Chem. Senses 24: 473-480,
1999
© Oxford University Press 1999
Pheromone-triggered Orientation Flight of Male Moths can be Disrupted by Trifluoromethyl Ketones
Department of Biological Organic Chemistry, Institute of Chemical and Environmental Research of Barcelona (CSIC), Jordi Girona 18–26, E-08034 Barcelona, Spain 1 INRA Unité de Phytopharmacie et Médiateurs Chimiques, Route de St Cyr, F-78026 Versailles Cédex, France
Correspondence to be sent to: A. Guerrero, Department of Biological and Organic Chemistry, Institute of Chemical Environmental Research of Barcelona (CSIC), Jordi Girona 18–26, E-08034 Barcelona, Spain. e-mail:agpqob{at}cid.csic.es
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and methodsResultsDiscussionReferences |
|---|
In a wind tunnel trifluoromethyl ketones (TFMKs) have been found to disrupt the orientation flight of male moths to pheromone sources (virgin females or synthetic pheromone). This is demonstrated by comparison of the flight parameters of the Egyptian armyworm Spodoptera littoralis and the Mediterranean corn borer Sesamia nonagrioides, which had been topically treated with TFMKs, with those calculated for untreated insects. Inhibition occurred in all types of behavior and that of the source contact has been quantified and found to be dose-dependent. The same effect has also been noticed in Mediterranean corn borer males flying to an attraction source consisting of mixtures of (Z)-11-hexadecenyl trifluoromethyl ketone ( 8), a closely related analogue of the major component of the pheromone, and the natural pheromone blend. The most active TFMKs are those closest in structure to the natural pheromone, along with those chemicals which easily hydrate in solution, such as the ß-thiosubstituted derivatives. Along with the previously reported reduction of catches in the field, our results suggest the possible application of these chemicals in future new pest control strategies.
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Insect behavior can be controlled by simple odor compounds or by blends of several components of the sex pheromone. Therefore, many behavior-modifying chemicals can be visualized as potentially useful agents for pest control (Ridgway et al., 1990
). Pheromone-mediated upwind flight orientation to the source constitutes a precise
system to establish how semiochemicals can elicit complex behavioral responses in moths
(Vickers and Baker, 1992; Mafra-Neto and Cardé,
1994; Kaissling, 1997); key factors in governing these
responses are the quality and composition of the odor and the temporal pattern of odor exposure
(Kennedy et al., 1980; Murlis and Jones, 1981; Baker and Kuenen, 1982; Baker et al.,
1985).
Trifluoromethyl ketones (TFMKs) are potent inhibitors of a number of serine esterases and
proteases, such as acetylcholinesterase, chymotrypsin or human liver carboxylesterases (Gelb et al., 1985; Ashour and Hammock, 1987). In insects, TFMKs reversibly inhibit the antennal
esterases responsible for the
catabolism of pheromone molecules in male olfactory tissues (Vogt et al.,
1985; Prestwich and Streinz, 1988; Durán
et al., 1993). Activity of these chemicals arises from the unique features
induced by fluorine, which closely mimics the steric volume of hydrogen at the enzyme receptor
sites. The strong electronegativity of the halogen induces fluorinated ketones to form stable
hydrates in aqueous solutions, forming an adduct, probably a hemiacetal of tetrahedral geometry,
with the active site of the enzyme (Linderman et al., 1988;
Rosell et al., 1996). In the field, some TFMKs have been noted
to reduce catches of males when mixed with the pheromone in several ratios (Parrilla
and Guerrero, 1994; Riba et al., 1994). We present
evidence for the first time that in a wind tunnel TFMKs can disrupt the chemical communication
system of two flying moths, the Egyptian armyworm Spodoptera littoralis (Boisd.) and
the Mediterranean corn borer Sesamia nonagrioides (Lef.), which had been either
topically treated with several doses of these chemicals or attracted to a source containing
mixtures of the pheromone and the fluorinated compounds. The effect was noticed when the
attraction source was either virgin females or synthetic pheromone.
|
Materials and methods |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Insects
The Egyptian armyworm and the Mediterranean corn borer were reared in the laboratory on
slightly modified artificial diets (Poitout et al., 1972; Poitout and Bues, 1974). Pupae were sexed, placed in groups of
20–25 into 20 x 20 cm plastic boxes and maintained in a climatic chamber on a
16:8 light:dark regime at 25 ± 1°C and 65 ± 10% relative humidity until
emergence. Adults were provided with 10% sucrose solution, separated daily by age and kept on
filter paper in plastic containers.
