Wednesday, September 30, 2015

Fall Orchids

One of my late September rituals is to make the rounds to admire the final orchids of the year.  Spiranathes ovalis is a late season orchid that is uncommon in Ohio, but which has been steadily increasing its numbers at Blue Jay Barrens.

I find Spiranthes ovalis typically growing at the base of steep wooded hillsides and the adjacent gently sloped area between the hill and the creek. 

The demure plants are difficult to find among the fallen leaves and competing vegetation in the shadows of the trees.  My initial discoveries are always made on the walking trails.  The trails typically get mowed twice each summer.  The second mowing is done in late August, prior to the elongation of the orchid flower stalk, so I don’t accidently decapitate one of these lovely flowers.  The orchid in the above photo is located in the lower right hand quadrant.

Blooms are withering on plants that opened their flowers early in September.  Many of the plants only produce a few flowers.

Others produce long spikes.  I’ve tracked many Spiranthes ovalis plants through the years and have found that they usually persist for four or five years before disappearing.  Even if a plant doesn’t flower in a given year, it will produce a cluster of basal leaves.  If a few years pass without leaves appearing, I assume the plant is dead.  Fortunately, new plants always seem to be emerging to take the place of those lost.

The second late season orchid, and my personal favorite, is Spiranthes magnicamporum.

This species is capable of producing some very robust flower spikes.  The flowers are not only large and attractive, they produce a strong scent.

There are a few individual Spiranthes magnicamporum plants scattered around Blue Jay Barrens, but only two areas where you can find a concentration of plants.  This past Sunday, I found a dozen plants blooming here.  Shallow, rocky soil with patchy vegetation typifies the conditions in which I am likely to find these plants.

The second site of Spiranthes magnicamporum plants is slightly steeper than the former, but no less barren.  This site had a large number of blooming plants last year.  I counted only seven this year.  It’s rather hard to predict just how well the orchids are going to do in any given year.

Not only were there fewer plants this year, those plants present developed flowers spikes much shorter than normal.  This species is also increasing in number.  That means it is more likely that I’ll find a few large, impressive plants each year.

Wednesday, September 16, 2015

What's Eating the Redbuds?

When people ask me what ornamental tree I would recommend for home landscaping, Redbud is generally my instant response.  My reason for this response typically causes my inquisitors to lose interest in my opinions.  They are expecting me to make some point about the beauty of the tree or the rapid rate at which it grows or the fact that it doesn’t get large enough to fall over and smash your house, but I like Redbud because it is a preferred food of so many animals.  From the time the first flower bud begins to open in the spring until the last leaf drops in the fall, something is consuming the Redbud.  About 20 years ago, I planted two Redbuds at the corner of my garage, so I could more easily follow the season long parade of Redbud predators.  These trees have since grown tall and lost most of their lower branches.  From below, I can see the chewed leaves and know that something interesting is living above.

Fortunately, the trees I planted have spread many seeds.  I’ve let some of the resulting seedlings grow along the side of the garage, so I can have a few Redbud branches at my eye level.  Many different types of animals feed on the tree through the year, but in September it’s the caterpillars that dominate.  I took a few minutes to photograph some of the current residents.

First off, I should probably mention the species that actually targets the Redbud over other plant species.  The Redbud Leaf Roller can likely be found on any Redbud Tree.  Because of its habit of folding over a leaf edge and webbing it in place to form a sanctuary in which to feed, the Redbud Leaf Roller is not seen by many people.

You have to unfold the leaf to reveal the creator.  These caterpillars are known as skeletonizers because of their habit of leaving the leaf veins and a thin layer of tissue behind as they feed.  Inside the fold of the leaf, the caterpillar eats and leaves its droppings.  A nice little package that hides most evidence of the caterpillar.

