Discriminative host sanctions in a fig–wasp mutualism

• DOI: 10.1890/13-0749.1
• Publication Date: 2013-11-07T23:04:09Z
• Authors: Rui-Wu Wang; Derek W. Dunn; Bao Fa Sun
• Keywords: Paper wasp; Ficus; Mutualism

In some mutualisms, cooperation in symbionts is promoted by hosts sanctioning "cheats," who obtain benefits but fail to reciprocate. fig-wasp agaonid wasps pollinate the trees (Ficus spp.), are also exploitative using flowers as larval food. Ficus can sanction cheats that aborting un-pollinated figs. However, those figs retained trees, successfully reproduce. When this occurs, wasp broods reduced, suggesting sanctions increase offspring mortality within We investigated mechanisms of abortion and against monoecious racemosa introducing into 1, 3, 5, 7, or 9 female (foundresses) were either all pollen-laden (P+) pollen-free (P-). The rates P- highest (-60%) when single foundresses present. Abortion declined with increased ceased seven more present, irrespective pollination. un-aborted figs, fitness (mean per foundress) foundress number increased, especially Reduced resulted from resulting male-biased sex ratios. Overall estimated both reduced production strengthened increased. a second experiment, we decoupled pollination oviposition one foundress, followed 24 h later ovipositor-excised wasps. Compared P+ single-foundress delayed intermediate fitness, which concurred patterns production. conclude fig reflects pollinator numbers pollen presence. Sanctions initiate soon after discriminate offspring, thus reducing adaptively biasing their suggest costs via these discriminative likely promote stability mutualism.