Wednesday, September 29, 2010

Hummingbird Clearwing

Convergent evolution at its finest - the hummingbird clearwing moth (Hemaris thysbe) is definitely one of the coolest lepidopterans in the watershed.  I had the opportunity to photograph this individual a couple of years ago and it was amazing how much it resembled a hummingbird in its movements even in forward speed!  The clearwing is a member of the sphinx family of moths and is a close relative of the pandorus sphinx I highlighted a couple of weeks ago.

The hummingbird clearwing mimics its avian counterpart by
hovering from flower to flower imbibing nectar.  Hawthorn, wild
cherry and Japanese honeysuckle are good host plants for
clearwing caterpillar instars but the adults will visit a variety
of wildflowers including beebalm, thistles, lilac and in this case
spring rockets.

The distinct segmentation in the clearwing's thorax ensures it is not
an actual hummingbird.  This speicimen spans about 3 inches
from one wingtip to the other.  It's interesting how even the dark
green back mimics the ruby throated hummingbird male also native
to the Captina watershed. 

This moths wings beat an astounding 30-35 times per second and
it is always on the move making photography tricky.  Check out
the extended feeding tube probing the flower.  Adults usually
emerge from mid-June to mid-July in our area.  The next time you
see a hummingbird browsing through your flower garden take a closer
look and you may be surprised.


Wednesday, September 22, 2010

Downy Rattlesnake Orchid

When people think of orchids they often envision a brightly colored, oddly shaped flower in a tropical forest setting.  It is true that Orchids reside mostly in tropical ecosystems worldwide but there are 46 species native to Ohio and one in particular to the Captina watershed. 

The downy rattlesnake orchid Goodyera pubescens is easy to walk
past in the woods because of its small size.  Most rattlesnake orchids
only measure 2-3 inches across and lay nearly flat on the forest floor.
The orchid prefers rich wooded upland slopes usually under an oak/
hickory canopy although I have observed them under other hardwoods
as well.   Note the lattice work of viens throughout the leaves as a
good identifying characteristic of the plant.

After learning a little bit about the orchid's habitat it becomes easier
to spot them on the forest floor.  Rattlesnake orchids do not flower
every growing season like other native perennials with some individuals
going as long as five years between flowerings.  Factors that
determine flowering events are not clearly understood although they
could be weather or nutrient related.  So, you could imagine my
excitement when stumbling across this plant in the Pipe Creek
subwatershed since it is the only flowering rattlesnake orchid I have seen
in person.  The stalk is less than 18" tall so even at this time the plant is
small in comparison to other perennials on the forest floor.  Note how
dark the setting is even during a July afternoon indicating the thickness
of the over-lying canopy. 

Tuesday, September 21, 2010

USGS Topographic Maps

Good morning!  I am a huge fan of mapping so I get excited about any new technology that arises in this field.  The USGS has recently released a series of 7.5 minute quadrangles from it's online website that cover much of the US free of charge.  The downloads are in pdf format but are spotty for the upper Ohio Valley.  Most of the western half of the Captina Watershed area is covered though.  The only missing quadrangle is from the watershed is Businessburg which should be online soon. 

Click on the link below to go to the USGS store then select the Map Locator tab.  Next click on Show US Topo and Digital Maps, zoom in on the area of interest and follow the directions in the righthand box to download.  Enjoy!

USGS Topo Maps

Note: The files are somewhat large so download times may vary.

Friday, September 17, 2010

Caterpillars Continued...

Earlier this week I highlighted two of the more colorfully patterned caterpillars of the watershed.  The use of brightly colored patterns as a defense warning mechanism is widely documented in many animal species outside of caterpillars, however some species aren't as colorfully gifted and have to resort to other defenses to ward off predators.  The viceroy is one caterpillar that has taken camouflage to a whole new level.....

Why am I photographing bird poop you might ask? Because
if you watch this pile of excrement long enough it will begin to move.
Mutant bird droppings?  No, just an ingenious venture into defensive
camouflage by the viceroy caterpillar. The viceroy Limenitis archippus is
a member of the Brush-foot family of butterflies whose larvae are
known for their uncanny resemblance of bird droppings. Why would
 a caterpillar evolve to look like poop? It is the least likely thing for a
passing bird to investigate as potential food. Brilliant!

This viceroy was spotted munching on willow leaves, a preferred
host plant, on the creek bank.  Note the spiny antenna and the
large yellow dorsal knobs as key identifying features. Interestingly
the adult viceroy butterfly is also a mimic of the monarch butterfly
which is poisonous to birds and the viceroy eggs mimic a gall
that invades willow trees.  Sometimes I guess it is good to be
something else!


Thursday, September 16, 2010

Fall Webworm Outbreak

Many of you have probably noticed trees covered with the silk tent homes of the fall webworm Hyphantria cunea this summer.  The webworm caterpillar favors foliage from walnut, hickory, black cherry, elm and fruit trees.  Adult wedworm moths lay eggs on leaves then upon hatching the larvae rapidly consume the soft tissue of the leaf while covering it with a silk surface.  Entire branches of trees can be consumed by the silk tents and in some cases whole trees can be defoliated.  Luckily, most trees are healthy enough to withstand the webworm invasion even in complete defoliation. 
Webworms infest a black cherry Prunus serotina branch.  The
caterpillars are small (less than an inch) in size and are easily
concealed by the silk structure which can contain dozens of
individuals.  A tree with several tent colonies can easily be
defoliated in a matter of days.

