Saturday, November 9, 2019

Dermestids in a Skull

Dermestid beetle larvae
So, reaching for a new height in the ridiculous pursuit of weird tiny insect life, I present you with dermestid beetle larvae found in a deer skull.  We have taken this skull to WOLF the last 3 years while it spent the rest of the time in a bag upstairs at the creek house.  When Barb took it out at WOLF some powder fell out of the base of the skull and a student noticed that something tiny was moving.  Magnification with a digital microscope showed cute fuzzy larvae.

Chris Barnhart identified the photograph as Dermestid beetle larvae.  There are over 500 species of beetles in the Dermestidae family with a variety of lifestyles.  Most of the larvae are scavengers, living on dry plant and animal matter, sometimes with very specific tastes.  Dermestid larvae are profoundly covered with varying lengths of hairs (setae) that gave them a distinctive appearance. The larvae are generally dark brown to black and go through complete metamorphosis.  Adults are less commonly found and feed on flowers and shrubs.

Ventral view of exuvia within their dried frass
Some dermestids are famous for their forensic connections, living on dead animals and giving clues of the time of death.  They are available on line to use in cleaning skulls and bones of animals in laboratories for the study of anatomy.  Our larvae had been surviving in a deer skull for several years.  Fortunately they like to eat dry dead stuff.

Home on the frass
Above you can see the results of life in a deer skull, lots of larvae moving around in their world of frass and molted skins (exuvia).  This prompted me to make  this video for a closer look.  For more information on the value and risks of using Dermestids to clean bones, watch this educational PBS video showing the beetles at work.
More species are discussed at

Wednesday, November 6, 2019

Yellowjacket Nest

Syrphid fly, Milesia virginiensis on my arm

I was chasing a tiny skink through the leaf litter six feet from our front door when I saw several yellow flying insects.  We have Syrphid or flower flies on our deck regularly, scaring visitors as they look like yellowjacket wasps but I wasn't fooled..... yet.  I got out my pocket camera to get some closeup videos, a big mistake.  Just then I saw five swarming around in the grass and then more hovering around a finger sized hole.  I thought "Do Syrphid flies nest communally?"  just 2 seconds before the first of several stings - "Yellowjackets!"

I ran backward swatting them off and the attack stopped as the swelling started under three stings.  We love nature but occasionally nature gets too close and our house qualifies as unnatural.  After applying ice to the stings with unimpressive results, I got a can of "kills on contact" wasp spray and soaked the hole from a distance several times.  I returned 20 minutes later with my telephoto camera. (Note to self - video wasp nest = telephoto).

In spite of the insecticide, the hole was busy with wasps coming and going for the next 8 hours.  Many of the outward bound were carrying something in their mouths.  They were moving too fast to see what they were carrying.  It looked like they were panicked and evacuating the hole.  So much for the "kills on contact" on the spray can.  Apparently Ozark yellowjackets can't read.

YJ with a mouth full of rock - REK
After converting the video to 8x slower playback* it became obvious that they were not planning on leaving.  They were actually carrying out small pebbles, enlarging their quarters, carrying on like nothing had happened.  I had a lot to learn about yellowjackets.  This intriguing Youtube video by Bret Davis, aka Hornet King** was a great introduction to the subterranean world of yellowjackets.

Outer bottom layer with side holes - B. Davis
YJ usually build their paper nests underground, starting in a small hole created by a mouse or something similar.  As they create the cells for the offspring of their queen, they work around the outside edges of the paper nest, excavating rocks and soil to enlarge the nest.  As the colony grows they create several side holes (starting at 20:30), slowly digging a larger hole which will be filled with new layers of the nest.

Seven layer yellowjacket nest -  Hornet King, B. Davis
So how big do they get?  This one was removed from a 14" X 9" hole fully excavated by the wasps themselves!  I don't know about records but Bret's weighed an estimated 10 pounds.  (Taking a nest with scattered yellowjackets on it to the bathroom scale in the name of science probably isn't a good idea.)  His nest was seven layers deep.