Chemicals
Compounds 1–5 are ß-thiosubstituted TFMKs of molecular
structure RSCH2COCF3 (1, R=C6H13; 2 (OTFP), R=C8H17; 3, R=C10H21; 4, R=C12H25; 5,
R=C15H31), compounds 6–10 and 14
are unsaturated chemicals of
the type RCOCF3 ( 6, R=Z11-C14H27; 7,
R=Z9,E11-C14H25; 8, R=Z11-C16H31;
9, R=Z9-C18H35; 10, R=Z9,Z12-C18H33; 14, R=Z12-C17H33), compound 11 is a bis-TFMK (CF3COC10H20COCF3)
and 12 (OP) is the non-fluorinated derivative C8H17SCH2COCH3. Abbreviations and chemical names (in parenthesis) of the
compounds used are as follows: 1, HTFP (hexylthiotrifluoropropan-2-one); 2,
OTFP (octylthiotrifluoropropan-2-one); 3, DTFP (decylthiotrifluoropropan2-one); 4, DoTFP (dodecylthiotrifluoropropan-2-one); 5, PTFP
(pentadecylthiotrifluoropropan-2-one); 6, Z1114TFMK [(Z)-11-tetradecenyl
trifluoromethyl ketone]; 7, Z9E11-14TFMK [(Z,E)-9,11-tetradecadienyl trifluoromethyl ketone]; 8, Z11-16TFMK [(Z)-11-hexadecenyl trifluoromethyl ketone]; 9, Z9-18TFMK [(Z)-9-octadecenyl
trifluoromethyl ketone]; 10, Z9Z12-18TFMK [(Z,Z)-9,12octadecadienyl trifluoromethyl ketone]; 11, 10BTFMK (10-trifluoroacetyldecyl
trifluoromethyl ketone); 12, OP (octylthiopropan-2-one); 13, Z9E11-14Ac [(Z,E)-9,11-tetradecadienyl acetate]; 14, Z12-17TFMK [(Z)-12-heptadecenyl trifluoromethyl ketone]; 15, Z11-16Ac [(Z)-11-hexadecenyl
acetate]. The major component of the sex pheromone of the Egyptian armyworm (13)
and of the Mediterranean corn borer (15), were obtained from commercial sources. All
fluorinated compounds as well as pheromone components had already been synthesized in our
laboratory (Parrilla et al., 1994; Villuendas et al., 1994) and their purity was >98%.
Behavioral tests
The experiments were performed on insects of scotophases 2 and 3, in S. littoralis
during hours 5 and 6, and in S. nonagrioides between hours 3 and 7. Males were
anaesthetized with CO 2 and carefully handled to apply on the antennae different
doses of the compounds, which had been dissolved in hexane in the required concentration so
that 0.1 µl of the solution contained the desired dose for the test. In preliminary assays,
this amount of solvent did not exert a significant diminution of any behavioral response in moths
relative to control. Males were allowed to recover for 30 min, introduced into the tunnel and
individually tested. Inhibition percentage was determined by the relative decrease in number of
contacts with the source displayed by treated males in comparison to solvent-applied insects. The
attraction source was either 10 µg of 13, the major component of the sex
pheromone of
the Egyptian armyworm (Nesbitt et al., 1973), or 1 µg of
the pheromone blend of the corn borer [a mixture of 15, (Z)-11-hexadecenol, (Z)-11hexadecenal and dodecyl acetate in 77:8:10:5 ratio] (Sans et al.,
1997), or virgin females. Just prior to the experiments, the required amount of
attractant was dissolved in 10 µl of nanograde hexane and applied to dispensers: a brown
female-shaped piece of cardboard for S. nonagrioides or a 5 x 2 cm piece of filter
paper for S. littoralis. The solvent was allowed to evaporate and the dispensers
suspended at 18 cm from the top and 40 cm from the upwind end of the tunnel. When virgin
females were used as attractants, four individuals (10–35 h old) were placed in 6.5
x 4 x 3 cm stainless steel cages of 0.2 x 0.2 cm mesh.
All types of behavior [wing fanning and taking flight (TF), arrival to the middle of the tunnel, close approach to the lure and contact with the source (SC)] were recorded and compared with control and hexane-treated insects. Experiments were conducted in blocks including two or three treatments and control or hexane-treated insects, and statistical analysis was performed within every block. On each day of experimentation, three groups of 8–10 treated males were compared with 10–14 control males until completion of the block.
