In crustaceans, neuroendocrine integration, the process in which the nervous and the endocrine systems operate in a coordinated manner to regulate the physiological processes of the organism, is vital to ensure balanced maintenance of homeostasis, both under normal conditions and in stress situations (Christie, 2011; Fanjul-Moles et al., 2006; Hopkins, 2012; Knigge et al., 2021). The complexity of endocrine regulation of development, molting, reproduction, osmoregulation, behavior, morphogenesis, and metabolism in crustaceans is remarkable. Various environmental stimuli can affect the release of many molecules that can act as hormones, neurotransmitters, or both, playing a crucial role in regulating crustaceans´ physiology. Over several decades, extensive research has uncovered these control mechanisms (Chen et al., 2020; Chung et al., 2020; Green et al., 2022 Nagaraju, 2007; Webster et al., 2012). Crustaceans, like other organisms, have a complex physiology due to multiple processes that can overlap and influence each other. These processes can include different life stages from embryo to larva, juvenile to adult, a molting cycle that can occur numerous times during their life cycle, and a reproductive cycle that can alter much of the adult´s physiology (Mykles et al., 2021).

As demonstrated by many recent reviews, crustacean endocrinology already has a solid background (Chen et al., 2020; Knigge et al., 2021 Mykles et al., 2021). However, new information gathered using omics technology (genomics, transcriptomics, and metabolomics) has identified new molecule sequences in crustaceans, including the sequences of new crustacean hormones and of vertebrate-like hormones and enzymes (Bachvaroff et al., 2021; Yuan et al., 2023). Identifying these new molecules has raised many unanswered questions about their evolution and physiological functions. In this review, we aimed to introduce the reader to the field of crustacean endocrinology, providing information on current knowledge on this field, updated with new findings about crustacean hormones focusing on the main neuroendocrine organs and their hormones and the effects of these molecules on the regulation of metabolism, growth, reproduction, and color adaptation. New evidence about vertebrate-type hormones found in crustaceans are also included and discussed. Finally, this review leads to comprehending how crustacean´s endocrine functions can be disrupted by the presence of chemical contaminants in the surrounding environment, which is discussed with more details in the reviews by Rodrigues (2024) and Knigge (2024) in this Special Issue.