Abstract
Arctomecon californica, the Las Vegas bear poppy, is a rare plant found only in the eastern Mojave Desert of North America. Because of recent declines in the populations of this endemic plant, conservationists are currently seeking protection for A. californica under the US Endangered Species Act. In this study, we investigated the natural history of A. californica and documented insect visitors potentially pollinating A. californica in Clark County, Nevada. We find that the populations of A. californica fluctuate from year to year, with many populations declining by over 90% from 2021 to 2022. The pollinator communities of A. californica also vary from year to year. In some years, specialist bees in the genus Perdita make up the majority of pollinators, while in other years, generalist bees like Apis mellifera and Hylaeus dominate. Furthermore, we confirm what previous work has suggested, that A. californica requires pollinators to set seed, yet not all insect visitors are good pollinators. This work provides useful natural history information about the Las Vegas bear poppy, which will be informative to conservationists designing strategies to protect this imperiled species.