Ecomorphosis in European Collembola: A review in the context of trait-based ecology

Collembola are a widespread class of arthropods that live mostly in the soil or on its surface. Communities of Collembola have notably been used as bioindicators of several environmental factors such as pollution or land use. Recently, they have also opened perspectives for monitoring the effects of projected climate change on soil biodiversity, in particular through the responses of their traits. Collembola are known to exhibit several morphological variations throughout their lifecycle (other than growth and sexual dimorphism). One of these phenomena, ecomorphosis, has been described as a survival strategy mainly triggered by elevated temperature. This could be of interest in analysing collembolan adaptation to climate change, yet studies on this are -to date -sparse in international literature in English. To begin to address this gap, we conducted a literature review that enabled us to: (i) identify the concepts behind the ecomorphosis strategy, (ii) list the collembolan species known to display ecomorphosis, (iii) summarize its consequences on individuals; and (iv) analyse its theoretical im-plications for community ecology and functional ecology. We then discussed its potential use as a proxy for climate adversity. We thus suggested using the ability of a species to display ecomorphosis as a trait, and in the future test its responses in collembolan communities along climatic gradients. Considering the recent inputs of taking into account intraspecific trait variability in community ecology, we advocate for a better understanding of such eco-physiological strategies in order to improve our hypotheses-based approaches in trait-environment relationships. In a context of rapid global climate change, our findings may provide insights into functional responses to climatic gradients in Collembola, and hopefully contribute to stimulate discussion in other soil fauna biological models.