THE LIFE-CYCLE OF THE SPIDER 
PHIDIPPUS COCCINEUS (SALTICIDAE) 
UNDER LABORATORY CONDITIONS* 
By Beatrice T. Gardner 
Department of Psychology, University of Nevada 
The jumping spider, P. coccineus, spends the winter in penultimate 
instar within a heavy hibernating web under stones. Usually, the 
spider undergoes its final molt just before it emerges, in April or in 
May, and resumes its nomadic bushtop existence. Mature males 
appear before the females do. In the spring of 1967, for example, 
twenty spiders were collected during the first week of April : seven 
of these were mature males, three were mature females, and the re- 
maining ten were females in the penultimate instar that became 
mature between 12 April and 23 April. The earlier date of reaching 
maturity for males yields a chi-square of 7.9, df— 1, p< .005. Court- 
ship and mating occur in late spring and early summer, but after 
mid-July adult specimens of P. coccineus are very difficult to find, 
although spiderlings of that species are abundant. 
For several years, we have observed that spiders overwintering in 
the laboratory, with continued warmth and abundance of prey, molted 
abnormally early and showed a striking concordance on this anoma- 
lous date of reaching maturity. Furthermore, even though the final 
molt is some three months premature, the males still became mature 
between one and two weeks ahead of the females. The spiders that 
matured early also died early and, in 1967, over half were dead 
before spiders that had spent the winter in the field began to emerge. 
Table 1 presents these data for 52 spiders which spent the winter in 
the laboratory. These spiders came from the same population as the 
20 that became mature by 23 April. 
A similar phenomenon has been observed in the reproductive be- 
havior of Phidippus apache anus. Under field conditions, these spiders 
mate in October-November, and the gravid female spends the winter 
in a heavy web under stones. Although the dates for egg-laying and 
hatching under field conditions are not known, it seems likely that 
these events do not occur until spring. At any rate, spiderlings of 
this species first appear in June, only a few weeks before those of 
P. coccineus. Four gravid females taken to the laboratory laid their 
*This research was supported by Public Health Service Research Grant 
MH-08938 from the National Institute of Mental Health. 
* Manuscript received by the editor May 22, 1967 
104 
