CF512 Sterility and temperature range!

Hi,

I have recently recieved the mutant strain CF512 [fer-15(b26) II; fem-1 (hc17) IV] which has been described as sterile at 25°C.

I had this strain at room temperature measured to 22.5-23°C and could still see that they laid eggs and got a progeny.

Is this strain just sterile at exact temperature of 25°C?

Is there a temperature range in which this strain is sterile? Can it be still sterile at higher temperatures than 25°C?

thanks a lot

Reza