Are you confused about how to classify the beautiful, metallic-colored insect hovering around your garden? This article will explain to you how to differentiate between Cuckoo wasp vs Sweat bee.
Both the Cuckoo wasp and the sweat bee (or metallic bee) display brilliant metallic colors and have very similar anatomies.
It is often hard for even the most experienced insect lover to differentiate between the two.
But if you stick around and observe these bugs closely, there are several things that can help you identify the key differences.
In this article, we will look at some of the points of difference between these two insects.
What Are Cuckoo Wasps?
Cuckoo Wasps are from the Chrysididae family of hymenopterans. More than 3,000 species of these wasps are described.
Cuckoo wasps are kleptoparasitic wasps. To those unanointed with scientific terms, kleptoparasitic means they are parasites by stealing. That’s a fancy way of saying they don’t just eat their prey; they steal from them too!
Cuckoo wasps often lay their eggs inside the nests of other wasps (hopefully when the other female is gone away).
These eggs hatch before the host wasps own do, and they feed off the food that the host wasp has left for her larvae.
Later, when the larvae of the host wasp hatch, they feed on those too. All in all, these wasps are the devil incarnate.
Unfortunately, the devil wears Prada, and so do these bugs. Their beautiful shimmering metallic colors often enchant humans who notice them.
Cuckoo wasps are often found in deserts because the host bees and wasps they like to steal from also live in these areas.
These insects have evolved amazing defense mechanisms to aid their dangerous lifestyle, such as mimicking the smell of their hosts and curling up in a ball with their powerful exoskeleton to protect them.
What Are Sweat Bees?
Sweat bees are part of a family of bees known as Halictidae. There are over 4,500 species of these bees. Many of them can look very different from each other.
Halictidae are abundant in nature, and you can find these bees flitting around gardens and yards all over the world.
They can be metallic colored (most often), but they can also be black or brown. Their sizes and the patterns on their back vary from species to species.
Most of them are between a quarter to three-quarters of an inch in length
Some have green hues, others red, and a few blue and even purple! One thing commonly found in most of them is yellow-colored markings. The males almost always have them.
These bees have short tongues, and they have a curved basal vein near their wings. In most cases, females are larger than males.
One interesting fact about them is that their name, “sweat bees,” comes from the fact they are drawn toward human sweat!
Differences Between The Two
Due to their similar metallic colors, they are often difficult to distinguish from each other. However, there are some interesting differences in their nesting behaviors, the way they move, and their appearances. Let’s look at these points more closely.
Behavior
The first key difference between the two is that cuckoo wasps are not particularly fond of sitting on flowers.
Even though both cuckoo wasps and sweat bees take nectar as their food, you will probably not find the cuckoo wasp around flowers as much as their lookalike bees.
Both wasp and bee have one thing in common, though – they both love honeydew.
Plants that have aphid infestations will often see both these insects buzzing around them in the hopes of getting a taste of the sugary substance.
Movement
Cuckoo wasps, like most other wasps, have a jerky, erratic way of flying. They would dart around in mid-air and alight and fly about in quick movements. Their flights are not very serene.
Sweat bees fly in a more slow and steady fashion, like a traditionalist. They would sit on one flower, suck the nectar, then alight slowly, flying to the next one, and then sit there again for some time.
Their movements in the air and on and around the flower are quite poised.
Preening
Both types of insects preen, but the sweat bees tend to take longer to do so. Both will stop at flowers or branches and go about their business, but male sweat bees also keep a lookout for the ladies during this time. Perhaps trying to show off their beautiful, well-oiled skin?
Pollen collection
Cuckoo wasps may be nectar drinkers, but they are no pollinators. They do not carry around pollen with them after having a drink on a flower.
Female sweat bees carry pollen back to their nests. They have hair brushes on their hind legs called scopae, which help keep the pollen in place as they make their journey.
In this aspect, they are just like any other bee.
Appearance
Not all sweat bees are completely metallic in color. For example, the Agapostemon, a type of metallic green sweat bee, only has the head and thorax in this color.
The abdomen of the males of this species is the more traditional striped yellow and black. Females have completely black abdomens with white hairs on them.
Nesting
As we mentioned earlier, cuckoo wasps are kleptoparasites. Since they simply place their eggs in other wasps’ nests, they don’t need to make a nest of their own.
Sweat bees, on the other hand, make their own nests. They typically either burrow their nests in the ground or else look for small gaps in the barks of trees to make one.
Since the parasitic activity of the cuckoo wasps also involves searching for nests in the barks of trees, you might find both types of insects investigating trees in the same area. But their purposes are very different from each other.
Some species of sweat bees also follow communal nesting, where several females share the same nest. In such cases, you might often find a nest guard near the entrance, looking out for predators and keeping the nest safe.
