Archive for the ‘invertebrates’ Category

The Continent Conquering Human Flea (Pulex irritans)

January 8, 2017

A flea can jump 160 times its own body length–the equivalent of a 6 foot tall human jumping the length of over 3 football fields.  Most of the known 2500 species of fleas are ectoparasites that use this phenomenal jumping ability to leap from the ground to an host or from one host to another.  Scientists believe the human flea was originally a parasite of wild cavies, species of rodents native to South America.  9,000 years ago, South American Indians began domesticating a species of cavy, either Cavia tschudii or C. aperearesulting in the well known household pet, the guinea pig ( C. porcellus ).  The domestication process may have been instigated by the cavies rather than humans.  Cavies likely were attracted to the shelter of human dwellings where they fed on vegetal kitchen scraps.

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The human flea expanded to many times its size. Their toes serve as a lever that helps them jump many times their body length.

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The guinea pig is thought to be the original host of the human flea.  Fur traders spread the flea from South America to North America and across the Bering Strait to Asia.

By 7,000 years ago, guinea pigs were commonly raised in many South American Indian households.  Maintaining a population of 20 individuals yielded about 12 pounds of meat per month, so they served as a valuable source of food, lessening the need to hunt wild animals.  Fleas from guinea pigs made the leap to man and from there they conquered 5 continents.  According to the lead author of the below referenced study, they advanced through a “step by step gift exchange of furs from South to North America and over the Bering Strait.”  Fur traders slept on their skins and left flea larva living in the detritus of flea feces, dried blood, and human skin flakes that accumulated on their unwashed beds.  After mature fleas feed on blood, they lay their eggs in this detritus.  Human fleas were carried along Asian trade routes and they conquered Egypt by 6000 BP.  The Roman armies carried fleas from Egypt to southern Europe, and the Vikings may have carried fleas from North America to northern Europe.

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Roman legions and Vikings carried fleas with them to Europe.  Bubonic plague carried by fleas from rats to humans and back depopulated Europe.  Fleas were responsible for far more deaths than Romans and Vikings.

Human fleas made a colossal impact on human history.  Fleas jumping back and forth between rats and humans spread bubonic plague, a disease that killed an estimated 30%-60% of the European population during the years 1347-1350.  Much of Europe reverted back to wilderness following this depopulation.  The Romans and the Vikings thought they had conquered the world, but they are long gone.  Human fleas are still here and can be found in just about every hotel, even in the finest, most expensive chains.

Reference:

Panagiotakopulo, Eva; and Paul Buckland

“A Thousand Bites–Insect Introductions and Late Holocene Environments”

Quaternary Science Reviews November 2016

Red Rain in India was Caused by a Microorganism from Europe, not Outer Space

May 4, 2016

The Color Out of Space: H.P. Lovecraft One of the first stories I’ve read from Lovecraft. It’s basically about this meteor that falls on some farm property, and everything slowly changes.  While you just chant the whole time “Leave! Move somewhere else!”, they can’t because something bigger is keeping them there. What I really love about Lovecraft is nothing is ever simple and there’s seldom a happy ending.

An unusual meteorological occurrence in India reminds me of my favorite H.P. Lovecraft story–“The Colour out of Space.”

H.P. Lovecraft published the classic science fiction/horror story, “The Colour Out Of Space,” in 1927.  The story is about a meteor that crashes in a farmer’s field and causes strange unnatural changes to all the plants, animals, and people living in the vicinity of the impact zone.   It’s remarkably prescient because the story precedes scientific knowledge of radiation poisoning, and the descriptions of the meteor’s effects bear a resemblance to nuclear fallout, though Lovecraft implies a supernatural explanation.  This work of literature directly influenced the movie, “Five Million Years to Earth,” still often aired on Turner Classic Movies, and Stephen King’s novel The Tommyknockers, his last book written while he was under the influence of cocaine and alcohol.  Some literary analysts make the claim the aliens taking over people’s minds in King’s novel is a metaphor for the drugs taking control of the author before he succumbed to treatment.  (I disagree with Stephen King when he later admitted he thinks this was a bad novel.  I rank it in the upper 25% of his creations.)  Lovecraft’s theme of an alien life form effecting life on earth permeates much of the science fiction/horror genre.  Yet, this idea is not solely confined to the realm of fiction.  Many scientists think life on earth originated in outer space, a concept known as Panspermia.  They believe non-photosynthetic microorganisms, living deep inside meteorites, crash landed on earth and later evolved into all the life forms now existing on the planet.  (The microorganisms would have to have been inside the meteorite because they couldn’t have lived on the surface in space nor could they have survived the friction heat generated by entering earth’s atmosphere.)  Proponents of Panspermia Theory thought they had strong supporting evidence when a strange red rain periodically fell in India for 2 months in 2001.  They examined the rain under a microscope and observed single-celled organisms that appeared to be multiplying but had no apparent DNA.  They assumed the organisms originated in a meteor that broke apart in the atmosphere, releasing the extra-terrestrial spawn.

There have been many incidents of red rain falling in India.  Some scientists proposed this as evidence of  Panspermia.

Genetic tests determined the rain got its color from a species of algae that originated in Austria.

