Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.
Department of Ecology, Swedish Univ. of Agricultural Sciences, Uppsala, Sweden.
J Anim Ecol. 2018 May;87(3):801-812. doi: 10.1111/1365-2656.12807. Epub 2018 Mar 13.
Within natural communities, different taxa display different dynamics in time. Why this is the case we do not fully know. This thwarts our ability to predict changes in community structure, which is important for both the conservation of rare species in natural communities and for the prediction of pest outbreaks in agriculture. Species sharing phylogeny, natural enemies and/or life-history traits have been hypothesized to share similar temporal dynamics. We operationalized these concepts into testing whether feeding guild, voltinism, similarity in parasitoid community and/or phylogenetic relatedness explained similarities in temporal dynamics among herbivorous community members. Focusing on two similar datasets from different geographical regions (Finland and Japan), we used asymmetric eigenvector maps as temporal variables to characterize species- and community-level dynamics of specialist insect herbivores on oak (Quercus). We then assessed whether feeding guild, voltinism, similarity in parasitoid community and/or phylogenetic relatedness explained similarities in temporal dynamics among taxa. Species-specific temporal dynamics varied widely, ranging from directional decline or increase to more complex patterns. Phylogeny was a clear predictor of similarity in temporal dynamics at the Finnish site, whereas for the Japanese site, the data were uninformative regarding a phylogenetic imprint. Voltinism, feeding guild and parasitoid overlap explained little variation at either location. Despite the rapid temporal dynamics observed at the level of individual species, these changes did not translate into any consistent temporal changes at the community level in either Finland or Japan. Overall, our findings offer no direct support for the notion that species sharing natural enemies and/or life-history traits would be characterized by similar temporal dynamics, but reveal a strong imprint of phylogenetic relatedness. As this phylogenetic signal cannot be attributed to guild, voltinism or parasitoids, it will likely derive from shared microhabitat, microclimate, anatomy, physiology or behaviour. This has important implications for predicting insect outbreaks and for informing insect conservation. We hope that future studies will assess the generality of our findings across plant-feeding insect communities and beyond, and establish the more precise mechanism(s) underlying the phylogenetic imprint.
在自然群落中，不同的分类群在时间上表现出不同的动态。我们不完全了解为什么会这样，这阻碍了我们预测群落结构变化的能力，而这对于保护自然群落中的稀有物种和预测农业中的害虫爆发都很重要。具有亲缘关系、天敌和/或生活史特征的物种被假设具有相似的时间动态。我们将这些概念付诸实践，以检验取食群、化性、寄生性天敌群落的相似性和/或系统发育关系是否解释了植食性群落成员时间动态的相似性。我们专注于来自两个不同地理区域（芬兰和日本）的两个相似数据集，使用非对称特征向量图作为时间变量来描述栎树上专食性昆虫的物种和群落级动态。然后，我们评估取食群、化性、寄生性天敌群落的相似性和/或系统发育关系是否解释了分类群之间时间动态的相似性。物种特定的时间动态差异很大，从定向下降或增加到更复杂的模式。在芬兰的研究地点，系统发育是时间动态相似性的一个明确预测因子，而对于日本的研究地点，数据对系统发育的影响没有信息。在这两个地点，化性、取食群和寄生性天敌重叠解释的变化都很小。尽管在单个物种水平上观察到了快速的时间动态，但这些变化在芬兰或日本的群落水平上并没有转化为任何一致的时间变化。总的来说，我们的研究结果没有直接支持具有相同天敌和/或生活史特征的物种具有相似时间动态的观点，但揭示了系统发育关系的强烈印记。由于这种系统发育信号不能归因于取食群、化性或寄生性天敌，它可能源于共享的微生境、小气候、解剖结构、生理学或行为。这对预测昆虫爆发和保护昆虫具有重要意义。我们希望未来的研究能够评估我们的研究结果在植物食性昆虫群落及其他群落中的普遍性，并确定系统发育印记背后更精确的机制。