Frequently Asked Questions
Can a cuckoo wasp sting you?
No, female cuckoo wasps don’t have a stinger. They have something akin to a stinger known as an ovipositor, which they use to deposit their eggs in the nests of the wasps who act as their hosts.
Despite the fact that their stingers are basically non-functional, some people have claimed that these wasps can actually sting you, especially members of the larger species among them.
Why is it called cuckoo wasp?
Cuckoo wasps are kleptoparasites; they deposit their eggs in the nests of other wasps. See where we are going with this?
This is a trait called brood parasitism that they share with cuckoo birds, who pull the same stunt on unsuspecting songbirds and other smaller species of birds.
Unfortunately, the cuckoo wasps don’t stop there. Their larvae come out and eat the food kept for the host’s larvae and then kill the host larvae also when they come out.
What is a sweat bee actually called?
Sweat bees are so called because of their penchant for being attracted to human sweat. But these bees are actually from the family Halictidae, one of six families belonging to the Hymenoptera order.
Not all halictids are metallic, but many are. These bees are more abundant than most others if you leave out honey bees.
What type of bees are most aggressive?
Many types of bees are aggressive, but the Africanized honey bee is considered one of the worst. It can attack almost anything that dares enter anywhere near its beehive.
Other bees that are considered very aggressive are killer bees and yellow jackets.
Are yellow jackets and sweat bees the same?
No. Even though these two species are widely confused for each other, they are not the same. Yellow jackets are very aggressive, as we mentioned earlier.
They will not leave anyone coming near their nests alone.
Sweat bees are protective of their nests too, but they are nowhere near as aggressive as yellow jackets.
Wrap Up
Both cuckoo wasps and sweat bees are a sight to behold in your garden when they are moving from flower to flower. Both have mesmerizing colors and patterns on their bodies.
But perhaps even more interesting are the ways in which these insects have uniquely evolved to survive and thrive in their environment.
For two species that look so similar, the differences are really remarkable. Thank you for reading!
Reader Emails
Cuckoo wasps are rather unique in appearance, and they often get confused with flies and bees (such as the sweat bee).
Read below some confusion-filled letters from our readers over the years, asking us to detail these beautiful wasps.
Letter 1 – Cuckoo Wasp or Not
Blue Wasp
Hello bugman, I took a pic of a blue wasp that was stuck in the window. Do you know what it is? I am from Vancouver Island, B.C., Canada.
Thanks
Kathy
Hi Kathy,
You have a beautiful Cuckoo Wasp, Family Chrysididae. These small wasps are usually metallic blue or green in color. They get their common name because, like the Cuckoo bird, the wasp is parasitic. According to Hogue “it lays its eggs in the nests of bees and other wasps. The larva kills the rightful occupant of the nest and develops on the provisions left in the cell by the nestbuilder.”
Update (07/29/2007) Believe you have a misidentification on a previous i.d.
Daniel: In looking for pictures of a cuckoo wasp (for which I have a nice pic I could send although you already have several), one of your identifications looks misidentified. If you look at the the pictures from Timothy and Tarik — which I believe you have identified correctly — you’ll see a generally rough looking ‘back’, and the thorax sections are not sharply separated. Also, the legs are skinny, the antennae are short, and the center of the abdomen is more bulbous than the rest. In contrast, if you look at the photo from Kathy, the back is smooth, the thorax is sharply segmented, the ‘thigh’ of the front leg is ‘muscular’ looking, the antennae are quite long, and the abdomen is fairly similar in thickness throughout its length. Not to mention that the overall color is more brilliantly blue, less green than the other photos. A check of other images on the internet shows a much closer resemblance to the blue wasp, “Aporus hirsutus”. The best example of this is found at: http://bugguide.net/node/view /31105/bgimage In particular, note the beefy upper front leg, long antennae, and other consistencies with Kathy’s image.
Oops! While I believe you still have a misidentification, another glance at the Blue Wasp photos show that this is not the correct i.d., either. I just noticed that there are two smaller photos below the larger one on the bugguide.net page, and the rear legs are cricket-like, which is clearly not the case in Kathy’s photo. I am now thinking that it at the least looks more like “Augochlorella striata” than something in the Chrysididae family. See: http://www.cedarcreek.umn.edu /insects/newslides/025066011001 apo.jpg But the smoother, more segmented back in Kathy’s photo doesn’t agree, along with the bluer color. So, I don’t think that it is any of the bugs you or I mentioned, and thus remains unidentified. Curious to hear your opinion.
Mark
Letter 2 – Cuckoo Wasp
Cuckoo wasp?
