I was excited to stumble across a cluster of Large Milkweed Bugs (Oncopeltus fasciatus) last Friday as I was exploring at Occoquan Bay National Wildlife Refuge. It had been several years since I had last seen these colorful little bugs that not surprisingly were gathered together on milkweed pods. There are so many cool insects that are associated with milkweeds that I often stop to examine the plants whenever I come upon them.
A little over nine years ago, I studied these bugs pretty closely and documented their stages of development in a posting that I called Life phases of the large milkweed beetle. Be sure to check it out for more information and fascinating photos of these colorful little bugs.
The short version is that as a “true” bug, milkweed bugs undergo incomplete metamorphosis. They go through a series of nymph stages, known as instars—the large milkweed bug has five instars. At each stage, the bug is covered by an inflexible exoskeleton that constrains its growth. Periodically it bursts out of the exoskeleton and can grow to twice his size as the new exoskeleton develops and hardens.
If you look closely the image, you will see that there are milkweed bugs at various stages of development. The youngest ones are smaller and are completely red. In some of the older ones you can see the development of tiny black wing pads. The orange and black one at the top of the group appears to be an adult.
Every time that I see this combination of bright red and green, my mind immediately thinks of Christmas. However, I doubt that anyone would choose to feature this image on their annual Christmas card.
© Michael Q. Powell. All rights reserved.
Mike Powell 