Common Milkweed Insects

Monarch butterfly (Danaus plexippus) caterpillars are probably the one insect most people associate with milkweeds (Asclepias spp.). But if you’ve ever grown or just observed milkweeds, likely you’ve encountered some other insects on those plants. Not many insects are able to feed on milkweeds. The sticky white sap that gives milkweed its common name and the leaves contain toxic chemicals (cardiac glycosides) to deter mammals and insects from feeding on the foliage. Only certain insects which have evolved to be able to deal with those chemicals without being poisoned can thrive on the plants, and have become specialists on milkweeds.

Other insects besides monarchs visit milkweed flowers.

The flowers and nectar of milkweeds, however, do not contain these chemicals so nectar-seeking bees, flies, and butterflies can pollinate the plants without being affected.

Milkweed bugs have bright red or orange aposematic (warning) coloration.

And just like the monarch caterpillars which sequester and concentrate the toxins in their own bodies, giving them a bitter taste and protection against predators, many other milkweed insects – including milkweed bugs, milkweed longhorn beetles, and milkweed leaf beetles – have developed ways for using the toxins in their own defense, too. The insects that have this ability typically have aposematic markings, or warning coloration, advertising their toxicity. This is why so many insects found on milkweed plants have conspicuous red or orange colors or markings. A few other milkweed specialists have developed ways to “eat around” the sap to avoid its toxic effects.

Another caterpillar that specializes on milkweeds is the milkweed tussock caterpillar or milkweed tiger moth, Euchaetes egle, in the family Erebidae, subfamily Arctiinae (formerly family Acrtiidae).  Found throughout eastern North America, this moth with a wing span up to 1¾ inches, has dull grey, mostly unmarked wings and a hairy yellow-orange abdomen marked with black dots. The female moth lays fuzzy white masses of eggs on the underside of the leaves.

The adult milkweed tussock moth has dull gray wings (L) and a yellow-orange abdomen marked with black dots (LC and RC). The female lays masses of white eggs on the underside of leaves (R).

Milkweed tussock moth caterpillars feed together in large groups in the early instars.

The gregarious early instars skeletonize whole leaves, feeding only on the tissues between the veins, thereby avoiding the copious latex sap. Initially the caterpillars with black head capsules are pale and hairless, and second instar caterpillars have sparse spines or hairs. By the third instar the caterpillars have thick tufts of black, white and orange (sometimes yellow) hairs covering the body. These larger caterpillars wander about so they may be seen alone or in small groups from mid to late summer on common milkweed (A. syriaca) and a few other plants. The older caterpillars sever major leaf veins to reduce the amount of latex sap encountered. Milkweed tussock caterpillar is seldom in competition with monarch caterpillars, as they generally feed on older shoots while monarchs prefer younger shoots. The mature larvae drop to the ground and produce a gray cocoon, incorporating hairs from the caterpillar, where they pupate to become adults or overwinter. This species has a single generation per year in the north (two or more in the south).

The small white eggs (L) hatch into small cream-colored larvae with black heads (LC) that develop hairs in the second instar (C) and by the third instar have thick tufts of hairs (RC) that are incorporated into the cocoon that protects the pupa (R).

Like the monarch caterpillar, this species also sequesters cardiac glycosides and retains them in the adult body. Since the primary predators of the moths are bats, which hunt at night using sound rather than sight to locate prey, the moths don’t need warning coloration. Instead the moth evolved to produce ultrasonic clicks from their tymbal organs which bats quickly learn is associated with a noxious mouthful and then avoid the moth as prey.

Large milkweed bug with mouthparts inserted into common milkweed seed pod.

There are two true bugs (family Lygaeidae, order Hemiptera) that are associated with milkweed mostly in late summer and fall, the large milkweed bug and the small milkweed bug. Both are gregarious, feeding exclusively on the sap and seeds of plants in the milkweed family and both have the aposematic colors of red and black. Although they will feed on young leaves, flowers, and developing pods, their preference is for the seeds, which provide the best growth and reproduction, and large congregations of all stages of the insects together can be seen on milkweed plants. Like all true bugs, they have sucking mouthparts to inject digestive enzymes into the plant tissue and then suck the liquefied plant material through their straw-like beak. Because of the length of their mouthparts they are only able to feed on the outside layers of seeds in each pod, leaving many interior seeds intact for plant reproduction. Females lay light lemon yellow eggs in crevices between the seed pods, depositing up to 30 eggs a day for about a month. The eggs change to a bright orange or red color before the nymphs hatch in a few days. The immatures (nymphs) resemble the adults, although the color pattern changes as they go through the five instars before molting to the adult stage. The nymphs remain together, feeding on the developing seeds, although they will scatter if disturbed. There is a single generation each year in Wisconsin. Both species sequester cardiac glycosides in their bodies so are poisonous to most predators.

