The Cuckoo Wasp: A Gorgeous Parasite

by on July 01, 2012

 

Cuckoo wasp (Chrysis sp.) on seacliff buckwheat near Santa Barbara.

Photo (c) Alice Abela.

 

 

A cuckoo wasp is one of those remarkable animals that appears for just a few seconds and makes you wonder what the heck you just saw. Fast-moving and no larger than a skinny housefly, these wasps stand out nonetheless: They glow an outrageous iridescent blue-green, as if illuminated from within.

Cuckoo wasps pack a lot of drama into their tiny bodies. Their color is part of the mystery. These wasps are parasites, and like their namesake cuckoo birds, they lay their eggs in the nests of other species (wasps or bees in this case). Since the cuckoo wasps depend on trickery and camouflage to fool their hosts, you might expect them to be drab. Scientists have not figured out whether the bright colors serve any function, and it wasn’t known until 2009 that the color is actually produced by light refracting through open spaces between six layers of cuticle in the wasps’ exoskeletons.

Cuckoo wasps favor warm Mediterranean climates, and California is a center of cuckoo wasp biodiversity in North America. They are most active in dry, open areas between May and August, with adults foraging on flower nectar as they follow favored routes multiple times a day searching for solitary wasps and bees to parasitize.

Each of the 166 cuckoo wasp species in California targets either a specific host or a specific nest structure. Many species target the nests of mud dauber wasps. One such species, Chrysis angolensis, initially traveled to the New World from Africa by parasitizing mud dauber wasps that nested on the wooden beams of sailing ships. Fortunately for the cuckoo wasps, their larvae’s hatching was well-timed to the sailing ships’ slow progress, and these insects are now established around the Bay Area and port cities in the northeastern United States.

Cuckoo wasps might duck their parental responsibilities, but it’s not exactly an easy living. Cuckoo wasps that parasitize ground-nesting bees and wasps must somehow slip their eggs into an underground burrow without being detected. They first find bees and wasps that are in the process of digging burrows and dragging paralyzed prey into their nests as food for their own young. Female cuckoo wasps then hide nearby to watch the burrow and either try to hitch a ride on the paralyzed prey as it’s being dragged into the burrow or else wait until the host flies off and then slip inside.

Cuckoo wasps can curl up like armadillos, a useful defense when they get caught invading another insect’s nest. Photo (c) John Hallmen.

Despite their caution, cuckoo wasps are frequently caught in the act of sneaking in, but their oddly pitted exoskele-tons protect them from the stings and bites of their hosts. The undersurface of the cuckoo wasp’s midsection is cupped so the wasp can tuck in its legs and curl into a tight ball (like a sowbug or armadillo) to protect its body. Host bees or wasps then have no other option but to grab the balled-up cuckoo wasp in their jaws and carry it outside the burrow to evict it. The unharmed cuckoo wasp simply turns around and tries to get into the burrow again.

Once the female cuckoo wasp succeeds in leaving its eggs in a burrow, the larvae have two survival strategies. Some larvae eat both the host’s larvae and its food items right away; others wait until the host larva eats its food supply and reaches full size, and then they eat the host larva. The first option requires the cuckoo wasp to eat several different kinds of food before it can pupate, while the second strategy lets the host larva do all the work, converting food stores into one juicy meal.

Recent studies suggest that while these brilliantly colored wasps are easily seen and recognized outside the burrow, they are “invisible” in the darkness of the burrow because they camouflage themselves by simulating the smell of their hosts.

So what’s the point of all that color? It may have no function at all. The scientists who reported on the source of the color speculate that the spacing between exoskeleton layers appears to protect the wasp from bites and stings or serve as a thermal buffer from the heat of the ground. And the resulting color may be just an incidental tip-off that a tiny bit of insect intrigue is buzzing by us on the trail.

Nature news junkie? Get our weekly news digest!

 

51 comments:

Debbie DeLoatch on April 15th, 2013 at 11:27 am

I saw two of these cuckoo wasps in my back yard in northeastern NC. I was pulling dry twigs from snapdragon flowers planted in an old mule trough. I would like to know if they sting like a regular wasp.

David Lukas on April 15th, 2013 at 5:57 pm

Great question! It seems that these wasps have stingers but the stingers are greatly reduced so the answer is that they can sting but not with the impact of a regular wasp. More people report being bitten by cuckoo wasps than stung by them.

