1976] 
Jackson — Phidippus johnsoni 
251 
do not taste bitter or noxious to humans (personal observation). 
When standing motionless on the ground, P. johnsoni tend to 
be rather inconspicuous, and their coloration may contribute 
to their crypticity in these circumstances, since many plants close 
to the ground have brightly colored leaves of size, shape, and 
color comparable to the abdomen of a P. johnsoni. In addition, 
since there is evidence that salticids possess color vision (Kaestner, 
1950), the abdominal markings may have a communicatory func- 
tion during type 1 courtship. 
Although it has frequently been suggested that during ani- 
mal courtship and mating the participating individuals are ex- 
posed to greater predation than at other times, data to support 
this contention are rare. Schaller (1972) observed an African 
lion prey on a courting reedbuck. Predators (Walker, 1964) 
and parasitoids (Cade, 1975) of some Orthoptera are attracted 
to male calling songs. The swarming flights of some Diptera, 
which can be interpreted as courtship, may be attended by heavy 
predation (Downes, 1969; Syrjamaki, 1966). Observations of 
this sort at least demonstrate that predation occurs on courting 
animals, but they are not sufficient to show that predation risks 
are elevated by courtship and mating. 
However, the arguments suggesting this hypothesis are rather 
convincing. Often it has been argued or implied that a mating 
or, especially, a courting individual is more conspicuous to preda- 
tors (Emlen, 1973; Morris, 1956; Platnick, 1971; Richards, 1927). 
During type 1 courtship, P. johnsoni males tended to be highly 
conspicuous to human observers, while they gestured with their 
forelegs and danced in front of females. When provided vege- 
tation and rocks, courting and mating pairs showed no tendency 
to seek cover (Jackson, 1976), courting and copulating some- 
times on the tip of a grass blade or the top of a rock. Species 
that remain relatively motionless during copulation may reduce 
their conspicuousness; however, copulating pairs of P. johnsoni 
were not motionless. While standing on the female’s dorsal 
surface, the male applied his paired copulatory organs, on the 
pedipalpi, one at a time to the female’s copulatory openings on 
the ventral side of her rotated abdomen. In addition to the move- 
ments involved in switching palps, the male engaged intermit- 
tently in postmount courtship, consisting of various stroking 
and tapping motions (Jackson, 1976). 
