Thursday, September 30, 2010

Fifteen Minute Caterpillar Hunt

People often question how I manage to find so many different things when I’m out walking. I reply that I just look. A nameless person suggested that I must have a bird’s perception to be able to look at a bush and see a caterpillar, or did they mean that I must have a bird’s brain. I’ll have to think about that. Anyway, as a demonstration of finding things just by looking, I walked back to an area of small shrubs and trees and gave myself fifteen minutes to find as many caterpillars as possible. This leaf tells me that caterpillars have been here.

A caterpillar skin. A shed skin suggests that there should be a larger and easier to spot caterpillar somewhere nearby.

Searching for one thing doesn’t mean you ignore everything else. I enjoy each new discovery as it comes along. The oak leaves are developing some wonderful galls. I’m not sure how large these pea sized growths will eventually become.

Here’s a neat insect. I’m guessing it to be some type of predatory bug. The front legs are much stouter than the rest and are held together in much the same manner as the front legs of a mantid. I can imagine those legs holding onto some small insect while the juices are sucked out.

The Bladdernuts have produced several fruits this year. The fruit looks like it could provide a lot of good eating, but inside is mostly air with a few small seeds.

This is a beautifully colored assassin bug. I don’t remember ever seeing a specimen with this yellow and black pattern. He wasn’t very tolerant of my presence and flew just after I took this shot.

The nuts are ripening on the Common Hazel. The leafy bracts turn the nut into a piece of art. That’s the end of my fifteen minutes. I tallied zero caterpillars, but that doesn’t matter. I found some really neat things while looking. Things that I never would have seen had I not gotten close enough to discover them. I often go searching for specific things, but I never let that objective keep me from enjoying all the other natural wonders that are out there to be found.

Wednesday, September 29, 2010

Caterpillars

This has been a year of abundant butterflies and moths at Blue Jay Barrens and now, as you might expect, I am seeing an abundance of caterpillars. Every tree and shrub is showing signs of feeding damage to the leaves and it doesn’t take long to discover the feeders. The last time I was out, I ran into a couple of my favorites. This little beauty is the Spiny Oak-slug, Euclea delphinii.

This is one of those look-but-don’t-touch species. Those spines are venom filled and can deliver an irritating sting. I’m always glad when I see the caterpillar before accidentally brushing against it. The spines are arranged to give defense from above or from the sides.

The bright coloration of this caterpillar is a warning to stay away. From a distance, the bright yellow is muted and begins to look like just another leaf adopting its fall colors.

When I see long tufts of hair adorning the head and tail of a caterpillar, I automatically think tussock moth. Most caterpillars with this feature represent a species with tussock in its common name, even though they represent many genera scattered through several families of moths. Here is the Banded Tussock Moth, Halysidota tessellaris.

This is a very common species that often sits out in the open on top of leaves. The head is partially hidden by several tufts of long, feathery hairs. I suppose the tufts have something to do with camouflage or defense. What I really like about these caterpillars is the magic act they perform when disturbed.

Suddenly, the head becomes the butt. Like a turtle withdrawing into its shell, the caterpillar pulls in its head and first segments so that the arrangement of tufts mimics the rear end. Many predators attack the head of the prey and having the head suddenly disappear could confuse a predator enough to make it move away. Whatever the reason, it’s a neat little trick to watch.

Tuesday, September 28, 2010

Walking Stick

Any outing is enhanced by the discovery of a Northern Walkingstick, Diapheromera fermorata. I would probably see more of these guys if I spent my time in the tree tops where Walkingsticks tend to hangout. I get the impression that most low elevation Walkingsticks are just making their way back upward from an unexpected fall. Of course, the fact that they are so well camouflaged also accounts for the scarcity of finds. Sometimes they look more like sticks than do real sticks.

The front pair of legs attaches to the body just in back of the head. When at rest, the front legs are held straight above the head so as to appear a continuation of the stick body. The eyes and other parts of the head are fashioned to resemble buds.

The front legs are shaped so they can wrap around the head to produce the appearance of a single piece. Every part of this creature lends itself to creating the image of a stick.

I’m not sure what this end looks like. Certainly not an insect part. Despite the stick-like appearance, Walkingsticks are tasty morsels and will be readily taken by birds. I imagine it would be quite awkward to have a bird mistake this as a perch.

Even the legs have ornaments to help with the masquerade. Short appendages near the joints look exactly like pointed buds. It may look an odd creature, but it’s marvelously suited to its arboreal existence.