However, a more detailed study of the organisms found in the red rain determined they were a species of algae that lives in symbiosis with a species of European lichen.  A DNA analysis identified the microorganisms as spores of Trentepohlian annulata.  Weather conditions sent airborne spores into clouds blown over the ocean, and they eventually fell as rain on India.  The algae recently colonized lichen growing on Indian rubber trees.  Though this study probably disappoints Panspermia proponents, it does illustrate an amazing case of an organism’s dispersal capability.  The same weather patterns periodically recur–red rain in India has been reported as recently as 2012 and as long ago as 1896.

There may be no hard evidence supporting the Theory of Panspermia, but there is a curious fact about microorganisms in space that lends support to the concept.  Astronauts often discover thick disgusting layers of biofilm growing inside space stations.  The microorganisms were introduced by accidental contamination.   A scientific study showed bacteria reproduce and grow more rapidly in zero gravity conditions, resulting in a greater biomass.  This is especially hazardous for astronauts because the human immune system completely shuts down in zero gravity.  Maybe it’s just a coincidence that simple one-celled organisms thrive in weightless conditions of outer space.  Or maybe they are so well adapted to zero gravity because it is the condition from which they originated.

References:

Bast, Felix; Jackson Adnankunju, and F. Stocker

“European Species of Subaerial Green Algae Trentepohlian annulata (Trentepohliales, Uluphyreae) Caused Blood Rain in Kerala, India”

Journal of Phylogen Evolution Biology Feb 2015

Wouseong, Kim; et. al.

“Spaceflight Promotes Biofilm Formation of Pseudonomous aeriginori

PLOS ONE 2013

Pleistocene Dung Beetles

March 31, 2016

An odd thought occurred to me the other day involving Hindu reincarnation myths and dung beetles.  I happened to jog past a female rainbow scarab beetle (Phanaeus vintex), rolling a dog turd on the asphalt-topped road.  (Female scarab beetles lack the male’s horn, making the sexes easy to distinguish.)  Scarab beetles bury feces and lay their eggs in it.  Both the adults and larva eat shit.  Apparently, this particular scarab beetle was looking for soft earth where it could bury its offspring’s food supply, but it couldn’t find the end of the hard road–it kept rolling the turd in circles.  I felt sorry for the creature because it would roll the turd within inches of the side of the road, almost to the dirt, then it would turn around and roll it toward the other side.  A car ran over the turd, busting it into 3 pieces.  Undeterred, the dung beetle picked the largest piece left and began rolling it in circles again, never quite reaching the dirt for as long as I observed it.  I’m not familiar with the Hindu religion, but I think they believe human spirits can be reincarnated as animals.  Suppose the Hindu Gods punished a human, whose sin during life was laziness, by reincarnating his soul as a dung beetle stuck rolling a heavy turd on a hard surface where it could never find a soft place to rest.  The soul could spend an eternity of hard labor to make up for his earthly slothfulness.  In reality a dung beetle never gets discouraged because insects are automatons with no emotions.  Before man built hard roads the only environment where dung beetles could become indefinitely trapped rolling turds were large granite outcroppings.  Dung beetles are yet another organism suffering a high death toll because of man’s extensive road network.

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I saw this female rainbow scarab beetle rolling a dog turd on the street in front of my house.  It was aimlessly rolling it around in circles.  It just missed getting run over by cars.  Click to enlarge.

There are 3 types of dung utilization behaviors among the many species of dung beetles.  Some take a piece of shit and roll it some distance away from the manure pile before digging a hole and depositing an egg in it.  These dung beetles are known as “rollers” and include members of the Phanaeus genus.  The “tunnelers,” including members of the Onthophagus genus, dig holes adjacent and under the dung pile where they deposit their eggs.  The “dwellers” live and lay their eggs inside the dung pile.  These include members of the Aphodius genus, and they release chemicals that keep the dung patty moist.

It is likely the widespread extinction of megafauna at the end of the Pleistocene caused a drastic reduction in the abundance and diversity of dung beetles.  One study found that the diversity and size of dung beetle species in Africa was higher in regions with abundant populations of megafauna.  Researchers counted 50 species of dung beetles in savannahs where elephants still occurred, 41 species where just cattle ranged, and 30 species in regions with no large mammals.  Dung beetles that switched to donkey shit in regions where elephants became extirpated were reduced in size.

Most species of extinct Pleistocene dung beetles will likely remain unknown to science because the odds of preservation for insects are even lower than those for large vertebrates.  However, 3 extinct species have been recovered from the La Brea Tar Pits in California–Onthophagus everestae, Copris pristinus, and an unnamed species in the Phanaeus genus.  (It’s possible some of these may be extant but undiscovered, but so far no entomologist has found a living specimen.)  The only species of dung beetle found in a preserved mammoth turd is the still extant Aphodius fossor, a large insect found in cow and horse pastures of Eurasia and North America.  Aphodius fossor probably followed herds of megafauna across the Bering land bridge almost 2 million years ago.  The specimen of mammoth dung containing the sub-fossil dung beetle was recovered from Bechan Cave, Utah.  An excavation at Snowmass, Colorado has yielded the remains of 9 species of dung beetles associated with the bones of megafauna dating to 120,000 years BP-77,000 years BP.  Scientists have identified 3 of the species, and they still occur in the region.  The remains of the other 6 species are too fragmentary to positively identify to the species level, but they may or may not represent extinct beetles.  Dung beetles have yet to be discovered from giant ground sloth dung, but fly larva from the Diptera genus, and a fly pupa from the Scairidae family have been found in sloth shit occasionally preserved in caves.  Flies compete with dung beetles.  Some species of dung beetles have evolved to prey on fly larva they capture inside feces.

