OverviewReconstruct the daily activities of a Great Sand Dunes Tiger Beetle using field notes, graphs, and temperature data.
Reconstruct the daily activities of a Great Sand Dunes Tiger Beetle using field notes, graphs, and temperature data.
You may have seen islands surrounded by a sea of water before, but have you seen a sand island surrounded by a sea of vegetation? If you have visited Great Sand Dunes you have. In this special way, the dunefield of Great Sand Dunes is a sand island isolated by hundreds of square miles of vegetation. Although a few smaller dunefields can be found east of Colorado's Front Range, to find other expanses of dunes, you will need to travel to Utah, southern New Mexico, or western Nebraska. Great Sand Dunes is the only major dune system in this area. Because of their isolation from other sandy habitats, several species of sand-loving insects are found at Great Sand Dunes and nowhere else in the world.
Even if these endemic insects tried to go live in other places, they wouldn't be able to fly far enough to find a suitable sandy home-with a suitable mate! This is their only home, unless the climate changes and sandy corridors bridge the gap by linking Great Sand Dunes with dunefields elsewhere.
How did these insects get here in the first place? Sometime during the last Ice Age, there may have been more habitat for sand-loving insects than there is today. Although it was colder, it may also have been drier for long periods of time. This allowed more dunefields to exist in North America. But when the climate warmed about 13,000 years ago, rain fell more often and the great expanses of open sand dunes became smaller and vegetated. Bare fields of sand became more isolated. In the San Luis Valley, one extremely sand-loving species of tiger beetle was cut off from its relatives and, over time, became just a bit more specialized (and different) than its closest relative. At least that's the theory of why the Great Sand Dunes Tiger Beetle and a number of other endemic insects are found only at Great Sand Dunes.
Recently, researchers have studied the life history of one of these endemic insects-the Great Sand Dunes tiger beetle, known to scientists as Cicindela theatina. They spent a number of summers studying the behavior and habitat preferences of C. theatina. Some of the details of their research are available in the Field Notes at right.
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