Insects resembling bees are common, often causing confusion. This mimicry, where harmless insects adopt the appearance of potentially dangerous ones, is an evolutionary strategy. This article explains why mimicry occurs and how to distinguish true bees from their look-alikes.
Why Insects Mimic Bees
Batesian mimicry is an evolutionary strategy where a harmless species imitates the warning signals of a harmful one. Predators learn to avoid insects with warning coloration, like the black and yellow patterns of many bees, due to their painful stings. By copying these features, non-stinging insects deter threats, allowing them to survive more effectively.
Key Features to Differentiate Them
Distinguishing true bees from their mimics involves observing several physical characteristics and behaviors.
Antennae
Bees have short, elbowed antennae, typically with 12-13 segments. Many mimics, especially flies, have shorter, stubbier, unsegmented antennae that appear bristle-like.
Wings
Bees have four wings, two on each side, often coupled during flight and usually clear. Many mimics, particularly flies, possess only two wings, which may be broader or patterned.
Eyes
Flies, including many bee mimics, often have large compound eyes covering much of their head. Bees generally have smaller, more widely spaced eyes on the sides of their heads.
Body Shape and Hairiness
Bees often have robust, hairy bodies, especially on their thorax and abdomen, aiding pollen collection. Many mimics, like hoverflies, have smoother, more streamlined bodies with less dense hair.
Flight Patterns
Bees typically display direct, purposeful flight paths. Many mimics, especially hoverflies and bee flies, can hover in mid-air, darting quickly before resuming a stationary position.
Common Bee Mimics and Their Traits
Several insect groups have evolved striking resemblances to bees, each with distinct features that help differentiate them.
Hoverflies (family Syrphidae)
Hoverflies are convincing mimics due to their yellow and black banding. As true flies, they have only two wings and short, stubby antennae. Many hoverflies also hover in place, a flight characteristic less common in bees. Their bodies are smoother and less hairy than true bees.
Bee Flies (family Bombyliidae)
Bee Flies are true flies that imitate bees. They have two wings, often with distinctive patterns. A prominent feature is their long, slender proboscis, used for feeding on nectar while hovering. Though their bodies can be hairy, their unique proboscis and single pair of wings distinguish them.
Certain Moths
Certain Moths, such as Bee Hawk-moths (Hemaris), mimic bees. Active during the day, they have stout, hairy bodies. While they possess two pairs of wings like bees, their wings often have transparent patches. Their antennae are typically thicker and clubbed, differing from a bee’s. Bee hawk-moths feed while flying and are more agile than the bumblebees they resemble.
Some Beetles
Some Beetles, including Flower Longhorn Beetles (Typocerus species), mimic bees or wasps. These beetles have hard wing cases (elytra) covering their flight wings, absent in bees. Their bodies are generally more elongated and cylindrical. While they may exhibit yellow and black patterns, their overall structure and elytra are clear differentiators. Their antennae are notably long, often exceeding their body length.
The Ecological Role of Mimics
Beyond their deceptive appearances, many bee mimics contribute valuable ecological services. Hoverflies are important pollinators and their larvae are significant predators of garden pests like aphids. Bee flies also function as pollinators. These mimics perform distinct and beneficial roles in maintaining biodiversity and ecosystem health.