In this article we discover the symbiotic field digger wasp and fly relationship. It will help you understand that symbiosis can be of many types, and this one is quite unique among others.
It can be hard to imagine species apart from humans – be it animals, birds, or insects – coexisting peacefully.
In fact, most social animals remain with their own kind.
However, among insects, it’s not rare to see different species share some sort of give-and-take interaction.
Usually, such interactions end up increasing the survival chances of both parties or at least allowing one to take advantage of the other.
The field digger wasp and the fly share a similar relationship. Today, among the various abilities of insects, we are going to discuss symbiosis.
What Is a Symbiotic Relationship?
A symbiotic relationship refers to the relationship between any two organisms that interact in a way that either one or both parties benefit.
While symbiotic relationships can be either of the 4 types – mutualism, commensalism, parasitism, and competition – the term is generally used by laymen to refer to mutualism.
Common examples include fish that keep corals clean while enjoying the shelter the corals provide.
Another one is that of barnacles that stick on whales and get to travel for free without harming the whale.
Usually, symbiosis is only used for two dissimilar species of animals that share a relationship.
What Is the Relationship Between Field Digger Wasps and Flies?
The field digger wasp, or Mellinus arvensis, is a solitary digger wasp found burrowing in the ground. They share a parasitic relationship with flies.
These ground-nesting insects create nests in vertical burrows within the sand or sometimes within bales of straw and hay.
The underground nests attract flies, which then become food for the larvae of the wasps.
Sometimes, an adult wasp will kill an ant and drag it to its nest. Sometimes they hunt other insects and bring them into the nest.
The carcass attracts ants, which are then killed later by the larvae.
In fact, digger wasps have evolved to form many symbiotic relationships. For example, the beewolf digger wasp species harvests the Streptomyces bacteria within their antennal glands.
These bacteria are then applied to the cell that contains the larvae.
The bacteria form a part of their pupa, protecting them from certain infections.
While scientists don’t fully understand the process, it is believed that the antibiotics produced increase the larvae’s chances of survival.
How Is the Relationship Symbiotic?
As discussed, symbiosis has four types. A mutually beneficial symbiotic relationship is one where both parties benefit from the interaction involved.
Commensalism is when only one party benefits while the other is neither harmed nor helped.
Parasitism refers to when only one party benefits from the other (and eventually kills the host).
Finally, competition refers to two organisms competing within an ecosystem, where each keeps the other in balance.
The field digger wasps and flies share a parasitic symbiotic relationship, where mostly the digger wasp benefits at the expense of the fly.
Other Symbiotic Relationships in the Insect Worlds
This behavior in insects is not uncommon, and many insect species share symbiotic relationships with other insects and animals.
Some common examples are:
Army ants and Mites
Army ants construct large nests on the ground, which host a variety of other insect and parasite species as they pass through.
One common guest is the mite E. burchellii. These mites attach to the ants legs and draw blood, which they then sustain.
Their bite does not hurt the ant; however, the ant does not benefit from it either (or at least, it is not clear to us yet).
Carrion Beetles and Mites
Some mite species will take a ride on carrion beetles. The beetle will transport the mite across a large distance, which the mite itself could not have covered.
In turn, the mites feed on the larvae and pupae of other insects, which could have threatened the beetle’s own eggs.
Leaf Cutting Ants & Fungi
Leaf-cutting ants harvest their own fungus within a fungus garden to feed on. They will cut portions of leaves and take them to their fungus garden (or cultivation area).
This allows the plant fungus to grow well on the decaying matter. The ants provide the right conditions for the fungus’s growth and, in turn, feed on the fungus itself.
Aphids and Ants
Aphids produce a substance called honey-dew, which ants feed on.
In turn, ants will allow aphids to live within their colonies and protect them from other predators.
This is a mutually symbiotic relationship.
Most insects harbor microorganisms in their guts or body cavities.
These microorganisms can help with preventing infections, or in some cases, they can negatively control the host’s behavior.
Often, these microorganisms are passed down through the generations. This is an example of microbial symbiosis.
Symbiotic relationships are also seen within the animal kingdom.
In fact, humans also share a similar relationship with the millions of microbes in our gut, who help with digestion in exchange for a home.
