Assisting Science

Potomac Review 37 (spring/summer 2004): 90.

The use of Latin terms, my biologist husband has clarified for me, is not to sound smart but to avoid confusing different organisms, because in some cases the common name is applied to several species. Take your basic tomato hornworm, whose name is used for different species of caterpillar. But apply Latin binomials, and, voilà, we have names to distinguish them.

A few summers ago Brian conducted research that involved Hamamelis virginiana, or witch hazel, and Hormaphis hamamelidis, the gall aphid. These particular galls are huts that the insects build on leaves for raising their babies. You can’t even see the aphids without a microscope; the first time Brian showed me one, I stared at a lovely leaf upon which nothing crawled. “What am I looking at?” I huffed.

“First of all, you have to be patient,” Brian cautioned, well aware this was not my strong suit. He handed me a portable field microscope with built-in light, and showed me how to press the illuminating button while holding the tool so close that it all but pressed against the area of scrutiny. I practiced on my own finger, marveling at the lines of ditches that once had been fingerprints, a small universe magnified. Now expert at manipulating the technology, I turned back to the leaf where Brian’s enormous fingernail pointed. “There it is! I see it now!” I was actually excited about discovering this brown six-legged tank that I hadn’t been able to spot with my naked eye.

Many types of aphid—rose, pea, sycamore, peach-potato, and others that feed on trees, shrubs, grass—are considered pests. If you’ve ever parked your car under a shade tree and found it covered in sticky transparent frosting dotted with infinitesimal black spots, you may have experienced aphid poop. To other living things their excrement, gummy because of the leaf-sap diet, is ambrosia.

Ants love it. In a banquet of recycling, the waste matter, brimming with tree juices and sweetened by the aphids’ digestion, becomes precious nutrition for ants raising their brood. They actually tend aphids to harvest their offal, which they drink up and, back home in their own nests, vomit. They feed their grub-like larvae by regurgitation, like birds.

The witch-hazel cone-gall aphids of Brian’s fascination house their population using the available materials in their microscopic domain: the leaves that sustain them by interacting with the secretions of their own bodies. They stick in their syringe-type mouth parts, called stylets, and the leaf, irritated by this intrusion it is powerless to prevent, reacts by forming a protective shell around the bruised area: the gall. Conveniently for the mother, this grows around her and her offspring, and here they all flourish on leaf juice.

So by wounding the plant and causing this reaction, the insect has, amazingly, manipulated it into building her home. The red, pointed gall protects the creatures from most predators—at least until we got here. Only humans can penetrate it with ease. Even birds have to work at getting in there, pecking through the armor of hardened leaf. Among the beaks that probe are those of black-capped chickadees and pileated woodpeckers, which drill into the nuggets of nectar and protein and polish off entire families.

That summer, Brian wanted to observe these Lilliputian critters that “specialize” in witch-hazel juice. He wanted to study the effect that aphid galls have on the trees, and vice-versa. To study the insects and their nesting habits, Brian had a full field season planned. He would measure leaves and galls on 23 trees, then collect from about half of those (which meant at least 200 galls). Two-week breaks would be filled with chemical analyses in the lab and inputting numbers into a computer program that would statistically analyze the data. Comparisons of sizes and positions on leaves should yield clues to the puzzle he sought to resolve: Where and why did aphids build?

The scientist would need an assistant at each stage, and I feared this could be me. I’d heard much about the drudgery of fieldwork and had been grateful for the undergraduate assistants who usually fulfilled such tasks for hire, but apparently there was a shortage of them that summer. Though I had work of my own to do, I did want to understand the reasons for my husband’s inquiries. I had no plans to enroll in any science courses but wanted to grasp the layman’s version, to see for myself why it was important. I volunteered to fill in.

The witch hazel is an elegant small tree with spindly branches that twist from a slender trunk, often curved over like an old woman’s backbone. Its foliage spreads little leafy roofs four to six feet high in the lower forest. In the almond-shaped leaves, veins run pinnately off a central axis.

There’s medicine in the graceful bush, such as its ability to soothe minor skin irritations. The leaf chemicals draw things together and close them up, making it an astringent. Native Americans collected witch-hazel leaves, dried and powdered them to treat wounds. Today the plant is under investigation for antiviral and antibacterial properties as well.

