Whenever I'm asked which of my own photographs I like most, I think of Woody Allen admitting he never watches his movies: no matter how good the work, the impulse is strong to notice faults and give the subject another try.
In general, though, I feel the most delight with the rare image that captures a whole story -- a photograph that is indeed worth a thousand words. Like the well-wrought essay, nothing in such an image should be wasted: the eye should be able to linger anywhere within its borders and be rewarded with something relevant to the story.
I learned my philosophy from Mary G. Smith, the science editor at National Geographic who got me started at the magazine. I was working on an article we called "Life in a Nutshell," about the menagerie of species that invade acorns. Most of the story happens after the acorns fall to the ground; for example, the slavemaking ants described on pages 151-153 of AAA often use multiple fallen acorns as apartment homes for their expanding colonies.
A set of images for any story should make even obvious relationships clear. As I worked on my acorn shoot, one basic thing I missed was the fact that acorns come from oaks. Mary wanted me to come up with an unusual "take" on this relationship between nut and tree: Could I get her an image with an acorn on the ground and an oak tree and a bird flying off carrying another acorn in its beak... and how about a rainbow for good measure, so the text could describe the weather conditions suited to developing acorns?
I ended up on my stomach with a wide angle lens aimed up at an oak in Harvard Yard, lying so still for hours that the campus police were called on the suspicion I had passed out on the grass. I don't think the result is my best picture. I certainly didn't get all the elements Mary had mentioned into the frame. But it did add enough to the story to serve as its lead image.
At least two images in AAA come closer than my oak picture to this idea of a ideal image. There's the one on page 43 (upper image below) that shows a 3 millimeter guard worker of a "trapjaw ant" using her long trap-like mandibles to drive off an intruder from the entryway to her nest. Behind her a larva eats this species' typical prey: a speedy rabbit-like invertebrate called a springtail that bounces around using its long tail (here hanging limply forward). The jumps makes springtails virtually impossible to catch unless the predator has a trap for jaws.
Then there's the photograph on page 69 (lower image below), which shows the special jobs performed by three of the four types of workers in the army ant species Eciton burchellii: at left, a "submajor" worker hefts a chunk of prey while the smaller "media" worker behind her serves to lift the booty's dragging end; hidden below them and smaller still, a "minor" worker lies in a pothole along their path, acting in effect as "living roadfill."