Temperature-sensitve sterile. Maintain at 15-20C. Superficially wild-type at permissive temperatures; contains large bubble-like structures on the inside in all stages (described as large early endosomes), reduced brood size. Sterile and very sick at 25°C with some single escapers that are sterile and sick themselves. Suppressors have been observed after long culturing over several months, periodically check for sterility at 25C.