Data from: Highly unsaturated fatty acids in nature: what we know and what we need to learn

The supply and demand of omega-3 highly unsaturated fatty acids (ω-3 HUFA)
in natural ecosystems may lead to resource limitation in a diverse array
of animal taxa. Here, we review why food quality in terms of ω-3 HUFAs is
important, particularly for neural tissue, across a diversity of animal
taxa ranging from invertebrate zooplankton to vertebrates (including
humans). Our review is focused on ω-3 HUFAs rather than other unsaturated
fatty acids because these compounds are especially important
biochemically, but scarce in nature. We discuss the dichotomy between ω-3
HUFA availability between aquatic primary producers, which are often rich
in these compounds, and terrestrial primary producers, which are contain
little to none of them. We describe the use of fatty acids as qualitative
and quantitative tracers for reconstructing animal diets in natural
ecosystems. Next, we discuss both direct and indirect ecological
implications of ω-3 HUFA limitation at the individual, population, food
web, and ecosystem scales, which include: changes in behavior, species
composition, secondary production rates, trophic transfer efficiency, and
cross-ecosystem subsidies. We finish by highlighting future research
priorities including a need for more research on ω-3 HUFAs in terrestrial
systems, more research their importance for higher order consumers, and
more research on the food web and ecosystem-scale effects of ω-3 HUFA
limitation.