Cicada killer wasps are large, imposing insects. Known scientifically as Sphecius speciosus, they can measure up to two inches, making them among North America’s largest wasps. They display black or dark brown bodies with vibrant yellow stripes, reddish or orangish legs, and brownish wings. This combination of size and color can lead to them being mistaken for other, more aggressive stinging insects like hornets or yellowjackets.
The Solitary Nature of Cicada Killer Nests
Cicada killer wasps are solitary insects; each female constructs and provisions her nest independently. Unlike social insects such as honey bees or yellowjackets, they have no queen or worker caste and do not form communal colonies. A single female is responsible for all nest aspects, from digging to hunting prey and laying eggs.
While each nest belongs to an individual female, multiple cicada killers often nest in close proximity. This occurs because well-drained, sandy soil exposed to full sunlight is desirable for nesting. Such aggregations can give the impression of a colony, with dozens or even hundreds of individual burrows in a concentrated area. However, even within these dense groupings, each female operates autonomously, maintaining her own separate tunnel system and raising offspring independently.
Nesting Habits and Behavior
Nesting begins with the excavation of a burrow, typically in loose soil or sandy areas. These tunnels can extend 12 to 18 inches deep and 36 to 70 inches long, often with a U-shaped soil mound at the entrance. Inside, the female creates several individual cells, or chambers, serving as nurseries for her young. A single burrow can contain four to five cells, sometimes up to 10 or more, with some females rearing up to 16 larvae within one system.
Once a cell is prepared, the female hunts for cicadas. She locates a cicada, often in trees, and stings it to inject venom, paralyzing but not killing it. The paralyzed cicada, which can be heavier than the wasp, is dragged or flown back to the burrow and placed into a cell. An egg is laid on the paralyzed cicada, usually at the base of its middle leg, and the cell is sealed with soil.
Male eggs are provisioned with one cicada; female eggs, requiring more sustenance due to their larger size, receive two or three. The egg hatches within one to three days, and the developing larva feeds on the still-living cicada for about two weeks, consuming it until only the outer shell remains. The larva spins a cocoon, overwinters in the burrow, pupates in spring, and emerges as an adult the following summer.
Cicada Killers in the Landscape
Cicada killers play a role in their ecosystem by regulating cicada populations. Adult cicadas can damage trees by laying eggs in branches, so the wasps’ predatory behavior benefits deciduous trees. Beyond predation, adult cicada killers also contribute to pollination by feeding on flower nectar and plant sap.
These large wasps are not aggressive towards humans and rarely sting unless provoked or mishandled. Female cicada killers possess a stinger, primarily for paralyzing cicada prey, not for defense against humans. Male cicada killers, though intimidating due to their territorial “dive-bombing” behavior, do not have a stinger and cannot sting. Their presence in residential areas is linked to available loose, well-drained soil for nesting and nearby cicada populations, their primary food source.