Tuesday, September 28, 2010

Goldenrod Gall

Goldenrod Gall click to enlarge
While spraying Sericea lespedeza on La Petite Gemme Prairie outside of Bolivar, we noticed a profusion of round green knobs in the middle of the long goldenrod stalks.  The plants seemed otherwise healthy.  This was a phenomenon crying out for a Google search.

Goldenrod gall fly
The Goldenrod Gall is caused, logically enough, by the Goldenrod Gall Fly, Eurosta solidaginis.  These tiny flies, a fifth of an inch long, essentially live and die on goldenrod.  They are weak fliers, preferring to walk up and down the stem. When the male spots a female he gives her his version of a sexy wiggle and if she likes it, they mate.  She then goes off to inject her eggs into the stem of a goldenrod.
The fly is completely dependent on goldenrod, its only host plant.  Once the larvae hatch they eat the inside of the stem, their saliva stimulating the plant to produce the tough gall covering.  The larva will dig an escape tunnel for future use and produce a type of antifreeze to survive the winter.  In the spring the larva pupates and the adult emerges from its prefab tunnel.
Eurytoma wasp Bucknell.edu

Now it starts to get interesting.  There are two species of parasitic wasp (Eurytoma) whose larva can only survive by eating Goldenrod Gall Fly larva!  The wasp insert their eggs into the gall and their larva then seek out the fly larva.  
There is another gall forming insect with its own obligate larval predators.  The Goldenrod Gall moth, Epiblema scudderiana, lives inside the hollow stem and creates a more subtle gall.  It has larval predators that have not been identified.

This obligate interdependence occurs throughout the natural world.  Loss of one species leads to extinction of many others that can't survive without it.  Many people would like to see goldenrod disappear because they falsely blame if for their allergies.*  If this were to occur, we would lose at least five insect species.

* Goldenrod is innocent of all charges in creating allergies- its pollen is only carried by insects.  It blooms at the same time as its neighbor ragweed, whose tiny airborne pollen particles cause our allergies.
The whole story of these insect's life cycles with photographs can be found at this site.

Friday, September 24, 2010

Ants and Elephants

Just what makes that little ol' ant
Think he'll move that rubber tree plant
Anyone knows an ant can't
Move a rubber tree plant 

I know it is a long way from the Ozarks, but this story was too good to pass up.  The New York Times reports that an African ant which lives on the sweet sap of a variety of Acacia tree attacks elephants that would otherwise eat the tree, successfully defending their home and way of life.
"The tree, known as the Acacia drepanolobium, is a generous home to ants that live in its bulbous swellings and feed on a sugary solution it produces. In return, the ants serve as guardians, instantly attacking any creature that approaches the tree. In the case of elephants, ants crawl up the inside of their trunks and agitate sensitive nerve endings.
“An elephant’s trunk is a truly remarkable organ, but also appears to be their Achilles’ heel when it comes to squaring off with an angry ant colony,” said Todd M. Palmer, a biologist at the University of Florida and the paper’s co-author."
When fed the same tree without ants, the elephants ate them readily.  They are apparently able to smell the presence of the ants and avoid them.  This protective behavior may be important in the ecosystem, as fire moves more readily through grasslands unprotected by trees.  The whole story including a fascinating video can be seen at Current Biology.

Monday, September 20, 2010

Soldiers on the Flowers

Pennsylvania Leatherwing
There are soldier beetles flying all over, from Bull Creek to our backyard.  They are landing on clothing, cars and lawn furniture but especially on their favorite plants.  They are Pennsylvania Leatherwing (Chauliognathus pensylvanicus), a species which feeds on the nectar of Goldenrod and Thoroughwart (Eupatorium) that bloom from August through October.  They seem to have adapted to the exotics in our backyard such as celosia.
Their larva live on the ground under leaf litter, stones, logs, etc.  They are predatory, eating insect eggs and larva.  Adults and larva both have abdominal glands which secrete defensive chemicals.*
Adapting to city life on Celosia
These beetles are strong fliers and locate their host plants with uncanny accuracy.            
They are valuable as pollinators and are said to eat aphids and even cucumber beetles.  If this is true, I wish they would get busy as we have a massive attack of cucumber beetles, seemingly misnamed as they also eat kale, spinach, beans, squash, and everything else they can land on. 
Five-spotted Cucumber Beetle

For those of you who are careful readers, you may have picked up on the pensylvanicus with only one "n".  This isn't one of my frequent mistakes.  Bugguide says "The spelling with one "n" was in common use at the time (de Geer says in the description that the specimen was sent to him from "Pensylvanie"), so the species name based on it can't be corrected under the rules governing scientific names."[Bugguide.com]