Aphodius fossor - David Gould - The Spearwort Fields - 06 July 2014

Aphodius fossor, the only species of dung beetle ever found inside mammoth feces, though without a doubt many species were attracted to piles of megafauna shit during the Pleistocene.  The rarity of manure preservation in the fossil record explains the absence of evidence for other species.

Dung Beetle Life Cycle

Life cycle of a dung beetle roller.  Some other species tunnel into dung and lay their eggs inside the patty.

Dung beetles are beneficial organisms that expedite the recycling of nutrients.  The adults and larva also serve as food for birds and mammalian insectivores.  Birds, moles, shrews, skunks, possums, and armadillos apparently don’t mind the taste of the manure-flavored beetle grubs.

References:

Hanski, Ilkka; and Yues Cambefust

Dung Beetle Ecology

Princeton University Press 2014

Krell, Frank-Thorsten

“Pleistocene Dung Beetles from MIS 5 at Ziegler Reservoir, Snowmass Village, Colorado (Coleoptera: Scarabaedae: Aphodine)”

Denver Museum of Nature and Science Annals 2014

Pierce, W. D.

“Fossil Arthropods of California: Descriptions of Dung Beetles (Scarabidae of the Tar Pits”

Bulletin of Southern California Academy of Science 1946

 

Pleistocene Spiders

August 5, 2015

My fascination with the ecology of southeastern North America prior to man’s colonization of the region is frustrating.  Most of the data dating to this time period has been lost to the ravages of time.  I can make educated guesses about the appearance of pristine landscapes untrammeled by man, but this is little better than conjecture based on the pollen and fossil records from a handful of sites.  Many species of plants produce so little pollen they don’t even register in samples collected by palynologists.  And the pollen that is recovered usually can’t be identified below the genera level.  So we know that pine may have produced up to 50% of the pollen at 1 site during a certain time span, but we don’t know whether it was from jack pine, a cool climate species, or longleaf pine, a denizen of warm climates.  But at least we have some data about Pleistocene plant composition.  There are thousands of species of spiders living in the south today, yet I’m unaware of a single Pleistocene-aged site in southeastern North America where the remains of spiders have been recovered.  Spiders have been a vital part of land ecosystems ever since life crept out of the sea.  Nevertheless, there is no evidence of spider species composition dating to the Pleistocene.  Spiders are soft bodied creatures, and their remains get crushed into dust over time.  The remains of hard-shelled beetles, millipedes, and snails have been found in cave deposits located in the southern Appalachians because their hard exoskeletons can remain intact for millennia.  Spiders were also certainly abundant in caves during the Pleistocene, but evidence of their presence is gone.

It’s unfortunate that we know nothing about spider species composition and distribution in the south during the Pleistocene. Even modern spiders are poorly known. There are over 120,000 species of spiders in the world, but only a tiny fraction of these have been studied in detail.  The vast majority of spider species have yet to be described and named in the scientific literature.  Spiders vastly outnumber the scientists willing to study them. Spiders have high rates of reproduction, and therefore evolve rapidly, making them an ideal candidate for an evolutionary biologist to study.  During the Pleistocene many present day species already existed, but there may have been some now extinct species.  Some were evolutionary ancestors of present day species, while others may have left no descendants.  The abundance of certain species varies annually for unknown reasons, perhaps chance.  Below are some interesting species of spiders.

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Artist’s depiction of a trapdoor spider (Ummidia sp.).  I can usually find 1 of these when I dig in my garden.

Common garden spider aka black and yellow argiope (Argiope aurantia).  They build big beautiful webs capable of catching small birds and bats.  Some natives use orb-weaver webs as fishing nets.  Spider webbing is incredibly strong.

Green lynx spiders  (Peucetian viridans) are beneficial for gardeners.  This individual caught a moth.  The larva of some species of moth eat through garden vegetables.

Spined Micrathena, Micrathena gracilis

A spined micrathena (Micrathena gracilis).

Diet of elusive red widow spider revealed by MU biologist

The red widow spider (Latrodectus bishop) lives in the Florida sandhills and feeds upon beetles.

The red widow spider inhabits the pine sandhills of Florida which were islands surrounded by ocean during the marine highstands of Pliocene and Pleistocene warm climate phases.  They construct funnel webs in rolled up palmetto leaves.  This ancient species specializes in capturing flying scarab beetles. The beetles fly low to avoid bat and common nighthawk (Chordeiles minor) predation, but this strategy makes them more likely to fly into red widow spider webs.  Red widows are related to the more common black widow spiders.  They exist as a relic population today but were likely more common when sand scrub habitat prevailed in the south during the late Pliocene/early Pleistocene.

