Observations on the Ovipositing Strategy of Gortyna Borelii Pierret, 1837 (lepidoptera, Noctuidae) in a British Population

The main British population of Gortyna borelii occurs on the north Essex coast, on sites very close to sea level. During 1999, 2000 and 2001, ovipositing strategies of G. borelii were studied providing details of egg laying behaviour, preferred oviposition host plants, height of ova deposition and distance of the oviposition site from the nearest larval food plant (Peucedanum officinale). Six oviposition host plants were identified, five of which were grass species: 75% of the observations were on Elytrigia atherica and Elytrigia repens with the female depositing eggs between the grass inflorescence and the outer leaf sheath. Sites with the highest incidence of oviposting females were dominated by long, coarse grasses (>75% of ground cover mainly Elytrigia spp.) and a sparse distribution (<25% of ground cover) of Peucedanum officinale. Surface morphology, size and shape of ova were described using scanning electron microscopy. The results of the study are important in the conservation of the species in the United Kingdom.