Meeting Abstract
Milkweeds in the genus Ascleipas are the primary food source for monarch butterfly (Danaus plexippus) larvae which specialize upon, and derive their own chemical defense from, this toxic plant. Monarch butterfly numbers are decreasing with a steady annual reduction in numbers reaching their overwintering sites in central Mexico. While there are many contributing factors proposed for this reduction, one consideration consistently cited is reduced native food availability and increased planting of tropical milkweed in northern regions. This, coupled with global climate change, causes latency in migration and increases the instance of protozoan parasite infection, thereby contributing to reduced monarch butterfly numbers. Here we investigate the moisture and caloric content of multiple species of native temperate milkweed for comparison to the tropical species. These data provide a baseline for future plant-animal interaction studies while also documenting variation of these measures among members of a closely-related group of organisms with direct conservation implications. These data are also part of an ongoing study that links milkweed species to growth and development rate and digestive efficiency of monarch butterfly larvae feeding upon them.