The ancestor of spiders was closely related to the horseshoe crab.  It colonized land about 400 million years ago.  Fossil remains of spiders and spider webs dating to the Cretaceous (~100 million years BP) have been found.  Some were preserved in amber, and others were fossilized in layers of ash that turned to rock.  Though the Cretaceous species are extinct, scientists classify them as belonging to extant genera.

Earth will undoubtedly host spiders long after Homo sapiens becomes extinct.  The drastic changes man has wrought to the environment have barely phased spiders.  Compared to the changes spiders have seen over the 400 million years of their existence, anthropogenic effects are but a minor blip.  Look around, there are spiders inside your house now.

Reference:

Carrell, James; and Mark Deyrup

“Red Widow Spiders (Araneae: Theridiidae) Prey Extensively on Scarab Beetles Endemic in Florida Scrub”

Florida Entomologist 97 (1) March 2014

Pleistocene Pollinators

June 12, 2015

The media sure likes to generate panic.  It must be good for ratings.  Recently, American media outlets offered wall-to-wall coverage of the Ebola virus, a danger that eventually killed 2 or 3 people in the United States from a population of over 300 million.  During slow news cycles the media seems to always find some obscure disease of the month to fill air time.  Another constant well of media anxiety is anthropogenic-influenced climate change, even though its worst effects won’t be felt in our lifetimes, and there’s nothing we can do about it, unless people are willing to give up affordable electricity and cars.  A few years ago, media pundits started peeing in their pants about colony collapse disorder.  Without honeybees (Apis mellifera) they claimed there would be no pollination of fruits, nuts, and vegetables.   The world would have no fresh produce, and we’d be stuck with a boring diet of wind-pollinated grains.  In some regions their fear has come true.  In upstate New York colony collapse disorder wiped out so many honeybees, bee keepers were unable to provide any hives to help pollinate some apple orchards.  There was no loss of production. Orchards produced just as many apples without honeybees as they did with them.  Orchardists realized they’d been duped for decades by bee keepers into thinking they couldn’t grow fruit without paying for the rental of bee hives.

There are 140 species of native leaf cutter bees, including the blue orchard bee (Osmia lignaria), a species that is considered a better pollinator than non-native honeybees.  Moreover, there are many species of native bumblebees, butterflies, and wasps that pollinate flowers.  Native bees are such effective pollinators that honeybees were not missed at all.  As long as some natural areas are left in the vicinity of gardens and orchards, there will always be enough native pollinating insects; and honeybees will be completely unnecessary.  No need to worry about colony collapse disorder–many species of native bees are solitary and don’t nest in colonies.

Osmia-lignaria----WEB

Blue orchard bees are more effective pollinators than honey bees.

Southeastern blueberry bees and bumble bees pollinate my blueberry bushes.

Bumble Bee Queen

Bumblebee (Bombus impatiens)

I marvel at the lack of critical thinking among reporters and media pundits who are so quick to form opinions without realizing how illogical their conclusions are.  Europeans brought honeybees to North America 400 years ago, but before then, Native Americans successfully grew fruits and vegetables dependent upon insect pollination.  They farmed squash, beans, tomatoes, peppers, and plums.  Honeybees are just 1 species out of thousands of insect pollinators in America, yet the media know-it-alls led people to believe a nightmare scenario of no fruits or vegetables.  Not a single pundit during the panic of colony collapse disorder even realized honeybees are a non-native invasive species.  Usually, invasive species are another topic of unnecessary panic frequently reported upon by the media.

Thousands of species of American plants have depended upon insect pollinators for millions of years–ever since the evolution of flowering plants. The fossil record of these insects is scant.  When rare circumstances do occur that preserve ancient insects, the remains are usually so fragmentary they can’t be identified at the species or genera level.  Some nests of a species of leafcutter bee (M. gentillis) were found in the La Brea tar pits, California.  The same species still lives in the region today.  Studies of Pleistocene insects determined individual species adjusted their range according to fluctuating climate cycles, but no known large scale extinctions occurred during this era. (See: https://markgelbart.wordpress.com/2012/07/18/using-fossil-beetle-assemblages-to-determine-temperature-ranges-during-the-late-Pleistocene/) The insect pollinators we find in our yards today are the same species that lived during the Pleistocene.

Reference:

Bjerga, Alan

“Betting on Nature to Solve the Bee Crisis”

Bloomberg Business Week May 18-24, 2015

Blue Crabs (Callinectes sapidus) in Freshwater Springs

April 14, 2015

Marjorie Rawlings owned an orange grove in north central Florida from 1928-1941.  She was not a native southerner but used inheritance money to purchase the property.  Many of the characters she created in her short stories and novels were based on the people she met while she lived here.  Her most famous work is The Yearling, a novel later adapted for the big screen.  I think her most interesting book is her memoir of the 13 years she lived in a farm house next to her orange grove.  The title of this memoir is Cross Creek.  The relationships she developed with the “colored help” and the white “crackers” are entertaining reading.  Though progressive for her time, she clearly viewed black people as 2nd class citizens.  On 1 occasion she spent a week long hunting trip with her visiting brother.  When she returned to the farm she was outraged to discover the live-in “colored” help had spent the week enjoying a drunken orgy (literally…2 men and 1 woman in the same bed) and not a single chore had been completed.  Her brother joined her in chasing the help off the property at the point of a shotgun.  In my opinion Rawlings was at fault for being out hunting instead of supervising.  Moreover, today, her actions would be considered an illegal eviction, and she and her brother could be jailed for making terroristic threats.  However, if I could journey to 1930s Florida in a time machine and suggest this, all the white people there would think I was out of my mind.  How times have changed.

