- Author: Kathy Keatley Garvey
It's good to see that the Xerces Society for Invertebrate Conservation and noted bumble bee expert Robbin Thorp of UC Davis have filed a petition with the U.S. Fish and Wildlife Service for Endangered Species Act protection for the beleagured rusty-patched bumble bee.
They previously filed a petition to save Franklin's bumble bee, a bumble bee known to inhabit a small area of southern Oregon and northern California. Thorp has been monitoring Franklin's bumble bee (Bombus franklini) since 1998 but hasn't seen it since August 2006 when he detected one at Mt. Ashland.
In a recent press release, the Xerces Society related that the rusty-patched bumble bee, (Bombus affinis), "has disappeared from 87 percent of its historic range (which once included 25 states). Where it is still found, this bee is much less abundant than it was in the past."
“The charismatic and once common rusty patched bumble bee has suffered severe and widespread declines throughout its range in the eastern U.S. since 1997," Thorp said. "The few scattered recent sightings thanks to intensive searches are encouraging, but the species is in critical need of federal protection.”
Why has the population of the rusty-patched bumble bee declined? Good question, and one with no fully determined answer, according to Thorp and Sarina Jepsen, the Xerces Society's endangered species program director.
"However, in related bumble bees that also are declining, researchers at the University of Illinois have recently found higher levels of a fungal pathogen and lower levels of genetic diversity," Jepson wrote in a press release. "Notably, the rusty-patched bumble bee was too scarce in the landscape to be included in these analyses."
"The leading hypothesis," Jepson says, "suggests that this fungal pathogen was introduced from Europe by the commercial bumble bee industry in the early 1990s, and then spread to wild pollinators. Although it has not been proven, the hypothesis is supported by the timing, speed and severity of the decline—a crash in laboratory populations of bumble bees occurred shortly before researchers noticed a number of species of formerly common bumble bees disappearing from the wild."
Meanwhile, we hope that Bombus affinis doesn't go the way of Bombus franklini.
As the Xerces Society's press release points out: "Pollinators are critical components of our environment and essential to our food security—providing the indispensable service of pollination to more than 85 percent of flowering plants and contributing to one in three bites of the food that we eat. Bumble bees are among the most widely recognized and well understood group of native pollinators in North America and contribute to the pollination of food crops such as squash, melon, blueberry, cranberry, clover, greenhouse tomato and greenhouse pepper, as well as numerous wildflowers."
Read more about this bumble bee from the Xerces website. And why researchers call the declining bumble bee population "alarming."
The Xerces Society, an international organization founded in 1971 and headquartered in Portland, Ore., is a nonprofit organization that "protects wildlife through the conservation of invertebrates and their habitat" and "is at the forefront of invertebrate protection worldwide, harnessing the knowledge of scientists and the enthusiasm of citizens to implement conservation programs."
- Author: Kathy Keatley Garvey
"Where'd that yellow pollen come from?"
Beekeepers who watch their bees return to their hives with pollen loads like to guess the origin of the pollen. Red, yellow, blue, white...
It's not unlike "What Color Is Your Parachute?" the job-hunting guide by Richard N. Bolles.
Sunday the bees foraging in flowering quince collected yellow pollen--heavy loads of pollen. They struggled with the weight and then headed home to help feed their colonies.
Blue skies, pink flowers, yellow pollen...life is good.
- Author: Kathy Keatley Garvey
UC Berkeley professor Nick Mills will head to UC Davis on Wednesday, Feb. 20 to speak on just that: "The Light Brown Apple Moth--Not a Typical Invader."
The seminar, hosted by the UC Davis Department of Entomology, is set from 12:10 to 1 p.m. in Room 1022 of the Life Sciences Addition, corner of Hutchison and Kleiber Hall drives.
Mills, with the UC Berkeley Department of Environmental Science, Policy and Management, says "exotic insect pests typically become invasive by building populations and spreading through a new geographic region in the absence of constraints from co-evolved natural enemies. While it is well known that environments can differ substantially in their resistance to invasions of alien species little is known of the factors responsible for this variation."
The light brown apple moth, aka LBAM, has caused quite a stir since its detection in California in 2006. That's when emeritus professor Jerry Powell of UC Berkeley discovered the invader in his back yard in Berkeley.
As a leafrolling caterpillar, LBAM loves just about everything from A to Z: apple, apricot, beans, caneberries (blackberry, blueberry, boysenberry, raspberry), cabbage, camellia, chrysanthemum, citrus, clover, cole crops, eucalyptus, jasmine, kiwifruit, peach, pear, persimmon, plantain, pumpkin, strawberry, tomato, rose and zea mays (corn).
Mills says that since its discovery in California, LBAM "has accumulated a rich set of resident parasitoid species comparable to that seen in its native Australia. However, in contrast to the low levels of parasitism that invasive hosts typically experience from resident parasitoids, parasitism levels for light brown apple moth are very high."
He will discuss, among other things, "the importance of resident parasitoids as barriers to the invasions of light brown apple moth in California."
Plans are to record the seminar for later posting on UCTV. Hosting the seminar is entomologist Mary Louise Flint of the Department of Entomology/UC Statewide Integrated Pest Management Program.
