- Author: Kathy Keatley Garvey
Yigen Chen and Steve Seybold continually trapped the reddish-brown insect, about a third of the size of a grain of rice, for three years along Putah Creek in Davis, Calif., and recorded its daily and seasonal flight behavior. They lured the insect into the traps with a synthetic version of its aggregation pheromone.
“We discovered the collective and interactive effects of four environmental factors on the crepuscular (twilight) flight behavior of the insect,” said lead author Chen, a research entomologist and project scientist with the UC Davis Department of Entomology and Nematology. “We found that the optimal trapping conditions are a combination of moderate to warm temperatures, around 79 to 81 Fahrenheit; low light intensity; low wind speed, 0.6 to 2.5 miles per hour; and moderate barometric pressure, 755 to 757.”
“Understanding the walnut twig beetle's seasonal flight cycle and factors that govern its flight are critical first steps in the early detection of invasive species prior to implementing pest eradication or integrated pest management (IPM) programs,” they wrote in their research article, “Crepuscular Flight Activity of an Invasive Insect Governed by Interacting Abiotic Factors,”published in the Aug. 26 edition of the Public Library of Science, PLOS ONE.
However, when coupled with a hitchhiking fungus, Geosmithia morbida, it causes what is known as thousand cankers disease. The beetles create numerous galleries beneath the bark, resulting in fungal infection and canker formation. The large numbers of cankers led to the name, thousand cankers disease.
As the disease advances, the health of the tree declines and eventually it dies, sometimes within a three-year period, said Seybold, who has been studying the beetle and the newly discovered fungus with its barrel-shaped spores since 2008.
When male beetles initiate new galleries, they produce an aggregation pheromone. As the population increases, the flight response of males and females similarly increases.
Mating disruption or interruption of insect aggregation is crucial to controlling such insect pests as the walnut twig beetle in IPM programs, the entomologists pointed out. “Understanding the interactions among abiotic environmental factors on flight activity, should increase the efficacy of these methods in a specific IPM program to control the beetle,” Chen said.
“The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed,” they wrote in their abstract. “A model selection procedure indicated that the four abiotic factors collectively and interactively governed P. juglandis diurnal flight.”
New knowledge of the primary periods of seasonal flight (May‒July and September‒October) “provides some guidance for when semiochemical-based interruption of aggregation may be applied most efficaciously,” they said..
Seybold, one of the first scientists to study the beetle and fungus in California, served on a scientific team that developed guidelines and trapping methods for the beetle. In 2010 and 2011, the team discovered and later patented the aggregation pheromone for the beetle and conducted scientific trials in northern California.
Late in the summer of 2011, the team demonstrated the efficacy of the pheromone as a flight trap bait. The bait lures both male and female beetles into a small plastic funnel trap.
The walnut twig beetle, native to the southwestern United States and Mexico, and widely distributed in Colorado, Arizona, California, and New Mexico, has now been detected throughout much of the United States: in nine western and five eastern states. In 2013, it was reported in northern Italy.
The earliest symptom of thousand cankers disease is yellowing foliage that progresses rapidly to brown wilted foliage, then finally branch mortality. Branch mortality and decline of the tree crown are one of three major symptoms of thousand cankers disease. The others are numerous small cankers on branches and the trunk, and holes and other evidence of tiny bark beetles.
Related links:
- Thousand Cankers Disease and the Walnut Twig Beetle in California (UC IPM)
- Walnut Twig Beetle (USDA Forest Service)
- Pest Alert, Walnut Twig Beetle and Thousand Cankers Disease (Colorado State University)
- Thousandcankers.com (This site is a collaborative effort between the Northeastern Area State and Private Forestry, the USDA Forest Service Northern Research Station, the Purdue University Department of Forestry and Natural Resources, the Hardwood Tree Improvement and Regeneration Center, the American Walnut Manufacturers Association, and the Walnut Council.)
- Author: Kathy Keatley Garvey
The distinction recognizes outstanding professors who have achieved the highest level of scholarship, in that they are globally recognized for their research and also known for their excellence in teaching. The UC Davis Department of Entomology and Nematology has four other distinguished professors: nematologist Howard Ferris and entomologists Bruce Hammock, Frank Zalom and Thomas Scott.
