Tuesday, January 8, 2013

True Bug Tuesday: Masked Hunter

Note: This is the debut installment of a semi-regular feature I am dubbing “True Bug Tuesday.” It will likely include reposts of previous entries that cover members of the order Hemiptera.

Remember when your parents told you there were no monsters under your bed? Perhaps they were wrong. Have you ever wondered if you were hallucinating when you swore you saw a self-propelled dust bunny crawling across the floor? You might have been perfectly sane. There is a predatory insect that qualifies as both a miniature monster and an animated dust ball, and it is most often encountered indoors rather than outside.

The Masked Hunter, Reduvius personatus, is a member of the assassin bug family Reduviidae. Fortunately, the only thing it “assassinates” is other insects and related invertebrates. The piercing-sucking mouthparts are sleeved inside a short, stout, segmented beak bent under the insect’s “chin” when not in use.

The most remarkable trait of this species is the appearance of the immature stages, called “nymphs.” True bugs in general go through “gradual” metamorphosis, such that the juvenile stages look much like the adults, except that they are smaller, not sexually mature, and lack wings (if the species in question has wings at maturity). This is true of the Masked Hunter, except that the nymphs actively cover themselves in lint, sawdust, and other debris.

Their bodies are covered in short and long trichomes (hairs) connected to glands that produce a sticky substance. Fine particles adhere to the short trichomes close to the body of the insect, while longer trichomes anchor coarser particles in a second layer of camouflage. A “tarsal fan” of dense, long hairs on the foot of each hind leg helps the nymph apply the trash to the trichomes (Weirauch, 2006).

Each time the baby assassin molts (sheds its exoskeleton to grow in the brief interval before the new exoskeleton hardens), it must repeat the self-decorating process. The disguise helps protect it from potential predators, but might also make it appear harmless to its own prey. The Masked Hunter is probably a generalist predator, but it is often found in association with people and/or colonial birds and bats. It is well known for preying on bed bugs and swallow bugs (true bugs in the family Cimicidae). Other prey records include silverfish, booklice, and at least one harvestman (Arachnida: Opiliones).

Masked Hunters go through five instars. An instar is the period between molts. The nymphs are the ones that overwinter, usually in the fifth instar, but in Canada the life cycle may take two years, the nymphs overwintering in the third and fifth instar (Scudder, 1992). During the winter they are in diapauses, ceasing activity until the following spring. The sixth molt produces the adult insect, a dark, winged animal measuring from 15-22 millimeters in length.

Today, the Masked Hunter is found throughout the Northern Hemisphere. It is assumed that it is European in origin and has been transported to other continents through human travel and commerce. While it can be a common species, it is not prolific, and populations are usually small. Few specimens will occupy any given home or other building.

Assassin bugs are able to produce sound by rubbing one body part against another, a phenomenon known as “stridulation.” In this case, the insect rocks its head up and down, rubbing the tip of its beak across a series of transverse ridges on its "chest." The result is a very audible squeaking sound that may startle any other creature that grabs the bug.

The Masked Hunter is found throughout the Northern Hemisphere. It is assumed to be European in origin and has been transported to other continents through human travel and commerce. Most adult specimens of Reduvius personatus are seen in June and July. Look for them at lights at night where they are occasionally attracted by the buffet of potential prey insects. By day, they hide under bark on logs and in other sheltered situations. Be careful, though, Masked Hunters can deliver a painful bite in self-defense.

Sources: Hoffman, Richard L. 2006. “Assassin Bugs of Virginia,” The Insects of Virginia 15: 1-74.
Scudder, G.G.E. 1992. “The distribution and life cycle of Reduvius personatus (L.) (Hemiptera: Reduviidae) in Canada,” J. Entomol. Soc. B.C. 89: 38-42.
Weirauch, Chrstiane. 2006. “Anatomy of Disguise: Camouflaging Structures in Nymphs of Some Reduviidae (Heteroptera),” Am. Mus. Novit. 3542: 1-18.

27 comments:

  1. Thanks!!! Really helped me at school with my invertebrates unit!!!

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  2. I found one of these bugs coming out from under the floorboard in the study. It looked as though it had curly hair all over its body,very cute. I took a photo of the Nymph for my desktop, before releasing it under my garden shed. I'm so glad to find out what it is and its habits on this website as I've never seen anything quite like it before!

