Porcellio ficulneusVerhoeff inhabits xeric Mediterranean grassland habitats. During winter vitellogenesis takes place and mancas are released in April. Under natural conditions some oocytes (about 20%) were lost. Both high temperature (25°C) at long or short photophases affected the reproductive pattern. Thus at 25°C and constant light vitellogenesis was markedly shorter than under field conditions. Oocytes matured sooner, but many were resorbed. The marsupium was formed earlier and contained fewer eggs. In some cases mancas that had developed could not emerge from the marsupium and died inside. In conclusion,P. ficulneusresponds to warmer conditions by breeding earlier and reducing the number of offspring.