Morphogenesis of the transport network in jellyfish

While during the evolution organisms enlarged, they had to find ways to overcome the diffusive limit for the exchange of gases and nutrients with the environment. Animals and plants have developed a great variety of strategies to achieve an active transport. Many of these strategies involve spatial network structures: blood vessel networks, pulmonary branching networks, venation in leaves. One of such transport networks is the canal network of the gastrovascular system in jellyfish [1]. It is composed of canals in which seawater flows carrying nutrients and oxygen. As the jellyfish grows, new canals grow from the outer rim of its umbrella towards the stomach. These canals form a quasi two-dimensional network, the dynamics of which are our main focus. We track day-by-day the formation of this transport network in vivo. Due to the ease of observing them and growing genetically identical jellyfish they make a perfect system to study the impact of the physical parameters on the morphogenesis in biological systems. We model the growth of the gastrovascular canal network, studying how the hydrodynamic effects (pressure in the canals [2]) and elasticity of the tissue [1] interplay in governing the growth of the network. In the numerical simulations we show how the canals in the network reconnect, leading to the characteristic hierarchical structure observed in the jellyfish but also in other unstable growth processes.