Influence of Mating Type and Oviposition Period on Mandibular ...

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Fig 1. Mean numbers <strong>of</strong> workers within a length <strong>of</strong> one
worker around m<strong>and</strong>ibular extracts <strong>of</strong> NM <strong>and</strong> II queens
collected after I <strong>and</strong> 2 weeks <strong>of</strong> oviposition during Spring
season <strong>of</strong> 2000. Bars marked by the same letter are not
significantly different.
time for differences in worker's response to NM
<strong>and</strong> II extracts to be observed. Response <strong>of</strong>
workers to solvent controls was also recorded.
Control data were not included in the statistical
tests due to small number <strong>of</strong> replicates.
Workers were used only once for each bioassay
<strong>and</strong> then killed by freezing. On playback, the
videotape was paused every 30 seconds <strong>and</strong> the
number <strong>of</strong> workers that were within one
worker length <strong>of</strong> the rod tip was recorded.
Total number <strong>of</strong> workers were divided by 30 to
obtain the mean number <strong>of</strong> workers found
around the rod for every 30 second.
Pentadecanoic acid (10 Ilg in 5 IIIsolvent)
was added as an internal st<strong>and</strong>ard to each <strong>of</strong>
the 500 III QM extracts, which were then
derivatized with diazomethane to convert fatty
acids to their methyl esters. Two-microliter
aliquots <strong>of</strong> each derivitized extract was injected
with a one III solvent plug in splitless mode
onto a 30-m x 0.25 mm HP-5MS capillary
column (Agilent Technologies) on Agilent
Technologies 6890 gas chromatograph
interfaced to 5973 N mass selective detector
(GC/MS). Analysis conditions were: injector
230 oC, oven 50-240 oC @ 15 OCI min. with a
flow <strong>of</strong> 1.2 ml/min helium <strong>and</strong> the flame
ionization detector (FlD) was set at 250 oc.
Fig 2. Representative Fill chromatogram for m<strong>and</strong>ibular
gl<strong>and</strong> extracts <strong>of</strong> NM <strong>and</strong> II queens collected after
I <strong>and</strong> 2 weeks <strong>of</strong> oviposition in Spring 2000.
*Arrows indicate peaks <strong>of</strong> significant differences: 9.90, 9-
keto-(E)-2-decenoic acid (9-0DA. high levels in NM
queens); 13.60, (Z)-9-octadecenoic acid (OLA, high levels
in II queens). QMP components, methyl p-hydroxybenzoate
(HOB) <strong>and</strong> (9-hydroxy-(E)-2-decenoic acid (9-HDA) are
shown at 8.02 <strong>and</strong> 9.93 m in respectively.
Chemical ionization FID chromatograms were
obtained. Electron ionization (EI) spectra were
also obtained for selected samples from all
treatments. The amount <strong>of</strong> each peak
(compound) was calculated based on the
internal st<strong>and</strong>ard in each sample. To identify
significant peaks <strong>and</strong> the QMP components in
the extracts, relative retention time <strong>and</strong> EI mass
spectra were compared to those <strong>of</strong> pure
compounds accessed via the EI library <strong>and</strong> to
authentic QMP samples obtained from
Pherotech® (Canada).
Minitab statistical s<strong>of</strong>tware (Version 13.1,
State College, Pennsylvania) was used to
compare responses to treatments. one-,two-.,
<strong>and</strong> three-way analysis <strong>of</strong> variance (ANoV A)
tests were used for the statistical analyses <strong>of</strong>
both behavioral bioassays <strong>and</strong> chemical
analysis.
Behavioral Bioassays:
M<strong>and</strong>ibular extracts for NM <strong>and</strong> II queens
1 <strong>and</strong> 2-weeks after oviposition were bioassyed.
Two-way ANoV A revealed that NM extracts
evoked higher responses than II extracts (df-87,