干旱区生态环境知识资源中心

The paper deals with the results of the field st;dy of circadian rhythm in Trigonoscelis gigas. This beetle is one of the most promising biological objects for chronobiological studies in spaceships. Active imagines occur on the surface from early spring till late autumn despite the pronounced daily and seasonal contrasts of temperature in the Kara-Kum desert (Turkmenistan). It became possible due to pronounced circadian rhythm of activity. This rhythm is controlled by the mechanism of circadian ’’gates’’: the beetles are active only within morning (6 to 10 AM) and evening (4 to 8 PM) independently from weather and season. We could not stimulate the activity in other hours by the means of artificial lighting or heating in the field experiments performed with beetles placed into enclosures. The temperature of sand surface and the level of illumination may cause some shift of the circadian phases, but only within the relevant time gate. In the natural environment, both gates keep about 12 hrs apart throughout all seasons. Beetles sometimes can skip some gates and stay under sand, if conditions on the surface are unfavorable. We conclude, that T. gigas unlike many other desert animals has a peculiar survival strategy: its activity is related not to the optimal weather conditions, but to rigid time intervals, when the weather over seasons is usually favorable or, at least, never is dangerous.