TITLE:
Generalist versus Specialist Herbivores on the Invasive Senecio inaequidens and a Native Related Species: What Makes the Difference?
AUTHORS:
Anne-Laure Jacquemart, Valérie Vanparys, Pierre Meerts
KEYWORDS:
Enemy Release; Biotic Resistance; Invasive Plant; Invasive Success; Pyrrolizidine Alkaloids
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.2A,
February
28,
2013
ABSTRACT: We
compared herbivory pressure in the native Jacobaea vulgaris (formely Senecio jacobaea) and the alien invasive S. inaequidens in sites
where they co-occur in Belgium. We predicted that the alien species experiences relaxed herbivory pressure by specialist
herbivores (enemy release hypothesis ERH) whereas it is still attacked by
generalist herbivores. Impacts of two generalist (gastropods and rabbits) and
one specialist (the caterpillar Tyria jacobaeae) herbivores were assessed
with field observations and exclusion experiments. The generalist herbivores
had a higher impact on the biomass and survival of the seedlings of the alien S. inaequidens than on the native J. vulgaris. On the contrary, the specialist Tyria jacobaeae attacked exclusively the
adults of the native species, supporting one of the main predictions of the
ERH. These results are discussed in relation to differences in pyrrolizidine
alkaloid profiles between the two species.