Trade-offs in plant defenses against different attackers
are likely central to the ecology and evolution
of induced defenses. Moreover, understanding such
tradeoffs is key to avoiding unwanted side effects if
these pathways are to be manipulated to control pests
in agriculture. In this study, we examined how parasitism
by C. pentagona affects tomato plants’ induced
defenses against a chewing insect, the beet armyworm
(Spodoptera exigua; BAW), by comparing production of
JA and plant volatiles from parasitized and unparasitized
tomato plants. We also determined the growth
rate of BAW caterpillars on parasitized and unparasitized
plants. Finally, we investigated several mechanisms
that might explain the observed impact of C.
pentagona parasitism on tomato herbivore defenses,
including the removal of JA by Cuscuta, negative cross talk between the JA and SA pathways, and the availability
of resources needed for induced defenses.