RNA interference-mediated functional analysis of vitellogenin and vitellogenin receptor in the predatory mite Neoseiulus californicus</p >

Neoseiulus californicus is a key natural predator of spider mites and small arthropod pests. Although vitellogenin (Vg) and vitellogenin receptor (VgR) genes are important regulators of oocyte maturation, egg formation, and embryonic development in spider mites and ticks, their role in phytoseiid mites is less understood. Investigating the reproductive mechanism of predatory mites is crucial for understanding their reproduction and evolution. In this study, three Vg genes and one VgR gene were identified, cloned, and characterized in N. californicus. Vg1, Vg2, Vg3, and VgR mRNAs were 6066, 5728, 4515, and 5331 bp long, encoding proteins comprising 1851, 1849, 1471, and 1722 amino acids, respectively. Temporal expression analysis revealed elevated Vg1, Vg2, and VgR levels in fertilized female adult mites, whereas Vg3 exhibited peak expression during the developmental stage. RNA interference–mediated suppression of Vg1 and Vg2 resulted in 14.66% and 11.59% decreases in fecundity, respectively. Vg1 silencing notably reduced egg hatching rate and female offspring ratio. In contrast, Vg3 and VgR silencing had no significant impact on fecundity and egg hatching rate. These findings provide insights into the regulatory roles of Vg and VgR in predatory mite reproduction, offering a theoretical foundation for understanding their evolution and reproductive strategies.