Monarch Butterflies and Bt corn--Table 1

In the table below you can see the amounts of pollen from various corn sources that were tested on butterfly larvae. Pollen amounts are expressed as number of grains per square centimeter of leaf, with the number of grains per square inch of leaf given in parentheses underneath. The LD50, short for "lethal dose for 50 percent," is the amount of pollen that killed half of the caterpillars tested. A low LD50 indicates that the pollen is very toxic and not much pollen is needed to kill half of the caterpillars. A high LD50 indicates that the pollen is less toxic and a large amount is needed to kill half of the caterpillars.

 
Bt transgene butterfly species LD50* reduced feeding* no effect* source
Bt 176 Monarch 389
(2,509)
133
(8,580)
  Sears and Stanley-Horn, 2000)
Bt 176 Monarch 67
(432)
23
(148)
  Sears et al., 2001
Bt 176 Monarch   5 to 10
(32 to 65)
  Hellmich et al., 2001
Bt 176 Black swallowtail 613
(3,954)
    Zangerl et al., 2001
Bt 11 Monarch     more than 1,600
(more than 10,320)
Hellmich et al., 2001
MON810 Monarch     more than 1,600
(more than 10,320)
Hellmich et al., 2001
DBT418 (no longer available) Monarch     more than 1,600
(more than 10,320)
Hellmich et al., 2001
CBH351 (StarLink, no longer available) Monarch     1,001 to 1,600
(6,456 to 10,320)
Hellmich et al., 2001
TC1507 (Herculex, not yet available) Monarch     1,001 to 1,600
(6,456 to 10,320)
Hellmich et al., 2001

* Pollen amounts are expressed as number of grains per square centimeter of leaf, with the number of grains per square inch of leaf given in parentheses underneath.

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