Humidity sensation, cockroaches, worms and humans: are common sensory mechanisms for hygrosensation shared across species?

Although the ability to detect humidity (i.e. hygrosensation) represents an important sensory attribute in many animal species (including humans), the neurophysiological and molecular bases of such sensory ability remain largely unknown in many animals. Recently, Russell and colleagues (Russell J, Vidal-Gadea AG, Makay A, Lanam C, Pierce-Shimomura JT. Proc Natl Acad Sci U S A 111: 8269-8274, 2014) provided for the first time neuromolecular evidence for the sensory integration of thermal and mechanical sensory cues which underpin the hygrosensation strategy of an animal (i.e. the free-living roundworm Caenorhabditis elegans) which lacks specific sensory organs for humidity detection (i.e. hygroreceptors). Due to the remarkable similarities in the hygrosensation transduction mechanisms used by hygroreceptor-provided (e.g. insects) and hygroreceptor-lacking species (e.g. roundworms and humans), Russell and colleagues' findings highlight potentially universal mechanisms for humidity detection which could be shared across a wide range of species, including humans.