Multiscale assessment of oviposition habitat associations and implications for management in the spotted lanternfly (Lycorma delicatula), an emerging invasive pest.
Control of incipient invaders-established invasive species in the early stages of spreading-can be inhibited by incomplete knowledge of the species' habitat use. By identifying consistent habitat associations for incipient invaders early, control efforts can be more effective. Yet, because habitat associations are the result of multiscale processes, approaches are needed for integrating data collected across scales to identify them. We employed a hierarchical, multiscale approach to identify oviposition habitat associations in the spotted lanternfly (Lycorma delicatula), an incipient invasive species of high concern in the United States. We targeted four oviposition habitat spatial scales most likely to be used by lanternflies and the spatial scales of explanatory habitat variables most easily used by managers to locate egg masses to control. Spotted lanternflies exhibited oviposition habitat associations at the landscape, site, and tree scales. Overall, lanternflies oviposited more frequently at sites and on trees with low canopy cover in the surrounding landscape indicating higher use of human-impacted habitat. Additionally, they oviposited more frequently on trees from the Acer genus and in the crowns of larger trees beyond the reach of managers without special equipment. The duration a site had been invaded had opposing effects on oviposition at the site and tree scales. Despite high variation in the number of eggs per egg mass, no habitat variables explained this variation, suggesting more work is needed to understand spotted lanternfly reproductive output. Synthesis and applications: Our results indicate that a multiscale approach is needed for spotted lanternfly control with unique strategies for locating egg masses at sites and on trees that vary in invasion duration. Specifically, at younger sites at the invasion edge, managers should expect patchy colonization of sites, yet when a site is colonized, many trees will have egg masses. Comparatively, older sites at the invasion core are more likely to have egg masses present, yet often at a lower density, which may make them difficult to find on individual trees. Based on our results, we assert that multiscale investigations of habitat associations would likely inform the control of other incipient invasive species as well.