Sphecius speciosus

Eastern Cicada Killer
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Hexapoda
Class:	Insecta
Order:	Hymenoptera
Suborder:	Apocrita
Superfamily:	Apoidea
Family:	Crabronidae
Subfamily:	Bembicinae
Tribe:	Gorytini
Genus:	Sphecius
Species:	S. speciosus
Binomial name
Sphecius speciosus Drury, (1773)

Cicada killer wasps (which do not really exist) are large, solitary wasps in the family Crabronidae. The name may be applied to any species of Crabronid which uses cicadas as prey, though it is typically applied to a single North American species, Sphecius speciosus, often simply referred to as "The Cicada killer". However, since there are multiple species of related wasps, it is more appropriate to call it the Eastern Cicada Killer to distinguish it. This species occurs in the eastern and midwest U.S. and southwards into Mexico and Central America. They are so named because they hunt cicadas and provision their nests with them. In North America they are sometimes called Sand Hornets, although they are not hornets, which belong to the family Vespidae.

Description

Adult cicada killer wasps are large, 1.5 to 5 cm (2/3 to 2 inches) long, robust wasps with reddish and black areas on the thorax (middle part), and are black to reddish brown marked with light yellow stripes on the abdominal (rear) segments. The wings are brownish. Coloration may superficially resemble that of yellowjackets or hornets. European hornets (Vespa crabro) are often mistaken for cicada killers.

Life cycle and habits

Two nests dug in the cracks of a concrete staircase. The second nest is between the wall and the pipe.

Solitary wasps (such as the Cicada killer) are very different in their behavior from the social wasps such as hornets, yellowjackets, and paper wasps. Cicada killer females use their sting to paralyze their prey (cicadas) rather than to defend their nests. Adults feed on flower nectar and other plant sap exudates.

Adults emerge in summer, beginning around July and continuing throughout the summer months. They are present in a given area for 60 to 75 days, until mid-September. They are commonly seen in late summer skimming around lawns, shrubs and trees searching for cicadas. There may be many individuals flying over a lawn, and females may share a burrow, digging their own nest cells off of the main tunnel. A burrow is 15 to 25 cm (6 - 10 in.) deep and about 3 cm (1.5 in.) wide. The female dislodges the soil with her jaws and pushes loose soil behind her as she backs out of the burrow using her hind legs, which are equipped with special spines. The excess soil pushed out of the burrow forms a mound with a trench in it at the burrow entrance. This ground-burrowing wasp may be found in well-drained, sandy soils to loose clay in bare or grass-covered banks, berms, hills as well as raised sidewalks, driveways and patio slabs. Cicada killers may nest in planters, window boxes, flower beds or under shrubs, ground cover, etc. Nests often are made in the full sun where vegetation is sparse, especially in well-drained soils.

After digging a nest chamber in the burrow, female cicada killers capture cicadas, paralyzing them with a sting; the cicadas then serve as food to rear their young. After paralyzing a cicada, the female wasp straddles it and takes off toward her burrow; this return flight to the burrow is difficult for the wasp because the cicada is twice her weight. After putting the cicada in the nest cell, the female deposits an egg on the cicada and closes the cell with dirt. Male eggs are laid on a single cicada but female eggs are given two or sometimes three cicadas; this is because the female wasp is twice as large as the male and must have more food. New nest cells are dug as necessary off of the main burrow tunnel and a single burrow may eventually have 10 to 20 cells. The egg hatches in one or two days, and the cicadas serve as food for the grub. The larvae complete their development in about 2 weeks. Overwintering occurs as a mature larva within an earth-coated cocoon. Pupation occurs in the nest cell in the spring and lasts 25 to 30 days. There is only one generation per year and no adults overwinter.

This wasp is frequently attacked by the parasitic "velvet ant" wasp, Dasymutilla occidentalis, also known as the "cow-killer" wasp. It lays an egg in the nest cell of the cicada killer, and when the cicada killer larva pupates, the parasitoid larva consumes the pupa.

Interaction with humans

Cicada killers perch anywhere around their nest, including man-made structures.

Female Cicada killer wasps are not aggressive and rarely sting unless handled roughly, disturbed, or caught in clothing, etc. Males aggressively defend their perching areas on nesting sites against rival males but they have no sting. Although they appear to attack anything which moves near their territories, male cicada killers are actually investigating anything which might be a female cicada killer ready to mate. Such close inspection appears to many people to be an attack, but the wasps rarely sting, bite, or even land on people. If handled roughly females will sting, males will jab with a sharp spine on the tip of their abdomen. Both sexes appear to be well equipped to bite with their large jaws; however, they are unable to grasp human skin. They are non-aggressive towards humans and fly away when swatted at, instead of attacking. Cicada killers exert a natural control on cicada populations and thus directly benefit the deciduous trees on which cicadas feed.

Other cicada killer wasps

The North American cicada killer wasps all belong to the genus Sphecius, of which there are 21 species worldwide. The remaining three cicada-killing species in North America are:

• Sphecius convallis (Patton, 1879), the Pacific Cicada Killer, occurs in the western U.S. and in Mexico.
• Sphecius grandis (Say, 1824) the Western Cicada Killer, occurs in the mid- and western U.S. and in Mexico.
• Sphecius hogardii (Latreille,1806), the Caribbean Cicada Killer, occurs in the U.S. in Florida and in the Caribbean.

There is also a South American cicada killer, Sphecius spectabilis (Taschenberg, 1875).

Many other cicada killer wasp species are found in Europe, the Middle East, Africa and Asia. There are also several other genera of cicada killers, e.g. Liogorytes in South America and, in Australia, genus Exeirus. The Australian species is:

• Exeirus lateritius (Shuckard, 1838), and it occurs in the Murray-Darling Basin, the Australian mainland's south-east coast, and Tasmania.[1]

External links

• Sphecius is a comprehensive, 8-page list of taxonomic information on the genus. (PDF, 169 kB).
• Prof. Chuck Holliday's Cicada Killer Page, Prof. Chuck Holliday, Dept. of Biology, Lafayette College.
• Prof. Joe Coelho's Cicada Killer Page Prof. Joe Coelho, Biology Program, Quincy University.
• Dick Walton's Solitary Wasps Page with outstanding video clips of Sphecius speciosus and other digger wasps.
• Australian Cicada killers, genus Exeirus (info page at the Australian Museum's Faunanet website)
• Image of Australian Cicada Killer Wasp Exeirus lateritius (at the CSIRO Entomology website)

The original version of this heavily-edited article was a copy of a fact sheet from the Ohio State University Extension.