Carey, whose work spans four decades, is considered the world's foremost authority on insect demography; a worldwide authority on the demography and invasion biology of tephritid fruit flies, particularly the Mediterranean fruit fly; and a preeminent authority on biodemographics of human aging and lifespan. He is also a pioneering force advocating the educational use of digital video technology, work that he is sharing throughout much of the state, nation and the world.
For 10 years, Carey served as the principal investigator and director of the multidisciplinary, 11-institution, 20-scientist program “Biodemographic Determinants of Lifespan,” which received more than $10 million in funding from the NIH/NIA from 2003 to 2013.
Carey has published more than 200 scientific papers and three books on arthropod demography, including the monograph Longevity (Princeton, 2003) and the “go-to” book on insect demography, Demography for Biologists with Special Emphasis on Insects (Oxford, 1993). His landmark paper on “slowing of mortality at older ages,” published in Science in 1992 and cited more than 350 times, keys in on his seminal discovery that mortality slows at advanced ages. The UC Davis College of Agriculture and Environmental Science cited this as one of “100 Ways in Which Our College Has Shaped the World.”
In his quest for developing concepts for estimating the age structure of insect populations, Carey discovered a new analytical property of life tables--known in demographic circles as Carey's Equality--that the death distribution in a life table population equals its age structure. It is a unique property of the life table that connects it to a stationary population. Scientists consider the discovery remarkable for two reasons: first, that it was unknown despite the 150-year history of the life table, and second, that it was discovered by an entomologist and not by any of the thousands of mathematicians, demographers or actuaries that study and apply them.
His groundbreaking paper documenting medfly establishment in California (Science 1991) generated what scientists described as much-needed discussion within the entomological community about definitions of eradication, the concept of subdetectable levels of invasive pests, and the need for a paradigm shift in invasion biology of economically and medically important arthropod pests.
Carey also is known for his involvement with the light brown apple moth eradication in northern California, testifying to the California Legislature, California Assembly Agriculture Committee, California Senate Environmental Quality Committee, San Francisco Board of Supervisors, California Roundtable for Agriculture and the Environment, Senator Migden hearings, Nancy Pelosi staff meetings, and California Senate Committee on Food and Agriculture. For his work involving the light brown apple moth, Carey was named “Hero of the San Francisco Bay” in 2008 by the San Francisco Bay Guardian along with botanist Daniel Harder, executive director of the UC Santa Cruz Arboretum, and horticulturist Jeff Rosendale, who operates a nursery in Soquel.
Carey chaired the systemwide UC Committee on Research Policy and served on the system-wide UC Academic Council. He currently chairs the 2014-15 Education Technology subcommittee of UC Davis Campus Council for Information Technology (CCFIT), which provides advice and recommendations to key UC Davis administration on educational and information technology and its use at UC Davis in support of instruction, research, administration and public service/
Another highlight of his digital technology work is his key role as an advisor of the nine-university CARTA (Consortium for Advanced Research Training in Africa). He recently delivered presentations in two African counties on the use of the digital technology in research, teaching and outreach. He was the only invitee from the United States to participate in the workshops, one held in Nairobi, Kenya in March 2014 and the other in Kampala, Uganda in July 2014.
An innovative teacher and scientist, Carey this year received a UC Davis Academic Senate Distinguished Teaching Award and the C. W. Woodworth Award, the highest honor given by the Pacific Branch of the Entomological Society of America (ESA), for outstanding accomplishments in entomology.
In his teaching and/or digital technology projects, Carey
- Encourages students to learn through creative, innovative ways, such as the student-produced, instructor-directed video productions, “One Minute Entomologist” and “How to Make an Insect Collection (the latter won an award from the Entomological Society of America)
- Offers an innovative, online course, “Terrorism and War,” through the Science and Society program. It was selected one of 27 courses, UC systemwide, to receive grand support ($75,000) from UC Online.
