ABSENCE OF THE WHITTEN EFFECT IN CERTAIN INBRED STRAINS OF MICE
Strain differences in the Whitten effect were examined among six inbred strains of mice, NC, KK, DDK, SS, RR and DDY. Two or 3 virgin female mice caged together with a litter brother at 50-80 days of age examined for copulation every morning for a week. The Whitten effect was evident in the NC, KK and SS strains, copulation rates increased greatly on the 3rd night. By contrast, DDK and RR strains showed no such effect, while DDY females exhibited the higher copulation rate on the 1st night. These findings appear to show wide differences in manifestation of the Whitten effect by female mice among different strains.