Host plant choice in the frosted elfin, Callophrys irus (Lepidoptera: Lycaenidae)

Suitable habitat for organisms consists of open access to important and essential resources, such as light and nutrients for plants, and food and nesting sites for animals. While these resources may be physically present in a habitat, they may not always be accessible to the organisms that need them to survive. A study investigating host plant choice by the rare frosted elfin butterfly, Callophrys irus, was conducted at Ralph E. Simmons Memorial State Forest in northern Florida in the spring of 2010. Resource use was measured by conducting surveys of the larval host plant, sundial lupine, Lupinus perennis. Occupancy by eggs and larvae and presence of larval feeding damage were recorded and compared to host and non-host vegetative characteristics such as sundial lupine density and grassy, herbaceous, and woody plant cover. Statistical analysis using logistic regression revealed lower occupancy of sundial lupine where non-host plant cover was high, and highest occupancy where non-host plant cover was low to intermediate. The low occupancy of host plants that were densely surrounded by vegetation suggests that factors such as apparency, quality, or access may influence oviposition preference. Reduced occupancy from increased nearby vegetation has important effects on the population at this site, and management should take into account non-host plant crowding of sundial lupine in order to preserve and promote this population of a rare butterfly.