Sexton Beetle and Friends

The Creator, if He exists, has “an inordinate fondness for beetles
-Haldane 

It is not every day that I can find a new beetle and identify it.  As Haldane alluded to above, there are more varieties of beetles than any other insect, with over 24,000 species in the United States alone.  Of all living species including plants, one out of five is a beetle.  Therefore, only the most distinctive species can be identified by an amateur naturalist. 
A ride across the field just at dark with an open butterfly net yielded an unexpected find.  This distinctive beetle had orange spots on its hard outer wings and short antennas with orange tipped knobs on the end.  Its abdomen came to a point, unusual for most beetles. Also, he stinks like rotting meat when you sniff him.
Click on pictures to enlarge.

Nicrophorus orbicollis

After letting him chill in the refrigerator, I inspected him with a magnifier and was startled to find eight bright orange mites crawling over the ventral thorax between its legs.  The next morning they were in the same location, showing no signs of wandering off.
Thumbing through insect field guides, I hit upon the identical creature, a carrion beetle in the genus  Nicrophorus.  It is also called a sexton or burying beetle.  While they are usually found around dead animals, my friend had apparently been on a crepuscular cruise, looking for love in one of the wrong places.
The male and female of this genus typically dig under a dead animal. until it sinks into the ground, thus burying for larval food.  They remove the skin and hair, leaving a tasty meatball for the kids to come.  When the larva hatch they are fed pieces by the adults.
German researchers have noted that beetles will fight to decide which one gets the carcass.  The loser frequently will lay its eggs anyway and some of the time the winner will raise some of those larva as its own.  This is called brood parasitism and its best known example in the USA is the cowbird.
Searching by "Necrophorus mites" I came up with the answer for its orange friends.  Many of these beetles carry mites with them to the next dead animal.  As they compete with fly maggots for their tasty treat, taking along mites that will feed on the maggots helps cut down on competition.  The mites sometimes feed on the beetle's larva as well.  So what is the over-all advantage in carrying the mites?  The rest of the story is told in this paper by Karen Wilson of Colorado State University.

"The benefits to the mite are obvious. They feed on the carcass, fly eggs, and in some cases, eggs of the beetle that carry it. They also benefit in dispersal. The benefits to the beetle may be less apparent initially and some costs are involved. In the presence of flies, reproduction of the beetle was shown to be dependent on the presence of certain mites, especially when repeated infestation by flies was a problem. they decrease brood size and increase larval weight. The mites also reduce colonization of the carcass by soil microbes. It is unclear as to whether or not the increase in individual larval size is a true advantage over large brood size. However, larger individuals are more successful in competitive situations and therefore may have a long-term competitive edge."

Remember that in most species that fight over sexual favors or breeding sites, the bigger bug wins.  Carrying a few mites on your chest seems to be a small price to pay for raising the biggest kids on the block
I believe that this is Nicrophorus orbicollis, as described at Insects of West Virginia and Wikipedia.

Northern Water Snake

One of the permanent resident species on Bull Creek is the Northern Water Snake.  Visitors frequently are alarmed at the sight of "a copperhead in your swimming hole."  They are frequently confused because of similar coloration but the water snakes neck bands are complete rather than the "Hershey Kisses" pattern of a copperhead.  They tend to darken with age.
They are frequently found patrolling the edges of the stream, cruising in and out of underwater rock crevices in search of crawdads and small fish, or anything else they can get their mouths around.  Wikipedia says they can also project themselves out of the water, up to 2 m in height to attack prey such as small birds and insects.
Like many snakes, they will bite if threatened and release excrement and musk as a further deterrent.  Their saliva contains a mild anticoagulant, which can cause the bite to bleed more but poses little risk to humans.
Our friend pictured here was found by our neighbor Larry Whiteley.  It was just starting to devour a perch head first.  By the time we went back for a camera it was almost done, with just the tail protruding from its mouth.  With its jaw displaced for swallowing, the head had an ominous triangular shape but the pupil was round, not to be confused with a venomous water moccasin.

Copperhead out for a swim

Speaking of Hershey Kisses, for years I have been reassuring neighbors that if it is swimming in the creek, it isn't a copperhead so leave it alone.  Then several years ago, a friend was at the creek crossing and got this picture.  The copperhead was crossing at the shallows but was proving the exception to my rule.  It pays to observe carefully.  Click on the pictures for a larger view.

A good resource for the Snakes of Missouri is on this Missouri Department of Conservation web page.