Bob on June 21st, 2013 at 4:39 pm

Very small iridescent green wasp today late afternoon in Athens, Pa., USA.
Must be the Cuckoo Wasp.

Jean S on June 23rd, 2013 at 7:40 pm

I just had about 5 of these in the lockbox for my swimming pool cover. They were there for about a week.

Jean S on June 23rd, 2013 at 7:40 pm

OH… sorry… I am in Hillsboro, Oregon

kim h on June 28th, 2013 at 3:05 pm

I just killed one from my kitchen cabinet… I didnt know what it was!

Taryn on June 29th, 2013 at 2:28 pm

Saw one of these guys on my floral wreath on my front door yesterday afternoon. I had no idea what it was. I’m in Vancouver, WA.

christina on July 3rd, 2013 at 5:41 pm

I just had my son come running to me sayin “mom look at this bug!” I was like wtf is that and on closer inspection saw that it had a stinger lol luckily neither of us was stung and my son man handled it for a good 5 min before he gave it to me so they must not be as ill tempered as their relatives. Really pretty little thing tho glad I got to see one. I released it on my lillies so maybe it’ll find a nice juicy wasp nest somewhere near by an eat em lol.

christina on July 3rd, 2013 at 5:41 pm

Oh yea forgot to say I’m in Portland oregon

Noelle on July 17th, 2013 at 8:18 am

I’m outside of Richmond, Va. I just found, and killed, one along with 2 yellowjackets, in my front window. There’s a yellowjackets next in the stoop under my front door that no one has been able to fully take care of… I wonder if she was laying eggs in their nest? very very beautiful blue!

andrea on August 27th, 2013 at 7:21 am

Just had one in my bedroom, my cat was trying to get a hold of it. I seen it was curled up and thought she had killed it till I seen it climbing up wall and I killed it. I didn’t know what it was till now. Edison, New Jersey

Erin on August 29th, 2013 at 6:50 am

Found one in the house last week. Caught it and let it go outside. I’m near Columbus, Ohio.

David Lukas on August 30th, 2013 at 9:31 am

I’ve observed cuckoo wasps in many different places in my life, but I’m really enjoying everyone’s comments because I had no idea that these lovely little insects were so widespread. They definitely catch your eye don’t they!

Kaylyn Edwards on August 31st, 2013 at 10:06 am

These wasps have been hanging around my house for a month or so now. I see them all the time. The first time I tried to kill one I was sitting at the table and hit it with a rolled up magazine. It curled up into a ball and I thought it was dead. A few minutes later it popped up and started crawling around! Kinda scared me so I smashed it with my coffee cup, that’s when I noticed the stinger!

Kaylyn Edwards on August 31st, 2013 at 10:06 am

PS — I’m in Kimbolton (southeastern) Ohio.

Shannon on September 6th, 2013 at 7:23 am

My son found a dead one in the window sill and thought it was a fly. It looked too pretty to be a plain old house fly! I’ve never seen one until now so, I had to do some research. With help from Facebook friends, finally figured it out. -in Green Bay, WI

Dr Anisetti Thammayya on September 19th, 2013 at 6:51 am

I was inquisitive when I saw a blue green wasp doing some thing on the mud nest of a yellow wasp. It was touching its hind portion on the mud nest when the builder of the nest yellow wasp flew there but driven away by the invader wasp. Now I understand that it is a cuckoo wasp which is parasitic. I photographed it with my camera. I saw this in our house in Kakinada, Andhra Pradesh, India. The insect is not common to this place. I thank David Lukas for his valuable note on the wasp which helped me to identify. We see wonders in our surroundings if we care to explore.

Vicky on October 17th, 2013 at 2:10 am

Seen one in Madrid, Spain this morning! but the poor guy was dead…took some photos of it.

Vicky on October 17th, 2013 at 2:15 am

By the way…why do so many people just kill these little guys? open the window and let them go..or capture them with a glass and throw them out. No need to be so mean to them! they are just living as you are.

David Lukas on October 17th, 2013 at 11:54 am

I can’t imagine killing one. Even if someone was afraid of insects I think they would be captivated by the incredible sparkling colors of these delightful little wasps!

