Larval development of Raphidioptera takes one to three (sometimes even
more) years with an obligatory cold stimulus to trigger regular
ontogenesis. However, the quality of the stimulus has been unknown so
far. Therefore mature larvae of Mongoloraphidia sororcula (ASPOCK &
ASPOCK, 1966), Phaeostigma notata (FABRicius, 1781) and Raphidia
mediterranea (ASPOCK, ASPOCK & RAUSCH, 1977) were experimentally
hibernated for different periods of time at 4 C. Thereafter development
was observed until onset of pupation. For all species the cold stimulus
was sufficient for pupation, but rates of successful development were
significantly different in the three species. Results are discussed with
reference to the aspect of specific adaptation to environmental
conditions and of synchronization of development.