1968] 
Barth — Behavior of Gromphadorhina 
127 
within a few seconds, and the pair remained in the opposed position 
throughout the period of copulation. 
The activities of the first courting pair aroused the other males 
sufficiently so that only brief contact with a female was necessary 
for release of the walking and hissing activities of the male. During 
this period of heightened activity, a number of males walked about 
hissing even though not in contact with females. If such a male did 
contact a female he immediately attempted to copulate. Females 
usually fled from such males. 
Observations on four successful copulations suggest that several 
seconds may normally be required to achieve a satisfactory genital 
connection. During copulation attempts, the female may be pushed 
forward several inches by the male’s vigorous backing movements. 
Copulating pairs remain quiescent even though other animals may 
crawl over them. Males wave their antennae quite actively during 
copulation. Females wave theirs much less actively. In one case 
a copulating pair was disturbed by the observer after about 15 min- 
utes and the female ran off dragging the male behind her as in other 
cockroach species, even though in this case the male was much the 
heavier of the two. Copulation last a remarkably short time for so 
large a species, no more than twenty to thirty minutes (data from 
three copulations). These females were found to contain spermato- 
phores at the termination of copulation so it may be concluded that 
these were normal copulations. 
All successful copulations were preceded by long periods of gentle 
mutual antennal fencing and body stroking. Thus it seems highly 
probable that tactile stimulation resulting from antennal contact 
with a female is the normal releaser of the male’s courting activities 
in quiescent males, and that antennal fencing promotes sexual re- 
ceptivity in females. No male-male courtship sequences were ob- 
served. It seems quite possible that differences in the type of tactile 
stimulation resulting from antennal fencing between two individuals 
may alone be sufficient to determine subsequent behavior. As we have 
seen, the vigorous antennal fencing following male-male contacts is 
invariably followed by aggressive behavior, whereas the more gentle 
antennal fencing following male-female contacts is followed by court- 
ship behavior. The long-laterally projecting sensory hairs on the 
antennae of the male may indeed be tactile receptors specialized for 
precisely this purpose, i.e., the detection of different intensities of 
tactile stimulation. This hypothesis might be tested by subjecting 
males to various types of artificial tactile stimulation. Whether con- 
tact chemoreception plays a role in sex recognition is unknown. 
