Insect Catch-Up

by Carl Strang

I consider photos to be an indispensible part of this blog. Blogs are based on writing, but in a visual medium like a computer screen, I believe images are needed as well. I try to get photos of everything new I encounter in the field, and edit and copy selected ones into a file I keep for the blog. They then are the basis for new posts. Sometimes there are orphan photos, ones which by themselves may not be enough for an entire entry. Today I want to clear out three such photos of insects. The first goes back to mid-June.

Unicorn clubtail on May’s Lake

I had been seeing a few jade clubtails at Mayslake Forest Preserve, perched on shore or occasionally on floating algae, but then on June 16 there was an odd-looking individual that clearly was a new species for the preserve list. The photo made clear that this was a unicorn clubtail, a species in the same genus as the jade clubtail, common in some places but not, in my experience at least, in DuPage County.

Reversed haploa, a member of the tiger moth family

This was a big year for reversed haploas. Usually I see 5 or so in a season, but I saw dozens at Mayslake in the first half of July.

Bombus pensylvanicus. I think.

There are two species of bumblebees in northern Illinois that are so similar I cannot distinguish them confidently. From what I have seen in internet sources, I am not alone in this. Both have large areas of black on the thorax and large areas of yellow on the abdomen. There are variations in “fur” color on the head and posterior thorax that bring enough overlap into the picture to confound the identification of individuals. As far as I can tell, it comes down to the color of the basal abdominal segments. Less black and more yellow indicates pensylvanicus, more black and less yellow indicates Bombus auricomus. In my limited experience, though, there appears to be another possible indicator. B. auricomus seem to be brighter, the yellow and black so sharp as to really stand out, while the colors are duller in pensylvanicus.

Here is an auricomus from an earlier year

If any readers can lend insight on this, I would appreciate a comment to that affect.

1 Comment

  1. Gary Clinkman said,

    September 17, 2011 at 10:17 pm

    I think you might be right with the color brightness. A week ago I saw
    a big new queen with more yellow and that would make it pennslyvanicus. It was paler and not real clear. It was very big though.
    In August I saw another huge queen that had more black and was
    more clear in color. I see both of these species when I am monitoring
    butterflies at Orland Grassland and Turtlehead Lake. I see at least
    two other species as well.

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