128 
Psyche 
[June 
MATING BEHAVIOR of GROM PHADORHI I/A PORTENTOSA 
? BEHAVIOR RELEASER (f BEHAVIOR 
MOTIONLESS 
ANTENNAL 
FENCING 
(if receptive) 
ANTENNAL 
FENCING + 
STROKING of 
cT's BODY 
TOUCHES ? with 
ANTENNAE 
ANTENNAL 
FENCING 
WALKING AROUND? 
with HISSING 
(Antennal Stroking of 
?'s BODY) 
(f a 9 ABDOMINAL TIPS OPPOSED 
r ° c ^e~si]r~ — BACKING + 
COPULATORY THRUSTS 
(Genital Connection) 
OPPOSED POSITION 
Figure 1. A summary of the mating behavior of Gromphadorhina por- 
tentosa, indicating the possible releasers for each step in the sequence. 
The possible role of chemical stimuli in the release of sub:equent 
steps in the courtship sequence is also uncertain. As noted above, 
there is a characteristic odor associated with the hissing male. This 
odor is apparent in all situations in which hissing occurs but this 
fact does not necessarily preclude the possibility that the odor has 
some effect on the level of sexual receptivity and subsequent behavior 
of the female, thus qualifying as a true male sex pheromone. Du- 
mortier (1965) reports that no odor perceptable to human olfactory 
receptors was associated with hissing in the closely related species, 
G. hrunneri. A schematic representation of the mating behavior of 
G. portentosa indicating the possible releasers of the various stages 
in the sequence is shown in Figure 1. 
