- Author: Kathy Keatley Garvey
For the past three decades, wooly bear caterpillars have accurately predicted a Republican or Democrat win in the U.S. Presidential elections.
This year, despite the pollsters, pundits and political fervor, the woollies again successfully predicted the outcome.
Just as noted UC Davis ecologist Richard “Rick” Karban and his lab prognosticated.
Karban and his fifth-year doctoral student, Eric LoPresti, study the wooly bear caterpillars, which populate the cliffs of the Bodega Marine Reserve, above the Bodega Marine Laboratory, Sonoma County. The fuzzy reddish-black caterpillars, which feed primarily on lupine, are the immature form of the Ranchman's Tiger Moth, Platyprepia virginalis.
Sometimes the population booms; other times, it's a bust, said Karban, a professor in the UC Davis Department of Entomology and Nematology and a fellow of the American Association for the Advancement of Science. In their 30-year census of the same lupine patch, they noticed that when the population thrives, a Democrat heads to the White House. When the population dives, the Republicans take over.
And why not? “Paul the Octopus had a pretty good run predicting soccer matches in 2012, so perhaps the wooly bears have earned as much credibility at forecasting this presidential election,” Karban said last May.
Although most polls forecast a Democratic win, the UC Davis Wooly Bear Presidential Election Outlook did not.
However, they are not all that pleased with the outcome. “We're kind of bummed,” Karban said. “We didn't want to believe that the wooly bears were predicting a red outcome.”
The scientists, who study insect-plant interactions, first announced their presidential outcome predictions in a poster displayed at the 2014 Ecology Society of America meeting, held in Sacramento. Then this year, on April 25, they expanded on the concept, complete with intricate charts plotted in red and blue, in LoPresti's Natural Musings blog, “The wooly Bear Presidential Election Outlook 2016,” co-written by scientists in the Karban lab.
“Each March, Karban censuses the same patches of lupine that he has for over 30 years,” LoPresti explained in Natural Musings. “The study asks a vexing question: Why are there are so many caterpillars in some years and so few in others? Many insects, including pests cycle like this, therefore it is of keen interest to many. Dozens of papers later, Karban, his students, and his collaborators have answered a great many questions, including how caterpillars deal with parasites, whether population cycles are influenced by rain, whether caterpillars enjoy eating plant hairs, and how caterpillars avoid their predators.”
The wooly bears, as presidential forecasters, drew national attention. Washington Post reporter Karin Bruilliard ran with it in a piece published April 26: “These Fuzzy Little Caterpillars Are Better at Predicting Elections Than Most Pundits.”
“Who's going to win the presidential election?” Bruilliard asked. “Heck if we know. Try to answer that question without a crystal ball and you'll run head-on into a dizzying array of national polls and state polls, fundraising tables and delegate counts, endorsements and prediction markets.”
LoPresti posted in his Natural Musings blog on April 25 that the woollies “seem to be leaning Republican.”
“Given their (pollsters') wildly erroneous predictions thus far for both primaries, trusting their predictions for the general election seems ill-advised,” LoPresti wrote. “The wooly bears, on the other hand, have a 100% accurate prediction record over the past 30 years. In years of low abundance, a Republican is elected, and in years of high abundance, a Democrat.”
“A superficial examination suggests that 2016 will be a Republican year – wooly bear abundance is not particularly high,” LoPresti noted. “However, looking a little closer, it may not be. The number of wooly bears per lupine bush in 2016 (0.53) is higher than the average Republican year by 152% and is 36% above the highest Republican year ever recorded (1988). However, it is only 27% of an average Democratic year and still only 36% of the lowest Democratic year (2008). This result is without presidential precedent in the last 30 years.”
What about the next presidential election, now that Vice President Joe Biden has indicated he might run?
“The wooly bears have not weighed in on Joe Biden,” Karban said.
Karban, internationally known for his work on plant communication, is the author of the book, Plant Sensing and Communication (University of Chicago Press), hailed as a landmark in its field. He has researched plant communication in sagebrush (Artemisia tridentata) on the east side of the Sierra since 1995.
Plants can eavesdrop, sense danger in the environment, and can distinguish friend from foe, Karban says. A plant under a predatory attack will emit volatile chemical cues, enabling its neighboring plants to adjust their defenses to better protect themselves.
Karban is featured in the Dec. 23-30, 2013 edition of The New Yorker in Michael Pollan's piece, “The Intelligent Plant: Scientists Debate a New Way of Understanding Plants."




- Author: Kathy Keatley Garvey
Let's hear it from the insects, namely the woolly bear caterpillars that populate the cliffs of Bodega Bay.
They may know.
A UC Davis ecologist and his lab who study woolly bear caterpillars, the immature form of the Ranchman's Tiger Moth, Platyprepia virginalis, think that the "bears" will again predict the winner, as they have for the past three decades.