Hi – found this bug on our tent while camping in south-central Wisconsin. I searched your site and think this might be a Cuckoo wasp? Just wondered if it is and if not, what is it? Sure is beautiful. As always – I love your site and visit it often. I have a link to it on my own blog and always tell my friends about it – fantastic resource. Thanks!
Ann Graf
Hi Ann,
This is a marvelous image of a Cuckoo Wasp in the family Chrysididae.
Letter 3 – Cuckoo Wasp
Great website for all!
Here is a bee-like animal that I discovered in two different areas of central Florida. One is at the Wekiva River Basin State Parks in Apopka Florida, and the other is at my house in Ocala Florida. In both situations the animals were using and very interested in small openings about the size of the animal. At the park, there were as many as 25-50 individuals swarming in and out of these openings (I am not sure of whether they created them or another animal, but they were certainly not rotted wood openings and were made by an organism. At my house, there was only this single individual seen, and it was trying to use an opening into our cement block house which I had made previously with a screw. It was actually in some sort of conflict with another wasp-like animal to use the small opening when I discovered it. Anyway here is a photo of that animal at my house. The small opening is seen in the background. Any idea of the species?
Thanks, Rick
Rick Owen, Park Biologist
Wekiva River Basin State Parks
Apopka, Fl
Hi Rick,
The wasp in your photo is a Cuckoo Wasp in the family Chrysididae. Species are nearly impossible to distinguish from one another. They lay their eggs in the nests of host insects, usually wasps and bees. The social behavior you describe does not seem consistant, but perhaps a swarm of Cuckoo Wasps were attacking a colony of other insects, or perhaps you witnessed a hatching of a brood.
Letter 4 – Cuckoo Wasp
What kind of bee is this?
This picture was tooken in Russell Springs, Kentucky at our family cabin. And no one had seen this kind of bee there before, What kind is it? can someone tell us?
Thank you
Tina M. Huckaby
Hi Tina,
We contacted Eric Eaton who wrote back that this metallic wasp: “is actually a cuckoo wasp (Chrysididae), probably in the genus Chrysis. They do not sting, and in fact roll up in a ball as a defense if they are molested.”
Letter 5 – Cuckoo Wasp from Australia
Cuckoo Wasp?
Dear Bugman,
I think I have a Cuckoo Wasp in my garden but I’m not sure. I’ve seen it on my flowering Sedum for the last few days. Collecting honey I guess along with many honey bees. I live in the southwest of Western Australia. It’s the first time I’ve ever seen this bug…totally blown away by its amazing colours!
Julia Parkes
Hi Julia,
Thank you for sending in your beautiful image of a gorgeous Cuckoo Wasp. The Geocities website has some additional photos of Australian specimens.
Letter 6 – Cuckoo Wasp
Sorry to bother you, I found an interesting bug!
Ok, it’s interesting to me. I’m in Northern Virginia, and I found this shiny green guy on the windowsill of my son’s room. I searched your site, but couldn’t find anyone like him, I’m sure it’s just a lack of looking in the right place. Anyhow, here are some pictures. Please be assured that we had nothing to do with its demise, I only observe, and I release anyone who gets trapped, but sometimes I don’t find them in time. 🙁 You can see by the other pictures on my house critters page that I don’t harm anything, I appreciate the symbiosis. I didn’t put anything in the pictures for a scale reference, I realize now, but curled up like it is, it’s about the same size as my pinky nail, fairly small. Anyhow, many thanks if you have the time to let me know what it is!
bri..
Hi Bri,
This pretty little creature is a Cuckoo Wasp in the family Chrysididae. We have several photos on our wasp pages. In this rigor mortis pose, it rather reminds us of the Mickey’s Malt Liquor mascot.
Letter 7 – Cuckoo Wasp
Can you tell me what this is?
Location: Australia, NSW, Western Sydney area.
February 5, 2011 11:22 pm
Hi bugman, I found this bug in my laundry about 2 weeks ago. I put it into a bug-catcher to get it out of my laundry and so that I could let my son have a good look at it and then I was going to let it go. It was dead when I got up the next morning and looked like this (see photos). It is summer here at the moment and been particularly warm between 36-40 degrees centigrade/celcius. I hope you can help. I thank you in advance 🙂
Signature: Not sure what this means?
Dear Not sure what this means?
This sure appears to be a Cuckoo Wasp, possibly the Large Cuckoo Wasp, Stilbum cyanurum, which we located on the Brisbane Insect website. According to the Brisbane Insect website: “The adult Cuckoo Wasp’s back is well armored and with abdomen concave beneath. When disturbed, it curl up into a ball. This is a defense behavior against the attack by angry nest host.” Perhaps your individual rolled into a ball in self defense before it died. Though it was not intentional on your part, keeping an insect in a confined container and then finding it dead might constitute Unnecessary Carnage.
