Posts Tagged ‘bumblebee’

Pleistocene Pollinators

June 12, 2015

The media sure likes to generate panic.  It must be good for ratings.  Recently, American media outlets offered wall-to-wall coverage of the Ebola virus, a danger that eventually killed 2 or 3 people in the United States from a population of over 300 million.  During slow news cycles the media seems to always find some obscure disease of the month to fill air time.  Another constant well of media anxiety is anthropogenic-influenced climate change, even though its worst effects won’t be felt in our lifetimes, and there’s nothing we can do about it, unless people are willing to give up affordable electricity and cars.  A few years ago, media pundits started peeing in their pants about colony collapse disorder.  Without honeybees (Apis mellifera) they claimed there would be no pollination of fruits, nuts, and vegetables.   The world would have no fresh produce, and we’d be stuck with a boring diet of wind-pollinated grains.  In some regions their fear has come true.  In upstate New York colony collapse disorder wiped out so many honeybees, bee keepers were unable to provide any hives to help pollinate some apple orchards.  There was no loss of production. Orchards produced just as many apples without honeybees as they did with them.  Orchardists realized they’d been duped for decades by bee keepers into thinking they couldn’t grow fruit without paying for the rental of bee hives.

There are 140 species of native leaf cutter bees, including the blue orchard bee (Osmia lignaria), a species that is considered a better pollinator than non-native honeybees.  Moreover, there are many species of native bumblebees, butterflies, and wasps that pollinate flowers.  Native bees are such effective pollinators that honeybees were not missed at all.  As long as some natural areas are left in the vicinity of gardens and orchards, there will always be enough native pollinating insects; and honeybees will be completely unnecessary.  No need to worry about colony collapse disorder–many species of native bees are solitary and don’t nest in colonies.

Osmia-lignaria----WEB

Blue orchard bees are more effective pollinators than honey bees.

Southeastern blueberry bees and bumble bees pollinate my blueberry bushes.

Bumble Bee Queen

Bumblebee (Bombus impatiens)

I marvel at the lack of critical thinking among reporters and media pundits who are so quick to form opinions without realizing how illogical their conclusions are.  Europeans brought honeybees to North America 400 years ago, but before then, Native Americans successfully grew fruits and vegetables dependent upon insect pollination.  They farmed squash, beans, tomatoes, peppers, and plums.  Honeybees are just 1 species out of thousands of insect pollinators in America, yet the media know-it-alls led people to believe a nightmare scenario of no fruits or vegetables.  Not a single pundit during the panic of colony collapse disorder even realized honeybees are a non-native invasive species.  Usually, invasive species are another topic of unnecessary panic frequently reported upon by the media.

Thousands of species of American plants have depended upon insect pollinators for millions of years–ever since the evolution of flowering plants. The fossil record of these insects is scant.  When rare circumstances do occur that preserve ancient insects, the remains are usually so fragmentary they can’t be identified at the species or genera level.  Some nests of a species of leafcutter bee (M. gentillis) were found in the La Brea tar pits, California.  The same species still lives in the region today.  Studies of Pleistocene insects determined individual species adjusted their range according to fluctuating climate cycles, but no known large scale extinctions occurred during this era. (See: https://markgelbart.wordpress.com/2012/07/18/using-fossil-beetle-assemblages-to-determine-temperature-ranges-during-the-late-Pleistocene/) The insect pollinators we find in our yards today are the same species that lived during the Pleistocene.

Reference:

Bjerga, Alan

“Betting on Nature to Solve the Bee Crisis”

Bloomberg Business Week May 18-24, 2015

Blueberry and Bumblebee

May 21, 2012

I have 4 cultivated blueberry bushes.  They usually flower in March, produce fruit in June, and offer lovely red foilage in  fall.  This year, winter ended 2 weeks earlier than normal, and Saturday (May 19th) I harvested my first blueberries.  They were plump from a recent drought-breaking rain.  I made my first batch of blueberry pancakes the following morning.  My bushes give me all the berries I need for pancakes, muffins, and desserts for about a month.

My blueberry bushes flower in February and March.  The bees swarm to them every year.  Without these pollinators there would be no fruit.

Note the bees.  The most common species pollinating the flowers are the southeastern blueberry bees and bumblebees.  The former looks similar to the latter but is smaller.

Two bushes.  Two varieties.  One of the four bushes (not pictured) is stunted and doesn’t produce much yet.

Good plump berries by May 18th.

