library_construction_protocol: Samples were collected in liquid nitrogen until nucleic acid extraction. For all experiments Arabidopsis thaliana (Brassicales: Brassicaceae) ecotype Col-0 was used. The seeds  were sown on a 3:1 mixture of soil (Einheitserde Typ P; Kausek, Mittenwalde, Germany) and vermiculite (Kausek, Mittenwalde, Germany). After three days of stratification at 4 °C in the dark, plants grew in growth chambers under short day conditions (8-h/16-h light/dark cycle, 120 μ mol m−2 sec−1 light intensity, 20 °C, 40% relative humidity). The plants were treated either in the vegetative stage in an age of six weeks or in the reproductive stage in an age of 10 weeks, when the first open flower was observed.  In order to compare the egg-mediated priming response against the P. brassicae larvae of plants in vegetative and in reproductive stage, a full factorial set up was designed with plants in both developmental stages, i.e. plants remained untreated as controls (C), were deposited with P. brassicae eggs (E), were feeding-damaged by P. brassicae larvae (F) or exposed to both stimuli, eggs followed by larval feeding (EF).  To treat the plants with P. brassicae eggs, one butterfly deposited an egg clutch of ca. 40 eggs on one leaf per plant. For egg deposition we selected fully developed, visibly non-senescent leaves. Each plant was treated with a different female individual for egg deposition, thus providing independent samples. All eggs were carefully removed without scratching the plants surface six days after egg deposition with a pair of spring steel tweezers, just before the larvae hatched, that is, when black head capsules of larvae inside the eggs were visible. Feeding-damaged plants were obtained by exposing previously egg-deposited or egg-free plants to ten neonate larvae. The larvae hatched from eggs, which were deposited on non-experimental A. thaliana plants. One day before larval hatching, the eggs were removed from those plants and incubated in petri dishes until larvae hatched and were transferred onto the plants. Each plant was treated with larvae from different butterflies, thus providing independent samples. The larvae were enclosed in a clip cage (2 cm in diameter, 1.7 cm high), which was fixed on the leaf with the former egg clutch. Leaves of untreated control and of egg‐deposited plants without feeding‐damage were covered with empty clip cages.  The citric acid RNA extraction protocol by Oñate Sánchez and Vicente-Carbajosa (2008) was used followed by DNAse treatment with the TURBO DNA Free kit (Ambion).  Illumina TruSeq Stranded Total RNA kit at Macrogen Inc.