(Introduction)Studying invertebrate physiology is an exciting domain, because it provides on one hand insight into general principles of animal physiology, utilizing models with different degrees of complexity and on the other hand it allows studying evolutionary adaptations to a multitude of different lifestyles. Environmental constraints and basic construction principles have led to an amazing variation of physiological solutions to breathe, to ingest and digest food, to reproduce and to communicate and all this on the basis of a wide range of anatomical construction principles. Therefore, a comparative approach to invertebrate physiology is extremely rich and can only be encouraged. The goal of Frontiers in Invertebrate Physiology is to cover a wide range of approaches from the molecular to the cellular, organismic, and even the population level. Studies on model and non-model organisms and on all aspects of physiology will be published, to provide a forum for exchange of recent advances in the field.Invertebrates represent 95% of all living animal species. They have colonized all habitats on earth, including Polar regions, deserts, and seas. Their external skeleton (at least for some of the most prominent invertebrate groups) and their segmented central nervous system make them unique models to study developmental physiology (e.g., molting processes) and the gradual architectural evolution of their central nervous system, and the resulting neural and sensory physiology. Moreover, many invertebrate species are organized in very sophisticated societies, thus offering exciting challenges to study the physiology of intra- and inter-specific interactions and their adaptation to environmental constraints (Woodard et al., 2011).