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  3. Every aspect of this is absolutely fascinating! I wouldn't mind seeing one of these here at our house, though it might have some cat hair adorning the lint.

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  4. I did once find a masked hunter in my bathroom. I thought it was an adorable little thing -- and I'm not a bug/insect fan in general, with the odd exception like acorn weevils. Upon researching I realized the 'cute and interesting texture' of its body was actually kitty litter!

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    1. GREAT story, Aiesha, thank you for sharing! :-)

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  5. Recently spotted one of these in the living room and released it outside. Hoping this sighting was just a coincidence and he's not actually feasting on bed bugs (we haven't spotted any of those, but now I'm concerned!).

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    1. They *will* feed on other household insects, Rebecka, so I would not be overly worried. Prevention is the key to controlling bed bugs. Please see my "A Bed Bug Primer" post for help with that.

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    2. thanks for your response, I'll take a look!

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    3. You are most welcome, always!

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  6. Had one of these fly into my jacket sleeve and start biting my arm. I now have a bruise like appearance approx. 2-1/2 in dia. Is there a remedy for this?

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    1. I am so sorry! Unfortunately, this is now a medical question that I am not qualified to answer. Do take care and hurry to your physician or the ER if things do not improve or get worse. Everyone's immune system is different.

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  7. Is it possible for thses to be found in clothing n blankets appering as lint balls? I have lint balls all over n I feel like they have little bugs in them ??

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    1. If you leave clothes on the floor, then yes, possibly, though the lint balls would walk around if they were actually Masked Hunters.

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  8. Are these the same as the kissing bug people are freaking out about? I have found one in my basement and didn't get a clear answer online. No bed bugs, other bugs are minimal. Thanks

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    1. These are often confused with "kissing bugs." Both are assassin bugs in the family Reduviidae, but the similarities end there. The Masked Hunter preys only on other insects. They get into our own home now and then, and we don't have many other insects, either, so who knows why. No need to be worried in any event.

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  9. I sat down on my front stoop tonight and felt "watched". I turned to my right and there it was, a six-legged piece of dirt, hahaha. Thank you for this wonderful article. Nice to know "who" was watching me. :)

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  10. I was laying in bed and had one of these bite me on the back of the neck. Yelled at my husband to follow me to the bathroom light to look at it since I didn't feel a bug there. It was on my back, we swatted it off and of course killed it because we had no idea what it was. Then I turned around and there's another one on the wall. It was so hard to find what kind of bug it was since there's not much information on them anywhere. Meanwhile I feel like my neck keeps getting stung by several wasps nonstop. Finally come across this article with plenty of info on these little monsters. Since we do not have bedbugs or many other bugs in the house besides some moths occasionally, I'm wondering do they eat moths and that's why they're in my home? Anyway thanks so much for such an informative article!

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    1. First of all, I am sorry you have had bad experiences with these! Yes, they are willing to eat other insects besides bed bugs. Hard to say why some homes seem to be more attractive to them than others.

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  11. I found one of these crawling near the cat's litter box. Sadly, I mistook it for a tick and squished it between a Kleenex. oops! I'll release the next one outside.

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  12. Hi i have a bug thaf i found on my kitchen work top i have a picture but dont know how to put on here please can some one help me i live in the uk thanks in advance.

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    1. You can try using the forum I have set up (see tab at top of this page). Otherwise, upload the image to the web and furnish a URL link that I can click on to view it. Thank you.

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  13. One found its way on my leg it hurt like hell should I be worried it looks like the adult form

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    1. Reactions to bites vary greatly, mostly due to your personal immune system response. Do monitor the symptoms. They should not get worse. Seek medical attention immediately if you experience profuse sweating, shortness of breath, etc. Also, note that the Black Corsair, Melanolestes picipes, looks almost identical. *That* might be your real villain.

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  14. I just got bit by one of these this morning in my bed!!!!!! it felt like bee stings for 5 min straight. ahhhhhhh so its not poisonous?

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    1. Reactions to bites vary greatly, ostly due to your personal immune system response. The worst bite I ever received was from a *smaller* assassin bug species, so....There is little question that assassin bug saliva has paralytic qualities for subduing prey, so in a sense they do have venom.

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