Insect herbivores and their parasitoids play a crucial role in terrestrial trophic interactions in tropical forests. These interactions occur across the entire vertical gradient of the forest. This study compares how caterpillar communities, and their parasitism rates, vary across vertical strata and between caterpillar defensive strategies in a semi deciduous tropical forest in Nditam, Cameroon. Within a 0.1 ha plot, all trees with a diameter at breast height (DBH) ≥ 5 cm were felled and systematically searched for caterpillars. We divided the entire vertical gradient of the forest into eight, five-metre strata. All caterpillars were assigned to a stratum based on their collection height, reared, identified, and classified into one of three defensive traits: aposematic, cryptic and shelter-building. Caterpillar species richness and diversity showed a midstory peak, whereas density followed the opposite pattern, decreasing in the midstory and then increasing towards the highest strata. This trend was driven by some highly dense shelter-building caterpillars in the upper canopy. Specialisation indices indicated decreasing levels of caterpillar generality with increasing height, a midstory peak in vulnerability, and increasing connectance towards the upper canopy, although the latter was likely driven by decreasing network size. Both aposematic and shelter-building caterpillars had significantly higher parasitism rates than cryptic caterpillars. Our results highlight nuanced changes in caterpillar communities across forest strata and provide evidence that defences strategies are important indicators of parasitism rates in caterpillars and that both aposematic and shelter-building caterpillars could be considered a “safe haven” for parasitoids.

食草昆虫及其寄生蜂在热带森林的陆地营养相互作用中发挥着至关重要的作用。这些相互作用发生在森林的整个垂直梯度上。这项研究比较了喀麦隆恩迪塔姆半落叶热带森林中毛毛虫群落及其寄生率在垂直地层和毛毛虫防御策略之间的差异。在 0.1 公顷的地块内，砍伐所有胸径 (DBH) ≥ 5 厘米的树木，并系统地寻找毛毛虫。我们将森林的整个垂直梯度分为八个五米的层。所有毛毛虫都根据它们的收集高度被分配到一个层，进行饲养、识别，并分为三种防御特征之一：警戒性、神秘性和庇护所建筑。毛毛虫物种丰富度和多样性呈现出中层峰值，而密度则遵循相反的模式，在中层减少，然后向最高层增加。这一趋势是由树冠上部一些高度密集的建造庇护所的毛毛虫推动的。专业化指数表明，随着高度的增加，毛毛虫的普遍性水平下降，脆弱性达到中层峰值，并且与上层树冠的连接不断增加，尽管后者可能是由网络规模减小所驱动的。警戒毛毛虫和建造庇护所的毛毛虫的寄生率都明显高于隐秘毛毛虫。我们的研究结果强调了整个森林地层毛毛虫群落的细微变化，并提供证据表明防御策略是毛毛虫寄生率的重要指标，并且防御毛毛虫和建造庇护所的毛毛虫都可以被视为寄生蜂的“安全港”。