Lovely Harlequin Bugs Visit My Garden

A pair of juvenile Harlequin Bugs (Murgantia histrionica)
A pair of juvenile Harlequin Bugs (Murgantia histrionica)

I first noticed these beautiful little bugs in my garden four weeks ago. Their fantastic coloring of orange, black and white was hard to miss. I didn’t run to my identification field book right away. I decided it was much more fun to watch these little insects instead.

At first I thought they must be beetles because they were so colorful, but the triangular shaped shield on their backs gave them away. They were bugs, true bugs. In beetles the hard wing coverings form a straight line down the back. True bugs have a triangular shaped piece called a “scutellum”, instead.

These flashy little bugs, only ¼” to ½” long, were only found on the spent broccoli plants I left standing in the vegetable bed. They seemed to be extracting liquid from the broccoli plants. The bugs had the sucking mouthparts, rostrum, that all true bugs have. The bug I was watching unfolded its rostrum from beneath its head and inserted into a broccoli seed pod. You can just see the feeding tube in the photograph above if you look closely.

These bugs live multi-generational with eggs, new hatchlings, various size juveniles and adults, all sipping and living on the same plants. There is no larval stage in their life cycle like butterflies or beetles that have chrysalis or grubs. The newly hatched babies look similar to the adults, just smaller. This is called simple, gradual or incomplete metamorphosis.

So, for weeks early in the morning I would go into my garden and watch the orange and black bugs make their way to their feeding places. They must retreat further down the plants into the cooler darkness of the vegetable bed at night. As the sun rises and the air warms, they travel up the stalks to the tops of the seed pods to warm themselves in the bright sun.

I felt I had learned enough from direct observation, to now flip through the field guides and find out the scientific and English names for these little bugs. Using my National Wildlife Federation Field Guide to Insects and Spiders & Related Species of North America, it didn’t take me long to spot the Harlequin Bugs (Murganita histrionica) on page 129. They are also called Calico or Fire bugs.

No wonder I hadn’t seen these bugs before, they are from the southern half of the United States. Apparently, if the winter is mild (which this past winter was), Harlequin Bugs can be found during spring and summer as far north as New England. Adults hibernate in plant debris and litter to survive the winter.

Harlequin Bugs are common in gardens, fields, and roadsides. They feed on plants in the mustard and caper family. The bugs feeding causes white and yellow blotches on the plant. So, to find these colorful little bugs check broccoli, cauliflower, collards, horseradish, kohlrabi, mustard, radish, turnip, citrus and cherry. These are transported food crops brought to North America. It makes me wonder if these bugs are indigenous or newcomers to this land. It would be useful to know what, if any, indigenous plants these bugs eat.

The female Harlequin Bug lays eggs on the food or host plant, just like female butterflies do. Another example of host plants being important.

Observing these insects before running to consult the field guide made me really look at them. I appreciated their coloring and habits. I think if I had just looked them up in a book, I would have found the answer quickly and felt I knew everything about the bug, without really studying them. The first hand information I learned will stick with me long after the field guide words have been forgotten.

10 comments

  1. They love the flowering plant (i have found) Cleome. The plant makes it’s own seeds fr next spring but with the cold, rain, birds (who I also love) I usually buy packets of Cleome seeds in the Spring at the plant store.
    I too was fascinated watching them mature – thank you for the wonderful picture. This is the first year that I haven’t seen a single one (2020) and I am so disappointed. I don’t know why they are not here – but I miss seeing them. When the plants die – i have managed to keep them alive longer by putting out cabbage all over the middle of the fence where there is a railing. But then I wonder if I’m keeping them above ground and they will be stuck in the cold – – so I stopped that and let nature take its course and hope that they burrow into the ground. Thanks again for your post and lovely pictures – I am in DC.

    • Hi, Nancy – Thanks for contacting me. You won’t keep them from getting ready for the cold season. Like many insects their bodies respond to length of daylight and low temperatures. Certain substances will be made by their bodies as preparation for the cold. The insects can’t ignore that and keep eating. Whatever life cycle stage they overwinter during, they will overwinter when the time comes. If Harlequin bugs overwinter as eggs or larvae, then the adults will die as the autumn season progresses. So, keep feeding them cabbage leaves if you want to. 🙂

  2. These are stunning little bugs. I really appreciate your comprehensive observations and especially like seeing those barrel eggs and hatchlings.

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