Weaving a cap -Click to enlarge  (HK)
His video is 27 minutes long but well worth the time.  Unlike many videos focusing on the excitement and danger of stings, Hornet King vividly shows the process of nest building.  Here for instance he shows the larvae beginning to weave a silk cap to to paper homes where they will pupate.

As I nursed the swelling over the next 5 days, I identified my new neighbors as eastern yellowjackets, Vespula maculifrons.  Baldfaced hornets (Dolichovespula Maculata) are yellowjackets with a pale makeup.  Both are colonial nesters but hornets nest above ground while YJ are usually below ground or in enclosed spaces like the soffit of a house.  We have that problem with our red Polistes wasps, but at least they aren't quite as irritable.

Additional thoughts from Hornet King:
There are many subspecies of wasps in the Dolichovespula grouping. Another of the Aerial nest builders is the Dolichovespula Arenaria, which look very similar to the subterranean YJ (Southern Yellow Jacket - Vespula Squamosa) species. This subject is always a area of confusion for my many of my viewers as they think "Yellow Jacket" is a term only given to yellow and black wasps. However, there is more to the classification than just its yellow body (Bald faced hornet being a prime example)

 Promachus hinei with YJ

I did have some slight consolation as I sat on the porch swing balancing ice on my stings.  A loud and coarse buzz announced the arrival of a robber fly, Promachus hinei, on the swing chain.  It was holding a yellowjacket in its jaws and seemed to be showing off its catch.  I photographed it and watched it fly away.  It pierces the body of its victim and sucks out the insides, appropriate justice in this case.

Slow motion video of yellowjackets rock excavation
**  The Hornet King Youtube channel has many more detailed explanations of the nests of other colonial nest builder wasp species.
Yellowjackets on Bugguide.
Yellowjackets and Hornets on University of

Monday, November 4, 2019

Frost Flowers Revisited

Early frost Flowers - Mark Bower
We are at the beginning of frost flower season although few botanists will ever see them.  The "blooms" extrude around the lower stems of Verbesina virginica on nights where the temperature drops well below freezing and they fade after a few minutes of direct sun or as the temperature reaches the mid thirties. 

The delicate sheets of ice split the stem's epidermis lengthwise, thin enough that you can see your finger print through them.  Early in the season they may extend 12 to 24 inches up from the base but as the winter rolls on they become shorter and eventually somewhat thicker.  A hard freeze for several days which freezes the roots will end the season prematurely.  Our personal record was 40 nightime blooms over a winter.

The mechanism of FF is the ability of water to "supercool," that is to drop below 32 degrees without crystallizing.  This is what allows clouds to hold liquid water in the colder atmosphere.  When supercooled water is shaken or encounters a foreign particle it freezes rapidly, accounting for the icing on aircraft wings when they fly through cumulus clouds.  This also accounts for the large accumulation of ice on trees and powerlines in ice storms that are so memorable to those of us in the Ozarks.

This is what happens when the supercooled water extrudes from a V. virginica  and contacts the outer stem's epidermis.  You can see the dramatic ice crystalization of supercooled water in this demonstration on Youtube.

Mark Bower
FF asks a question - Mark Bower
As frost flower season progresses the "blossoms" are lower to the ground and take on many extraordinary shapes.  Stems may be damaged or horizontal but the ice marches on.  Cups, curls and spirals are created, demonstrating nature's varied designs and sometimes a sense of humor.

