Effects of a short period exposure of fenitrothion on the reproduction of pregnant females of the guppy, Poecilia reticulata.

Uviovo and Beatty1) reported that zinc decreased brood size and body size of young at birth, but had no effect on the intervals between broods in the guppy. Boyd2) reported that a threshold concentration of organochloric insecticides such as DDT, dieldrin, toxaphen and lindane caused the pregnant females of the mosquitofish to abort. However, little attention has been paid to the stage of pregnancy of the females when exposed to insecticides. Our previous study3) showed that a chronic exposure of sublethal concentrations of fenitrothion and temephos, organophosphorus insecticides inhibited the egg production or induced premature birth in the guppy. The present investigation was a continuation of this study assessing the effects of sublethal concentration of fenitrothion on the reproduction of the guppy. In the present paper, the pregnant females were exposed to the chemical for a rather short period instead of a long period exposure.