1967] 
Gardner — Life-cycle of Phidippus 
105 
eggs between 12 December and 30 December; these eggs hatched in 
January and mobile spiderlings emerged from the nest in February. 
Parenthetically, two of the early maturing P. coccineus females were 
mated with early maturing males; the eggs were laid in February, 
and the spiderlings emerged in March. 
The fact that both sexual maturity and death in P. coccineus were 
accelerated by overwintering in the laboratory implies that, like the 
proverbial candle that cannot burn at both ends, the life span of this 
spider depends more on metabolic processes than on calendar time. 
By accelerating maturity with laboratory maintenance conditions, 
it is possible to bring together young adults of P. coccineus and P. 
apacheanus. Thus, the technique could provide the basis for a study 
on mechanisms of reproductive isolation in these two species. Nor- 
mally, the adults of apacheanus and coccineus appear in the same 
habitat at different times of the year, so that the time at which each 
species is courting does not overlap (Gardner, 1965). 
Finally, the fact that the spiders had been under constant condi- 
tions of warmth and abundance of prey for about three months with- 
out molting, while during July-September the intermolt interval for 
25 P. coccineus was 27 =+r 5.5 days, and that they subsequently 
molted within a relatively short time (for males, 3 January ± 13 
days, and for females 13 January ±11 days), suggests the following 
TABLE I 
Maturity and Survival of P. coccineus Overwintering in the Laboratory 
(Winter '66-’67 : N- 52; 26 became adult $ $ ; 11 became adult $ $ ; 
15 died before maturity.) 
Percentage 
of group reaching: 
Penultimate Instar Adult Stage* Death** 
$ $ 
$ $ $ $ 
$ 5 $ $ 
$ $ 
Before the 
1st day of: 
Oct. 
0 
11% 
Nov. 
96% 
89% 
Dec. 
4% 
0 
J an. 
36% 
0 0 
0 
Feb. 
64% 
100% 28% 
11% 
March 
32% 
22% 
April 
8% 
22% 
*The $ $ - 
$ $ difference 
is significant at p = 
04, Fisher’s exact 
method. 
**32% of the males and 
44% of the females 
survived beyond 
April 1 
and were 
released in the field. 