White crownbeard - MDC
This is the time of year to be watching for frost flowers along the weedy edges of fields and roadsides.  These most commonly occur along the stems of Verbesina virginica, a plant with small white flowers on 3-5 foot stems that are winged along the edges.  It has a confusing list of common names including frostweed, white crownbeard, iceplant, iceweed, and wing stem.
Frost flowers on dittany
FF also can be found around the base of Cunila origanoides, whose common names include dittany, wild oregano, stone mint, and frost mint, and Pluchea camphorate. also known as stinkweed.  These are smaller plants that are common in Missouri but less likely to cover a field edges.*

You can see some of the exquisite shapes that Mark Bower photographed before this last Friday's WOLF School field trip in this Flickr album.
* Reports of FF on yellow crownbeard (Verbesina alternafolia) are probably due to confusion with Verbesina virginica as they frequently grow together and are hard to separate in winter time when the flowers are off.  We have been monitoring tagged yellow crownbeard for years and have never seen FF on them.

Thursday, October 31, 2019

Leopard Slug

This story is from Alee Huerta who has returned to the MN fold after an absence while pursuing her education.

This past weekend we had a Leopard Slug crawl across our porch. My 1st thought was to grab the salt... and I did.  But as my 7 year old buddy and I plopped down with the salt, my inner Naturalist was like.... "hold up."  I'm glad I took the time for education because I found out that these slugs don't actually destroy living plants, a common misconception.  Leopard Slugs (Limax maximus) eat fungi, rotting plants and even other slugs. They need to keep their bodies damp in order to breathe, so are usually found in dark, damp places, particularly among rotting logs.

Mating Slugs - Wikipedia
All slugs are hermaphrodites, meaning that each slug has both male and female sexual organs. They still need to mate with another individual though and LS have quite a spectacular way of doing this. The two slugs climb a tree or other structure, then hang from a branch on a thick strand of mucus, intertwined with one another.   Their sex organs protrude from their heads and intertwine to exchange sperm.  These are bluish colored shown in the photograph.  Editor's note:  This is a family blog but we will recommend this graphic BBC video as it is narrated by the very proper Richard Attenborough.

After mating, each slug lays clutches of transparent, round eggs in damp places.  As slug babies, they are a primary food source for lightning bugs! I love lightning bugs, so the way I see it, to love any one certain thing you need to respect everything that one certain thing needs.  They reach sexual maturity in 2 years and can live for 3 years.

Limax maximus, literally biggest slug, originally were native to Europe and Mediterranean countries of Africa and were first found in Philadelphia in 1867.  In spite of their top speed of 6" per minute they really get around and are now found around the globe! They are almost always found near human habitation — usually in lawns, gardens, cellars, outbuildings or in other damp areas.

LS is generally a nocturnal slug that feeds mostly on rotting plant matter and fungi as well as other slugs. In Texas and Oregon it can sometimes be a pest of gardens, greenhouses, cellars, and mushroom beds.  On the other hand, by eating dead and rotting plants, as well as fungi, Leopard Slugs recycle nutrients and fertilize the soil.
Our LS like many other slug species have a small disc of shell inside their body. Slugs evolved from snails and this disc is a remnant of what used to be the snail’s shell.  They can come in a wide range of shades although these leopards never change their spots.

Finally, research by Christie Sahley and colleagues have demonstrated associative learning in LS by aversion therapy.  Carrot and potato juice normally attracts them.  After they have been exposed to them flavored with an additional bitter dose of quinine sulfate, these attractants subsequently lose their gustatory charm.  Yes, it appears you can teach old slugs new tricks.
Dr. Chris Barnhart and MDC have just published Land Snails and Slugs of Missouri, available in many different formats at this Archive link.  You can download it as a PDF or Kindle document.

Sunday, October 13, 2019

Twig Girdlers

Twig girdler, Oncideres cingulata - Dave Rintoul
This is the time of year our forest floor becomes littered with small tree branches with a distinctive break at the end.  They look like they have gone through a blunt pencil sharpener, ending in a jagged tip.  This is the work of twig girdler beetles, Oncideres cingulata.  These are long-horned beetles of the Cerambycidae family.  

In the summer after mating, the female straddles a small branch and chews a V-shaped groove in the outer portion around the twig, leaving the center portion intact.  Her feet grip the tender bark, leaving a series of horizontal grooves in the distal branch.

