I need to start this column with a confession. I’ve never actually seen the animal that I’m about to write about. My neighbors have, and they’ve shown me the evidence of its presence: neat, cylindrical holes in the outer beams and siding of their homes drilled by an insect known as the carpenter bee.

With more than 3,000 species of bees in North America alone, the diversity of life cycle, appearance and behavior of bees is simply enormous.

So, I consulted on this column with an entomologist friend, Andrew Creed of Newburyport, Mass., who has an extravagant fondness for our native pollinating insects.

Carpenter bees are big black bees, the size of a bumblebee. They can be fearsome to encounter outside. The males, who don’t have stingers and can’t hurt you, appear to be curious about humans, often swooping in to get a closer look, a maneuver with an alarming resemblance to dive-bombing.

A fun way to distract an inquisitive male is to toss a bee-sized pebble — they’ll chase it, thinking it is another bee. The female has a stinger, but rarely attacks.

Carpenter bees are solitary insects; unlike honey bees, they do not form colonies. Rather, in the spring, each female carpenter bee prepares her nest by excavating a neat round hole in almost any soft wood — cedar, pine and fir trees, structural timbers, fence poles, lawn furniture, wood siding, you name it. Some sun exposure to keep the nest nice and warm also helps. They will also use old nest holes whenever possible, since constructing these tunnels takes time and energy. Unlike carpenter ants, carpenter bees don’t eat the wood, feeding upon nectar and pollen instead. Their tunnels can extend from inches to feet into wooden structures; new tunnels are often added to old ones, and multiple bees, with separate “apartments,” will sometimes share a common entrance.

Once the tunnel has been dug, the female forms a series of brood cells by depositing a lump of pollen and nectar at one end of a cell, lays an egg on this food ball, and then blocks off the cell with a plug of chewed-up wood. She’ll lay from six to 10 eggs and then die.

The eggs soon hatch into larvae, which feed on the pollen/nectar ball, metamorphose into pupae and then into adults. The new adults chew their way out of the brood cells and out of the tunnels, usually emerging in late August. Just in time for all those late-summer wildflowers. These newly emerged adults spend the rest of the summer feeding and storing pollen in their old tunnel, using the tunnel as a hibernaculum for the winter.

The following spring, the adults emerge, mate, lay their eggs and die, completing the cycle.

The reason my neighbors introduced me to carpenter bees in the first place was to find out how to keep them from burrowing into their houses without having to resort to poisons and other forms of insect murder. The safest, most humane way to keep these bees from choosing your home for their home is to paint any exposed wooden surface. If bees still burrow, you may have to resort to use of a stronger barrier — screening or flashing under the paint. You can also lure bees to other sites by propping up alluring bare wood in various locations around your property.

For my part, as the end of August approaches, I look forward to finally seeing a carpenter bee. That old maxim “the more you learn, the less you know” is so true. There is such a wonderful diversity of plant and animal life in our back yards just waiting for us to open our eyes and discover it.

Sue Pike of York has worked as a researcher and a teacher in biology, marine biology and environmental science for years. She teaches at York County Community College and St. Thomas Aquinas High School. She may be reached at spike@maine.rr.com.

http://www.seacoastonline.com/apps/pbcs.dll/article?AID=/20080813/LIFE/808130348/-1/rss08

Pesticides blamed for bee massacre

Situation in Italy approaching critical levels, expert says

(ANSA) - Rome, July 30 - The widespread use of pesticides is decimating Italy’s honeybee population and costing millions of euros in lost crops, beekeepers and farmers warned on Tuesday. The Union of Italian Beekeepers (UNAAPI) and leading agricultural association Coldiretti both sounded the alarm over a mass die-off among Italian bees over the last year that would cost farmers 2.5 billion euros. Referring to a ‘’silent epidemic'’, UNAAPI said between 40% and 50% of Italy’s honeybees had vanished since the start of last year. ‘’A group of comparatively new pesticides called neonicotinoids are killing the bees,'’ said UNAAPI President Francesco Panella. ‘’These substances were irresponsibly authorized by public powers that bowed to pressure from the chemical industry'’.

Recalling that Italian agriculture uses over a third of all pesticides applied in Europe, he added: ‘’Bees are extremely fragile. ‘’They are excellent indicators of levels of toxicity in the environment. What they tell us should be taken on board with great concern for the survival of future generations'’. UNAAPI accepts that drought and disease have also played a role in the mysterious die-off but insists that the key suspect is a seed treatment using neonicotinoids, an artificial form of nicotine.

A number of studies have linked neonicotinoids to die-offs in bee colonies. Some have suggested the insecticide leads bees to stop feeding larvae and results in a breakdown of their navigational abilities.

Although scientific conclusions have been mixed, Germany banned the use of all neonicotinoid-based pesticides two months ago, while France imposed strict limits on their use on bee crops following mass die-offs in the 1990s.

The pro-technology agricultural association FUTURAGRA, however, rejected claims that neonicotinoids were to blame and stressed that banning the new pesticide would cause serious harm to maize harvests.