Effects of temperature stress on demographic traits and population projection of Perina nuda (Lepidoptera: Lymantriidae)

Abstract

Perina nuda Fabricius (Lepidoptera: Lymantridae) has emerged as a major pest of Ficus spp. Linné (Rosales: Moraceae), exhibiting widespread distribution across southern China. The present study was designed to assess the impact of temperature on the development and lifetime fecundity of P. nuda. We gathered life-history data of P. nuda under four different temperatures (20 °C, 24 °C, 28 °C, and 32 °C) to analyze through the age-stage, two-sex life table methodology. Subsequently, projected population dynamics were made using these data. Results show that a generation can be completed at experimental temperature; the longest mean longevity (72.012 d) was recorded at 20 °C, while the shortest one was 29.126 d at 32 °C. The highest fecundity (219.5 eggs per female), preadult survival rate (90.6 %), and proportion of females (0.494) were observed at 24 ℃. At 20 °C, the intrinsic rate of increase (r) and the finite rate of increase (λ) were found to be much lower than at other temperatures, with 0.0575 and 1.0591 1/d, respectively. Compared to other temperatures, the net reproductive rate (R₀) at 24 ℃ (108.59) was notably higher than other temperatures. The developmental threshold temperatures and effective accumulated temperatures for egg, larva, pupa, and the entire generation were 10.7 °C (128.02 degree-days), 11.53 °C (362.59 degree-days), 11.86 °C (110.4 degree-days), and 10.85 °C (780.98 degree-days), respectively. A higher population growth rate and a larger population number was observed at 24℃, 28℃ and 32 ℃. Predicted generations varied across Guangdong, ranging from 4.68 in Nanxiong to 6.42 in Leizhou. These findings will help understanding P. nuda biology as influenced by temperature and may be used to predict the distribution and infestation risk under climate warming for this pest of banyan trees.