May 1, 2024

Wasps Debunked

Photos and graphics courtesy of the author.

Often just uttering the word “wasp” elicits the knee-jerk reaction of “What are those things even good for?”. There really are not many animals that can conjure an almost universal fear and disgust in people like wasps do. Images of fierce black and yellow bodies with mandibles grimacing and stingers dripping are likely flashing in the minds of most as they read this. Whether that fear and image is rooted in some vestigial memory of danger from our ape ancestry or conditioned into us through pop culture and media is up for argument. But despite this cloak of fear, we still are, and always will be, surrounded by these beautiful and largely misunderstood creatures. Readers may have some firsthand experience with “nuisance” wasps ruining picnics or maybe have painful childhood memories of welts raised by daring pebbles aimed at paper hives. I can understand how these situations may foster at best a passive avoidance or at worst a lifelong disdain of wasps. But what if I were to tell you most wasps do not even possess a stinger and that this group of insects we call “wasps” provides some of our most necessary ecosystem services, from pest control to pollination? The goal of this article is to expand the definition of “wasp” for the reader while hopefully cutting out any scraps of fear or misconception about them, to then be sewn into a new quilt of curiosity about this truly wonderful branch of life.

Those things that we call “wasps” are members of the insect order Hymenoptera. This group of animals is one of the largest or most speciose groups of organisms on the planet. There are currently more than 150,000 species of wasps described to science with an estimated 1,000,000 species that have yet to be described. Now that’s a lot of wasp!

Between those million plus species there is mind boggling diversity of color, form and behavior with every single species having value. From miniscule feather-winged fairy wasps under 1 mm in length, to massive lightning blue tarantula hawk wasps that fit into the palm of your hand. Hymenoptera even contains organisms that we may confuse as being separate from wasps, such as ants and bees. You got that right; all bees are just fuzzy vegetarian wasps that collect pollen instead of prey to raise their young and all ants are wingless hyper-social wasps with complex colonies to raise massive amounts of their young. In fact, the lineage of wasp that gives rise to bees and ants is one of the handful of invertebrate groups that display high levels of parental care. Adult females invest extreme amounts of time and energy into choosing a suitable nest site to store with food for their young. Some even go as far as digging fake nests to lure parasites away from their own. Wasps are intelligent arthropods with endlessly intriguing life histories that deserve less human dissonance and more attention.

Four images of sawfly with orange bodies and black wings collaged together with the words, Symphyta (Sawflies, Horntails, etc...). Overlaying the text in the lower right corner says, "*No sting! Has saw-like ovipositor."

Shockingly, a common misconception is that all wasps sting and these creatures should be avoided at any cost because of it. The ability of wasps to inflict pain on us humans lies in their possession of a specialized organ called the “sting.” The sting is a modified ovipositor or egg laying organ, used solely for injecting venom into the body of a prey item or predator. Since it once was an organ used for egg-laying, only female wasps have a stinger. It is also highly derived within the Hymenoptera lineage, meaning it evolved much after wasps became a thing. As far as the fossil record can tell, wasps came into being in the Triassic period (roughly 200 million years ago), but it wasn’t until the middle to late Cretaceous (roughly 100 million years ago) that the sting that we know so well came into the picture.

Descendants of the oldest stingless lineages are still around today. They are the dinosaurs of the wasp order and are placed in the suborder Symphyta. Wasps within Symphyta are commonly referred to as Sawflies. Sawflies have mobile caterpillar-like larvae that primarily eat plant material. They do not possess a sting. Adult females instead have a saw-like ovipositor that looks like a sting. They use that ovipositor to cut into plant tissues, where they then lay their eggs. Those eggs will hatch, emerge from the plant, and begin to search around for plant material to eat. Eventually they will molt, pupate and turn into adult wasps through a metamorphosis similar to butterflies. Unlike most other wasps they do not have a pinched waist and have an overall “stockier,” more fly-like appearance.

Four images of wasps collaged together with the text Parasitica (Parasitic Wasps) overlaying the photos in the center. In the lower right corner overlaying text says, "*No sting! Has long-like ovipositor."

The other major stingless wasp lineage is the Parasitica, this massive and diverse group is commonly referred to as the parasitic wasps. There are many species in this group that are undescribed, that science knows virtually nothing about. With some exceptions, species of Parasitica are primarily parasites of other arthropods, chiefly terrorizing the larvae of butterflies, moths, beetles and even other wasps. Most have immobile larvae that develop inside the body of a host. Yes, you read that right…inside the body. Where they develop and eventually kill the host upon emergence. These wasps have a pinched waist that is hypothesized to have evolved so adult females could more easily articulate their long ovipositors (up to 2-3 inches long in the genus Megarhyssa). They use their long ovipositor to detect and probe for their soft bodied hosts that are found in otherwise hard to reach places. Not only can Parasitica lay eggs with their ovipositor, but some species can also inject a specialized immunosuppressing venom that allows their parasitic larvae to feed without harassment from their hosts pesky immune system. Parasitica is undoubtably one of the most important groups of insects when it comes to suppressing populations of insects that eat plants. Without these parasites keeping the insect herbivores of the world in check, there wouldn’t be many leafy greens left over for us mammals to eat.

