Welfare of Monarch Caterpillars and Host Plant Loss

Monarch butterfly caterpillars depend exclusively on milkweed plants, and their welfare is directly impacted by milkweed loss from agricultural herbicide use.

Key Facts

Monarch caterpillars eat only milkweed plants in the genus Asclepias
Glyphosate-tolerant crops allowed wholesale milkweed elimination from farm fields
Milkweed in the US Midwest has declined by over 50% since 1999
Female monarchs must find milkweed to lay eggs or waste reproductive energy searching
Non-native tropical milkweed can confuse migration timing and spread disease

Welfare Considerations

Monarch caterpillars that run out of milkweed starve to death. Females unable to find milkweed for oviposition expend enormous energy in fruitless searching, becoming depleted before finding suitable plants. The stress of inadequate host plant availability affects the entire monarch population lifecycle. These welfare harms occur at enormous scale given the collapse of milkweed populations. Restoring milkweed directly alleviates suffering for millions of individual caterpillars.

What You Can Do

Plant native milkweed species in your garden and community
Remove non-native tropical milkweed which can interfere with migration
Advocate for milkweed buffer strips in agricultural areas
Support organizations working to restore pollinator habitats across monarch range