- Author: Kathy Keatley Garvey
It's nice to remember the honey bee on Valentine's Day. You'll see many Valentine cards inscribed with "Bee My Valentine" and featuring a photo of a bee.
Many of those photos depict a queen bee, the mother of all bees in the hive.
To be a queen, she'll need to be fed royal jelly as a larva. The nurses bees feed the otther larvae a regular worker diet that includes pollen.
"Queen larvae are fed royal jelly throughout larval development, providing a nutritional stimulus that causes them to develop into fully functional females with large ovaries," writes apiculturist Norman Gary, emeritus professor of entomology at UC Davis, in his book, Honey Bee Hobbyist: The Care and Keeping of Bees.
"Queens develop from egg to adult in about 16 days," Gary writes. A queen usually lives about two to three years, but most beekeepers re-queen the colony after a year.
In peak season, a queen bee will lay about 2000 eggs--so that's 2000 mouths to feed.
"A few queens live for as long as two or three years, but old queens are a liability to the colony due to diminished egg-laying capacity, a principal cause of reduced colony populations and reduced honey production," Gary says. "Their performance usually diminishes long before they die, similar to humans."
Gary also says in his book that egg-laying capability "is not the only measure of a queen's performance. Queens produce pheromones that greatly affect the activities, especially foraging activity of workers. Pheromone production diminishes in quality and quantity as queens age."
That's something that the Valentine Day cards don't tell you. Neither do they tell you that after a swarm, the first virgin queen to emerge from the series of newly constructed queen cells in the colony will sting her competitors so she can take over the hive.
Or, as Gary writes, "Rival queens engage in fierce stinging attacks until only one virgin queen remains. Virgin queens also initiate the destruction of capped queen cells containing their younger counterparts and sting them before they can complete development. This is the only time queens ever use their stingers."
Not a sweet thought on Valentine's Day!
- Author: Kathy Keatley Garvey
Plants communicate. They do.
Ecologist Richard Karban, a professor in the UC Davis Department of Entomology, points out that one of the simplest forms of communication involves shade.
When a plant is shaded, it grows away from the plant or other object that's shading it.
Today he published research in the Proceedings of the Royal Society B: Biological Sciences that is truly amazing readers. It involves kinship, communication and defenses.
Basically, if you’re a sagebrush and your nearby kin is being eaten by a grasshopper, deer, jackrabbit, caterpillar or other predator, it’s good to be closely related. Through volatile (chemical) cues, your kin will inform you of the danger so you can adjust your defenses.
If you’re not closely related, communication won’t be as effective.
Kin have distinct advantages when it comes to plant communication, just as “the ability of many animals to recognize kin has allowed them to evolve diverse cooperative behaviors," Karban says. For example, fire ants can recognize kin. “Ants will destroy queens that are not relatives but protect those who are."
That ability is less well studied for plants--until now.
“When sagebrush plants are damaged by their herbivores, they emit volatiles that cause their neighbors to adjust their defenses,” Karban said. “These adjustments reduce rates of damage and increase growth and survival of the neighbors.”
“When sagebrush plants are damaged by their herbivores, they emit volatiles that cause their neighbors to adjust their defenses,” Karban said. “These adjustments reduce rates of damage and increase growth and survival of the neighbors.”
“Why would plants emit these volatiles which become public information?” he asked. “Our results indicate that the volatile cues are not completely public, that related individuals responded more effectively to the volatiles than did strangers. This bias makes it less likely that emitters will aid strangers and more likely that receivers will respond to relatives.”
The research, “Kin Recognition Affects Plant Communication and Defense,” is co-authored by two scientists from Japan and two from UC Davis: Kaori Shiojiri of the Hakubi Center for Advanced Research, Kyoto University, and Satomi Ishizaki of the Graduate School of Science and Technology, Niigata University; and William Wetzel of the UC Davis Center for Population Biology, and Richard Evans of the UC Davis Department of Plant Science.
To simulate predator damage, the researchers “wounded” the plants by clipping them and then studied the responses to the volatile cues. They found that the plants that received cues from experimentally clipped close relatives experienced less leaf damage over the growing season that those that received cues from clipped neighbors that were more distantly related.
“More effective defense adds to a growing list of favorable consequences of kin recognition for plants,” they wrote.
The researchers performed their field work on sagebrush (Artemisia tridentata) at Taylor Meadow, UC Sagehen Creek Field Station, near Truckee. They conducted four field experiments over three years “that compared the proportion of leaves that were damaged by herbivores over the growing season when plants were provided with volatile cues clipped from a close relative versus cues from a distant relative,” the scientists wrote.
For closely related kin, they snipped stem cuttings (clones), potted them, and then returned the pots to the field. They determined relatedness “by using microsatellites that varied among individual sagebrush clones.”
The result: “Plants responded more effectively to volatile cues from close relatives than from distant relatives in all four experiments and communication reduced levels of leaf damage experienced over the three growing seasons,” they wrote. “This result was unlikely to be caused by volatiles repelling or poisoning insect herbivores.”
Karban, who has studied plant communication among the sagebrush at the site since 1999, likened the plant communication to neighbors “eavesdropping.” They “hear” the volatile cues of their neighbors as predators damage them.
Eavesdropping. Kinship. Plant communication. Plant defenses.
Fascinating stuff.
Who knew?