Milkweed bugs do little damage to milkweeds so control is generally not required. Removing leaf litter and old stalks in the fall can help eliminate overwintering sites. If populations are very high on plants grown for their seeds, the bugs can be treated with insecticidal soap or synthetic chemicals.

Adult large milkweed bug.

The large milkweed bug, Oncopeltus fasciatus, grows up to ¾ inch long. The adults are orange-red with markings of two black triangles pointing forwards and backwards, separated by a prominent black bar through the middle of the wings. The black pronotum has orange-red margins. Adult males have a black band on the underside of the fourth abdominal segment while females have two black spots on that segment. The adults can be confused with the boxelder bug, but that insect is a little smaller, usually is not found on milkweed, and has a different pattern of black and red. Box elder bugs have three longitudinal red stripes on the pronotum, while the large milkweed bug has a red transverse band, and the boxelder bug has red edges rather than an X-like pattern. The nymphs have an orange body, with black legs, antennae, and wingpads which lengthen with age, and develop small black spots on the abdomen as they mature.

Large milkweed bug nymphs in a group on a milkweed seed pod (L and LC) and an individual nymph showing the black wingpads that will lengthen as it develops (RC). Pair of mating large milkweed bugs (R).

This species occurs from Central America to southern Canada, but does not survive the winter in cold locations like Wisconsin and has to re-invade from the south every year. Northern populations migrate over longer distances than southern and tropical populations, and movements correlate with flowering of milkweeds. The adults migrate south in the fall to overwinter in the southern Atlantic and Gulf coast states, then new generations gradually migrate north again in the spring and summer. In mild climates there can be up to 3 generations per year, but just a single generation is produced in Wisconsin. This species prefers common milkweed, but will feed on other species of Asclepias, and even other plants in the same family if its preferred food is unavailable.

Adult small milkweed bug.

The small milkweed bug, Lygaeus kalmii, only grows up to ½ inch long and are black with a large red X-shape on the back and white margins on the wings and sometimes small white spots in the middle of the wings. There is a red band on the pronotum instead of orange margins as on the large milkweed bug. The nymphs look very similar to large milkweed bug nymphs but are a brighter red and have two diagonal black markings on the pronotum. This species overwinters in Wisconsin as an adult. Although they feed primarily on seeds, adults will sometimes feed on monarch butterfly caterpillars or pupae or other insects trapped in milkweed flowers, or consume nectar from various flowers. This species occurs throughout North America, and is frequently seen on a variety of species of Ascelpias, including swamp milkweed (A. incarnata).

Adult red milkweed beetle.

Two beetles (Order Coleoptera) are common on milkweed. The 26 different milkweed longhorn beetles (Tetraopes spp. in the family Cerambycidae) each prefer a different species of milkweed. Of the 13 that occur in the US, only three species occur in the east, and the most common species in Wisconsin is the red milkweed beetle, T. tetraophthalmus.

The scientific name tetraophthalmus means “four eyes”, referring to the way each compound eye is divided into two by the antennal base.

The scientific name tetrophthalmus means “four-eyed” referring to the way each compound eye is completely divided by the base of the antenna. The adult is orange-red with four black spots on the elytra.

Mating red milkweed beetles.

The adults eat milkweed leaves, buds, and flowers, and reduce the flow of the sticky milky latex (which could gum up their mouthparts) by severing leaf veins below their feeding site.  The sap drains from the leaf, and the beetle can feed on the drained area beyond the cuts. The females lay their eggs on stems near the ground or just below the surface. The larvae hatch and bore into the stems to travel downward to the roots or go through the soil directly to the roots to feed on the roots through early fall. They overwinter in the roots, pupate in earthen cells in the spring and the adults emerge in early summer, coinciding with hostplant flowering. Common throughout North America from Texas into Canada, it can be very common where its preferred host plant, common milkweed, is present. It can also be found on swamp, whorled or green milkweed.

