Oxford Ragwort and Friends

The friends are these caterpillars of the Cinnabar Moth (Tyria jacobaeae), They love this ragwort! In fact, they need such a plant to survive. The larvae absorb toxic and bitter tasting alkaloid substances from the ragwort, and assimilate them, becoming unpalatable themselves.

Oxford Ragwort itself has an interesting history. It gets its name from the Oxford Botanic Gardens where plants were first brought in the 1700s. They had been collected from Mount Etna, where they were found growing on the lava fields. By1794 the plant was established on the city walls, having escaped from its original source. With the advent of the railways, Oxford Ragwort, finding the clinker beds of the tracks similar to its original volcanic habitat, spread around the country.

In fact, the plants on which these caterpillars were feeding were right by a local railway. We were crossing a single-track line in the course of a nice afternoon walk, and were just through the gate onto railway property. This is part of the railway that once linked Oxford and Cambridge, but which currently carries passenger traffic only to Bicester. It seems that the government has just given the go-ahead for a scheme that will reopen passenger traffic as far as Bedford as part of the "East-West Link". Just leave the caterpillars alone!