Effect of delayed mating on reproductive biology of the Oriental fruit moth (Lepidoptera : Tortricidae)

The effect of delayed mating on the reproductive biology of females of the Oriental fruit moth, Grapholita molesta (Busck), was studied in the laborat ory. Expected reproduction, defined as r-th day survival rate x percent suc cessful mating x total viable eggs, was reduced by 13, 36, and 74%, respect ively, after a 2-, 5-, and 10-d delay in pairing with a male compared with females that were paired with a male on their day of emergence. Female fert ility (percentage of females laying fertile eggs), fecundity (total number of eggs laid), egg fertility (percentage of eggs developing to black head s tage). and egg hatch (percentage of eggs hatching) were reduced by delays i n mating. The pre-oviposition period of females mated within 24 h of emerge nce was longer than that of females mated 2, 5, or 10 d after emergence. Th e duration of the oviposition period declined with delays in mating. Female longevity increased with delays in mating and was greatest in virgin Femal es. The number of eggs laid per day was similar in Females paired with a ma le 2. 5, and 10 d after their emergence. Commencing 2 d after pairing, fema les paired on their day of emergence exhibited a daily oviposition rate sim ilar to that of Females paired 2-10 d after emergence. These observations s uggest that the successful control of the Oriental fruit moth using sex-phe romone-mediated orientation disruption (mating disruption) is more likely a ccomplished by preventing mating than by delaying mating.