Microhabitat segregation of two Utah Sand Dune tiger beetles (Coleoptera: Cicindelidae)

The Coral Pink Sand Dunes tiger beetle (Cicindela limbata albissima) exists only within the Coral Pink Sand Dunes in southwestern Utah. It is currently a candidate for listing as an endangered species. Cicindela tranquebarica occurs throughout the southwestern United States, including the Coral Pink Sand Dunes. We examined microhabitat differences between C. l. albissima and C. tranquebarica. Results of June 1999 adult counts and measurements of percent soil moisture and salt content in 53 interdune swales indicated a significant negative correlation between soil moisture and an index of the relative number of adult C. l. albissima to C. tranquebarica, and a significant positive correlation between soil moisture and direct counts of adult C. tranquebarica. The index of relative number of adults of the 2 species was unrelated to salt content. The relative ratio of larvae of the 2 species in a given swale was significantly correlated to the relative ratio of adults of the 2 species. The cause of the observed microhabitat differences for relatively moist or dry soil could be due to a number of as yet unstudied factors including oviposition preference by the females and larval competition.