1984] 
Wise — Phenology of filmy dome spider 
275 
Table 1. Differences between spring and summer in size at maturity and repro- 
ductive parameters of spiders from Patuxent and Liberty populations. Means ± s.e. 
are given with sample sizes in parentheses. The Bonferroni Multiple Comparison 
Test was used to examine the significance of seasonal differences for the Liberty 
population in 1980, and for Patuxent in 1981 and 1982. Differences between spring 
and summer in carapace width, egg number and egg size were all significant at p < 
.01 or greater. Means did not differ significantly between areas within the same 
season and year. Means also did not differ significantly between years, with the 
exception of male carapace width in the Liberty population between the springs of 
1980 and 1981 (p < .01). 
SPRING SUMMER 
Liberty Patuxent Liberty Patuxent 
1980 
1981 
1981 
1982 
1980 
1981 
1982 
Females 
Carapace (mm) 
1.36 
1.33 
1.42 
1.40 
1.15 
1.18 
1.22 
±.01 
±.01 
±.02 
±.01 
±.01 
±.01 
±.01 
(52) 
(27) 
(35) 
(93) 
(52) 
(71) 
(48) 
Number of eggs. 
63 
66 
50 
49 
first sac 
±6 
±3 
±3 
±3 
(9) 
(56) 
(15) 
(34) 
Egg diameter. 
.610 
.618 
.597 
.603 
.653 
.649 
.641 
first sac (mm) 
±.003 
±.007 
±.003 
±.005 
±.004 
±.006 
±.007 
(44) 
(25) 
(30) 
(57) 
(19) 
(17) 
(35) 
Males 
Carapace (mm) 
1.57 
1.47 
1.55 
1.29 
1.25 
±.01 
±.02 
±.03 
±.02 
±.05 
(10) 
(19) 
(11) 
(32) 
(9) 
in the season at Patuxent. For example, on 19 May 1982 only 30% 
of the Liberty population was mature, whereas at Patuxent over 
90% were adults. Also, mature spiders comprised a greater propor- 
tion of the summer population at Patuxent, suggesting that more 
progeny of spring adults developed rapidly at Patuxent than at 
Liberty. At the end of the season more of the population consisted 
of older juveniles at Patuxent than at Liberty. The accelerated phe- 
nology of the Patuxent population may have resulted, at least 
partly, from warmer web-site temperatures at this lower-elevation 
site (Table 3). The relative proportion of adults in the population 
throughout the season at Liberty more closely resembled the pat- 
tern in Michigan than did the pattern at the Patuxent site. 
Field Experiment 
On Day 0 (21 July) a total of 238 immature spiders, stages 2-4, 
occupied webs on the units. By the middle of September the total 