Swamp milkweed beetle adult.

The second beetle is the swamp milkweed leaf beetle, Labidomera clivicollis, a leaf-feeding beetle (family Chrysomelidae) found in eastern North America. Both the brightly colored adults and larvae chew on the foliage of milkweeds, primarily swamp milkweed, although they have been recorded on common milkweed, butterflyweed (A. tuberosa), and a few other plants. The dome-shaped adults are fairly conspicuous with a black head and pronotum, yellow to orange elytra with variable black to dark blue patterning, and metallic blue legs. In early summer female beetles lay up to 300 elongate bright orange eggs in batches of 30-60 on the undersides of the leaves.

Swamp milkweed beetle larva. Photo by Jason on bugguide.net.

The plump grey to orange larvae with a row of black spots along the side (similar in shape and size to Colorado potato beetle) go through four instars as they eat leaf tissue until late summer. Just like the longhorn beetle, both the larvae and adults of the milkweed leaf beetle cut leaf veins prior to feeding to reduce the sticky latex in their feeding sites. The mature larvae drop to the ground and pupate in the soil. The adults emerge in the fall to feed for a while before overwintering amid debris or in the soil. In the south there can be two generations per year.  If populations are too high, the eggs or larvae can be wiped off the plants.

The bright yellow aphids with black legs and cornicles found on milkweed plants are an introduced species, the oleander aphid, Aphis nerii, from the Mediterranean region, where oleander is native. This cosmopolitan pest is now found throughout much of North America, where they use milkweeds and some other ornamental plants in the families Apocynaceae and Asclepiadaceae as hosts. The aphids survive in the southern part of the continent, and every year winged females are blown northward on the prevailing winds in the spring. The parthenogenetic females (producing young without mating) give birth to live, wingless, young females to quickly build up populations. They occur in large clusters on new shoots, stems, buds, and leaves. The aphids continue to produce new, often overlapping generations until resources become limiting and they begin to produce winged forms that can disperse to new plants.

Oleander aphids infest many milkweed species including common (L) and tropical (LC), forming large colonies (C) of bright yellow aphids with black cornicles and legs (RC) that attract many natural enemies (R).

Aphids suck sap from the plant tissues, and if populations are high, can stress plants and kill small or newly planted plants. Heavily infested terminals can be stunted or deformed, and black sooty mold grows on the large amounts of sticky honeydew produced by the aphids. If necessary, aphid colonies can be dislodged with a strong spray of water, or can be treated with insecticidal soap, neem oil, or synthetic insecticides labeled for control of aphids, however these actions could also affect small monarch caterpillars.

Many natural enemies, including lady beetle larvae, commonly feed on aphids.

Many natural enemies including lady beetles, syrphid fly larvae, and lacewings feed on aphids and along with parasitoid wasps may provide sufficient control. The parasitoid wasp Lysiphlebus testaceipes lays its eggs singly inside the aphids, where their larvae develop and cause the aphid body to become hard and swollen and a tan or light brown color. A new adult wasp then emerges from the “mummy” that remains stuck on the plant by the embedded mouthparts. These wasps and the common insect predators are not affected by the cardiac glycosides which are sequestered from the milkweed plants by the aphids and are incorporated into the defensive chemicals secreted from the cornicles, but they do deter bird predators.

The related, but less common, pale yellow milkweed aphid, Aphis asclepiadis, occurs on the undersides of milkweed leaves and are generally tended by ants.

– Susan Mahr, University of Wisconsin – Madison


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Additional Information

  • Milkweed bugs – on the Missouri Botanic Garden’s Kemper Center for Home Gardening website
  • Milkweeds: Not Just for Monarchs – an article in the Spring 2011 Wings. Essays on Invertebrate Conservation publication on the Xerces Society website

83 comments

  1. Wow what a lot of information about the various insects that feed on different parts of the milkweed plant. I am involved with a public pollinator garden each summer and so we attempt to grow lots of common & swamp milkweed. As we have tended to the garden, we have seen various bugs, beetles and aphids on the plants and have made an effort to pick off the bugs as we can. It was interesting to learn that some are more harmful to the plants than others and to learn what the different ones look like. I also found it interesting that the large milkweed bug can not winter over in in the roots in WI but each year re-invades from the south, whereas the small milkweed bug can overwinter in the ground as an adult. We have definitely noticed that the monarch caterpillars prefer the young shoots to the older growth.

