There is literature available where different stochastic spatial models of spread are compared that base on different hypothesised dispersal models (e.g. stratified dispersal model vs. diffusion model). The stratified model has the idea that wind and human transportation influences dispersal and invasion and can predict the field situation quite well.

Papers would be e.g.

Gilbert, M., Fielding, N., Evans, H.F. & Grégoire, J.-C. (2003b) Spatial patterns of invading Dendroctonus micans (Coleoptera: Scolytidae) populations in the United Kingdom. Canadian Journal of Forest Research, 33, 712–725.

Gilbert, M., Grégoire, J.-C., Freise, J. F. and Heitland, W. (2004), Long-distance dispersal and human population density allow the prediction of invasive patterns in the horse chestnut leafminer Cameraria ohridella. Journal of Animal Ecology, 73: 459–468. doi: 10.1111/j.0021-8790.2004.00820.x

As far as I know food plants directly at the highways were not involved here but at least in some distance available (in a distance e.g. Cameraria can manage).

The paper:

Hulme, P. E. (2009), Trade, transport and trouble: managing invasive species pathways in an era of globalization. Journal of Applied Ecology, 46: 10–18. doi: 10.1111/j.1365-2664.2008.01600.x

gives a short discussion on human transportation and influences of such corridors and additional references.

Thank You very mach for your suggestions. They are very useful in my studies about the dispersion of Heteroptera in Italy by the principal highways, from Southern, mediterranean coasts, to Northern regions.

Best

Paride