Wasps: Friend or Foe?

As summer begins, you may be on the lookout for your least favorite outdoor picnic guest: the wasp. Wasps don’t have the best reputation, and much of it is due to a lack of understanding. However, wasps are important pollinators and pest control agents and even help produce food items we enjoy!  Wasps and bees are both members of the order Hymenoptera. They often get confused for one another, which is no surprise considering that bees evolved from wasps 120 million years ago. Wasps began as carnivorous invertebrates that fed on other insects. Over time, some wasps began consuming pollen as a food source. Those that used pollen as a source of energy evolved into bees and diversified quickly. Melittosphex burmensis is one of the first transitionary forms between bees and wasps. Melitta is a form of the Greek word for “honey bee,” and Sphex translates to “wasp.” Although wasps and bees have a shared lineage, there are some key differences between the two. Bees are known for being round and fuzzy, while wasps are slender and, for the most part, hairless.    There are three common types of wasp species: social, solitary, and parasitoid. You may be most familiar with yellowjackets, hornets, and paper wasps. These are all examples of social wasp species. Like bees and ants, they have a queen and many other workers that carry out the daily operations of the colony. Social wasps have an allegiance to their hive and often try to hide their homes for protection. For this reason, we often stumble upon wasp nests by accident, which can lead to an unpleasant experience for both us and the wasps.  Hornet and paper wasps create hives by chewing up wood and plant fibers to make a paper-like material. Paper wasp nests are cone-like and hang from a singular stem. They typically build nests on roof overhangs to avoid rain and predators. Hornets build spherical and large paper nests high in trees to avoid predation, and yellow jackets build their colonies underground. Yellow jackets, in particular, are scavengers, meaning they eat almost anything. Regularly emptying your outdoor trash receptacles and using trash cans with closing lids can keep them away.  Another way to deter wasps is to keep peppermint oil handy; they avoid this scent. If a nest was removed from your property, clean the area with peppermint oil to prevent another colony from moving in.   Are wasps good for anything besides stinging? Yes, wasps are pollinators, just like their bee relatives! Wasp diets vary depending on the species, but most wasps eat other insects as larvae and feed on sugar as adults. Unlike bees, wasps do not have a proboscis to sip up nectar; they have mouthparts for chewing food for their young. For this reason, wasps typically visit flowers that make nectar easily accessible. In the process, they end up picking pollen and dispersing it. A good way to benefit from wasp pollination and avoid unwanted encounters is to have flowering plants at least 6 inches away from areas where people frequent.     Other wasp species have a mutualistic relationship with the plants they use as food sources. About 1,000 species of fig trees depend on fig wasps for reproduction. Fig trees have no outer flowers for pollination; they have tiny flowers inside their fruit that carry pollen. A female fig wasp will burrow into a fig to lay her eggs, and after laying the eggs, she dies inside the fig. The wasp larvae grow inside of the fig fruit, collecting pollen in the process. Male fig wasps are small and wingless, while females are large with wings. Males mate with females inside the fig and then die. Then, the fertilized females move out to find a fig to lay their eggs in. Once they enter the fig, they disperse pollen, and the cycle repeats. But don’t worry, you aren’t eating wasps when you take a bite out of a fig. Figs have an enzyme that completely breaks down and digests wasps inside of them before ripening for eating.     Wasps also help with pest control. Every tomato gardener’s worst nightmare is a tomato hornworm. Tomato hornworms are the caterpillar form of the Five-spot hawk moth (Manduca quinquemaculata), and their favorite food is your tomato crops. Wasps often hunt caterpillars for food and help keep their populations in check. Caterpillars are good to have in your garden because they will grow to become pollinators, but too many caterpillars could lead to garden destruction. The Mexican Honey Wasp (Brachygastra mellifica) is a triple threat—in a good way. It helps pollinate avocados, controls pest species, and is one of the few wasp species that produces honey!  Understanding the diversity of wasp species and what they contribute to our planet can help us better appreciate these misunderstood invertebrates. Most wasp species pose no stinging threat, and easy ways to coexist with wasp species that do sting. Cultivating biodiversity in our gardens welcomes predator and parasitoid species like wasps that help keep the pest populations low and pollination rates high. 

Written by Celena Romero