Plant-insect chemical communication in ecological communities: an information theory perspective

Abstract

Cross-species communication, where signals are sent by one species and perceived by others, is one of the most intriguing types of communication that functionally links different species to form complex ecological networks. Yet, global changes and human activities can affect communication by increasing the fluctuations of species composition and phenology, altering signal profiles and intensity, and introducing noises. So far, most studies on cross-species communication have focused on a few specific species isolated from ecological communities. Scaling up investigations of cross-species communication to the community level is currently hampered by a lack of conceptual and practical methodologies. Here, we propose an interdisciplinary framework based on information theory to investigate mechanisms shaping cross-species communication at the community level. We use plants and insects, the cornerstones of most ecosystems, as a showcase; and focus on chemical communication as the key communication channel. We first introduce some basic concepts of information theory, then we illustrate information patterns in plant-insect chemical communication, followed by a further exploration of how to integrate information theory into ecological and evolutionary processes to form testable mechanistic hypotheses. We conclude by highlighting the importance of community-level information as a vehicle to better understand the maintenance of ecological systems, especially when facing rapid global changes.

Floral volatiles evoke partially similar responses in both florivores and pollinators and are correlated with non-volatile reward chemicals

“…FVOCs and pollen chemicals are mostly studied independently, while little is known about potential relationships between FVOCs and other floral chemical traits. Some studies suggest that floral signals are often informative of reward trait quality or composition (Dobson and Bergström, 2000, Hauri et al, 2021, Zu et al, 2022, Essenberg, 2021. Moreover, FVOC production and that of stored toxins could be biosynthetically linked (Dudareva et al, 2013, Pichersky et al, 2006, Twaij and Hasan, 2022.…”

Floral volatiles evoke partially similar responses in both florivores and pollinators and are correlated with non-volatile reward chemicals

“…FVOCs and pollen chemicals are mostly studied independently, and little is known about potential relationships between FVOCs and other floral chemical traits. Some studies suggest that floral signals are often informative of reward trait quality or composition ( Dobson and Bergström, 2000 ; Essenberg, 2021 ; Hauri et al , 2021 ; Zu et al , 2023 ). Moreover, FVOC production and that of stored toxins could be linked biosynthetically ( Pichersky et al , 2006 ; Dudareva et al , 2013 ; Twaij and Hasan, 2022 ).…”

“…Flower chemicals can also serve other functions, such as photoprotection or structural optimization of the flower ( Essenberg, 2021 ). The measurement of chemodiversity has roots in information theory, and chemodiversity can thus be related to the information conveyed by a compound mixture, owing to the innate nature of its entropy ( Shannon and Weaver, 1949 , Allen et al , 2009 ; Zu et al , 2023 ). Certain volatile organic compound (VOC) mixtures may also be informative, acting as unique signals ( Deisig et al , 2006 ).…”

Selection to attract pollinators and to confuse antagonists specializes fig–pollinator chemical communications

“…Producing VOCs with reliable information is thus selectively advantageous for plants, and the selective force to attract pollinators will drive the plants to produce these attractive VOCs (Falara et al, 2013; Lukas et al, 2019). Nevertheless, such reliable information is also easily accessible and utilized by antagonists, and an alternative evolutionary force has been raised, where plant species tend to generate similar VOC profiles for preventing antagonists from locating their preferable hosts (i.e., increasing the complexity and uncertainty of information to identify hosts) (Johnson et al, 2015; Schiestl, 2015; Zu et al, 2020, 2022). Therefore, the fitness (the ability of survival and breeding for living organisms) of plants ought to be simultaneously affected by the selection to attract pollinators and to confuse antagonists.…”