serves as the trigger for mental illness, for instance schizophrenia.

The theory among many researchers is that schizophrenia occurs as a result of an interaction between a person’s genes and their environment.  You may have the unlucky genes for schizophrenia, but never develop it because there is no environmental trigger during your life that causes those genes to malfunction.  You may even be able to develop schizophrenia without being genetically predisposed to it, if you have the right combination of environmental triggers. There is a long list of potential environmental triggers including:  childhood stress, prenatal famine, drug abuse and infections with diseases like Toxo.

I am over-simplifying the genetics of schizophrenia and the gene-environment interaction theory here.  I am not an expert on the epidemiology of schizophrenia, but I did briefly try to become one with the help of Google after I read MacAuliffe’s article.  Reading this article set me off on a tear of worrying.  We have a cat, but I wasn’t worried about her.  She is an indoor cat (we love birds) and there is a very low incidence of Toxo infections in indoor cats.  But our neighbors have outdoor cats and there are feral cats in our neighborhood, which sometimes hang out in our yard, where my kids like to play in the dirt and eat things out of the garden, including the dirt itself.  Shit.

I took to Google and researched cat traps and repellants, how to get your kids to wash their hands, etc.  I lay awake at night for hours strategizing about how to keep my home and yard Toxo free.  And then I realized, even if I managed to exclude all cats from my yard and the totally impossible feat of getting my kids (ages 1 and 2) to wash their hands before they touched their faces or food EVERY time, I was still doomed.  My kids would go to friend’s houses and play in their Toxo infested yards.   The only toddlers who wash their hands that diligently probably have OCD, and mine suffer from many behavioral problems, but not that one.

Toxo was something I couldn’t control and I needed to let it go.  At our next check-up I talked to our pediatrician about it, who had never heard about the potential Toxo-schizophrenia link.  She graciously concealed her “oh Lord, another parent with a loony theory” reaction and calmed me down.  As she put it, my only real option to prevent Toxo infection was to never allow my children to play outdoors or in the dirt, and the detrimental effects of that were likely far greater than the risk of schizophrenia, Toxo or no Toxo.  She also reminded me that this potential link between Toxo and schizophrenia is a fairly initial finding and not totally understood. Science and medicine are always making new discoveries.  30 years from now we may find out that feeding kids broccoli causes obsessive compulsive disorder and parents will begin beating themselves up about that.  You just can’t go there.  Or as my father the doctor advised:  If you’re going to worry, worry about them when they start driving.  So I started worrying about that 14 years early and let the Toxo obsession go- mostly.

Obviously I am a worrier.  The intersection of parenting, science and the media may not be a problem for other people.  They may read an article discussing “new research on Sudden Infant Death Syndrome” dispassionately, soberly waiting until evidence from multiple research studies has accumulated and practical recommendations have been made before they take action.  I wish I was one of those people, but I am not and neither are most other parents I know.  Raising kids can be scary and it’s hard to be rational when you are scared. It’s harder still when the information available to you in the media is often designed to scare you, because it will get your attention and sell their publication.  What is the solution?  I am not sure and I’d love to hear your thoughts.  I am sure it includes parents taking a deep breath and trying to keep things in perspective.  I think that the media needs to be more responsible in how they are reporting health science research.  But I also believe that we need to do a better job of science education in our public schools.  We need to teach students (who are future parents) to be better, more critical, consumers of science.  Yes, I think all students need to understand some basic scientific facts.  But perhaps more importantly, they need to understand the scientific process.  By process I mean the both scientific method and how peer review works.  Even when you have scientific training and understand these processes, it can be hard to make a well-reasoned decision.  But if you don’t understand the process of science, it’s almost impossible.

P.S.  For another interesting perspective on this topic check out this post on the blog Science of Mom.

When N= 1, Reason= 0