Hole for egg - Chris Barnhart (CB)
Next she chews a small hole in the bark of the outer half of the branch and deposits an egg under the bark.  
The eggs are long and narrow, fitting into a tiny hole usually at the site of a side branch.
Egg in its chamber - CB  Click to enlarge

The number of eggs per twig normally ranges from 3 to 8 but may range up to 40. Adults live 6 to 10 weeks. 

Each female deposits 50 to 200 eggs which hatch in about 3 weeks.

Larva writhing around in its frass chamber - (CB)
This will be her offspring's home until next summer, slowly enlarging its chamber while living in its woody poop (frass for insect connoisseurs).  Her larvae require dead wood to develop and the cut effectively cuts off the twig's circulation.  They cannot fully develop in green twigs with high moisture content. 

The legless grub will live in the twig all winter whether it falls to the ground or occasionally dangles from the tree. The chamber hollows to provide a winter home as the grub rests.  It starts feeding again in the spring and grows up to an inch long, living in a world of its frass which provides some insulation.  Eventually it chews an exit hole for the future, then pupates in the frass before emerging as an adult beetle in late summer.

You can see some of the action in Dr. Chris Barnhart's video here.  Meanwhile a couple of beautiful final portraits from Chris of the emerged adult, Oncideres cingulata.  
Note: 2013 blog updated with video.

Sunday, September 29, 2019

Wolf Spider Hole

A front hall made from dried grass and silk - REK
Another view
On our MN training field trip to Henning CA we came across several of these mystery features in the barren ground between grass clumps.  They were approximately 6-8mm in diameter (1/4 inch) and extended 8mm above the ground.  They were constructed from bits of dried grass.  I sent it to Chris Barnhart while we were in the field and he suggested a wolf spider hole.

Burrowing wolf spiders are in the genera Geolycosa (geo=earth, lycosa=underground).  Most of these are found in Florida but one species, appropriately enough named Geolycosa missouriensis, is found all the way into Canada.  Based on circumstantial evidence alone, I am calling this its home until someone comes up with a better suggestion.

Kurt Schaefer
Geolycosa missouriensis is a common species of spider within the wolf spider family, Lycosidae.  These are all ground dwellers, efficient predators with good eyesight that hunt with speed and strength to capture prey items.  They don't build webs and reserve their silk for lining their tunnels and collecting debris to form a little raised opening.

This Bluejay Barrens blog has good photographs of the spider in its burrow.  Looking closely you can see the diagnostic eye arrangement of a Lycosidae. 

As usual, insect guru Bug Eric has a lot more detailed information.  Finally, here is a video of an unidentified wolf spider goaded out of its home.

Friday, September 20, 2019

Yellow Garden Spider Revisited

I took one look at you ....and my heart stood still--------Rogers & Hart
On a field trip with the future teachers of Discover Nature Schools we ran into this beauty.  The distinctive zigzag pattern seen vertically through the web is called a stabilimentum. It is common among the Argiope sp. (Ar-gee-O-pee) spiders but is produced by over 80 spider species.  A. aurantia makes an especially thick stabilimentum. It is called a "writing spider" from an old old folk tale that says if you see your name written on its web you are about to die.  So much for the kind and empathetic writing of Charlotte's WebNo students were lost on this trip.

This is a female Argiope aurantia, the yellow garden spider.  The females are three times larger than the males with a body length of 19-28 mm.  The Araneidae family members all have eight eyes in a distinctive arrangement but with black eyes on a black face they are hard to photograph.  This is a very active spider that crawls all over our hands.  I was finally able to get head shots by gently holding it between soft foam rubber pads.  Her pedipalps are long and narrow compared to a male's which are specialized for the job of transferring sperm.

Male and female - Jay Barnes
The beautiful circular web A. aurantia builds is temporary, as they eat all but the long foundation webbing every night, spinning a new web for the next day. Some sources suggest they may do this to add tiny particles to the webbing which look like food to small insects, drawing them to the web.