Maybe it grows magic. Etymologically the name evolved from the Old English wican, “yield,” into the sixteenth-century term for a tree of pliant branches, witch. North American settlers used the supple limbs to sniff out water sources underground, leading to otherworldly speculations. The tree even looks witchy, especially against a full cold moon on a winter night, when its bare, tangled branches reach out as a resting place for flying spirits.

Autumnal wizardry makes fruit and flowers appear simultaneously, unlike on most trees. Hamamelis means “same fruit,” naming a process in which last year’s flowers become this year’s seedpods. Tender green capsules that have pushed up all summer beneath dried-out blossoms disperse in the fall. Meanwhile, yellow petals nearby start the cycle anew. Bugs (technically the incorrect term, of course) crawl and fly about, which brings us back to Brian’s interest: ecological interactions.

He wore khakis and a green T-shirt; my outfit was similarly earth-toned. I’d learned during our woodsy explorations that not only wasps, but many insects are attracted to the turquoises, purples, reds, and blues that I’d once favored. In the Southwest, electric blue signals to the horsefly a veritable revelry.

My job was to record the measurements Brian called out. I wrote on page after page of hand-drawn columns, balancing on my lap an 8½-by-11-inch pad of lined paper clipped onto a field desk. This was an aluminum box with a metal-clipboard lid, very effective for outside work. The bark of my “seat” dug into my flesh. I resolved to bring a beach chair next time.

Brian had wandered through the woods a few days ago assigning numbers to the pieces of nature he wished to study. He had picked and tagged trees—1001, 1002 for his first study site, 2001, 2002 for the second, and so on for a total of three sites where he would measure and take samples. Then he’d gone back through the whole range to select specific twigs and number those as well, 1 through 20-plus on each tree. He’d Magic-Markered each digit onto orange flagging tape that we would remove in the fall.

He’d entered the number of each tagged tree and leaf into his field notebook, and now, out here with me as his assistant, all he had to do was call the preassigned digits and then the dimensions for leaves and galls. He held a ruler against each leaf and then calipers against each gall. As I recorded, I reminded him if he forgot to say the identifying part, without which the measurements that followed related to nothing and the data were worthless.

I was somewhat annoyed with myself, at first, for having offered so readily to do this boring job. Still, it was obvious that Brian could move through the forest relatively fast with another human in his wake; a tape recorder would only slow him down. And I knew that he really did need all these numbers. Tedious though the process is, it is the accumulation of “raw data” that allows researchers to draw conclusions. Every chart and graph contributes to the ongoing quest to unravel the mysteries of our planet.

Of course no one cared here, aside from the two of us. Certainly not the aphids, many of whose homes were destroyed in the process of becoming raw data. The leaves did not care, nor did the trees, nor a single one of the ovenbirds that hopped and sang about the forest floor. The orange-capped, spotted-tummy warblers could not have cared less, nor could any of the owls, grouse, or tanagers that Brian said were out here somewhere.

Rabbits, deer, foxes, worms, flies, bear—not one element of nature was interested in Brian’s studies apart from us. We humans are the only ones who feel this need to dissect, examine, discover a big picture. Everyone else just lives and dies without disturbing the beautiful balance of it all, which out in the woods is easy to appreciate.

Rothrock State Forest, just outside of State College, Pennsylvania, is hundreds of acres of rough topography cloaked in greenery. A stream runs by the road, green and clear, over the rocks of limestone and basalt that are the foundation of this land. Only an occasional motor vehicle spurts its poisons at the white pines and hemlocks that abut the pavement.

Uphill in Brian’s field site, amid oaks and mountain laurel and witch hazel, the sounds of civilization were muffled. Breezes swished through early spring growth, hawks screeched, downy woodpeckers sailed to their next booty. Our own noises were in the minority. Every time Brian moved from one leaf to the next, last year’s fallen leaves crinkled under his boots and released a powdery, desiccated smell. When we packed up the operation to haul it on to the next tree—lugging packs, field desk, water, paraphernalia that other beasts do not carry—-we filled the woods with our racket, our intrusion. Not that I harbor illusions about nature being gentle without us around.

