The Fate of Radiophosphorus Ingested by House Flies and German Cockroaches1

Abstract
Musca domestica, and Blattella germanica were fed P32-containing medium to study its effect on their fertility. The biological half-life of P32 was 0.8 day for house flies and 9 days for male roaches, whereas in female roaches it did not fall to 50% in the 14-day observation period. House flies fed P32-labeled food continuously for 6 days did not oviposit. After 2 days on normal food a few eggs of low viability were deposited. Flies fed P32 for shorter periods showed inhibited oviposition and fertility and immature ovaries. Larvae reared on p32-medium developed into normal adults. German roaches fed p32 developed oothecae which contained no eggs.