Assays were conducted in a 180 x 55 x 50 cm glass tunnel, as described
previously (Quero et al., 1995). The active space was visualized
with the aid of a SO 3 smoke dispenser (Drägerwerk, Germany). Illumination
(2–5 lx) was obtained through a dimmed fluorescent red light. A video camera (Pulnix
B/W TM50), linked to a JVC SR306E video recorder and a Panasonic TC-14S1RC monitor, was
placed 135 cm above the tunnel and in a perpendicular position to minimize optical distortion of
the flight. The camera allowed recording of a flight path within a 130 cm long and 45 cm wide
section of the tunnel, and the tracks were traced onto millimetrically scaled acetate sheets and
laid over the monitor screen. Positions were displayed frame-by-frame and the successive moth
positions, separated 0.2 s, marked on the acetate sheet. Locations were arbitrarily converted into X, Y coordinates with regard to the initial male position (X = 0, Y = 0). Plume limits were recorded and traced with a set of points that were adjusted to two
polynomial regression equations (r2 = 0.98), which established the upper (Y > 0) and lower edge (Y < 0) of the plume. Insect positions the
coordinates of
which fell between those delimited by the equations were considered to be inside the plume. The
estimated crosswind dimensions for S. littoralis were 16 and 40 cm wide at 50 and 100
cm, respectively, from the source. For S. nonagrioides the active space was 12 and 31
cm, respectively, at the same distances from the lure. These values result from the optimum wind
speed found for each species: 15 cm/s for S. littoralis and 22 cm/s for S.
nonagrioides. Flight parameters were determined on uninterrupted flights from the platform
to the source and only those males arresting at the source for a minimum period of 5 s were
recorded as SC. For out-of-plume parameters, only males which spent at least 20% of their total
flight time outside the plume boundaries were considered.
For each flight track the following parameters were recorded: flight distance, flight duration,
ground speed, turning frequency, number of intersections with plume, track leg length, track
width, track angle, course angle and drift angle (Marsh et al., 1978) and analyzed for significance (LSD test, P < 0.05).
|
Results |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
In preliminary tests, the pheromone doses cited, i.e. 10 µg of the major component of the pheromone (13), of the Egyptian armyworm and 1 µg of the pheromone blend of the Mediterranean corn borer, had induced the highest number of contacts, fully comparable with those induced by virgin females (unpublished data).
Compounds 2 (OTFP) and 6, which had been found in vitro to be
good inhibitors of antennal esterases of the Egyptian armyworm (Rosell et al., 1996), significantly induced inhibition of SC behavior (77 and 58% for n = 37 and 44 respectively), as did other ß-thioderivatives, such as
compounds 3
and 5 (66 and 44% inhibition for n = 39 and 33 respectively; Figure
1). Compound 9, with a double bond at the same location as in the
pheromone structure, also elicited a remarkable inhibitory effect (49%, n = 33). The best
inhibitor, however, was compound 7, the most closely related analogue of the major
component of the pheromone (13), which exerted an inhibition of 83% (n = 40)
at 500 ng and 63% (n = 32) at 50 ng. These values were only slightly lower than those
obtained with the actual pheromone component 13 (100% inhibition at 500 ng, 79% at
50 ng and 41% at 25 ng/antenna; Figure 1).
|
2 homogeneity
test). The attraction source was 10 µg of (Z,E)-9,11-tetradecadienyl
acetate (13). Number of insects tested is shown in parenthesis.By contrast, compound 12 (OP), the non-fluorinated analogue of 2, did not significantly decrease the number of males contacting the source (55% with regard to 60% of control insects, i.e. only 8% inhibition), which confirms the key role played by fluorine in the inhibitory action of these molecules. This finding was also corroborated when virgin females were used as lures. In this experiment, only 30% of males were able to contact the cage when treated with 100 ng of OTFP (2) vs 73% of solvent-applied males (59% inhibition), while 62% of insects reached the source upon treatment with 500 ng of OP (12) (15% inhibition).