Monday, September 27, 2010

Dry Dogwoods

There’s a chance of rain today, but the effects of a ten week drought cannot be reversed. Blue Jay Barrens experienced excessive rainfall early in the year. It looked like plants might grow out of control, until the rain suddenly shut off in early July. During the past 6 weeks we have had only 0.15 inches of rain and that came in three separate showers. A drought becomes really serious when it begins to affect the shrubs and trees. The Flowering Dogwoods, Cornus florida, have become prime examples of drought stressed trees.

The bright red of the autumn dogwood leaves will be lost from the landscape this year. Many of the leaves are already brown and crisp. The others are too far gone to recover, even if we get abundant rainfall today.

The fruit seems to be alright. The seeds are fully developed and the red fruit should be attractive to the birds.

Most of these dogwoods were just recovering from the periodical cicada damage they suffered two years ago. This isn’t the first drought they’ve endured. I expect them to survive, but their start next year may be a little less vigorous than normal.

What happens to these buds will determine what things will be like next year. These enlarged terminal buds will be producing the flowers next spring. Continued dry weather could impair the development of the buds and cause a lack of flowers. No spring flowers means no fall fruit, so weather conditions during the next few weeks could have a major impact on fruit availability next year.

Sunday, September 26, 2010

Southern Two-lined Salamander

Although common across the southern half of Ohio, the Southern Two-lined Salamander, Eurycea cirrigera, is a rarity at Blue Jay Barrens. This salamander is normally found along small streams in rocky wooded areas. Perhaps the frequency of drought at this location makes it difficult for the population to persist.

The name comes from the lines running along the edge of the salamander’s back. I probably would have named it the golden-backed salamander because it’s the bright yellow-gold coloring on the back that I first notice when I encounter this species.

Salamanders are always fun to encounter. They seem so fragile that it’s a wonder they can survive any type of adversity. I’m amazed each time I find a salamander apparently thriving in this dry landscape.

I found this guy beneath a log in the dry creek bed. There seems to be enough moisture in the creek gravel to keep the underside of the log hydrated, so this is a perfect place for a salamander to wait out the drought.

Saturday, September 25, 2010

Rosette Gall

When I see a tightly packed rosette of leaves such as these, I think of a ground hugging plant. Many species of plants begin development as basal rosettes before sending up flower stalks. This, however, is not that type of plant.

This rosette forms on top of a stalk and is normally a couple of feet in the air. It’s an interesting plant, but that is certainly an odd stalk topper. The plant is the Canada Goldenrod and the cluster of leaves is a gall formed by the larva of a tiny midge.

The female midge, a type of small fly known as Rhopalomyia solidaginis, lays its egg in a bud at the growing tip of the plant. When the egg hatches, the presence of the larva inhibits stem elongation, so the plant grows no taller. Leaves continue form and develop one atop the other until you have a tightly packed cluster.

The plants still manage to flower despite their lack of height. The midge doesn’t hurt the seed producing potential of these plants even though the total flower production is slightly diminished.

Cut in half, the gall looks much like an artichoke. Without the interference of the midge, each leaf would have been separated by a section of stalk.

The cluster of leaves provides a place of safety for the midge larva to grow and pupate. The leaves will brown and whither over the winter, but the gall will hold together and continue to provide protection to the pupa. The adult midge will emerge next spring.

Friday, September 24, 2010

Goldenrod

Sections of the field are beginning to flush yellow as the Canada Goldenrod, Solidago canadensis, finally begin to bloom. Goldenrods produce chemicals through the roots that inhibit the growth of certain plants. This reduces competition and allows the goldenrod to quickly spread through underground rhizomes. For this reason, goldenrods often produce almost solid stands.

Goldenrods produce some beautiful flower clusters. Many people shy away from these lovely flowers because they believe them to be the source of their hay fever symptoms. Actually, the goldenrod has heavy pollen that is transported by pollinating insects and leaves most people unaffected. It’s the ragweed that produces the airborne pollen that irritates so many nasal passages. The fresh flowers can be cut and dried to serve as a reminder of autumn’s splendor through the cold winter months.

The mass of flowers is called an inflorescence and is composed of many short branches all bearing tiny flower heads. The arrangement of the flower heads on the branch is one of the characteristics used in goldenrod identification.

Goldenrods probably have the most insect activity of any fall flower. Many insects are goldenrod specific and the goldenrod plant almost becomes an ecosystem by itself. This bloom harbored a collection of aphids of two different sorts. The red individuals are easy to spot, but there’s also a larger type with a green coloration that makes it blend perfectly with the goldenrod stem.

