Learning New Things

Sunday I went to the winter meeting of the Iowa Prairie Network, and attended a workshop on milkweeds by Tom Rosburg and Deb Lewis.  There was a lot of good information about how milkweeds are pollinated.  I knew a little about it as a consequence of the time I have spent photographing insects, especially butterflies, and especially on milkweeds.  There was also some information that was new to me and that I had not really thought about.

First of all, Iowa has 16 species of milkweed.  This one is called prairie milkweed, Asclepias hirtella.

Milkweeds have an unusual type of pollination.  Pollen grains in milkweed flowers are combined in the flower into a structure called a pollinium–in milkweeds this is a saddlebag-shaped structure.  The structure has a large number of pollen grains covered with a waxy coating.  Orchids have a similar arrangement but in most flowers the pollen grains are separate.

If you look closely at the hind leg of this wasp, you can see a milkweed pollinium dangling from it.  The flower is swamp milkweed.

A good discussion of milkweed pollination can be found here.

Common milkweed is very attractive to a wide variety of insects, especially hairstreaks.  These banded hairstreaks both have pollenia on their legs, so are likely pollinators of the plant.

Just because an insect is attracted to milkweed does not mean that it is a pollinator.  This beefly is attracted to the flower but is not likely to collect the pollenia on its legs like butterflies do.

 Pollination of milkweeds is mostly accomplished by large insects–butterflies, large wasps and bees (although the bees do not collect the pollen like they do for other flowers), flies, and beetles.

One of the consequences of this type of pollination is that statistically it is not likely to happen.  Flowers are on umbels of several dozen flowers.    We have all seen milkweed pods.  The botanical term for those pods is “follicles”

These are follicles for common milkweed.  Each milkweed plan can have a few follicles–maybe as few as two, maybe as many as a half dozen.  Compare that with the total number of flowers produced–many dozens of flowers.  Five percent or less of the flowers produced actually got pollinated.

One pollinium produces all of the pollen for each follicle.  Therefore all of the seeds in each follicle have the same mother and the same father.  Male and female parts are found on each milkweed flower, and the milkweeds are not able to self pollinate.

There is a plant found here in Iowa that is in a group close to milkweeds.  That plant, Indian hemp or dogbane, Apocynum cannabinum, has a milky sap similar to milkweeds.  Like milkweeds, it is very attractive to butterflies.  It does not produce pollenia, but has pollen that sticks together in groups of four.

There is a discussion of pollination in dogbane here.  It also touches on why pollenia might have evolved.  The hypothesis discussed suggests that this arrangement uses less pollen than the flowers would use otherwise, and therefore saves energy for the flowers.  I am not sure I buy that.  It seems to me that it might have more to do with competition for the resources used by the plant to set seed.

Apocynum cannabinum produces a follicle similar to milkweeds, but each seed would not necessarily have the same male contribution like in milkweeds.


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Best Photos of the Year

I put together a bunch of photographs which I think were my ten best for the year.  I don’t feel too verbal now, so here they are, just the photos:

Thanks for viewing.

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Ears on the Wings of Butterflies

Sometimes there will be little news items about scientific papers.  One that made some of the news blurbs lately was about a study that showed there were ears on the wings of some butterflies.  The paper that made the news studied inflated veins that are found on common wood nymphs, and found that it assisted the butterfly with hearing.

Another recent paper studied the blue morpho butterfly and its ability to hear.  Hearing in butterflies is accomplished with a tympanal membrane, which in certain groups of butterflies is called the Vogel’s organ.  Hearing in insects in general is through tympanal membranes located in various areas–on the legs, for example.

I thought I would look for the Vogel’s organ (the ear) in butterfly photos I have taken, and also the swollen vein that was mentioned in recent paper.  The Vogel’s organ is very small, and covered with scales and hairs.  I am not sure I have a clear photo of one.

This is a northern pearly eye.  The white dot at the end of the arrow might be the Vogel’s organ.  Hard to tell for sure.

Question mark butterfly and maybe the Vogel’s organ.

This is a little wood satyr.  To the left of the red line is the swollen vein that has a function in the hearing of the butterfly.

This is a common wood nymph, also showing the swollen vein to the right of the red line, and possibly the Vogel’s organ.

So I am not sure I have it.  Maybe I would need to have the butterflies in hand to know for sure.

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Late Season Pollinators

Sunday I went to Marietta Sand Prairie (right after Iowa State won their ball game).  I was hoping to find some late season insects.  I had not been out with my camera for a few weeks because the weather and my schedule did not cooperate.  I was only there for a short time–there were pheasant hunters out, and as I was not wearing blaze orange it seemed like it might not be very wise to be crawling around in the weeds.

There were not a lot out anyway, and not many flowers.  But there were a couple of very late flowers blooming by the parking lot, with some insect visitors.

I am not sure what this tiny bee is.

I was surprised to see this butterfly so late in the year.  Clouded sulfur, I believe.

I think this small bee could be Sphecodes davisii.

