This Research Topic is part of The Physiological Regulation of Energy Metabolism in Insects series (
Volume I).
Energy is vital for all organisms as it orchestrates indispensable cellular processes and physiological activities. Like for most other animals, carbohydrates, fats and amino acids serve as energy reserves for life activities in insects. Interestingly, insects are also capable of maintaining a balance of energy storage-utilization by adjusting the composition and levels of these energy sources. Energy-producing and storing processes are intricately modulated by a variety of internal factors including genetic composition, lifestyle choices, hormones, metabolites and various external factors, such as environmental fluctuations. Significant contributions to this field have established that energy metabolism plays a central role in growth, development, reproduction, responses to stressors and various other physiological activities in insects.
Sugars are the primary energy sources in most insect tissues due to their high solubility in the hemolymph and their rapid utilization for physiological activities. In this context, the insect fat body is a dynamic tissue that participates in the storage and release of energy to meet energy requirements for physiological processes. Lipids, mainly stored as triglycerides in the fat body are synthesized from dietary carbohydrates, fatty acids or proteins. Unlike carbohydrates and lipids, amino acids are generally used only as supplementary energy sources. Under normal insect physiology, carbohydrates remain the principal energy sources; however, under challenging conditions such as long-term flight, chill stress and starvation, lipids and amino acids also participate in energy metabolism.
Among hormones, insulin and adipokines play key roles in regulating energy metabolism in higher animals. In the case of insects, a series of studies on gene regulation and signaling pathways involved in glycolipid metabolism have been conducted. Similar studies during these years also witnessed great progress in elucidation of the molecular mechanisms of action of hormones involved in physiological regulation of energy metabolism in insects.
This Research Topic on 'The Physiological Regulation of Energy Metabolism in Insects' aims to bring together a collection of research articles and reviews that target different levels of interactions between hormones and energy metabolism, and address the following questions:
1) As other aerobic organisms, the ultimate energy supplier in insects is ATP, which requires the oxidation of glucose via glycolysis and tricarboxylic acid cycle. How do insects use energy efficiently? What are the key genes that play a key role in insect energy utilization?
2) Similar to higher animals, insect organs such as midgut and fat body are involved in energy metabolism. How do insects bring about the regulation of sugar and lipid dynamics?
3) Insects often face various stresses during their life histories, some of which also induce diapause or dormancy. How do insects regulate energy metabolism and maintain homeostasis under such conditions? How are energy metabolites such as carbohydrates, lipids and amino acids regulated by insulin, lipokines and their signaling pathways?
This Research Topic aims to collect current advances on the energy metabolism, including formation, storage and utilization in regulation of insect physiological activities. We encourage submissions from all areas related to identification, characterization and regulation of physiological functions associated with insect energy metabolism. We welcome both full and short reviews and original research articles.