The presence of Δ2-3 somatic transposase to Muller5-B X chromosome carrying five target P-elements causes pupal lethality, even without heat shock P{S-DP} can strongly repress the lethality. P{S-DP} can constitutively repress gonadal dysgenesis through a maternal effect only with or without heat shock. P{S-DP} has no effect on the expression of the Ecol\lacZ gene of P{lacZ}snunspecified or P{lacZ}vasunspecified.