  2. The one fact I thought was very interesting was that the milkweed tussock caterpillar or milkweed tiger moth, produce ultrasonic clicks from their tymbal organs which bats quickly learn is associated with a noxious mouthful and then avoid the moth as prey.

  3. Very interesting article. Did not know so many other species relied on this important plant.
    I’ve seen the tussock moth near my milkweed but did not know its name. I can’t wait until next year’s milkweed plants arrive so I can look for the species mentioned in this article.
    Will also wear gloves when I am in contact with this plant and when I harvest the seeds.

  4. I new milkweed was important for monarchs, but did not realize there were so many other insects that relied on it to live. It is a very important plant. I also did not know that milkweed sap was a toxin. It is interesting that some of the insects have evolved to eat it without being affected by it. Do you know how many plants are needed to support monarch butterflies?

  5. We are working to have a significant increase in our milkweed plants. It was helpful to know that we should remove the stalk etc. in the fall to help decrease possible bug spread.

  6. The evolved relationship between the milkweed tussock moth and bats is fascinating – that the moth evolved to produce a defensive clicking sound which the bats associate with the milkweed toxins. And I think my red milkweed did get attacked by the oleander aphids this summer. I’ll have to watch again next year, if they come back, to see if I can identify them.

  7. This is a very, very informative article and will help me and others identify the other organisms found on our milkweed patches. It was most helpful to me to have the life stage pictures of the Milkweed Tussock Moth posted. I have seen the fuzzy, white clusters of eggs but never knew what they were! I do now! Thanks!

  8. Thank you for writing this article. I had absolutely no idea that milkweed supported any insects other than monarchs. I have always had a few milkweed plants around the yard however this year I made more of an effort to keep them growing. I was so excited when I saw a half dozen or so monarchs in one flower bed. Now knowing there are other insects that will benefit from these plants I have even more reason to make room for milkweed in my gardens.

  9. Very interesting article going into detail all the types of bugs, caterpillars, etc that truly rely on the milkweed for their food source. When mowing the lawn I sometimes mow them down by accident. I will be sure to try and avoid the milkweed at all cost. You never know what is living on it! I found it also interesting that bats know which poisonous bugs to avoid by sound! Read for edu credit.

  10. I have seen these in my garden and did not know what they were. Interesting article!

  11. I learned so much from this article. I didn’t know much about milkweed and this article provided interesting and informative facts. I was particularly interested in how insects develop a warning mechanism to advertise their toxicity. The information on the milkweed bugs and all of the photos were very helpful.

  12. We have milkweed growing by the kitchen window and out in the garden. There must of been “hundreds” of the milkweed tussock caterpillars feasting on the milkweed. I was afraid our monarchs were going to starve. Glad to hear that the moths and monarchs eat different parts of the plant. Too bad our ‘little brown bats” in the barn won’t eat them.

  13. I have noticed almost all of these on the milkweed in my garden. Glad to know they “belong” there

  14. Last summer I discovered the large milkweed bug on common milkweed on my property. This article is excellent in noting differences in characteristics of the various milkweed bugs. I also was not aware of their ability to cut through the veins of the milkweed leaves to release the toxic fluid. Amazing adaptations. Susan are you the one taking all these amazing photographs. Thanks.

  15. I really had no idea there were so many bugs who enjoyed milkweed and happy to read that they do little damage. I’ll definitely pay closer attention to the plants in my yard. Thanks!

  16. I found it interesting to find the insects attracted to milkweed have color warning markings.
    Monarchs feeding on the young leaves was new to me.
    My first thought when I saw the milkweed bug was how much it looked like a boxelder bug. When I lived in the Port Washington area we had a very lot of boxelder bugs.
    I never thought much about it, but it makes perfect sense that different bugs will feed on different parts of the plants.
    As a side note it might be nice to see the different kinds of milkweed plants and ones that the monarch specifically feed on in the article too. I know of the common milkweed,( I used to consider a weed) a swamp milkweed and butterfly plant.
    Thanks for the article.