I perched on a log that had succumbed, within a few years, to break down and join the squishy forest floor. “Lat 14, long 9, h 6.3, d 3.1,” Brian announced: the gall’s position on the leaf was at a latitude of 14 millimeters and longitude of 9; its height was 6.3 mm, and its diameter 3.1. I wrote it all down, about three columns’ worth. While I waited for the next set of numerals to come, I decorated page margins with space creatures and Arabian motifs.

Budding undergrowth rustled as Brian inspected the world, one gall at a time. Fieldwork is slow. But it does go faster once you stop worrying about that aspect and set your mind free.

Around noon we sat on a couple of lichen-decorated boulders near the stream. The earth smelled of ventilated rot, a wonderful dirt-basement sort of odor. Water trickled through the pines and sent up fresh wafts along with the melodies of its movement over rocks and roots. We’d brought peanut butter sandwiches, apples, and iced teas, an easy and quick field repast. Brian does not like to waste time on leisurely lunches. He happily accepts his place as a human—counting, diagramming, collecting pieces of nature that other animals see only as food or shelter.

Originally he had hoped to complete the survey in one day and envisioned it stretching out only if we’d been dropping with fatigue, dry-mouthed and in too much darkness to see. By lunchtime he’d accepted that the process would probably take three days.

That night I barely stirred, my dreams filled with breezes. In the morning I felt like an aired-out closet. Back to the site for Day Two. I unfolded my beach chair and organized the field desk while Brian assessed. There were a few trees, such as this first one of the morning, that went quickly. Because they were so scrawny, the work he could do on them was limited and we were soon packing up again.

I remained seated while gathering the water bottle and other gear we’d strewn about. Brian stood watching me, trying to be patient with the unnecessarily luxurious chair: among scientists there is an unspoken agreement that working in the field should be uncomfortable. Finally he carried it for me—which was kind considering that he enjoys roughing it and believes that I should too.

We tramped to the next station, only twenty feet away, and established our new camp. These jaunts stretched my leg muscles, an aeration of not only the limbs but also of the brain after a half-hour or more on my derrière. I tried to get Brian to sit at regular intervals too, since foot exhaustion is a good bet in his line of work.

“Okay,” he growled after finally giving in and sitting for a bit, “the chair was not a bad idea.”

A minor victory, the celebration of which I kept to myself. He got up and I made ready to inscribe. The biologist crunched over to the witch hazel and scrutinized. Periodically he leaned close and steadied his little field microscope over a leaf, with his eyeball pressed to the glass. From the insect’s perspective it must have been terrifying. “Wow,” Brian marveled, “now that’s an interesting one.”

Witch-hazel galls come in variations of shape and size. Some are “gigantic” (14 mm high, 6 wide) and house probably 120 baby aphids; more typically they reach a height of 10 mm and a diameter of 3, room for sixty babies.

Size is of critical significance, Brian would find more than a year later. After a second field season confirmed his results, he determined that the most important “fecundity factor” is how well mom manipulates the plant: how big her gall is. The number of progeny is directly related to size, but location is also significant: most galls are on the lower half of the leaf. This probably is the best real-estate location for two reasons: it’s closest to the main pipeline of nutrients, and terrain is more stable near the leaf base. In the wind, an insect foundress will not get tossed around as much before the gall covers her safely up. But regardless of where the gall is formed, the more spacious her house, the more children she has. Strangely, as we overburden our house of Earth with too many of us, humans seem to adhere to the opposite principle.

We began again: “Lat 14, long 9.” A pause while he measured. “Leaf length 65, gall height 5.9, diameter 3.2.”

I recorded, illustrated the margins, recorded, made another line and headed another column with the tree’s number, 2003. Then one of my space creatures’ psychedelic antennae absorbed me so much that I neglected to write down the number of a leaf from which he’d already moved on, meaning it had no identifier and hence might as well not exist. We would either have to backtrack or ignore those measurements.


Tell him? Make up a figure? I had to decide right now, because he was between leaves.

“Ah, sweetie,” I said, and told him.

He hurried over. “Shush!” he held up his palm, a policeman stopping traffic. He snatched the desk and rushed back, examined leaves and verified dimensions. “Okay that’s it,” he said, “I got it. Why don’t you take a break?”

I felt as if I’d been fired from a volunteer job, not an uplifting sentiment. But he was right: a few moments of distance, some air between us, that was what we needed.

