Light trap transects – a field method for ascertaining the habitat preferences of night-flying Lepidoptera, using Mythimna turca (Linnaeus 1761) (Lepidoptera: Noctuidae) as an example

The habitat associations of the noctuid moth Double Line Mythimna turca (Linnaeus 1761) were studied in three areas in Britain by setting up light traps equidistant along transects which passed through different habitat types. Counts were made of M. turca at each trap station and the results compared with the habitat present in the vicinity of each trap. The results using chi-square analysis indicate that the preferred habitats for M. turca are woodland and Pteridium aquilinum scrub, especially where the grasses Agrostis capillaris and Holcus mollis occur. The environmental factors affecting moth catches are discussed and chi-squared expectations are adjusted to take account of the different efficiency of light traps in open grassland and woodland situations. The light trap transect method is shown to be useful for moth species where little is known of their ecology and can be used to provide a straightforward insight informing additional targeted autecological studies. The methodology may be less suited to those species which occur at low density, are poorly attracted to light or are known to migrate.