Diptera or Hymenoptera? A Little Insect ID

Remember this picture from June 26?

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bee on swamp milkweed (Asclepias incarnata)

A reader commented that it might not be a bumblebee – might not even be in the order Hymenoptera.  These things bug me, so I did a little research.

First, a quick summary of taxonomy: species of organisms are grouped into genera, which are grouped into families, which are grouped into orders, which are grouped into classes, which are grouped into phyla (for animals) or divisions (for plants), which are grouped into kingdoms, which are grouped into domains. (If you’re my age, you learned as a child that all life is in either the plant or animal kingdoms, a notion that was actually discarded before I was born, but I’m not going to sidetrack into the history of taxonomy; let’s just say that classification systems change as scientists learn more.)

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bee on narrow-leaved mountain mint (Pycnanthemum tenuifolium)

There are 30 or so orders within the class Insecta (those wacky taxonomists are always redefining things, so it’s hard to say exactly how many).  One of these is Diptera, which comprises mosquitoes and flies.  Another is Hymenoptera, which comprises bees and wasps.

At this point, you night be wondering, isn’t the creature pictured obviously a bee? Not necessarily.  There are flies, like this one, and for that matter moths, like this one (yet another order, Lepidoptera), that look, superficially at least, a lot like bumblebees. Beespotter.org has a page about bee mimics; it’s an interesting read.

The commenter on my blog pointed out that the insect in question appears to have only two wings, which suggests Diptera.  (That’s what “diptera” means: two wings.  Insects in the Hymenoptera have four wings.)

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bee coming in for a landing on basil balm (Monarda clinopodia)

After more hours than I care to admit reading field guides and surfing the internet, I was still at a loss to say what this creature is, mostly because I couldn’t tell from the picture if it has two wings or four.  So I asked the expert: a friend who is an entomologist.  I emailed him the picture with the note “What order is this in? I’m not even going to say what my thinking is here”.  Here’s his reply:

“Hymenoptera. I know you are thinking Diptera, because it looks like it only has one pair of wings, but it actually has 2 pair. Hymenoptera have a series of “hooks” on the trailing edge of the front wing called hamuli, and these serve to link the wings together. You can actually see the two wings in this picture – the notch near the bottom of the “wing” is the demarcation of where the two wings join together. A give away in this photo that this is a bee and not a fly are the antennae, which are long and multi-segmented. Flies have shorter antennae, with fewer segments.”

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a brief pause on the morning rounds

So, it’s a bee: class Insecta, order Hymenoptera, family Apidae, genus Bombus.

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Bombus (probably) departing Monarda, en route to Erigeron

3 thoughts on “Diptera or Hymenoptera? A Little Insect ID

  1. Elizabeth, if you haven’t already checked out Flower Flies (also called Hover Flies), they’re in the Order Diptera, Family Syrphidae, another group of Bee mimics. If you want some help in identifying Bumble Bees, there are several color flyers available as documents at Xerces (http://www.xerces.org/). Also Bumble Bees can be confused with Large Carpenter Bees (I think they’re in the Genus Xylocopa). Large Carpenter Bees have hairless abdomens.

  2. Pingback: Garden Phlox, with Very Special Guest: A Bee Mimic! | Elizabeth's Wildflower Blog

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