Table 3.
Summary of measures of viability of pure and hybrid crosses
| Cross type (n) | Eggs/ brood (SD) | Eggs/day* | % eggs hatching | % larval survival | Development time,† (days) | Sex ratio (female/total) |
|---|---|---|---|---|---|---|
| H × H (14) | 61 (26.0) | 2.6 ± 0.8 | 92.7 ± 3.3 | 66.7 ± 8.1 | 28.5 ± 0.9 | 0.49 ± 0.05 |
| E × E (12) | 38 (22.1) | 1.9 ± 0.4 | 90.3 ± 5.5 | 57.5 ± 12.3 | 29.8 ± 1.0 | 0.48 ± 0.06 |
| EH (12) | 46 (23.6) | 1.8 ± 0.6 | 83.7 ± 9.8 | 64.1 ± 9.8 | 29.3 ± 0.8 | 0.48 ± 0.06 |
| HE (8) | 55 (35.0) | 2.4 ± 1.2 | 89.2 ± 4.7 | 53.8 ± 12.7 | 29.2 ± 1.1 | 0.45 ± 0.06 |
| BC1 (E) (7) | 70 (19.7) | 2.8 ± 1.2 | 87.3 ± 9.0 | 67.8 ± 7.8 | 30.0 ± 1.0 | 0.51 ± 0.06 |
| BC1 (H) (10) | 41 (23.1) | 2.2 ± 1.2 | 90.0 ± 7.1 | 62.3 ± 4.7 | 28.9 ± 1.2 | 0.53 ± 0.07 |
| BC2 (16) | 44 (24.2) | 2.0 ± 0.7 | 85.7 ± 12.3 | 53.8 ± 14.9 | 28.1 ± 0.6 | 0.44 ± 0.06 |
| F2 (7) | 40 (16.3) | 1.5 ± 0.7 | 92.0 ± 9.6 | 84.5 ± 6.7 | 30.2 ± 2.0 | 0.51 ± 0.08 |
| F3+ (6) | 46 (15.4) | 2.5 ± 1.2 | 99.3 ± 1.8 | 83.4 ± 10.0 | 28.1 ± 0.7 | 0.50 ± 0.08 |
The female parent of a cross is given first. Averages and 95% confidence limits of number of eggs/day, egg hatch, larval survival, developmental time, and sex ratio are taken over all hybrid and control crosses in each category. The two different F1 crosses (H × E and E × H) were examined separately. Similarly, backcross broods (BC1) were grouped into crosses between F1s and eratos [BC1 (E)] or between F1s and himeras [BC1 (H)]. All BC2 (crosses between BC1 and pure individuals) and F3+ (crosses between F2s and pure types) broods were evaluated together. Egg hatch and larval survival for all individual crosses is presented in Fig. 1.
In comparisons of hybrid and control broods reared together, only F2 crosses laid significantly fewer eggs/day relative to erato and himera (t = 2.547, P = 0.04, df = 6).
Egg-adult developmental time for each cross was estimated using the mean developmental time of five male and five female butterflies.