Rw. Pemberton et Jh. Lee, THE INFLUENCE OF EXTRAFLORAL NECTARIES ON PARASITISM OF AN INSECT HERBIVORE, American journal of botany, 83(9), 1996, pp. 1187-1194
The extrafloral nectaries of many plants promote ant defense against i
nsect herbivores. We examined the influence of extrafloral nectaries o
n the levels of parasitism of a generalist insect herbivore, the gypsy
moth (Lymantria dispar L.). Larvae and pupae of the moth were collect
ed from trees with and without extrafloral nectaries growing in the sa
me forests in South Korea and reared to evaluate parasitism. More para
sitism occurred on plants with extrafloral nectaries in seven of the n
ine season-long collections at the six sites and in four out of five c
ollecting periods. Parasitism was higher on the four main genera of pl
ants with extrafloral nectaries than on any of five main genera of pla
nts without extrafloral nectaries. There was no difference in parasito
id richness; nine species occurred in each group, eight of which were
the same. There was a positive and almost significant correlation betw
een the abundance of plants with extrafloral nectaries and the parasit
ism of gypsy moth at the sites. Extrafloral nectaries may reduce herbi
vory by inducing more parasitism of the insect herbivores that attack
plants bearing the glands.