Success and Dominance in Ecosystems: The Case of the Social Insects

Book 2 of the Excellence in Ecology series is authored by Professor Edward Osborne Wilson (Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA), the recipient of the ECI Prize 1987 in terrestrial ecology. Ed Wilson has demonstrated excellence in numerous publications centering on the fields of population biology, biogeography, sociobiology, biodiversity, and evolutionary biology. His outstanding achievements and his unique career as research ecologist are highlighted in a laudatio (p. XVII) by Professor Sir Richard Southwood, who chaired the 1987 ECI Jury. The achievements which won Ed Wilson the ECI Prize, as formulated by the jury, have been printed in a document which is reproduced on p. XIV. Ed Wilson's book addresses success and dominance in ecosystems with professional mastery - matured over decades of devoted, critical research. Defining 'success' as evolutionary longevity of a clade (a species and its descendents), and 'dominance' as abundance of a clade controlling the appropriation of biomass and energy and thus affecting coexisting organisms, Wilson exemplifies his subject by referring to eusocial insects, especially termites and ants but also bees and wasps. Eusocial insects are characterized by care of young, overlap of adult generations and division of labor among reproductive and nonreproductive castes. They have achieved an overwhelming dominance and exert a great impact on many other organisms. Their dominance results from competitive superiority based on a sophisticated social organization. Eusocial insects cover a large trophophoric area with near-continuous exploration and defense. Functionally, their colonies are so tightly integrated as to act as superorganisms. Success and dominance of colonial life derive from parallel operations of multiple workers maximizing achievements in the completion of tasks; aggressive, even suicidal behavior; superior protection and exploitation of resources; and enhanced control of a population's microenvironment. Why then have social insects not entirely outcompeted their solitary counterparts? The essence of Wilson's answer to this question: while social insects prevail in terms of biomass in most terrestrial habitats, solitary insects appear to 'fill the cracks' left by social insects, and they breed faster on smaller amounts of resources. Hawaii was not colonized by social insects before the establishment of human societies. This remote archipelago thus provides a chance to study the evolution of the endemic fauna and flora in the absence of social insects. Wilson considers that freedom from social insects - especially ants and termites - may have contributed significantly to some of the characterizing traits of the Hawaiian biota, such as flightlessness, lack of evasive behavior, increased abundance and diversity of beetles and spiders, adaptive predation in some insect groups, and loss of extrafloral nectaries in flowering plants. Ed Wilson's small book is packed with facts, ideas and visions. It floats on a sea of admiration and love for nature. I am sure the book will stimulate further research, as well as interchange among terrestrial, marine and limnetic ecologists, and it will carry the word of a leading scholar devoted to analyzing, comprehending and protecting nature far beyond professional borderlines. [Otto Kinne, Director ECI, from Introduction]