Effect of altering parent sex ratio on egg laying and subsequent development in plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

Different male and female sex ratios were compared in the parent population of plodia interpunctella (hübner) (lepidoptera: pyralidae) to standardize its laboratory rearing and to use it as fictitious host of beneficial insects. egg laying and percent egg hatching was decreased significantly with the increase in number of males to one female as compared to pairing of one male and one female (control). the highest decrease in fecundity was 20% and in hatching 7% when five males were paired with one female. on the other side,egg laying and hatching was significantly decreased when female number was increased in pairing to one male. in 1:5 (male: female) egg laying per female and hatching percentage was decreased to 61% and 9.8% respectively,over control. there was a significant increase in egg laying and percent egg hatching when males and females were increased in equal ratio in pairing as compared to control. at 150: 150 ratio (male: female) egg laying was 2.5 fold over control,whereas percent hatching was 90% and at par to control. changes in developmental parameters as adult's longevity,larval and pupal periods and fý male to female ratio were non-significant in all treated sex ratios. copyright 2015 zoological society of pakistan.