Several arthropod species, including caterpillars and spiders, commonly construct leaf-based shelters in the form of rolls, tents, and tiers for protection from predators and extreme physical conditions, affording them safety during development and reproduction. By building such shelters, these organisms qualify as ecosystem engineers (Neotrop Entomol 2016; doi.org/10.1007/s13744-015-0348-8), indirectly facilitating arthropod diversity on host plants (Arthropod-Plant Interact 2019; doi.org/10.1007/s11829-018-9661-6).

In the Cerrado Rupestre vegetation of southeastern Brazil (Nat Conserv -Bulgaria 2022; doi.org/10.3897/natureconservation.49.89237), we observed a gall-forming species of nematode that also induces a plant's gall-infested leaves to roll – the first recorded case, to the best of our knowledge (Ecol Entomol 2021; doi.org/10.1111/een.12993). The microscopic (600 μm) nematode Ditylenchus gallaeformans induces galls on the shrub Miconia ligustroides. As the galls develop over time, they cause the undersides of the leaves to curl, forming rolls roughly 20 mm in diameter (top). The interiors of the rolled leaves with attached galls are frequently colonized by many arthropod species, especially spiders, which deposit thick layers of silk to envelop and protect their egg sacs (bottom). As compared to host plants with intact (unmodified) leaves, host plants with gall-induced rolled leaves, which remain on the plants for approximately eight months, are associated with higher arthropod abundance and diversity (Ecol Entomol 2021; doi.org/10.1111/een.12993).

By diverting nutrients to feed the nematode larvae within them, the galls directly damage the host plants. At the same time, however, the galls may indirectly protect host plants from herbivory, given that the spiders that take refuge in these rolled structures repel sap-sucking and chewing insects (Ecol Entomol 2021; doi.org/10.1111/een.12993). Does gall presence have a net positive or negative effect on host plants? In addition, could galls accelerate the decomposition rates of the fallen infected leaves?

包括毛毛虫和蜘蛛在内的几种节肢动物通常以卷、帐篷和层的形式建造基于叶子的庇护所，以保护其免受捕食者和极端物理条件的侵害，从而在发育和繁殖过程中提供安全。通过建造这样的庇护所，这些生物体有资格成为生态系统工程师（Neotrop Entomol 2016；doi.org/10.1007/s13744-015-0348-8），间接促进寄主植物上的节肢动物多样性（Arthropod-Plant Interact 2019；doi.org/10.1007） /s11829-018-9661-6）。

在巴西东南部的 Cerrado Rupestre 植被中（Nat Conserv -Bulgaria 2022；doi.org/10.3897/natureconservation.49.89237），我们观察到一种形成瘿的线虫物种，它也会诱导植物受虫瘿侵染的叶子卷起——这是第一个有记录的记录据我们所知（Ecol Entomol 2021；doi.org/10.1111/een.12993）。微小（600 μm）线虫鸡茎线虫(Ditylenchus gallaeformans)会在灌木Miconia ligustroides上诱发虫瘿。随着时间的推移，虫瘿逐渐形成，它们会导致叶子的底面卷曲，形成直径约 20 毫米的卷（上图）。带有瘿的卷叶内部经常栖息着许多节肢动物，尤其是蜘蛛，它们会沉积厚厚的丝来包裹和保护它们的卵囊（底部）。与具有完整（未修饰）叶子的寄主植物相比，具有虫瘿诱导卷曲叶子的寄主植物在植物上保留约八个月，与更高的节肢动物丰度和多样性相关（Ecol Entomol 2021 ； doi.org/10.1111/ en.12993）。

通过转移营养物质来喂养其中的线虫幼虫，虫瘿直接损害寄主植物。然而，与此同时，考虑到在这些卷状结构中避难的蜘蛛会排斥吸吮汁液和咀嚼昆虫，虫瘿可能会间接保护宿主植物免受草食性侵害（Ecol Entomol 2021；doi.org/10.1111/een.12993） 。虫瘿的存在对寄主植物有正面还是负面影响？此外，虫瘿会加速受感染落叶的分解速度吗？