Water Matters

Water, water, everywhere; Nor any drop to drink. 

                         - The Rime of the Ancient Mariner

Water figured in two articles in Thursday's News-Leader.  Francis Skalicky described the Missouri Stream Team program with 4,000 teams monitoring 100,000 miles of streams.  Much of their labor involves picking up trash from stream beds and banks.
More subtle damage occurs from excess nitrogen and phosphorus in the streams.  This encourages excessive plant and algae growth that in turn depletes dissolved oxygen levels in streams. Depleted dissolved oxygen levels can lead to fish die-offs and problems for other stream organisms.
The pollution comes from excessive fertilization of lawns and pastures, byproducts of animal treatment operations with inadequate waste-removal facilities, and poorly functioning septic systems.  Stream team monitoring can detect patterns that helps government and environmental agencies develop management plans for watershed areas.
A more dramatic reason for monitoring our streams is in the News-Leader story on beach closings due to high levels of E. coli.  These occurred at Pomme de Terre State Park, Lake of the Ozarks State Park, Mark Twain State Park, and Crowder State Park.  While stream teams do not do bacteriologic monitoring, their data on pollution can help pinpoint pollution sources.
Stream Teams also get their hands dirty while cleaning up trash along the streams.  On our Master Naturalist Upper Swan Creek team's last trip they either completed another cleanup or they were trying to get a hand-held hillbilly satellite dish set up.
From their pictures, the team apparently included a Prairie Ring-necked Snake.  They are easily recognizable by their small size, uniform dark color on the back, bright yellow-orange belly and distinct yellow ring around the neck. They take shelter under rocks where they find worms, slugs, soft bodied insects and small salamanders.  Since Ringnecks live on rocky, wooded hillsides, they aren't much help in keeping our streams clean.  That requires people like our stream team, so hats off to them.  You can help by joining Stream Team activities.
More information on the Ring-neck is on the Non-venomous Snakes page of the MDC website.

Bird Drop Caterpillars.

Japanese research has identified a hormone that allows some caterpillars to change protective coloration from a bird dropping (like our Giant Swallowtail pictured below) to the color of the leaf they live on.  (see Reuters picture on right)

"A special hormone -- juvenile hormone -- keeps larvae of the butterfly Papilio xuthus, which is commonly found in Japan, in their black and white bird-excrement camouflage.  As they reach the last stage of caterpillar development, levels of this hormone drop, triggering a transformation into the green leaf phase.

Juvenile hormones are known to regulate many aspects of insect development including molt -- when an insect sheds its outer shell -- and metamorphosis -- as when a caterpillar becomes a butterfly, he said."

Our Spicebush Swallowtail has a similar conversion in its final instar (larva) and posibly could share this mechanism.  The common Giant Swallowtail Butterfly (Papilio cresphontes) which I mentioned in the May 19th blog is in the same genus, but doesn't change color in the final instar.  (Picture from Whatsthatbug.com)  The large bird poop-like caterpillar is famous for its prominent stink glands, called osmetria, which protrude when it is threatened.  This appearance has given it the name "Orange Dog".  There is a lot of information on its entire life cycle at mybutterflyguide.com.
There will be multiple stages of the Giant Swallowtail's life cycle available at the Butterfly House at Close Gardens.

Millipede

Larry Whiteley (yes, the Bass Pro one) came up with this millipede.  Insect identification used to be difficult to impossible but the Internet has made it easier- or has it?  Insect experts (entomologists), like botanists, frequently debate species and come up with new names, seemingly to confuse those of us in the laity.
You can see a similar creature at Whatsthat bug.com which is identified as a flat-backed millipede in the Polydesmida order, subsequently modified to Apheloria tigana Chamberlin, 1939 (Polydesmida: Xystodesmidae).  They reassure us that "many species like this secrete a cyanide compound to defend themselves. As long as you don’t eat one or lick it, you should survive.”.  Wikipedia confirms that "members of this order have the ability to produce hydrogen cyanide to ward off predators. 
The posting in Bugguide.net illustrates the some of the problems in identification. Here it is identified as "probably a species of Harpaphe". a subsequent expert opinion states "This may be Harapaphe haydeniana but I am not sure with the color variation in the paranota".
Satisfied with the Harpaphe family, more information is available at Wikipedia. Its cousin, Harpaphe haydeniana (Yellow-spotted millipede or cyanide millipede) has similar characteristics. The family produces cyanide and you have to be careful in handling it. (Don't lick it Larry!) They break down leaf litter, producing soil and nutrients for other organisms.
Millipedes are vegetarians,distinguished by having 2 pair of legs per segment rather than one pair like the predatory centipedes. Even this generalization breaks down as this genus has only one pair of legs in the seventh segment, the other pair having been transformed into gonopods for sperm transfer. Didn't Adam give up a rib for the same cause?
There are way to many bugs on the planet to rely on color and the number of legs. Even the aficionados of the sport of entomology can be stifled without examining the detail of microscopic parts. We interested naturalists may have to be satisfied with a few generalizations. To me, its a Flat-backed Millipede- period!
An excellent resource from the Kansas School Naturalist is available at this site.

