When exposed to continuous darkness at a temperature of 20°C, the mean annual temperature in its biotope, Broscus laevigatus Dej. needs nearly 1 year for its complete development. 7-8 of this are needed for the maturation of the gonads.Continuous darkness combined with a temperature of 30°C delays the maturation of the gonads whereas it is accelerated if this exposure to 30°C is followed by exposure to 20°C.A period of long days with 14/10h-L/D retards the development of the gonads in B. laevigatus. If a period of long days is followed by one of short days with 10/14h-L/D maturation of the gonads is accelerated.Middle European photoperiods have a stronger influence on the development of the gonads than the North African photoperiods.The propagation rhythm of this North African carabid beetl shows marked relations to Middle-European species characterized by autumn propagation and aestivation.