Gretchen Gillfillan on March 26th, 2014 at 2:55 pm

Yesterday on an insect program, at Tilden, a kindergartener captured a Cuckoo Wasp. With our hand lens we could see its AMAZING colors. Incredible!!!!! to see your name, David, on this site.
Love,Gretchen

Jo on April 7th, 2014 at 1:14 pm

Watched two of these in my garden yesterday in the Bay Area, CA. they were amazingly beautiful, a kind of jade iridescence in full sun and deep blue in shade. I shouldn’t have considered killing such amazing creatures even if they were harmful to my edible seedlings or myself ( which they are not). I read that they do not/ cannot sting. They females sting has been converted into a tube for laying eggs.

RZ on June 16th, 2014 at 9:38 pm

I plan to kill everyone I find again. I got bit/stung by one trying to save the “pretty bug” from our swimming pool. It landed on my toe, after the tidal wave of water subsided it stung me. My toe was swollen for a week, thank goodness for Benadryl. Pretty bug, but, I’m glad I figured out what it was before my kids did. I wish it had just hung out in the wasps nest. We’d all be happier!

s. smith on June 23rd, 2014 at 8:19 pm

I saw two of them while relaxing on my porch. One landed on my knee and stung me. It left a mosquito-bite looking welt. I’m in the northwest corner of SOUTH Carolina.

Mary on June 30th, 2014 at 3:20 pm

Just spotted 3 of these wasps on my house in Duluth, MN. They really get around!

David Lukas on June 30th, 2014 at 4:59 pm

I’m curious about the reports of “stings” because the definitive description of this family of wasps says that their stingers are “quite reduced and essentially non-functional” which probably means they can’t sting or that their sting is quite weak. I wonder whether even a small sting is enough to affect folks who are allergic to bee stings? But still, there’s no reason to kill one of these unusual wasps. They are solitary and don’t pose a risk of setting up a nest or regularly stinging anyone.

Chris Acosta on July 10th, 2014 at 5:05 pm

found one of these hanging out on the outside of my car window when I was going back to work after lunch. I’m in Ga on the Chattahoochee river.. it was very pretty and it let me get pretty close to check it out without flying away. I figured it was some kind of wasp but I’ve never seen one of these before.

Andrea on July 11th, 2014 at 9:32 pm

My son found one on his window sill in Poplar, WI. Weird type of bee, thanks for the info here, I had no clue what it was. It definitely had a stinger and I didn’t want my children to be bothered by it.

Matt on July 13th, 2014 at 5:12 pm

My wife found one of these while doing laundry in our basement in the Philly suburbs.

Kim on July 14th, 2014 at 3:14 pm

I just found one dead in my house in Duluth, Mn.

Christine on July 17th, 2014 at 7:12 pm

Found one in my office. Didn’t know what it was. I was holding it in my hand. Beautiful bug. I had no idea it was a wasp and I’m allergic to bees. Good thing I didn’t get stung. Fairfax, Virginia.

Deborah on July 20th, 2014 at 1:17 pm

I just captured one in my house and had to take some pictures of it before I released outside. It’s a beautiful bug. Virginia Beach, Va. Is this bug common on the east coast?

Erica on July 23rd, 2014 at 10:42 pm

As I was getting into bed tonight I felt a weird pinch/bite sensation on my chest underneath my shirt. I jumped up and switched on the light and there was one in my bed. I have 2 small whelps on my chest where it stung or bit me. Definitely not as bad as a regular bee or wasp sting but is painful still.
From Crockett, Texas

Phillip on July 27th, 2014 at 5:11 pm

Just saw one today, captured it, showed it to my boys, (6 (today! :) ) and 2). Fun Birthday surprise for him, and neat to see it. We let it go back outside. – West Point, UT

Cathryn May on July 28th, 2014 at 9:03 am

Just found a live one this morning on a window screen. Beautiful colors and when I touched it, it curled up like a ball. I was so fascinated that I’ve spent 3 hours on the net for info. on it.!! While going back and forth to the window screen to look at it further, I noticed a dead one in the window track… along with several dead wasp/bees. I agree with David Lucas’s observations and comments. I am an epipen carrier for bee stings, but I don’t know that it would cause me much harm. I think that “RZ’s” comments about a swollen toe for a week, may have happened because he/she is sensitive or allergic to bee stings. BTW I live near Gravenhurst Ont. Canada, and I let the little guy go > outside. I hope I see another one someday !!

cindy arredondo on July 29th, 2014 at 11:19 pm

Found one on the window yesterday. Thought it was a very uncommon color for any type of bug. Had no idea it was any type of wasp. Thank you for this informative article. From Los Angeles ca

Johanne Schultz on August 4th, 2014 at 4:46 am

Saw one of those last week in Jacksonville, Florida.

