Data from: Mycorrhizal fungi respond to resource inequality by moving phosphorus from rich to poor patches across networks

The world’s ecosystems are characterized by an unequal distribution of
resources. Trade partnerships between organisms of different species -
mutualisms - can help individuals cope with such resource inequality.
Trade allows individuals to exchange commodities they can provide at low
cost, for resources that are otherwise impossible, or more difficult, to
access. However, as resources become increasingly patchy in time or space,
it is unknown how organisms alter their trading strategies. Here we show
how a symbiotic fungus mediates trade with a host root in response to
different levels of resource inequality across its network. We developed a
quantum-dot tracking technique to quantify phosphorus trading strategies
of arbuscular mycorrhizal fungi simultaneously exposed to rich and poor
resource patches. By following fluorescent nanoparticles of different
colors across fungal networks, we determined where phosphorus was hoarded,
relocated and transferred to plant hosts. We found that increasing
exposure to inequality stimulated trade. Fungi responded to high resource
variation by: (1) increasing the total amount of phosphorus distributed to
host roots; (2) decreasing allocation to storage; (3) differentially
moving resources within the network, from rich to poor patches. Using
single-particle tracking and high-resolution video, we show how dynamic
resource movement may help the fungus capitalize on value differences
across the trade network, physically moving resources to areas of high
demand to gain better returns. Such translocation strategies can help
symbiotic organisms cope with exposure to resource inequality.