Kendra Paul E, Montgomery Wayne S, Niogret Jerome, Pruett Grechen E, Mayfield Albert E, MacKenzie Martin, Deyrup Mark A, Bauchan Gary R, Ploetz Randy C, Epsky Nancy D
United States Department of Agriculture, Agricultural Research Service, Subtropical Horticulture Research Station, Miami, Florida, United States of America.
Archbold Biological Station, Lake Placid, Florida, United States of America.
PLoS One. 2014 Jul 9;9(7):e102086. doi: 10.1371/journal.pone.0102086. eCollection 2014.
The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were positively correlated with attraction, and EAG analyses confirmed chemoreception of terpenoids by antennal receptors of X. glabratus.
入侵性的红海湾粉蠹虫（Xyleborus glabratus）是月桂萎蔫病的主要传播媒介，月桂萎蔫病是由共生真菌劳雷拉菲氏菌（Raffaelea lauricola）引起的一种致命疾病。这种疾病已导致美国东南部的红海湾鳄梨（Persea borbonia）和沼泽海湾鳄梨（P. palustris）树大量死亡，威胁到佛罗里达州的鳄梨（P. americana）生产，并且有可能影响其他新大陆物种。迄今为止，北美所有红海湾粉蠹虫的寄主和月桂萎蔫病的易感植物均为樟科植物。这项比较研究结合了田间试验和实验室生物测定，以评估雌性红海湾粉蠹虫对九种樟科植物新鲜砍伐的原木的吸引力和钻孔偏好，这九种植物分别是：鳄梨（每个植物品种的一个栽培品种）、红海湾鳄梨、沼泽海湾鳄梨、丝叶海湾鳄梨（Persea humilis）、加州月桂树（Umbellularia californica）、檫树（Sassafras albidum）、北方香料树（Lindera benzoin）、樟树（Cinnamomum camphora）和披针叶楠（Nectandra coriacea）。此外，还进行了挥发性成分收集和气相色谱 - 质谱联用（GC - MS）分析，以量化试验原木的萜类化合物排放，并进行了触角电位测定（EAG），以测量红海湾粉蠹虫对GC - MS鉴定出的萜类化合物的嗅觉反应。在田间和实验室试验中，各处理之间均观察到显著差异。在田间，丝叶海湾鳄梨和樟树吸引的甲虫数量最多，披针叶楠和香料树吸引的最少，而在丝叶海湾鳄梨、月桂树、沼泽海湾鳄梨和红海湾鳄梨上的钻孔活动最为频繁，在披针叶楠、香料树和樟树上的钻孔活动最少。危地马拉品种的鳄梨比其他品种更具吸引力，但三者之间的钻孔反应相当。结果表明，樟树可能含有一种抑制钻孔的化学物质，并且不同的线索与寄主定位和寄主接受有关。α - 荜澄茄烯、α - 可巴烯、α - 葎草烯和卡拉烯的排放与吸引力呈正相关，EAG分析证实红海湾粉蠹虫的触角感受器对萜类化合物有化学感受。
