excerpt from Science Daily above-
If one is planting milkweeds for monarchs, one might want to consider spacing them out. Spacing them out as opposed to planting them in groupings is believed to help reduce predation of eggs, larvae, and caterpillars.Intense deforestation in Mexico could ruin one of North America’s most celebrated natural wonders  the mysterious 3,000-mile migration of the monarch butterfly. According to a University of Kansas researcher, the astonishing migration may collapse rapidly without urgent action to end devastation of the butterfly’s vital sources of food and shelter.
Taylor leads Monarch Watch, a program at KU dedicated to research, conservation and education about the butterfly. Since 1992, Monarch Watch has tracked populations at the Monarch Biosphere Reserve, a 217-square-mile area in central Mexico that is the winter home for millions of migrating butterflies from across the continent.
In spite of its protected status, the isolated reserve is suffering from illegal logging driven by soaring prices for lumber in Mexico. This logging, once sporadic, has increased in recent years and now is threatening the very survival of the butterflies. Over the past two winters, millions of monarchs have died from exposure to wind and cold temperatures in clear-cut areas. Monarch Watch estimates half of the reserve needs reforestation.
“it's a remote area, and it's difficult to police,â€
I'm going to take my time to read over the info you posted.
milkweed. The monarchs had no trouble finding it and my kids and I have been raising caterpillars indoors every summer for the last three years. The number of butterflies we've released have increased each year -- last autumn, we raised and flew 23, plus 5 confirmed hatchlings outside from our little corner of NJ. 
I'm pretty sure my current volunteer is sp. (common milkweed)....