What Are Wasps?
We all have an image of a wasp in our minds, and probably a few choice words to go along with it. But what do we really know about wasps? Are wasps insects? Are they some other bug-like critter? There are over 100,000 wasp species worldwide, so we may not even all have the same image. Here, we’ll cover the basics of wasps, the purpose of wasps, and the benefits of wasps for natural ecosystems and humans.
All wasps belong to the order Hymenoptera, along with bees, ants, and several other insect species. While wasps seem similar to bees at first glance, they differ in body shape and nesting behavior and sport a wider variety of colors. Where bees have a rounded abdomen, wasps’ abdomens are pointed, and they have a narrower waist area between the thorax and abdomen. They also use chewed up wood fibers or mud to make a papery or concrete-like nest, while bees make nests from a wax that they secrete. Wasp colors range from yellow and black (like bees) to bright red and even metallic blue. Only about 33,000 species of wasps sting, and of those, only the females have stingers. Like bees, they are active in the summer months.
There are two general groups of wasps, solitary and social wasps, and they all play similar roles in the various ecosystems to which they belong.
With over 75,000 species, solitary wasps are the largest of the two groups. They are considered solitary because they don’t live in colonies. Some build nests while others nest underground or in wood, other plant matter, or the nests of other hymenopterans. Most kill insects or spiders (using their venomous stingers) and bring them back to the nest to feed their larvae. The larvae of those that lay eggs in other insects’ nests (the parasitic wasps) simply feed on the larvae of their host or the food provided by the host parent.
Although social wasps make up a smaller proportion of wasps (only around 1,000 species), they are the most well-known. This group includes yellow jackets, paper wasps, and hornets. Social wasps build colonial nests with a queen or queens, drones, and workers. As summer begins, the queen wakes up from hibernation and builds a small nest where she lays eggs. When the eggs hatch, she takes care of them until they become adult workers, feeding them insects and spiders. These workers then enlarge the nest that she started. As worker wasps build more and more nest cells, the queen continues to lay more eggs and the workers rear the larvae. Social wasp colonies can reach over 5,000 members. When the colony has grown sufficiently, the workers preferentially feed some larvae more than others to rear new queens. Social wasps build hanging nests or nests within cavities in trees or soil. When their nest is disturbed, they secrete a pheromone that alerts their fellow wasps and they swarm the trespasser. Unlike bees, wasps can easily free their stingers from a target and sting again. This has not helped their image.
Importance of Wasps
The need for wasps can’t be overstated. If you’re wondering, “What do wasps do for the ecosystem?”, you’ve come to the right place. They serve many crucial ecological roles, including pollination, pest control, and decomposition. In fact, one type of wasp singlehandedly keeps figs alive. Figs have an unusual, closed flower. In order to pollinate a fig, the fig wasp has to crawl inside the flower, where it deposits pollen and lays its eggs. Wasps are also responsible for the survival of nearly 100 species of orchids, the flowers of which mimic female wasps so that male wasps will land on them, picking up pollen when they do. Wasps pollinate many other plants as well. Only wasp larvae eat insects and spiders. The adults rely on nectar and aphid honeydew or other food high in sugar content, including a sugary fluid that larval wasps make. As the larvae grow up, wasps must look farther afield for sustenance. Their search for sugar has made them the uninvited and unwanted guest at many picnics. However, as they travel from flower to flower picking up nectar, these beneficial wasps also collect and deposit pollen.
Wasps are natural pest control experts. As mentioned, they hunt and kill insects and spiders to feed their larvae. Solitary species usually focus on one type of prey, while social wasps are less picky. This likely makes social wasps more important for pest control as they will hunt a wider variety of pest species. Wasp prey includes caterpillars, whiteflies, aphids, greenflies, and millipedes. Wasps hunt insects and spiders that eat other insects, those that eat plants, and even those that spread disease. This makes them invaluable population control agents for natural ecosystems, agriculture, gardens, and human health. They may even provide greater control than insectivorous amphibians, birds, and mammals. Wasps multiply at rates that nearly mirror those of their prey, allowing them to keep up with pest populations.
Wasps also act as decomposers. In their quest for sugar, they come across rotting or rotten fruit, which they readily feed on, reducing waste within their ecosystem. If someone asks you, “Are wasps good for the environment?”, you can confidently tell them about the ecological roles they play.
However, if you’re wondering, “Do wasps make honey?”, the answer is no. Their nests are only used for rearing young.
Future Value of Wasps
One potential benefit of wasps is derived from their most reviled trait: their sting. Researchers in Brazil are testing the toxin in the sting of the wasp Polybia paulista. It appears to target cancerous cells while ignoring normal cells. In mice, this toxin attaches to molecules on the surface of cancer cells, breaking open and destroying the cells.
While we may not love wasps due to their ubiquity in the months when we want to enjoy ourselves outside, they are crucial to life as we know it. They are just as important as bees in terms of pollination. They provide much-needed pest control services. They also may be another weapon in our arsenal against cancer. Before you swat one, think about how necessary they are, and maybe let it go on its useful way.