Having learnt that the white spot moth was teetering on the edge of extinction, but was still hanging on in a few areas of South Devon, the Habitat Group decided to see if we could do anything to help it.
It turned out that the white spot was disappearing because there was only one plant that its caterpillars fed on, the nottingham catchfly, which is a really dangerous strategy in a changing world like ours. The nottingham catchfly is a perennial that produces small white flowers on long stems which release a beautiful scent during the night and so attracts many night pollinators, hopefully including the white spot. Each flower only remains open for three nights as a means of preventing self-fertilisation; the flower reveals one whorl of stamens on the first night, the second whorl of stamens on the second night, and the three styles on the third night. The moth lays her eggs on the plant and when the caterpillars are born they feed on the catchfly seeds during the night and then hide around the base of the plant during the day. Unfortunately, with modern farming methods and shrinking areas for wildflowers, the nottingham catchfly is rapidly disappearing and the white spot moth is going with it.
It’s a long shot but in an effort to help any remaining white spots the Habitat Group bought nearly 400 tiny nottingham catchfly plug plants which were distributed among the group last year and planted out in member’s gardens. Some members also sowed catchfly seeds, most of which successfully developed into mature plants.
People’s plants grew well but by the end of last summer strangely only one plant out of that 400 had flowered and gone to seed. This spring, however, all of them took off, grew well and started flowering, releasing their delicious scent as darkness fell. We have no idea which insects visited them but they were certainly pollinated and soon seed pods were forming on everyone’s plants. There was great excitement when members started reporting seeing caterpillars eating the seeds but while we had pretty definite identification of both campion and lychnis moth caterpillars devouring the seeds we didn’t get a positive identification for white spot caterpillars. Bearing in mind, however, that they hide away in the day and only feed at night, it is very likely that we would have missed them even if they had come.
Just as importantly our nottingham catchfly plants gave a feed to a multitude of moths and other nocturnal pollinators as well as benefitting their caterpillars. We’ll keep you posted if we see any white spot moth caterpillars in the coming years.