August 16th, 2006
a small mystery
Today, I’ve got quite a lot on the go, so this will be a shorter post than usual. I’m hoping to spend much of today out photographing insects as the weather seems near perfect *AND* I have the “I and the Bird” carnival to put together so that it can appear *here* tomorrow! (Yikes!! I feel like I have too many things on the go, but I’m sure I’ll get everything finished tonight!!).
Anyhow, this morning, rather than posting something informative, I’ve decided to post about a small mystery that I’m just beginning to puzzle over. I welcome all armchair detectives to post your IDs, comments about what you believe to be going on in the above photo, etc… (click on both photos for a larger view).
Here are a few details and a couple of my own “guesses” as to what might be going on.
While out for a hike on Saturday, I found these two flies on a plant. As can be seen in the above photo, one of them seems to be staring at a weird white, columnar-shaped blob on a leaf. The other fly is sitting close by. Neither of these flies was at all interested in moving when I shot these photos. They seemed quite determined to stay right in place. Here’s a rather poor but closer view of the white blob and one of the flies. I don’t think the strand of web nearby has anything to do with these flies. Off hand, my guess is that the white blob may be the eggs of these flies and that one, or perhaps both, are exhibiting some form of egg-guarding behaviour — but I could be entirely wrong. Perhaps this is some Fly-God Shrine and the flies are gathering to worship. Or, the blob is something delectable that they’re planning to eat. Comments are invited.
Regarding the ID of the fly, below is a better shot of one of the flies. What is most conspicuous about these flies when seen from a couple of feet or so away is the very black, rounded wings. They remind me of Mickey Mouse ears. I haven’t even begun to start working on an ID for these, so if anyone wants to take a stab at it, please be my guest — although don’t feel obliged to spend too long working on it!
Okay, I’m out of here to enjoy some sunshine and shoot some insect photos.
Tags: mystery fly
August 16th, 2006 at 2:20 pm
I have absolutely no idea, but I am leaning toward the Fly-God shrine as the answer. It’s an interesting mystery.
August 17th, 2006 at 1:18 am
Robin – At this point, the Fly-God shrine seems like as good a theory as any!
August 17th, 2006 at 9:08 am
Difficult i.d., Bev. I’m pretty sure it’s an acalypterate fly, but I’d have to be able to see the bristles on the face, antennae, and back, and the wing venation, to be able to put it in a Family. I’m guessing something in Sciomyzoidea, but could be well off the mark. An entomologist at a major museum or university in your region would probably be able to recognise it immediately, with such distinctive wings. I’d be surprised if the shrine was an egg mass, but that being said, I have a good capacity for being surprised.
Sorry I can’t be of more help.
August 17th, 2006 at 11:49 am
Pete – Thanks for taking a look at this fly and offering some info on the possible ID. I’ll probably send the photos along to an entomologist from this region who specializes in diptera. Usually I work on the ID for a bit before I resort to bothering someone! (-:
August 18th, 2006 at 5:27 pm
A friend and I saw a very similar species yesterday on common milkweed, she id’d it as genus Eutreta [link].
Those wings certainly are distinctive.
August 18th, 2006 at 6:24 pm
Jenn – Thanks for posting the link.. that does look pretty much the same.
March 29th, 2007 at 9:03 am
The blob is secreted by the male to attract the female. The female feeds on the mass during and after the male mates with her. I hope this helps.
March 29th, 2007 at 9:27 am
Matt – Thanks very much! It seemed that the blob must be of some significance, and indeed it is!