Marjorie Kinnan Rawlings with her dog - Cross Creek, Florida

Marjorie Rawlings, author of the famous novel–The Yearling.  This dog was accidentally poisoned.  She accused her neighbor of deliberately poisoning her dog, a charge he vehemently denied.  They feuded for a year before reconciling.

My favorite chapter in Cross Creek chronicled the local cuisine.  Bread here meant cornbread, cornpone, hoecakes, hushpuppies, or biscuits.  Meat meant salt pork, known here as “white bacon.”  Pork in 1930s America was much fattier than modern day pork.  White bacon was soaked in water, floured and fried.  The grease rendered from frying the fatty pork was used to season biscuits, cornpone, sweet potatoes, black-eyed peas, green beans, and greens.  These were the staple dishes but hunting and fishing supplemented the local diet with many exotic sources of protein such as alligator, rattlesnake, turtles and their eggs, limpkin, blackbirds, bear, and squirrel.  Rawlings accompanied men who went crabbing at night.  They caught crabs from a freshwater spring that flowed into the St. John’s River.  The men stood on boats and located crabs by shining lights into the clear water.  They used 12 foot poles with iron jaws on the end to snatch the crabs.

Crab

Blue Crab in Crystal River Spring, Florida. It’s probably a male.  The females stay in brackish water and migrate to waters with high salinity to release their eggs.

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Blue crab life cycle.

I was surprised to learn that blue crabs inhabit freshwater.  Apparently, during spring male blue crabs migrate in enormous numbers to brackish and fresh water.  During mating season the 2 sexes meet in brackish water to mate, and the females carry their fertilized eggs back to the saltier depths.  The larval stage of the blue crab is known as a zoeal.  As the zoeal grows, they shed their shells 7 times in a process known as molting.  Their bodies absorb calcium from the sea water and swell, and this extra calcium forms a hard exoskeleton.  Blue crabs are called megalops during the next stage of their life when  they move into water with lower salinity where they eventually transform into adult crabs.

Blue crabs outcompete and drive away crayfish in the freshwater springs they inhabit.  Both species eat the same foods, scavenging and actively hunting plant and animal material.  Blue crab larva can’t survive in freshwater.  If this species ever evolved that ability, they would eventually colonize freshwater creeks and rivers, causing a decline in crayfish abundance and diversity.  Fossil remains of the Callinectes genus date to about 15 million years ago, and Pleistocene-aged blue crab shells have been found from Massachusetts to the Caribbean and Texas.  It is an incredibly successful species.

Giant Leopard Moths and Red Wasps are Invading my Property

August 19, 2014

In some ways insects are more adaptable than large mammals.  Insects are capable of evolving in response to environmental change much more rapidly than large mammals because several generations can reproduce within the timespan of just 1 growing season, while some large mammals take decades to produce a single generation.  The presence of humans has obliterated 70% of North America’s large mammal species, but it hasn’t put a dent in insect populations.  I will never see a mammoth or saber-tooth in my backyard.  However, thousands of interesting species of insects invade my property, and they are active almost year round, though the coldest days of winter relegate most of them to dormancy.  Most of the insects I find on my property are likely the same species that inhabited this space during the Pleistocene.  Insects suffered few known extinctions at the end of the Ice Age but instead experienced shifts in range distributions. (See: https://markgelbart.wordpress.com/2012/07/18/using-fossil-beetle-assemblages-to-determine-temperature-ranges-during-the-late-pleistocene/).  Climate in my neighborhood (Augusta, Georgia) remained relatively stable during this transition, and the change in insect species composition has probably been minimal since then. Recently, I’ve encountered 2 species of insects that have occupied my homestead space for hundreds of thousands of years.  Maybe, I should change the title of this essay, and call it “humans invading moth and wasp territory.”

Giant Leopard Moth, Ecpantheria scribonia

 

 

 

 

 

 

 

 

 

Giant Leopard Moth (Hypercompe scribonia)

This woolly bear caterpillar is the larval stage of the giant leopard moth.

The giant leopard moth (Hypercompe scribonia) is a large species with a wingspan of nearly 3 inches.  It has beautiful teardrop-shaped spots on its wings.  That is the description I googled to help me identify this species.  I found a dead specimen near my wildflower bed but didn’t take a photo. (I ripped off the above photos from google images.) It probably died after depositing fertilized eggs on 1 of the species of flowers growing in my garden.  Their larva are known as woolly bears (as are the larva of many other species of moths), and they feed on a wide variety of plants including but not restricted to violets, mustards, basil, trumpet vines, sunflowers, mulberry, magnolia, and locust.

 photo Daphnesdorm001_zps3665f00a.jpg

Red paper wasps (Polistes sp.) nesting between my screen door and side door.  It’s a door we never use, so I let them stay there.  Though manmade, it mimics a hollow tree stump or log in scarce supply in modern young forests.

