| dc.description.abstract | Comparative repellency of pine, mineral, motor and silicon
oil to house flies, Musca domestica L., was tested in 10-
minute binary choice bioassays, each employing 20 caged, 4-5
day-old flies. Testing the number of flies feeding on 20 ul
of watery honey solutions (HS) mixed with (treatment) or
without (control) 10 ul of one of the oils under
investigation, only pine oil completely suppressed feeding
and remained inhibitory even after 24 hours. Approaching
pine oil-treated HS, 95% of flies were repelled at a
distance > 6 rom from the source, indicating that recognition
of repellent constituents was based on olfaction rather than
contact chemoreception.
Analysis of pine oil volatiles by coupled gas
chromatographic-electroantennographic detection (GC-EAD)
revealed 5 antennally-active compounds, 4 of which were
identified by coupled GC-mass spectrometry as myrcene, paracYmene,
gamma-terpinerie and linalool.
Repellency of these compounds alone or in combination was
demonstrated in a 5-replicate experiment employing one
treatment per cage with 50 flies each. At a 10 ul dose,
significantly lower proportions (P < 0.05) of flies fed on
HS treated with pine oil or one of the four pine oil
constituents. At a 1 ul dose only the linalool-treatment
inhibited feeding. In binary choice experiments both feeding
and oviposition were significantly reduced on linalool(
treated sources. Because fly maggots naturally develop in
and rely on microbe-rich organic sources, gravid females may
percieve and avoid potential oviposition sites that are rich
in antimicrobial compounds such as linalool. | en |