The zigzag stabilimentum is especially interesting. It is made of a slightly different webbing which reflects UV light, possibly attracting insects to it. It is important to recall that other species frequently see different light waves. Other biologists believe the stabilimentum is made to strengthen the web, confuse predators, or to warn birds not to fly into the web.

A stabilimentum didn't save this hummingbird that flew into a web in front of one of our cardinal flowers, Lobelia cardinalis.  The closely related Argiope trifasciata spider went into its reflex action of wrapping up its prey (or bycatch in this case).  It is possible however that the hummingbird wasn't an entirely innocent victim.
"Hummingbirds use spider webs as a source of spider's silk in nest construction, being necessary to bind the nest to the tree branch or other substrate and to hold the nest together. Even so, the hummingbird must be careful when removing the pieces of webbing, for it may become entangled and be trapped there. Spider's silk has a tensile strength comparable to steel on a weight basis. In one report, a ruby-throated hummingbird was caught in an active web, and quickly wrapped and encased by the spider, much as an insect might be."
Spider web construction varies with the species and many spiders don't even bother to make one.  The initial strand in web construction of Argiopes is called the "baseline."  It then drops a single line in a "Y" and builds the radials before adding the sticky web.  Most lose stickiness after a day and are eaten by the spider who then, in the ultimate in recycling, uses the ingested silk to reconstruct the web.  Details and diagrams of their techniques are at  When most prey hits the web, the spider rushes out and bites it, killing it before its thrashing allows it to escape.  With some venomous insects like wasps they just carefully wrap it in silk.

Whether you like Latin names or not, the name Argiope aurantia is necessary to confidently identify the species.  Using "binomial nomenclature" creates a universal name recognized in all languages. Between three different authoritative sources it carries the common names of writing spider, corn spider, black and yellow garden spider, zipper spider, banana spider, x spider, corn spider, the yellow and black garden spider, the black and yellow argiope, the golden orb weaver, and yellow argiope.  This impressive list demonstrates the importance of a scientific Latin name.

The story of a female spider eating the male after mating is a familiar one in many species (see black widow blog). The Argiope is different.  The male effectively commits suicide by sex. Spiders transfer their sperm to females using their specialized palps which the male inserts into the female.  In the case Argiopes, they die right after inserting their second palp, their heart stops beating several minutes later.  This gives a whole new meaning to Rogers and Hart's lyric, "...and my heart stood still."

The second palp remains inserted into the female, effectively plugging the opening and preserving the male's genes from contamination from another male. In other words, he makes the ultimate sacrifice to preserve his inheritance.*
The male’s death is also described as an “irreversible seizure” and apparently this takes place to form a kind of “chastity belt” (James 2003*). Once the male Kamikaze has inserted the second palp, he’s stuck, despite what the surrounding males would like. "The other males go berserk, bite into the legs and try to pull him off." Securing himself inside of her also gives the male’s sperm sufficient time to fertilize the eggs.**
Meanwhile the female never gets to enjoy her 1000+ kids.  She makes a round brown egg sac, attaches it to the web and watches over it.  The spiderlings hatch but the newborn spiderlings remain in the sac over winter while she dies.  They will emerge in the spring to spread out into new territory.  I wonder if the thought of raising 1000 kids is what kills her?

"Bug Eric" Eaton's blog
*    See this NIH publication.
**  Comprehensive A. aurantia information with references is at this link.

More photographs in Bugguide.

