Wednesday, November 16, 2022

Scorpion

 

This is a vicarious two-part digital field trip to Rocky Barrens Conservation Area with Kevin Firth and Chris Barnhart.  This find led me and the WOLFs on a deep dive.

They photographed this cute little creature which has the typical features of a scorpion, immediately recognizable to most of us who have never seen one in the wild.  It has a long tail with a stinger curved over the body and large pincers in front like a beached crayfish.  

This is a striped bark scorpion, Centruroides vittatus, the most common and widely distributed scorpion species in the USMDC says "This is the only species of scorpion in Missouri. It occurs in glades and other dry, warm, rocky areas, and sometimes in buildings and shelters and under piles of wood, brush, or garbage."

Scorpions are arachnids like the ever popular spiders, ticks and mites.They all have an exoskeleton and 8 legs unlike the insects' 6 legs.  They also have a pair of chelicerae for feeding and defense and a pair of multipurpose pedipalps.

They consume soft-bodied prey such as spiders, cockroaches, ants, crickets, beetles, and butterflies. Grabbing the prey with their pincers, they sometimes use their stinger to subdue it. 

The tail and stinger was familiar to me from childhood where every cowboy worth his saddle would encounter them in the movie westerns.  Although they had a deadly reputation on film only 25 of the 2,500 known species have venom capable of killing a human.  Usually a sting is mild although allergic reactions can cause more severe problems.  Mexico on the other hand is one of the most affected countries, with the highest biodiversity of scorpions in the world, some 200,000 envenomations per year and at least 300 deaths.*

I enjoy Fun Facts just like my 5th grade WOLF School colleagues.  Here are a few:

  • Their hard exoskeleton is fluorescent when viewed under ultraviolet light.  Most species are nocturnal hunters and can be found with a UV flashlight at night.
  • Unlike their other arachnid cousins, they are viviparous, meaning they give live birth.  The female hoists the young onto her back where they remain until their first molt.
  • Scorpions have two eyes on the top of the cephalothorax (fused head and thorax), and usually two to five pairs of eyes along the front corners of the cephalothorax. While unable to form sharp images, their central eyes are amongst the most light sensitive in the animal kingdom, especially in dim light, and makes it possible for nocturnal species to use starlight to navigate at night! * 

*Wikipedia

Thanks to Kevin and Chris for the glade trip.  We hope to tag along again sometime.

Friday, November 11, 2022

Tarantula!

Chris Barnhart was hiking Rocky Barrens Conservation Area with Kevin Firth when he got these pictures of a tarantula.  Kevin goes there regularly to check on burrows that hold them, knowing which rocks to lift up where they are hiding.  

This is the Texas brown tarantula (TBT) Aphonopelma hentzi.  There are over 900 tarantula species world wide.  The MDC website says it is the largest spider in Missouri and the only species of tarantula found in Missouri versus 50 species in the US, mostly in the southwest.  The female's body length averages 2" so you can imagine the length of the legs above.

Tarantula in hole to left, note silk lining

Our TBT spends its days in its silk lined hole, predominately on rocky barren glades.  They use holes created by rodents and reptiles and provide their own lining.  Emerging at night to hunt, they predominately feed on crickets which they paralyze with venom, then chew while mixing their digestive juices with it before slurping up the liquid dinner.

After mating, the male pushes away vigorously, at times even causing her to fall on her back.  He is avoiding the female's attack as he is no longer useful except as dinner where he would be nourishing his future offspring.  He doesn't live long after that anyway so she likely considers him disposable.

She will lay out a sheet of silk and deposit her eggs with a nutritious fluid.  She then guards the egg sac and even moves it to maintain the best temperature.  Some tarantula species carry their egg sac for three months before the eggs hatch into the post embryo stage.  They remain in that sac that Cowels describes in Amazing Arachnids as "eggs with legs."  Once they absorb the rest of the egg juice they proceed to molt many times as they grow to adulthood.

Like all other arthropods, molting consists of growing a new larger cuticle under the old, then splitting out of the old outer coat with enzymes that break it down.  Molting also renews the inner surfaces, such as the mouth, as well as external and for a period of time they can't eat during each molt.  They are also softer and more vulnerable during this time.  The good news is that with molting they can regrow a damaged or missing leg. 

Fishing for a tarantula with grass

Kevin was able to draw this tarantula out with a strand of grass.  It grabbed on and he could slowly pull it out.  This requires some patience as their bodies are somewhat fragile.  They are covered with urticating barbed hairs that are stinging or irritating to the skin.  Some species can shake these loose when irritated and inhaling them can be dangerous so don't make a habit of sniffing a tarantula.

They are slow moving and near-sighted.  They sense the world largely through vibrations felt in another type of hair on their legs.  To escape they can move more rapidly but not with accuracy.   Many species are able to make sounds by rubbing their hairs on their legs together, called stridulation similar to crickets and some other insects.

*Fun fact.  Female TBT have been known to live 30 years.  Chris raised one as a pet for 10 years early in his marriage to the ever-patient Deb. 