P.S.
Thanks to Dr. Chris Barnhart for contacting Neal Youngstead who studies millipedes.  He has a pair of similar appearing millipedes which have not reproduced.  He says

"I have no specific identification for them; Polydesmida, Xystodesmidae, is as far as I can go, but I have not really tried to go farther. This usually gets into the realm of the taxonomic specialist before the species level. The attached paper may be of interest and the photos show how similar some of the species can be."

  (See the pictures on page 2 of the PDF in the right hand column of this PNAS- Procedings of the National Academy of Science
site.
Like I said- Flat-backed Millipede.

Birds by Ear

Some of us are challenged by bird songs and calls.  I have learned the difference between a crow call and a cardinal but am pretty much stuck at that level.  Fortunately, George Deatz of Friends of the Garden introduced me to an exciting new web site. 
Dendroica- An aid to identifying North American birds list 643 species of birds with multiple pictures and simultaneous bird songs to identify them.  This is richer in songs than other sites and easier to use.  On the downside, there is no other information about the birds.  It includes a quiz function which is far too sophisticated for me at present.  You need to complete the free registration to obtain your user name and password.  Note: I have added this site to our Resources page.
The most encyclopedic source on birds is the old standard, Allaboutbirds.org from Cornell Lab of Ornithology.  Over the last year it has undergone some structural changes, making it even easier to use.
The difference between bird songs and calls is described at all-birds.com.
They point out that the more musically complex songs are usually produced only by the male. Since they often learn these songs from their dads or by listening to nearby males, regional dialects are often developed. The male’s song may improve with age, enabling him to attract more female attention (unlike most human males.)
There is nothing like going out with an experienced birder.  Charlie Burwick, aka. "Hawkowl", was at Camp Arrowhead last month, leading a group of scouts preparing for their Birding merit badge.  This is a highly productive, low tech and low cost approach.  That is unless you have to buy him lunch.
Finally, technology has stepped it to help.  Birdjam has an app for your iPhone or iPod Touch to identify sounds, birders can use playback sounds to call up birds, and some birders have specialized in recording songs and calls for identification.
Personally, I am waiting until my phone lets the birds call in and their name shows up on the screen.

Jumping bristletail

Ever wonder what turns a Master Naturalist on?  Chapter members who came early for the Rotten Log presentation were excited to find one of the oldest and least evolved animals on the planet.  No, I am not referring to chronologically advanced members, but to the Jumping Bristletail  we found within the log.
These primative creatures evolved in the Devonian period according to Wikipedia.  At that time over 350 million years ago, fish were first developing legs and huge seed-bearing plants were starting to cover the supercontinent of Gondwana.  Since they feed on algae and mosses and are usually found in leaf litter and decayed vegetation, the abundance of forest must have provided a great niche for them to prosper.
According to UC Berkeley Biokeys, they do not have wings, they have long segmented antennae, and they have 3 cerci coming out of the end of the abdomen.  ((Our friend modestly held them closely together for the picture)  Jumping bristletails can spring up into the air as much as 10 centimeters by flexing their abdomens as we discovered while getting the picture.
I am happy to say he is back in his rotted log with a story to tell his sow bug and millipede neighbors .

Butterfly House

The Bill Roston Butterfly House at Nathanael Greene/Close Memorial Park is completed and open on weekends.  The story with pictures is in the News-Leader.  The first butterfly was actually a volunteer Buckeye butterfly which flew in while they were putting on the cover and decided to stay.
  All the butterflies are native species, but we bring in chrysalis (pupa) from a Florida butterfly farm to get started.  Most days there are butterflies emerging, a mixture of Red Admiral, Gulf Fritillary, Giant Swallowtail, Painted Ladies and Monarchs.
Pictured is a Giant Swallowtail Caterpillar, photographed in the house by Linda Kittle.  It which is just about to pupate, the last step in the miracle of metamorphosis into a beautiful butterfly.  In her words, "he has himself all harnessed up to a citrus tree to begin preparation for his grand finale."  How did she know that it was a male?

