Aphid predator: fly larva

rjlittlefield · Post by **rjlittlefield** » Sun Jun 03, 2007 5:18 pm

This one's new to me. When I just glanced at the predator, I thought it was a small aphid lion (lacewing larva). But on closer inspection, that wasn't even close! What we actually have here, I believe, is some kind of fly larva.

A quick Google image search on aphid predators got lucky. Hit #1 looks quite similar to this beast, and guess what -- it's called an "Aphid Predator".

The commercial Aphid Predator is Aphidoletes aphidimyza, a small fly in the family Cecidomyiidae, the Gall Midges. They're called that because most species cause plant galls. But not so with Aphidoletes -- its larvae are active predators of aphids. Another fascinating feature of the group is that "Larvae of some gall midges produce daughter larvae (paedogenesis) for several generations." (Bland, How to Know the Insects, 3rd Edition, pg.333).

I rather doubt that what's shown here is exactly Aphidoletes aphidimyza, and it might not even be a gall midge. But these names are certainly handy for looking up some interesting biology!

--Rik

Technical: Canon 300D, Sigma 105mm macro at 1:1 and marked f/16. ISO 100, electronic flash. Hand held, well braced on countertop. These are about 67x39% of full frame (1376x1202 from a 2048x3072 frame).

Ken Ramos · Post by **Ken Ramos** » Sun Jun 03, 2007 5:34 pm

Ha! I love these photos Rik

. Look at all the little aphids and the details of the entire scene. Wonderful! Reminds me of the work of Hieronymous Bosch

Bruce Williams · Post by **Bruce Williams** » Sun Jun 03, 2007 5:35 pm

Really interesting post Rik. Nice clean images with excellent lighting (now you're gonna tell me it was the kitchen window

). Aphids show an interesting diversity in size and colour too - don't you think.

Bruce

Ooops- just picked up on your technical note showing light source as electronic flash

rjlittlefield · Post by **rjlittlefield** » Sun Jun 03, 2007 6:03 pm

Glad you like 'em, guys!

Bruce Williams wrote:...just picked up on your technical note showing light source as electronic flash

To add a bit of detail about that...

My use of flash with macro often resembles a juggling act. I have a small, ancient, Pentax flash unit that I run in plain old manual mode on the end of an equally ancient home-made cable, and I hand-hold it at the front of the lens in whatever position seems most likely to cast shadows where I want them. If I want more diffuse light, sometimes I wrap a handkerchief or paper towel around the flash and hand-hold the whole mess. Elegant, it's not. If I saw somebody else doing it, I'd probably laugh and shake my head. But it works OK, and the whole lighting system fits nicely into a ziplock sandwich bag. Tradeoffs, tradeoffs...

Yes, aphids are fascinating critters. I did not appreciate how much variation they have within a single population, until I started shooting them in macro. This old post is still one of my favorites.

--Rik

PS. The plant is a rose.

rjlittlefield · Post by **rjlittlefield** » Sun Jun 03, 2007 6:40 pm

I took some more shots from a different angle. Here is a good one:

This shot clearly shows that the critter has two of those tail-like extensions. In this view, it also looks like the filmy thing seen under* the fly larva in the first picture may be a recently shed skin. At least it's about the right size, shape, and consistency.

[*] In this picture, it's about one fly-larva length above the fly larva.

--Rik

Edit: change external link (url tag) into an inline image (img tag)

Ken Ramos · Post by **Ken Ramos** » Sun Jun 03, 2007 6:47 pm

You know its funny with these little things. Even with a predator among them, they go on about their daily business of sucking up plant juices and spreading viruses, ignoring or dismissing the danger in their presence.

rjlittlefield · Post by **rjlittlefield** » Sun Jun 03, 2007 6:56 pm

Yes, they seem completely oblivious to this fly larva.

http://www.omafra.gov.on.ca/english/cro ... aphids.htm mentions that:

A further positive characteristic of Aphidoletes is that unlike parasitoids, it causes little disturbance in colonies. Because of its furtive behaviour, it triggers little defensive reaction by aphids. This means that aphids attacked by Aphidoletes are less likely to disperse, escape predation, and start new colonies. When aphids are attacked by parasitoids, they defend themselves by kicking and producing alarm pheromones (chemicals used for communication within a species), resulting in their own escape, as well as many other members of their colony.

--Rik

Charles Krebs · Post by **Charles Krebs** » Sun Jun 03, 2007 7:11 pm

Rik, this looks like the the same critter I found last year in June (posted a few shots in the old forum... if some more views would be helpful). At that time I was also amazed at how little attention it garnered... other aphids would climb right over it... even while it sucked one of their little buddies dry!

rjlittlefield · Post by **rjlittlefield** » Sun Jun 03, 2007 7:45 pm

Charlie,

Ah yes! http://www.photomacrography1.net/forum/ ... php?t=5187

Wonderful images, which I confess I had completely forgotten about.

These things do seem quite similar, though obviously not identical.

--Rik

rjlittlefield · Post by **rjlittlefield** » Sun Jun 03, 2007 10:29 pm

Ken Ramos wrote:Look at all the little aphids and the details of the entire scene. Wonderful!

Ken, I'm really glad you liked all these details. It turned out that I had to go to some considerable trouble to get so many of them clear in these images.

The stem that the aphids are on is basically straight. So is the leaf coming off it, that the predator is on. Two straight lines that intersect, form a plane, so clearly, all I needed to do was to get that plane parallel to my camera's sensor, and everything would be in best possible focus.

An admirable theory. And it worked OK in practice too...after I clipped away a large flower and another separate stalk that intruded into the line of sight that I needed.

By the time it was all over, I felt like I needed to put on one of Mike Broderick's disclaimers: "controlled situation".

But I didn't...perhaps because I felt like the subjects were still more in control of the situation than I was.

--Rik

Gordon C. Snelling · Post by **Gordon C. Snelling** » Mon Jun 04, 2007 4:15 pm

Looks like a Syrphid larvae.

beetleman · Post by **beetleman** » Mon Jun 04, 2007 4:37 pm

Amazing photos Rik. An excellent find.

rjlittlefield · Post by **rjlittlefield** » Mon Jun 04, 2007 10:33 pm

Gordon C. Snelling wrote:Looks like a Syrphid larvae.

That would certainly make sense, but I'm clueless about how to tell the difference between Syrphid and pretty much any other fly larva. In fact my copy of How to Know the Immature Insects (H.F.Chu, 1st edition, 1949) just bundles the whole suborder Cyclorrhapha as "Key to families is not available".

Are you looking at something in particular as distinguishing features, or is this one of those "general appearance" things?

--Rik

Gordon C. Snelling · Post by **Gordon C. Snelling** » Tue Jun 05, 2007 5:32 am

Pretty much just general appearance based on the numbers of Syrphid larvae I have seen around here. However I could still be wrong, Im not much of a fly taxonomist, my specialty being ants.

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Tue Jun 05, 2007 7:50 am

Very cool, without knowing, you could have convinced me this was some sort of slug!