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This is a vicarious two-part digital field trip to Rocky Barrens Conservation Area with Kevin Firth and Chris Barnhart.  Next up, the Striped Bark Scorpion Centruroides vittatus.

Tuesday, November 1, 2022

Red Velvet Mites

Our WOLF School field trip last week included hiking down the old Mail Trace Road looking for little things in the woods.  Almost every student found one or more of these small things crawling slowly in the leaf litter, red velvet mites ( RVM). They are also called "rain bugs" because they come out after a rain like we had earlier. 

Mites are arachnids as are spiders, harvestmen, scorpions and the ever popular ticks.  Like ticks they have six legs in the first instar, then graduate to eight legs from then on into adulthood.  RVMs are members of the Trombididiidae family of mites which gives us several thousand species to choose from.  

You can see "velvet" close up.

Their lifecycle is complicated, beginning as eggs and then several inactive pre-larval stages.  The final larvae are parasites on insects and spiders (but not us mammals!)  The adults feed on the insects or their eggs, then mate and produce eggs for the next generation.

RVM are not chiggers and it is hard to find good reputable photographs of real chigger mites. There are several species with the blood-sucking habit, the most common being Trombicula alfreddugesi.  Their larva sticks its proboscis into our skin and injects digestive juice which hardens into a tube called a stylosome, the source of the itching inflammation as described here by Missouri University.

Wikipedia
Chigger mites on the other hand are tiny, requiring a magnifier to see them.  I doubt if anyone reading this has ever seen the mite.  Only the 6 legged larval stage is parasitic, feeding on reptiles and birds. The MDC Field Guide tries to reassure us that "mammals (including people) are secondary, almost accidental hosts."

"Their presence is best known, instead, by the intensely itchy welts they leave behind, usually where your skin is thin and tender (ankles, backs of knees, about the crotch, under the beltline, and in the armpits) and where tight clothing proves an obstacle to them (as where a belt or elastic band limits their wanderings).  Chigger bites sometimes have a tiny red dot at the center, which is the remains of a scablike tube your body formed in response to the chigger's irritating saliva."

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The Bug Lady has in depth information on RVMs and their interesting mating habits at this link.

Wednesday, October 26, 2022

A Fungus Among Us

I had these photographs of a moth with a bad hair day sent to me several years ago and just got around to identifying them.  I have lost track of who sent them but the story was too good to pass.

I had identified it as a fungus, Akanthomyces tuberculatus species complex on an unfortunate moth. My understanding was that the fungus parasitizes the host, eventually killing it, then acts as a saprobe, feeding on the corpse. When it is finished, it produces projections which are covered with asexual spores to find another victim.  I sent it off to our staff mycologist.  He takes the story over from here:

Mark Bower:

You are correct about what has happened to that poor moth. It came into contact with an Akanthomyces (tuberculatus or aculeateus, don’t know which one) spore. the spore stuck to the moth’s body, germinated, penetrated the body cavity, then devoured it from the inside. After the fungus was finished with its meal, it sent up spore-bearing structures as seen in your photo.

Below are a few Bull Creek examples of entomopathogenic fungi (a fungus that kills or disables insects).


Pupa infested with Cordyceps militaris

There are over 1,000 known species of entomopathogenic fungi which parasitize or infect insects. Most of these fungi are capable of infecting multiple insect species, but some are species specific. Your example represents a pretty straight forward lethal infection, but it isn’t always this simple. 

Bavaria bassiana which has killed a wasp

O. unilateralis-Wikipedia
Numerous fungal species not only parasitize and kill their hosts; they are actually capable of altering their behavior prior to their inevitable deaths. The most well-known example is Ophiocordyceps unilateralis, a tropical fungus which infects carpenter ants. After entering the ant’s body it attaches to it’s muscles and basically takes over its motor function. It then produces chemicals which somehow affect the ant’s brain. The combination of the altered brain function and the fungus’ control of the muscles cause the ant to climb a plant and permanently clamp its jaws on the vein of a leaf. Remarkably, at noon, the infected ants climb to 25 cm from the ground, and do so over the top of one of the ant colony’s trails or nest. The fungus then sprouts from the ant’s head and rains spores down on the unfortunate ants below. 

The previous story is bizarre, but this type of fungal-insect interaction is actually fairly common. Male periodic locusts can be infected by a fungus which devour it from the inside, all the while producing chemicals which cause the males to be hypersexual, so they buzz around trying to mate with every locust (male or female) that moves. This behavior enhances spore dispersal. Also, some species of flies can be infected, causing them to land on the top of a plant (such as a blade of grass), raise their butts upwards and die. This position enhances spore dispersal.

Torrubiella arachnophila which has devoured a spider

Editor's note:

Thanks to Mark Bower, I will now be worrying about a zombie fungus every time I climb to any heights.

Wednesday, October 5, 2022

Slime Molds

Today's blog is by the our award winning photographer of fungi, Dr. Mark Bower.  I asked him to tell us a little about slime molds, with added comments in italics by your editor.

For lack of a better idea, Slime Molds have been placed in the Kingdom Protista along with amoebas, algae, kelp and other oddballs. They spend most of their lives as single-cell amoeba-like individuals, oozing around in soil, feeding on bacteria and fungal spores. Yummy, delicious.


