Non-native species

Gripenberg, S., Hamer, N., Brereton, T.M., Roy, D.B. & Lewis, O.T. (2011) A novel parasitoid and a declining butterfly: cause or coincidence?. Ecological Entomology, 36, 271–281.
Brown, P.M.J., Roy, H.E., Rothery, P., Roy, D.B., Ware, R.L., Majerus, M.E.N., Roy, H.E. & Wajnberg, E. (2008) Harmonia axyridis in Great Britain: analysis of the spread and distribution of a non-native coccinellid. From Biological Control to Invasion: the Ladybird Harmonia axyridis as a Model Species pp. 55–67. Springer Netherlands.