Oncopeltus fasciatus was the first insect that I handraised in my recent and limited experience with bugs, so I got to know these guys well.
adult female Oncopeltus fasciatus:
It was an Oncopeltus fasciatus named Angel who started my bugsession and caused me to fall in love with milkweed bugs with other insects to follow. Angel (mature adult male with mate) came home with me on a milkweed plant purchased at a local nursery on October 22, 2017. I overwintered him, his wife, and a few additions, and he lived until May 2, 2018, a nice long milkweed bug life.
Angel and his first wife, November 2017:
I later raised milkweed bugs from eggs to adult, mostly Oncopeltus fasciatus, but also Oncopeltus sexmaculatus and Lygaeus kalmii.
I am interested in creatures who use and who depend on milkweed, and I believe such creatures are in decline because of loss of milkweed habitat.
The only difficult part of raising milkweed bugs is maintaining fresh, healthy milkweed plants year-round. (See my article on raising milkweed beetles: https://bugguide.net/node/view/1715743
.) I had to drive all over Texas to purchase plants when they became available.
My overwintering milkweed bugs were kept loose on plants. These guys fly well, but generally stay on their plants overwinter as long as the plants are healthy. I released my overwintered milkweed bugs in spring as soon as I got a good milkweed patch planted in the ground.
To house overwintering adults, I set down several gallon-sized milkweed plants (Asclepias curassavica) on tarp in front of a large window to allow for sunlight and fresh air.
My overwintering adults often mated, but never laid eggs. They often remained in copula from evening through the following morning. Perhaps she is acquiring nutrients or perhaps she is storing sperm for later? They seemed to find comfort in remaining in copula and often did so on the coldest nights. (They were indoors, but I have no AC/Heat, so winter nights are quite cool, but the bugs are protected from rain, predators, strong winds, and the like.)
For nymphs, large butterfly cages must be used to contain the bugs, as their wanderlust gets the better of them. I put gallon-sized and four-inch potted plants inside the cages for them. Cages should be cleaned daily and plants kept watered and fresh.
Oncopeltus species have a strong preference for seedpods (they are Lygaeidae, after all), so it's important to keep plants with seedpods as well as flowers for nectar. I never observed Oncopeltus fasciatus eating leaves, but Oncopeltus sexmaculatus nymphs absolutely eat leaves. I usually saw their leaf markings before I saw the bugs.
Milkweed bugs will also consume nectar from other flowers. I have seen them eating on a variety of flowers in my backyard.
Oncopeltus fasciatus on cantaloupe flower and Passiflora (hybrid species):
I discovered that my O. fasciatus love blanched almonds (slightly soft) and will eat a few other fresh, raw, organic nuts that I crushed for them.
I use plastic bottle caps to make water dishes and use only fresh purified water. Water must be kept shallow, especially if there are nymphs around. Adults don't generally drown, but nymphs can, so it is essential that the water level be kept to just enough for the bugs to drink. My bugs drank often from these dishes. In addition, I misted daily with a fine mist spray bottle.
My milkweed bugs generally laid their eggs on the underside of milkweed leaves, or around seedpods when they are available. If the eggs end up in the wrong place, use a soft paintbrush or toothpick or popsicle stick (depending on size of cluster) to move eggs and place them on a milkweed leaf. They are a bit sticky and will stick to the leaf in a cluster. The eggs usually hatched in about 6 or 7 days, depending on seasonal conditions.
The nymphs go through five distinctive instars. They generally hang upside down on a leaf or stem to moult.
Click the thumbnail to see a series of moulting images as this Oncopeltus fasciatus nymph moults from fourth-instar to fifth-instar:
Fifth-instar nymphs hang on to leaves or stems to moult into adults.
Click the thumbnail to see a series of Oncopeltus sexmaculatus moulting to adult:
Unfortunately, no matter how well you feed these guys, they will occasionally eat each other. This is more common in nymphs.
Nymphs might eat the same instar and smaller, attacking living comrades.
Oncopeltus fasciatus 4th-instar eating 4th-instar (Click each to see series:)
I only saw one case of adult eating adult (O. fasciatus), and, occasionally, an adult eating a nymph.
Click to see description of adult Oncopeltus fasciatus eating fellow adult:
If I have a healthy milkweed patch ready, I will get spring migrating Oncopeltus fasciatus around March 22 to March 24. Most stay only a few days and migrate on, while a few will choose to remain for summer. Lygaeus kalmii are rare where I am, but I usually get a small handful each season. Oncopeltus sexmaculatus occur a bit south of me, so the ones I've had came home with me on plants I bought at area nurseries.
Caring for Milkweed Bugs
If healthy milkweed plants are available, care for the bugs is easy. You'll want to have a supply of large butterfly cages, mist bottles, sticks for moving and handling bugs, bottle caps for water dishes, purified water, and supplemental foods like blanched almonds. You might need grow lights, depending on how much natural light you can get and the season. You will get to know the bugs quickly and quite well, and they will teach you a lot.
Nymphs can be difficult to move because they panic and run. I use toothpicks for tiny ones and milkweed leaves for bigger ones to lure them onto the leaf and place them back on their plants. You can also use little slips of paper. Older nymphs and adults will readily climb onto sticks. I kept slim wooden chopsticks and skewer sticks all around for luring and moving bugs of different sizes. When you finally get your tiny little nymph on the plant he's supposed to be on, especially near a seedpod or blossom, he will be so grateful and will often start munching right away.
Overwintering adult bugs indoors, in my opinion, can help them survive. They must be released in spring so they can migrate and reproduce. I recommend establishing a good patch of milkweed (I buy established plants and make a quick garden as soon as milkweed becomes available in nurseries) and then releasing the bugs onto their new plants.
If you release them early in the morning while they are still sleepy, you can carry each plant full of bugs outside and just place the potted plant (still in pot) securely in the garden patch so your bugs can crawl off at their leisure. Make sure the plant is secure and won't fall over. I just keep watering the potted plant along with the in-ground milkweed until all bugs have crawled off, however long it takes.
It's important that your garden milkweed be pollinated because milkweed bugs need seedpods. I attract bees and other pollinators with additional flowers and I provide bee fondant every reasonable day throughout the entire winter. On milder days, I get bees by the hundreds. Of course, if you're much braver than I am, you can try hand-pollinating your milkweed. I haven't the eyesight, the manual dexterity, or the audacity to do that.
Milkweed bugs are exceptionally beautiful and sweet and endlessly interesting to watch. I hope you enjoy them as much as I do, and if I can answer any questions about rearing them, please ask away.
One of my babies named Eve: