The evolutionary ecology of fatty-acid variation: implications for consumer adaptation and diversification

Abstract

The nutritional diversity of resources can affect the adaptive evolution of consumer metabolism and consumer diversification. The omega-3 long-chain polyunsaturated fatty acids eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) have a high potential to affect consumer fitness, through their widespread effects on reproduction, growth and survival. However, few studies consider the evolution of fatty acid metabolism within an ecological context. In this review, we first document the extensive diversity in both primary producer and consumer fatty acid distributions amongst major ecosystems, between habitats and amongst species within habitats. We highlight some of the key nutritional contrasts that can shape behavioural and/or metabolic adaptation in consumers, discussing how consumers can evolve in response to the spatial, seasonal and communitylevel variation of resource quality. We propose a hierarchical trait-based approach for studying the evolution of consumers' metabolic networks and review the evolutionary genetic mechanisms underpinning consumer adaptation to EPA and DHA How to cite this article: Twining CW, Bernhardt JR, Derry AM, et al. The evolutionary ecology of fatty-acid variation: Implications for consumer adaptation and diversification.

Cross-Ecosystem Linkages: Transfer of Polyunsaturated Fatty Acids From Streams to Riparian Spiders via Emergent Insects

“…Circles represent sampling sites; squares represent major barriers blocking bed movement. docosahexaenoic acid (DHA, 22:5 ω-3), although DHA levels are normally lower in freshwater than in marine systems (Twining et al, 2020a). Two types of riparian spiders were analyzed at different times of the year: ground-dwelling spiders roaming the riparian area for prey and web-building spiders that are relatively stationary in prey capture.…”

Climate change shifts the timing of nutritional flux from aquatic insects

“…Overall, our analyses reveal a new dimension of phenological mismatch, one that is related to the spatiotemporal variation in nutritional quality of resources and is highly relevant for fitness variation in consumers. 29 Insectivores are largely defined by their foraging strategy rather than their reliance on a single dietary taxon. Thus, seasonal nutritional availability for generalist insectivores in terms of n-3 LCPUFA is largely driven by the phenology of aquatic systems.…”

“…Specifically, algae at the base of aquatic food webs are often rich in n-3 LCPUFA, and these compounds thus are often present at all trophic levels within aquatic food webs. 29 In contrast, terrestrial primary producers typically only contain shorter chain n-3 fatty acids such as a-linolenic acid (ALA). [30][31][32] As a result, terrestrial insects have n-3 LCPUFA contents only 3%-25% those of aquatic insects of the same mass.…”

Copy number variation of a fatty acid desaturase geneFads2associated with ecological divergence in freshwater stickleback populations

“…Nutrient scarcity limits the growth, survival and reproduction of organisms [1,2]. Since habitats vary in nutritional availability, populations in different habitats should experience divergent selection for distinct strategies to optimize acquisition and synthesis of essential nutrients.…”

“…often contain more DHA and EPA than those from freshwater ecosystems, which instead generally contain more ALA [5]. Such spatial variation should generate divergent selection on the consumers, for instance to increase conversion efficiencies of precursors, such as ALA, to DHA in freshwater environments [1,2].…”