Table 2.
Mean 96-h larval weight (mg), standard error (SE), and treatment sample size (n) for first instar D. plexippus after exposure to milkweed leaves with no pollen and leaves with various levels of pollen from event 176 (Cry1Ab) hybrids, and near-isoline hybrids
| Trial* | n | SE | No pollen | Mean pollen levels (grains/cm2)
|
41–80 Bt | 81–130
|
|||
|---|---|---|---|---|---|---|---|---|---|
| 5–10 Bt | 11–20 Bt | 21–40 Bt | Non-Bt | Bt | |||||
| 1 | 12 | 1.1 | 11.5a | 7.3ab | 3.6bc, 2.2cd | 1.8cde | 1.1de | 11.8a | 0.7e |
| 2 | 24 | 1.1 | 15.1a | 10.3bc | 6.2cde, 5.0de | 3.0def | 2.3ef | 15.0ab | 1.7ef |
| 3 | 12 | 1.2 | 9.4ab | 5.7bc | 3.5dc | 1.8de, 1.6de | 1.3de | 14.7a | 0.7de |
| 4 | 12 | 1.2 | 17.8a | 15.1a | 6.1b, 2.4bc | 1.8c | 1.2c | — | — |
| 5 | 12 | 1.2 | 20.1a | 15.4a | 4.0b, 3.6b | 2.1b | 1.0b | — | — |
| 6 | 12 | 1.2 | 9.5ab | 5.9ab | 3.0bc | 2.2bc, 3.1abc | 1.4bc, 1.9bc | 12.7a | 1.8bc |
Means within a trial with the same letter not significantly different (Tukey's test, P < 0.05). Assigning treatments to pollen-level categories sometimes resulted in two means per trial by level combination.
*
Non-Bt and Bt Hybrids used in each trial include: (Trial 1, 2657, 2657Bt), (2, 4273, Maximizer 88), (3, 4494, Maximizer 454), (4, 5, and 6, 4394, Maximizer 21).