WASSMER, G.T.; BIXLER, J; FULLER, C.A.; HOBAN-HIGGINS, T.M.; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania; Univ. of California, Davis; Univ. of California, Davis: Observations of the effects of light and gravity on biological rhythms in the desert beetle Cryptoglossa verrucosus

Biological rhythms are daily fluctuations in physiology and behavior that are regulated by an endogenous circadian timing system (CTS). Dysfunction of the CTS is associated with performance decrements, sleep and mental disorders, and jet-lag. Previous experiments with various species have shown that altered gravitational fields through centrifugation or spaceflight can severely impact the CTS. Most studies examining the effect of microgravity are conducted on relatively short flights and reveal only the acute responses to this altered gravitational field. We wish to examine the effects of chronic exposure to microgravity. Our experiments aboard MIR showed that the period of the activity rhythm of beetles chronically exposed to spaceflight was shorter than that of a group exposed to hypergravity, and that the response to light was altered. We propose to extend these experiments by testing the effects of microgravity on the activity rhythm of C. verrucosus during a long-duration stay on the International Space Station. The first phase of these experiments is to verify that this species meets the specific requirements of the mission. To be acceptable to NASA the species must 1) be compatible with existing hardware, 2) exhibit a robust, persistent, and measurable activity rhythm, 3) respond to light in conventional fashion, and 4) survive without food or water for up to 3 months. We will present evidence that this species meets the criteria tested to date. We will present additional data that shows that hypergravity affects the period of the activity rhythm, and preliminary results that suggest the location of the gravity receptor. Research partial supported by NASA grant NAG2-1441.