Thank you for reading.
Frequently Asked Questions
What is the symbiotic relationship between trees and mistletoe?
Mistletoe is a parasite that extracts nutrients from its host spruce, weakening it and leading to the development of “witches’ brooms,” – bundles of excess growth.
The symptoms of mistletoe infestation include abscessing, an abundance of buds and tangled twigs, foliage residing in the broom, and early death in unaffected branches.
Although damaging or lethal to the spruce in question, mistletoe can provide shelter for animals like American martens, as well as be used by tribes like the Mistassini Cree Indians in rituals that involve burning witches’ brooms.
What type of symbiotic relationship is a wasp?
Field digger wasps share a parasitic relationship with flies, as these ground-nesting insects create nests in vertical burrows within the sand to attract flies, which then become food for the larvae.
They also have other symbiotic relationships, such as harvesting the Streptomyces bacteria within their antennal glands, which they apply to their larvae’s cells to protect them from certain infections.
This relationship helps increase their chances of survival.
What genus is a digger wasp in?
Sphex (digger wasps) are predators with over 130 known species.
They sting and paralyze insects for food, and construct protected “nests” for egg-laying – some species dig holes in the ground while others use pre-existing holes.
The great golden digger wasp have female wasps that build as many as six nests a summer, which the larvae feed on when they develop.
Behaviorally, Sphex has been observed not being able to count how many insects it has collected or adjust how it drags its prey when it has lost or misplaced one – though instinctively continuing to search for four crickets.
What type of symbiotic relationship is the intestinal worms and mammals?
Parasitism is an interaction between two organisms where one benefits while the other suffers harm. Parasites feed on their hosts, depriving them of essential nutrients and leading to reduced health.
The symbiotic relationship between these two insects is often confusing because most people only understand mutual symbiosis.
Go through some of our reader emails that depict this confusion in abundance.
Letter 1 – Digger Wasp
What is this Bug? I found this bug near Oracle Az. Was wondering what it is. Hi, We believe your beautiful Red Tailed Wasp is a Digger Wasp, Scolia dubia. The female digs a nest in the ground and provisions it with beetle larvae. We will contact Eric Eaton who lives in Arizona to see if he can confirm our identification. Here is what Eric has to say: ” Hi, Daniel: I think Earthlink owes you an explanation! I mean a ‘better’ one:-) Geez. Hey, feel free to divert folks to Bugguide where they can “post their own,” if that would help you any. The wasp: Right genus, but wrong species. It is a male (long, straight antennae, small body) Scolia ardens. They are quite common right now. I have taken them on blooming eucalyptus here in town, and blooming salt cedar in another part of the county. I almost miss hearing from you so often:-( Keep up the great work. Eric”
Letter 2 – Digger Wasp
Would appreciate any assistance
Thank you for your really fun (and educational, of course) site. I have enjoyed it immensely. We recently moved to Central VA and have been fascinated by the many new bugs we have found on our 3 acres. This past week our lawn has been benignly "invaded" by the attached bug. With a 2-year old and a 3-year old we were alarmed by seeing what seems like a couple hundred wasps flying over and through the (very) long grass. They have acted utterly harmless, though, and even tolerated me mowing the lawn – effortlessly moving out of the way and then back to their flightpaths. They don’t sit still often and finally I caught one on camera. Any thoughts? They just roam endlessly 6 inches over the lawn, often congregating but rarely stopping. Hard to tell in this photo, but the "tail" is orange and black striped and covered in tiny hairs. You are probably overwhelmed with requests for your expertise, but if you have any information I would greatly appreciate it! All the best,
This is a Digger Wasp, Scolia dubia. Thanks for the excellent first hand behavior observations.
Letter 3 – Digger Wasp
wasp moth? Hello,
I just downloaded a bunch of photos of wonderful bugs shot in weed patch along the edge of a small wooded area in Northampton, PA. Most of them were bees and wasps. This one was different than most of them and at first I thought it might be a wasp moth. After looking at your site, it appears it could be a digger wasp, but I couldn’t quite tell from the photo. You are welcome to use this photo if you wish. I cropped it so it would not clog your server. I have a larger, uncropped version too if you want. But this one cuts to the subject pretty well. I also got a great photo of a Wheel Bug devouring a bee while a wasp gathered nectar within 2 inches of it. I’ll send that under separate cover. Thanks
This is a real wasp, a Digger Wasp, Scolia dubia. We posted another photo of this species last week, but since your photo is so much clearer, we are posting it as well.