Flowers are now difficult to find, as are the flower visiting insects.  The season is mostly at an end.  For a few months I will sort pictures and take macro photos inside instead of out in nature.  And that is not nearly as much fun.

But spring will come soon enough.


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Late Season Critters

Our weather has cooled down lately, particularly at night.  It is still warm enough for most of the insects though, so I went to a backwater area of Big Creek State Park and took some photos.

This eastern tailed-blue was mudding near the water.

A female eastern forktail was hanging out near the edge of the water.

New England aster is a native plant, often seen growing in the ditches.  This plant is very attractive to insects like this small bee.

In fact, the flowers were covered with several pollinators.

There were a few pearl crescents flying around as well.

Flowers are still blooming, and the insects are still flying around.  But they won’t be for long.  Some welcome the change in seasons, but I much prefer summer.


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In the Grand Scheme of Things….

You have to wonder–what kind of guy would spend an inordinate amount of his time posting photographs of insects to the internet?  I don’t know.  Seems like an odd thing to do.

I just sat outside on my little patio and listened to the music of the cicadas.  And it gave me a tiny bit of pleasure.  And so do photos of the odd little things that run the world.  I check out Facebook pages that deal with insects.  Some specialize in robber flies, some in jewel beetles.  I check out one that deals with slime molds (absolutely amazing creatures if you look at them closely.)  I browse pages on native fishes and reptiles and amphibians.

I also look at pictures of babies, especially when I know or am part of the family.  I block a lot of political stuff though.

But I am going to post some pictures of a fly that I photographed this weekend.  Because it’s a cool fly.  I am not sure why I think it is so neat but I do.

This is a feather-legged fly, Trichopoda pennipes.  It is not particularly rare.  It belongs to the tachnid group, which typically have larvae that are internal parasitoids of other insects.  This particular fly lays eggs on true bugs, typically squash bugs.  The larva burrows into the insect, eating it from the inside out.  It is a parasitoid rather than a parasite because it kills its host.

Glad I could bring a little bit of insignificant information into your life.

You’re welcome.


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Late Summer Prairie Walk

I went on a nature walk today, organized by the Iowa Prairie Network, at the property of Bill and Sibylla Brown.  They have land in southern Iowa, and have done a lot of work to restore the biological function of the prairie and especially the savanna on their property.  People who track biological diversity in Iowa have been amazed at the species they have documented.  Many species of rare butterflies, rare fungi, and other creatures have been found on the property.

The flying insects stayed hidden early with the cool wet weather, but came out later when the sun came out.  This is the common eastern bumblebee, Bombus impatiens.

This eastern tailed-blue was on a grassy path in the prairie.

There was a nice gray hairstreak on the rough blazing star.

This was a colorful syrphid fly.  I don’t think I have seen this one before.

It was a pleasant morning.  It is great to see people managing property for biological diversity.


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Cool Fly

Some sort of dance fly.

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A Few Late Season Insects

We have had some strange weather lately.  Cloudy with light mist, followed by intense rain, then sunny, hot, and humid.  In between the rain, lots of insects come out and visit flowers or chase their prey.

This bumblebee, Bombus impatiens  was on sedum right outside my apartment.

This one was on a thistle near Big Creek Lake.

This is a familiar bluet, Enallagma civile.

This is a syrphid fly, probably in genus Toxomerus.

Another syrphid, Syritta pipiens.

Finally the least skippers, Ancyloxphs numitor, were quite busy on the fog fruit.

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On Bugshot Alabama

I just got back from a macro photography workshop called Bugshot Alabama.  These workshops have been going on for several years and are named after their locations–typically some place with high biological diversity.

This is from the outside a pretty nerdy thing to do.

So we spent a lot of time playing around with expensive camera equipment, plus lots of cobbled together equipment designed to create special light or conditions to show insects at their awesome best.   There are neat little tricks that are not always obvious and are fun to know.

I started thinking about why I was there and came up with a little bit of an analogy.  Suppose you are a musician.  You play guitar in a local band.  You spend a lot of time and effort at it, and you are really good at it.  But you get a chance to jam with some famous musicians–let’s say Eric Clapton, Bruce Springsteen, and some others of similar skill.  Wouldn’t you jump at the chance?

I’ve been taking closeup photos for decades.  My experience goes back to when Kodachrome 64 was the best film to use.  I have reversing rings, bellows, extension tubes, and macro lenses for the “universal screw mount.”  I have other equipment I have purchased through the years and the progression of photography.

Most of the pictures I take are closeups.  I take terrible photos of people, but good pictures of bugs and other little things.  And I am pretty good at it.

But I am not Eric Clapton good.  I am not Piotr Naskrecki, John Abbott, or Jena Johnson good.

There were some natural history talks, and I came to another realization.  Not only are these folks world class macro photographers, they are also world class scientists and naturalists.

I enjoyed mixing with the other participants, all of us looking for that special shot.

I found this little syrphid fly visiting some small flowers near the woodlands.

This bee fly was in the short grasses near one of the machine buildings.

I loved the event.  I will do it again as time and finances allow.

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