By Johnna Siegrist

Darke County Parks

Wasps are feared and detested all over the world, being known for their violent and painful stings. Like all living organisms, wasps serve a very important purpose. They serve an important role in natural pest control and as pollinators.

Without wasps, the world would most likely be overrun with spiders and other insects. Their feeding habits help keep the population of pests down. Wasps feed other invertebrates (animals that do not have a backbone, like insects, snails, spiders, and crayfish) to their larvae. Adult wasps, both social and solitary species, consume only sugars. This means their main food source is nectar and honeydew. Wasps will go from flower to flower looking for nectar to consume. They end up pollinating a large number of flowers because of their feeding habits. They will also consume honeydew, a waste product of aphids. Wasp larvae will also produce a sugary liquid that adults will sometimes consume.

So, what is the difference between social and solitary species? The main difference is their nesting behaviors. Social species will build nests and have bee-like colonies, including a queen. Queens are larger in size in comparison to the workers. They are larger in size because they are the sole member of the hive that lays eggs, therefore requiring more food than the rest of the members of the colony. The extra fat storage in queens ensures that they will survive winter, as most others (drones, workers, all solitary wasps) will not. Some species will build nests from paper that they make by chewing tree bark and then spitting back out. Social wasps will hunt spiders or insects and then carry pieces back to their nest to feed their larvae. Some species of social wasps are estimated to capture 14,000 tons of insects during the summer months. The dark paper wasp is a common example of a social wasp that can be found in Ohio. In solitary species, females live and breed on their own, never becoming part of a hive or colony. She will lay her eggs on the prey species, providing a food source for the larvae when they hatch. Spider wasps are known to hunt spiders for this purpose. They will paralyze a spider with their venom and then hide the immobilized spider. The wasp will then lay an egg on the spider, where the larvae will hatch and then feed on the spider. There are over 5,000 species of spider wasps. The rusty spider wasp is an example of a spider wasp that can be found in Ohio.

Wasps are often regarded as aggressive and are notorious for stinging multiple times, but oftentimes only sting when they feel threatened. Unlike bees, wasps do not lose their stingers when they sting something. There are only a few species in South America that will lose their stingers. Wasps’ stingers are relatively straight and smooth, which is how they can retain their stingers once they sting something. Honeybees have barbed stingers, which get stuck into the organism that they sting. When they try to pull their stinger out, it rips the stinger off of their bodies creating a hole that leads to their death. Male wasps do not have stingers, only females do. The stingers are a modified egg-laying organ called an ovipositor. Their stingers also possess a venom that they use to paralyze their prey. Wasp venom contains protein, which is what many people are allergic to. The venom also contains serotonin, histamine, and kinin. The histamine and kinin is what makes the sting so painful. Kinin helps slow muscle contracts, lowers blood pressure, and increases capillary absorption (increases water transportation). Each sting reduces the amount of venom that a wasp has stored. Once their reserve is empty, they will make more. Wasp venom also releases pheromones that will trigger other wasps’ aggression. This pheromone is the way that individual wasps call for backup, creating a swarm of wasps. Even solitary wasp species will call for backup using venom pheromones.

Many species of wasps are declining in population, but there has yet to be a species that has been listed as endangered. Much of this decline is due to climate change and habitat loss. As frustrating as wasp nests are, if possible do not remove them. Try to avoid using pesticides and other chemicals on wasps. They are harmful to both wasps and the surrounding environment, and other insects and plants often suffer as a result. The next time you see a wasp hanging around and are considering what to do with a nest, remember that they are important pollinators and help with pest control.