Bl. Strom et Ra. Goyer, Effect of silhouette color on trap catches of Dendroctonus frontalis (Coleoptera : Scolytidae), ANN ENT S A, 94(6), 2001, pp. 948-953
With the exception of responses to semiochemicals, host selection behaviors
of . frontalis are largely unstudied. To better understand the host findin
g behavior of D.frontalis, and to identify Potential visual disruptants, we
evaluated the response of D. frontalis to multiple-funnel traps of eight d
ifferent colors, Multiple-funnel traps provide an attractive vertical silho
uette, similar to a host stem, that aids in capturing bark beetles and allo
ws for controlled evaluation of visual cues. Evaluation of mean trap catch
of each color by analysis of variance (ANOVA) produced two separate groups:
white and yellow traps caught significantly fewer D. frontalis than the ot
her six colors tested (black, blue, brown. gray, green, red). Examination o
f spectral reflectance curves showed that the eight colors could be natural
ly placed into two groups, those with high peak reflectance (white and yell
ow) and those with low peak reflectance (black, blue, brown. gray, green, r
ed). When high and low peak reflectance were substituted for color in a sep
arate ANOVA, reflectance group was as good as color at explaining the varia
bility in trap catch (r(2) = 0.88 versus 0.92). Therefore, hue (dominant wa
velength) was unimportant in affecting D.frontalis host finding behavior at
the reflectance levels we tested and, thus, we found no strong evidence th
at differential wavelength sensitivity affected the response of D. frontali
s. These results, show that dark colored silhouettes (those with low reflec
tance values), regardless of hue, are best for capturing D. frontalis, whil
e white or yellow are the best candidate colors for disrupting host finding
.