A nest of red paper wasps (Polistes sp.) lives in the space between my side door and screened-in door.  There’s a hole in the screen, allowing access to this sheltered area.  Before humans built structures, paper wasps built their nests in hollow tree trunks, but there are few den trees in the young 2nd growth forests surrounding modern day suburbia.  I’m letting the wasps live in the doorway because: a) we never use the side door, b) they are not aggressive, unless defending their nest, and c) they are beneficial predators, destroying the kinds of caterpillars that like to eat their way through my garden.  Each cell of the wasp’s nest contains a wasp larva with a paralyzed caterpillar upon which it feeds.

There are 28 species of wasps in the Polistes genus that live in the southeast, and I’m not enough of an expert to identify the exact species to which my housemates belong.  I admire these little monsters–they invented paper millions of years before the 1st humans evolved.

 

 

 

Deadly Digger Wasps

August 30, 2013

Last January, plumbers installed a new drainfield for my septic tank, reducing my wealth by about $5,000.  The alternative was a monthly $200 bill to pump out a tank that had become clogged with biofilm which is just a fancy word for shit turned into mud and root masses.  They had to dig up a significant wedge of my backyard, felling a productive fig tree in the process.    They covered the new pipes with bare dirt, and I transplanted a few peach tree saplings in the empty space.  I don’t care for well manicured lawns–the boring landscape choice of most of today’s fascistic conformists. So I didn’t plant any grass.  Instead, I looked forward to seeing what plants existed in the natural seedbank, though I did plant a few rows of oats and fieldpeas and scattered a container of wild flower seeds in 1 patch.  Now, there is a nice carpet of crabgrass, nutsedge, and wild sorrel growing underneath the pokeweed (aka pigeonberry) and nightshade I choose to let stand when I swing the scythe I use to keep my yard from looking so unkempt that I get yet another city code violation.  There are still patches of hard packed sand in this miniature wilderness, and these bare spaces attract female digger wasps.

Cerceris bicornuta , the weevil wasp, digs a chamber into hard packed sand where it lays its eggs.  It then goes hunting for weevils.  It subdues the weevils with paralyzing stings and deposits them next to its eggs.  The paralyzed weevils stay alive and fresh and become food for the wasp larva when they advance past the egg stage.  I found a weevil wasp in my yard, and one evening I placed a glass jar over its chamber entrance in the hopes that I’d get a good look at it, but alas it had evidentally abandoned the nest.  Nevertheless, the below photo is a much better image than I could have gotten with my cheap camera.

Female Cerceris bicornuta on Virginia Mountain Mint

Adult weevil wasps get energy from the sugar in flower nectar, but they have an all protein diet in their larval stage.

The weevil wasp belongs to the Crabronidae family which includes 200 genera and over 9000 species.  Most of the species in this family dig chambers into the ground, though some build nests elevated above ground.  Most wasps in the Cerceris genus are specialized predators of weevils.  The Astata genus includes predators of stinkbugs, the Zyzzyx genus includes predators of flies and butterflies, the Sphecus genus are known as cicada killers, the Pison genus are murderers of spiders, the Microstigrinus genus are social wasps  preying on everything from flies to caterpillars, and the Philanthus genus slaughters bees.  Digger wasps are deadly to whatever prey they specialize in feeding to their larva, but not to humans, unless a particular individual suffers from the type of allergy that causes an extreme auto-immune response.

Today, diggers wasps benefit from human construction activities that create bare patches of hardpacked sand such as dirt road sides or cleared land where they can dig their nesting chambers.  During the Pleistocene, digger wasps likely benefited from the presence of large congregating herds of megafauna that trampled and denuded vegetation, creating the ideal bare surfaces they require to nest.  Digger wasps have existed for at least 300 million years and shared planet earth with the dinosaurs.  But most people view diggers wasps as minor annoyances with the potential to sting.  Wasps do not exist simply to sting people.  They play a central role in controlling populations of insects that may actually compete with humans for survival, as any gardener or farmer plagued with stinkbugs, flies, and aphids can understand.  They deserve our respect for they will probably still be digging nesting chambers in bare patches of earth long after Homo sapiens suffers extinction.

Using Fossil Beetle Assemblages to Determine Temperature Ranges During the Late Pleistocene

July 18, 2012

Man’s scientific investigation of the natural world will always remain incomplete.  The amount of potential knowledge seems infinite while the number of scientists available for study will always be quite finite.  Some topics have never even been explored or they’ve barely been studied.  So if a single scientist takes a sincere lifelong interest in one obscure topic, they can make a big difference in the state of mankind’s knowledge of at least that singular subject.  Dr. S.A. Elias is an example of a difference-maker.  He took an interest in Pleistocene-age fossil beetle assemblages, and how ancient climate could be reconstructed based on species composition.  Without just this one scientist, we would know next to nothing about this obscure but fascinating topic.

Dung beetle moving a beagle turd.  Photo from www.nativeplantwildlifegarden.com There must have been a lot of dung beetles  pushing megafauna dung around in the Pleistocene environment.

