Cicadas are large insects recognized globally for their loud, buzzing presence during the warmer months of the year. Their seasonal appearance and characteristic sound make them a familiar part of the summer landscape. People often wonder whether this chorus continues throughout the night or if these creatures follow a specific daily rhythm.
The Direct Answer: Diurnal Activity
Cicadas are overwhelmingly diurnal, meaning their period of activity is concentrated during the daylight hours. As ectotherms, these insects rely heavily on external environmental heat to power their biological functions, including movement, flying, and singing. Their activity level is directly tied to temperature, with most species requiring their body temperature to be near 72°F for full functionality.
This dependence on warmth means that peak activity often coincides with the hottest parts of the day, typically from late morning through late afternoon. The warmth enhances their metabolic rate, which is necessary for sound production. While some species may emerge from the soil at dusk to avoid visual predators, mature adults remain strongly diurnal for the remainder of their short lives.
Behavior During Peak Activity
Sound production is the cicada’s primary daytime activity, serving the purpose of mate attraction and communication. This sound is created by males using specialized organs called tymbals, which are paired, ribbed membranes located on the side of the abdomen. Tiny muscles rapidly contract and relax, buckling the tymbal membrane inward and outward hundreds of times per second.
This rapid vibration creates a continuous, high-volume sound that can reach over 90 decibels in large choruses. The primary function of this “singing” is to produce a congregational song that establishes territory and attracts females. Once a female is nearby, the male switches to a courtship call, and females signal acceptance by flicking their wings. Males may also produce a distinct alarm call, often a squawk, if disturbed or captured by a predator.
What Happens at Night
As the sun sets and light levels decrease, the cicada chorus generally stops. The main reason for this cessation is the drop in ambient temperature, which falls below the threshold required for sustained activity. The minimum functional temperature for flying and singing for many species is between 65°F and 70°F.
When temperatures cool, cicadas enter a resting state, becoming immobile and clinging to tree bark or vegetation. This inactivity minimizes energy expenditure during cooler hours. While some individuals may utter short bursts of sound on unusually hot nights or near bright artificial lights, purposeful activities like flying or continuous singing cease. The sounds heard after dark are most often produced by truly nocturnal insects, such as crickets and katydids.