- Served as the pioneering and driving force behind the UCTV Research Seminars; he began video-recording seminars in his department several years ago and then encouraged video-recording on all the other nine UC campuses.
- Partnered with Assistant Professor Sarah Perrault in the University Writing Program to produce a playlist of 13 videos, Write Like a Professor; The Research Term Paper.
- Designed and taught “Longevity,” a 4-credit course based on his research program in the biology and demography of aging (biodemography). He also created a kinship video.
In addition, Carey has presented more than 250 seminars in venues all over the world, from Stanford, Harvard, Moscow, Beijing to Athens, London, Adelaide and Okinawa. He serves as associate editor of three journals Experimental Gerontology, Demographic Research and Genus.
A former vice chair of the UC Davis Department, the distinguished professor is a senior scholar at the Center for the Economics and Demography of Aging at UC Berkeley, and a fellow of four professional societies across several disciplines: the Entomological Society of America, the American Association for the Advancement of Science, the Gerontological Society of America, and the California Academy of Sciences.
Carey received his bachelor's degree in animal ecology from Iowa State University; his master's degree in entomology from Iowa State University; and his doctorate in entomology from UC Berkeley. He joined the UC Davis Department of Entomology faculty in 1980.
- Author: Kathy Keatley Garvey
UC Davis Entomology and Nematology Photo Gallery for August 2014.
- Author: Kathy Keatley Garvey
Raymond Ryckman, emeritus professor of biochemistry and microbiology at Loma Linda University, San Bernardino County, gifted his collection, spanning more than half a century, to the Bohart Museum's growing global collection of nearly eight million specimens.
His donation includes 18 species of kissing bugs as well as 11 species of tsetse fly and other parasitic insects, said Lynn Kimsey, director of the Bohart Museum and professor of entomology at UC Davis.
“His collection is a tremendous addition to the Bohart Museum and we are honored that he thought of us to take care of it,” she said.
Kissing bugs, which feed on blood and transmit Chagas disease, are so named “because they often bite the thin skin around the lips and eyes of sleeping persons,” Kimsey said. In California, they're commonly found in the nests of wood rats and pack rats and in brush and woodpiles near homes. The insects are nocturnal. They invade residences, hiding in cracks and crevices by day and feeding on sleeping people at night.
Chagas disease, also known as American trypanosomiasis, is an inflammatory, infectious disease caused by the parasite, Trypanosoma cruzi, found in the feces of the kissing bugs, or triatomine (reduviid) bugs. According to the Centers for Disease Control and Prevention, the disease is found only in the Americas (mainly, in rural areas of Latin America where poverty is widespread).
Ryckman reared some of the parasitic insects from rotting cacti in Arizona and Mexico that comprised part of his thesis research. He authored more than 100 research papers and books, including a database on Chagas disease and its kissing bug vectors, assembling more than 23,000 references on the subject, Kimsey noted.
Ryckman also did research for Operation Whitecoat, operated by the U.S. Army Medical Research and Materiel Command at Fort Detrick, Maryland. He developed protocols for protecting troops and civilians from the disease. In 2007, he received a special Distinguished Achievement Award in 2007 from the Society of Vector Ecology. He has been a member of the Entomological Society of America since 1951.
Kimsey said kissing bugs are one of the most notorious insects belonging to the family Reduviidae. They feed exclusively on the blood of birds and mammals and “typically live in their hosts' nests,” she said.
Most of the species occur only in the Americas; and 12 are found in the United States. The most common species in California is Triatoma protracta, a large black or dark brown insect that occurs in the state's mountain ranges and in desert washes, where they live in rodent nests, Kimsey said. The insect is also known as the Western conenose, vinchuca, and Mexican bedbug.
“We tend to think of insect parasites like bedbugs and lice as being pretty small. However, kissing bugs are large, with the adults averaging about half-an-inch in length. They have a long narrow head and the mouthparts are modified into a long, apically pointed tube. At rest, this tube is folded up under the body.”
