Demographic Characteristics of Novius penicillioides (Coleoptera, Coccinellidae) in Relation to Icerya jacobsoni (Hemiptera, Monophlebidae) Reared on Different Host Plants

The cottony cushion scale, Icerya jacobsoni (Hemiptera: Monophlebidae), is a highly polyphagous pest inflicting significant damage to multiple crops and ornamental plants across the globe. The study investigates the impact of four distinct host plants (Macaranga tanarius L., Magnolia denudata L., Ficus microcarpa L., and Psidium guajava L.) on the biological traits and life table metrics of I. jacobsoni and Novius penicillioides Tao & Wang (Coleoptera: Coccinellidae) feeding on I. jacobsoni, under controlled laboratory conditions. The results showed that host plants significantly influenced the growth period, survival rate, fecundity, and life table parameters of all I. jacobsoni stages. I. jacobsoni performed best on M. tanarius, exhibiting the shortest growth period, highest fecundity, and highest intrinsic rate of increase. In contrast, F. microcarpa was the most unsuitable host, resulting in delayed growth, lower survival, and reduced fecundity. Furthermore, this host-mediated effect propagated up the food chain, significantly impacting the performance of the natural enemy, N. penicillioides. Ladybirds feeding on I. jacobsoni (reared on M. tanarius) developed faster, exhibited higher fecundity, longer longevity, and greater population growth potential. Conversely, those feeding on prey grown on F. microcarpa had suppressed growth and life history parameters. These findings highlight the critical role of host plants in I. jacobsoni population dynamics and N. penicillioides biocontrol efficacy, providing insights for integrated pest management strategies.