Multiscale assessment of oviposition habitat associations and implications for management in the spotted lanternfly (Lycorma delicatula), an emerging invasive pest

1. 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. 2. 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. 3. 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.
4. 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. 5. Synthesis and
applications. Our results indicate 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.