*Field Guide to Insects of North America- Kaufman

Thursday, September 16, 2010

Pollination Problems

from Science Daily
The decline in bee populations, the so called "colony collapse", isn't news.  What is news is that there is a decline in some flower pollination occurring separate from the number of bees.
Science Daily reports that localized changes in climate is a major factor.
"Bee numbers may have declined at our research site, but we suspect that a climate-driven mismatch between the times when flowers open and when bees emerge from hibernation is a more important factor," says James Thomson, a scientist with U of T's Department of Ecology and Evolutionary Biology."
"Early in the year, when bumble bee queens are still hibernating, the fruiting rates are especially low," he says. "This is sobering because it suggests that pollination is vulnerable even in a relatively pristine environment that is free of pesticides and human disturbance but still subject to climate change."
This has potential to occur an any climate where there are changes progressive changes in temperature patterns.  With  increased warming, temperature increases also start to occur earlier in the year.  This can affect not only the availability of seasonal pollinators, but also the animals which depend on the plants for nutrition.
Obviously, these changes have occurred throughout the life of the planet.  This is just one factor in extinctions as well as the adaptations that new species make with time.  Much as we would like to keep the planet, or at least our neighborhood, just as it "always was", time marches on.  We just need to be sure that we aren't causing it to march too fast.

Sunday, September 12, 2010

Cockroach Antibiotic

Drug-resistant bacterial infections have become a major problem of the current decade.  Increasingly powerful antibiotics are frequently variants of current drugs and bacteria can develop resistance to them within a few years.  So where do you look for a completely new antibiotic to attack them?  Why not try a cockroach brain?

LiveScience.com reports that researchers have found at least 9 compounds in the brain and nervous system of cockroaches and locusts which fight drug resistant strains of E. coli and Staphylococcus aureus.  Since cockroaches can carry over two dozen human pathogens, it was logical to look at why they weren't susceptible to them.  The article doesn't discuss how you dissect out a cockroach brain.  I would guess that first you hire this really tiny little neurosurgeon.
Why a cockroach?  Well for one thing, they are about the oldest creature that you can see moving with the naked eye. Fossils of cockroach-like creatures date between 354–295 million years ago and the species has survived and evolved through the last three mass extinctions.  The modern cockroach has existed since at least the early Cretaceous Period which wiped out the dinosaurs.
For a species to survive that long, you have to be one tough cookie.  You may recall the recent blog describing a woman stepping on a living cockroach and having a horsehair worm crawl out of it. Cockroaches live in areas where they are exposed to all the bacteria in animal waste and presumably have developed their own resistance to them.
For such an antique animal, their behavior can be relatively sophisticated.  They can leave a pheromone trail which other cockroaches can follow to food sources or swarming for shelter and mating  They also can teach us humans something about developing group dynamics, as described in Wikipedia.
"Research has shown that group-based decision-making is responsible for complex behavior such as resource allocation. In a study where 50 cockroaches were placed in a dish with three shelters with a capacity for 40 insects in each, the insects arranged themselves in two shelters with 25 insects in each, leaving the third shelter empty. When the capacity of the shelters was increased to more than 50 insects per shelter, all of the cockroaches arranged themselves in one shelter. Researchers found a balance between cooperation and competition exists in group decision-making behavior found in cockroaches. The models used in this research can also explain the group dynamics of other insects and animals."
It is said that cockroaches will inherit the earth long after humans are extinct.  Like many other insects, they can withstand ten times the dose of radiation which is lethal to humans.  Radiation is lethal to cells when they divide.  Unlike mammals whose cells are constantly dividing, a cockroach's cells divide all at once during their molting period.  A blast of radiation will kill some but doesn't affect the others who are between molts.
So, will cockroaches inherit the planet?  Well, they have a good chance.  They can live in a wide variety of climates, survive underwater for half an hour, remain active for a month without food and "survive on limited resources like the glue from the back of postage stamps."    They may run short of food as we convert to e-mail, but they probably won't get Staphylococcal meningitis.

Friday, September 10, 2010

Frost Flower's Science

Early Frost Flower on stem
Frost flowers are winter ephemerals, meaning that the “blossoms” usually are gone a short while after the sun hits them or the temperatures rise above freezing.  They “blossom” with the first night of hard freezing temperatures and tend to recur with subsequent freezing nights after warming days. 

There are a few native plants which can be counted on to grow frost flowers.  Freezing temperatures forces water out through splits in the stem’s epidermis, creating ribbons of ice so thin that you can see your finger print through them.  The stems remain intact as the ice may extend several feet up the stem at the first “flowering.” Subsequent ribbons tend to form around the base of the stem, frequently creating thicker spirals.

First bloom- 3 foot tall
This ribbons of ice
The two common species of plants producing frost flowers in our area are White Crownbeard, Verbesina virginica, Yellow Ironweed, Verbesina alternifolia, both of which are also called Frostweed.  These are commonly found in southern Missouri seen in large numbers on roadsides, the edges of fields, thickets and woods.

Late blossom at stalk base
Ice Ribbons
Two other species are known to produce smaller frost flowers, Dittany, Cunila origanoides and Frostweed, Helianthemum canadense.  There are single incidental reports of other plants producing these icy ribbons. 

This is an area which is ripe for citizen science.  Since finding frost flowers requires getting out early on frosty mornings, many other species may be producing small frost flowers that go unnoticed.  I would challenge you to watch the weather next fall for the first frost and wander your garden and woods.  If you are a gardener, look carefully around to see if any of your plants have basal ice ribbons.  If you can find them on other plants, photograph them, identify the plant if possible and send them to me at rekipfer@gmail.com.

