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.

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!

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.

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 oppositus.  A deeper dive found a picture of the critter in action below. 

Marina Martelli

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.

Rusty Spider Wasp

Building her nest - BC

Ben Caruthers comes through again with a great set of pictures.  He shot this red wasp and identified it as a rusty spider wasp (RSP), a lot easier to pronounce than its scientific name Tachypompilus ferrugineus.  This is a large and impressive wasp that dives into its work head first.

 

Click to enlarge - MDC

Spider wasps belong to the family Pompilidae.  These wasps visit flowers for nectar but their fame comes from killing spiders to feed the family.  The female stings her spider prey into paralysis and then drags the spider backwards to her nest, gripping the incapacitated spider with her mandibles.  The trip can be long and laborious as the spider is frequently much larger than the wasp.  Maybe that is why they call it going into labor?

With a wolf spider prey - Ted Kropiewnicki CC

Once the nest is prepared to her satisfaction, she grabs the spider and rolls it over so it is on top of her while she deposits a single egg before covering it with soil.  I frequently wonder how we know details like these but in this case it was observations by R.W. Strandtman described in this more detailed source.

The RSP specializes in collecting wolf spiders (Lycosidae).  Other species of spider wasps also tend to specialize in their spider prey, some with free living hunting species and others using web spiders.  The young wasp will get all its nutrition from this spider while all adults feed on nectar.

After this considerable effort to deliver and feed a single young, I wonder if she doesn't tell the next male that finds her, "Not tonight, I have a headache!"

Giant Walkingstick

I found this stick insect in the bed of my truck after emptying a load of cut branches.  This is a giant walkingstick,  Megaphasma denticrus, quite distinctive in coloration.  This is the longest insect in North America, reaching up to seven inches long.

It had a rough day and was missing one leg but that didn't keep it from climbing onto my hand and start heading upward, the only direction most stick insects want to go.  During the day they cling to the tree, sometimes swaying a little like a small branch.  Their defense is to drop to the ground and they are light enough to survive the fall.  Then they immediately start to climb up for food and shelter.  M. dentricrus adult's favorite food is oak and grapevine leaves.

This specimen is a male, defined by a large, single spine on the underside of its mid and hind femora, the first leg segment like our femur.  Another distinctive male feature is the clasper at the end of its body.

Copulation - Marvin Smith CC

Males tend to be smaller and far fewer than females.  The copulation consists of the male using his clasper to hang on to the female's genitalia, fertilizing the eggs as they come out and immediately drop to down to the forest floor.  The male may hang on for several days, eating during this time. 

The female may produce 150 eggs with three eggs per hour.  Her ovipositor has a small flipper which propels them randomly, ensuring that they are scattered and less likely to compete for vegetation.  (See ADW)

 

Clasping copulation - Marvin Smith cc

The young offspring feed on grass and leaves, particularly oaks and grapevine.  They will go through four to five molts before achieving sexual maturity.  This species is known to regenerate a missing limb but in this case I wasn't able to raise it long enough to make it to the WOLF School alive.  I think it died of a lonely heart, never having reached its biological imperative.

Ben Caruthers sent this incredible macro of its eye.  Now check this Bugguide link for more photographs.

 

The Ant that Ain't - Cow Killer

Our unpaid staff photographer Ben Caruthers sent me a set of photographs of a velvet ant that are too good to pass up. I updated this blog from 2013, guesssing that you won't remember it.

Female Velvet Ant

Some years ago I was out with some young naturalists.  All kids are naturalists if given a little freedom and encouragement.  They found this critter running rapidly through the cropped grass and weeds by our swimming hole.  The consensus among my young naturalists was "Wow, look at that ant!" and they were partially correct.  It is a velvet ant, an insect that "ain't really an ant."  I chased this swift creature for several minutes before catching in it a bug box.  Due to its formidable appearance,  I wasn't tempted to pick it up, a wise decision.

Male Velvet Ant - Ben Caruthers

This is a wasp called an Eastern velvet ant, Dasymutilla occidentalis. Although he looks wicked, he lacks a stinger as do all male wasps.  As a rule of thumb, I assume that all wasps are female until proven otherwise.  In this case however, the females lack wings and don't even look wasp like.

Male side view - BC

Velvet ants are characterized by their dense hair in vivid shades of red, orange or yellow.  The winged males have a different coloration than the wingless females.  Bright colors in insects are frequently warnings of toxicity or the ability to hurt predators like us.  Other harmless insects may also have these bright colors called aposematic that falsely warn of their toxicity.  In this case, the females are the real thing.

"I am not smiling!" - BC

Their other name is "cow-killer" which probably gives you a hint of their defense.  The name derives from the female's stinger.  She has a sting that is rated as a three on a one through four Schmidt sting pain index scale.  Justin Schmidt prompted insects to sting him and then graded the severity of the pain in terms generally reserved for a wine connoisseur.  These ranged from "light, ephemeral, almost fruity" to ""hot and smoky, almost irreverent. Imagine W. C. Fields extinguishing a cigar on your tongue."

Adults feed on nectar and water.  The male flies around looking for females on the ground.  They are parasitoids, rearing their young in nests of other species, eventually killing them.  When they emerge, the males fly off while the females crawl away as a warm and fuzzy "ant" - well maybe not so warm.

"Male mutillids fly in search of females; after mating, the female enters a host insects nest, typically a ground nesting bee or wasp burrow, and deposits one egg near each larva or pupa.  The mutillid larvae then develop as idiobiont ectoparasitoids, eventually killing their immobile larva/pupal hosts within a week or two."  Wikipedia

Surprisingly, the female's toxin isn't all that strong.  The severe pain is due to the extraordinarily long stinger!  Even without a stinger, the wasps have other defenses against predators.  In addition to its coloration and a thickened exoskeleton, when bothered they emit a stinky chemical secretion.  Also both males and females run fast which Ben mentioned makes them hard to photograph, let alone catch.  When threatened, they make warning sounds and clicks by rubbing their body parts together, a trait called stridulation.

Best to remember that their attitude is "just leave me alone!"

 "You wanna pick me up?"  Wayne Boo at  USGS