Plant defence mechanism in honeydew-mediated plant-Hemiptera-ant interactions and ecosystem sustainability: a review

Abstract

The nature and outcome of various population interactions in an ecosystem significantly contribute to its stability. Any shift in frequency and abundance of such interactions including the density of the interacting species, can lead to cascading effects that may destabilize an otherwise balanced self-sustaining ecosystem. Inter-species interaction mediated by hemipteran honeydew is an example of mutualistic association that may provide indirect defence to the host plant. Such associations have been studied extensively due to their ubiquitous nature. Understanding these interactions from ecological and evolutionary perspectives is crucial for unravelling the complexities of mutualistic relationships in the context of communities and ecosystems, that might provide vital clues for sustainable ecosystem management. The plant–Hemiptera–ant association is impacted by several biotic and abiotic factors, varies in time and space, and exhibits context dependency as the outcome varies with environmental conditions where the interaction occurs. A comprehensive review of various dimensions of this complex association has not been attempted so far. Therefore, besides presenting an up-to-date status of research on this complex tripartite interaction among plants, Hemiptera, and ants, the present review examines the ecological costs and benefits for each interacting partner. The key milestones achieved in this emerging field of ecological research during the past five decades have been discussed with a network analysis of authors. The review also identifies a few research gaps, and suggests future research areas to gain deep insight into different dimensions of this association, which in turn might help developing effectivestrategies towards sustainable ecosystem management.