Reevaluating Spider Nutrition: The Essential Role of Arachidonic Acid in Captivity

Luis A. Roque

Spiders represent one of the most ecologically diverse groups within the class Arachnida, yet their nutritional physiology remains insufficiently elucidated, despite their crucial ecological and experimental significance. In both natural and captive environments, these arthropods occupy key trophic positions that regulate ecosystem dynamics and contribute to the stability of arthropod communities. However, in captivity, whether in laboratory research, zoological institutions, or the collections of private arachnid enthusiasts, the feeding regimens employed are often generalized and fail to consider the biochemical specificity and metabolic demands inherent to spider physiology (Toft, 2013). Surveys of spider keepers and field studies confirm that prey selection is frequently based on convenience rather than nutritional congruence (Survey Output, n.d.), although research shows spiders select prey for optimal nutrient content in the wild (Cuff et al., 2025). This reliance on non-specialized dietary approaches has perpetuated a limited understanding of the metabolic consequences associated with suboptimal nutrition in these taxa.
Emerging evidence from recent zoological and biochemical studies, including advances in lipid metabolism and arachidonic acid (ARA)) research, indicates that current husbandry practices require critical reassessment. Arachidonic acid, a polyunsaturated omega-6 fatty acid, functions as a biochemical precursor to eicosanoids, a group of signaling molecules that mediate essential physiological processes such as reproduction, ecdysis (molting), immune modulation, and neural regulation in invertebrates. These pathways are analogous in function to those observed in vertebrate systems, where eicosanoids exert broad regulatory effects on inflammatory and reproductive processes. Nevertheless, while arachidonic acid biosynthesis and metabolic pathways are well-characterized in vertebrates, the corresponding mechanisms in spiders remain incompletely defined and poorly documented within arachnid nutritional research.

This review aims to synthesize current data regarding the metabolic roles, dietary sources, and physiological functions of arachidonic acid in spiders, situating these findings within the broader context of arachnid nutrition and lipidomics. Arachidonic acid (ARA) and other essential lipids play a vital role in supporting reproductive success, maintaining cuticular integrity, and enhancing metabolic resilience in captive spiders. When these critical fatty acids are deficient, spiders may experience physiological stress, impaired development, or reduced reproductive capacity—conditions frequently observed in laboratory and captive populations. Understanding the mechanisms that regulate (ARA)’s availability and biological function is therefore essential to improving the welfare of captive specimens and the reliability of scientific studies involving them. Drawing upon interdisciplinary findings across biochemistry, ecology, and arachnology, this article proposes a conceptual framework for integrating lipidomic profiling into the nutritional assessment and management of captive spiders. Such an approach encourages the development of evidence-based dietary formulations that align more closely with species-specific metabolic needs and ecological adaptations. By incorporating this lipidomic perspective, the objective is to advance the field toward more refined, species-appropriate feeding strategies that enhance health, longevity, and reproductive outcomes in captive arachnid populations. This integrative model represents a pivotal step toward bridging existing gaps between ecological understanding and practical husbandry, thereby fostering a more scientifically grounded foundation for arachnid care and conservation.