Letter 4 – Digger Wasp
This lovely creature and its pals visit my apple mint around noon each day. Must be their lunch counter or something. They’re about an inch long and as you can see, have beautiful irridescent blue-black wings. They’re striped like a coral snake (red touch yellow, kill a fellow) and only feast on the mints in my garden, even though there are many other flowers nearby. Is it a wasp? I looked at your site and several others, and can’t find anything that looks like this. Also, is it dangerous? It doesn’t seem aggressive, as the mint is along the side of the driveway and we brush by it getting in and out of our cars and haven’t been stung yet. I hope someone can identify it.
Well, I revisited the wasp section of your site and found that the photo I sent you is of Scolia dubia – a digger wasp. That might explain the little piles of dirt on the opposite side of the driveway that I blamed on ants or beetles. I’ll have to check this out. I’ve never seen the wasps on the lawn or anyplace else except the mint. Go figure! Hedy Hadley
You are correct. This is a Digger Wasp, Scolia dubia.
Letter 5 – Digger Wasp
Hi! Love the site and I enjoy looking at all the different species of wasps. This little guy (about 1" or so) showed up in my back yard about a week ago along with about 4 million of his brothers and sisters. They seem to be dwelling in the ground. The closest thing I’ve identified them with is the Cukoo Wasp. Any ideas? Thanks.
This is a Digger Wasp, Scolia dubia. Adult wasps prey on the grubs of June Beetles as a food source for the larval wasps.
Letter 6 – Ukrainian Digger Wasp is Mammoth Wasp
identification help Hello dear Sir, could you help me please to identify this giant insect. Here some info for identification help: This insect is about 5 cm (2 inches) longwise. Was found in the tropic area of Crimean mountains (Ukraine). Looks like it lives into the burrow or hollow of the old tree stub. It was alone there. Thank you Lora Hi Lora, This is a Digger Wasp in the family Scoliidae. Scoliid Wasps are hairy, robust wasps that prey upon the ground dwelling grubs of Scarab Beetles. The adult wasps feed on nectar, and the beetle grubs are food for the larval wasps. There is a close enough resemblance to a North American species, Scolia dubia, that your specimen might be in the same genus.
Letter 7 – Digger Wasp
Wasp, Black and Rust with Two Yellow Spots October 4, 2009 I photographed this beautiful wasp October 2009 in NE Oklahoma. It is similar in size to a red wasp and yellowjacket. Bugged about Bug Northeastern Oklahoma Dear Bugged, This is a Digger Wasp or Blue Winged Wasp, Scolia dubia. According to BugGuide: “Adults take nectar, may also feed on juices from beetle prey. Larvae a parasite of the green June beetle and Japanese beetle.“
Letter 8 – Digger Wasp
Are these bugs wasps? Location: Eastern Pennsylvania August 14, 2010 10:30 am Hi, I’ve noticed a large number of bugs today flying close to the ground in our backyard. They look to be Black bodied,with 4 dark colored wings that fold into one. The rear part of their body, however, is brown and has 2 distinct yellow spots. I’m trying to figure out if they are wasps. Sorry my pictures aren’t too good, I caught one in a Tupperware container. Benjamin Williams Hi Benjamin, This is a Digger Wasp, Scolia dubia, and BugGuide has some interesting information about it, including: “Males and females have a courtship dance, flying close to the ground in a figure-8 or S pattern. Females burrow into ground in search of grubs, especially those of the Green June Beetle, Cotinis, and the Japanese Beetle. She stings it and often burrows farther down, then constructs a cell and lays an egg on the host. Larva pupates and overwinters in a cocoon within the body of the host. One generation per year in North, more in South.“
Letter 9 – Digger Wasp or Blue Winged Wasp