  17. Terrific article about the diversity of common milkweed! Amazing how so many insects can share the same host… even though lady beetles might spend some of their time EATING the aphid visitors. Appreciate learning the differences in appearance of the common boxelder bug vs. milkweed bug. Also appreciate learning about the true bugs which cause minimal damage to milkweed plants. Great photo depicting the “four” eyes of a red milkweed beetle. Nicely done.

  18. Not only was the main article interesting, but so was the companion article from CA. We have a lot of milkweed around Wind Point, especially the ponds at Wind Meadows and behind Prairie School, and it is interesting to see all the different insects that live off the plant. Let’s keep planting milkweed wherever possible!

  19. This was a great article! I had seen dozens of the tussock moth third instars on my milkweed. No idea what it was. I also did not know that the milkweed was poisonous to most insects and that those that are able to eat on the milkweed, like the moths and the beetles were highly colored for that very reason.

    The instars ate around all the veins and I was worried there would be nothing left for the monarch caterpillars. Nice to read that monarch caterpillars prefer the baby leaves to the mature leaves. We had some great numbers of monarchs this year despite all the instars!

    Thanks for this!

  20. It’s interesting how the different insects utilize different parts of the milkweed for food.

  21. Very interesting article. I will now be paying more attention to the milk weed plants in my yard and area to discover some of these insects.

  22. I have lots of naturally growing common milkweed on my land and do attract lots of monarchs. I had never read much about milkweed and found this article very interesting. I look forward to observing more life on the plants.

  23. It’s interesting that the insects attracted to milkweed have black and orange or red colorations.
    I see how well milkweed seeds itself, despite the many types of insects it nourishes.
    I worked to get our city to take milkweed off the unpermitted weed list last year,
    along with other beneficial plants such as yarrow, daisy, black eyed susan.

  24. I often see the milkweed beetles, but rarely see the tussock moth larva, although from now on, I will be checking more closely. I didn’t know that both actually eat milkweed the same as monarchs. A very good in-depth article.

  25. This is a very informative article. I remember seeing common milkweed growing on our farm as I was growing up. I had no idea the plants had anything to do with Monarch butterflies. I’ve been adding butterfly weed to my gardens for about three years and I planted several swamp milkweed plants (that I bought at the MAMGA plant sale) the past couple of years. This summer I was rewarded for my efforts by having quite a number of Monarch butterflies in my yard. They are such a joy to watch as they flutter around the yard! I also noticed a large showing of the milkweed bug. I knew they were not boxelder bugs because of their coloring. I “looked them up” in my gardening materials and found them not be harmful. I am happy to see that so many people are interested in the Monarchs and hopefully we can increase their population over the years.

  26. I love seeing Monarchs in my garden. I have been attracting them with Mexican Sunflowers. With future plantings, I plan to include Milkweed. Didn’t know about the other insects that like to feed on Milkweed. They have such beautiful bright colors. Good article!

  27. Interesting that so many things can eat the milkweed even with its toxicity. There has been a large effort to plant milkweed along the Lakewalk in Duluth as well as other pollinators both for bees and monarchs. I will be checking them on my walk for any evidence of these various insects.
    Also curious about problems with dogs as there are many folks that walk their animals there.

  28. Please advise about what seems like an infestation of milkweed beetles and flies on our plants….have not seen many monarch catipillars…maybe 3 this whole year…is it because of all these milkweed nymphs? They’ve even spread to the yellow tickseed plant

  29. We are growing more & more milkweed around our area in northern Wisconsin! So good to see! I’ve seen more monarchs this summer than in many years! Hope their numbers continue to climb. I didn’t know that some milkweed specialists eat around the toxic sap to avoid the effects!!

  30. Article read for CE credit. I have purposely been leaving the common milkweed in my landscape to help feed the monarch butterfly population. Have noticed the various beetles and particularly the milkweed tussock moth caterpillars over the years on the plants. Good to know more about them now.

  31. A very informative article! We are careful to work around milkweed growing on our property and have seen much more because of our efforts. We want to provide more food for the Monarchs but I didn’t realize how many other insects also feed on this plant.

  32. Because of our attention to preserving the milkweed growing on our property we are seeing the spread milkweed. We are interested in attracting the Monarch Butterflies. I did not realize the number of other insects that feed on the milkweed. Also, we have boxelder trees and didn’t realize the milkweed bugs were similar in appearance. Very informative article!

