Demographic Analysis 
237 
Table 6. Estimated density of those insects most important in the diets of juvenile spiny 
lizards on the study area in Pottawattomee Co,. Kansas. 
Insect Density Period 2 Insect 
Percent of Volume of (mm^ of insect/ Density/Period 1 
Insect Order Lizard Gut Contents cm* of trap/hour Insect Density 
A. Period 1 — Jf. July to 11 August, 1972: 
Hymenoptera 
(ants) 
40.8 
0.0014 
Hymenoptera 
(others) 
11.1 
0.0089 
Homoptera 
14.3 
0.0002 
Orthoptera 
11.1 
0.0223 
TOTALS 
77.3 
0.0328 
B. Period 2 — 
■11 August to U October, 1972: 
Lepidoptera 
(adults) 
29.7 
0.0084 
Lepidoptera 
(larvae) 
22.2 
0.0030 
Arachnida 
19.7 
0.0017 
Hymenoptera 
(ants) 
12.4 
0.0012 
TOTALS 
84.0 
0.0143 
Hatchling Size and Fitness 
If seasonal increase in competition did 
cause greater density dependent mortality, 
was the mortality biased toward individuals 
of a smaller size? More importantly, did this 
bias result in a lower fitness? Of those liz- 
ards hatching early in the season, the larger 
hatchlings did not survive to the next breed- 
ing season at a rate significantly higher 
than that of the smaller hatchlings (Table 7). 
However, of those lizards hatching later in 
the season, when competition presumably 
was greater, the larger hatchlings survived 
at twice the rate of the smaller hatchlings. 
Aggressive dominance by larger hatchlings 
seemed to be resulting in a higher fitness 
later in the season when resource competition 
was likely to be more severe. 
Clutch Size, Egg Size, and Hatchling Size 
Has this seasonal increase in fitness of 
larger hatchlings occurred with sufficient 
Table 7. Survivorship of small and large 
hatchling spiny lizards on the study area 
in Pottowattomee Co., Kansas. Significance 
value designations same as in Table 4 and 
5. 
Survivorship of Late July Hatchlings until 
the Following Spring Breeding , 
Season: 
hatchling length 
(snout to vent in mm) 
20-23 
24-26 
# survivors 
12 
5 
# nonsurvivors 
39 
12 
proportion surviving 
0.24 
0.29 
Survivorship of Late August Hatchlings until 
the Followng Spring Breeding Season: 
hatchling length 
(snout to vent in mm) 
22-24 
25-26 
# survivors 
13 
15 
* 
# nonsurvivors 
48 
20 
proportion surviving 
0.21 
0.43 
