Colony Collapse Disorder

Are native bees suffering the same colony collapse disorder as honeybees?
Q: Are native bees suffering the same “colony collapse disorder” as honeybees? [Linda, San Ramon]

A: Colony collapse disorder, or CCD, has gotten a lot of media attention, and with good reason. The western honeybee (Apis mellifera) is native to Europe, Africa, and western Asia and was brought from England to Virginia in 1622. The bees, known to some Indians as “the white man’s fly,” readily escaped and spread on their own to the Great Plains. Their progress west was stopped by the Rocky Mountains, until hives were shipped to California during the Gold Rush.

Honeybees are now a major workhorse (er, make that work-insect) for Big Agribusiness and therefore the rest of us. Crops pollinated by honeybees in the United States are worth over $15 billion a year. Every February bees are trucked or flown in from all over the country and even Australia to pollinate California’s almond trees. So when millions of bees disappear, everyone takes notice, including the National Academy of Sciences and the U.S. Congress.

CCD seems to affect only certain commercial beekeepers, who reported bee die-offs of 30 to 70 percent last year! (Organically kept bees and feral hives do not suffer CCD.) Many causes have been suggested-malnutrition, pathogens, immune problems, mites, genetically modified crops, fungi, pesticides, antibiotics, long-distance transport, and electromagnetic radiation, including from cell phones. The last one got a lot of airtime: Use a cell phone, kill a bee. But there’s little evidence to support that. Some sort of immune system collapse is more likely.

Honeybees aren’t the only game in town, however. Native bees are also significant pollinators of food crops. While they are mostly solitary or form only small colonies, California natives are actually more versatile and effective pollinators than honeybees. Mason bees and bumblebees are active when honeybees are not, such as early in the spring and on cold days, and they are more effective at pollinating tomatoes, cranberries, and potatoes. And flowering plants have evolved for the last 100 million years with their respective insect pollinators, so native bees and native plant life cycles tend to coincide.

There are at least 1,600 native bee species in California, according to our resident expert, UC Berkeley’s Gordon Frankie. He says they are not suffering from CCD, but populations are declining due to habitat loss and pesticide use. Agricultural agencies and organic farmers are beginning to recognize native bees’ value. There are many ways to attract native bees: Creating good nesting sites, planting native flowers, reducing pesticide use, and protecting wild habitat all tend to increase the diversity and number of our native bees.

Michael Ellis – Ask the Naturalist – Bay Nature Magazine

Which Birds Mate for Life

Q: Do any local breeding birds mate for life? Why? [Leo, San Francisco]

A: Some local birds do form long-lasting pair bonds of several different kinds. Ravens and scrub jay pairs hang out together all year, not just at breeding time. Wrentits and resident Canada geese also have long relationships that can last more than ten years.

Most songbirds have the same mate every spring, but this has more to do with site fidelity than with long-term partnership. Males usually arrive early and use songs and displays to define, control, and defend the same territory each year. If a female arrives and finds the same male, courtship ensues, copulation follows, and both tend to the young. But if last year’s male lost his territory, then the new guy will do just fine. So real estate is more important than individuals. But there is a direct correlation between fitness and the ability to secure good territory.

Most of the 12 seabird species that breed in our region mate for life. But it’s fidelity to territory, not to individuals.

Scientists are discovering through DNA analysis that pair bonding does not mean complete faithfulness. There is a lot of cheating going on. The proper term for this is —extra pair copulation,— and both males and females do it. This may increase the genetic diversity and therefore the viability of the offspring. But we are far from understanding the complexities of avian sexual relations.

The evolutionary bottom line is how many thriving offspring you leave behind. There are successful species of birds that mate for life or for a season or for one copulation. Each strategy works for whatever species uses it.

Michael Ellis – Ask the Naturalist – Bay Nature Magazine

Crawdads

Q. A group of families go out every year, often catching up to 300 crawdads for a big feast, releasing those with eggs. We often wonder if we are depleting the supply. How long do crawdads live? Are they native to the Bay Area? -Sam,

Well, Sam I am here to tell you go right ahead and eat all the crawdads you want, with or without eggs. And you can do so completely guilt free. In fact, your annual feast is likely benefiting some native species, such as the California newt. Depending on where you have been catching the crawdads, they could either be red swamp crayfish (Procambarus clarkii) or signal crayfish (Pacifastacus leniusculus). Neither is native to the Bay Area and both are considered invasive pests. The Bay Area native sooty crawdad (Pacifastacus nigrescens) has actually disappeared due to competition from the signal. California now has only one native crayfish — the Shasta crawdad. Native to Shasta County, it is listed as endangered because of water diversions, predation, and competition from that nasty signal crawdad.

The red swamp crawdad, native to the southeastern US, has been transplanted all over the world from Sweden to Kenya as a food source. It is extremely adaptable to a wide range of conditions and is very common in the Delta and Central Valley. Researchers have found that it preys on native California newts and it has been implicated in the disappearance of these amphibians from streams.

Both of these introduced crawdads eat a wide variety of plant and animal matter and can live from five to ten years in the wild. They have also become an important food item for California river otters, herons, egrets, raccoons, and occasionally Sam and his family.

Michael Ellis – Ask the Naturalist – Bay Nature Magazine

Most Rain in the SF Bay area

Q–Which spot in the nine-county Bay Area gets the most yearly average rainfall (and why) and which spot gets the least (and why)? And, of course, how much in each case?

Nearly all of the precipitation that we receive comes between November and April in the form of rain from moisture-bearing clouds off the Pacific. The San Francisco Bay area is well-known for its many micro-climates. Folks at the beach are freezing as the fog lingers in the Sunset District while others are sweltering in the bright sun in Livermore. The distribution and amount of rain is also all over this proverbial map.

At the Pt. Reyes Lighthouse, sticking way out into the ocean, you might expect rain to be plentiful. Wrong. Average rainfall there is only 15 inches. As storm clouds move inland and begin to rise up over the coastal mountains, the air cools. When air cools it cannot hold as much moisture and rain occurs. This is known as orographic precipitation and results in Kentfield getting 48 inches of rain per year from the same storms. And on the back side of these mountains rain shadows exist. So the city of San Jose may only average 16 to 20 inches of rain.

So the bottom line is that Mt. Tamalpais and the Santa Cruz mountains may get 45+ inches, Petaluma and San Francisco 23 inches and Livermore and Tracy 15 or less inches.

Michael Ellis – Ask the Naturalist – Bay Nature Magazine

Last Volcanic Eruption in the SF Bay area

Q: When was the last volcanic eruption in the Bay Area? Where was it?

A: You can easily visit the 10-million-year-old Sibley Volcano (see Bay Nature, April-June 2005) in the hills above Oakland. And I often see college geology classes stopped at the base of the Nicasio Dam in West Marin looking at pillow basalt lava that erupted from the floor of the Pacific Ocean over 100 million years ago.

But for the most recent local volcano, travel north to the 4,200-foot Mount Konocti near Clear Lake. It ceased erupting just 10,000 years ago-a geologic blink of an eye. Konocti (Pomo for “Mountain Woman”) is in the Clear Lake volcanic field, which has been active for at least 2 million years. The field is part of the larger San Andreas Fault complex, and the magma here fuels the largest geothermal energy production field in the United States-the Geysers Complex, in northeastern Sonoma County.

Michael Ellis – Ask the Naturalist – Bay Nature Magazine

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