Webworm tents in the top of a black walnut tree.  Interestingly
I've read that stinkbugs are efficient predators of webworm
caterpillars as well as parasitic wasps.  However, in a year with an
extreme outbreak, natural predators are overwhelmed and quickly
become engorged with the worms reducing their effectiveness.

Wednesday, September 15, 2010

2010 Drought Continues...

The drought that began in mid-July in eastern Ohio continues to persist and is starting to take its toll on the local foliage. Most of the vegetation is beginning to go dormant or die off completely except those closest to the mainstem tributaries of the watershed.

An up-close view of the drought's toll.  This black cherry tree
along SR 26 has dropped nearly all of its leaves.  Some
defoliation can be attributed to the fall webworm though.
The surrounding trees are about to follow the same route and
are unusually brown.

From the intersection of SR's 148 and 26 - The normally green
hillsides have taken on a yellowish brown tint as trees begin to
drop leaves to conserve water.  There hasn't been a rainfall
greater than .5 inches in the watershed since early August.

Some Interesting Caterpillars

If you've read previous posts on this blog you know that Captina is home to a rich diversity of both woody and herbacious plant life.  Since plants occupy the base of a food chain in an ecosystem we would expect an area with diverse plant life to attract diverse consumers as well.  One of the most fascinating primary consumer groups in the watershed are the caterpillar instars or larval forms of moths and butterflies.  Instars (caterpillars) hatch from eggs laid by adult moths and butterflies on host plants then sustain by consuming leaf tissue.  A single species may transform through several larval instar stages prior to becoming a winged adult which may take over a year's worth of time.  Thus overwintering in leaf litter on the forest floor is common among the caterpillars of this area.

Here are some of the more attractive caterpillars of the Captina Watershed.
A medium-sized caterpillar of the eastern deciduous forest the
pandorus sphinx Eumorpha pandorus is from the hornworm
family and exhibits an interesting arrangement of spots laterally
down its sides.  Note the black spot on its rear topside. 
Pandorus have a liking for poison ivy as a host plant which is
where this individual was found.  They are particularly fond
of new foliage and are about the size of an adult index finger.
Pandorus come in a range of color variants but most center
around a brown or tannish base.

The aptly named saddleback Sibine stimulea.  This individual
was found on a host black locust and yes those are some pretty
intimidating spines.  Some caterpillar species have evolved
amazing camouflage patterns to hide from predatory birds and
insects but the spines are a good backup plan if the trickery fails. 
Fully grown saddlebacks measure up to an inch in length
and can pack a punch with those venomous stingers. 
(Caution! Saddleback stings have been likened to those of
bees.  It is not reccomended that you handle one if found)

Thursday, September 9, 2010

Have you seen one of these?

Hi again!  The postings have been sparse the last couple of weeks due to preparations for the Belmont County Fair.  I thought I would share a couple of interesting pics of a reptile that is native to eastern Ohio but has become rare due to habitat destruction and fear.  Special thanks to Glen Crippen for providing the photos.
The northern copperhead strikes fear in many persons for being
the only poisonous snake found in eastern Ohio.  They are
rarely encountered due to their secretive nature and habitat preference.
Many persons think they see copperheads which end up being
either milksnakes or watersnakes upon further inspection.  The most
telling characteristic of the copperhead is its well-defined triangular-
shaped head and its pupils which are slits as opposed to circles.

As mentioned above copperheads are often confused with
northern watersnakes and milksnakes which have somewhat
similar patterns on their backs.  When compared side by side
the copperhead is clearly distinct due to its dullish color and
width of dorsal bands.  Also the copperhead's body is very
stout and triangular as opposed to the cylinder shaped bodies
of non-venomous snakes.  More later....

Thursday, September 2, 2010

A beautiful afternoon on the creek!

What a great afternoon for enjoying the watershed.
One of the special characteristics of Captina is the lush forested
slopes that rise off of its banks for almost the entire length
of the creek.  This formation is Dover ridge which is  five miles
or so from the mouth of the creek.  Great birding habitat, especially
in the spring.

Looking downstream from a popular local fishing site called "the axle"
west of Dover ridge. 

Dysart Woods

Dysart Woods is an undisturbed, 55-acre tract of forest located in Smith township outside of Centerville. It is owned and managed by Ohio University as a field research facility and contains some of the largest diameter trees left in the Captina watershed.

It is not uncommon in the Dysart preserve to see old growth trees
like this white oak.  It is easily 8 feet dbh and 80-100 feet tall.  County
forester Nathan Taylor is impressed - tree hugger : )  

A rareity for the watershed - a native persimmon.
Persimmons produce edible fruit but Belmont County
is on the far northern reaches if its native range.
Note the squarish segments of bark that distinguishes
it from a black gum.  There are two mature persimmons
next to the blue trail of the preserve.

Dysart Woods is home to native black gum as well which is
identifiable by its thich, furrowed bark and deep red fall foliage.

The thick forest canopy traps moisture and creates ideal growing
conditions for a variety of mushrooms.  These are growing at the
base of a dogwood tree.