Flight tracks of moths, previously treated with OTFP (2), showed profound
differences compared with those of hexane-applied insects. Males treated with the inhibitor
frequently exhibited erratic progress towards the plume, flying across the wind with high
numbers of intersections with plume boundaries (Figure 2). Males treated
with OTFP took significantly longer to contact the source and flew longer distances than control,
hexane-treated and OP-treated insects (Table 1). Likewise, the number of
intersections with the plume edges was also more than twice the mean value observed for
control, hexane-treated or OP-treated males (22.3 ± 5.6 vs 9.6 ± 1.3, 8.6
± 1.2 and 6.8 ± 0.9, respectively). Ground speed of males flying inside the
plume was not modified by the treatment; however, it was significantly higher in OTFP-treated
males flying outside the plume than in control insects (Table 2).
Interestingly, the turning frequency was practically identical (2.3–2.5 turns/s) in all insects
flying upwind into the plume and also similar in control and OTFP-treated males flying out of the
plume (2.1 turns/s). Track leg length was significantly higher in OTFP-treated males out of the
plume than in any other control or treated males. Also, OTFP significantly increased the mean
track width in flights inside and outside the plume. Likewise, OTFP-treated moths steered
significantly larger track and course angles inside the plume than untreated or OP-applied males,
but they were comparable to those displayed by control insects out of the plume.
|
|
A similar experiment was performed on S. nonagrioides males but, in this case, and on the basis of the previous results, only the steric mimics Z11-16:TFMK (8) and Z12-17:TFMK (14) of the sex pheromone were considered as well as OTFP (2). Previously, application of 500 ng of the pheromone blend to the antenna resulted in a remarkable inhibition of response from the first steps of behavior, i.e. wing fanning and taking flight with only 48% (n = 29) and 10% (n = 29) of males, respectively, responding to the stimulus in comparison to hexane-treated insects (n = 34). This represents an inhibition of these behavioral steps of 51 and 89%, respectively. None of the males treated and flying upwind contacted the source (100% inhibition; Figure 3). Topical application of 1–50 µg of OTFP (2) and 1–10 µg of 14 also resulted in a reduction in the number of males showing the entire sequence of the pheromone-mediated behavior. Both TFMKs evoked a significant inhibition of response at 5 µg dose, the inhibition amounting up to ~53–56% in the number of SC relative to control (Figure 3). Again, the most closely related analogue 8 of the pheromone proved to be the best inhibitor, inducing a significant reduction in the number of males contacting the source at 1 ng/antenna (42% inhibition). The inhibition was dose-dependent (Figure 4).
|
|
The TFMK effect was also tested in a different experiment by recording the behavior of untreated corn borer males flying to an attraction source consisting of mixtures of 2, 8 and 14 and the natural pheromone in 1:1 and 10:1 ratios. In this case, whereas 2 showed no inhibitory effect at any of the doses tested, the presence of 14 in the lure significantly reduced the number of SC at the highest ratio. Thus, only 8 out of 47 (17%) males tested contacted the source, while 24 out of 40 (60%) insects were attracted to the pheromone alone. Compound 8 was again found to be the most active: when mixed with the pheromone in a 1:1 ratio it significantly decreased the number of males displaying all types of behavior. The number of contacts was also reduced by a significant 20.6% (n = 91, P < 0.05,
2 homogeneity test). The effect was also dose-dependent (Figure 5).
|
A number of Mediterranean corn borer flight tracks were also video-recorded after males were treated with 1 ng/ antenna of compound 8 applied topically (Figure 6). As in the Egyptian armyworm, males displayed significantly higher track widths and track leg lengths than untreated males, with frequent inter-turn crosswind and downwind reversals and little progress towards the source. As a result, treated males flew significantly longer than those untreated but, since their ground speed was also comparatively higher, they did not take longer to reach the target (Table 3). In addition to flying faster, moths steered larger course and track angles than control or hexane-treated males, and therefore headed less into the wind. The drift angles were similar in all flying moths. The turning frequency was also relatively constant, as in the Egyptian armyworm. In contrast, treated insects did not lose the active space in higher numbers than untreated males, as shown by the similar number of intersections with the plume boundaries (Figure 6).
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Our results show that for the Egyptian armyworm, in addition to the highly hydrated ß-thiosubstituted TFMKs, whose degree of hydration is an important factor for esterase inhibition (Linderman et al., 1991
), the most potent inhibitors
were those whose structures closely mimic the natural pheromone. It is particularly noteworthy
that the inhibition promoted by compounds 7, the most closely related analogue of the
major component of the pheromone 13, as well as by 6, the analogue containing
only one double bond at position 11, one of the unsaturation locations of the parent pheromone.