  33. Read article for CE hours. I’ve seen beetles, insects, tussock moth caterpillars and aphids on my milkweed. Knowing that the small milkweed bug sometimes feeds on small monarch caterpillars will keep me more watchful in the garden. I’ve seen more monarchs this year in my yard than in years past.

  34. Thanks for the information. It is helpful to know which insects are fpund on milkweed and how to expect them to behave.

  35. This article pretty much sums up what other organisms I’ve see on my milkweed patches over the years. I have common milkweed, swamp milkweed, and rose milkweed in my gardens at home. I also have established a monarch way station at a school (2006) and an currently managing another one (2008). The co-evolution of milkweed, monarchs and the other insects that live in milkweed patches is absolutely fascinating. I’ve been raising monarchs for 15 years and speak to school children and community groups about the conservation of this iconic insect. It is very helpful to have knowledge of the “other” bugs one might encounter on milkweed. Tagging season is here! Lots of comments here, few (if any) I noted about tagging. This is the fourth year I’ve tagged. I had two tag recoveries last year- both found in Mexico! I hope to tag more this year than I did last. It’s been a banner year for finding eggs and caterpillars in my home gardens. Thanks for a helpful article.

  36. It was amazing to me xo many diffefent catippars znd beetles also use the milkweed plant for food and to house their eggs. D id not know sap was so poisonous, yet used by many as food source. Would really consider planting milkweed to watch the many visiters.

  37. This is my 1st year to have milk weed in my garden. It’s inside of a fenced area where our 2 dogs have free run. I was unaware of the toxic aspect of milk weed and am wondering if I should be concerned for my dogs?

  38. I was fascinated with the beautiful coloration of the milkweed beetles. It seems that this one plant has so many predators but still does well. Looking forward to putting a few of these in my butterfly garden next season.

  39. Great article. I have been raising monarchs for about 15 years now and have always been interested in learning more about these other bugs I see on the milkweed but didn’t know what they were and never really looked them up. Great information on them!

  40. As an organic gardener I always let nature take it’s course when it comes to insects and plants. After reading this and learning that the small milkweed bug may be why my monarch caterpillars are disappearing I may have to intervene! Next year I will capture and raise my monarch caterpillars to give them a helping hand.
    I have also cut back my milkweed by 1/3 to encourage new young growth for monarch caterpillars.

  41. Good to know all the milkweeds bugs there are. I have milkweed in my yard for the first time this year. Now I will have a bit more knowledge about what is invading.

  42. Each year, as larger amounts of volunteer milkweed plants become established in our perennial flower beds, the number of monarchs have noticeably increased. Reading these very informative articles about milkweed plants and learning of the vast community of insects, beetles and bugs that also are part of a complex community milkweed plants support, I have gained new insight into the true value of this native plant. Truly enjoyed the Spring 2011 Xerces Society article which truly summed up what I have just learned, ” Milkweeds support a diverse community of insects that visit to drink nectar or feed on the plant itself – or on the other visitors.” Will be looking much closer at the milkweed in my own garden to see how many additional visitors are actually there. Who knew? Wow!

  43. Learned so much! Did not realize that the cardiac glycoside (white sap) was so poisonous but the flowers & nectar are not. Which is why many bees, flies & butterflies can feed on them. Pretty interesting that the tussock moth makes an ultrasonic click with it’s tympanic organ to ward off bats.

  44. I was surprised to see the adult small milkweed bug resembles the box elder beetle, I am going to have to take a closer look next time. I will watch for milkweed caterpillars, bugs, beetles and aphids, never knew so much were on the milkweed plant!

  45. It is amazing how one plant can support so many predators and survive. Very interesting how the predators know how or where to feed so they do not get the poisonous sap. Balances of nature are truly fascinating to study.

  46. I’ve seen many of these critters on my milkweed. This is the first year I have had the mold on mine… we had a huge aphid population followed by a large lady bug population.

  47. I will definitely be on the lookout for my milkweed caterpillars, bugs, beetles and aphids. I have seen many of the aposematic insects in my yard and now know more about them. I do have many monarchs that cruise through my newly planted butterfly garden courtesy of the Master Gardener plant sale. Thanks for the great article which helps to give a new appreciation for insects.

  48. I found it interesting that the small milkweed bug that feeds primarily on seeds will sometimes feed on monarch butterfly caterpillars or other insects trapped in milkweed flowers.

