so many ways gypsy moths can differ,” he said finally. “But the number of ways that humans can differ is really, really huge. And especially in their behavior. Right. Which gets back to your question, which is, How much does it matter that humans are smart? And so, I guess I’m actually going to say that it matters a whole lot. Now that I stop to think about it carefully. I think it will matter a great deal.”
Then he took me into the basement of the building and gave me a glimpse of the experimental side of his work. He unlocked a door to what he called “the dirty room,” opened an incubator, took out a plastic container, and showed me gypsy moth caterpillars infected with NPV. I saw what it looks like to go splat on a leaf.
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Of the two giant elm trees that stood before my neighbor Susan’s house, only one remains. The other died about four years ago, senescent, drought stricken, and harried by aphids. A contract arborist came with his crew and his truck and took it down, limb by limb, section by section. That was a sad day for Susan—for me too, having lived in the shade of that majestic hardwood for almost three decades. Then even the stump, big enough to serve as a coffee table, vanished. It had been ground down with a stump grinder and covered with grass. The tree is now gone but not forgotten. The neighborhood is less graceful for its loss. But there was no choice.
The other big elm is still here, arching grandly over our little street. Circling the tree’s grayish brown bark, at waist level, is a stain—a dark band of discoloration, evidently indelible against weather and time, marking where it was defended with toxic goo against the tent caterpillars, twenty years ago. The caterpillars are long departed, just another outbreak population that crashed, but this mark is like their fossil record.
When I’m home in Montana, I walk past that tree every day. Usually I notice the dark band. Usually I remember the caterpillars, how they came in such numbers and then disappeared. Conditions had been good for them. But something happened. Maybe luck was the crucial element. Maybe circumstance. Maybe their sheer density. Maybe genetics. Maybe behavior. Often nowadays, when I see the mark on the tree, I recall what Greg Dwyer told me: It all depends.
NOTES
I. Pale Horse
24. “Viruses have no locomotion”: Morse (1993), ix.
28. “He remained deeply unconscious”: O’Sullivan et al. (1997), 93.
29. “It seems,” McCormack’s group concluded, “that very close contact”: McCormack et al. (1999), 23.
35. “Economically, it is the most important”: Brown (2001), 239.
41. “If you look at the world from the point of view”: William H. McNeill, in Morse (1993), 33–34.
44. “Furthermore, 71.8% of these zoonotic”: Jones-Engel et al. (2008), 990.
II. Thirteen Gorillas
54. “The chimpanzee seems to have been the index case”: Georges et al. (1999), S70.
70. “Only limited ecological investigations”: Johnson et al. (1978), 272.
71. “No more dramatic or potentially explosive epidemic”: Johnson et al. (1978), 288.
72. “No evidence of Ebola virus infection”: Breman et al. (1999), S139.
77. “Contact with nature is intimate”: Heymann et al. (1980), 372–73.
84. “Viruses of each species have genomes that”: Towner et al. (2008), 1.
87. “bad human-like spirits that cause illness”: Hewlett and Hewlett
(2008), 6.
88. a final “love touch” of the deceased: Hewlett and Amola (2003), 1245.
90. “This illness is killing everyone”: Hewlett and Hewlett (2008), 75.
91. “Sorcery does not kill without reason”: Hewlett and Hewlett (2008), 75.
92. “jumped from bed to bed, killing patients left and right”: Preston (1994), 68.
92. “transforms virtually every part of the body”: Preston (1994), 72.
92. “suddenly deteriorates,” its internal organs deliquescing: Preston (1994), 75.
92. “essentially melts down with Marburg”: Preston (1994), 293.
92. comatose, motionless, and “bleeding out”: Preston (1994), 184.
93. “Droplets of blood stand out on the eyelids”: Preston (1994), 73.
99. “It is difficult to describe working with a horse infected with Ebola”: Yaderny Kontrol (Nuclear Control) Digest, No. 11, Center for Policy Studies in Russia, Summer 1999.