Replication Data for: Phytoplasma infection of a tropical root crop triggers bottom-up cascades by favoring generalist over specialist herbivores

We tested the hypothesis that a Candidatus Phytoplasma causing cassava witches’ broom (CWB) on cassava (Manihot esculenta Grantz) is altering species composition of invasive herbivores and their associated parasitic hymenopterans. We conducted observational studies in cassava fields in eastern Cambodia to assess the effect of CWB infection on abundance of specialist and generalist mealybugs (Homoptera: Pseudococcidae), and associated primary and hyper-parasitoid species. Fields were selected as follows: Chetborey, Changchrong (12.58275°, 106.07681°), Chetborey, Sambuk (12.64369°, 106.06290°), Prakprosab, Bang Liegh (12.35089°, 105.98528°), Snoul (12.02920°, 106.40232°). Within each site, we selected one field with high (>20%) and one field with low (0-5 %) incidence of CWB, as determined by assessing the presence of plants with typical symptoms of CWB infection (i.e., stunting, leaf yellowing, leaf and petiole proliferation). We randomly sampled four mealybug-infested plants without CWB symptoms from each field, and an additional four mealybug-infested CWB-symptomatic plants from plots with high CWB incidence (N=64; total number of samples). For each plant, we recorded infestation levels of Phenacoccus manihoti, Paracoccus marginatus, Ferrisia virgata and Pseudococcus jackbeardsleyi. Next, plant samples were transferred to a field laboratory, and kept until emergence of all parasitoid (and hyperparasitoid) wasps.

本研究旨在验证如下假说：感染木薯（Manihot esculenta Grantz）并引发木薯丛枝病（cassava witches’ broom, CWB）的候选植原体（Candidatus Phytoplasma），会改变入侵性植食性昆虫的物种组成及其伴随的寄生性膜翅目昆虫类群。本研究在柬埔寨东部的木薯种植田开展观测研究，以评估CWB感染对专食性与广食性粉蚧（同翅目：粉蚧科，Homoptera: Pseudococcidae）的种群丰度，以及相关的初级寄生蜂和重寄生蜂物种种群的影响。
试验田选取如下：柴波雷（Chetborey）境内的昌荣（Changchrong，坐标12.58275°，106.07681°）、柴波雷境内的桑布克（Sambuk，坐标12.64369°, 106.06290°）、普拉克普罗萨布（Prakprosab）境内的邦利厄（Bang Liegh，坐标12.35089°, 105.98528°）以及斯努（Snoul，坐标12.02920°, 106.40232°）。在每个试验地点，我们各选取1块CWB发病率较高（>20%）和1块发病率较低（0~5%）的田块，发病率通过观察是否存在CWB感染的典型症状植株判定，具体症状包括植株矮化、叶片黄化、叶片与叶柄簇生。
我们从每块田块中随机采集4株未表现CWB症状但受粉蚧侵染的植株；在CWB发病率较高的田块中，额外采集4株表现CWB症状且受粉蚧侵染的植株，总计采集样本64份。针对每株植株，我们统计了木薯绵粉蚧（Phenacoccus manihoti）、番木瓜绵粉蚧（Paracoccus marginatus）、条纹绵粉蚧（Ferrisia virgata）以及杰克贝德氏粉蚧（Pseudococcus jackbeardsleyi）的侵染程度。随后将植株样本转移至田间实验室，保存至所有寄生蜂（及重寄生蜂）成虫全部羽化。