Hoverflies (family Syrphidae) are familiar insects often seen in gardens, identified by their striking yellow and black stripes. This coloration closely resembles wasps and bees, leading people to mistakenly believe they can bite or sting. Understanding the true nature of this common garden visitor requires clarifying its anatomy.
The Direct Answer: Do They Bite or Sting?
Hoverflies are completely harmless to humans and cannot bite or sting. They are true flies (order Diptera), meaning they are anatomically incapable of delivering a sting. The stinging mechanism in insects like wasps and bees is a modified ovipositor, a structure absent in the Diptera order. The adult hoverfly also lacks the mouthparts necessary to bite defensively, as its mouth structure is adapted only for lapping up nectar and pollen.
Telling the Difference: Hoverflies vs. Wasps and Bees
Distinguishing a hoverfly from a stinging insect requires observing specific physical characteristics. The most reliable differentiator is the number of wings: hoverflies, like all true flies, have only two visible wings, while bees and wasps (order Hymenoptera) have four wings. Hoverflies also possess a different body structure and antennae compared to their stinging counterparts. Wasps typically have a distinct, narrow “waist,” or petiole, connecting the thorax and abdomen, a feature the hoverfly lacks, often having a broader, flatter body. Furthermore, hoverflies have short, stubby antennae, contrasting sharply with the longer, segmented antennae seen on many wasps and bees.
Why They Are Important to the Ecosystem
The hoverfly plays a dual role in supporting natural and cultivated ecosystems. As adults, they are important secondary pollinators, moving between flowers to feed on nectar and pollen necessary for egg development. Their activity as pollinators is noteworthy during cooler parts of the season, often making them among the first insects to emerge in spring and the last working in the fall.
The larvae of many hoverfly species are effective predators of soft-bodied garden pests. A single larva can consume hundreds of aphids, thrips, or mealybugs during its development. Female hoverflies lay their eggs directly onto infested plants, ensuring their young have an immediate food source upon hatching. This predatory behavior makes the hoverfly a valuable natural control agent for managing pest populations without chemical insecticides.