Cooper W Rodney, Spurgeon Dale W
USDA-ARS-Shafter Cotton Research Station, 17053 North Shafter Ave., Shafter, CA 93263, USA.
Environ Entomol. 2013 Oct;42(5):967-72. doi: 10.1603/EN13052.
Despite numerous studies examining feeding injury to cotton (Gossypium spp.) caused by different stages of Lygus hesperus Knight, no consistent trends are apparent. One explanation for inconsistencies among previous results is failure to account for important sources of biological variation. Because it was only recently recognized that feeding behavior and injury differed among adults of different physiological ages, this source of variance was not controlled in earlier studies of Lygus stage-dependent injury. We incorporated this knowledge into video assays and greenhouse experiments to compare feeding behaviors, within-plant distributions, and injury to cotton plants among L. hesperus nymphs and prereproductive adults. Laboratory behavior assays indicated third instars exhibited more stylet-probes, but of shorter duration, compared with prereproductive adults. Numbers and duration of stylet-probes by fifth instars were intermediate to those of third instars and adults. Total time spent stylet-probing was similar among the insect age-classes. On whole plants, third instars tended to reside within the bracts of squares (flower buds) >3 mm in diameter, whereas fifth instars and adults tended to frequent the plant terminals. Adults were more likely than third or fifth instars to be located off the plants at any given observation. Plants exposed to fifth instars exhibited more square abscission and retained fewer squares 3-6 mm in diameter than did plants exposed to third instars or adults. Our results indicated that fifth instars were more injurious to cotton than third instars or prereproductive adults, and that differences in feeding injury corresponded with within-plant distributions exhibited by different L. hesperus age-classes.
尽管有大量研究考察了西方盲蝽（Lygus hesperus Knight）不同发育阶段对棉花（棉属植物）造成的取食伤害，但并未发现明显的一致趋势。先前研究结果不一致的一个原因是未能考虑到生物变异的重要来源。由于直到最近才认识到不同生理年龄的成虫取食行为和伤害存在差异，在早期关于西方盲蝽阶段依赖性伤害的研究中，这一变异来源并未得到控制。我们将这一知识纳入视频分析和温室实验中，以比较西方盲蝽若虫和未成熟成虫在棉花植株上的取食行为、植株内分布情况以及对棉花植株的伤害。实验室行为分析表明，与未成熟成虫相比，三龄若虫表现出更多的口针穿刺，但持续时间较短。五龄若虫口针穿刺的次数和持续时间介于三龄若虫和成虫之间。不同虫龄的昆虫口针穿刺总时长相似。在整株植物上，三龄若虫倾向于栖息在直径大于3毫米的棉蕾苞叶内，而五龄若虫和成虫则倾向于频繁出现在植株顶端。在任何给定观察时刻，成虫比三龄或五龄若虫更有可能不在植株上。与暴露于三龄若虫或成虫的植株相比，暴露于五龄若虫的植株表现出更多的棉蕾脱落，并且直径3 - 6毫米的棉蕾留存较少。我们的结果表明，五龄若虫对棉花的伤害比三龄若虫或未成熟成虫更大，并且取食伤害的差异与西方盲蝽不同虫龄在植株内的分布情况相对应。