Past climates can be derived by comparing the current mutual range of extant beetle species with that of fossil beetle assemblages found in various Pleistocene-age sites across North America and Eurasia.  This is known as mutual climate range reconstruction or MCR.  Species of beetles have specific maximum temperatures in summer (TMAX) and minumum temperatures in winter (TMIN) within which they or their eggs and larva can survive.  So by cataloguing the species of beetles and their present day temperature requirements, scientists can determined the approximate maximum and mininum temperatures that occurred at a certain site during the time of deposition.  And they can determine what type of environment prevailed because most species of beetles are associated with specific habitat types.  The geographical ranges of different species of beetles have shifted over time in correlation with climate change.  Surprisingly, the geographical ranges of slow moving flightless beetles and even cave beetles have also shifted in correlation with climate change. Very few, if any, Pleistocene beetle species, became extinct at the end of that era.  They survived changes in climate by shifting their geographical ranges.

Chart from one of the below referenced studies comparing modern day average annual maximum temperatures in Alaska and the Yukon with those from different periods during the last Ice Age based on data from beetle species composition.  Not included on this chart is information about the Sangamonian interglacial in Alaska.  TMAX temperatures during the last interglacial were 5 degrees F warmer than those of today.  Paradoxically, TMIN temperatures in January were slightly warmer than those of today during the Last Glacial Maximum when TMAX temperatures during the summer were as much as 10 degrees F cooler.  This indicates less seasonality then.

Pleistocene beetle fossils have mostly been found in 3  regions of North America.  In the midwest and east they’re found in bogs.  In the west they’re found in ancient packrat middens.  And in Alaska they’re found in permafrost.

In the east and midwest, Pleistocene-age beetle fossils have been found in Canada, New York, Pennsylvania, Michigan, Minnesota, Wisconsin, Illinois, Missouri, and Iowa.  Six beetle assemblages excavated from a site in Titusville, Pennsylvania date to between 48,000 BP-43,000 BP.  Interstadial conditions occurred here ~47,500 BP with average annual temperature maximums only about 3.5 degrees F cooler than those of today (I converted the celsius temperatures in the scientific study to Fahrenheit).  However, the fossil beetle assemblages suggest average annual minimum temperatures were almost 11 degrees F cooler than those of today.  By~43,200 BP temperatures here cooled even more drastically.  Fossil beetle assemblages at a site in St. Charles Iowa also indicate decisive environmental change.  ~38,500 BP, a prairie/savannah environment prevailed here with some mixed conifer/hardwood forests, but by 32,900 BP  a cool spruce forest predominated.  Boreal and arctic species of beetles lived in the midwest during the Last Glacial Maximum beginning ~30,000 BP.

Beetle species compositions from ancient packrat middens (packrats collect shiny objects including beetle exoskeletons) in Texas, Colorado, New Mexico, Utah, Montana, North Dakota, and California indicate alternating wet and dry climate phases.  Paradoxically, during stadials when the rest of the continent endured cold dry conditions, the southwestern region of the continent was wet with lush vegetative growth and many lakes.  As recently as 13,500 BP, the Great Basin in Utah, today a hot dry desert, hosted a composition of beetles presently found in the Pacific northwest.

Permafrost in Alaska preserves beetle fossils from as old as 150,000 years ago.  Evidence from changing beetle compositions here demonstrate alternating cycles of dry steppe grassland and wet tundra.  During the grassland phase, ground beetles from the genuses Amara and Harpalus, pill beetles, dung beetles, and sagebrush weevils compose the assemblage, while during the wet tundra phase ground beetles from the Cryobius and Pterostichus genuses, rove beetles, and dwarf birch weevils dominate.  The Cordilleran Glacier expanded south of Alaska during the Ice Age.  This ice sheet locked up atmospheric moisture, creating a frigid grassland environment with little snow here.  During interstadials and interglacials, more snow and rain fall on Alaska, fostering growth of spruce forests and wet bogs.

Sagebrush weevil.  Fossils of this species indicate a dry grassy sagebrush environment.  There is little sagebrush in Alaska today, but it was a dominant component during stadial phases of the Ice Age.

Ground beetle from the Harpalus genus.  This genus of beetles predominated in Alaska during stadials when dry steppe grasslands were widespread in this region.

The La Brea Tar Pits in California also trapped beetles.  Many of the species found at this fossil site are the same as those found in the area today, but there is a slight difference.  The types of beetles are more representative of those found in San Francisco rather than present day Los Angeles, indicating slightly cooler climatic conditions.  The only beetle fossil site in the southeast that I could find in the literature is Vero Beach, Florida.  The fossil beetles found here are the exact same as those found at the present time.  Other localities in the south probably would show changing compositions of beetles, but perhaps to a lesser degree than those from other parts of the continent because the Atlantic Ocean had a moderating effect on climate in this region.  Currently, there isnt’ enough data here to know for sure.

References:

Elias, Scott A.

“Mutual Climate Range Reconstruction of Seasonal Temperatures Based on Late Pleistocene Fossil Beetle Assemblages in Arctic Beringia”

Quaternary Science Review 20 (1) Jan 2001

Elias, Scott A.

Encyclopedia of Quaternary Science

Elsevier Science Publisher 2007

Blueberry and Bumblebee

May 21, 2012

I have 4 cultivated blueberry bushes.  They usually flower in March, produce fruit in June, and offer lovely red foilage in  fall.  This year, winter ended 2 weeks earlier than normal, and Saturday (May 19th) I harvested my first blueberries.  They were plump from a recent drought-breaking rain.  I made my first batch of blueberry pancakes the following morning.  My bushes give me all the berries I need for pancakes, muffins, and desserts for about a month.

