Biology Reference
In-Depth Information
(b) Chemical Analysis
The samples were analyzed with a gas chromatograph (GC, Agilent 6890 N) fit-
ted with a HP5 column (30 m 0.32 mm internal diameter x 0.25 µ m film thick-
ness) and a flame ionization detector (FID); hydrogen served as carrier gas. We
injected one micro-liter of each odor sample splitless at 50°C (1 min) followed
by heating to 150°C at a rate of 5°C min -1 , and then to 300°C at a rate of 10°C
per minute before keeping the oven at 300°C for ten minutes. For odor com-
pound identification peak retention times were compared with those of authentic
standard compounds and confirmed by comparison of spectra obtained by gas
chromatography-mass spectrometry (GC-MS). One micro liter aliquots of the
odor samples were injected into a GC (HP G1800A) with a mass selective detec-
tor using the oven and column parameters described above. We discriminated
between active and non-active compounds in the attraction of Handena bicruris
on the basis of electrophysiological recordings and behavioral assays done in an-
other study [20].
(c) Morphology
We counted all newly opened flowers per plant before odor sampling. The next
morning, two flowers per plant were collected and images taken with a digital
camera. We measured floral diameter from these images using the software ImageJ
http://rsb.info.nih.gov/ij and calculated average values.
(d) Moth Rearing
Hadena bicruris (Lepidoptera: Noctuidae) moths were bred in the lab, starting
with adult moths (n = 10, 50% males and 50% females) collected in the sur-
roundings of Zürich, Switzerland, during summer 2005. Wild moths (approx 10
per year) were added to the colony each summer in order to ensure outbreeding.
All insects were reared in controlled conditions under a L16:D8 photoperiod and
temperature of 20 ± 2°C, at 65 - 80% relative humidity (RH). After hatching
of the eggs, larvae were kept in separate plastic containers to avoid cannibalism
and were individually fed with fresh capsules of Silene latifolia until pupation.
The pupae were then sexed and placed in separate rearing cages until emergence.
These emerged adults were used for behavioral experiments before they had any
contact to flowers. Over three successive seasons, a total of 56 flower-naïve moths
(31 females and 25 males) were used for dual choice experiments with flowers of
S. latifolia.
Search WWH ::




Custom Search