Even compound 9, with one unsaturation at C-9 as compound 13, did induce a
significant inhibitory effect in spite of its chain being four carbon atoms longer than the natural
attractant. These results correlate well with the inhibitory activity of antennal esterases of this
insect induced by these TFMKs and ß-thioderivatives in in vitro assays (Rosell et al., 1996). Similar results were obtained for the
Mediterranean corn borer in which, again, the most closely related analogue 8 of the
pheromone proved to be the best inhibitor, the diminution of response being three orders of
magnitude higher than that induced by OTFP (2). The inhibition was remarkable from
the first steps of behavior and the effect was dose-dependent, in a similar manner to that observed
after pre-exposure of Cadra cautella (Mafra-Neto and Baker, 1996) and Epiphyas postvittana (Bartell and Lawrence, 1976) to their respective pheromones.
Most flight parameters of insects treated with the inhibitors were significantly different in
comparison with those of control or solvent-applied males, the exception being the turning
frequency which remained constant before and after treatments. In Lymantria dispar the
turning frequency was also consistent across a 100-fold range of pheromone concentration
(Charlton et al., 1993), which suggests that in S. littoralis and S. nonagrioides the turns are also regulated by an internal self-steered
counterturning program (Kennedy, 1986).
In S. littoralis, all flight parameters displayed by OTFP (2)-applied insects flying inside the plume were fully comparable to those shown by control insects flying outside the plume. This suggests that treated males may not perceive subtle changes in pheromone concentration or that perception of individual pheromone filaments within the plume is being `suppressed' by the treatments, thus inducing insects to behave as if they had lost the plume. This compound therefore induced a large number of casting tracks, with frequent lateral crosswind excursions, in some cases with a slight regression downwind. In S. nonagrioides, TFMK 8 elicits its disruptive effect by strongly modifying the orientation pattern inside the plume, but without inducing males to lose the active space.
It is well known that antennal enzymes are responsible for the catabolism of the sex
pheromone in insects (Kasang, 1971, 1973;
Ferkovich, 1982). Inhibition of these enzymatic systems has been
considered as a potential new approach for pest control (Prestwich, 1986). The effects of TFMKs as inhibitors of esterases (Vogt et al., 1985; Prestwich and Streinz, 1988; Durán et al., 1993; Rosell et al., 1996), on pheromone
catabolism (Quero, 1996), as well as in the electrophysiological
responses to synthetic pheromone components have been reported (Renou et al., 1997). In the same regard and in a preliminary report, pre-exposure of males to
vapors of some TFMKs for 4 h decreased the number of SC (Renou et al.,
1997). The in vivo mode of action of TFMKs cannot be explained by the
antiesterase effect alone, since responses to pheromones with an alcohol or aldehyde function can
also be affected (Renou et al., 1997). Similar results were
obtained by Pophof (Pophof, 1998), who proposed that the inhibition of
the electrophysiological responses promoted by the chemicals might be due to an antagonistic
action at the pheromone binding sites, either at the receptor molecules or at the pheromone
binding protein. In addition, and as shown by us on the processionary moth Thaumetopoea
pityocampa (Feixas et al., 1995), aliphatic TFMKs may be
bound to the pheromone binding proteins and transported through the sensillum lymph, thus
facilitating interaction with the enzymes responsible for pheromone catabolism. The inhibitory
effect of pheromone application is possibly due to overstimulation and adaptation of the receptor
cells, in contrast to the inhibitory effect of the TFMKs which may be due to competitive action of
the inhibitors on the pheromone binding protein and/or the receptor molecules. In any case, the
data presented here show that TFMKs effectively disrupt the orientation flight of the Egyptian
armyworm and the Mediterranean corn borer males, resulting in a significant decrease in the
number of insects reaching the pheromone source (synthetic pheromone or virgin females). These
results, along with the previously reported reduction of male catches in the field promoted by
mixtures of some TFMKs with the pheromone (Parrilla and Guerrero, 1994; Riba et al., 1994), suggest the possible application
of these chemicals in future new pest control strategies.
|
|
Acknowledgments |
|---|
We gratefully acknowledge CICYT (AGF 97-1217-C0201), EC (FAIR CT96-1302), and Comissionat per a Universitats i Recerca (1997SGR 00021) for financial support. We are also indebted to X. Bellés and W.L. Roelofs for useful comments on the manuscript and to SEDQ, SA for providing free samples of S. nonagrioides pheromone.
|
References |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Ashour, M.-B.A. and Hammock, B.D. (1987) Substituted trifluoroketones as potent selective inhibitors of mammalian carboxylesterases.. Biochem. Pharm., 36, 1869–1879.[Web of Science][Medline]
Baker, T., Willis, M.A., Haynes, K.F. and Phelan, P.L. (1985) A pulsed cloud of pheromone elicits upwind flights in male moths.. Physiol. Entomol., 10, 257–265.
