1979] 
Dunkle — Xenos pallidas 
331 
Data on parasite position in the host was divided into 5 categories: 
(1) Only females in host, (2) Only males in host, (3) Equal numbers of 
both sexes in host, (4) Fewer males than females in host, and (5) More 
males than females in host. These categories had subcategories based 
on the sex combination of the parasites in each host. 
Parasite position with only female Xenos pallidus in the host: 
Table 3 shows that as the number of female parasites in a host 
changes, the location of the parasites under the tergites of the host 
significantly changes (p<0.001). When only one female is present in a 
host, 90.8% of the dorsally located females had a preference for the 
fifth tergite. As the number of females in a host increases, the propor¬ 
tion under tergite 5 decreases, while the proportion under tergite 4, 
and possibly tergite 6, increases. Only 3 females were located under 
the third tergite in this category. 
Table 3. Contingency table for correlation between number of female Xenos pallidus 
in male Polistes annularis and the tergite of the abdomen where the parasites were 
located. Parentheses indicate percentages of each row. C = .41, X 2 = 78.4, significant 
at p <0.001, DF = 
6, N = 396. 
Number of 
females in 
host 
Number of Abdominal Tergite 
3 and 4 5 6 
Total 
i 
12 ( 5.0) 
217 (90.8) 
10 ( 4.2) 
239 
2 
18 (19.2) 
69 (73.4) 
7 ( 7.5) 
94 
3 
10 (29.4) 
23 (67.7) 
1 ( 2.9) 
34 
4, 5, or 6 
16 (55.2) 
9 (31.0) 
4(13.8) 
29 
Total 
56 
318 
22 
396 
Just 45 females in this category were located under the sternites, 
compared to 396 under the tergites. If females located ventrally are 
added to Table 3, the change in parasite location is still significant 
(p<0.001). Most of the females (32 / 45) under the sternites were under 
the fifth sternite. As the number of females in a host increases, the 
proportion under sternite 5 increased similar to the proportion under 
tergite 4. 
Thus intrasexual competition causes a tendency for the “losing” 
females to be shifted first to the fourth tergite, then others to the fifth 
sternite. One might expect the preferred fifth tergite position to be 
filled before the other positions were accepted. If we assume that 2 
females fill the fifth tergite position, only 29 of 79 hosts with 2 or more 
