1984] 
Wise — Phenology of filmy dome spider 
271 
Statistical analyses of the results of all studies were done with the 
UCLA BMDP programs, converted for use on Cyber computers by 
the Northwestern University Computing Center. 
Results 
Phenologieal Patterns in Maryland Populations 
Two peaks in adult abundance each season characterized the Lib- 
erty population (Fig. 1). Seasonal changes in the size-composition 
of both populations, particularly at Liberty, were similar to those 
found in the Michigan study (Figs. 2, 3; Wise 1976). The persistence 
of relatively high numbers of immature stages during the summer, 
and the absence of intermediate stages at the end of June, provide 
evidence of a polymorphic phenology: some progeny of the spring 
adults apparently over-wintered as juveniles, whereas others devel- 
oped rapidly and molted to adulthood between the end of July and 
the first part of September. Average adult carapace width was 
always significantly smaller in summer than spring (Table 1), addi- 
tional evidence that summer-maturing adults developed rapidly 
within a single season and were not the offspring of the previous 
summer’s adults. 
Females that matured in the spring laid more, but smaller, eggs 
than summer-maturing spiders (Table 1 ). Fecundity differences such 
as these could reflect different seasonally adaptive reproductive 
behaviors, or more simply, could have resulted entirely from repro- 
ductive parameters being correlated with female size. This possibility 
was examined. Analysis of the 1982 Patuxent data revealed statisti- 
cally significant correlations between number of eggs in the first sac, 
egg diameter and female carapace width. Stepwise multiple linear 
regression of the pooled seasonal data indicated that number of 
eggs was significantly related to both female size and mean egg size 
(R = .52). Most of the variation in number of eggs laid could be 
explained by the correlation with carapace width; addition of egg 
size as an independent variable increased the value of R by only .05. 
In a similar analysis with egg size as the dependent variable, egg 
number was the only statistically significant independent variable. 
Seasonal differences in reproductive parameters were then re- 
examined by comparing the adjusted means through ANCOVA of 
the appropriate regression equations. Differences between spring 
