Native leaf‐tying caterpillars influence host plant use by the invasive Asiatic oak weevil through ecosystem engineering

Abstract

Abstract. We tested the effect of leaf-tying caterpillars, native ecosystem engineers, on the abundance and host feeding of an invasive insect, the Asiatic oak weevil, Cyrtepistomus castaneus (Roelofs). Leaf quality was previously thought to be the sole factor determining host use by C. castaneus, but adult weevils congregate in leaf ties made by lepidopteran larvae (caterpillars). Adult weevil abundance was naturally higher on Quercus alba and Q. velutina compared to four other tree species tested (Acer rubrum, Carya ovata, Cornus florida, and Sassafras albidum). These differences were associated with more natural leaf ties on the two Quercus species. In the laboratory, weevils fed on all six species but again preferred Q. alba and Q. velutina. When artificial ties were added to all six tree species, controlling for differences in leaf-tie density, adult weevil density increased on all six tree species, damage increased on all species but A. rubrum, and host ranking changed based on both abundance and damage. We conclude that leaf ties increase the local abundance of C. castaneus adults and their feeding. Thus, these native leaf-tying caterpillars engender the success of an invasive species via structural modification of potential host plants, the first described example of this phenomenon.

Declines and Resilience of Communities of Leaf Chewing Insects on Missouri Oaks Following Spring Frost and Summer Drought

“…At Cuivre River State Park (CRSP) in east central Missouri, we have been studying the impact of lepidopteran larvae that silk together neighboring leaves, leaf blade to leaf blade, to form a leaf tie, on the resulting secondary inhabitants of these leaf ties (Lill and Marquis, 2003;Lill, 2004;Marquis and Lill, 2010;Reinhardt, 2011;Wang et al, 2012;Baer and Marquis, 2014). There are 15 species of Lepidoptera at CRSP that construct leaf ties.…”

Ecosystem engineering by a gall‐forming wasp indirectly suppresses diversity and density of herbivores on oak trees

“…Recent work has begun to examine the effects of habitat engineering at community scales that encompass species that do and do not interact directly with the habitat modifications. For example, leaf shelters formed by leaf‐tying caterpillars increase diversity of arthropods at the scale of entire trees, which themselves are mosaics of engineered leaf shelters and unmodified foliage (Lill and Marquis , Baer and Marquis ). This increased diversity, however, is limited to the recruitment of leaf shelter specialists to leaf shelters, with no consistent effects of leaf shelters on the arthropod community that uses unmodified leaves.…”

Comparing the responses of larval and adult lepidopteran communities to timber harvest using long-term, landscape-scale studies in oak-hickory forests

“…Microlepidoptera should not be ignored, however, if the resources are available to sample and identify them. They can be major pests and play important roles in forest food webs (Lill and Marquis, 2003;Baer and Marquis, 2014).…”