176
V. G. DETHIER
and other species in painstaking detail and have reconciled divergent
points in earlier descriptions. The behavior is described as follows. A
male coming into contact with another individual stops and investigates
the other with his antennae. If the other is a male also, either or both
stand high on their tarsi and rock from side to side; if, on the other
hand, the stranger is a female, the two individuals stroke one another's
antennae in a fencing or sparring action. Next the male turns so that
he presents his terminal segments toward the female and then elevates
both pairs of wings to an angle of approximately ninety degrees. In so
doing he extends his abdominal segments and exposes two pairs of
glands on the seventh and eight abdominal tergites. A responsive female
actually feeds on the products of these glands. After a feeding interval
or from three to seven seconds copulation takes place. Courting in this
species consists then of antennal fencing, raising of the wings of the
male, and feeding by the female. The most invariable response of the
sexually activated male is raising of the wings. Unlike some mosquitoes
and promiscuous Drosophila
males, cockroaches are not always in a
mating state. The first stimulus to courting response appears to be
antennal sparring. Roth and Wills have investigated this behavior in
great detail.
Sexually active males of this species can discriminate between adult
males and females, but only upon contact. Neither sex is attracted by
the other from a distance; contact is necessary. The basis of discrimination upon contact is chemical. Sexually active males will not give a
courting response when stimulated mechanically in the close proximity
of females. Such an experiment indicates that the response is not dependent upon an integration of two stimuli of which one is olfaction and
the other touch; true chemical contact is required. While the active substance is present in greatest amount on the antennae of females, it also
occurs on other parts of the body and can be rubbed off on copulating
males, so that they in turn exert some stimulation on other males. This
influence again is exercised through contact chemoreception, because
courting in one pair does not induce courting in idle passers-by; nor does
the act of copulation alone make a male sexually attractive to others.
The importance of antennal sparring is largely chemical; but in all probability movement and activity have some value, because although males
will court antennaless females and dead females the percentage of response on the part of the males is always less. The sex attraction occurs
on the antennae of young adult females, females which are carrying
eggs and cannot copulate, full-grown female and male nymphs, newly
emerged males, and both male and female adults and nymphs of B.
orientalis. The antennae of Periplaneta americana possess little stimulat-
V. G. DETHIER
and other species in painstaking detail and have reconciled divergent
points in earlier descriptions. The behavior is described as follows. A
male coming into contact with another individual stops and investigates
the other with his antennae. If the other is a male also, either or both
stand high on their tarsi and rock from side to side; if, on the other
hand, the stranger is a female, the two individuals stroke one another's
antennae in a fencing or sparring action. Next the male turns so that
he presents his terminal segments toward the female and then elevates
both pairs of wings to an angle of approximately ninety degrees. In so
doing he extends his abdominal segments and exposes two pairs of
glands on the seventh and eight abdominal tergites. A responsive female
actually feeds on the products of these glands. After a feeding interval
or from three to seven seconds copulation takes place. Courting in this
species consists then of antennal fencing, raising of the wings of the
male, and feeding by the female. The most invariable response of the
sexually activated male is raising of the wings. Unlike some mosquitoes
and promiscuous Drosophila
males, cockroaches are not always in a
mating state. The first stimulus to courting response appears to be
antennal sparring. Roth and Wills have investigated this behavior in
great detail.
Sexually active males of this species can discriminate between adult
males and females, but only upon contact. Neither sex is attracted by
the other from a distance; contact is necessary. The basis of discrimination upon contact is chemical. Sexually active males will not give a
courting response when stimulated mechanically in the close proximity
of females. Such an experiment indicates that the response is not dependent upon an integration of two stimuli of which one is olfaction and
the other touch; true chemical contact is required. While the active substance is present in greatest amount on the antennae of females, it also
occurs on other parts of the body and can be rubbed off on copulating
males, so that they in turn exert some stimulation on other males. This
influence again is exercised through contact chemoreception, because
courting in one pair does not induce courting in idle passers-by; nor does
the act of copulation alone make a male sexually attractive to others.
The importance of antennal sparring is largely chemical; but in all probability movement and activity have some value, because although males
will court antennaless females and dead females the percentage of response on the part of the males is always less. The sex attraction occurs
on the antennae of young adult females, females which are carrying
eggs and cannot copulate, full-grown female and male nymphs, newly
emerged males, and both male and female adults and nymphs of B.
orientalis. The antennae of Periplaneta americana possess little stimulat-