They are extremely common- one pinch of forest soil may contain around 50,000 individuals. They have been found in a wide variety of ecosystems, from the arctic to the deserts of Namibia. While they are virtually indistinguishable from amoebas, there is one important difference: unlike amoebas, Slime Molds, under certain circumstances, join together to form a completely new multicellular organism. In the case of the myxomycetes this new organism consists of a mass of slimy goo called the plasmodium.  No more barefoot walks in the woods for me.

Slime mold imitating a millipede

The slimy plasmodium creeps around, feeding and enjoying itself until it decides to stop and morph into its fruiting bodies, which produce its spores. If you think myxomycetes are weird, let me tell you about dictyostelids some day!  Be still my foolish heart!

Plasmodium of Ceratiomyxa fruticulosa

Here is the decidedly slimy plasmodium of Ceratiomyxa fruticulosa - the white stringy things are the developing fruiting bodies.  Grapes of wrath?

Mature fruiting bodies

While all myxomycetes have a pretty similar plasmodial phase, there is wide variation in the shape and character of the fruiting bodies. Here are just a few examples:  Who knew the words "slime" and "mold" could describe this kind of natural beauty?


Pretzel past its best used by date



Dead finger applauding Mark's pictures

Here is an entertaining three minute video that further explains slime molds.  Many more of Mark's slime mold photos are at this Flickr link.  Here is more from your National Park Service.

Thanks Mark, now off to dinner!

Friday, September 30, 2022

Owl Pellets

 

I recently was gifted owl pellets by Ben Caruthers. The dried undigested regurgitated remnants of an owl meal is an exciting exploration for a 5th grade WOLF student. I stored them in paper egg cartons inside a ziplock bag in the dining room. I have a very tolerant wife.

Exuviae of emerged moths - notice the wing features below

When I opened them a month later I could see exuviae, empty pupa cases with remnants where there had been wings developing. Among the collection of digested rodent bones, some of the debris was moving. After filming it, (a historic term for video), I extracted a wiggling piece of debris and captured a case-bearing larva attempting to escape as seen in this video.

 
The larva lives this stage of its life in a tunnel it glues together from debris.  The owl pellets in the egg carton had a least a hundred of these little guys.  Now the question was what were they?  
 
6 mm moth in owl pellets

A week later I had an answer.  I found several of these 6 mm long moths in the bag.  a quick Google search of "case-bearing moths" returned lots of links pointing to clothes/carpet moths in the Tineidae family.  The majority of these feed on fungi, lichens, and detritus, which fits with the material in these pellet remnants.

This is most likely the case bearing clothing moth, Tinea pellionella.  They are distributed world wide and are frequently associated with human populations.  There are a few other similar species in the family that can only be identified by examining their genitalia so we won't go into that.   

"T. pellionella larva eats mainly fibrous keratin, such as hairs and feathers. It can become a pest when it feeds on carpets, furs, upholstery, and woolen fabrics. It also consumes detritus, cobwebs, and bird nests."  -Wikipedia

The larva lives inside a snug case it constructs from debris such as fibers and hairs.  It extends its body to crawl around, hauling its home for protection.  Incredibly, it can turn around in the case to protrude its head and legs at either end and drag the case in either direction.  Finally they will form a pupa and eventually crawl out and expand their wings.

So back to the other question, what are owl pellets and why would a grown man collect them?  Owls often swallow mice, voles, small birds, and other prey whole.  After its gizzard has sorted out the indigestible parts such as fur, feathers, teeth and bones, the owl regurgitates them in a oval owl pellet.  This frequently occurs in a roost where they collect on the ground underneath.  Taking these to the 5th grade WOLF School, we students young and old, will examine them to try to determine what the owl had been eating. 

 

There are lots of resources available to students of all ages.  This brings out your inner 5th grader without having to get on a bus every morning.

Tuesday, September 27, 2022

Summer Egg Hunt #

Tonya Smith sent me on a non-Easter egg hunt with these picture of a string of barrel shaped eggs laid on a mulberry sapling leaf.  A search for insect egg photographs brought out a likely suspect, a leaf-footed bug, Leptoglossus oppositusA deeper dive found a picture of the critter in action below. 

The name leaf-footed bug comes from the shape of the tibia of many of the Coreidae family.  There are 88 species known in North America.   L. oppositus is extremely common across the eastern US and I find lots of them in the fields every year along Bull Creek.  

 L. oppositus is distinguished by the deeper scallops in the leaf-like feature of the hind tibia and the addition of three white spots across the hemelytra, the name of forewings in true bugs.

Proving the identification of the eggs down to species is hard but I would argue that the circumstantial evidence is strong.  Red mulberry is one of the host plants of the species as listed in BioOne.

Eggs closeup - Tonya Smith
Laying eggs - William Dedo

 


 



 
The eggs that Tonya photographed with their barrel shape and bulls-eye circle are fairly distinctive as seen at several sources.   Now enough of this hunt, it is time to go back to work.  No, not really - this isn't really work.