- Author: Kathy Keatley Garvey
Ever seen the wooly bear caterpillar, Arctia virginalis, formerly known as Platyprepia virginalis?
It's found in low elevations in western North America, from southern Monterey Bay, across Nevada and southern Utah to Colorado, and north to southern British Columbia.
We see it on spring and summer hikes on the trails of Bodega Head, Sonoma County, where it's often foraging on fiddleneck.
In its adult stages, it is commonly known as Ranchman's tiger moth, a diurnal or day-flying moth. French lepidopterist, botanist and physician, Jean Baptiste Alphonse Déchauffour de Boisduval (1799-1879) first described it in 1852.
This is the caterpillar that UC Davis distinguished professor Richard "Rick" Karban, a community ecologist, has studied for four decades. His research site is at the Bodega Marine Reserve, where he studies "the factors that control the abundance and spatial distribution of wooly bear caterpillars." Karban, who plans to retire this June, has published numerous papers on the wooly bear caterpillar. (Fred's Ecology and Environmental Tales commented on one paper dealing with climate change: "Karban and his students explored three hypotheses for why caterpillars increased following a year with numerous heavy rainfall events. First, perhaps more rain causes more plant growth and deeper litter, providing extra food for caterpillars. Second, heavy rains may reduce the number of predacious ground-nesting ants. Lastly, heavy rains may produce deeper denser litter providing refuge from predacious ants."
The Washington Post featured Karban's research in an article titled "These Fuzzy Little Caterpillars Are Better at Predicting Elections Than Most Pundits," published April 26, 2016.
Want to learn more about moths? Attend the Bohart Museum of Entomology open house on moths on Saturday night, July 20. Moth Night is from 7 to 11, with activities scheduled both inside and outside the museum. It's free and family friendly, Parking is also free on the weekends.
The Bohart Museum, part of the UC Davis Department of Entomology and Nematology, is located in Room 1124 of the Academic Surge Building, 455 Crocker Lane, UC Davis campus.
Director of the Bohart is Professor Jason Bond, the Evert and Marion Schlinger Endowed Chair, UC Davis Department of Entomology and Nematology, and associate dean, UC Davis College of Agricultural and Environmental Sciences. He is president-elect of the American Arachnological Society.
- Author: Kathy Keatley Garvey
You gotta love those wooly bear caterpillars.
Richard "Rick" Karban, UC Davis distinguished professor of entomology, studies them. The rest of us admire them.
We usually see them in the spring along the cliffs of Bodega Head on the Sonoma coast. They're reddish brown in the center and black on both ends.
Some folks say they're winter weather predictors. Not! We do, however, see them curl into a bristly ball when they sense danger.
The National Weather Service (NWS) says: "According to folklore, the amount of black on the wooly bear in autumn varies proportionately with the severity of the coming winter in the locality where the caterpillar is found. The longer the wooly bear's black bands, the longer, colder, snowier, and more severe the winter will be. Similarly, the wider the middle brown band is associated with a milder upcoming winter. The position of the longest dark bands supposedly indicates which part of winter will be coldest or hardest. If the head end of the caterpillar is dark, the beginning of winter will be severe. If the tail end is dark, the end of winter will be cold. In addition, the wooly bear caterpillar has 13 segments to its body, which traditional forecasters say correspond to the 13 weeks of winter."
"As with most folklore, there are 2 other versions to this story," NWS acknowledges. "The first one says that the wooly bear caterpillar's coat will indicate the upcoming winter's severity. So, if its coat is very wooly, it will be a cold winter. The final version deals with the woolly bear caterpillar's direction of travel of the worms. It is said that wooly bear's crawling in a southerly direction are trying to escape the cold winter conditions of the north. On the other hand, wooly bear's crawling on a northward path would indicate a mild winter."
If you attend the Bohart Museum of Entomology Moth Night at UC Davis, you'll see specimens of the adults--the tiger moths, Arctia virginalis. They're sometimes called the "Ranchman's Tiger Moth." They are boldly marked, like a tiger. (Who says moths are drab-looking?)
The Bohart is celebrating National Moth Night from 8 p.m. to 11 p.m. on Saturday, July 30: both (1) indoors in Room 1124 of the Academic Surge Building, 455 Crocker Lane, UC Davis campus, and (2) outdoors, by the blacklighting display, within a short walking distance.
Indoors you'll see the Bohart's global collection of moths, and outside, you'll see moths and other insects hanging on a white sheet in the blacklighting display. They are drawn there by an ultraviolet (UV) light.
The open house is free, family friendly and open to the public. A craft activity is planned and refreshments (hot cocoa and cookies) will be served, says Tabatha Yang, education and outreach coordinator.
The Bohart Museum, founded in 1946 and directed by Lynn Kimsey, UC Davis distinguished professor of entomology, houses a worldwide collection of eight million insects. It also houses a live "petting zoo" (Madagascar hissing cockroaches, stick insects and tarantulas) and an insect-themed gift shop.
