Table 1.
Comparison of survivorship and growth for Monarch larvae exposed as first or third instars to Bt11 and non-Bt pollen on caged milkweed (A. syriaca) plants in Ontario
| Response variable | First instars mean (SE)
|
Third instars mean (SE)
|
||||
|---|---|---|---|---|---|---|
| Bt11 | Non-Bt | P | Bt11 | Non-Bt | P | |
| Survival (in field), % | 84.4 (3.8) | 80.6 (3.4) | 0.47 | 91.7 (2.0) | 87.8 (2.8) | 0.46 |
| Leaf feeding/larva, cm2 | 1.7 (0.3) | 1.0 (0.1) | 0.32 | – | – | 0.25 |
| Development* | 2.4 (0.1) | 2.1 (0.1) | 0.40 | 4.2 (0.1) | 4.0 (0.04) | 0.34 |
| Weight gain/larva† | 20.4 (1.1) | 15.6 (1.8) | 0.37 | 15.1 (0.9) | 10.8 (1.5) | 0.55 |
| Survival (to pupation), % | 59.4 (5.1) | 57.4 (6.2) | 0.70 | 73.3 (3.4) | 63.3 (6.2) | 0.67 |
| Days to pupation‡ | 16.1 (0.3) | 16.3 (0.3) | 0.40 | 11.6 (0.2) | 12.1 (0.4) | 0.75 |
| Pupal weight, mg | 1280 (24.5) | 1246 (37.1) | 0.65 | 1201 (24.7) | 1147 (34.6) | 0.97 |
| Emergence (adults), % | 80.0 (6.0) | 95.2 (2.3) | 0.07 | 80.2 (3.7) | 76.2 (6.1) | 0.86 |
| Adult weight, mg | 534.1 (12.2) | 522.2 (13.2) | 0.33 | 474.9 (11.1) | 467.8 (15.4) | 0.33 |
| Adult wing length, mm | 52.7 (0.4) | 52.0 (0.6) | 0.67 | 50.9 (0.4) | 49.8 (0.5) | 0.67 |
*
Day 5 avg instar/day 0 avg instar.
†
Day 6 avg wt/day 0 avg wt.
‡
Days to pupation from the beginning of the exposure period.