  49. As a retired RN, I find it fascinating that so many plants have medicinal properties. Cardiac glycosides are a class of organic compounds that increase the output force of the heart and decrease its rate of contractions. Their beneficial medical uses are as treatments for congestive heart failure and cardiac arrhythmias. Relative toxicity prevents them from being widely used. The pictures were very helpful in the identification of all the visitors to
    the Milkweed plant.

  50. I have not observed milkweed tussock caterpillars on the milkweed in my yard and did not know that other caterpillars would feed on milkweed in addition to monarchs. I have seen the milkweed bugs on my milkweed and mistook the nymphs for aphids because I did not look closely before reading this article and realizing that they could be something else. I also believe that my milkweed was infected with at least one of the aphids described in the article. I am glad to have a little more information about the various infestations my milkweed suffered this year.

  51. Very interesting and helpful article. I have seen a few monarchs in my yard this year — the first time in years. I will be watching for these other insects also. I do not have milkweed planted yet but am planning to asdy some. In the meantime I am on the lookout in my neighborhood for where these insects are currently finding food.

  52. I found it interesting that tussock moths make a sound to warn away bats. I also discovered what the orange aphids that have invaded my milkweed patch are. Thanks

  53. I live next to a prairie garden/field and we’ve seen a number of bugs we thought were box elder bugs this year. The prairie used to be farmed up until a couple of years ago and whenever they planted soybeans, we’d be infected with massive numbers of box elder bugs. Good to know what they really are. Very interesting article. I walk through a wildlife management area quite often and will be on the lookout for more of these bugs.

  54. Early this spring I found several small Monarch butterfly caterpillars on my milkweed plans. they were only about an inch in length. I watched the plants to see if they would continue to eat the leaves and grow larger, but they disappeared. I continued to check the underside of the leaves for larva but never found any. No signs of milkweed insects, or longhorn beetles or the milkweed tiger moth. Based on the illustrations in the article I would have remembered any of those. Several Monarch butterflies circled the plants but didn’t land. This is the first year I’ve had milkweed plants in the garden.

  55. I didn’t know there were so many types of milkweed bugs and beetles- I thought they were different stages of the same insect. Interesting that the yellow aphids I see come from insects that are carried on the wind and that these bugs are generally wingless but can develop wings if they are overcrowded. Nature is amazing!

  56. I had no idea about the milk weed bug. My friends and I actually just took photos of them on Rock Island. I recently found monarch caterpillar on my butterfly weed too!

  57. I find it amazing that so many of these milkweed insects have yellow and orange on them to help distinguish them, making predators aware of their potential toxicity. I grew a lot of ornamental Asclepias in my community garden plot this year and was rewarded to see many monarch caterpillars. I’ll do it again next year and keep a closer eye out for more of these insects.

  58. Love that the color of Monarchs, orange and black, are used as an advantage/survival tactic for so many groups.

  59. I had to teach my neighbor about tussuck caterpillars because she thought that they were regular monarch caterpillars.

  60. The oleander aphid ,able to reproduce asexually and in wing/ wingless form depending on resources seems to be from a sci-fi movie. With these abilities what can stop them. Really interesting

  61. Interesting article. I had just learned about the Tussock Moth this summer as a friend was upset that they were eating her milkweed that she planted for the Monarchs. I will be checking out the milkweeds more closely on my walks.

  62. Great information with some good pictures for identification…..headed out to check out my milkweed with this article in hand….thanks

  63. I observed one milkweed bug on one of our milkweed. Since I read milkweed bugs do little damage to milkweeds so control is generally not required I did not spray for them. After reading this article I know now removing old leaves and old stalks in the fall can help eliminate overwintering sites of those milkweed bugs.

  64. It was interesting to learn some of the natural enemies that feed on aphids. And the most interesting information was the activity of the Lysiphlebus testaceipes which lays its eggs singly inside the aphids…seems labor intensive! Thanks, it was an great article.

  65. I have many red, or swamp, milkweed plants in my garden. I do not deadhead in the fall so I have hundreds of volunteer plants that I like to give away as much as possible because it can be readily transplanted unlike common milkweed. I have had more Monarch cats this year than other years so I hope that bodes well for the species. I found it interesting that so many other insects are also living on the milkweed since I thought its toxic sap made it a very limited host. I many orange aphids on my plants. Is this a variation of the yellow aphid or another species?