Brian on August 10th, 2014 at 5:13 pm

I just had my very first in counter with these marvelous insects. I was able to catch it alive. As a neuroscientist, I am very curious as to learning more about this. I enjoyed reading all the comments. I will post more in the near future.

Brian on August 10th, 2014 at 5:14 pm

Forgot to mention. I reside in Texas. I have not heard of many reporting of these parasites here and it is amazing to see how wide spread they are.

Kathie on August 25th, 2014 at 6:44 am

Found one of these walking around on my hydrangea leaves last week. I had never seen one. My brother in law told me what it was. I reside in Massachusetts

Sonja on August 28th, 2014 at 10:39 am

Caught one stuck between window and blinds.Flushed it down toilet saw the stinger and thought it would sting.I live ib Avenel N.J.

David Lukas on August 29th, 2014 at 9:45 am

I know it’s an instinctive reaction to kill wasps, bees, and flies but most of them are native species that play unique and vital roles in your local habitats. In fact many species are struggling to stay alive in the face of habitat loss and pesticides and the last thing an insect wants is to be trapped behind a transparent window with no way to escape. It might go against our instincts but these insects need us to help them out.

amy on September 12th, 2014 at 6:59 pm

I live in Humboldt County California. I got bit or stung 3 times by one. I was bending over in my garden and felt a couple sharp stings. I thought it was a earwig. I Opened up my shirt and that little thing in there. Its 4 days later and I have two swollen areas where I got bit or stung. Its still really painful. I am putting cortisone 10 on it.
I still see them every day moving around fast in my raised garden beds. Probably getting water off of the leaves of my brussel sprouts. Other wasps do that all summer long.

Maree on September 12th, 2014 at 10:24 pm

I’ve had a “bug” in a jar for 12 years now. My dog was inquisitive about a bug between my curtains and the door. Not wanting him to get hurt, I sprayed it and put it into a jar. It went from a bright green in colour then turned into a gorgeous deep purple in colour and the sting protruded upon its death, reaching about 1cm in length. It took me many years to find out what it was and I FINALLY know that it is a Cuckoo Wasp. To this day, I still have it in the jar and will always keep it.

Maree on September 12th, 2014 at 10:25 pm

Oh…. I live in Perth, Western Australia…..

Mark T on September 19th, 2014 at 1:55 pm

Richmond VA

We collected a mud cocoon and were expecting a potter wasp, out popped this guy. What a cool find!

Marisa on October 15th, 2014 at 11:49 pm

One got into my dorm room. I thought it was a horse fly but when it wouldn’t die after I hit it with a broom I realized it had to be some type of wasp. Since I’m allergic to stings and I didn’t know what kind of wasp this was I needed to get rid of it asap. When I finally killed it I saw the stinger. – San Antonio, TX

Ben on October 17th, 2014 at 7:00 pm

Just found one curled up into a ball in my bedroom it had 3 blue stripes and I realized it had a stinger. Cut it in half to make sure it was dead. I got scared and thought i was like a parasite or something (bot fly) but it is just a wasp. Virginia Beach, VA

Patrick on October 23rd, 2014 at 11:14 am

Just had one land on my notepad while trying to write an outline. Absolutely magnificent colors. It just kinda sat there for a few minutes, not moving, then flew off. My face was maybe a few inches away from it. – Summerville, SC.

joseph anthony on October 27th, 2014 at 4:39 pm

Just found one crawling around the window sill. Really nice meetallic blue and green. Goodyear, AZ

Di Sheidow on November 22nd, 2014 at 3:52 pm

Found and filmed one checking out a giant mud wasp’s nest for a way in. Glorious colours. We don’t kill any of the critters on our rainforest acreage – and unless you accidentally bump into something, it’s rare to get bitten. Our home is at Tanawha on the Sunshine Coast, Queensland, Australia, so these gorgeous little guys are certainly widespread.

Leave a Comment

Name

Email

Website

Comment