My blueberry bushes flower in February and March.  The bees swarm to them every year.  Without these pollinators there would be no fruit.

Note the bees.  The most common species pollinating the flowers are the southeastern blueberry bees and bumblebees.  The former looks similar to the latter but is smaller.

Two bushes.  Two varieties.  One of the four bushes (not pictured) is stunted and doesn’t produce much yet.

Good plump berries by May 18th.

Blueberry flowers attract several kinds of bees well adapted to late winter/early spring weather conditions.  Because these species of bees are covered with hair, they are able to withstand colder temperatures than most other insects and are among the first arthropods to emerge in early spring.  The black coloring also helps increase their body heat.  The southeastern blueberry bees, bumblebees, and honeybees pollinate over 96% of the blueberry crop in southeastern North America.  The southeastern blueberry bee (Hapropodia laboriosa) is by far the most common type pollinating my bushes.  They look like a small bumblebee and are a solitary species.  The female digs a long burrow in sandy soil and broods her nest in it.  Their lifespan matches the length of time blueberry bushes flower–about 3 weeks.  They are completely dependent upon blueberry bushes, unlike bumblebees (Bombus sp.) which pollinate a much greater variety of plants.  Bumblebees live in colonies of from 200-2000 individuals.  They also nest in burrows where the overwintering queen becomes the sole survivor when hard weather hits.  Both of these native bees are not aggressive.  I’ve never been stung by either one.  One would have to roughly handle one of these species or invade a nest to get stung.

Horticulturalists cultivated high bush blueberries, creating hundreds of varieties, but low bush blueberries only grow in the wild.  Nevertheless, there are such extensive stands of low bush blueberries in Maine that they’re gathered wild and can be found in the frozen food section of many supermarkets.  Low bush blueberries grow wild in my neighborhood, including my front yard.  These ripen in late July/early August but are of disappointing quality compared to my cultivated high bush blueberries.  Euell Gibbons claimed wild blueberries work better in muffins than cultivated ones, but the variety that grows in my neck of the woods is hard and bittersweet.  My wife and daughter love cultivated berries but declined to eat the wild ones after trying them.  Eight species of blueberries are native to the piedmont region of the southeast: sparkleberry (Vaccinium arboreum), black high bush blueberry (V. atroccum), high bush blueberry (V. corynborum), Elliott’s blueberry (V. elliotti), southern low blueberry (V. pallidum), deerberry (V. stamineum), slender blueberry (V. tenellum), and early low blueberry (V. vaccillum).

Blueberries generally grow in colonies and prefer sandy acidic soil.  They thrive in sunny open areas with little to no tree canopy.  They can tolerate a few pine trees which don’t shade them.  They’re another fire adapted plant–underground runners help them resprout following ground fires.  When Euell Gibbons went hunting for blueberries, he’d visit the office of a National Forest ranger and ask him to point out on a map where the most recent burns had taken place.  Native Americans set fire to the woods nearly every year to foster habitat for berries, though this was done for several other reasons as well such as improving habitat for game, eliminating insect and snake refuges, and increasing visibility to avoid being ambushed by other Indians.

Undoubtedly, blueberries were a common component of southern Pleistocene landscapes.  Dynamic factors–sudden climate changes, unchecked wild fires, and megafauna foraging–created highly diverse environments including the open spaces blueberries require.  Pleistocene-aged heath pollen in measurable amounts occurred in Nodoroc, a mud volcano near Winder, Georgia (the central part of the state).  The pollen dated to ~30,000 BP, a brief interstadial immediately preceding the Last Glacial Maximum.  The pollen record here suggests an environment dominated by pine, oak, and grass; though hickory, spruce, and fir were common, while maple, beech, chestnut, and birch were present in this diverse landscape. The presence of high amounts of ragweed, an early successional species, is evidence of an environment in constant flux.  Pine pollen and macrofossils at Nodoroc suggest a mixture of southern species (shortleaf) and northern species (jack, red, and white).  In Maine wild blueberries grow in large barrens and are associated with the northern species of pine mentioned above.  One caveat–the heath family also includes common non-blueberry species such as azalea, mountain laurel, and fetterbush, so it’s likely they contributed to the heath pollen.  Scientists can’t differentiate to the species level when examining heath family pollen.

Pleistocene environments in Georgia may have included vast blueberry barrens such as those occurring in Maine today, especially with large flocks of passenger pigeons spreading the seeds that eventually found ideal habitat.  William Bartram rode his horse through miles of what he referred to as “strawberry plains” in north Georgia and North Carolina.  This environment–common just 200 years ago–is now completely extinct. Strawberries require sunny conditions, just like blueberries.  In the extensive wilderness of the Pleistocene perhaps blueberry barrens and strawberry plains covered miles of territory.

Maine blueberry barren.  This photo must have been taken during fall when the leaves turn red.  The owners of this land burn it often to faciliate the growth of wild blueberries–an uncultivated cash crop. Did Pleistocene Georgia have extensive blueberry barrens such as this?  Or did they just grow in small colonies wherever a fire burned a small section of forest?