Thursday, July 2, 2015

Slowmo Swallowtails

Giant Swallowtail at the Butterfly House - Christ Barnhart
Sometimes you see something that doesn't need scientific explanation.  Chris Barnhart sent me this beautiful this slow-motion video of Giant Swallowtails nectaring.  Without technical details or jargon, it shows the ballet of wings that lets the butterfly probe each tiny blossom on the anise hyssop (Agastache foeniculum), moving over the plant with its legs only lightly touching it.

Chris filmed this with an I-Phone and I am frankly jealous.  You can see this kind of action daily at the Bill Roston Butterfly House at the Springfield Botanical Gardens.

Wednesday, July 1, 2015

A Mastication of Caterpillars

Milkweed Tussock Moth caterpillars - Chris Barnhart
We just had written on June 27th about the Milkweed Tussock Moth caterpillars, showing their gregarious tendencies, clumping together on a leaf to chow down.  There are lots of special names for groups of animals such as a "murder of crows."   The "official" name for the group of caterpillars is "an army of caterpillars."

Kevin Firth has proposed an ever better name, "a mastication of caterpillars."  If you look at this time-lapse video by Chris Barnhart of tussock moths devouring a milkweed leaf I think you will agree.

Monday, June 29, 2015

Goatbeard - Not a Dandelion

Tragopogon dubius - Changing beauty by focusing deeper
Ever since we first walked the fields of Bull Mills in spring, I have been intrigued with the Goat's Beard, a.k.a. Salsifly, Tragopogon dubiusIt resembles a dandelion on steroids but is so much more.  It can grow waist high and both the flower and the seed head are much larger than a dandelion, allowing you to see the intricate details without magnification.

The seed head first appears as a tightly wrapped green flame with the long strands packed inside.  As it opens as seen below, it briefly goes through a stage where ghostly circles appear deep inside, only to disappear once it is fully expanded.

Typical of a widespread species, this Goat's Beard has accumulated a number of regional names such as western salsify, western goat's-beard, wild oysterplant, yellow salsify, yellow goat's beard, goat's beard, goatsbeard, common salsify, and salsifyI say "this Goat's Beard" because of the other plants of the same common name such as Aruncus dioicus, Astilbe biternata and Tragopogon pratensis.  That is one reason botanists always use the fancy Latin names.

Tragopodon dubius
Dandelion - Wikimedia

Both the dandelion and T. dubius are exotic plants originating in Eurasia and transported here by humans. The fine line between exotic species and invasive species is complex.

Nature determines where it can exist or thrive (climate, soil, competing species, etc.) and society measures its relative value or harm and the economic cost of keeping it controlled.  Witness the spartan Missouri Noxious Plant list of 12 species and neighboring Illinois Invasive Plant List of 102 species.

One person's invasive can be another's favorite, as we see in the proliferation of Callery Pear species, a.k.a. Bradford Pear.  They line (and even name) our parkways and driveways in Springfield while being listed as invasive in Illinois.

"Take our dandelion- please!" with apologies to Henny Youngman.
The dandelion became a botanical pariah because of its invasion of our carefully manicured lawns, a socially desirable grass monoculture that is seemingly abhorred by nature which favors diversity.  American lawns seemingly evolved from an envy of the English manor house lawns that were maintained by a team of servants and the invention of the lawn mower which allowed the homeowner to play servant for several hours a week.  Dandelions can thrive and spread easily in this artificial monoculture.

Our T. dubius on the other hand has avoided urbanization and is modest in its spread in the wild.  This may be partially because of its height, making it vulnerable to the close cropping, zero-turn lawn mower, the more civilized cousin of my ATV.  It appears sparingly scattered in our warm season grass fields and deliberately neglected field edges where it is careful not to overwhelm its neighbors.  In this setting it provides an occasional splash of color while respecting its neighbors.

Ghostly circles appear early...
..... then seem to fade as it fully expands

T. dubius is a good nectar source for a variety of bees and flies but mammals avoid it because of its bitter milky sap.  As long as it continues to play well with neighboring plants, it will remain one of my favorites, even if they don't respect it in Illinois.