- Author: Kathy Keatley Garvey
Eastern Finland University in Kuopio will be his host institution, where he will work with James Blande of the Chemical Ecology Group, Department of Environmental Sciences. Grof-Tisza met Blande while he was collaborating with Karban--his major professor and now his postdoctoral advisor--on a project involving plant-plant communication and induced resistance within sagebrush.
“The focus of my Curie postdoc will be to continue this research and to investigate community-wide effects of volatile-mediated communication,” Grof-Tisza said. “I will conduct field research in the Eastern Sierra in the spring and summer and will spend the rest of the year in Finland conducting laboratory experiments and analyzing samples collected over the field season.”
Grof-Tisza's dissertation work involved investigating how bottom-up and top-down forces regulated a focal herbivore, the Ranchman's tiger moth (Arctia virginalis; the wooly bear caterpillar that Karban has been studying since 1983) within the Bodega Marine Reserve.
“Through this work, I became interested in plant defenses, both mechanical and chemical – the primary host plant of A. virginalis contains alkaloids, which are known to deter herbivores.” He also has collaborated on several projects with his lab mate, Eric LoPresti, who studies the efficacy of sand-entrapment as a defense in sticky plants.
“I applied to the Marie Currie Fellowship to continue studying plant defenses as well as learn laboratory techniques, including those pertaining to gene expression and mass spectrometry,” said Grof-Tisza who received his bachelor's degree in molecular biology, summa cum laude, at Frostburg (Md.) State University, and then worked as a biochemist in the biotech industry prior to enrolling in graduate school at UC Davis. As a member of the Ecology Graduate Group, he received his doctorate in 2015 from UC Davis, working with advisors Richard Karban and Marcel Holyoak, a professor in the Department of Environmental Science and Policy.
“This second postdoc,” Grof-Tisza said, “will allow me to combine the ecological knowledge I have gained as a graduate student with the laboratory skills I learned earlier in my career.”
In his fellowship proposal abstract, Grof-Tisza noted “Plants have evolved an impressive defense system to combat herbivores. These defenses include morphological structures like spines and secondary metabolites that have toxic, repellent, or antinutritional effects on consumers. Many plant defenses are constitutively expressed, but some are induced in response to herbivore damage. Damaged plants emit volatile organic compounds (VOCs) into the environment that may induce defenses in adjacent, undamaged tissue or may be eavesdropped by neighboring plants, enabling them to prime their own resistance response prior to attack.”
“While once controversial, this plant-plant communication resulting in a VOC-induced phenotypic response that reduces damage from attacking herbivores has been demonstrated in over 50 species,” he wrote. “Recently, researchers have found distinguishing VOC blends among sagebrush (Artemisia tridentata) referred to as chemotypes. Field experiments demonstrated that communication between A. tridentata plants of the same chemotype resulted in less damage by herbivores compared to that between plants of different chemotypes. Chemotypes were also found to be highly heritable.”
Grof-Tisza wrote that “this is consistent with the hypothesis that volatile communication evolved as a within-plant warning mechanism due to limited vascular signaling. Because emitted volatile cues become available to potential competitors of the same or different species, selection for cues that are more private would likely be of greater benefit to the emitter. At the time of this study, only two A. tridentata chemotypes had been identified. More recent work has found an additional six chemotypes.
“Here we propose to rigorously test the ecological consequences of chemotypic variation and the processes that maintain it. Through synergistic efforts combining my expertise in field ecology and plant-insect interactions and that of the host and collaborators in ecological chemistry and molecular biology, we will forward the field of volatile-mediated plant-plant interactions.”
Grof-Tisza has published his work in a number of journals, including Ecology, Evolution and Ecology, Journal of Animal Ecology, Journal of Chemical Ecology, Ecological Entomology, Bulletin of the Ecological Society of America, Biological Conservation and Oikos. He served as an adjunct professor with the Department of Science and Engineering, American River College, Sacramento, from 2015 to 2016.
Born in Queens, N.Y., but raised in Somerset, Pa., Grof-Tisza has resided in Davis since 2007.
- Author: Kathy Keatley Garvey
If you enjoy climbing the cliffs of Bodega Head on the Sonoma coast, keep your eyes out for bears--wooly bear caterpillars, that is.
The so-called "wooly bear caterpillar" is reddish, black and woolly and has a voracious appetite much like that of Joey Chestnut. It is the Ranchman's Tiger Moth caterpillar, Platyprepia virginalis, now changed to Arctia virginalis.
Richard "Rick" Karban, professor of entomology at the University of California, Davis, studies this critter. "It has a taste for most alkaloid containing plants, like fiddleneck, although it doesn't appear to sequester the alkaloids," he told us. "The alkaloids may help caterpillars survive their parasitoids, however."
We saw about five of the wooly bear caterpillars on a public trail near the Bodega Marine Reserve above the Bodega Marine Laboratory on April 17.
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.
Several wooly bear caterpillars were munching on fiddleneck. Another rolled around near a patch of California poppies and we couldn't tell what its menu included. It looked good, though!
You can read Karban's research on "Diet Mixing Enhances the Performance of a Generalist Caterpillar, Platyprepia virginalis," published last February in the Ecological Entomology journal.