Appendix B. Summary data distinguishing four ant species that visit the extrafloral nectaries of Ferocactus wislizeni, and reproduction on plants typically tended by those ants.
The Michaelis-Menten constant, b, indicates the number of workers necessary to incapacitate five caterpillars in 30 minutes. Maximum-likelihood estimates of b are provided for the number of ants on a plant prior to the addition of caterpillars (initial abundance) and for the maximum number of ants observed on the plant during the 30-minute trials in which ants attack those caterpillars. 95% confidence intervals for each b are indicated in parentheses. F is an estimate of plant protection, specifically the proportion of ten caterpillars killed within 30 minutes based on the number of ant bodyguards that typically visit a plant. Separate F values are provided for two time periods because the number of workers per visit differed. The bottom half of the table provides summary data regarding protection and reproduction of plants that are tended by each of the four species, tended by a mixed ant assemblage, and untended by ants on a majority of surveys. Standard errors are indicated, and number of plants is shown in parentheses. F values in the bottom half indicate mean protection for plants with different tending histories, and are weighted for visits by other ant species and untended periods.
| Ant characteristics (CI) | ||||||
b, from initial abundance |
5.1 (4.3–6.1) |
12.7 (9.6–16.8) |
5.1 (3.9–6.7) |
4.1 (2.7–6) |
||
b, from maximum abundance |
18.8 (15.7–22.4) |
31.3 (23.6–41.4) |
14.3 (10.7–18.8) |
9 (6.1–13.2) |
||
F, April–June |
0.58 (0.55–0.62) |
0.25 (0.21–0.30) |
0.58 (0.53–0.62) |
0.66 (0.59–0.72) |
||
F, June–September |
0.65 (0.62–0.68) |
0.36 (0.31–0.41) |
0.70 (0.66–0.74) |
0.76 (0.69–0.82) |
||
| Plants grouped by most common ant attendant (n) | ||||||
F, April–June |
0.48 ± 0.01 (97) |
0.30 ± 0.01 (8) |
0.48 ± 0.04 (7) |
0.49 ± 0.01 (29) |
0.32 ± 0.01 (47) |
0.15 ± 0.01 (54) |
Observed: Expected bud production |
1.03 ± 0.05 (97) |
0.86 ± 0.15 (8) |
1.03 ± 0.13 (7) |
1.09 ± 0.1 (29) |
0.98 ± 0.07 (47) |
0.74 ± 0.07 (54) |
F, June–September |
0.62 ± 0.01 (67) |
0.40 ± 0.03 (5) |
0.67 ± 0.02 (49) |
0.72 ± 0.01 (76) |
0.51 ± 0.03 (23) |
0.25 ± 0.09 (5) |
Reproductive units surviving (%) |
82.2 ± 2.9 (67) |
90.6 ± 7.5 (5) |
91.3 ± 2.2 (49) |
96.7 ± 1.4 (76) |
90.5 ± 3.5 (23) |
51.8 ± 22.0 (5) |
F, April–September |
0.56 ± 0.01 (80) |
0.34 ± 0.06 (4) |
0.52 ± 0.02 (16) |
0.57 ± 0.01 (50) |
0.44 ± 0.01 (69) |
0.22 ± 0.03 (10) |
Surviving: Expected reprod. units |
0.78 ± 0.05 (80) |
0.72 ± 0.25 (4) |
0.81 ± 0.09 (16) |
0.92 ± 0.05 (50) |
0.84 ± 0.05 (69) |
0.54 ± 0.16 (10) |