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Research interests

Plant-insect interactions and their roles in plant adaptation and ecosystem functioning

 

Context and issues

Environmental stresses due to climate change, biological invasions and anthropogenic disturbances (pollution, pesticides, etc.) threaten more than ever biodiversity and ecosystems. Plants are sessile organisms that cannot generally escape these stresses quickly. Nevertheless, phenotypic plasticity, which is more frequent in plants, allows them to adapt quickly. In the growing context of changing environmental conditions, species with plastic traits are likely to be favoured and selected. However, the mechanisms at the origin of plant plasticity are still poorly understood and in particular the role that biotic interactions can play in this plasticity via possible mechanisms of induction or inhibition. At the slower scale of evolutionary time, plants adapt to their environment thanks to the mutualistic or even sometimes antagonistic interactions that they establish with other species, notably insects. In response to strong environmental constraints, some plants have thus developed during the course of evolution, singular morphological adaptations at the level of their leaves (e.g. the pitchers of carnivorous plants or bromeliads), of their flowers (e.g. the orchid labellum), or their roots (e.g. the swollen and hollow rhizomes of certain ant-plants). These adaptations are the source of durable and sometimes specific interactions with insects involved respectively in their nutrition (aquatic insects in pitcher plants), their reproduction (pollinating insects) or their defence (ants in myrmecophytes). At the individual level, selection has thus favoured the evolution of a pannel of traits related to shape, odour and color, enabling these plants to effectively attract these mutualistic insects. The study of these traits allows us to understand the fine processes of plant adaptation to their environment, particularly those of plant-insect communication, which are real sources of inspiration for applied research. The study of these biotic interactions also provides a better understanding of the structuring of communities and the functioning of ecosystems. By identifying keystone or sentinel species, they help to understand the threats, through ‘cascade’ effects, to biodiversity and fundamental ecosystem processes.

 

Objectives

The general objective of my research is to understand how plant species adapt to their environment in a context of global change and what is the role of insects in the adaptation of plants to these changes. For a long time, my research has been focused on ant-plants, i.e. myrmecophytes, in tropical forests in Africa and Asia. Currently, they focus on carnivorous plants as they are model plants for understanding phenotypic plasticity, plant-insect fine mechanisms and ecosystem processes.

– At the plant scale, my research aims at (1) assessing the contribution of insect partners to the plant fitness, notably through their protection and nutrition services, (2) characterizing, by a biophysical or biochemical approach, the traits, mutualistic or antagonistic to insects, evolved by plants in response to environmental constraints, (3) characterizing the possible plasticity of these traits and the mechanisms responsible for this plasticity (e.g. leaf shape plasticity in some carnivorous plants).

– At the ecosystem scale, my research on carnivorous pitcher plants, such as Nepenthes from Southeast Asia or Sarracenia from America, extends to all pitcher inhabitants because they form a whole living micro and meso-fauna involved in interactions facilitating plant nutrition and forming model micro-ecosystems, i.e. fully enumerable aquatic microcosms allowing many repetitions and manipulations of species. My research thus aims at (1) understanding the mechanisms of species assemblages, including trophic interactions, facilitation processes, and determinants of diversity, (2) assessing the impact of environmental change on these vulnerable plants and their associated biodiversity, and (3) drawing inspiration from these specialized plants and their ecosystem services to develop traps for the control of pests and/or invasive species (e.g. the Asian Hornet).

This multi-scale approach is at the crossroads of evolutionary biology, sensory ecology, behavioral ecology, community ecology, and applied ecology. The ambition of my research is to contribute, at its level, to a better understanding and mitigation of the current environmental crisis.

 

Keywords : Adaptation, carnivorous plant, myrmecophyte, plant-insect interaction, predation, mutualism, co-evolution, adaptive radiation, leaf morphology, phenotypic plasticity, ‘evo-devo’, insect diversity, aquatic insect community, ecosystem process, viscoelastic fluid, epicuticular wax, odor, color, attraction, invasive species, biomimicry, Asian hornet, honeybees, insect decline.

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