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Dr. Jordan Marshall
Department of Biology
Indiana University – Purdue University Fort Wayne
Emerald ash borer (EAB) has caused significant decline of North American ash trees (Fraxinus spp.), negatively impacting northern forests ecosystems, as well as urban and suburban neighborhoods. Since EAB was introduced from Asia in the 1990’s, a substantial number of ash have succumb to infestation, leading to high mortality rates in Northern America. However, select trees have survived infestation, even though signs of EAB attack are present. This indicates that there is some mechanism by which these specific trees are able to overcome EAB attack and continue to grow vigorously. Because EAB larvae feed on phloem, the ability to regrow phloem and repair injuries is imperative to ash resilience. Following emergence, EAB adults require maturation feeding, which may assist in suitable host finding for subsequent oviposition. The amount of leaf area consumed by EAB adults was compared between leaves from trees identified as low tolerance and high tolerance to attack. Freshly collected green ash leaves were exposed to caged adult pairs (F:F, F:M, and M:M). After pooling the data, we found that significantly more low tolerance leaf area was consumed compared to high tolerance. This result suggests that EAB adults feed preferentially on leaves from low tolerance trees. Leaves from low and high tolerance trees were analyzed for nutrient, water and fiber content. High tolerance trees had a higher boron, magnesium, calcium and iron content. Greater quantities in leaf nutrients may indicate increased defense against attack, vigor and resources for growth and repair, or a combination of such factors. Preferential feeding by adult EAB may provide suitable host identification by the beetles in relation to potential larval success.
Biology | Life Sciences
Smith, Cecelia, "Nutrient Content Compared Between Trees with Low and High Tolerance to Emerald Ash Borer" (2015). 2015 IPFW Student Research and Creative Endeavor Symposium. 63.