Natural History of the Colorado Great Sand Dunes Tiger Beetle, Cicindela theatina Rotger

Pineda, Phyllis; Kondratieff, Boris

The natural history of the Great Sand Dunes tiger beetle, Cicindela theatina Rotger, was studied from 1997 through 2000 at its type locality, the Great Sand Dunes of Saguache and Alamosa counties, Colorado. Cicindela theatina is an endemic insect of the Great Sand Dunes, restricted to suitable habitat within an area of 290 km2 (85.4 mi2). Areas of suitable habitat are characterized by active dunes, sandy blowouts, or shifting sands with vegetative cover between 0.20 and 15.04 percent. The entire life cycle from egg to reproductive adult is estimated at 2.5 years in the field. Reproductive adults are first visible on the dunes in late-May, with mating pairs visible through June. This insect undergoes three larval instars. First instar larvae are apparent during mid June. Second instar larvae are apparently active from July through early August. Third instar larvae are first apparent during mid August, undergo diapause through the winter months, and remain as third instars through the following July. Third instar larvae then pupate and emerge as teneral adults in early to mid August and will commence hibernation during late August or September and remain in diapause until the following may. This species is diurnally active with most observations on warm, sunny days when sand temperatures elevate sufficiently to induce daily activity. Daily activity was classified into six categories, basking, foraging, stilting, shade-seeking, burrowing at mid-day, and burrowing at evening. These behaviors appear to be influeuced by surface temperatures of the sand, and four of these categories (foraging and burrowing at evening excluded), are thermoregulatory behaviors which maintain optimal body temperatures for activity. Although C. theatina is endemic to the Great Sand Dunes, it was found to occupy similar habitats as other Cicindela species. Predators were rarely observed, but it is likely that species of Asilidae (robber flies) and Atherze cuniculnriil (burrowing owl) feed on adults of C. theatina. Predators or parasitoids of larval C. theatina were not observed. There is substantial interest in tiger beetle and sand dune conservation. Three species closely related to C. theatina (C. orenicola, C. albissima and C. columbica) have come under numerous forms of anthropogenic threats resulting in varying levels of protective measures. By virtue of its status Great Sand Dunes was spared such damage; therefore, the habitat for C. theatina remains relatively undisturbed and serves as a model for conservation in sand dune habitats.

Natural History of the Colorado Great Sand Dunes Tiger Beetle, Cicindela theatina Rotger

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