"I watched him for some time.  He made several trips around and around the top of the plant pot before finally climbed up to the location where he eventually tied off.  Not once did “he” stop to ask for directions."

This caterpillar is remarkable in its resemblance to a bird dropping.  This protective coloration tends to dissuade all but the most ravenous predator.  A caterpillar is essentially the "eat and grow" phase of butterfly metamorphosis.  Since it doesn't have to find a seduce a mate or reproduce, its appearance has no drawback to its lifestyle. 
We are now bringing in butterflies captured "in the wild" for the Butterfly House.  Bull Creek specimens included Gray Hairstreaks, Eastern Tiger Swallowtail, Wood Nymphs, Silver Spotted Skippers, a great Spangled Fritillary and lots of Pipevine Swallowtails.
The Butterfly House will be open 10AM-6PM on weekends with weekday evenings planned this summer.  Bring a camera and, if possible, a child to fully experience the wonders.

Master Naturalists at Work

What do you have when you put 1000 native shrubs, 700 native plants and a bunch of shovels together with the new grade school?  If you guessed mayhem or fun, you are correct.  Jay Barber and Mort Shurtz have been working over the last month with students and teachers on extensive plantings around Hickory Hills school.  The students are doing the planting after lots of adult shovel work, combining energy and enthusiasm in all kinds of weather.
This kind of program, supported by the Missouri Department of Conservation and Master Gardeners, helps teach the importance of native plants in our environment.  Students will get to see their efforts grow and can come back in future years to see the results.
While the kids may have learned about planting shrubs and conservation, our intrepid crew came out with a better understanding of Chaos Theory.

Pipevine Butterflies

It is butterfly season in the Ozarks and the Pipevine Swallowtails are fluttering around Bull Creek.
Butterflies lay their eggs on a very specific host plant that is necessary for their larva to feed upon.  Pipevine Swallowtails lay their eggs on Pipevine (Aristolochia species) including Dutchman's Pipe (A. tomentosa and Virginia Snakeroot (A. serpentaria).  We have been searching for pipevine plants with little success but apparently the butterflies are much better at it than we are as they are thriving.

Pipevine plants have a nasty tasting chemical that is retained by the caterpillar and the adult butterfly.  A predator is likely to get sick from sampling one and apparently learns from the experience.  Black Swallowtail and Red-Spotted Purple butterflies, which are non-toxic, have a similar appearance and predators avoid them as well, a benefit called mimicry. In Pipevine Swallowtail territory, Eastern Tiger swallowtail females develop a similar dark coloration, while the same females in other areas are light colored like the males. 

All swallowtails come equipped "osmeterium", brightly-colored, horns which they extend from their heads when bothered.  They can rear back and almost touch their tail, secreting a foul smell which turns off predators.  (See Patrick Coin's picture with the orange horns.)

The Bill Roston Butterfly House is opening this weekend at Close Memorial Park.  It is stocked with a wide variety of native butterflies with more added weekly.  You can see all stages of their life cycle on most days as they lay their eggs and raise their caterpillars.

There is a fantastic set of pictures by Patrick Coin, showing the complete life cycle of the Pipevine Swallowtail butterfly at this Flickr.com web site.  A wide range of his nature photographs are found at Flicker collections.  Fair Warning: Addicting- don't enter unless you have time to spare!

The Sun Fuels Life

The News-Leader printed Photosynthesis Key to Life in its education page.  This feature intended for young students has a lot of lessons for all of us.  Virtually all life except those in the deepest ocean vents derives its energy from photosynthesis.  Even these require the sun to prevent the oceans from freezing.
Many ancient peoples worshiped a Sun God.  While their theology is quite debatable, they were on to something long before the study of biology developed.  Our world is a closed system.  All of our resources are currently enclosed within our planet. The only energy which comes from outside the planet earth is the sun.
The sun's rays are the key ingredient in photosynthesis.  Without its constant bombardment of energy, the planet would freeze leaving no rain or available water.  Wind energy depends on changes in air temperature created by the sun.
All of our current economic system is based on growth and competitive pricing of resources.  If there is a shortage of anything, the price goes up, creating the incentive to produce more.  Provide excess production and the price goes down.
This works well as long as the resources are available.  Unfortunately, there is no more water on the planet now than was present before the dinosaurs.  Oil and natural gas are only produced slowly over millions of years by the death and prolonged burial of carbon based plants and animals. 
In recent decades we have started to seriously strain the world's bank account of energy and water.  Herman E. Daly explains the problem in his short article, Economics in a Full World.  He gives a simple explanation of the situation we face "in a world where the economic mantra is growth without consideration of the inability to expand beyond our planet for additional resources."

