INFLUENCE OF OLEORESIN CONSTITUENTS FROM PINUS-PONDEROSA AND PINUS-JEFFREYI ON GROWTH OF MYCANGIAL FUNGI FROM DENDROCTONUS-PONDEROSAE AND DENDROCTONUS-JEFFREYI
Td. Paine et Cc. Hanlon, INFLUENCE OF OLEORESIN CONSTITUENTS FROM PINUS-PONDEROSA AND PINUS-JEFFREYI ON GROWTH OF MYCANGIAL FUNGI FROM DENDROCTONUS-PONDEROSAE AND DENDROCTONUS-JEFFREYI, Journal of chemical ecology, 20(10), 1994, pp. 2551-2563
Dendroctonus jeffreyi and D. ponderosae are morphologically similar sy
mpatric species of pine bark beetles over portions of their geographic
ranges; however, D. jeffreyi is monophagous on P. jeffreyi while D. p
onderosae is highly polyphagous. Both species carry a species of mycan
gial fungi that are also very similar in appearance. Growth of the two
mycangial fungi and of the fungus Leptographium terebrantis (associat
ed with the polyphagous and non-tree-killing Dendroctonus valens) in t
he presence of oleoresin constituents of host and nonhost conifers was
tested by placing individual chemicals on agar growth medium and by g
rowing the cultures in saturated atmospheres of the chemicals. The fun
gus associated with D. jeffreyi showed greater tolerance for chemical
constituents placed on the growth medium than the other two fungi, and
growth after three days was enhanced by heptane, the dominant constit
uent of P. jeffreyi oleoresin. Growth of all three species of fungi wa
s reduced by the resin constituents when the chemicals were presented
as saturated atmospheres. The results suggest that the influence of th
e tree on growth of the symbiotic fungi of the bark beetles during the
initial attack process may be different than after colonization by th
e beetles is complete. The difference in the responses of the apparent
ly related species of mycangial fungi may provide some new insight int
o the evolutionary history of these beetle/mycangial fungus/host tree
systems.