Effects of delayed mating on the reproductive biology of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae)

The effect of increasing mating delay on the reproductive performance and population growth rates of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), was investigated under laboratory conditions. Virgin females were mated at 1, 3, 5, 7, 14, 21 and 28 days after emergence and reproductive and life table parameters were estimated. The pre-oviposition period (number of days between mating and the onset of oviposition) significantly decreased in females mated within 7 days, whereas females mated at older ages showed equivalent pre-oviposition periods (<4 days). The length of the oviposition period did not vary with increasing age at mating. Female longevity significantly increased in females mated at 21 and 28 days, as a consequence of a longer pre-reproductive period. Fecundity and sex ratio were not affected by the female age at mating, whereas fertility was higher in mealybugs mated at older ages. Additional field observations highlighted that young and old virgin females were equally able to attract males, as both mated on the same day as the field release. Mating delay also affected the life table parameters of P. ficus, as the intrinsic and finite rates of increase did not differ in mealybugs mated within 7 days and significantly decreased in females mated at older ages. The mean generation time and the population doubling time were overall similar in females mated at 1-7 days, and increased significantly in females that experienced longer mating delays. In terms of the mating disruption control of P. ficus, our findings indicate that this method would be effective if mating is delayed >7 days, as shorter delays in mating did not reduce the population growth rates.