Deep stack of live woolly aphid

[rjlittlefield]

I thought some of you might be interested in this little escapade.

Where I live some of the aphids have a fall form that's very fuzzy. I have no idea why -- something to do with dispersal and hibernation I suppose. Anyway, I was out picking beans this afternoon and saw one sitting quietly on a leaf about eye level. I thought it was kind of interesting and I wanted to photograph something, so I cut off the leaf and brought it and the aphid inside to see if I could make a deep stack.

First, we have the result. Yes, it's very messy. These aphids are like that. 49 frames using a Nikon CF E 4X objective. More in a moment about how the stack was shot.



Just to get some kind of comparison for the stack, I also shot a few frames at lower magnification and stopped down to something like effective f/50 for DOF. Here is one of those images, cropped to see as much detail as there is in the image. It's not very much. Sorry about the blur -- it's just the perils of stopping down and all that.



All of the above is pretty routine.

Now here's where things start to get more interesting.

This is, of course, a live aphid. And while these aphids are sometimes willing to sit in one place for quite a while, that doesn't necessarily mean they sit completely quiet. Here are a couple of frames that show the problem. These were not from a stack, just singles with a few seconds in between. Suffice to say that blasting a flash in the critter's face was not a calming influence.



So, what I needed to do was to shoot a stack quickly, using continuous illumination. Fortunately, cameras have now evolved enough to grab decent high res video. My plan was simple: mount the camera on a StackShot rail, put the camera into video mode, turn it on, and run the rail back and forth a few times until I happened to catch the critter completely at rest for a couple of seconds. What could possibly go wrong?

I learned what could possibly go wrong as soon as I pushed the button on the StackShot controller. With the rail fastened firmly down, my stacking frame makes a pretty good sounding board. I'm guessing that the vibration pattern of a StackShot motor at the speed needed for this stack is some kind of match to a natural enemy of aphids. In any event, the resulting behavior of the aphid was not exactly conducive to stacking.

What to do, what to do?? I really wanted a stack of that aphid, so I was willing to try pretty much anything.

Well, from previous work with the StackShot using Live View and 10X objectives, I knew that while the rail makes quite a bit of noise, it doesn't actually make much vibration as seen by the camera. So I thought I try something a bit off the wall and just isolate the rail from the rest of the stacking jig. One minor modification to the setup, suddenly the rail got a whole lot quieter, the aphid got calm again, and I got my stack!

Here's the modification.



Yep, you're probably seeing it correctly. I just had to photograph this for posterity. One StackShot rail with camera attached, sitting calmly on a folded dishtowel, not fastened to anything at all, staring into the side of a live aphid on a bean leaf. Looks crazy, worked fine. (I'm thinking I should at least order some Sorbothane. The towel thing is a little too informal even for me.)

Camera: Canon T1i.
Objective: Nikon CF E 4X NA 0.1, 160/- on 165 mm total extension.
Rail speed: 0.4 mm per second (20 µm per frame at 20 fps).
Total acquisition time, 45 seconds at 1920x1080.
Acquisition time used in final stack, 2.5 seconds.
Conversion from .MOV to .jpg sequence by QuickTime Player Pro.
Processing by Zerene Stacker, mostly PMax with retouching from DMap.

Hope you find this interesting!

--Rik

PS. The aphid was returned safely to its bean plant. May it go in peace...

Edit: in the title, replace "fuzzy" with "woolly".

[Craig Gerard]

Rik,

The question I originally posted is no-longer relevant...so I have edited my post.

Craig

[LordV]

Like the dish towel mod.
The aphid is i think just an adult winged form of the wooly aphids you get.
Brian v.

[rjlittlefield]

The aphid is i think just an adult winged form of the wooly aphids you get.

I think you're right. I retrieved the beast and popped it under a dissecting scope to take a closer look interactively. No sign of cornicles, and the fuzzy stuff looks like waxy exudate. I've never noticed these beasts except this time of year. Now they are very obvious, but I have no idea what is their host the rest of the year. I'll ask one of the local entomologists.

--Rik

[rjlittlefield]

Did you notice much movement (subject shift, not initiated by the aphid) between slices?

Looking at the ZS project file, there's about 6 pixels of horizontal shift from one end of the stack to the other. The shift between adjacent frames is a fraction of a pixel. If I turn off X- and Y-shifts and flash between the outputs, then there are obvious differences in the geometry but I'm hard-pressed to say that one is better than the other. I can't tell whether we're looking at a real physical shift of the camera or a bogus shift due to the appearance of OOF image areas. It does seem clear that there is no short-term jitter of the rail over this 1 mm of travel, if that's what you were interested in.

--Rik

[LordV]

The aphid is i think just an adult winged form of the wooly aphids you get.

I think you're right. I retrieved the beast and popped it under a dissecting scope to take a closer look interactively. No sign of cornicles, and the fuzzy stuff looks like waxy exudate. I've never noticed these beasts except this time of year. Now they are very obvious, but I have no idea what is their host the rest of the year. I'll ask one of the local entomologists.

--Rik

Often found on fruit trees - either leaves or twigs as fluffy masses. Think the Autumn sexually mature adults are just more easily seen as individuals.
Brian v.

