Tuesday, November 11, 2014

Little Bugs with a Big Bite: Minute Pirate Bugs

Sometimes it seems the tiniest of insects is the biggest nuisance. Mosquitoes come to mind, as well as black flies, and "no-see-ums" or "punkies" (biting midges in the family Ceratopogonidae). One other insect often responsible for surprisingly painful bites is the aptly-named "minute pirate bug." There are about 90 species in the family Anthocoridae found in North America, in 22 genera, but only a few cause us grief.

Insidious Flower Bug biting me in Colorado

The Insidious Flower Bug, Orius insidiosus is, appropriately, the species most likely to get under your skin. Well, on your arm, hand, or neck, where it will likely probe you painfully. At only 2-2.5 millimeters, it is possible to overlook it entirely when trying to pinpoint the source of your irritation. In the right light, however, the little bug appears bright white and black.

Despite dispensing unprovoked bites, Orius insidiosus is actually a highly beneficial bug. It is a predator of many crop pests like very young caterpillars of the corn earworm, plus insect eggs, aphids, whiteflies, thrips, and mites. Consequently, this minute pirate bug is reared commercially and sold to farmers as a biocontrol agent.

It takes only twenty days, on average, for O. insidiosus to go from egg to adult. Females lay two eggs per day, and about thirty during their lifetime. Each ovum is deposited in foliage such that the top of the capsule protrudes above the leaf surface. In about four or five days, the first instar nymph emerges from the egg. During the next two or three weeks, the nymph goes through a total of four more instars before transforming into a fully-winged adult bug. The adults live an additional three or four weeks.

Insidious Flower Bug biting me in Kansas

Adult Insidious Flower Bugs overwinter in leaf litter and probably other debris on the ground. Several generations can be produced annually over the insect's wide geographic range. It occurs east of the Rocky Mountains, plus parts of California, and has been introduced to British Columbia. Because it is available commercially, it has likely spread elsewhere, too.

Adult Anthocoris musculus, Colorado

Another species I have found commonly here in Colorado Springs is Anthocoris musculus. It is a real giant by pirate bug standards, measuring 3.4-4.0 millimeters as an adult. I have found it associated with cottonwood trees, and it is well-known from willows and other deciduous trees and shrubs as well as herbaceous plants.

Nymph of Anthocoris musculus, Colorado

It is potentially an important predator in orchards, and has been observed eating red mites and "eye spotted bud moth" in Nova Scotia (Kelton, 1978). This species ranges throughout most of North America including Alaska and northern Canada.

The next time the pirate bug bites, simply utter "Ar-r-r-r!" and remember their beneficial qualities. After all, they are probably keeping your garden free of other tiny pests.

Adult A. musculus feeding on unknown object, Colorado

Sources: "Minute Pirate Bug aka. Orious insidiosus," Evergreen Growers Supply.
Gibb, Tim. 2006. "Have a thick skin when it comes to Insidious Flower Bugs," Purdue Plant & Pest Diagnostic Laboratory, Purdue University Extension
Hull, L.A. and R.L. Horsburgh. "Minute Pirate Bug, Orius insidiosus (Say)," Mid-Atlantic Orchard Monitoring Guide.
Kelton, Leonard K. 1978. The Anthocoridae of Canada and Alaska. Ottawa: Canada Department of Agriculture. Publication 1639. 106 pp. (PDF).
Slater, J.A. and R.M. Baranowski. 1978. How to Know the True Bugs. Dubuque, Iowa: Wm. C. Brown Company Publishers. 256 pp.

28 comments:

  1. May I ask if you've ever heard of bird mites invading homes and biting humans?

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    1. Yes, I have definitely heard of bird mites invading homes when their normal hosts (birds) leave a nest built on or in a human dwelling. Mites, however, are entirely different than the *insects* discussed in this post.

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  2. I have a tiny winged hemipterid that is biting me, but it doesn't look like the photos here. It is light brown, has a sort of darker brown delta on its thorax, and faint gold and brown striping on its otherwise clear wings. It's tiny, but its bite is very itchy. I'm in East Kansas. Can you help? I'd upload a photo but these comment boxes don't seem to permit it.

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    1. Please try the "Forum" tab at the top of the page. There is an option to upload images with your questions. I'm still betting it is a type of minute pirate bug, but we'll see. Thanks.

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  3. It appears that the picture of the one biting you in Kansas left a little blemish on your skin, as did one that bit me before. My "scar" went away in a few days. Are these insects actually feeding on us? Can they use as sustenance?

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    1. I think it bit me on a freckle....Excellent question. I think a good number of true bugs are just constantly probing to see if the object they are on *is* potential food. That said, I am no expert on this particular group of true bugs.

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  4. Hi I live in Ireland and a tiny beetle bit me on the wrist in the garden - it looked like the minute pirate beetle - but is it possible that they live in Ireland?

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  5. How do I get rid of them, they are a parasite that needs to leave me alone. I can't seem to walk outside without getting attacked by them. Like 50 at a time.... not exaggerating.

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  6. Hello im in southern mexico and there are theese tiny tiny tiny orange bugs that really itch and they seem to be biting me around the arm pit and other warm areas, do you have any idea what theese could be

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  7. I live in the Adirondacks in northern NYS, and until this summer have never encountered these little bugs - at least as I have this year. They're biting something fierce. Is it possible they're undergoing a population boom, or is warmer climate expanding their range?

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  8. How can I get rid of these pirate bugs0

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    1. I never tell anyone how to "get rid of" anything. The whole goal of this blog is to change attitudes like that.

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    2. Unless you are the one who is getting bit up!

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  9. Hey bug Eric, I work in the marijuana industry in Canada and we have thousands of these being released every single day and I'm getting bit like crazy by them is there any harmful effects or can you talk further about the effects to the human skin on the bites of these creatures

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    1. I shared the extent of my knowledge in this post. You will need to consult articles in scientific journals that are related to the use of Orius spp. as biocontrols in agriculture.

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  10. I live in Edinburgh Scotland and I have identified these little pests as the ones the keep biting me on the hands and wrists as I pick raspberries in my garden. It's an extremely painful bite for such a small creature and I seem to react badly to the bite and I'm scratching for days.

    At least I know what hey are now!

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  11. Hi,I live in the UK, I have just been bit by a bug simular to your minute pirate bug. Is it possible to be the same species and if so how can I stop the sting of the bite ? At the moment it's throbbing and rising pretty much straight away after I felt/caught the little bug pierce my skin. How can I help the irratation please?

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    1. While I empathize with your situation, this is not a medical blog and for legal, liability, and ethical reasons I cannot offer medical advice. Thank you for understanding.

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    2. Bug Eric we keep having little black bugs like this bite us but after the bite it feels like little pieces of glass or installation is all over where we just got bit. Do u know if this is what the insidious flower bug bite feels like?

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    3. That is a reasonably accurate description of the average bite reaction. Since each person's immune system is unique, we cannot easily generalize, though.

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  12. Hi Eric! This is so helpful! We have these bugs that seem to be helping our roses. However, it seems they have moved into our house. Do they live inside? Will they lay eggs inside and infest the home? Trying to understand the lifecycle and hope they leave the house with the season. We live in San Francisco.

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    1. These are strictly outdoor bugs and will not "infest" your home. They are sometimes attracted to lights at night, so maybe that is part of the problem. Some years they are more numerous than others, or so I am told.

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  13. Can these live in u

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    1. No, these bugs do not tunnel into your skin. Very few insects are capable of that (Chigoe flea, some bot fly larvae).

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