Modulation of digestive physiology and biochemistry in Mytilus californianus in response to feeding level acclimation and microhabitat.

The intertidal mussel Mytilus californianus is a critical foundation species that is exposed to fluctuations in the environment along tidal- and wave-exposure gradients. We investigated feeding and digestion in mussels under laboratory conditions and across environmental gradients in the field. We assessed whether mussels adopt a rate-maximization (higher ingestion and lower assimilation) or a yield-maximization acquisition (lower ingestion and higher assimilation) strategy under laboratory conditions by measuring feeding physiology and digestive enzyme activities.

More than one way to be an herbivore: convergent evolution of herbivory using different digestive strategies in prickleback fishes (Stichaeidae).

In fishes, the evolution of herbivory has occured within a spectrum of digestive strategies, with two extremes on opposite ends: (i) a rate-maximization strategy characterized by high intake, rapid throughput of food through the gut, and little reliance on microbial digestion or (ii) a yield-maximization strategy characterized by measured intake, slower transit of food through the gut, and more of a reliance on microbial digestion in the hindgut. One of these strategies tends to be favored within a given clade of fishes. Here, we tested the hypothesis that rate or yield digestive strategies can arise in convergently evolved herbivores within a given lineage.