Once free to flit over millions of acres of unmolested prairie, the humble Dakota skipper's range has been drastically reduced over time. It was relatively easy in the 1970s for Robert Dana to find the Dakota skipper (Hesperia dacotae), a pollinator that clings to scattered remnants of native prairie that provide its habitat. "It wasn't difficult to find," he said. "If you could find the prairies you could find the butterfly." Dana, an ecologist with the Minnesota Department of Natural Resources, shifted his attention from butterflies to plant species for about 20 years, ending in the mid-2000s. As recently as 2008, when Dana's studied gaze returned to the Dakota skipper, he still found large numbers of the butterflies.
But in the years since, for reasons nobody knows for certain, the Dakota skipper has become an elusive grassland insect, considered threatened by the U.S. Fish and Wildlife Service and endangered by the Minnesota Department of Natural Resources. The shrinking size of its natural domain helps explain the butterfly's population losses, but it's not the whole story.
"Is something else going on in addition to this habitat loss?" said Marissa Ahlering, a prairie ecologist for The Nature Conservancy. "That's kind of the big unknown. What's happening?" Although the reason for the sharp decline of the Dakota skipper remains a mystery, suspicion falls heavily on pesticides, which drift onto remnants of native prairie from surrounding cropland.
The Minnesota Zoo, for instance, has tested grasses from several native prairies and found pesticide residue.
Source: In Forum, June 28, 2016
http://www.inforum.com/news/4063926-why-dakota-skipper-butterfly-disapp…
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