When an insect with yellow and black stripes buzzes past, most people assume they are seeing a bee. This is often incorrect, as the insect world is full of harmless species that have evolved to look exactly like stinging bees and wasps. This protective deception is known as mimicry, allowing non-defensive insects to deter predators who have learned to avoid the painful sting of a true bee. Understanding the features and behaviors of these common bee look-alikes is the first step in accurately identifying the insects visiting your garden.
The Strategy of Mimicry
The appearance of these insects is an excellent example of Batesian mimicry, a defensive strategy where a harmless species copies the warning signals of a dangerous one. True bees and wasps possess aposematism, the bright coloration that advertises their ability to sting or their unpleasant taste. Predators quickly learn to associate the striped pattern with a painful experience, and they subsequently avoid any insect bearing that pattern.
Insects that do not have a stinger gain a survival advantage by evolving to visually imitate the armed model. This mimicry is effective because the predator’s learned aversion to the bee is transferred to the non-stinging look-alike. The result is a diverse array of imposters that look convincingly like their stinging counterparts, gaining protection without needing physical defenses.
Key Identification Features
The most common bee imposters are true flies (Order Diptera). A few simple anatomical differences can help distinguish them from true bees (Order Hymenoptera).
Bees have two pairs of wings, totaling four, which often overlap or fold flat over the abdomen when resting. Flies, in contrast, possess only one pair of functional wings, with the second pair reduced to small, club-like structures used for balance.
Observing the insect’s head also provides clear clues. Bees typically have long, visible antennae that are often elbowed or bent at a joint. Flies, in contrast, usually have short, stubby, or nearly invisible antennae.
Flies also tend to have large, prominent compound eyes that cover a significant portion of their head, often meeting near the top. Bees have smaller, oval-shaped eyes positioned more to the sides of their head. Finally, most bees have a distinct constriction or narrow waist between the thorax and abdomen, while most flies have a stout, continuous body shape.
Common Bee Imposters
The most frequently encountered bee mimics belong to the family Syrphidae, commonly known as hoverflies or flower flies. These insects are masters of flight, known for their ability to hover nearly motionless before darting quickly to a different location. Hoverflies have prominent black and yellow or orange abdominal banding, but their short antennae and single pair of wings confirm they are flies.
Adult hoverflies are beneficial pollinators, and their larvae are highly valued in gardens because they feed voraciously on soft-bodied pests like aphids. Another group of mimics are the bee flies (Family Bombyliidae), which often have dense, fuzzy hair that makes them look like small, round bumblebees. A defining feature of many bee fly species is a long, rigid proboscis that extends prominently forward from the head, used for feeding while hovering over flowers.
Bee flies exhibit an erratic, jerky flight pattern and are harmless, as they lack stingers. Their life cycle includes a dark side, however, as their larvae are parasitoids that develop inside the nests of true bees. Less common, but sophisticated mimics, are certain types of clearwing moths (Family Sesiidae).
These moths fly during the day and have large, clear patches on their wings, which is unusual for moths. Some species have tufts of scales on their legs that look similar to the pollen baskets found on the hind legs of some bees. Clearwing moths often engage in behavioral and acoustic mimicry, flying with a zigzag trajectory and generating a buzzing sound nearly identical to that of their bee models.