CHEMORECEPTION AND THE BEHAVIOR OF INSECTS
177
ing power. The effectiveness of isolated antennae is greatly reduced after
three days. The attractive material is still effective after thirty minutes
at 70 °C and washing for two days in cold water. Two hours in hot
water or five minutes in organic solvents reduces or abolishes the effectiveness. It is clear that there is on the bodies of B. germanica some material which is soluble in organic solvents, a material which is perceived
by the antennae of males and stimulates them to court. The female
responds to courting by feeding on the glandular products of the male.
Apparently the stimulus to copulation by the male is the mechanical
stimulus of the feeding female. This stimulus can be imitated artificially
with success.
Perception of the female substance by male cockroaches can be
mediated through the antennae; however, males lacking antennae and
palpi are still able to discriminate female from male antennae provided
these are applied to the mouthparts. It is known from the experiments
of Frings and Frings (1949) that some contact chemoreceptors, sensitive
to sugars at least, are present on the tip of the hypopharynx and lígula.
On the other hand, no contact receptors were found on the antennae
(as judged by the sugar test). Clearly there are receptors on the antennae which are stimulated by the female substance, but only upon contact. Surely, this is contact chemoreception. There seems little reason
for terming it tacto-olfaction or for distinguishing between this and the
contact chemoreceptors subserving taste. The use of a contact chemical
sense for recognition is not at all uncommon among insects (see Roth
and Willis, 1952a). Furthermore, it has been known since the experiments of Kunze (1933) and von Frisch (1934) that the antennae of Hymenoptera possess, in addition to receptors mediating olfaction, also
receptors sensitive to sugar. Also, the tapping response of Drosophila
just described indicates that there are contact receptors on the tarsi by
which sex can be discriminated, as well as receptors sensitive to sugars.
Obviously contact chemoreception, or taste, is concerned with sexual
behavior as well as with feeding.
As far as is known, olfaction serves a more important role than taste
in the courtship behavior of the American cockroach, Peripfoneta
americana. Females of this species emanate an odor which is highly stimulating to males. Upon perceiving the odor males become greatly excited
and may even attempt to copulate with a surface which has become
contaminated with the odor. The substance is truly an attractant which
acts in the gas phase and enables the male to locate the female. The
odor is perceived through receptors located on the antennae; antennaless males are quite incapable of being excited. The cockroach attractant
is the first one which has been studied quantitatively in terms of the
177
ing power. The effectiveness of isolated antennae is greatly reduced after
three days. The attractive material is still effective after thirty minutes
at 70 °C and washing for two days in cold water. Two hours in hot
water or five minutes in organic solvents reduces or abolishes the effectiveness. It is clear that there is on the bodies of B. germanica some material which is soluble in organic solvents, a material which is perceived
by the antennae of males and stimulates them to court. The female
responds to courting by feeding on the glandular products of the male.
Apparently the stimulus to copulation by the male is the mechanical
stimulus of the feeding female. This stimulus can be imitated artificially
with success.
Perception of the female substance by male cockroaches can be
mediated through the antennae; however, males lacking antennae and
palpi are still able to discriminate female from male antennae provided
these are applied to the mouthparts. It is known from the experiments
of Frings and Frings (1949) that some contact chemoreceptors, sensitive
to sugars at least, are present on the tip of the hypopharynx and lígula.
On the other hand, no contact receptors were found on the antennae
(as judged by the sugar test). Clearly there are receptors on the antennae which are stimulated by the female substance, but only upon contact. Surely, this is contact chemoreception. There seems little reason
for terming it tacto-olfaction or for distinguishing between this and the
contact chemoreceptors subserving taste. The use of a contact chemical
sense for recognition is not at all uncommon among insects (see Roth
and Willis, 1952a). Furthermore, it has been known since the experiments of Kunze (1933) and von Frisch (1934) that the antennae of Hymenoptera possess, in addition to receptors mediating olfaction, also
receptors sensitive to sugar. Also, the tapping response of Drosophila
just described indicates that there are contact receptors on the tarsi by
which sex can be discriminated, as well as receptors sensitive to sugars.
Obviously contact chemoreception, or taste, is concerned with sexual
behavior as well as with feeding.
As far as is known, olfaction serves a more important role than taste
in the courtship behavior of the American cockroach, Peripfoneta
americana. Females of this species emanate an odor which is highly stimulating to males. Upon perceiving the odor males become greatly excited
and may even attempt to copulate with a surface which has become
contaminated with the odor. The substance is truly an attractant which
acts in the gas phase and enables the male to locate the female. The
odor is perceived through receptors located on the antennae; antennaless males are quite incapable of being excited. The cockroach attractant
is the first one which has been studied quantitatively in terms of the