Relying on growth in this way might be fine if the global economy existed in a void, but it does not.  Rather the economy is a subsystem of the finite biosphere that supports it. When the economy's expansion encroaches too much on its surrounding ecosystem, we will begin to sacrifice natural capital (such as fish, minerals and fossil fuels) that is worth more than the man-made capital (such as roads, factories and appliances) added by the growth.  We will then have what I call uneconomic growth, producing "bads" faster than goods--making us poorer, not richer.

Once we pass the optimal scale, growth becomes stupid in the short run and impossible to maintain in the long run. Evidence suggests that the U.S. may already have entered the uneconomic growth phase. Scientific American-2005

I would recommend that you download and read the PDF file Economics in a Full World.  For a more complete but clear understanding of economics past and future, Daly's 1997 book, Beyond Growth: The Economics of Sustainable Development is a good resource.

Kudzu Therapy

I wanted to share the article in Thursday's News-Leader on kudzu so I went to their home page and searched for it.  The article came up right under ads for Kudzu.  I could conveniently buy Kudzu Root Supplement for $5.49 or Standardized Kudzu as a source of calcium for vegetarians.  Kudzu!  Who knew?
It turns out that Kudzu was used in China for migraine, hypertension, arthritis and dependence on alcohol.  Chinese studies on alcohol intoxicated rats showed that rats given Kudzu tea appeared to be less intoxicated than their tea-less brothers.  Apparently intoxicated rats are a problem in China, although their source of booze isn't discussed.  This may explain the rattling and scraping sounds we hear at night in the walls of our place on Bull Creek, accompanied by and occasional tiny voice saying "Party on, dude!"
Having scoffed at this, I then saw that one ad referred to a Harvard study.  To my chagrin, a little research yielded an article in Scienceblog.com confirming that their research "report that moderately heavy drinkers given the herb extract in capsule form for a week before taking part in a drinking experiment consumed significantly fewer beers than those who got a placebo- almost by half".
None of this affects the concern about Kudzu as an invasive species.  It has been seen in several areas in Christian county and is probably in other areas that haven't been reported.  It seems to have a preference for forest edges, abandoned fields, roadsides and disturbed areas where sunlight is abundant.
The News-Leader article from MDC has all the facts in one place.  The story of the "Vine that ate the South" began with what seemed to be a good idea, a rapidly growing vine promoted for forage and erosion control.  We should be cautious about any plant whose apparent virtue is rapid growth without any upkeep required.
To learn how to cook with Kudzu and make kudzu paper go to Kudzu Kabin Designs, courtesy of Mimi Aumann.  More information on it's use as an alternative medicine is at Drugs.com.
Now, how are we going to to get those Kudzu roots to the rats behind the baseboards?

Bees are Elephant Repellant

A elephant story in today's News-Leader caught my attention.  It reports that elephants are afraid of bees, leaving the area when they find them and warning other elephants nearby.
Lucy King and colleagues report in PLOS that "the sound of disturbed African honeybees Apis meliffera scutellata causes African elephants Loxodonta africana to retreat and produce warning vocalizations that lead other elephants to join the flight."
They used special audio recording devices to record the elephants distinctive "rumble" vocalizations which are below the human hearing range.

"Audio playbacks of bee sounds induced elephants to retreat and elicited more head-shaking and dusting, reactive behaviors that may prevent bee stings, compared to white noise control playbacks. Most importantly, elephants produced distinctive “rumble” vocalizations in response to bee sounds. These rumbles exhibited an upward shift in the second formant location, which implies active vocal tract modulation, compared to rumbles made in response to white noise playbacks. In a second experiment, audio playbacks of these rumbles produced in response to bees elicited increased head shaking, and further and faster retreat behavior in other elephants, compared to control rumble playbacks with lower second formant frequencies."