Saturday, June 27, 2015

Milkweed Tussock Moth

Milkweed Tussock cats - Kelly Bigbee
Kelly Bigbee of Fassnight Creek Farms is one of a number of volunteers at the Butterfly House who are raising butterfly larvae and host plants for the house.  Milkweed is grown for Monarch Butterfly larvae but last week she sent a picture of a plant seen on the right resembling a Lutheran potluck.*  It was covered with ravenous caterpillars of a different breed, the Milkweed Tiger or Tussock Moth, Euchaetes eglei.

In the photograph above, a Monarch caterpillar is hanging below the leaf with a Tussock Moth on top.  Chris Barnhart noted that the Tussock Moth seems to mimic the Monarch cat in both coloration and size when you account for the mass of hairs.

Since birds tend to avoid Monarchs because of the milkweed toxin in their bodies, could this be a case of Batesian mimicry, using its similar appearance to warn off predators by pretending to be a toxic Monarch cat?  Actually it is even more complicated.  The Milkweed Tussock Moth also stores the milkweed cardiac glycoside toxinsThis is an example of Müllerian mimicry, where two or more insects with the same toxic chemicals display similar color patterns to warn off predators.
Gregarious Tussock Moth caterpillars stripping a milkweed leaf - Chris Barnhart

These Tussock Moth caterpillars are gregarious, with multiple individuals feeding on the same leaf.  They can afford this exposure because if one of their siblings is eaten, the bird will soon be too busy upchucking to come back for seconds.

Milkweed Tussock Moth    Patrick Coin
Digitalis and Digoxin were cardiac glycoside drugs used in the past for congestive heart failure.  Nausea was a warning that the drug levels were too high.  Birds have the same reaction and I found proof in this series of photographs at Science Friday of a naive bluejay fed Monarch butterflies.

There is a lot of variation in the amount of toxicity in different milkweed species as well as individual plants.  The milkweed species in Monarchs' Mexico overwintering area is much less toxic.  Also predators vary in their sensitivity to the glycosides as well as their strategies for reducing their exposure.  This and other details are detailed in The World of Insects.

*Observation made by Barb's sister who is a connoisseur of Lutheran potluck suppers.

Thursday, June 25, 2015

Mosquito Laser

Feeding on a human - Wikimedia
The rain and high humidity the last two weeks has been a perfect storm for the mosquito population.  While they are a total annoyance and bites from each individual female carries the chance of disease, like everything in nature, they have a role in the food chain.

Male mosquitoes feed on nectar and may have a minor role in pollination.  Mosquito larvae consume bacteria and algae in the water and in turn provide a food source for frogs, fish, spiders and other species.  Dragonflies a.k.a. "mosquito hawks" and damselflies eat their share and their larvae eat lots of the mosquito larvae which hang just beneath the surface of the water, breathing air from little tubes in their abdomens.  Bats and birds such as purple martins eat their share, but none of these species would be significantly harmed if mosquitoes suddenly disappeared from earth.

Orange Damselfly eating mosquito -
Almost all the advertised options for killing them are nonspecific, attracting and killing not only mosquitoes and biting flies but also a variety of moths and other innocent insects.  This all leads up to a video a friend sent me of a TED talk demonstrating a high tech laser system that selectively spots mosquitoes and shoots them down in mid-air.  If only this could be perfected we might have the first video game that actually does something worthwhile!  Watch it at thisYoutube link.

 Elijah Hughes at this link has a good review of  the options.

Coming soon- What is it?

Sunday, June 21, 2015

Attack of the Hummingbirds

Long-billed hermit - Dennis Skogsbergh
On our recent birding trip to Honduras, Janice Reynolds told the story of an acquaintance who had heard that hummingbirds could kill a human by stabbing their beaks into the center of the throat.  This led to an ongoing string of jokes about wearing a neck scarf for protection, reaching a peak at the final stop where we sat amidst large numbers of hummers including the Long-billed Hermit.  While we mammals are safe, there is a tiny grain of truth in a hummingbird "going for the throat."

Hummingbirds are aggressive by nature and most are not very communal.  Males will attempt to drive away competition, whether at a feeder or in fights over females.  Most of these are aerial battles with bluffs and "chest bumps" but occasionally a few feathers fly.  Usually there is no serious damage except to their chances to mate with a particularly hot female.

