Effects of delayed mating on reproductive performance of Plodia interpunctella (Hubner) (Lepidoptera : Pyralidae)

Virgin male and female Indianmeal moths, Plodia interpunctella (Hubner), were mated soon after emergence or delayed from mating for 1-5 d, to determine the effect of age at mating on the number of spermatophores transferred by males to females, number of eggs laid (fecundity), egg viability, and adult longevity. When male and female moths were mated without delay, all females mated successfully. On average, each mated female had 2.2 spermatophores and laid 161 eggs. About 99% of the eggs laid were viable. Fecundity and egg viability were significantly and positively correlated with the number of spermatophores/female. For each day that mating of virgin male or female P. interpunctella was delayed, fecundity decreased by about 25 eggs. Egg viability decreased by 22%/d only when females were delayed from mating. Males delayed from mating for 5 d were unable to inseminate females. However, about 23% of females had one spermatophore when females or both males and females were delayed from mating for 5 d. On average, 22-39 non-viable eggs were laid by a female in treatments where male or female moths were delayed from mating for 5 d. Similarly, unmated (virgin) females laid 33 non-viable eggs. These results suggest that methods that can delay and disrupt mating may be effective behavioral strategies for managing this important pest of stored commodities and processed foods. (C) 2002 Elsevier Science Ltd. All rights reserved.