Ke. Trewhella et al., THE EFFECT OF CONSTITUTIVE RESISTANCE IN LODGEPOLE PINE (PINUS-CONTORTA) AND SCOTS PINE (PINUS-SYLVESTRIS) ON OVIPOSITION BY 3 PINE FEEDINGHERBIVORES, Bulletin of entomological research, 87(1), 1997, pp. 81-88
The acceptance of different provenances or seed origins of lodgepole p
ine Pinus contorta and Scots pine P. sylvestris as suitable ovipositio
n sites was found to vary as a function of both tree age and insect sp
ecies. Experiments on seedling lodgepole pine revealed that the pine s
awfly, Neodiprion sertifer Geoffroy (Hymenoptera: Diprionidae), and th
e larch bud moth, Zeiraphera diniana Guennee (Lepidoptera: Tortricidae
), preferred more southerly provenances of lodgepole pine. The pine be
auty moth, Panolis flammea Denis & Schiffermuller (Lepidoptera: Noctui
dae), however, preferred more northerly provenances. On mature lodoepo
le pine however, P. flammea exhibited a host change, preferring the mo
re southerly provenances. Neodiprion sertifer showed a similar prefere
nce on both seedling and mature provenances. The results of this study
suggest that some provenances of lodgepole pine become more resistant
to attack by P. flammea as they mature, while others become more susc
eptible. This may be related to the feeding strategies of the two inse
cts: P. flammea larvae feed on current year foliage while N. sertiJeu
feeds only on previous year foliage. It is possible that the mechanism
for chemical defence of new shoots changes as the trees mature, and t
o a varying degree in different provenances, while defence of the prev
ious years foliage remains unchanged. Results also indicate that odour
alone as opposed to odour plus visual stimulation may invoke differen
t ovipositional behaviour in N. sertifer.