Factors affecting the dynamics of circadian activity of frit flies Meromyza saltatrix (L.) (Diptera: Chloropidae)

The dynamics of circadian activity in adult frit flies of the Holarctic species Meromyza saltatrix (L.) from Mongolian, Moscow, and Polish populations was studied. Synchronous peaks of activity were revealed with the periodicity multiple of three–four hours, which may depend on the level of light. The direct effect of temperature and humidity on the activity of flies outside the optimal values of these factors was found. It was detected that the peak of adult emergence falls on the beginning of a general increase in the abundance of flies, which indicates constant rejuvenation of the population. The sex ratio is close to 1, but the emergence of males and females is in antiphase. The synchronization of peaks of circadian activity in the populations from different regions confirms the presence of a circadian rhythm of activity. The rhythm synchronizing the reproductive activity of adults was found to be modified by the photoperiod under the optimum conditions of temperature and humidity.