Wasps are a familiar sight, often raising questions about their ability to see after sunset. Understanding their vision helps comprehend their activity patterns. This article explores the mechanics of wasp vision and their activities in low light.
How Wasps See
Wasps possess compound eyes, a visual system common among insects. These eyes are composed of numerous individual light-sensing units called ommatidia, each acting like a tiny, independent lens. This structure provides wasps with a wide field of view and makes them highly effective at detecting movement. Wasps also have three smaller simple eyes, called ocelli, between their compound eyes, which help them sense light and dark.
Wasps can see colors in the ultraviolet (UV) spectrum, beyond human perception. While they have poor red-end vision, perceiving it as dark or black, they effectively see blue, green, and UV light. This ability to detect UV patterns is useful for locating nectar sources on flowers, which often display UV markings invisible to the human eye. Their compound eyes’ mosaic-like image and motion detection capabilities aid them in foraging and navigating during daylight.
Wasps and Low Light Vision
Most common wasp species are primarily diurnal, active during the day. Their compound eyes, well-suited for bright conditions, are not designed for clear vision in low light. The individual ommatidia, which create a mosaic image, are limited in their ability to gather sufficient light as darkness increases. This structural limitation results in very poor detailed vision for these wasps at night.
While some specialized nocturnal wasp species exist, most common wasps do not possess true night vision. They might perceive extreme shifts in light and dark, but they lack the resolution and sensitivity required for complex navigation or foraging in the absence of significant light. Their visual system prioritizes motion detection and broad light perception over detailed image formation in dim conditions.
Wasp Activities at Night
When darkness descends, most common wasps cease foraging, hunting, and other activities due to their limited night vision. They generally return to their nests to rest and remain inactive until daylight. This period of inactivity is not sleep in the mammalian sense, but a state of reduced activity where they are still alert to disturbances.
Inside the nest, wasps may continue duties like caring for larvae or performing minor repairs. If a nest is disturbed at night, wasps may still react defensively, but their overall activity levels outside the nest are minimal compared to their daytime routines. Their reduced activity at night is a primary reason why pest control professionals often recommend treating wasp nests after dark, as most of the colony is present and less active.