Mutualisms are potentially conflict laden interactions, vulnerable to collapse. How mutualisms are stabilized against collapse is a long-standing question in the field. A commonly accepted explanation is that provided by the extension of biological market theory and of host sanctions— one of the partners (symbionts) provides options of commodities or services of varied quality and the other partner (host) chooses from among the symbionts, by selectively allocating resources to more cooperative partners. This explanation brings forth the importance of considering resource allocation, since mutualisms are basically consumer–resource interactions. However, it is one-sided, focussing only on the control on allocation that the host manifests. It ignores any control exercised by the other partner in accessing the resources. These partners have tools for accessing the resources from the host, which can be utilized for controlling the quantity of resources obtained, especially in interactions involving plants, where a source–sink relationship can be established. Sinks are well known manipulators of allocation patterns. Hence a comprehensive study of resource allocation structure and control within mutualisms from the perspective of both hosts and symbionts is a necessary step in understanding stability of mutualistic interactions. Interaction between figs and their pollinator wasps provides us with a good model system to study resource allocation patterns and strategies. The interaction takes place in a closed inflorescence called fig syconium, within which fig seeds and pollinator offspring develop. It provides us with an opportunity to manipulate the occupants of syconium to study the effects on resource allocation. 

In the first part we try to understand patterns of allocation within a fig syconium with reference to biomass and stoichiometry of components of the fig syconium. We show that most of the resources allocated to a syconium are spent on making the syconial wall and the number of pollinator galls has a significant positive effect on the mass of the wall. We also find that pollinator wasps require more resources to develop compared to seeds. When limiting nutrients are involved, asymmetry in nutritional requirements can potentially determine the number of pollinator wasps that a tree can support. Next, we tried to understand, if and how the type and density of occupants influence resource allocation to a syconium. We show that more resources are allocated to syconia that contain both seeds and galls compared to those containing just one of them. This indicates that there might be interaction between the occupants to maximize local resource allocation, showing some level of interdependence between the partners. The size of the syconium increased with increasing density of occupants. However, at low density of occupants, presence of seeds increased the biomass allocation, whereas at high density, presence of galls increased allocation to the fig syconium. Our results thus show that resource allocation in pollination mutualisms is dynamic, and, regulated by both the interacting partners depending on the context of density of occupants.  

We also investigated the role of growth hormones in the differential resource demand exerted by the occupants of the syconium, i.e. seeds and pollinator galls. A preliminary analysis has indicated higher amount of growth hormones released by the pollinator galls. Any study on resource allocation would be incomplete without information on carbon exchange. We determined carbon dioxide exchange of whole syconium to understand if fig syconia can meet some part of their resource demands by photosynthesis. Measurements of respiration rates of syconial occupants has indicated that pollinator galls have higher respiration rates compared to seeds. Overall, pollinator galls are more resource expensive when compared to seeds and can also result in production of larger syconia. Our results highlight the importance of studying resource allocation from the perspective of both the partners.