Letter 8 – Cuckoo Wasp and Ambush Bug from Canada
2 interesting bugs
Location: Kitchener Ontario Canada
September 29, 2011 2:55 pm
Hi, Bugman
I have 2 bugs that I am curious about..
The first was found deceased on my windowsill, even so very pretty insect.
The 2nd Yellow bug I found today has the shape of an assassin bug almost from the top but I noticed mantis like hooked forelegs when viewed from the side.
Thanks
Signature: Martzart
Dear Martzart,
The beautiful metallic blue insect you found dead in your car is a Cuckoo Wasp in the family Chrysididae. Your yellow insect is an Ambush Bugin the subfamily Phymatinae. In the not too distant past, Ambush Bugs were classified in their own family, but recent taxonomy has reclassified them as a subfamily of the Assassin Bugs.
Letter 9 – Cuckoo Wasp from Portugal
Subject: Colourfull fly
Location: Portugal
May 16, 2015 11:37 pm
What kind of fly is this?
Never saw this one before….
Signature: Tineke
Dear Tineke,
This looks like a Cuckoo Wasp to us, but the red abdomen is something we do not see in North America. It might be Hedychrum rutilans which is pictured on Shutterstock. There is also some information on Chrysis.net. Cuckoo Wasps can curl up for protection when disturbed or threatened as your image indicates.
Thank you very much Daniel for your quick respons…
Its a beautiful insect, it was dead when I found it and I keep it in a little box.
Best regards,
Tineke
Letter 10 – Cuckoo Wasp from Scotland
Subject: Fly or wasp
Location: NT22217222
July 27, 2015 11:48 am
Picture taken 25th June 2015.
Abdomen and thorax colouring of Chrysidid wasp, head of a fly?
Any help with ID would be greatly appreciated.
Cheers,
Signature: Stevie in Edinburgh
Dear Stevie,
We believe the similarity to the head of a fly in your image is an illusion, and that your Cuckoo Wasp is Chrysis ignita which is pictured on BWARS where it states the species is found: “Throughout England,Wales, Scotland and Ireland but not found on the Orkney and Shetland Islands. Recorded from the Isle of Man, Isle of Wight, the Isles of Scilly and the Channel Islands.”
Letter 11 – Cuckoo Wasp: Pseudomalus auratus
Subject: Tiny bee
Geographic location of the bug: Billings MT
Date: 08/14/2018
Time: 06:19 PM EDT
Your letter to the bugman: Green head and abdomen, iridescent orange thorax, size of a small grain of rice. I was totally fascinated by this insect. It was foraging on a sunflower leaf. As it was walking away, it’s thorax shone like a high beam orange light! Unfortunately the glowing photo was a blurry but gives you an idea of the orange glow I was seeing.
How you want your letter signed: Lisa Gerard
Dear Lisa,
What a beautiful little gem you have discovered, but it is a Cuckoo Wasp, not a Bee. Thanks to this and other images on BugGuide, we identified your Cuckoo Wasp as Pseudomalus auratus. According to BugGuide: “native to, and widespread in the Palaearctic, introduced in NA (e. US, UT, CA…)” and “‘The wasp oviposits inside the aphids but it gets more complicated. The aphid with a chrysidid egg inside must be captured by crabronid wasp and taken to its nest. Some crabronids hunt aphids for food provision to their offspring. Later, inside crabronid wasp’s nest the chrysidid egg will hatch, kill crabronid larva and consume the food provision (aphids). This is how chrysidid gets her egg inside the crabronid wasp nest without risking entering to the nest herself.’ (Villu Soon, 11.vii.2017).” It is also pictured on Bees, Wasps & Ants Recording Society and on Bug Eric,where it states: “Larvae of this wasp are kleptoparasites in the nests of other solitary wasps, and solitary bees, that nest inside hollow twigs, pre-existing cavities in wood, and similar situations. Known hosts include the smaller wasps in the family Crabrionidae, and bees in the genera Ceratina (small carpenter bees, family Apidae), Hylaeus (masked bees, family Colletidae), and Anthidium (wool-carder or cotton bees, family Megachilidae). The cuckoo wasp grub feeds on the provisions stored by the mother of the host larva. They literally steal the meal provided by the host for its offspring.”
Letter 12 – Cuckoo Wasp
Subject: Trying to identify what this bug is
Geographic location of the bug: Tennesse, Knoxville
Date: 10/24/2021
Time: 06:36 PM EDT
Your letter to the bugman: Can someone pls tell me what this bug is, I’m low key a little scared.
How you want your letter signed: Nick Cooper
Dear Nick,
Fear not this beautiful metallic Cuckoo Wasp. They do not sting. Cuckoo Wasps are often found dead indoors near window sills. They get trapped indoors accidentally and eventually die while being attracted to the view outdoors.