Six images of wasps collaged together with the text Solitary Aculeata (Non-bee, prey-hunting wasps) overlaying the photos in the center. In the lower right corner overlaying text says, "*May have a sting! But will NOT show aggression."

That leaves us with the last major group of wasps: Aculeata. This group is otherwise referred to as the “stinging wasps”. The ovipositor of Aculeata has totally lost the function of egg laying and is only used for injecting specialized venom into prey or predators. They show a shocking diversity of behavior with 90 percent being solitary, nest provisioning species. Solitary wasps do not form hives and individually store food in a pre-selected cavity OR carefully made structure for their young. After mating, female’s meticulously search for or construct a nest that will safely carry their developing young through the cold winter months. Once a nest site is chosen or built, these industrious mothers will stock it with a food item that is specific to their species. Food items taken range across most insect orders and in some cases even extend to pollen from plants (for example in the bee lineage of Aculeata). Solitary wasps that hunt other insects use their specialized venom to subdue and paralyze their prey. Once paralyzed they carry their prey item back to their nest and lay an egg on it. The egg will hatch, the larvae will eat the prey, develop/pupate, and then emerge as an adult the following year on an environmental cue. The mother that did all that hard work will die in the winter months, never to see their young emerge. Now that’s a parental investment! Since the sting of solitary wasp species is so specialized to paralyze their specific arthropod prey and mother wasps spend so much energy on construction and provisioning their own nests, they will hardly ever stop to sting a mammal. But even if you do somehow end up on the stinger end of a solitary wasp, the venom that is used to paralyze other insects typically doesn’t contain the chemical composition to cause pain in mammals. Rendering the sting of these solitary wasps completely harmless.

Four images of wasps collaged together with the text Social Aculeata (Hornets, Yellow Jackets, Honey Bees, Ants, etc...) overlaying the photos in the center. In the lower right corner overlaying text says, "*May have a sting! Some species will be aggressive if provoked."

The stinging wasps with a capacity to cause pain in mammals are primarily the lineages of Aculeata that have developed a social lifestyle. Out of the around 60,000 some species of stinging wasps only a few thousand have developed a social lifestyle. Social wasps include things like ants, hornets, paper wasps, and the social bees (such as honeybees and bumblebees) and build hives that contain a queen and different castes of workers that perform various tasks. This division of labor permits them the ability to raise many more young than their solitary counterparts. Throughout the year they can collect and store massive amounts of food resources in their hive. Full of food resources and juicy protein rich larvae, these hives happen to be a perfectly convenient snack for the many foraging vertebrates that have existed over evolutionary history. To deal with this situation, many hive forming wasps have developed a venom painful enough to ward off vertebrate predators and a social caste of aggressive guards to protect the resources of the hive. Unfortunately for us, many of these social species build their hives in dry places like under rocks, cliffs, and inside trees, places that our modern housing structures tend to mimic fairly well. Hence, the paper wasp nests in your backyard shed and the beehive in the walls of your house. It’s important to remember these wasps are the exception to the trend of wasp lifestyles, and that we should build our skills to be able to detect and respect social wasps and discern these from the harmless solitary species that are essential to a maintaining a healthy environment.

Six images of wasps collaged together with the text Solitary Aculeata (Bees, pollen collecting wasps) overlaying the photos in the center. In the lower right corner overlaying text says, "*May have a sting! But will NOT show aggression."

I believe our fear of wasps stems from the trunk of a larger issue. Our modern education system fails to encourage respect for our local ecosystems. We therefore live most of our lives divorced from the non-human mystery of life on earth. From plants, to insects, all the way to vertebrates (especially snakes), we are unable to discern between harmful and harmless species because we haven’t been given to tools to do so. The few interactions we have with wasps are with the aggressive social species that live in close proximity to our human-made worlds. We’re stung once as children, and for the rest of our lives we write off all things that remotely look like wasps as being disposable. In the same stride of logic, we level habitat in mass and displace life for frivolous profits before we can even comprehend what is being lost.

For these reasons, I swear there is a magic inside reconnecting with wasps. Next time you see a wasp, I beckon you turn your attention away from fear and ask, “what is that wasp doing…and why?”. Follow her for a bit. Watch intently and observe her behaviors. I guarantee to you that if you develop this as a practice, entire worlds that were previously invisible will begin to appear on the landscape. With every human-wasp interaction that comes from a place of curiosity and not fear, more and more meaning will be restored from the non-human mystery back into to our human-centric worlds.

Josh Klostermann is a student of botany (plants) and melittology (wild bees) with the goal of being a regional expert in these fields. His current research is focused on the effects of landscape disturbances and restoration on bee and wasp communities. He is an avid wildlife photographer and all-around bug nut.

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