Feeding on Goldenrod Location: Southern New York State August 16, 2010 4:18 pm Saw this beautiful bug feeding on goldenrod in early August. It is about 1/2” long and unfurled gray wings under the colorful shell and flew short distances when disturbed. Also the unidentified wasps were busy at work. Cicada killer? Don HI Don, The image of yours that we are not posting is an Ailanthus Webworm Moth, a species we have posted several times in recent weeks. We also just recently posted an image of a Digger Wasp or Blue Winged Wasp, Scolia dubia, but it was photographed in a tupperware, not in its natural environment like your lovely photo. Like many wasps, the adult Blue Winged Wasp feeds on nectar while the larvae are predatory. Since they are not terribly mobile, the female wasp provisions for her brood. In the case of the Blue Winged Wasp, the female locates and stings to paralyze the grubs of the Green June Beetle and the Japanese Beetle. According to BugGuide: “Males and females have a courtship dance, flying close to the ground in a figure-8 or S pattern. Females burrow into ground in search of grubs, especially those of the Green June Beetle, Cotinis, and the Japanese Beetle. She stings it and often burrows farther down, then constructs a cell and lays an egg on the host. Larva pupates and overwinters in a cocoon within the body of the host. One generation per year in North, more in South.” According to Mom, any creature that preys upon Japanese Beetles is aces in her garden. Fantastic! My daughter and I love your site. Thanks a million.
Letter 10 – Digger Wasp
Are these cicada killers ? Location: Springfield, MO USA December 20, 2010 2:39 pm I’ve got these wasps that are common visitors to my chive garden when it’s in bloom (BTW Chives make great bug attractants for photography). I think from browsing here that they maybe cicada killers. Would you confirm? Signature: Tom Hi Tom, The Cicada Killer and your wasp, Scolia dubia, commonly called a Digger Wasp or Blue Winged Wasp, are in completely different families, though they are both robust wasps that dig an underground nest for their brood. While the Cicada Killer preys upon Cicadas, the Digger Wasp preys upon the grubs of June Beetles and thankfully, Japanese Beetles, an invasive species whose imago feeds upon possibly hundreds of different cultivated plants, including roses, rose of Sharon, daisies, fruit trees like peach and apple, blue berries … . According to BugGuide, the Digger Wasp: “Males and females have a courtship dance, flying close to the ground in a figure-8 or S pattern. Females burrow into ground in search of grubs, especially those of the Green June Beetle, Cotinis, and the Japanese Beetle. She stings it and often burrows farther down, then constructs a cell and lays an egg on the host. Larva pupates and overwinters in a cocoon within the body of the host. One generation per year in North, more in South.” You are sure right about chives attracting nectar loving insects, and we also find, in our Mt. Washington, Los Angeles office, that allowing onions and carrots to flower makes for an attractive garden to beneficial insects. You made my day. My neighborhood has a bad Japanese beetle problem. Anything, that kills those monsters is welcome I my yard. 😀
Letter 11 – Digger Wasp
Subject: What kind of bug is this? Location: East-Central PA September 9, 2012 6:04 am This many of these bugs are swarming in my vegetable garden. Signature: Jim’s Bug Hi Jim, This is a Digger Wasp or Blue Winged Wasp, Scolia dubia. Female Digger Wasps prey upon the grubs of Green June Beetles and Japanese Beetles in order to provide food for her brood. For that reason, Digger Wasps should be considered beneficial and there presence should be tolerated in the garden. Adult Digger Wasps feed on nectar, and since they are solitary wasps, they are not considered aggressive. It is possible that one might be stung if an attempt is made to handle a female Digger Wasp. Male Digger Wasps cannot sting. For more information, you should see BugGuide.
Letter 12 – Digger Wasps
Subject: Bug identification Location: Fall Branch, TN 37656 August 22, 2013 7:10 am These bugs have invaded my apple trees! They’re not eating the fruit, just killing/eating the leaves. Most are 1-1 1/4” long. Wings look irredescent. They are avoiding my pear, cherry, peach and apricot trees and just on my apple. I thought they might be a type of bee but they have not stung me. There are about 25-30 per tree. Signature: Whats That Bug This appears to be a Digger Wasp or Blue-Winged Wasp, Scolia dubia, and we cannot understand why they are congregating on your apple trees. According to BugGuide: “Males have longer antennae than females, and a pronglike pseudostinger on the abdomen” so we believe your individuals are males. We wonder if males roost together at night in “bachelor parties” similar to those of certain solitary bees. Eric Eaton has written about this phenomenon on Bug Eric.