Hanging by lengths of silk, these small green caterpillars disperse themselves around the tree.  It doesn’t make sense to me that they are all just accidently falling off of their leaves.   It seems like poor survival skills to be unable to keep hold of your food supply.  Some of the caterpillars keep lowering themselves until they arrive at another leaf.  Others sway in the breeze and grab onto leaves or branches.  Still others climb back up their thread, apparently arriving at the end of their tethers with nowhere to go.  I think much of their activity is in an effort to scatter themselves around the area.

I believe these thread travelers are early instars of the Redbud Leaf Roller.  I’ve found many living in refuges made by webbing together the edges of two neighboring leaves.  Perhaps the younger caterpillars do not have the strength to fold a leaf edge over on itself and take advantage of an already occurring situation.

Colorful caterpillars are always more colorful when they come in a group.  These are early instars of the Red-humped caterpillar.  Like most of the caterpillar species found on the Redbud, these caterpillars feed on a variety of woody plant species.  A few end up on the Redbuds each year.

The final instar of the Red-humped caterpillar.  Having groups of different ages suggests that more than one female planted her eggs on this tree.

Fall Webworms are also generalist feeders, but they never miss laying eggs on the Redbud. 

A mass of webbing is generally the first indication of Fall Webworms.  The group stays together until its final instar.

The last stage caterpillars head off on their own, sometimes staying on the original host tree and other times wandering to a new location.

The caterpillar of the American Dagger Moth.  I personally think of this as the English Sheepdog caterpillar, because of the mass of hairs hanging down over the face.

Here’s a caterpillar that’s often overlooked as a bit of fluff.  This is the early instar of the Black-waved Flannel Caterpillar.

Final instar of the Black-waved Flannel Caterpillar looks quite different from its earlier edition.

Skiff Moth caterpillars don’t look at all like living animals.  They look more to me like galls or other plant deformities.

Their coloration can vary.  This one carries an image on its back that looks more like a birds face than do many actual bird’s faces.  This should certainly startle any predators approaching from the rear.

The Yellow-shouldered slug.  This is one of many caterpillars collectively called slug caterpillars.  It’s easy to see why they were given that designation.  Most in the group are slow moving and look like an oblong blob.

You may not guess it from the name, but many of the slug caterpillars are the showiest caterpillars around.  This is the Saddleback Caterpillar.  Those spines are far from being just ornamental.  I’ve received five stings from this species this year: Two shoulder, One arm, One neck, One ear.  It takes my body about 30 minutes to deal with the toxin and get back to normal.  This caterpillar routinely sits near the edge of the lower side of the leaf with the tips of the spines sticking out.  That makes it very easy to accidently brush against the spines.

The Spiny-oak Slug is another stinger, but it generally doesn’t spend so much time at the edge of the leaf.  This is a variable species that can display a wide range of color patterns.

A real winner in the color category is the Stinging Rose Caterpillar.  The warning here is included in the name.  It may have the appearance of a fancy piece of hard candy, but this is one morsel you don’t want to touch.

The black and white pattern of the Hickory Tussock Moth caterpillar reminds me of white Bengal Tigers.  This specimen seems to be shedding.

I found many of this species on the Redbud, but wasn’t finding much evidence that they were feeding.  There was a chance that they were just migrating over from some nearby Black Walnuts, a favorite food plant.  Then I found this guy carving a large hole in the middle of a Redbud leaf and decided that they must also eat Redbud.

There are also several caterpillars that I can’t put a name to.  This little guy had three parasitoid larvae riding its back.  I found this curious because the caterpillar was trudging along as though nothing was wrong.  Typically, the parasitoid larvae would feed and grow inside the caterpillar and then emerge to spin cocoons and pupate on the caterpillar’s skin.  As large as these larvae are, it seems there would have been little left if they had been feeding inside that small caterpillar.  The caterpillar should have at least moved sluggishly or remained stationary as I’ve seen so many other caterpillars do in similar situations.

Finally, this European Hornet, which is not a caterpillar of any kind, searched leaf after leaf and appeared to be following me as I examined the Redbud.  I thought it might be hunting caterpillars, or some other creature on the tree, but it never seemed to find anything.  I’ll just add its behavior to my enormous list of things I would one day like to understand.

