The effect of sex ratio on the reproductive potential of adult female Tetranychus urticae
Author of the article:SHI Li, ZHANG Ting-Wei, ZHANG Yu-Xia, YUAN Yue
Author's Workplace:Bio-control Engineering Laboratory of Crop Diseases and Pests of Gansu Province, College of Plant Protection, Gansu Agricultural University, Lanzhou 730070, China
Key Words: Tetranychus urticae; sex ratio; fecundity; fitness of offspring
Abstract:
Abstract [Aim] To investigate the effects of paired males on the reproduction potential of adult female Tetranychus urticae. This study aims to determine the key role of sex ratio in population dynamics to establish a scientific foundation for predicting mite population trends. [Methods] A single head feeding technique using the isolated leaf feeding method was employed to investigate the effects of different sex ratios (♀︰♂=3︰0, 3︰1, 3︰2, 3︰3, 3︰4) of T. urticae on female oviposition, oviposition period and adult longevity, as well as offspring hatch rate, eclosion rate and sex ratio. [Results] Reproductive fitness, female adult longevity and offspring fitness were significantly affected by the number of paired males. Mated female T. urticae laid significantly fewer eggs per female compared to unmated females (97.64/female). The oviposition period for mated females gradually decreased with an increasing number of males. Adult longevity was significantly longer in unmated females compared to mated females(P<0.05). Additionally, adult longevity decreased as the number of males increased. There was no significant difference between mated and unmated females in egg hatch rate or nymph eclosion rate (P>0.05), both of which were above 90%. The offspring resulting from parthenogenesis were all male, while offspring from sexual reproduction were predominantly female, with a sex ratio close to 3︰1. [Conclusion] The fecundity of parthenogenic females was higher than amphigenetic females. Different maternal sex ratios had no effect on offspring fitness of T. urticae. T. urticae population has self-regulation ability of sex ratio, the offspring resulting from parthenogenesis were all male. As the number of male mites increased and they paired with females, the rate of sexual reproduction increased, resulting in predominantly female offspring.