Moths Vibrate Their Genitals to Avoid Bats National Geographic Why does my butterfly keep hanging upside down and vibrate? Ever notice a monarch butterfly vibrating its wings? This isn't just random behaviorit's a survival strategy called Shivering. Especially when temperatures drop, monarchs vibrate their wings to generate heat and warm Butterflies vs Moths: What are the differences? Brandywine Conservancy and Museum of Art Love is in the air: how butterflies date Natural History Museum Lepidoptera Wikipedia