| Title: | Two invasive herbivores on a shared host: patterns and consequences of phytohormone induction |
| Author(s): | Schaeffer RN; Wang Z; Thornber CS; Preisser EL; Orians CM; |
| Address: | "Department of Biology, Tufts University, Medford, MA, 02155, USA. robert.schaeffer@wsu.edu. Department of Entomology, Washington State University, Pullman, WA, 99164, USA. robert.schaeffer@wsu.edu. Department of Biology, Tufts University, Medford, MA, 02155, USA. Department of Biological Sciences, University of Rhode Island, Kingston, RI, 02881, USA. Department of Natural Resources Science, University of Rhode Island, Kingston, RI, 02881, USA" |
| DOI: | 10.1007/s00442-018-4063-0 |
| ISSN/ISBN: | 1432-1939 (Electronic) 0029-8549 (Linking) |
| Abstract: | "Herbivore-induced changes in host quality mediate indirect interactions between herbivores. The nature of these indirect interactions can vary depending on the identity of herbivores involved, species-specific induction of defense-signaling pathways, and sequence of attack. However, our understanding of the role of these signaling pathways in the success of multiple exotic herbivores is less known. Eastern hemlock (Tsuga canadensis) is attacked by two invasive herbivores [elongate hemlock scale (EHS; Fiorinia externa) and hemlock woolly adelgid (HWA; Adelges tsugae)] throughout much of its range, but prior attack by EHS is known to deter HWA. The potential role of phytohormones in this interaction is poorly understood. We measured endogenous levels of phytohormones in eastern hemlock in response to attack by these invasive herbivores. We also used exogenous application of methyl jasmonate (MJ) and acibenzolar-S-methyl (ASM), a salicylic acid (SA) pathway elicitor, to test the hypothesis that defense-signaling phytohormones typically induced by herbivores could deter HWA. Resistance to adelgid attack was assessed using a behavioral assay. Adelgid feeding significantly elevated both abscisic acid (ABA) and SA in local tissues, while EHS feeding had no detectable effect on either phytohormone. HWA progrediens and sistens crawlers preferred to settle on ASM-treated foliage. In contrast, HWA crawlers actively avoided settlement on MJ-treated foliage. We suggest that induction of ABA- and SA-signaling pathways, in concert with defense-signaling interference, may aid HWA invasion success, and that defense-signaling interference, induced by exotic competitors, may mediate resistance of native hosts" |
| Keywords: | Animals *Hemiptera *Herbivory Plant Growth Regulators Species Specificity Tsuga Abscisic acid Adelges tsugae Fiorinia externa Salicylic acid Tsuga canadensis; |
| Notes: | "MedlineSchaeffer, Robert N Wang, Zhou Thornber, Carol S Preisser, Evan L Orians, Colin M eng NSF-DEB 1256769/National Science Foundation/International NSF-DEB 1256826/National Science Foundation/International Germany 2018/01/25 Oecologia. 2018 Apr; 186(4):973-982. doi: 10.1007/s00442-018-4063-0. Epub 2018 Jan 23" |
