Drought-Caused Decline and Evidence for Rainfall as the Primary Factor Determining Population Size of Cicindela albissima Rumpp (Coleoptera: Cicindelidae)

This study details the impact of the 2020–2021 southwestern US drought and provides an analysis of the effects of rainfall patterns on the population size of the Coral Pink Sand Dunes tiger beetle (Cicindela albissima Rumpp) in Utah. Adult population size has fluctuated widely since the first annual surveys in 1992, from a low of 558 in 2005 to a peak of 3,459 in 2018, then a decline to 166 in 2021. Monitoring annual rainfall, including the record Southwest drought of 2020, in relation to population size and a correlation analysis of rainfall and adult numbers provided further evidence that rainfall is the primary driver of the population dynamics of this species. Low rainfall during April through June in 2019 and especially 2020 likely reduced recruitment and survival of first-instar larvae. Continuing drought conditions during the summer and fall of 2020 increased mortality of later instars, ultimately resulting in the collapse of the 2021 adult population. Adult population estimates increased to 377 in 2022 and 878 in 2023, suggesting the recovery and resilience of this species.