  66. The wonderful patterns of color on so many of these milkweed loving critters are so enjoyable to look at. What a great variety! And on the background of the large leaves of the milkweed, they are easy to spot. Just today I found a monarch caterpillar at our MG project. As more and more people are learning of the value of milkweed, more and more get to appreciate and identify all these great “bugs”.

  67. The Tussock caterpillars are noticeable on milkweed just about everywhere, it’s amazing how much of a leaf can be devoured in a short amount of time. The milkweed bugs seem to be more common the last couple years. Interesting information throughout the article.

  68. I do not have many Tussock moth caterpillars as of now. I do have a lot of little orange eggs, laid in groups. I am bringing Monarch eggs and caterpillars in the house to raise and release. I just started this. It is a very interesting new hobby!

  69. I don’t have any milkweed on my property, however, I have a Master Gardener friend who does. I’m going to observe the plants and see if I can locate any of the beetles mentioned above, especially the Red Milkweed Beetle since it’s the most common.

  70. This article will help me share information about these insects we always find on milkweeds during summer school with my “Cabin Kids”.

  71. This summer we had volunteers dressed as bumblebees in our CVMGA pollinator garden at the Northern Wisconsin State fairgrounds. One lady complained that monarch caterpillars were massing on her milkweeds. She showed us a picture of tussock moth larva, and we showed her what a real monarch caterpillar looked like since we had a few on our milkweeds. We also miss-identified milkweed bugs and their larvae as boxelder bugs last year. Thanks for the article. As more gardeners are letting milkweeds grow, we are getting more questions about other critters who are occupying them.

  72. I had many of the tussock moth caterpillars this year and did not know what they were until reading this article. I left them where they were since I assumed they are considered a pollinator as were the monarchs that shared the milkweed with them.

  73. I am also raising monarchs so far I have released 97 butterflies, today I released 15 butterflies. The article was very interesting I found my first swamp milkweed beetle this summer I didn’t know what it was for sure untill I read this article. I have aover 250 cats right now and a few eggs. Eggs are getting harder to find, plenty of butterflies but few eggs. This week is Crawford County Fair and we are featuring Monarchs, I have eggs, cats of every size and crystalist and maybe a butterfly or two to show. Two of our MGVs reworked a flower bed at our fair grounds and have registered it as a Monarch Way Station so it ties in with our booth. I have copied this article to use at the fair, it will be very helpful in answering questions. Thank you for your great work.

  74. Great article. I am raising over 300 monarch caterpillars and the information from this article is very beneficial. I have seen many of these insects when hunting for Monarch eggs.

  75. Interesting . .now I know about the yellow aphids on my swamp milkweed

  76. When I first observed the milkweed bugs, I thought they would be dangerous to the monarch eggs and caterpillars so I flicked them off of the plant. By this article, I learned that there are many bugs that feed on the milkweed plants. At first, I did think that they were boxelder bugs. Then I found the different eggs and the strange fuzzy yellow caterpillars, the orangish eggs grouped together and the aphids being eaten by ants.
    It was a whole new world on this one common milkweed plant. A very interesting article as I have housed and raised the Monarch caterpillars to maturity and even tagged them through the Monarch Society.

  77. Hello:

    Interesting article. Have many common milkweed in my yard along with quite a few butterfly weed. Noticed a lot more monarchs hanging around this year compared to last year. Others said the same. Hopefully that a good omen for the future.

  78. We had the milkweed bug here on our Milkweed. I never knew it did not over winter here. Now I have to check out the stripes, triangles and spots to find out exactly which kind they are.

  79. I don’t have a lot of milkweed on my property because I have a lot of shade. But a fellow master gardener has found a shade loving milkweed and started it from seed. She is giving it to me to try and I’m hoping for the best. But the article was quite interesting about the other insects that will eat off of milkweed. I really did think it was only the monarch caterpillars.

  80. I am such a proponent of supporting the Monarchs that I tend to eliminate all of these when I see them, bopping them off the milkweed. I think I should be more selective based on what I’ve read and even allow a Tussock caterpillar or two to live. I then chide myself and think: perhaps all of these creatures are little miracles and deserve a chance to survive–but maybe not on my all-too-few milkweeds.

  81. I didn’t know the milkweed bug looked so much like the boxelder bug. I have seen numerous boxelder bugs.

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