On the Biological Diversity of Ant Alkaloids

Ants have outstanding capacity to mediate inter- and intraspecific interactions by producing structurally diverse metabolites from numerous secretory glands. Since Murray Blum's pioneering studies dating from the 1950s, there has been a growing interest in arthropod toxins as natural products. Over a dozen different alkaloid classes have been reported from approximately 40 ant genera in five subfamilies, with peak diversity within the Myrmicinae tribe Solenopsidini. Most ant alkaloids function as venom, but some derive from other glands with alternative functions. They are used in defense (e.g., alarm, repellants) or offense (e.g., toxins) but also serve as antimicrobials and pheromones. We provide an overview of ant alkaloid diversity and function with an evolutionary perspective. We conclude that more directed integrative research is needed. We suggest that comparative phylogenetics will illuminate compound diversification, while molecular approaches will elucidate genetic origins. Biological context, informed by natural history, remains critical not only for research about focal species, but also to guide applied research.