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["DUCLAYAN, GINA" <GDUCLAYAN AT popcouncil.org>]

December 5, 2000, New York Times
For Monkeys, a Millipede a Day Keeps Mosquitoes Away
By NATALIE ANGIER
Upcoming titles from that little- known publishing house, Capuchin Press:
"Don't Swat the Small Stuff," "Who Moved My Millipede?" and "Bananas from
Heaven: A True Story of Monkeys, Mosquitoes and Miracles."
Researchers studying a group of wedge-capped capuchin monkeys that live in
tropical forests of central Venezuela have discovered that the monkeys
protect themselves against the annual merciless onslaught of mosquitoes
exactly as humans do: by rubbing themselves with mosquito repellent.
But while humans may reach desperately for spritzers or bottles or laughably
overhyped "protective" skin-so-softeners, the capuchins have learned to poke
around in tree bark or termite mounds to extract a wriggling specimen of
Orthoporus dorsovittatus, a millipede rich with powerful defensive chemicals
called benzoquinones.
The triumphant monkey will then proceed to anoint itself head to foot with
the repellent secretions by massaging the four-inch-long millipede into its
fur.
And just as the benzoquinones discourage virtually all insects from
harassing the millipedes, so the transferred chemicals appear to protect
capuchins against the mosquitoes that otherwise would descend on them during
the rainy season in sopranic clouds of misery. 
The new work offers the most persuasive evidence yet that nonhuman primates
are industrious chemical prospectors, putting organic materials to good
medicinal use. Other researchers have suggested that primates use plant
products as antibiotics, analgesics, even hallucinogenics.
But because most of the plant materials that primates have been observed to
dabble with are chemically complex, composed of hundreds if not thousands of
compounds, it has been difficult for scientists to demonstrate that the
animals were seeking a specific ingredient from any given sample.
In the new study, the researchers were able to demonstrate that the
millipede secretion consists of only two chemicals, both in the benzoquinone
family and both known to be potent insect repellents. 
Moreover, they demonstrated that the use of millipedes for fur anointment
corresponds closely with the annual peak in mosquito populations. "We think
this is the clearest case yet" of an animal's using organic material for
medicinal purposes, said Ximena Valderrama of Columbia University. "We're
fortunate that the chemical analysis leaves very little room for doubt." 
Ms. Valderrama, a graduate student in anthropology, is the principal author
of the new report, which appears in the December issue of the journal
Chemical Ecology.
Her co-authors are Dr. John G. Robinson of the Wildlife Conservation
Society, located at the Bronx Zoo, and Dr. Thomas Eisner and Dr. Athula B.
Attygalle of Cornell, who performed the chemical analysis of the secretions.
Nicknamed the "chimpanzees" of the New World for their high intelligence,
capuchins are the famed organ-grinder monkeys, their fur a mottled grayish
brown, their faces expressive and distinctively marked. They live in forests
throughout Central and South America, congregating in hierarchically
structured groups of maybe 25 to 35 individuals.
Dr. Robinson first observed the odd millipede massage behavior when he began
studying a capuchin group at the Fundo Pecuario Masaguaral reserve in
Venezuela in 1977, but it was not until Ms. Valderrama devoted herself to
studying it full time that the precise nature of the ritual became clear.
As it happens, the monkeys have a real need of insect repellent.
Beyond the obvious annoyance factor, mosquitoes also serve as vectors of the
parasitic bot fly, delivering fly eggs beneath a monkey's skin that then
form debilitating, festering cysts in which maggots develop until they are

mature enough to burst free.
Given the bot fly risk, it seems, the capuchins are willing to take risks of
their own: the benzoquinones that they apply to their fur, Dr. Eisner said,
are many times stronger and more toxic than the most powerful "deep woods"
mosquito repellent the United States Army can supply. Nevertheless, a
capuchin will often pop a millipede into its mouth before anointment,
presumably to help release the secretions.
When Dr. Eisner tried the same feat, Ms. Valderrama said, "He immediately
fell to his knees, it was so painful and irritating." Yet, while a monkey
may drool and its eyes glaze over from the millipede mouthing, it sets to
work anointing itself forthwith. 
In addition to its medicinal value, millipede rubbing also serves as a
social lubricant. The monkeys engage in rubdowns practically en masse,
passing a single millipede from one to another.
"You'll see one or more monkeys looking frenzied and agitated, their bodies
contorted as they're patting themselves all over," said Ms. Valderrama.
And should a monkey insist on bogarting its millipede, the other monkey
simply rubs its body against the anointed one's fur to pick up some stray
secretions. 
Of interest to the researchers is the egalitarian nature of the millipede
ritual. Whereas the monkeys normally hew to strict hierarchies when it comes
to who gets the best food and who grooms whom, there are no obvious top or
rotten bananas in the sharing of millipede secretions.
The researchers have yet to demonstrate that the use of millipedes prevents
bot fly infestation among monkey participants. They also do not yet know if
the use of insect repellent is common among capuchins, or is limited to the
intensively studied group at the Venezuelan reserve.
There, at least, the custom is entrenched, and for all the demonstrated
carcinogenicity of benzoquinone, the capuchins do not appear to have
suffered long-term consequences from exposure to it, many of them living
more than 30 years.
As the infant monkeys learn early on, the family that sprays together, stays
together. 
Copyright 2000 The New York Times Company