Common Milkweed

Common Milkweed is now in full bloom at Blue Jay Barrens.  Common Milkweed has a strong network of rhizomes that allow a single stalk to become many in a short amount of time.  Milkweeds have just about surrounded the Water Garden this year.  I had to remove some stalks from the driveway and a couple more that were threatening to block access to the front porch, but there are still plenty left for the Monarch butterflies and other animals.

Milkweeds form a mass of flowers whose stalks all originate from the same point, a form known as an umbel. The large number of flowers found in each umbel typically cause the umbel to appear in the form of a sphere.

The petals fold back to reveal a central column of reproductive parts which is surrounded by a set of five two-part structures known as the hood and horn.  This arrangement has always reminded me of the old dental spit-sink with a hooked claw emerging from the drain.

Milkweeds do not produce the dust like pollen common in many flowers. To affect pollination, an insect carries a pollen mass, known as a pollinium, from one flower to another. A knot like affair joins two pollinia by short threads.  The insect’s foot or leg catches the thread and pulls the pollinia from a slit between the hoods. The photo above shows the location of the slit with pollinia still intact. Above that is a pair of pollinia that have been removed from the flower. I guess a flower needs to attract a wide range of insect visitors when pollination requires an incidental snagging of a pollen mass followed by the proper placement of that pollen mass on a new flower.

Milkweed flowers attract a wide range of bee species, from large…

… to small.

Some insects are attracted to the milkweed plant not by the flowers, but by other flower visitors. This is a Conopid fly.  Conopid larvae are parasitic on bumblebees. The Conopid adult will attack a bumblebee in the air, force apart two abdominal segments, and lay an egg in the abdomen of the bumblebee. The larva consumes the bumblebee from within over the course of a couple of weeks. The action of this parasitic consumption causes the bumblebee to dig a hole and bury itself before dying, providing the Conopid larva with shelter in which to pupate and overwinter.

Like many other insects, the Conopid Fly uses mimicry to help avoid predation. In this case the fly looks suspiciously like a wasp.  Would-be predators, fearful of a stinging response, are more likely to pass this fly by.  The easy way to tell the difference between a fly and a wasp is to count the wings. A wasp has two pairs of wings, while a fly only has a single pair. In lieu of the second pair of wings found on bees and wasps, a fly has a pair of structures known as halteres.  Halteres help to balance the fly in-flight. In the photo above, the two white objects at the rear of the thorax are the halteres.

Highly colorful Long-legged Flies flit about the leaf surfaces of many plants. The large milkweed leaves seem to particularly attract this insect.

It wouldn’t be a milkweed plant without Milkweed Bugs. Milkweed Bug pairs are often in mating tandem at this time of year. The reproductive process is not going to stop the upper bug from probing the milkweed flowers for a meal. The lower bugs is dragging around a pair of pollinia on its middle foot. The pollinia will be wasted if not deposited into an open flower.

Goldenrod Soldier Beetles are also busy with courtship rituals. These beetles are pollen eaters and will visit many species of flowers besides their namesake Goldenrods.

The milkweed flowers are brightly colored, strongly scented producers of abundant nectar. Most moth visitors appear after dark and are rarely noticed.  The Hummingbird Clearwing is one of the few brightly colored moths that visit the flowers during the daytime.

Many species of skippers are attracted to milkweed. This is the Silver-spotted Skipper, one of the largest and most easily recognized of that group.

Butterflies of all sizes visit milkweed. On the smaller end of the scale are the tiny hairstreaks, like this attractively marked Banded Hairstreak.

Great Spangled Fritillary butterflies have been mobbing some of the milkweed flowers. If your interest is in viewing butterflies, and other interesting animals, it’s worth encouraging a few Common Milkweed plants to live somewhere near your house.

Still photos don’t do justice to mobbing butterflies, so I offer the short video above.

Monarda Returns

It’s been a few years since Monarda fistulosa has bloomed so prolifically in this opening at Blue Jay Barrens.  Something about the environmental conditions during the winter or spring of 2011 caused a massive die-off of Monarda plants in this patch. 

During the past few years, Monarda has returned and is now approaching its earlier abundance.  With the return of the plants comes a return of the butterflies.   Monarda attracts a variety of pollinator species, with large butterflies being the most notable.

