This project seeks to understand how two invasive insect pests, the woolly adelgid and the hemlock scale, affect eastern hemlock trees. The woolly adelgid has devastated entire forests of hemlock along the east coast of North America, but the hemlock scale -- which is just as common -- has had minimal impact. Although common sense indicates that two pests are worse than one, research suggests the opposite. Intriguingly, trees infested with elongate scale seem somehow protected from the adelgid. Understanding why this happens and whether 'inoculation' with one pest might protect the tree from another type of pest requires understanding how trees defend themselves and respond to attack. Researchers have teamed up on a project that uses a combination of experiments and mathematical models to develop a 'road map' of plant responses to forest pests. Specifically, they will assess how each pest affects plant defenses and nutrient storage.
Given the economic and ecological losses caused by many species of insect pests, it is tremendously important to develop a detailed understanding of how forests are impacted by (and might be protected from) multiple pests. By identifying the response pathway, the results of this study can be applied to other systems to predict the likely impact of multiple herbivores on forest health. This project also provides an opportunity for urban schoolchildren to learn more about nearby forests. The researchers have developed a partnership with SMILE (Science and Math Investigative Learning Experiences), a locally-based group that offers enrichment activities to children from poorly-performing school districts. Graduate students and SMILE staff will work with teachers to develop and implement a year-long educational module on forests and food webs. Funding provided by this award will be used to pay for field trips to local forests to help students learn about these systems and survey hemlocks for the presence of invasive pests.