Blueberry flowers attract several kinds of bees well adapted to late winter/early spring weather conditions.  Because these species of bees are covered with hair, they are able to withstand colder temperatures than most other insects and are among the first arthropods to emerge in early spring.  The black coloring also helps increase their body heat.  The southeastern blueberry bees, bumblebees, and honeybees pollinate over 96% of the blueberry crop in southeastern North America.  The southeastern blueberry bee (Hapropodia laboriosa) is by far the most common type pollinating my bushes.  They look like a small bumblebee and are a solitary species.  The female digs a long burrow in sandy soil and broods her nest in it.  Their lifespan matches the length of time blueberry bushes flower–about 3 weeks.  They are completely dependent upon blueberry bushes, unlike bumblebees (Bombus sp.) which pollinate a much greater variety of plants.  Bumblebees live in colonies of from 200-2000 individuals.  They also nest in burrows where the overwintering queen becomes the sole survivor when hard weather hits.  Both of these native bees are not aggressive.  I’ve never been stung by either one.  One would have to roughly handle one of these species or invade a nest to get stung.

Horticulturalists cultivated high bush blueberries, creating hundreds of varieties, but low bush blueberries only grow in the wild.  Nevertheless, there are such extensive stands of low bush blueberries in Maine that they’re gathered wild and can be found in the frozen food section of many supermarkets.  Low bush blueberries grow wild in my neighborhood, including my front yard.  These ripen in late July/early August but are of disappointing quality compared to my cultivated high bush blueberries.  Euell Gibbons claimed wild blueberries work better in muffins than cultivated ones, but the variety that grows in my neck of the woods is hard and bittersweet.  My wife and daughter love cultivated berries but declined to eat the wild ones after trying them.  Eight species of blueberries are native to the piedmont region of the southeast: sparkleberry (Vaccinium arboreum), black high bush blueberry (V. atroccum), high bush blueberry (V. corynborum), Elliott’s blueberry (V. elliotti), southern low blueberry (V. pallidum), deerberry (V. stamineum), slender blueberry (V. tenellum), and early low blueberry (V. vaccillum).

Blueberries generally grow in colonies and prefer sandy acidic soil.  They thrive in sunny open areas with little to no tree canopy.  They can tolerate a few pine trees which don’t shade them.  They’re another fire adapted plant–underground runners help them resprout following ground fires.  When Euell Gibbons went hunting for blueberries, he’d visit the office of a National Forest ranger and ask him to point out on a map where the most recent burns had taken place.  Native Americans set fire to the woods nearly every year to foster habitat for berries, though this was done for several other reasons as well such as improving habitat for game, eliminating insect and snake refuges, and increasing visibility to avoid being ambushed by other Indians.

Undoubtedly, blueberries were a common component of southern Pleistocene landscapes.  Dynamic factors–sudden climate changes, unchecked wild fires, and megafauna foraging–created highly diverse environments including the open spaces blueberries require.  Pleistocene-aged heath pollen in measurable amounts occurred in Nodoroc, a mud volcano near Winder, Georgia (the central part of the state).  The pollen dated to ~30,000 BP, a brief interstadial immediately preceding the Last Glacial Maximum.  The pollen record here suggests an environment dominated by pine, oak, and grass; though hickory, spruce, and fir were common, while maple, beech, chestnut, and birch were present in this diverse landscape. The presence of high amounts of ragweed, an early successional species, is evidence of an environment in constant flux.  Pine pollen and macrofossils at Nodoroc suggest a mixture of southern species (shortleaf) and northern species (jack, red, and white).  In Maine wild blueberries grow in large barrens and are associated with the northern species of pine mentioned above.  One caveat–the heath family also includes common non-blueberry species such as azalea, mountain laurel, and fetterbush, so it’s likely they contributed to the heath pollen.  Scientists can’t differentiate to the species level when examining heath family pollen.

Pleistocene environments in Georgia may have included vast blueberry barrens such as those occurring in Maine today, especially with large flocks of passenger pigeons spreading the seeds that eventually found ideal habitat.  William Bartram rode his horse through miles of what he referred to as “strawberry plains” in north Georgia and North Carolina.  This environment–common just 200 years ago–is now completely extinct. Strawberries require sunny conditions, just like blueberries.  In the extensive wilderness of the Pleistocene perhaps blueberry barrens and strawberry plains covered miles of territory.

Maine blueberry barren.  This photo must have been taken during fall when the leaves turn red.  The owners of this land burn it often to faciliate the growth of wild blueberries–an uncultivated cash crop. Did Pleistocene Georgia have extensive blueberry barrens such as this?  Or did they just grow in small colonies wherever a fire burned a small section of forest?