Plants use volatile emissions of neighbors to respond to competitors, herbivores, and pathogens. Plant-plant communication has been demonstrated to depend on emitter-receiver genetic identity in both specialist and generalist plants. We have previously demonstrated that Arabidopsis thaliana shows increased height and fruit number when pre-exposed to volatiles of an intact emitter with a different genotype. However, the consequence of increased allocation of resources to growth for subsequent herbivores has not been explored. We hypothesized that insects feeding on plants primed by emitters of a different genotype would develop more quickly due greater resource availability. We used the diamondback moth (Plutella xylostella), a specialist insect of cruciferous plants, to determine whether emitter identity affects insect development. A. thaliana plants were pre-exposed to emitter plants of the same or different genetic background that were either damaged by P. xylostella larvae or remained intact. After three days, emitter plants were removed and a second instar larvae was applied to each receiver. Larval weight was taken three days after experimental setup. Days to pupation, days to eclosion, adult longevity, and sex were recorded for each individual.
Early developmental parameters (larval weight and days to pupation) were not significantly impacted by plant genotype or herbivory pre-exposure treatments. Priming through herbivore damage pre-exposures did not significantly impact the progression of larvae between any developmental stages or larval weight gain. However, adult P. xylostella lived significantly longer if they fed on plants that had been pre-exposed to a different genotype (p < 0.0094). Additionally, adult P. xylostella weighed 22 percent less when larvae had fed on plants pre-exposed to damaged emitters of a different genotype compared to damaged plants of the same genotype (p = 0.0269). These results show that plant genetic identity can affect not only plant-plant communication, but also indirectly impact the development of an insect herbivore.