Ozark Baltimore Checkerspot Euphydryas phaeton ozarkae (Nymphalidae) Oviposition Selection Favors More Vigorous Hosts

Abstract

Oviposition search behaviors and host-plant selection play a critical role in the individual and population success of phytophagous insects. These characters are particularly important for specialists and metapopulations. The Ozark Baltimore Checkerspot Euphydryas phaeton ozarkae (Masters 1968) Nymphalidae specializes on Smooth Yellow False Foxglove Aureolaria flava (L. 1753, Farwell 1918) Orobanchaceae and has a metapopulation structure. We examined oviposition search behaviors of E. p. ozarkae using many of the same variables from a study on the nominate subspecies, the Baltimore Checkerspot Euphydryas phaeton phaeton (Drury 1773). Insight into host selection was obtained by comparing characteristics between plants with and without egg masses. Relationships among habitat conditions (and management therein) and the most selected plant characteristics were also determined. We found E. p. ozarkae to be highly selective of oviposition plants, expressing higher values associated with host-plant searching than E. p. phaeton. Butterflies consistently oviposited on plants with the greatest height, area, number of stalks, and number of leaves within a given study site. As average plant vigor increased, however, selection of the highest character values converged and became less prominent. In general, important plant characters were greater in habitats with a more open understory and canopy, which were associated with routine fire management. Continued habitat restoration in the Ozark and Boston Mountain regions and perpetual maintenance using prescribed fire (as appropriate seasonally) may positively affect the Ozark Baltimore Checkerspot by improving plant characters selected by these butterflies.