BOOK REVIEW
Entomological Tales
William Shear
For Love of Insects. Thomas Eisner. xiv + 448 pp. The
Belknap Press of Harvard University Press, 2003. $29.95.
In his introduction to Thomas Eisner's For Love of Insects,
Edward O. Wilson calls Eisner "the modern Fabre"—an
apt comparison, but one that may not mean much to modern readers, at
least those outside entomology. Jean-Henri Fabre (1823–1915)
was perhaps history's most acute observer of insect life, although
he worked largely unrecognized until he was in his eighties. In
1907, the last of the 10 volumes of his Souvenirs
Entomologiques appeared, and three years later, Fabre was
lauded throughout France as a naturalist and as a literary stylist.
For the last five years of his life, he enjoyed international fame,
and dignitaries journeyed to his harmas (an untilled,
pebbly expanse of land) in the small village of Sérignan to
meet him.
Eisner brings the originality and practicality of Fabre to his own
study of insects, but whereas Fabre epitomized the 19th-century
tradition of the amateur naturalist, Eisner is a modern-day
professional scientist. His work, unlike that of Fabre, is
illuminated by a combination of evolutionary theory and
technological innovation. Fabre's accounts of the lives of the
insects he studied remain fascinating, if compartmentalized,
stories. Eisner's work, summarized for the first time in this
elegantly written and beautifully illustrated book, presents a
coherent picture of a world little known even to many biologists.
During his graduate work at Harvard, Eisner formed a determination
to combine his passion for insects and his interest in chemistry to
"decipher the chemical language of insects." In 1955 he
first encountered the bombardier beetles that were to catalyze a
career-long theme: how insects use chemistry to cope with the
challenges of their environment. In the course of many episodes of
careful observation in nature and elaborate experimentation in the
laboratory, Eisner and his major collaborators—his wife,
Maria, and chemist Jerrold Meinwald—would found and develop
the field of chemical ecology.
In this day of the nature documentary, Eisner does not share the
obscurity Fabre so long endured. Eisner's work has been the subject
of several television programs, in which the devoted entomologist is
also seen as a genial and articulate spokesman for the scientific
view of life. His sparkling lectures, complete with live
demonstrations of the chemical armamentarium of arthropods, have
delighted hundreds of students. And in this book, the reader almost
gets the experience of a conversation with Eisner, as he leads us
through a familiar, yet alien, country.
Eisner's way of working was established on that day in 1955 when he
"felt the heat" of the bombardier beetle's discharge of
its defensive chemicals. It is a process that begins with a
walkabout in the woods, often the Florida scrub of his favorite
field site, the Archbold Biological Station. Something odd, or
something commonplace looked at in a new way, triggers a question.
An experiment might be devised on the spot, and if the prospect pans
out, the insect of interest is taken in numbers to the laboratory at
Cornell, where the hammer and tongs of everything from high-speed
cinematography to scanning electron microscopy and gas
chromatography are applied. What results is usually a cascade of new
questions that pull Eisner and his collaborators further and further
into the world of an insect.
The book becomes a manual for discovery. In the chapter on the
bombardier beetle, Eisner details how he worked out the chemistry of
its weapon. Microthermocouples revealed that the spray leaves the
beetle's rear end at a temperature of 100 degrees Celsius. Discovery
by the team that the discharge is pulsed at 500 to 1,000 blasts per
second led to a collaboration with Harold "Doc" Edgerton
and the production of an almost incredible high-speed film showing
the beetle's chemical machine gun in action.
In the chapters that follow, Eisner introduces spiders that signal
birds of their webs' presence, termites that harbor a chemical
cannon in their heads and firefly females that lure—and then
kill and eat—males of another genus of firefly by imitating
the sexual signals of females of that genus. A fearsome-looking
creature called a vinegaroon, or whipscorpion, spritzes predators
with a blistering mixture of acetic and caprylic acids. Insect
larvae disguise themselves with everything from their own feces to
hairs gleaned from their host plants. A tiny millipede is its own
tar baby, studded with hooked hairs that hopelessly entangle
attacking ants. If defense and deception seem themes of these tales,
it is because insects live in a terrifyingly dangerous world and use
the tools at their command to survive and reproduce. The insight
that many of these are chemicals is the "one big thing" in
Eisner's research.
In the penultimate chapter, all the many threads of the book are
drawn together in an extended account of Eisner's 30 years spent
studying the moth Utetheisa ornatrix. This beautiful moth
obtains a pyrrolizidine alkaloid from its host plant (any of various
species of Crotalaria) and uses it as a defense against
predators. The alkaloid also appears in the moth's eggs, contributed
not only by the mother but also by the father, with the sperm
package. Females lure males with a simple hydrocarbon pheromone and
then assess their nuptial gift of alkaloid by their production of
hydroxydanaidal, which may be derived from pyrrolizidine alkaloid.
Eisner describes the elegant, simple experiments used to unravel the
chemical web that links these moths to one another, to their host
plant and to their predators. Nearly every insect he has
investigated has a similar story to tell, and there must be
thousands more.
The telling of entomological tales joins Eisner to Fabre once again.
But Fabre, despite an extensive correspondence with Charles Darwin,
never accepted natural selection and never linked his many
observations into a theoretical framework. Eisner is a convinced
Darwinian, and each of his chapters is another brick in an edifice
supporting natural selection, joining the already numerous examples
of that process in action, examples that make it possible for
biologists to internalize the theory. Young naturalists who read
this book will not only understand the scientific process, they will
also absorb an intuitive understanding of evolution and how it works.
In this book-long conversation with Eisner, a few glimpses of the
life paralleling the work slip out. He speaks briefly of his
family's flight from Germany in the 1930s, his boyhood in Uruguay,
his half-century of friendship with Ed Wilson and his love of music.
Scattered among Fabre's Souvenirs are autobiographical
essays that tell us much of the old Frenchman's character. I hope
that before too much time passes, Eisner will write more about
himself—his own story is likely as fascinating as any of those
he tells in this book.—William A. Shear, Biology,
Hampden-Sydney College, Virginia