At the small end of the size scale is the Silver-spotted Skipper.  Smaller butterflies, which includes the other skippers and many butterfly species, seem to find the Monarda flower head difficult to handle.  As if in celebration of the return of the Monarda, Silver-spotted Skippers are around in record numbers this year.

The showiest of the butterfly visitors are the Swallowtail species.  This is the Spicebush Swallowtail.  Its habit of constantly fluttering its wings while feeding makes it difficult to photograph.

Blooming of Monarda seems to coincide with the emergence of the summer brood of Tiger Swallowtails.  Summer brood individuals are typically larger than those found earlier in the year and they are quite showy as they glide between Monarda blooms.  There are those that exhibit the typical yellow coloration and …

… others that are colored a silky black.  Despite their black coloration, the tiger stripes still show through.

I found it interesting that the swallowtails all seemed to feed while hanging from the side of the flower head.

Great Spangled Fritillaries, however, tended to do their feeding while perched atop the flowers. 

The Monardas have even attracted a few Giant Swallowtails.  The Giant Swallowtails quickly move from flower to flower, spending so little time nectaring that I sometimes wonder if the act is even beneficial.  Finding them at flowers is about the only way to get a decent look at these fast fliers.

The Monarda is most famous as an attractor of Clearwing Sphinx Moths.  Using their front legs as anchors, Hummingbird Clearwings hover next to the flower as they draw nectar.  This species is currently outnumbering butterflies in the Monarda patch.

A few Snowberry Clearwings are also present this year.  Slightly smaller than the Hummingbird Clearwings, the Snowberries feed in a similar manner.  This is a species that I don’t often see here.

The Monarda’s attractiveness is not diminished by darkness.  A variety of moth species visit the flowers through the night.  The lack of multiple examples of nocturnal visitors more accurately reflects the photographer’s skills than it does the true number of night-time pollinators.

Absent Monarda

Things always change. Sometimes it’s a slow gradual change that allows you to adjust to the new conditions. Other times it’s a quick change that leaves you wondering what happened. The Monarda fistulosa has given me both this year. At the slow end of the scale is another slight increase in the size and numbers of Monarda populations.

The quick change took place here at the site of my oldest and largest population of Monarda. The level center section of this small valley has always provided an almost solid blanket of Monarda blooms that brought in swarms of bees and butterflies. As you can see, the flowers are not here now.

This area was solid with Monarda blooms last year. Now Monarda is completely absent; not just the blooms, but also a complete absence of plants. There is some Monarda growing in the background where the ground begins to rise from the valley floor. During the late winter and spring, the level part of the valley was frequently inundated and was almost constantly saturated. This amount of moisture is uncommon, but it has happened in the past without loss of the plants.

The fact the slightly higher and drier ground around the perimeter of the site still contains a good stand of Monarda, makes me think the water was somehow a factor in the disappearance. This same site suffered a Monarda die-off about seven years ago when the plants were all killed back by a late freeze. It took a couple of years, but the Monarda eventually returned. I expect that the plants will once again reclaim this area.

The most disastrous effect of the Monarda disappearance is the loss of a prime gathering area for the Hummingbird Clearwing Moth. There are still plenty of flowers scattered around, so the moth population shouldn’t be hurt, but I’ll really miss the spectacle of dozens of these magnificent moths buzzing around the same small area. Maybe with no moths to distract me, I’ll see something even more wondrous.

Hummingbird Clearwing

This is a moth known as the Hummingbird Clearwing. The name clearwing comes from these transparent areas of the wing.

A lot of people are confused by this species because of its habit of flying during the day and hovering at flowers to drink nectar. This is the source of stories about dwarf hummingbirds.

Hummingbird Clearwings are seldom still and are best observed by staking out a likely clump of flowers and waiting for the moths to come over. They stop briefly at each flower and tether themselves with their front legs while drinking.

I’ve never seen one of these moths stop and rest. The wings are in constant motion.

The long haired body is a beautiful mixture of olive, brown, crimson and black. This is a common moth that could be seen anywhere in Ohio. It should be flying for several more weeks, so watch for it in your area.