Rearing carob moth, Ectomyelois ceratoniae (Zell.), on pistachio nuts: biological and statistical approaches

Abstract

The efficiency of pistachio nuts was investigated on the multiplication of Ectomyelois ceratoniae (Zeller) (Lep: Pyralidae) by rearing a cohort of 61 eggs individually at 26 ± 1 ℃, 60 ± 10% RH, and 16:8 h L:D. The age-stage two-sex life table theory and bootstrapping were used to analyze the data. The survival probability from a newly born egg to larva, pupa, and male and female adults was 0.77, 0.52, and 0.26 and 0.24, respectively. The total immature duration of males (45.33 d) was significantly shorter than that of females (49.47 d). The mean female fecundity was 98.08 eggs/fertile female (n = 12) and 78.46 eggs/all females (n = 15), respectively. The life expectancy of a newborn E. ceratoniae was 34.83 d, and the reproductive value was 79.63 at age 49 d of the female. Female moths had slightly longer longevity (7.82 d) compared with males (7.58 d). The population parameters R₀, r, and λ were 19.29 offspring, 0.0548 d⁻¹, and 1.0563 d⁻¹, respectively. When eggs are harvested and the discard age is 62 d, the maximum harvest rate is 0.9481. Therefore, for a daily harvest of 10,000 eggs, the daily recruits of 547 eggs, 421 larvae, 287 pupae, 134 females, and 143 males are required in a stable stage structure rearing system. Each larva damaged and fed upon 2 gr. of raw pistachio to complete its development. Consequently, about 842 gr. pistachio nuts must be provided daily to meet the larval feeding demand, which imposes a cost of about $10 (local retail price) to the rearing system as nutritional provision.