Stephen Buchmann, The Bee Works

Thursday, 25 Sep 2003

TUSCON, Ariz.

“The evidence is overwhelming that wild pollinators are declining around the world. Most have already experienced a shrinkage of range. Some have already suffered or face the imminent risk of total extinction. Their ranks are being thinned not just by habitat reduction and other familiar agents of impoverishment, but also by the disruption of the delicate ‘biofabric’ of interactions that bind ecosystems together. Humanity, for its own sake, must attend to the forgotten pollinators and their countless dependent plant species.”
— Edward O. Wilson, Harvard University, from the foreword to The Forgotten Pollinators

I couldn’t have stated it more presciently. The green biofabric that clothes, protects, heals, and feeds everything on land is coming apart at its seams, unraveling thread by thread as we go about our usual business of taking short-term, ecologically subsidized profits and generally not caring. At the very least, we usually don’t give flowering plants and their codependent pollinators a second thought.

For several hours this morning and for much of the previous couple of weeks, I’ve been informally polling my melittological (the study of bees) colleagues and asking them to weigh in on pollinator extinctions and the general question of rare, threatened, and endangered invertebrates. Everyone seems to agree that we have lost many birds (e.g., many of the curve-billed honey eaters that pollinated the lobelioids Clermontia and Cyanea in the Hawaiian archipelago), and some of the magnificent flying foxes, actually megachiropteran bats, from Samoa and other Pacific Islands. According to entomologists at the Bishop Museum, there may be as many as 77 species of insects that have gone extinct in the Hawaiian Islands. There are also good examples of bee extinctions from European countries, especially the United Kingdom. There are other apparent extinctions of bees from the floristically rich floral province of Western Australia, its wheat belt now a vast monocultured biological wasteland fed upon only by massive combines with insatiable appetites.

The IUCN (World Conservation Union) Red List of Threatened Species lists a total of 557 species of insects as globally threatened in 2002. The same source lists 236 U.S. animals (vertebrates plus invertebrates) as having gone extinct, with a total of 1,499 in threatened and other categories. These and other similarly disturbing statistics have prompted Scott Hoffman Black, executive director of the Xerces Society, to write a number of articles, and Canadian Dr. Peter G. Kevan of Guelph University to head the Task Force on Declining Pollination, a working group of the IUCN’s Species Survival Commission.

What’s clear is that the United States has lost several species or subspecies of butterflies in recent times. The first documented butterfly extinction was the Xerces Blue (Glaucopsyche xerces), the namesake of that society dedicated to invertebrate conservation.

Those I asked were divided, however, about whether we have lost any of our native bees. Along with several Xerces staff members, and a few other “melittophiles,” I’ve set about to find out just how many bees might be so rare or threatened by anthropogenic changes to their habitats that they might be good candidates for listing under the federal Endangered Species Act.

Considering the political and legal mazes confronting those who try to get rare plants or invertebrate animals listed, it amazes me that anyone or any organization is willing to undertake an attempt. The process can take many years, it’s expensive, it’s fraught with hidden dangers, and it seems to raise the hackles on just about everyone.

Land developers in Riverside County in southern California bristle and local politicians brandish fly swatters whenever the videotape is rolling and the federally listed Delhi Sands Flower-Loving Fly (Rhaphiomidas terminatus) is mentioned. Everyone knows that the first federally protected fly stands in the way of hospitals and other instruments of human progress. Why can’t the environmentalists see that? Environmental activists cry foul, and at least one Riverside entomologist has been quoted as saying, “It’s the habitat, stupid.” He’s right, actually.

The Delhi Sands Flower-Loving Fly is a unique product of evolution and has every right to be where it is, but the sad part is that in the name of progress we so readily and so easily give up and sell off precious wildland habitats, which, like an ecological Humpty Dumpty, cannot be reassembled. That humble fly, like so many other pollinators, performs unique and invaluable ecosystem services that we all ultimately depend upon.

Just as the eco-players and consultants who assembled the artificial biomes within Arizona’s Biosphere II — a $200 million experiment of life under glass — found out, it’s not easy playing creator, or natural selection, when designing a world from scratch. Just having some of the bio-ingredients isn’t enough when you don’t have the crucial recipes nor any idea how long to bake your ready-mix world. I know because it was my job to add the bee pollinator “seasoning” ingredients to that biotech world. Eventually, exotic ants, cockroaches, and weedy plants ruled the place. Similar simplifications of habitats and loss of biotic diversity are happening all over the world. Perhaps it’s because we are too arrogant or too naive, thinking that Homo sapiens is ecologically omniscient and can effectively manage any living system given enough committee meetings or money. The truth is that we simply don’t know enough about how all the organisms interact with one another in complex natural ecosystems. What happens when one insignificant fly or a few 4-mm-long nondescript sweat bees go extinct? In an oft-used metaphor, are we losing the biological rivets that are holding our eco-plane together, until too many have been lost and the plane falls from the sky?

Before the Hawaiian Islands were overpopulated with people and their coterie of camp followers, including various feral rats, cats, cattle, wild boar, invasive plants, and others too numerous to mention, they were a showcase of evolutionary adaptive radiations. Few other places on earth can boast such an amazing biota, which had evolved in just a few million years on barren volcanic islands risen from the depths.

Before the arrival of the Polynesian double-hulled canoes, all the islands’ animals and plants were unlikely winners in a biotic long-distance lottery. They had flown, swum, ballooned in the jet stream, or hitchhiked in mud on birds’ feet to get there in the first place. Hawaii is more than 2,000 miles from the nearest continental source area, and only 500,000 years old, the world’s most isolated chain of high islands. Yet from such humble beginnings wondrous forms evolved, including a diverse assemblage of flies in the genus Drosophila (responsible for most of what humankind knows about genetics) and the curve-billed honey-eater birds.

One even less well-known group consists of the 60 species of Hylaeus (Nesoprosopis) bees, the only bees endemic to the Sandwich Isles. These bees have recently been monographed by Drs. Howell Daly and Karl Magnacca. Of the 60 species, at least 11 species have not been collected or seen since 1989 or earlier. The species at greatest risk are the ones that live at the lowermost elevations, habitats that have all but been destroyed by urban sprawl or been overtaken by a choking green blanket of weeds. Some of these lowland inhabiting Hylaeus species are likely extinct.

Other bees on the North American mainland are so rare that they have only been collected once or twice, from the original holotype or other specimens in the type series. What do we do with such species, or the case of errants just crossing the U.S. border in Arizona or Texas from Mexico? In the first case, these bees (like the parasitic bee genera Holcopasites or Oreopasites) may be naturally exceedingly rare across their range, therefore rarely encountered bees on already rarified hosts. In the latter example, some of these rare bees may be fairly common and not automatically threatened in other habitats in northern Mexico.

I personally believe that we have lost not just species of butterflies, but bees as well in the continental United States. In some cases, it will take intensive new multiyear sampling and mining of historical data, the dried pinned specimens in museum unit trays, to find out. In other cases, we may never know because the extinctions likely occurred hundreds of years ago, before anyone noticed. Whatever the expense and the risks, it’s worth such efforts to find out more about the fate of our champion pollinators, America’s native bees.