Do Monarchs Die Of Heat Stroke?

[pianopete]

We have been raising and releasing Monarchs all year with excellent results.... no losses from caterpillar to release of butterfly. However, this morning we experienced our first loss. Normally, a monarch emerges from the chrysalis, about 7 AM. Later, I take the mesh cage enclosure in which we keep here in the house, out on the patio around 10 AM to let them warm before releasing... the A/C keeps our house cool. This morning we had 5 healthy looking monarchs to release. I left them on the sunny patio in their mesh cage to warm, but when I went back to release them about 15 miunutes later, they were laying on the bottom of the cage. One was obviously dead, and the other four appear they will be dead before noon..... not good. I'm wondering if this morning I crossed some magic temperature threshold that they could not tolerate. This is south Florida, and the air temp on the patio was 85 F. Possibly where the cage was sitting the actual temp may have risen higher. I brought them back inside in hope of recuperation..... but it looks hopeless.

[Megathymus ursus]

85F is nothing. Now, if the temperature the monarchs were exposed to was like 100, you would have a point. Monarchs are superbly adapted to south FL (and southern CA) weather. Remember to NEVER leave butterflies or caterpillars in unprotected full sun.

Have you considered that they somehow were exposed to some toxin?