The Effects of Temperature and Diet on Population Dynamics and Reproduction in Ephestia elutella (Hübner) (Lepidoptera: Pyralidae)

Ephestia elutella (Hübner) (Lepidoptera: Pyralidae), an omnivorous pest with a wide range of hosts, is responsible for the damage and loss of many stored commodities. However, the parasitoid wasp Habrobracon hebetor (Say) (Hymenoptera: Braconidae) utilises 5th instars of E. elutella larvae to breed. In order to support the large-scale production of E. elutella for research and parasitoid rearing, we explored the effects of diet (artificial diet and tobacco) on the mortality, developmental duration, adult longevity, fecundity, and population parameters of E. elutella reared at 19°C, 22°C, 25°C, 28°C, and 31°C using age-stage, two-sex life tables. Increasing the temperature from 19°C to 31°C significantly affected the stage-specific mortality, reproductive parameters, and population parameters of E. elutella. Specifically, both developmental duration and adult longevity decreased with increasing temperature. For both diets, pre-adult mortality was lowest at 25°C but was lower overall in populations fed an artificial diet. The developmental duration, adult longevity, and mean generation time (T) were significantly lower in populations fed an artificial diet, whereas the intrinsic rate of increase (r) and finite rate of increase (λ) were significantly lower in populations fed tobacco leaves. Temperature appears to have a significant effect on the development and reproduction of E. elutella, and a combination of 25°C and artificial diet may be the most conducive to large-scale breeding. This study provides a theoretical basis for the mass rearing of E. elutella to support pest control applications in tobacco warehouses.