If you recall that the largest hummingbird weighs less than a nickle (5 grams), it obviously hasn't enough mass to penetrate your skin, no matter how fast it flew into you.  Watching hummingbirds fight, they hover at close range, banging against their adversary.  Their beak is just for sucking nectar..... right?

Hermit - Robert Gallardo
According to recent research, the long-billed hermit hummingbirds that we saw in Honduras will "go for the throat" during mating season, using specialized beaks that have evolved for mating disputes.  Research led by Alejandro Rico-Guevara from the University of Connecticut showed that their elongated decurved beaks (curving downward) are the "the first evidence of weapons in male bills."

They had observed that unlike our ruby-throats who battle with close encounters and chest bumps, the hermit male hummingbirds used their beaks in territorial fights with rival males during mating season. Rico-Guevara and co-author
"Marcelo Araya-Salas, a Ph.D. candidate at New Mexico State University, measured the size and puncture capability of beak tips in juvenile and adult hummingbirds.  The researchers found that during the birds’ transition to adulthood – puberty, if you will – males developed elongated beak tips that were sharper than those of females.

They also observed male birds using their bills to stab one another in the throat during fights, and found that, not surprisingly, males with longer, pointier bills were more likely to win these battles and therefore defend the best territories."
Rico-Guevara has observed the use of beaks as weapons in other hummingbirds and plans more studies.  He "hopes people realize that despite their tininess, hummingbirds are strong and aggressive animals."

At Rio Santiago in Honduras we were surrounded by hummers, a total of 12 species in all at over 100 feeders, most only a few feet apart.  The air was filled with buzzing and diving but no direct confrontations because the number of feeders reduced the need to compete for one.  You too can reduce most of the hummingbird combat by putting up multiple feeders separated by several feet.

An article in Audubon magazine discusses this and other interesting bird behaviors in the name of "love."  Go to Love in the Air: Even in the bird world, romance can get messy.

Friday, June 19, 2015

Walk in the Park

Growing in furrows in the bark of a large willow tree
With the forecast of heavy rain and the threat of being flooded in by Bull Creek, we escaped early from Bull Mills and returned to Springfield to hike around the Springfield Botanical Gardens.  We were accompanied by Cole (7) and Paisley(5) who view the landscape from a lower level.  In addition to the beautiful gardens, we were looking for different views of nature, including the mystery finding above.

Spicebush Swallowtail caterpillar - Not an eye but don't tell a bird that.
We started at the Butterfly House where there were several species flying.  There were remnants of giant swallowtail eggs, partially eaten by their recent inhabitants.  This is usually the first meal of the newly hatched larva.  The Spicebush Swallowtail caterpillar is always a hit with its cartoon "face" decorated like a character from Disney Studios.

In the deep wood mulch around the flower beds we found little fairy gardens of fungi, sending up their little umbrellas in an effort to reproduce by sending out their spores, the seeds of the next generation They are easy to overlook from above but interesting to view
from ground level. 

Paisley, Cole and "Cecilia"
There were Red-eared Slider turtles basking in the middle of the lake and families of geese strolling the grounds.  This turtle caught Paisley's attention as it headed north from the lake.  Earlier this year turtles were out crossing the roads looking for love.  This time of year is the end of the courtship cycle and we wondered if it wasn't a female looking for a site to bury its eggs.

The most dramatic finding was on the bark of a willow tree on along the walk south of Lake Drummond (see top of page).  There were bright red growths in the furrows of a large willow tree on the upland side of the walk.  I initially guessed that these might be some sort of fungi but Patrick Byers came up with an even more interesting explanation - adventitious roots!

Walter Reeves refers to this finding as "water roots" which form in times of rainfall and high humidity.  They are apparently normal and harmless, disappearing in a few weeks.

The term adventitious in botany refers to structures that develop in an unusual places.  Willows can grow from shoots placed in soil.  The stems have primordial nodes which develop these adventitial roots, establishing the root system for the willow to grow. This is the basis of using willow cuttings stuck in the ground for riparian planting. CC
Why the pink to red coloration? Apparently nobody knows, although there are some interesting theories.  I couldn't even find much about them by an extensive Google search, but I did come across this beauty in England to confirm their presence.