I could have gone for miles on the trail through Rothrock, an old deer path maybe, crossing glens and hillsides slippery with loose rock. Spots of magic startled me, glades where a maple grove enveloped me in a sphere of golden light. Hand-shaped leaves were young, tender and new, almost visibly growing. I breathed in and grew too.

A crow, iridescent in the dappled sunlight, hopped about pecking at the ground, then swooshed off blaming me. A sound of knocking echoed, and I followed it to a pileated woodpecker high on a black gum trunk. The red-feathered head jabbed away so relentlessly I was surprised the tiny brain did not scramble. I tried to find evidence of other creatures, pellets left by deer, the larger loaves of black bear and raccoons.

How did they see me? With fear, I hoped. “Humans are most definitely to be avoided,” I yelled into the flora. I walked amid this wilderness of which I was a part feeling that I was also its enemy, as were all people. Yet I was small and stupid here; absent some sort of crash course in hunting and gathering skills, I would be dead within a week. In the “civilized” environment I had learned to survive, though even there my comprehension was limited. Here, I was in awe.

We pulled off the road at eight on Morning Three, after another stellar night’s rest. Only Trees No. 3002 through 3008 were left to measure. I felt lighter, less the reluctant helper today, perhaps because we were almost finished. Plus there was the sheer beauty of our surroundings. My brain cells by now had been suffused with fresh air, expanding from my lungs into the bloodstream, into the reaches of my thoughts, the maze, my abstract perceptions.

I followed Brian up the hill, tripping on ubiquitous rocks and gravel. He crashed along like a bear. Ten minutes later I set up the chair next to an oak stump, our handy breakfast table. Here I placed the gourmet coffees for which I’d insisted we stop, along with the almond croissants and, of course, napkins.

“Better eat yours before the ants do,” I warned.

“Yeah yeah yeah,” he rattled, as he searched for tags and arranged for the chronicling to go smoothly. Ignoring the dismissive tone, I shifted my beach chair to face away, melding my spirit with the enchanted land in which I sat. The sun cast morning light that filtered through the canopy, big soft spotlights from another realm. Where our breakfast stump met the composted earth, leprechaun moss spread over little hillocks behind which fairies no doubt hid. Purple petals grew in tangles of stems and leaves; blueberries peeked from the thicket. If I lived here I would build my house of fieldstone and oak, but I would clear only enough land for the dwelling. I would live beneath the trees, underneath this diaphanous green roof along with everyone else.

A chipmunk streaked by, a glimpse of red fur and white stripes, commotion in the brush. Another rodent bounced after it. Their squeaks and tumbles echoed through the snappy air.

Brian’s hand appeared on my shoulder, warm. “Sounds like us,” he munched through his bite of croissant. I stroked his fingers as we chuckled, another echo.

We moved to our posts. He leaned for a quick kiss before traipsing off to his investigations. I watched the big legs advance, committed soldiers of science. Brian was so earnest, so dedicated in his struggle to understand it all.

“Hey, you’ve never seen the inside of a gall, have you,” he said, as if suddenly remembering that I wasn’t your normal field assistant. “Come take a look at this,” he coaxed.

I set down my field apparatus and watched him slice open a gall. He held it in his palm while I peered through the lens. Huddled under their roof, a cluster of tiny green babies sucked on green moisture. It was an enclosed world of succulence in there. Everything swelled with juice, with the fullness of beginning life.

“That’s sap from the leaf’s veins,” Brian explained.

“But now we’ve killed them,” I fretted.

“Don’t worry,” he said, “there’s plenty of ’em.”

“Just like humans,” I mused.

Watching the aphids move in their nutrient-saturated world of fresh, springtime growth, I was looking straight at a plane of life that most of my own species weren’t even aware existed, nor would most have cared how it worked or why. Yet somehow, this was related to us. We were connected to it as surely as I stood among these trees under a morning sun.

I returned to my station. Carefully I turned to a new sheet of paper and verified that the columns were correctly headed. Today, I just wanted to help Brian get it right.

“By the way,” he paused between leaves, “forgot to mention those undergrads are coming next week, and I’m down for one of them.”

“Great!” I said. But I noticed a whisper of regret  slipping through me all the same.

Annie Rehill is a freelance writer in the Annapolis area. She still assists with her husband’s fieldwork and has even ventured into the lab.