The cicada killer wasp (Sphecius speciosus) is a large, solitary insect known for its impressive size, with females often reaching nearly two inches in length. The female exclusively hunts and paralyzes cicadas to provision her subterranean nest, providing a food source for her developing larva. Locating these ground nests requires understanding the wasp’s behavior and recognizing specific environmental cues. This guide details the physical signs of the burrow and the preferred nesting habitats.
Key Signs of Cicada Killer Activity
The presence and movement of adult wasps during the summer months, typically between July and September, indicate a nest’s proximity. Females fly low to the ground, skimming over the lawn or bare soil as they search for suitable burrowing locations or return to an established nest. Males exhibit highly territorial behavior, often flying erratically or hovering near one another as they aggressively defend the nesting area.
The most definitive sign of an active nest is seeing a female transporting her prey. After stinging a cicada with venom that induces paralysis, the female drags the immobilized insect back to her burrow. This often involves the female laboriously dragging the cicada across the ground or carrying it up a tree to gain altitude for a gliding flight toward the nest entrance.
The Anatomy of a Cicada Killer Burrow
The physical characteristics of the burrow entrance offer the most reliable identification. The main tunnel opening is nearly circular, measuring approximately 0.5 to 1.5 inches in diameter, reflecting the robust size of the female wasp. This opening leads to a tunnel that can extend 10 to 20 inches deep into the soil, sometimes reaching lengths of up to 70 inches before branching into individual nesting cells.
The most defining feature is the mound of loose soil piled immediately around the entrance. As the female digs, she uses specialized spines on her hind legs to push the excavated material behind her, creating a distinctive U-shaped or crescent-shaped pile of fine, granular dirt. Each cicada killer female typically digs her own burrow and provisions her own cells, though multiple solitary females may choose to nest in close proximity.
Optimal Environments for Nesting
Cicada killers prefer loose, well-drained, and light-textured soil, which may include sandy or silty compositions. They actively avoid compacted or heavily saturated ground, as it makes excavation difficult and risks the integrity of the underground cells.
The wasps also exhibit a strong preference for nesting sites that receive full sun exposure and have sparse vegetation. Common locations for these burrows include sparse patches within lawns, sand-based golf course bunkers, flower beds, and the edges of concrete structures. The soil along sidewalks, patios, and embankments often meets the requirements for dryness and easy digging, making these areas prime spots to focus the search.