Plant-mediated facilitation between a leaf-feeding and a phloem-feeding insect in a brassicaceous plant: from insect performance to gene transcription

Not really a moth, but a butterfly. That distinction does not make sense anyway.

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2011.01902.x/full

Similar to Roy's point, but with a moth: Aphid feeding can suppress plant defenses induced by caterpillar feeding:

Schwartzberg, E.G., Böröczky, K. and Tumlinson, J.H. 2011. Pea aphids, Acyrthosiphon pisum, suppress induced plant volatiles in broad bean, Vicia faba. Journal of chemical ecology, 37: 1055-1062.

Thank you Roy and Justin, I already know those papers, are very good works!

A recent American Entomologist article (2015 vol 61, no 3) is about mostly butterflies feeding on honeydew , extrafloral nectaries and galls.  That may be of interest to you.

Thanks Walter!