Data from: Non-glandular trichomes of Solanum carolinense deter feeding by Manduca sexta caterpillars and cause damage to the gut peritrophic matrix

Plant trichomes constitute a first line of defence against insect herbivores. The pre- and post-ingestive defensive functions of glandular trichomes are well documented and include direct toxicity, adhesion, antinutrition and defence gene induction. By contrast, the defensive functions of non-glandular trichomes are less well characterized, although these structures are thought to serve as physical barriers that impede herbivore feeding and movement. We experimentally varied the density of stellate non-glandular trichomes in several ways to explore their pre- and post-ingestive effects on herbivores. Larvae of Manduca sexta (Sphingidae) initiated feeding faster and gained more weight on Solanum carolinense (Solanaceae) leaves having lower trichome densities (or experimentally removed trichomes) than on leaves having higher trichome densities. Adding trichomes to artificial diet also deterred feeding and adversely affected caterpillar growth relative to controls. Scanning electron and light microscopy revealed that the ingestion of stellate trichomes by M. sexta caterpillars caused extensive damage to the peritrophic membrane, a gut lining that is essential to digestion and pathogen isolation. These findings suggest that, in addition to acting as a physical barrier to deter feeding, trichomes can inhibit caterpillar growth and development via post-ingestive effects.

植物毛状体（plant trichome）是抵御昆虫植食者的第一道防线。腺毛状体（glandular trichome）的摄食前与摄食后防御功能已有大量文献记载，其作用包括直接毒性、黏附、抗营养效应以及防御基因诱导。相较而言，非腺毛状体（non-glandular trichome）的防御功能尚未得到充分阐释，尽管这类结构被认为可作为物理屏障，阻碍植食性昆虫的取食与移动。本研究通过多种方式实验性调控星状非腺毛状体的密度，以探究其对植食性昆虫的摄食前及摄食后效应。实验结果显示，与毛状体密度较高的北美刺龙葵（Solanum carolinense，茄科）叶片相比，取食毛状体密度较低（或经实验移除毛状体）的叶片时，烟草天蛾（Manduca sexta，天蛾科）幼虫的取食启动速度更快，体重增量也更高。与对照组相比，在人工饲料中添加毛状体同样会抑制幼虫取食，并对其生长产生不利影响。扫描电子显微镜与光学显微镜观察表明，烟草天蛾幼虫摄食星状毛状体会对围食膜（peritrophic membrane）造成广泛损伤——围食膜作为肠道内壁结构，对消化过程与病原体隔离均至关重要。本研究结果提示，毛状体除可作为物理屏障抑制取食外，还可通过摄食后效应抑制幼虫的生长与发育。