Ts. Sahota et al., INTERACTION BETWEEN SITKA SPRUCE WEEVIL AND ITS HOST, PICEA-SITCHENSIS (BONG) CARR, A NEW MECHANISM FOR RESISTANCE, Canadian Entomologist, 126(4), 1994, pp. 1067-1074
Available information on the interaction between Sitka spruce weevil,
Pissodes strobi (Peck), and its host Sitka spruce, Picea sitchensis (B
ong) Carr., is examined. Based on a theoretical consideration of this
information, a new mechanism is proposed to explain the resistance exh
ibited by some of the genetically distinct individuals of some provena
nces of this species. Experimental evidence is presented to show that
resistant trees can sufficiently affect P. strobi reproduction and pro
geny development and survival to reduce this pest's ability to kill th
e leaders of these trees when challenged with weevils containing alrea
dy mature eggs. Our mechanism also provides an explanation as to how w
eevils are able to avoid attacking and reproducing on resistant trees
in which their progeny would fail.