Letter 13 – Digger Wasps dead from Natural Causes!!!
Subject: What wasp is this? Location: Upper Marlboro,MD August 23, 2013 6:01 am Approximately 3/4”flying in swarms several inches above turf.No obvious ground holes. Signature: JFR Hi JFR, We are so sad, and we are hoping that by posting your images and tagging them as Unnecessary Carnage, we will educate both you and our public about these beautiful and beneficial Digger Wasps or Blue-Winged Wasps, Scolia dubia. They are solitary wasps and they are not an aggressive species, despite the stinging capabilities of the females. Males do not sting. According to BugGuide: “Larvae are parasites of green June beetles and Japanese beetles” and “Males and females have a courtship dance, flying close to the ground in a figure-8 or S pattern. Females burrow into ground in search of grubs, especially those of the Green June Beetle, Cotinis, and the Japanese Beetle Popillia japonica. She stings it and often burrows farther down, then constructs a cell and lays an egg on the host. Larva pupates and overwinters in a cocoon within the body of the host. One generation per year in North, more in South.” Japanese Beetles are an invasive exotic species that can decimate an ornamental garden if there are large numbers. Any insect that helps to control Japanese Beetle populations naturally is beneficial. We hope you will reconsider your original impulse to eradicate these majestic Digger Wasps and allow nature to keep any population balance of potential pest insects in check. CORRECTION: NOT Unnecessary Carnage Hi Daniel.. I actually found these two deceased and in no way contributed to their demise. After I submitted my request to you I searched the web and was able to I’d them and it makes sense that they are there given the presence of Japanese Beetles in the area. Thanks so much for the clarification. We are happy that no carnage was involved These appear to be males, and males do not live as long as females. Male Digger Wasps likely die shortly after mating while females need to live longer to hunt and lay eggs.
Letter 14 – Metallic Sweat Bee, Digger Wasp and Potter Wasp attracted to blossoms
Subject: Colorful Wasps of Summer Location: Central Maryland, USA August 27, 2013 10:04 am Bugman, the wasps and bees really like this particular hemlock weed with many colorful varieties visiting it today. Looks like a Metallic Sweat Bee, a Digger Wasp, and one other black/white wasp. Would the black wasp with white bands possibly be a type of Mason Wasp? Signature: Roger S. Hi Roger, Generally we don’t like making postings with diverse insects, but all your pollinators are in the order Hymenoptera, and they are all visiting the same blossoms for the same reason, to feed on nectar, so we are making an exception. We agree with your identifications of the Metallic Sweat Bee which looks very much like this image on BugGuide, and the Digger Wasp, Scolia dubia. The third wasp is most likely a Potter Wasp and we believe it is in the genus Eumenes, which you can find pictured on BugGuide, however, we were not able to confirm a species identification.
Letter 15 – Digger Wasp
Subject: Wasp Location: Pennsylvania August 19, 2015 1:51 pm We have these wasp in our yard think they have a nest underground how do we know for sure and get rid of it Signature: Sharon Dear Sharon, This is a solitary Digger Wasp, Scolia dubia, and it is not an aggressive species. They develop underground, but they are not social wasps with hundreds of members of a colony. According to BugGuide: “Males and females have a courtship dance, flying close to the ground in a figure-8 or S pattern. Females burrow into ground in search of grubs, especially those of Cotinis and Popillia japonica. She stings it and often burrows farther down, then constructs a cell and lays an egg on the host. Larva pupates and overwinters in a cocoon within the body of the host. One generation per year in North, more in South.” Any insect that preys on the invasive Japanese Beetle is a friend to the gardener. We do not provide extermination advice.