The woolly bears feed primarily on lupine along the cliffs of Bodega Bay, says professor Richard "Rick" Karban of the UC Davis Department of Entomology and Nematology. Sometimes the population booms; other times, it's a bust. When the population thrives, a Democrat heads to the White House. When the population dives, the Republicans take over.
The UC Davis scientists, known for their expertise in plant-insect interactions, are now making national headlines with their political predictions.
“The pollsters and talking heads seem unable to size up this election cycle,” said Karban. “Paul the Octopus had a pretty good run predicting soccer matches in 2012 so perhaps the woolly bears have earned as much credibility at forecasting this presidential election.”
“The woollies aren't seemingly as decided as they have been in years past - I don't know what they are really predicting,” said graduate student Eric LoPresti. “They seem to be leaning Republican but the point is between the range that we've seen in the past for each party.”
Washington Post reporter Karin Bruilliard picked it up and ran with it on April 26 in a piece titled, “These Fuzzy Little Caterpillars Are Better at Predicting Elections Than Most Pundits.”
This year, however, the pollster findings are unclear, they agreed. “Given their wildly erroneous predictions thus far for both primaries, trusting their predictions for the general election seems ill-advised,” LoPresti wrote. “The woolly bears, on the other hand, have a 100% accurate prediction record over the past 30 years. In years of low abundance, a Republican is elected, and in years of high abundance, a Democrat.”
“A superficial examination suggests that 2016 will be a Republican year – woolly bear abundance is not particularly high,” LoPresti noted. “However, looking a little closer, it may not be. The number of woolly bears per lupine bush in 2016 (0.53) is higher than the average Republican year by 152% and is 36% above the highest Republican year ever recorded (1988). However, it is only 27% of an average Democratic year and still only 36% of the lowest Democratic year (2008). This result is without presidential precedent in the last 30 years.”
So, which party, which political animal (elephant or the donkey), will occupy the White House come Jan. 1, 2017? What do the bears indicate?
“We suspect that the Republicans have the edge,” the UC Davis scientists surmised. “However, a valid hypothesis would be a third-party winner, such as a right-leaning independent (a logical placeholder in between Democrats and Republicans). Perhaps Donald Trump will take particular interest in our data. Alternately, a contested Republican convention could produce a fractured party and the old Republican woolly bear average would not accurately represent the mean caterpillar abundances seen by this new party.”
Responding to the April 25 blog, someone noticed the resemblance of the hair of a presidential candidate to the hair of the woolly bear caterpillar.
The UC Davis scientists study the caterpillars at the Bodega Marine Reserve above the Bodega Marine Laboratory. The reserve, which surrounds the Bodega Marine Laboratory, is a unit of the University of California Natural Reserve System and is administered by UC Davis.
“Platyprepia virginalis caterpillars are dietary generalists and feed on multiple host species within a single day,” Karban says.
In research, Diet Mixing Enhances the Performance of a Generalist Caterpillar, Platyprepia virginalis, published in February 2010 in the journal Ecological Entomology, “We found that relative growth rates and rates of survival were higher when they fed on mixed diets compared to lupine only,” Karban said. These results were consistent with hypotheses that mixed diets provided balanced nutrition, diluted toxins, and/or allowed recovery from parasitoids, although our data did not allow us to separate these non-exclusive explanations.”
The caterpillar's taste for plants containing alkaloids may help it survive parasitoids, Karban said.

- Author: Kathy Keatley Garvey
If you're planning to hike the hills around Bodega Head in Sonoma County, watch out for the bears.
The woolly bear caterpillars, that is.
Last Sunday, with the temperature hovering around 70 degrees, the woolly bears were everywhere. They were munching on the gray-green leaves of Lupinus arboreus (yellow bush lupine), not yet blooming. We also spotted them on yellow mustard and wild radish, both members of the Brassicaceae family and both abloom.
If you look closely at these little caterpillars, they seem to be having a bad hair day. They look as if they just encountered a jolt of static electricity.
They're also known as the larvae of Ranchman's Tiger Moth (Platyprepia virginalis). Once they become moths, they do not resemble woolly bears any more.
Rick Karban, professor of entomology at UC Davis, has published a number of research papers on these herbivores.
"Platyprepia virginalis caterpillars are dietary generalists and feed on multiple host species within a single day," he wrote recently in Ecological Entomology. "We conducted field experiments to evaluate their performance on diets consisting of only their primary food, Lupinus arboreus, or diets consisting of L. arboreus plus other acceptable host species."
"We found that relative growth rates and rates of survival were higher when they fed on mixed diets compared to lupine only."
That feeding behavior we saw, too. A lupine lunch, with a touch of mustard and radish.

