in the future and the identification of sex 
attractants to be correspondingly facilitated. 
In spite of these wonderful advances, there 
is no chemical method known today that can 
compete with olfaction in terms of sensitivity 
and, in some cases, in detecting small dif- 
ferences in molecular arthitecture. The silk- 
worm moth (18) [Bombyx mori (L.)], the 
gypsy moth (6), and the American cock- 
roach (19) [Periplaneta americana (L.)] re- 
spond to a millionth of a millionth of a 
microgram or less of their respective sex 
attractants, and this amid the many odors in 
our environment. Our most sensitive analytical 
methods for an organic molecule require about 
a million times this amount. Nevertheless, the 
time is now ripe to tackle these sex attract- 
ant problems, and also to undertake the 
identification of other pheromones (20), which 
are the odorous substances of insect origin 
that control or affect insect behavior and 
development. 
By spreading over a wide area the synthetic 
sex attractant gyplure, we have been trying 
for the past several years to jam chemically 
the female gypsy moth odor signals that 
attract the male (21). With the sex odor 
everywhere, the males should become utterly 
confused in their attempts to find females, 
They may additionally--because of the high 
excitement induced by the lure--become ex- 
hausted in short order, or because they are 
continuously exposed to the lure, they may 
become insensitive to it. If any of these 
reactions occur, the odor-guidance system, 
on which the opposite sexes depend for their 
mating rendezvous, will be impaired, and their 
ability to reproduce in great numbers should 
be depressed. 
An attractive feature of this so-called 'Op- 
eration Confusion" is that no toxicant at all is 
necessary. 
Thus far, "Operation Confusion" has been 
unsuccessful; but we do not believe the idea 
has been properly tested yet. In 1961, we 
found out too late that the gyplure made by 
a commercial firm contained many impurities 
that were inactivating the lure. During the past 
year our group made 30 pounds of gyplure 
for tests to be run this past summer (22), 
but again the large-scale preparation was not 
sufficiently potent and the test had to be 
cancelled. 

38 
These difficulties led to some interesting 
studies. For example, attraction tests of cis 
and trans mixtures of gyplure disclosed that 
when more than 20 percent of the inactive 
trans-gyplure is added to the active cis- 
gyplure, the active material loses its 
activity (23). This is a serious problem, 
because the trans compound is the more 
stable of the two isomers and the shift to 
the trans form is always a likely possibility, 
especially during the preparation of large 
batches of the chemical or after dispersal of 
the chemical in nature, 
However, this problem also brings up a 
most interesting possibility. If trans-gyplure 
were spread over a wide area, it might 
inactivate the natural lure given off by female 
moths. What is more, if this happens, trans- 
gyplure might be as much as five times more 
efficient than the attractive cis analog, be- 
cause the trans compound seems to be able 
to inactivate about five times its weight of 
the active gyplure. 
The attempt to confuse insects with trans- 
gyplure cannot be regarded as a new concept 
in odor chemistry, since it may be con- 
sidered analogous to the masking of an un- 
pleasant odor with another odor. You may 
wish to think of a masking chemical as 
saturating or fatiguing the odor sites so that 
these sites become insensitive to the sex 
attractant. This masking may be caused by a 
Closely related compound and thus brings us 
to the possibility of trying in these confusion 
experiments compounds that are more readily 
available than cis- and trans-gyplure, e.g., 
ricinoleyl alcohol, its derivatives, and similar 
compounds, 
The use of unrelated compounds for mask- 
ing sex attractants is also likely, because 
the masking of odors by unrelated compounds 
is well known. Workers in this field speak of 
masking chemicals by anesthetizing odor re- 
ceptor sites, of preferential solubility of 
chemicals at these sites, and of the possi- 
bility of displacing an odorous chemical with 
a nonodorous one. 
The adaptation of electronics to the measure- 
ment of odor nerve potentials, that is the 
electrophysiological response to odors, offers 
great promise toward unraveling the com- 
plexities of odor phenomena. We have recently 
acquired such a setup at Beltsville, Md. 




