Testing for inhibition of Ips paraconfusus response to aggregation pheromone by odors from logs infested with Dendroctonus brevicomis
Byers, J.A. & Wood, D.L. 1980. Interspecific inhibition of
the response of the bark beetles, Dendroctonus brevicomis
and Ips paraconfusus, to their pheromones in the field.
Journal of Chemical Ecology 6:149-164.

Abstract--
Ponderosa pine logs (Pinus ponderosa) infested with I. paraconfusus
males inhibited the attraction of Dendroctonus brevicomis in the field to
either attractive logs cut from a ponderosa pine tree under attack by
D. brevicomis or to their synthetic pheromones, exo-brevicomin,
frontalin and myrcene. Logs cut from trees under attack by D.brevicomis inhibited the response of I. paraconfusus to logs infested
with male I. paraconfusus. Exo-brevicomin, frontalin and myrcene did
not inhibit their response but verbenone did. Verbenone was found in
male D. brevicomis dissected from attractive logs under attack during
the same time the response of I. paraconfusus was inhibited by these
logs. Trans-verbenol and exo-brevicomin were found in female D.brevicomis while verbenone, trans-verbenol and frontalin were found
in male D. brevicomis in relatively large amounts near the beginning
of the aggregation phase of host colonization. All of these compounds
had decreased at a similar rate 5 days later. This gradual decrease
in exo-brevicomin and frontalin probably caused the reduction in
attraction. The ecological significance of these compounds in
relation to termination of the aggregation phase of D. brevicomis and
reduction of interspecific competition is discussed.
The sex ratios and binomial confidence limits (95%) can be determined
with the quadratic formulas in Spiegel (1961) for binomial confidence
limits for proportions:

p = a/n (the proportion of males)
where a = number of males; n = number of males + females

if 95% confidence limits then z = 1.96

Pu = (p+z^2/(2*n) + z*(SQR((p*(1-p)/n)+(z^2/(4*n^2)))))/(1+z^2/n)
Pl = (p+z^2/(2*n) - z*(SQR((p*(1-p)/n)+(z^2/(4*n^2)))))/(1+z^2/n)

Then:

Sex ratio = number of males/number of females = p/(1 - p)
Upper confidence limit = Pu/(1 - Pu)
Lower confidence limit = Pl/(1 - Pl)

notations are for BASIC (^=to power of, *=multiply, etc.)
Chemical Ecology