Tuesday, September 17, 2019

Life on a Spicebush

Life on a spicebush leaf -Tonya Smith
I borrowed these photographs from Tonya Smith MN who has recently become addicted to macro photography.  Recovery is seldom possible so I am using this blog as a warning to others who might be spared.  She found this on a spicebush leaf and sent it in to Bugguide on September 5th as a Bug Track.  On the 10th, she had this reply.
"This is a row of eggs inserted under the leaf epidermis. The little lid-like appendage at the top of each one suggests Heteroptera, and my first guess is Miridae (plant bugs), but I don't have any experience with their eggs, so it would be great if you could collect the leaf and see what pops out. Great photos!"… Charley Eiseman, 10 September, 2019 - 5:49am
Closeup with "lid-like appendage on top" - Tonya Smith
There are several lessons to be learned here.  First, there is a community of fellow "macrophiles" out there who are willing to give a helping hand, although some like me can be wrong at times.  Charley Eiseman, quoted above, is the guru and has helped me out several times and is generous with his expertise.  After years of assisting me in my gall addiction, he has ventured into life "in a leaf."

Leaf miner on Verbesina virginica - REK
While chasing chasing tiny critters on leaves I frequently see these scars.  They may occur on the upper or lower surface, sometimes on both.  I had always assumed that they were caused by something browsing the epithelium but it turns out to be something much more interesting. 
A leaf miner is any one of numerous species of insects in which the larval stage lives in, and eats, the leaf tissue of plants. The vast majority of leaf-mining insects are moths (Lepidoptera), sawflies (Symphyta, close relatives of wasps), and flies (Diptera), though some beetles also exhibit this behavior.  Wikipedia
Leaf miner tunnels with trails of frass - REK
Note that it says "lives in."  These tiny larvae mine in between the upper and lower surface epithelium, frequently leaving little tiny strings of dark frass (insect poop).  Eventually they emerge, leaving through a small exit hole which you may see under magnification.

If you want to pursue leaf miners beyond the Wikipedia reference, Charley has just published  Leafminers of North America.  It is 1857 pages long (plus a 54-page table of contents, 20-page glossary, and 68-page bibliography), illustrated with thousands of color photographs.  To prevent injury to the UPS delivery drivers it is only available as an ebook but it is a great reference.  "Abandon all hope, ye who enter there" for I have sampled the incredible deep dive into my copy and it is hard to emerge.

He and Noah Charney wrote Tracks & Sign of Insects and Other Invertebrates which is an indispensable book for those who wander through nature wondering "what made that?" be it a gall, egg case, pupae, exuviae or an engraving left by an insect. 

Sunday, September 15, 2019

Little Stinkpot

Saturday's field school for the Master Naturalist training class turned up a cool cold-blooded specimen in the creek, an eastern musk turtle, Sternotherus odoratus, the smallest Missouri turtle and one of the smallest on the planetOdoratus is Latin for "fragrant" and its alternate common name of stinkpot sounds ominous.  This is because of scent glands from the edge of its shell which can release a foul musky odor. possibly to deter predation.  Realizing that these were naturalists, it held its fire (or maybe he was just too young for his hormones to arrive.)

"Just call me spike."
Working with the WOLF School, the students almost always give a name to a turtle, snake or even a worm.  I tend to refer to specimens I pick up as "he," a trait that frequently gets me in trouble with my wife.  In this case I am justified as Wikipedia says that "males can usually be distinguished from females by their significantly longer tails and by the spike that protrudes at the end of the tail.

This is a very wise looking turtle, somewhat anthropomorphic but said with affection.  The MDC Discover Nature Field Guide described it this way.  "There are normally two thin, yellow stripes on each side of the head and neck. Small projections of the skin called barbels are present on the chin and throat."  To me it looks like it missed a few spots on its chin while shaving.  Technical note: even male turtles do not shave.

The MDC Field Guide describes its diet writing "A variety of small aquatic animals are eaten by this small reptile, including aquatic insects, earthworms, crayfish, fish eggs, minnows, tadpoles, algae, and dead animals."
"This species is most abundant in slow-current sections of rivers and larger streams of the Ozarks, the swamps, sloughs, and small ditches of the Bootheel, and in a few rivers in the northeastern part of the state. They can also be found in reservoirs. It favors shallow water but also basks on logs, rocks, or small, horizontal tree trunks"
You can't buy Master Naturalist fun like this!  Photos by Becky Swearingen.
For more details go to this link.