Garden Assassins for Hire

July 27, 2010 | By | Comments (15)

One of the many reasons only numb-skulls douse their whole gardens with insecticides nowadays is that we’ve come to realize that many insects help plants by eating bugs that devour plants. Among the coolest of beneficial insects are the aptly-named assassin bugs. These ninjas of the insect world fearlessly stalk, attack, and consume many harmful and annoying pests without you ever knowing they were there.

Take a gander at the drama unfolding below. A milkweed assassin bug, distingusihed by its red-and-black body, has set its sights on a pesky fly. Any guesses how this scene turns out?

Milkweed assbug

Many genera and species of assassin bugs exist in the world. And though some tropical species seek out people, those in the U.S. are entirely beneficial. They range from about 1/2-inch to 1-1/2 inches long, and depending on the species and stage of life, may be green, red, orange, yellow, black, brown, or gray. Narrow heads with very long antennae are trademarks. Assassin bugs are active hunters and target caterpillars, aphids, leafhoppers, beetles, spiders — really, anything they can catch, even prey much larger than themselves. Once they spot a victim, they uncoil their weapon — and what a weapon it is.


It’s a long, jointed proboscis or beak that works like a hypodermic needle. The assassin bug keeps it curved beneath its head when not in use. But when the dinner bell rings, it straightens out the beak and plunges it into its next meal. Toxin paralyzes the victim, while digestive juices turn its insides into goo that the assassin bug sucks out. Mmmm-mmmm, good.


Unlike most insects, assassin bugs produce only one generation a year. So if you wipe them out through indiscriminate spraying, you’re nuking your garden’s own troops. Assassin bugs are harmless to people unless you’re dumb enough to handle one. In that case, you may find yourself on the receiving end of a painful bite. The worst offender in this regard is the largest assassin bug (show below), called the wheel bug. Named for its wheel- or sawblade-shaped crest, it won’t hesitate to bite you too. (Remember the gross scene from “Starship Troopers” where the smart bug shoves its beak into the head of a trooper and sucks out his brain? It’s kinda like that.)

Wheel bug

This morning, I spotted a little juvenile assassin bug (like the green one eating dinner pictured above) on my red coleus, so I took his picture (below) to show you the relative size.

Assassin bug 002

I sometimes spot assassin bugs in the house too, inevitably having hitched a ride on a plant brought in. Each time, I carefully coax them to crawl onto a piece of paper and take them outside to my garden. My plants could use some more assassins. How about yours?

Thanks to Steve, motleypixel, clicksy, and accent on eclectic for the cool pix.


  1. Steve Bender

    They probably just followed the food. When they find your aphids, they’ll be back.

    April 29, 2013 at 2:30 pm
  2. bmh4796

    i’ve had these docile and shy little critters in my garden in great abundance for 6 years. but they have suddenly disappeared 😦

    i did not use pesticides, so i’m puzzled.

    i saw them over the winter, but haven’t seen them since late january. of course, i have an aphid problem now that my little army is gone.

    any theories as to why they may have disappeared?

    April 29, 2013 at 10:03 am
  3. heather harris

    Thank you so much! I’m a newbie and ran inside after seeing one of these on my herb garden to frantically search on the internet to see if i should run out and squash him or leave him be and walah! i found this post!! Thank you thank you!

    June 6, 2012 at 8:56 am
  4. Corey

    Was checking these guys out in my garden today and wondering what they were. Thanks….makes me glad I went organic this year.

    June 9, 2011 at 10:14 pm
  5. Shane from plants for hire

    Cool. I learned something good about assassin bugs today. I enjoyed reading the post as well as the images you took.
    Really nice.
    Good work indeed.

    February 22, 2011 at 1:22 am
  6. Grumpy Gardener aka His Excellency

    There are many types of assassin bugs. The one that transmits the disease is common Latin America, but not here. Neither is the actual parasite that causes the disease.

    August 20, 2010 at 3:31 pm
  7. not so harmless

    Assassin bugs are known to feed from people. They enjoy feeding from the mouth area, earning them the nickname kissing bugs.
    They transmit Chagas disease.

    August 19, 2010 at 6:46 pm
  8. Dave

    Thanks for the pics of these good guys. I’ve seen them in my gardens and now, knowing who they are, I can give them a little more respect.

    July 31, 2010 at 9:17 am
  9. carl wayne

    And it’s UT orange!

    July 29, 2010 at 1:10 pm
  10. Jim Long

    What a great posting about assassin bugs. I get that question alot…’what are those ugly red bugs and should I spray them?” Great information and pix, Grump.

    July 28, 2010 at 5:11 pm
  11. Grumpy Gardener (His Benevolence)

    Geez, Henry, I never noticed that! I just abbreviated the name and wound up with “assbug.” Sounds painful!

    July 28, 2010 at 3:05 pm
  12. Henry H.

    Glad to see some more info on bene. bugs gettin out there. I was just reading an article the other day about parasitic wasps and how several get wiped out through spraying and etc.
    Haven’t come across a wheel bug yet but it looks pretty cool.
    BTW, I was confused at first when my mouse pointer fell on the first picture and a caption popped up that said assbugs…..

    July 27, 2010 at 4:44 pm
  13. UrsulaV

    Assassin bugs are so awesome. We’ve got scads here in the South, and despite a lot of indiscriminate handling of a wheel bug back in the day in an attempt to get a photo because it was so weird and cool-looking, I’ve never been bitten (proof that god looks out for fools and drunkards.) I am always delighted to see them roaming through the garden.

    July 27, 2010 at 3:46 pm
  14. Dave

    We have those orange milkweed assassins all over. They are more than welcome to feast on any other bug they may find! If I could just get them to eat their relatives the squash bugs I’d be happy!

    July 27, 2010 at 3:02 pm
  15. jodi (bloomingwriter)

    I think I love you. Your sardonic wit is delightful. You had me at “only numbskulls douse their whole gardens with insecticides.” The assassin bugs are fascinating. I don’t know if we have them here in Nova Scotia, but I’m a no-spray sort of gardener so nature pretty much straightens out her own issues. Thanks for this post. Brightened my day enormously.

    July 27, 2010 at 10:27 am

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