In addition to advancing our understanding of elephant behavior, these findings may have a practical implication.  A single elephant can destroy an African farmer's gardens and his livelihood in a single night.   They frequently have to guard their plots at night, hoping to scare the elephant away, a dangerous and frequently futile action.  In addition, frustrated farmers frequently kill elephants which is against the law.
A possible application of this research would be to create "bee fences".  Bee hives would be attached to posts connected to each other by wire.  When the elephant hits the wire, the sound of the disturbed bees would alarm the elephant and drive it away.
Unfortunately, this has no apparent application for the raccoons and rabbits in our vegetable garden.

The article appeared in PLOSone.com (Public Library of Science) which is an online peer-reviewed science journal.  The science is high quality and an open access source, meaning you can read the whole article without having to pay to access it.  While usually quite technical, they have a lot of interesting scientific studies.

Orchids by GPS

The Missouri Native Plant Society (MoNPS) has formed a chapter in Springfield and are off to a good start.   Their President Larry Wegmann sent me these pictures from their trip to Pickle Spring in Southeast Missouri.  We have hiked the trail through the canyon in the winter, but Larry's trip was to find the elusive Isotria orchid.  They searched the area where they had previously found without results.  Finally one menber took out his GPS for a reading and saw them just in front of the unit!  (See below) Finding orchids by GPS- that is what I call a scientific method.

Earlier they had found the cluster of Southern Lady Slipper Orchids below at Hawn State Park.  If this type of adventure appeals to you, I would encourage you to try attending the MoNPS meetings.

MoNPS meets at 6 PM, the second Tuesday of the month at the Nature Center, although that may change in the future after the Botanical Center opens this fall.  Membership is free and all are welcome to attend.

Buck Did It Again!

Our own Master Naturalist, Buck Keagy, is a man of wide and varied talents.  After watching him demonstrate his taxidermy skills by completing an owl mount in 45 minutes in front of a crowd while providing constant banter, you would think that we couldn't be surprised with any thing he did.
Wrong!  Last month he made a very forceful presentation (does he do another kind?) to the Friends of the Garden Board about a design in flowers that he proposed (insisted) on making in front of the Butterfly House at close Memorial Park.  Fortunately the Board approved idea with enthusiasm, as I don't know any way of stopping Buck.

Now several weeks later he has laid out the design in rock, ordered and planted the flowers and completed the project.  You can see it all the way across the park from the parking lot.  Built on an angle, he designed it to maintain the proportions when viewed from a distance.
Knowing Buck, it will probably fly off in a few days to lay eggs.  If it doesn't, look for it at the opening of the Butterfly House on May 15th.  It isn't too late to volunteer for the docent group.  Training is on May 12th.

Gall Bites Man

Headline of Gall Bites Man?  Well not exactly.  But as Tim Gibb, a Purdue Extension entomologist, reported in 2007 an oak gall mite can cause a chigger-like reaction when it bites humans.  Formally known as Pyemotes herfsi, it is a parasite of a parasite.  Confused yet?  Stick with me.

A midge lays its egg on a pin oak and its egg produces the gall which harbors the insect larva.  The mite comes along and lays its egg, parasitizing the midge larva.  While the mite is known to attack this oak leaf gall, entomologists suspect it affects other gall larva as well.
This is all ready confusing enough but hang on.  "When there are not enough insects acting as hosts for the mites, humans and animals become secondary hosts.  These mites do not carry diseases and are very similar to chiggers.  They are strictly a nuisance and there is no need to stop outdoor activities."
It looks really threatening in the picture, but don't bother searching your body for it.  It is only 0.2 mm long, the equivalent of three human hair widths.  Although possibly spread in the air, the best way to acquire your own mite is by handling the galls.  They tend to attack the hair follicles and pores.

"Most people can't see the mite, but can feel it moving," Gibb said.  "When they get on people, they typically go to pores or hair follicles.
"Once they pick a spot they inject their saliva, which desensitizes the skin around it and then suck lymph from the body.  The person won't know until four- or five-plus hours later when the skin becomes sensitive and develops a rash or welt that itches."

Actually Pyemotes herfsi was identified in 1936 in Europe.  According to an article in Wikipedia the first US outbreak was identified in Kansas City, Kansas in 1992. Although not a serious health hazard, the CDC estimated that 54% of the county residents were affected.  There have been scattered outbreaks since then. 
Humans typically report itching from mite bites within 10 to 16 hours after contact. The victims often do not recall being bitten. The rash that results from the bites is usually described as a red patch with a small blister in the center, most often found on the neck, face, arms, or upper torso.  Washing with soap and water is said to kill the mites.
If you are wondering how they figured all this out, the USDA study makes interesting reading.  Are you feeling a little itch?