Wasps of all types visit these flowers. I’ve watched various wasp species drink nectar, nibble pollen, chew petals and hunt insect prey on these flowers. This is a wonderful way to view wasps, because they are not protective of the flowers and let you get up close without threat. You’d never be able to get this close to a wasp on its nest without eliciting some type of defensive action.

Crab spiders are everywhere among the goldenrods. This appears to be Misumena vatia, the Goldenrod Spider. Coloration in this species is quite variable and the individuals have a limited ability to change color. The ant rushed over to chase off the spider. You can see how things got turned around.

Thursday, September 23, 2010

Tall Boneset

If you like white flowers, Tall Boneset, Eupatorium altissimum, could well be your favorite. Blooming begins in the summer, but plants are at their showiest in early fall. Clusters of the small flower heads can grow into large aggregations that look like tiny cloud formations drifting across the landscape.

Tall Boneset is commonly found throughout the tall grass areas of Blue Jay Barrens. This is because it is an aggressive plant that grows very well on the dry, shallow soils found here. Plants growing in better soil conditions sometimes create flower clusters too heavy for the stout stalks to hold aloft. Rain or heavy dew often adds enough weight to take these overlarge plants to the ground.

Tall grass doesn’t hinder the development of this plant. Like many of the tall prairie plants, a single long stalk reaches up to a point that allows branches to spread and develop flowers. The flowers are held high enough to be easily visited by pollinating insects.

Right now is the absolute peak time to view these flowers. The first flower heads have just begun to release ripe seeds. From this point on, seed loss will cause the flower clusters to take on a more gray appearance. Most of the seeds develop at about the same time and the flowers will look like a fuzzy mass as the pappus, those feathery little projections attached to the seed, dry and spread.

There are several species of Boneset with almost identical flowers. Other characters often need to be checked to make a proper identification. The long, narrow leaves of the Tall Boneset usually have a few teeth along the margins. One easy to see feature is the set of three heavy veins running the length of the leaf.

Insect activity abounds on these plants. The flowers themselves attract a wide variety of visitors and the rest of the plant has a swarm of active residents. Treehopper larvae are being tended by ants on this plant. A plant in harmony with insects always seems to be more complete.

Wednesday, September 22, 2010

Black Walnut

The person who sold us our house had a liking for Black Walnut and planted several of these mighty nut producers in the yard. If you’re going to maintain a patch of mowed lawn, the last thing you should consider planting is something that produces thousands of hard, round balls that drop for weeks in the autumn. My solution was to just stop mowing under the trees. At least Black Walnut is native to this area.

I really like the openness of the Walnut canopy. It always reminds me of the airy trees scattered across the African Veldt.

My real aggravation comes from the forest of walnut trees that develop from the scattered nuts. Some people have elaborate methods for making walnuts germinate. At my house, all you need to do is let the nut hit the ground and you get a new tree. Squirrels and Chipmunks have helped distribute nuts far across the field and I am constantly trying to eliminate the resulting saplings.

Black Walnut is a common tree of the old fence rows. The origin of the trees is the question. Are any of these trees descended from a lineage native to this site or were the parent plants brought in from somewhere else?

Our shallow soils may be perfect for sprouting walnuts, but they provide terrible growing conditions. Walnuts grow best in deep soils. When the roots are stopped by shallow bedrock, the tree begins to suffer. Frequent branch die back, twisted trunks, rotten cavities and multiple trunks are common characteristics of the trees that grow here. These are not the trees that timber buyers dream of. Of course, producing timber is not one of my goals.

There are some older Black Walnuts in the old fence line. This specimen bears the scars of old fence wire. A 1938 aerial photo of the property shows a tree growing in just this location. I believe this is the tree I’m seeing in the photo, so I can imagine the age being near the 100 year mark.

In a little valley below the barn, a group of younger walnuts put on some rapid height in the deeper soil. The root system of Black Walnuts produces a chemical called juglone, which is toxic to many types of plants. As a result, a community of juglone tolerant plants develops in association with the walnuts. The ground cover in this valley changes dramatically as you move out of the walnut dominated area.

Walnuts on the other side of the barn show signs of having been planted in rows. I wonder if past generations had a similar interest in planting the valuable Black Walnut. I have not found any Black Walnut trees in the wooded portion of Blue Jay Barrens. That doesn’t mean they were never there. Walnut would have been readily cut if it had even the slightest economic value and could have been eliminated from the woods decades ago. The origin of Black Walnut at Blue Jay Barrens is just one of those things I ponder when I’m in a pondering mood.