ENHS Nature Trails April 2002 Article 2

April Musings
by Melody Clarkson

We hear a lot about butterfly gardening these days, and no one can deny the aesthetic rush of spotting a crowd of blues puddling or a lone swallowtail dallying between flowers as he goes about his pollinating business, but I've been noticing a lot of other pollinators: bumble bees in a variety of sizes, flies almost in a fury as they move from cherry blossom to cherry blossom, and of course the hummers . . . . So I did a little dilettante style research and found some really interesting info aboutpollinaton in the January/February 1999 Zoogoer magazine on line . . . a lemur is a pollinator?

With 130,000 to 200,000 species of pollinators, a "typical" pollinator doesn't exist. Beetles, which make up 350,000 named species worldwide, pollinate about 88 percent of all angiosperms (flowering plants). Ants, wasps, and bees collectively pollinate 18 percent. Butterflies and moths pollinate only eight percent of all angiosperms. Although birds and bats and other mammals don't pollinate many species, they are vital for the plants that rely on them for reproduction. As pollinators, bats alone bring us many products, including vanilla, dates, tequila, and bananas.

Plants and pollinators have been evolving together since at least the early Cretaceous period--that's over a 144 million years and includes more than a billion bee generations--and their relationships have become increasingly specialized. Flower color, shape, fragrance, and position attract specific pollinators. For some flowers, timing is everything. Yellow lantana flowers turn a red shade--invisible to butterflies--once the flowers are pollinated in order to concentrate butterfly activity on unpollinated yellow flowers. Scarlet gilia flowers attract hummingbirds with red flowers in early summer and switch to white during late summer in order to attract nocturnal hawkmoths. Pollinators in turn sometimes seek very specific commodities from plants. Males of one butterfly species visit flowers to collect certain alkaloids, a butterfly aphrodisiac of sorts that sends females of the species into a narcotic swoon. When the butterflies mate, the male transfers the chemical to the female's reproductive tract and she coats her eggs with it to protect them from ant attacks according to Adrian Forsythia, an entomologist with the Smithsonian National Museum of Natural History.

Although specialization increases pollinator efficiency, an inherent problem lurks: "Each of the mutualists suffers reproductive failure when the other cannot be found at the right place at the right time," wrote University of Arizona's Buchmann and Gary Nabhan, Director of Science at the Arizona-Sonora Desert Museum, in their book, The Forgotten Pollinators. It makes sense, then, that fewer than one percent of plants rely exclusively on a specific pollinator species, and vice versa. However, in Madagascar, for example, only the black-and-white ruffed lemur is agile enough to open and pollinate the traveler's tree flowers. Without the lemur, the trees couldn't reproduce. But even those species involved in many different mutualistic relationships are vulnerable. Habitat loss, fragmentation, pesticides, and exotic species all jeopardize plant/pollinator relationships.

But that's for another musing, for now I want to be like that female butterfly in a "narcotic swoon" over all that's wonderful about spring. And thanks to Alison Emblidge and Emily Schuster for the use of their article " Saving Pollinators."

Melody Clarkson

Xerces was a small butterfly, the upper wing surfaces iridescent blue-violet in the male, brown in the female. Populations inhabited stabilized sandy sites with rather low-growing vegetation, including the former Lone Mountain Cemetery, thePresidio miliary base (just west of the Naval Hospital and north of Lobos Creek), several locations in the Sunset District (including the western slopes of Twin Peaks), and the Lake Merced area. By the 1930's, the butterfly was restricted to vacantlots. The last known specimens were taken March 23, 1941. by W.H. Lange at the Presidio

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