Baker, T.C. and Kuenen, L.P.S. (1982) Pheromone source location by flying moths: a supplementary non-anemotactic mechanism.. Science, 216, 424–427.
Bartell, R.J. and Lawrence, L.A. (1976) Reduction in sexual responsiveness of male light brown apple moth following previous brief pheromone exposure is concentration dependent. . J. Aust. Entomol. Soc.,15, 236.
Charlton, R.E., Kanno, H., Collins, R.D. and Cardé, R.T. (1993) Influence of pheromone concentration and ambient temperature on flight of the gypsy moth, Lymantria dispar (L.), in a sustained-flight wind tunnel. Physiol. Entomol., 18, 349–362.
Durán, I., Parrilla, A., Feixas, J. and Guerrero, A. (1993) Inhibition of antennal esterases of the Egyptian armyworm . Spodoptera littoralis by trifluoromethyl ketones.. Bioorg. Med. Chem. Lett., 3, 2593–2598.
Feixas, J., Prestwich, G.D. and Guerrero, A. (1995) Ligand specificity of pheromone-binding proteins of the processionary moth.. Eur. J. Biochem.,234, 521–526.[Web of Science][Medline]
Ferkovich, S.M. (1982) Enzymatic alteration of insect pheromones.. In Norris, D.M. (eds), Perception of Behavioral Chemicals. Elsevier/North Holland, Amsterdam, pp. 165–185.
Gelb, M.H., Svaren, J.P. and Abeles, R.H. (1985) Fluoroketone inhibitors of hydrolytic enzymes. Biochemistry,24, 1813–1817.[Medline]
Kaissling, K.-E. (ed.) (1997) Pheromone-controlled anemotaxis in moths. Birkhäuser Verlag, Basel.
Kasang, G. (1971) Bombykol reception and metabolism on the antennae of the silkworm . Bombyx mori. In Ohloff, G. and Thomas, A.F. (eds), Gustation and Olfaction. Academic Press, New York, pp. 245–250.
Kasang, G. (1973) Physikochemische Vorgänge beim Riechen des Seidenspinners. . Naturwissenschaften,60, 95–101.
Kennedy, J.S. (1986) Some current issues in orientation to odour sources. In Payne, T.L., Birch, M.C. and Kennedy, C.E.J. (eds), Mechanisms in Insect Olfaction. NSF-NATO Symposium on Insect Olfaction. Clarendon Press, Oxford, pp. 11–25.
Kennedy, J.S., Ludlow, A.R. and Sanders, C.J. (1980) Guidance system used in moth sex attraction. Nature,288, 475–477.[Web of Science]
Linderman, R.J., Jamois, E.A. and Roe, R.M. (1991) Correlation of equilibrium hydration constant and inhibitory potency for trifluoromethyl ketone inhibitors of insect juvenile hormone esterase. Rev. Pest. Toxicol.,1, 261–270.
Linderman, R.J., Leazer, J., Roe, R.M., Venkatesh, K., Selinsky, B.S. and London, R.E. (1988) 19F NMR spectral evidence that 3-octylthio,1,1,1-trifluoropropan-2-one, a potent inhibitor of insect juvenile hormone esterase, functions as a transition state analog inhibitor of acetylcholinesterase. Pest. Biochem. Physiol., 31, 187–194.
Mafra-Neto, A. and Baker, T.C. (1996) Elevation of pheromone response threshold in almond moth males pre-exposed to pheromone spray. Physiol. Entomol., 21, 217–222.
Mafra-Neto, A. and Cardé, R.T. (1994) Fine-scale structure of pheromone plumes modulates upwind orientation of flying moths. Nature, 369, 142–144.
Marsh, D., Kennedy, J.S. and Ludlow, A.R. (1978) An analysis of anemotactic zigzagging flight in male moths stimulated by pheromone. Physiol. Entomol., 3, 221–240.
