Sunday, March 3, 2013

A case for Hawaiian native bee conservation: save the plants!

Hawai`i in the 1800s had abundant natural pollinators in its native yellow-faced bees.

So common were these members of the genus Hylaeus that the great British naturalist Robert C.L. Perkins called them the “most ubiquitous of Hawaiian insects.” Perkins was author of the three-volume “Fauna Hawaiiensis” or “Zoology of the Sandwich (Hawaiian) Isles.”

(Image: Hawaiian yellow-faced bee on  `ilima blossom at Kilauea lighthouse on Kaua`i. Credit: Forest and Kim Starr.)

Perkins identified 52 species of closely related Hawaiian bees. Many of those are now rare and some may be extinct.  Most of us don’t have a clue what they look like: they tend to look waspier than honey bees, tend to be black, with white or yellow markings on the faces. They are solitary and not hiving bees, nesting in the ground or in hollow branches.

Causes of their decline? Probably habitat loss, predation by ants (no ants are native to Hawai`i) and wasps like the Western yellow jacket, and competition with species like honey bees. 

As they declined, their pollination role was partially filled by the imported honey bee. 

Today, modern scientists are arguing that wild pollinators must be protected to assist the pollination by honey bees, which are themselves are under such an onslaught from pests, pesticides and other threats. 

Indeed, in many cases, the original native wild pollinators are more effective pollinators than honey bees, the authors say. 

The paper, “Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance,” has an exceedingly long list of co-authors, from North and South America, Europe, Africa, and the Pacific. It argues that there are “universally positive associations of fruit set with wild-insect visits to flowers in 41 crop systems worldwide.”

Indeed, the authors report that wild insects produce fruit set at a significantly higher rate than honey bees do. 

“Overall, wild insects pollinated crops more effectively, because increase in their visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation,” they wrote.
That argues, they say, to support the health of both honey bee and wild insects to further agricultural goals.

“Our results suggest that new practices for integrated management of both honey bees and diverse wild-insect assemblages will enhance global crop yields,” they wrote.

That will take some work in Hawai`i.

Native bees are so rare today that if you go to modern Hawaiian dictionaries, the only name for bee is related to the honey bee: nalo meli, literally honey fly.  

The Xerces Society, which supports invertebrate conservation, has urged greater attention to the plight of the native bees, and has petitioned the federal government to list several Hylaeus species as endangered.  

The U.S. Fish and Wildlife Service in 2011 determined that endangered species listing is warranted for seven species of Hawaiian bees and that the agency plans to get around to it, but that there are higher priorities now. 

The state Department of Land and Natural Resources has also been studying Hawaiian bees

© Jan TenBruggencate 2013

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