“The kissing bug's pharynx can generate suction pressures of 3-6 atmospheres. This makes the blood rush into the pharynx at the rate of 4 millimeters per second. You have to wonder what keeps the bug from exploding. However, they don't explode because a series of valves in their digestive track regulates the flow of blood. Some species excrete excess blood and digested materials during feeding.” They can create acute allergic reactions in humans. “Extreme allergic reactions occur more frequently from kissing bug bites than the bites of any other North American insects.”
Kimsey also pointed out that removing all brush and piles of debris away from homes in California is crucial for both fire protection and the elimination of rat nests.
“Pack rat nests are home to a diversity of insects and spiders besides kissing bugs,” she added. While doing research in the Algodones Dunes in Imperial County, “we found in a single pack rat's nest in a wash on the east side of dunes, Triatoma kissing bugs, black widow spiders, fleas, desert recluse spider and a diversity of beetles. I would not want to be a pack rat!”
Her comments appear in the summer 2014 edition of the Bohart newsletter.
- Author: Kathy Keatley Garvey
“Parasitoid Palooza” may be the first public celebration dedicated to parasitoids, said Lynn Kimsey, director of the Bohart Museum and professor of entomology at UC Davis, and Tabatha Yang, education and outreach coordinator. “Parasitoids are animals that feed internally or externally on a host to complete their development to an adult, ultimately killing it,” Kimsey said. “These insects are important biological control agents. We use them as biological control agents because they kill the host, sometimes as an egg or a larva.”
Most of the open houses are from 1 to 4 p.m., except for an evening event, “Moth Night” on Saturday, July 18, and two events--Biodiversity Museum Day on Sunday, Feb. 8 and UC Davis Picnic Day on Saturday, April 18--which have extended hours.
The Bohart Museum, located in Room 1124 of the Academic Surge Building on Crocker Lane, off LaRue Road, houses a global collection of nearly eight million specimens. The museum is open to the public four days a week, Monday through Thursday, but it sponsors special weekend open houses as well.
The schedule:
- Saturday, Sept. 27: “How to Be an Entomologist,” 1 to 4 p.m.
- Sunday, Nov. 23: “Insect Myths,” 1 to 4 p.m.
- Saturday, Dec. 20: “Insects and Art,” 1 to 4 p.m.
- Sunday, Jan. 11: “Parasitoid Palooza,” 1 to 4 p.m.
- Sunday, Feb. 8: “Biodiversity Museum Day,” noon to 4 p.m.
- Saturday, March 14: “Pollination Nation,” 1 to 4 p.m.
- Saturday, April 18: UC Davis Picnic Day, 10 a.m. to 3 p.m.
- Sunday, May 17: “Name That Bug! How About Bob?” 1 to 4 p.m.
- Saturday, July 18: “Moth Night,” 8 to 11 p.m.
The Bohart Museum is the home of the seventh largest insect collection in North America, and the California Insect Survey, a storehouse of the insect biodiversity. Noted entomologist Richard M. Bohart (1913-2007) founded the museum. The Bohart Museum's regular hours are from 9 a.m. to noon and 1 to 5 p.m. Mondays through Thursdays. The insect museum is closed to the public on Fridays and on major holidays. Admission is free.
Special attractions include a “live” petting zoo, featuring Madagascar hissing cockroaches, walking sticks and tarantulas. Visitors are invited to hold the insects and photograph them.
The museum's gift shop (on location and online) includes T-shirts, sweatshirts, books, jewelry, insect-collecting equipment and insect-themed candy.
Those interested in joining the Bohart Museum Society to support the educational mission can do so by signing up here. Benefits include:
- a subscription to the Bohart Museum Society quarterly newsletter
- invitation only special events and programs
- select member discounts on gift shop merchandise
- members-only Halloween open house
- access to the collections, and free information and identification services from staff
- use of the museum library of entomological books and periodicals
Through funds from the Bohart Society, the museum supports a visiting scientist program, high school student internships and associates program.
For those interested in naming an insect after themselves or for a loved one, the museum offers a BioLegacy program established to support species discovery and naming, research and teaching activities of the museum through sponsorships.
More information is available from Tabatha Yang at tabyang@ucdavis.edu or by telephoning (530) 752-0492. The website is at http://bohart.ucdavis.edu/