Murlis, J. and Jones, C.D. (1981) Fine scale structure of odor plumes in relation to insect orientation to distant pheromone and other attractant sources. Physiol. Entomol., 6, 71–86.
Nesbitt, B.F., Beevor, P.S., Hall, D.R., Lester, R. and Poppi, R.G. (1973) Sex pheromones of two noctuid moths. Nature New Biol., 244, 208–209.
Parrilla, A. and Guerrero, A. (1994) Trifluoromethyl ketones as inhibitors of the processionary moth sex pheromone. Chem. Senses, 19, 1–10.
Parrilla, A., Villuendas, I. and Guerrero, A. (1994) Synthesis of trifluoromethyl ketones as inhibitors of antennal esterases of insects. Bioorg. Med. Chem., 2, 243–252.[Medline]
Poitout, S. and Bues, R. (1974) Élevage des chenilles de vingt-huit espèces de lepidoptères Noctuidae et deux espèces d'Arctiidae sur milieu artificiel simple. Particularités de l'élevage selon les espèces. Ann. Zool. Ecol. Anim., 6, 431–441.
Poitout, S., Bues, R. and Le Rumeur, C. (1972) Élevage sur milieu artificiel simple de deux noctuelles parasites du coton Earias insulana et. Spodoptera littoralis. Ent. Exp. Appl., 15, 341–350.
Pophof, B. (1998) Inhibitors of sensillar esterase reversibly block the responses of moth pheromone receptor cells. J. Comp. Physiol. A, 183, 153–164.
Prestwich, G.D. (1986) Fluorinated sterols, hormones and pheromones: enzyme-targeted disruptants in insects. Pest. Sci., 37, 430–440.
Prestwich, G.D. and Streinz, L. (1988) Haloacetate analogs of pheromones: effects on catabolism and electrophysiology in Plutella xylostella. J. Chem. Ecol., 14, 1003–1021.
Quero, C. (1996) Estudios sobre el proceso de percepción, inhibición y catabolismo de feromonas sexuales de Lepidópteros. PhD thesis, University of Barcelona.
Quero, C., Camps, F. and Guerrero, A. (1995) Behavior of processionary males (Thaumetopoea pityocampa) induced by sex pheromone and analogs in a wind tunnel. J. Chem. Ecol., 21, 1957–1969.
Renou, M., Lucas, P., Malo, E., Quero, C. and Guerrero, A. (1997) Effects of trifluoromethyl ketones and related compounds on the EAG
and behavioural responses to pheromones in male moths.. Chem. Senses,22, 407–416.
Riba, M., Eizaguirre, M., Sans, A., Quero, C. and Guerrero, A. (1994) Inhibition of pheromone action in. Sesamia nonagrioides by haloacetate analogues. Pest. Sci., 41, 97–103.
Ridgway, R.L., Silverstein, R.M. and Inscoe, M.N. (eds) (1990) Behavior-modifying Chemicals for Insect Management. Marcel Dekker, Inc., New York.
Rosell, G., Herrero, S. and Guerrero, A. (1996) New trifluoromethyl ketones as potent inhibitors of esterases: 19F NMR spectroscopy of transition state analog complexes and structure–activity relationships. Biochem. Biophys. Res. Commun., 226, 287–292.[Web of Science][Medline]
Sans, A., Riba, M., Eizaguirre, M. and Lopez, C. (1997) Electroantennogram, wind tunnel and field responses of male Mediterranean corn borer, Sesamia nonagrioides, to several blends of its sex pheromone components. Ent. Exp. Appl., 82, 121–127.
Vickers, N.J. and Baker, T.C. (1992) Male Heliothis virescens maintain upwind flight in response to experimentally pulsed filaments of their sex pheromone. J. Insect Behav., 5, 669–687.
Villuendas, I., Parrilla, A. and Guerrero, A. (1994) An efficient and expeditious synthesis of functionalized trifluoromethyl ketones through lithium–iodine exchange reaction. Tetrahedron, 50, 12673–12684.
Vogt, R.G., Riddiford, L.M. and Prestwich, G.D. (1985) Kinetic properties of a pheromone-degrading enzyme: the sensillar esterase of
Antheraea polyphemus. Proc. Natl Acad. Sci. USA, 82,8827
–8831.
Accepted May 18, 1999
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  Y. Ishida and W. S. Leal From The Cover: Rapid inactivation of a moth pheromone PNAS, September 27, 2005; 102(39): 14075 - 14079. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||