The effect of host-plant and delayed mating on the fecundity and lifespan of the pine beauty moth, Panolis flammea (Denis & Schiffermüller) (Lepidoptera: Noctuidae): their influence on population dynamics and relevance to pest management

Abstract

Adult females of Panolis flammea (Denis & Schiffermüller) in the laboratory laid more eggs on some provenances of lodgepole pine (Pinus contorta) than on others, even when offered no choice. Their preoviposition period was inversely related to the suitability of the host for larval growth and development. The shorter the preoviposition period the greater the number of eggs that were laid. Delayed mating resulted in reduced fecundity and reduced egg fertility. Female moths lived longest on those hosts on which they oviposited most. Oviposition preferences were correlated with the ratio of the two monoterpenes α- and β-pinene within the host-plants. The effects of provenance, delayed mating and adult mortality were demonstrated through a simulation model; the effect of delayed mating was particularly marked when adult survival was poor. Egg production in the field in Scotland varied from 30 to 123 eggs per female, but this variation could largely be explained by spring temperature. It was concluded that this relationship was due to the influence of temperature on mating and egg laying. The relationship between temperature and egg production forms a basis for predicting damaging levels of Panolis flammea from either pupal or adult numbers. The effects of provenance and delayed mating demonstrate that the frequency of P. flammea outbreaks in the UK may be reduced by the planting of less preferred lodgepole pine provenances and by mating-disruption methods.