The influence of Pieris brassicae feeding on kale was monitored, by evaluating its effect on the volatiles
released by the plant through time. This is the first study applying headspace solid-phase microextraction
(HS-SPME) and gas chromatography/ion trap-mass spectrometry to an isolated insect, as most studies
analyse the insect–plant system as a whole, being unable to evaluate the contribution of the insect itself.
Substantial differences were noticed between the volatiles composition of kale before and after the
insect’s attack. More than 60 compounds were found, including terpenes, lipoxygenase pathway by-products,
ketones, norisoprenoids, etc. After insect attack, l-camphor, sabinene and a-thujene were found and
limonene and eucalyptol suffered a noticeable increase. A considerable rise in (Z)-3-hexenyl acetate was
also observed. In vivo accumulation of limonene and camphor by the insect was detected. The findings
contribute to the knowledge of the ecological interactions between the two species.
