The farming ant Sericomyrmex amabilis nutritionally manages its fungal symbiont and its social parasite. (5th March 2018)

• Record Type: Journal Article
• Authors: Shik, Jonathan Z.; Concilio, Angelo; Kaae, Thomas; Adams, Rachelle M. M.
• Is Part Of: Ecological entomology. Volume 43:Number 4(2018)
• Page Start: 440
• Page End: 446
• Publication Date: 2018-03-05
• Subjects: Ecological stoichiometry -- geometric framework -- nutritional ecology -- social parasite -- symbiosis; Insects -- Ecology -- Periodicals; Entomology -- Periodicals; 595.7
• DOI: 10.1111/een.12512
• Languages: English
• ISSNs: 0307-6946

Abstract

Abstract : 1. When parasites exploit mutualisms involving food exchange, they can destabilise the partnership with costs to interacting partners. For instance, the ant Sericomyrmex amabilis farms fungal symbionts to produce food, but, in so doing, attracts parasitic Megalomyrmex symmetochus guest ants that infiltrate fungus‐farming ant societies and live with their hosts their entire lives. 2. The present study examined whether host foraging in parasitised colonies shifts towards nutritional requirements of the parasitic guest ants as inferred from the parasite's elemental content (%C, %N, and C:N). 3. Laboratory feeding experiments with nutritionally defined diets indicated that S. amabilis ants harvest protein‐biased substrate, and more total substrate when hosting M. symmetochus relative to when provisioning their fungus gardens and nestmates. 4. Field surveys further showed that parasitised colonies incur reductions in fungus garden nutritional quality and quantity, brood mass, and host worker body condition. And yet these costs appear manageable across growing seasons, as parasitised fungal cultivars appear to provide sufficient nutrition for stable populations of host ants. 5. The approach developed here shows how behavioural strategies for nutrient regulation can extend beyond the needs of the individual to entire fungus‐farming systems, and implies that S. amabilis dynamically adjusts collective foraging strategies when parasitised to enhance long‐term symbiotic stability. Abstract : This study explored how fungus‐farming Sericomyrmex amabilis ants nutritionally manage the hosting of multiple symbiotic partners (fungal cultivars and socially parasitic Megalomyrmex guest ants) with varying nutritional requirements. Laboratory feeding experiments with nutritionally defined diets indicated that host ants harvest more protein, and more total substrate when hosting social parasite ants than when provisioning their fungus gardens. Field surveys showed that parasitised colonies incur reductions in fungus garden nutritional quality and quantity, brood mass, and host worker body condition and yet remain stable across growing seasons.