Letter 16 – Digger Wasp
Subject: What is this Location: Hardyville Kentucky August 19, 2015 6:43 pm These have been gathering in my backyard in the mornings. Seems that they are after the dew on the grass. I first thought they were dirt dobbers but I saw a few just chilling on my fence this afternoon and this is the picture. Thanks Signature: Cheryl Dear Cheryl, We are pleased to see your image of a living Digger Wasp, Scolia dubia, and to read your positive attitude about it because these docile, solitary wasps are frequently targeted for Unnecessary Carnage like the dead Digger Wasp we posted a few days back. The female Digger Wasp lays her eggs on subterranean beetle grubs including the invasive Japanese Beetle, so Digger Wasps are a gardener’s friend.
Letter 17 – Fear of the Digger Wasp: Real or Irrational?
Subject: Digger Wasp? Dangerous? Location: Orange, Essex County, NJ August 25, 2015 10:38 am Here are a few pix of this multi-colored wasp-like/-looking thing in my front garden. This is a pic of the first one. I saw one or two others. It seems to really like the ripe raspberries… far more than it likes the tomato flowers. I am lethally allergic to bee stings and wasp stings. Is this thing dangerous to me? I stop breathing, if untreated, in 12 seconds after being stung… and again about 15 minutes after injection with my first dpi-pen. This one didn’t exhibit any interest, or even fear, at my getting close enough to take the pix with my iPhone. Thanks. Signature: Stephanie Dear Stephanie, Thanks so much for taking the time to take your comment and submit a query with images, and though your image quality is quite poor, the distinctive coloration of the Blue Winged Wasp or Digger Wasp, Scolia dubia, makes is identity quickly identifiable. The gap in time between your comment and your query has allowed us to contemplate the matter a bit and we can’t help but to wax philosophically on the topic. You ask: “Is this thing dangerous to me?” so we turned to BugEric who writes: “Males cannot sting, and females are loathe to sting unless physically molested.” Not resisting the temptation to pick up or eat this Digger Wasp might provoke a sting from 50% of their population. We cannot imagine you attempting either of those two possibilities. We suspect your condition might be making you overly cautious, but again, we concur that there is always a possibility of being stung. How great is that possibility? We feel it is quite minimal. According to the University of Florida Extension paper by E.E. Grissell: “Male scoliids are frequently seen cruising close to the ground in irregular figure eight patterns (Krombein, personal communication). A dozen or so may be skimming the soil’s surface, but not be noticed until the eye becomes accostomed to their presence. According to Iwata (1976) a female will land and dig into the soil using first her mandibles and then her fore- and midlegs.” Recognizing the behavior of the sexes may help you to become more aware of the difference between the physical impossibility of being stung verses a minimal chance that you might be stung.
Letter 18 – Sand Digger Wasp from Corfu
Subject: Corfu burrowing bug Location: Central Corfu, Greece August 8, 2017 2:08 am Hi I wonder if you can help please? Today – Aug 8th – in Corfu Greece, we’ve seen this chap burrowing in the garden of our villa. He’s about 2cm long and is Black and Tan with external wings – not folded under a shell. He’s making grumbling chirping noises a bit like a cricket. He’s excavating the hole moving small stones out. Thanks Signature: Helen Dear Helen, We quickly located a matching image on the Insects and Spiders of Corfu site that identifies this wasp as a Sand Digger Wasp, and according to information posted to Jungle Dragon: “Taken in Arillas, Corfu. I saw this sand wasp dragging the bush cricket down the path. The cricket was around 2.5″ in length (body) and this wasp was huge, dragging it as it couldn’t carry the cricket.” Jungle Dragon goes on to identify the wasp as Polalonia, but we question that identification, since according to BugGuide, the members of the genus known as Cutworm Wasps prey on cutworms, not Bush Crickets. This Getty Images page just calls it a Sand Wasp. Only female Solitary Wasps build nests in which to raise a brood.
Letter 19 – Digger Wasp
Subject: Lots of these hovering in yard with sandy soil about 20 feet from our pond Geographic location of the bug: Chesapeake, VA Date: 03/26/2020 Time: 03:43 PM EDT Your letter to the bugman: These act like Scoliid wasps, but don’t look like them. What are they? How you want your letter signed: Ruth Dear Ruth, The family Scoliidae contains several species of Flower Wasps or Scarab Hunters that resemble your individual. The long antennae leads us to believe this individual is a male, and it looks like it might be Dielis plumipes which is pictured on BugGuide.