Wednesday, September 9, 2015

Treefrog Tadpole Rescue

This has been a year of flood and drought at Blue Jay Barrens.  There have been several heavy rain events that dropped inches of water in a short amount of time.  Each rain was then followed by several weeks of dry weather.  Temporary pools have been appearing and disappearing all summer.  A two inch rain in mid-August produced an eight inch deep pool in the dry pond bottom.  Gray Treefrogs took advantage of this event to fill the pool with eggs.  

This week, a small puddle was all that remained of that pool.  During the last few days, hundreds of young treefrogs managed to reach the four legged stage and migrate from the pool to the surrounding vegetation.  This photo shows the puddle with just one day of life left.  The following day, the area went dry.

Because the original breeding event spanned more than a week, the young from the later eggs were not developed enough to leave the water.  Without intervention, they would all perish.

By the time I arrived with net and bucket, the mass of tadpole bodies seemed greater than the water they were in.  I like to make the classic rescue just as the clock ticks down to its final second.  When the shrinking pool crowds the tadpoles together nose-to-tail, it’s easy to herd them all into a waiting net.

The first of many nets full make it into the bucket.  A few aquatic insects and snails managed to sneak in with the tadpoles.

An expanding sediment cloud marks the release of a bucket full of tadpoles into the water garden.  Further releases were made into any tub I had that contained enough water to sustain tadpole life.

Many of the tadpoles were at the four leg stage and needed only a few more days of aquatic life.

Two days following the rescue, I found many young frogs making the transition to a terrestrial life style.  Most still displayed a remnant of their tail.

It has been many years since the Gray Treefrogs have had such a successful breeding season.  During the past six weeks, I have encountered one or two young frogs every day.  I’m glad I was able to assist in adding several hundred more frogs to this year’s output.

Wednesday, September 2, 2015

Elephant Mosquito Returns

Back at Blue Jay Barrens after a five year absence, by popular demand, it’s the Elephant Mosquito, Toxorhynchites rutilus septentrionalis.  A behemoth of the mosquito world, this non blood sucking species is the largest mosquito to be found in North America.  I found this larva, posing beside its normal sized relative, living in a tub of water beside my house.  This is a southern species whose range extends into the lower half of Ohio.  It’s possible that the species has trouble surviving Ohio winters.  If so, the Ohio population would depend upon more southern populations moving north each year to recolonize this area.

Elephant Mosquitoes are predators, feeding on small aquatic organisms.  Its diet consists primarily of the larvae of other mosquito species. 

Eating is the primary activity of the Elephant Mosquito larva.  This one is consuming a double helping at one time.  The larval stage can last from a few weeks up to several months.  I’m sure that temperature affects the rate of development, but I would guess that the available food supply is also a critical factor.

Even though the larva will grab prey whenever presented with the opportunity, most of the active hunting seems to occur at the water’s surface.  Floating with a collection of potential prey items, the larva will raise its body into a horizontal position and slowly reach out towards its prey.  When it gets within range, it give a quick lunge and grabs the prey with its strong set of mandibles.  I watched this individual, which is now housed in a small aquarium, consume six mosquito larvae in 20 minutes.  It has since greatly slowed its rate of consumption.  I believe my supplying the Elephant Mosquito with a density of food items about 25 times greater than what it was used to might have been the cause of the initial glut.

This is typically a tree hole species that breeds in water pockets trapped inside tree cavities.  I imagine one of these predators could easily clean out the mosquito population in a small pool.

The Elephant Mosquito larva is primarily an eating machine.  Fortunately, the large sized adults feed on nectar and other plant juices, so are no threat to people.  Click HERE for more information on this insect and details of its first discovery at Blue Jay Barrens.

Blogger is not letting me upload videos today, so I've included three links to videos showing typical hunting behavior for this species.  Click HERE 1 and HERE 2 and HERE 3 to view the videos.  For best viewing, select the full screen option on YouTube.