[Craig Gerard]

Rik,

I am currently working with a StackShot (as I write), hence my impulse question. I'm using the StackShot as a subject mover in a vertical configeration with a 10X MO on the 50D, looking for 'shifts' whilst quickly alternating between the 'Fwd' and 'Back' button on the controller. Have also compared aligned ('view adjusted') and non-aligned images in Zerene by scrolling through the input images....looks okay; but I'm still looking.....

Craig

[DaveW]

Interesting Rik. Being a Cactophile I am used to mealy bugs, including root mealies, but thought only the males had wings in these type of creatures. Evidently Woolly Aphids are different since I found this on the Web:-

"Woolly aphids generally have two hosts: a primary host on which they overwinter, and a secondary host on which they spend much of the summer. Most woolly aphids share a similar life cycle, although some details of the life cycle may vary among species. They usually overwinter as eggs laid in bark of their primary host. In spring, the eggs hatch into females which give birth without mating. Each female can produce hundreds of offspring, so populations can grow rapidly.

After one or two generations on the primary host, winged females are produced, and they fly to secondary hosts. They remain on secondary hosts for the remainder of the summer, producing several generations of young aphids. In late summer or early fall, a different group of winged females flies back to a primary host where they give birth to tiny male and female aphids that mate. Gravid females deposit a single large egg (or eggs) into protected locations in the bark and then die. While woolly aphids generally have two hosts, many species can sustain themselves on their secondary host alone."

Interestingly some generations lay eggs whilst others give birth to live offspring:-

http://www.reference.com/browse/aphid

DaveW

[rjlittlefield]

looking for 'shifts' whilst quickly alternating between the 'Fwd' and 'Back' button on the controller.

My unit has obvious shifts at high mag when reversing directions. This is to be expected because any difference in friction on the two polished guide rails will cause a bit of rotation in the carriage between sliding forward and sliding backward. This is a form of backlash. It is described in detail in many articles about linear slides, because it limits repeatability in systems that must reverse while operating or have guides that are prone to stick-release at different times. After reversing, once the slack has been taken out and the carriage has assumed a new stable position, then the StackShot motion is quite smooth.

My behemoth slide table has the same behavior, except that with it, for precision work I can preload the table with bungie cords to keep the slack removed so that even reversals are smooth.

--Rik

[Harold Gough]

Often found on fruit trees - either leaves or twigs as fluffy masses.

Often found on apple trees, also on beech trees.

http://homepage.eircom.net/~hedgerow14/june02.htm

Harold

[NikonUser]

This looks identical to the adelgid we get here in the east and flies in large numbers in early October.
They are considered to be forest pests of evergreen softwoods such as fir, spruce, hemlock. Not sure if they attack harwoods in the east, maybe in the west where Rik lives.

[rjlittlefield]

Thanks for the comments, everybody.

My contact at the local university writes that:

Well, not that easy Rik!

Its certainly a woolly aphid as you guessed but which species? There are lots of them but the sp we most often see around here is woolly apple aphid..sometimes a serious pest of apples. They spend summer on apple trees but migrate in autumn to other hosts including elm, hawthorn, ash and cotoneaster. Winter is spent on the roots of these plants (sometimes apple tree roots). So I'm guessing your aphid was en route to an overwintering spot... do you have an apple tree nearby?

As it happens, I live in a residential area where there is probably one of everything in somebody's backyard nearby. So let's give it a "maybe" on woolly apple aphid, but I think we'll never nail this one down for sure.

--Rik

[seta666]

I find it is very interesting way of stacking live subjects; the 500$ stackshot looks awesome on top of the dish towel ;-)
Regards

[Harold Gough]

Interesting Rik. Being a Cactophile I am used to mealy bugs, including root mealies, but thought only the males had wings in these type of creatures. Evidently Woolly Aphids are different since I found this on the Web:-

"Woolly aphids generally have two hosts: a primary host on which they overwinter, and a secondary host on which they spend much of the summer. Most woolly aphids share a similar life cycle, although some details of the life cycle may vary among species. They usually overwinter as eggs laid in bark of their primary host. In spring, the eggs hatch into females which give birth without mating. Each female can produce hundreds of offspring, so populations can grow rapidly.

After one or two generations on the primary host, winged females are produced, and they fly to secondary hosts. They remain on secondary hosts for the remainder of the summer, producing several generations of young aphids. In late summer or early fall, a different group of winged females flies back to a primary host where they give birth to tiny male and female aphids that mate. Gravid females deposit a single large egg (or eggs) into protected locations in the bark and then die. While woolly aphids generally have two hosts, many species can sustain themselves on their secondary host alone."

Interestingly some generations lay eggs whilst others give birth to live offspring:-

http://www.reference.com/browse/aphid

Dave,

The classic is the black bean aphid (a black aphid of beans, not an aphid of the oriental black bean ) Aphis fabae*. It* spends the winter on the spindle tree, where the sexual part of the life cycle occurs, moving to beans in summer. This species is the example always quoted in school biology syllabuses.

http://www.arkive.org/black-bean-aphid/ ... xt=Biology

* There is a complex of species. I don't know how far this has now been sorted out.

Harold