Neotibicen dorsatus

Description and identification

N. dorsatus is very distinct and beautifully colored and patterned species. Likewise, among other Neotibicen, this species has a head narrower than the rest of the body, a feature unique to this species. Another diagnostic trait is white pruinose spots lined vertically on the cicada's abdomen.

N. dorsatus adults have variable eye colors, but generally the eyes are leafy green, slate colored, blue-green, gray, olive oil colored, or sandy brown. The face of this species, like many other cicadas in the genus; has a distinctive black "mask" that extends from each of the cicada's bulging eyes. This species' pronotum is always a deep, rich caramel color. A large, black hour-glass shaped pronotal blotch extends vertically, but narrowly in the middle of the insect's pronotum.

Mesonotal patterning is similar to that of other members in this genus; with two pipe shaped marks resembling the Hebrew letter resh (ר) in the center. These are surrounded by other, smaller red, white, and tan colored markings and decorations, with varying degrees of color intensity in different individuals.

The Wings of N. dorsatus are transparent but always tinted "reddish" or amber colored. Wing veins are brown, and a smoky, pigmented black or amber "Z" shaped marking found in most members of this genus, is clearly present near the wing tips of N. dorsatus. Unlike other members in the genus however, the wing shape of this species is distinct, rounder and more circular than the wings of other species, which usually have narrower and pointed wing tips.

The venter of this cicada is lightly pruinosed. Opercula of the males are usually ochreous yellow with light powdering of pruinose. The legs are usually black, but tibia and terminal ends as well as joints may be yellow in some individuals.

Lastly, this species does not exhibit great amounts of regional variability compared with other members of this genus. Certain morphological characteritcis do vary slightly between individuals, but across the range of N. dorsatus, there is considrable consistency in morphological characteristics.

And, although uncommonly confused with other cicada species except the nearly identical and closely related N. tremulus, this species may be confused for a supercifally similar, but distantly related Neotibicen species: N. dealbatus. Certain overlapping diagnostic traits are found in both cicadas; such as the pruinose patterning on the abdomen and narrow head. This can complicate accurate identification or lead to erroneous reports, but the call of males and other morphological differences, coupled with geographic locations of both species are other factors that can aid in correct identification and separation of the two.

Distribution

Populations of N. dorsatus are located in central North America in the great plains region where habitat is favorable. This species is found East of the Rocky mountains and West of the Mississippi river. Although this species does not extend into Canada, its range may have extended to Canada prior to its decline.

N. dorsatus has been reported from the following states in the U.S.: Arkansas, Colorado, Idaho, Illinois, Iowa, Kansas, Missouri, Montana, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming.

Habitat

N. dorsatus is almost exclusively associated with tallgrass prairie and grassland ecosystems throughout the central United States. Adults are frequently found on bluestem grasses (Andropogon), goldenrod (Solidago), sumac (Rhus), sage (Artemisia), sunflower (Helianthus), ragweed (Ambrosia), boxelder (Acer negundo), cottonwoods (Populus), and willows (Salix), among other vascular plants. Adults rarely call or perch in tall trees, however, they can be found calling or feeding on trees adjacent to grassland environments. This species is absent in areas where the soil has recently been disturbed due to plowing or construction work or other human interference. In areas where soil has disturbed and the indigenous vegetation destroyed, another species of "prairie-inhabiting" Neotibicen that has greater tolerance to such environmental stresses and is opportunistic on colonizing plant species; N. auriferus, becomes more prominent and largely replaces N. dorsatus.

This species is not host specific and will be active normally on a broad range of miscellaneous vascular plants, grasses, and trees.

Although this cicada does not favor urbanized locations, in some circumstances it can be found calling from shrubs or small trees in residential areas. Sometimes, adult cicadas leave their perches at night and wander into lighted urbanized areas because they are attracted to UV lights (Phototaxis).

Nymphs are subterranean and feed on roots of trees and other plants.

Life cycle

As with all other annual cicada species, the complete life cycle of N. dorsatus is approximately 3–5 years long. Only males call to females during the day, preferably from grasses and shrubs in grassland ecosystems. The typical peak activity is from 10 a.m until 6 p.m, usually when the sun is bright and the ambient air temperature is warm. The call of the male is produced by a powerful muscle and membrane in the abdomen called a tymbal, which vibrates, contracts, and releases to produce the sound. The call is amplified because the abdomen of the insect is mostly hollow. Moreover, the calls of cicadas are species specific and the male calls are distinct, complex songs and phrases composed of a diverse array of clicks, buzzes, chirps, drones, chatters. The call of N. dorsatus in particular is a loud and steady, long, dry, rattle lasting for up to two minutes, making it much longer than the calls of other species in the genus Neotibicen.

Females communicate to males by clicking their wings, a signal that they are ready for mating. After mating, females lay eggs in dead branches of small trees or shrubs; using a ovipositor to slit branch and insert eggs. Later, the eggs hatch and nymphs drop to the soil and quickly burrow and feed on the roots of plants. There are five instars in which nymphs grow in size by shedding their skins underground. Once mature (after the 3-5 year feeding period underground), the nymphs emerge from the ground through tunnel systems during the summer. They crawl up trees, grasses, shrubs, buildings, or other stable structures and shed their final skin. At this stage they are teneral, but they will dry overnight and fly away by dawn to continue the cycle. Healthy adult cicadas of this species may live as long as a two months.

The dry, brown shells (exuviae) remain attached to plants and buildings.

Throughout most of the range, this species is active from July to September. Emergence and decline dates vary from year to year and from location to location.

Diet

Adults of N. dorsatus feed on numerous vascular plants by using their sucking, piercing mouthparts to reach the xylem of the plant and consume the fluids.

As nymphs, they feed on the roots of plants.

Natural predators

Cicadas have many predators because of their relatively few defenses. A multitude of mammals, birds, reptilians, and arthropods consume cicadas.

Cicada killer wasps frequently attack Neotibicen cicadas. The female wasp's keen eye scans trees and vegetation in search of prey. After locating a cicada, the wasp stings the cicada, injecting paralyzing venom. The wasp will then drag the paralyzed victim up a tree or post and fly away with it back to her nest. The cicada is buried in an underground burrow along with the wasp's eggs. The wasp's larvae emerge and feed on the living but paralyzed prey, pupate, and emerge the following spring. There is usually one generation of wasps a year.

There are also flies that are parasitoids of adult N. dorsatus, such as the parasitic flesh fly that specializes in N. dorstatus: Emblemasoma erro. The female flies have enlarged hearing structures used to detect the call of male cicadas. When a cicada is located the female lands on the host and deposits live larvae. The larvae burrow quickly into the cicada, where they feed, sometimes eating the insect completely and causing its death.