More detailed science is available these sites:
- biosci.utexas.edu 
- http://my.ilstu.edu, /~jrcarter/ice/diurnal/

Thursday, September 9, 2010

The Sixth Extinction?

The threatened extinction of any species is newsworthy now in the age of communication.  Try as we might to preserve species, extinction is a natural phenomena, occurring daily.  There have been at least five Mass Extinctions in the geological record.  What is more disturbing news is that the rate of extinctions appears to be speeding up and we are partially to blame.
The role of human activity in extinction is well known.  The Galapagos Islands served as an isolated laboratory where we could see whalers on the past centuries hauling giant sea turtles on board as a stored food source until the species was a "dead as a dodo".  Even that expression recalls the famous flightless bird's disappearance for Mauritius, last seen in 1662.  The Dutch sailors found the meat a little tougher that pigeons, but much more accessible as the bird didn't fly and wasn't afraid of humans.
The disappearance of megafauna such as woolly mammoths from North America during the Pleistocene Extinction, occurred at the time of the arrival of hunting bipeds with meat on their minds.  This has been dated as between 13.8 and 11.4 thousand years ago according to an article in Science Daily.  There was also a dramatic change in climate and possibly a comet impact that could have produced dramatic climate changes for a few years.  Did humans have a hand in it?  Maybe.
As extinctions go, the North American megafauna was no big deal.  Occuring over a short period of a few hundred years, it was the equivalent of a nanosecond in our earth's history but critically important to a species like ours which has only been keeping records for a few thousand years.
Mass extinctions have occurred five times in our geological history.  These may occur over thousands of years, and wipe out 50-90% of the species on the planet.  They give a chance for new species to develop at the cost of the loss of more familiar species.
Are we entering the Sixth Mass Extinction?  Many environmental scientists think so.  Studies reported in Live Science have concluded that although the rate of natural extinction has increased, it is impossible to predict how many species will react.
One thing is for sure.  We are impacting the environment, not just from pollution, carbon dioxide increases and their debatable effect on global warming.  As acidification dissolves the reefs, we are affecting the bottom of the food chain.  As the top predator, this should be a matter of concern.

Saturday, September 4, 2010

Learned Behavior

Several recent stories have highlighted animal's ability to learn, whether spontaneous or by training from humans.

Dolphin Bubbles
Click to enlarge
This Wimp.com video from Seaworld demonstrates a parlor trick that a few dolphins have learned and apparently passed on to some others who have watched and learned.  These animals have been under observation for years and yet this bubble blowing has been seen only recently. 
They not only can repeatedly blow bubble rings but have learned to play with them.  They interact with other dolphin's bubble, at times breaking it up before another dolphin uses it.  Amazing!

Bonobo Language
Kanzi- from Time.com
Time magazine had a feature on Inside the Minds of Animals.  Among other studies, it describes the language and communication of a bonobo named Kanzi who was trained at the Great Ape Trust in Des Moines, Iowa.  Not only is he capable of following language symbols, but he can transmit his own spontaneous wishes such as asking for a cup of coffee.
Kanzi can understand and use compounded symbols to express ideas and even communicate time differences, describing kale which was tough and hard to chew as "slow lettuce".  He asks for pizza by combining the symbols for bread, cheese and tomato, demonstrating also his acquired gourmet tastes.
If you can't find the magazine, I think you will enjoy the outtakes above and this video.

Thursday, September 2, 2010

Tiger Swallowtail

Caterpillar- Matt Boehner
A while back, Matt Boehner sent me a picture of a larva his dog had coughed up.  It had a funny bluish tint (you would probably too if you had been coughed up by a dog) but its markings were typical of an Eastern Tiger Swallowtail larva.  I used Photoshop to adjust the colors to that of the grass, getting it closer to a true color. 

 Early Instar- buglifecycle.com
Tiger Swallowtail larvae change dramatically in appearance as they develop.  The larvae go through four molts, called instars, before they reach full size and form their chrysalis.  The early instars look like "bird poop" while the final instar is bright green with "eye" spots.  See this page for examples.

Fourth Instar- Gardenweb.com
When a caterpillar is fully grown it wanders away from feeding on its host plant in search of a suitable pupation site.  It frequently darkens during this stage as seen by Matt.  This darkened brownish color is probably more protective as it leaves its green leaf perch to attach its chrysalis onto something more substantial like a gray twig or bark.

Eastern Tiger Swallowtail
Color is in the brain of the beholder- who knows if one person’s blue is the same as another's?  Wavelength is real, so you can always count on a spectrum from sunlight for an objective check.  The problem is that you can’t rely on cameras and computer screens to reproduce it accurately, at least not without a lot of attention to detail.

The idea that we don't share the same descriptions of colors has led biologists to develop color comparison charts.   Robert Ridgway's color standards for bird identification might save my marriage.  Barb and I are always arguing over what is blue or green.  Perhaps you have a similar spousal story- if so, spare me as I have enough trouble correcting my wife.

For information and pictures go to this site.
Addendum:  Matt reports that it formed a chrysalis.  I was afraid after its dog-gone experience it would be "too pooped to pupate."