Synonyms and other taxonomic changes
Mistaken for Tibicen canicularis by several authors. First described as a new species in 1907 by John B. Smith and John A. Grossbeck as Cicada davisi
Explanation of Names
Named after Wiliam Thompson Davis
, co-author of an article on cicadas a year before, that prompted Smith and Grossbeck's study and the article based on it.
Color and pattern are certainly not absolutes for species id., however, can be helpful. Regarding measurements, these too can be misleading; some individuals may not adhere to "specified measurements" used to "key out" a species. Within this particular taxon, head & mesonotal/thoracic widths are subject to some latitude of variation (may be an artifact of individual variation, geographic origin and/or gender - ??).
As seen in the Dog-Day Cicada, Tibicen canicularis, this particular taxon can be HIGHLY VARIABLE in color, pattern and size. There may be some geographic tendencies regarding observed variations between and among individuals (? - larger series/collections can better address these observations). Specimens collected from coastal populations and those from central & south Florida are usually green and often quite large (~1.5x the size of specimens collected from more northern and inland localities and may equate or even slightly exceed 2 inches in total length). These larger green coastal types are often mistaken for other Tibicen species (like pruinosus).
Davis' Southeastern Dog-Day Cicadas often exhibit a range of color morphs (incl. but not limited to Dark Green, Light Green, Leaf Green, Olive, Taupe, Reddish-Brown, Dark Brown and/or any combination). All known color forms and intermediates may be encountered across the species' range; however, there may be some geographic (or habitat) tendencies to the frequency with which these forms are encountered (?).
DESCRIPTION: Head noticeably wider than widest point of pronotum (eyes usually protrude beyond the widest point of the prothorax). Males possess oblong, tan opercula which are usually half, to slightly less than half, abdominal length. Color variable, pronotal collar usually green to dark green but may be dark brown or reddish-brown in some individuals. Eye color is highly variable and may be black, dark brown, gray, tan, greenish and/or slate blue. The tips of forewings and veins are often smoky colored (heavily infuscated). Underside of abdomen usually lacks a well developed black stripe; however, some specimens may have slight dark edging to ventral segments (sternites).
In general, Davis' Southeastern Dog-Day Cicada is less than 2 inches in total length (incl. wings). The head to thorax ratios/body proportions are often similar to those seen in auriferus and superbus. Davis' dog-day cicada and related taxa are usu. more compact with wider heads relative to "pronotal width" and seem to lack a "neck" (i.e. the sides of the pronotum are usually nr. ~parallel / the angle of the image should be taken into account). In canicularis and related taxa, the pronotum is often slightly constricted behind the head (i.e. the sides of the pronotum are more evidently convergent anteriorly & divergent posteriorly giving the insect a more pronounced neck and somewhat "bug-eyed" appearance).
See comments under photos in guide. Song described as "a short brassy buzz-saw like sound lasting about 10 seconds" (Cicadas.info
), and is said to be given in the morning to early afternoon, never in evening.
song: a loud, high-pitched whine with a slight vibration (~like a power saw cutting wood) - drawn out and usu. lasting several seconds before fading at the end
Similar to and often confused with canicularis and auriferus
The range of “Davis’s Southeastern Dog-day Cicada” (Tibicen davisi) includes much of the southeastern United States.
The nominate form or "typical T. davisi" is most common east of the Mississippi River (incl. FL, GA, AL, MS, c. & e. SC, c. & e. NC, & e. VA) and known from isolates in the coastal plain of a few Trans-Mississippi states (incl. LA, AR, & TX). Reports for "davisi" and its northern most limits in the east suggest Maryland, Delaware, & se. New Jersey(?). Some reports even suggest extreme sc. TN and nw. Alabama? - however, these reports and specimens may be representative of ssp. "harnedi".
Nominate "davisi" is a pine specialist and associated with "long needle" pine species and pine forests of the Atlantic & Gulf Coastal Plain. Populations of "davisi" are known to extend into the lower "Hill Country" following the Fall-line Hills of the Piedmont Plateau. It is the distribution of the host trees that seems to define the range of nominate davisi occurring east of the Miss. R.
The taxon or ssp. known as "harnedi" appears to occupy mixed forests and open lands along the Mississippi River and upper Gulf Coastal Plain. Populations of this cicada can extend into the lower "Hill Country" following the Fall-line Hills of the Cumberland Plateau (perhaps as far east as nw. Alabama). Reports for the northern most limits in the west (i.e. "harnedi") suggest w. TN and e. Arkansas and possibly extreme se. MO? where it likely blends with and is certainly replaced by T. auriferus.
NOTE: This species is absent from higher elevations and does not seem to occur in the Appalachians (perhaps isolates of the nominate form occur in peripheral lower elevations)
NOTE: Nominate "ssp. davisi" is replaced by "ssp. harnedi" along the eastern and western parts of the Mississippi River (e. AR, wc. MS & sw. TN) and by auriferus further to the west and north (n. Louisiana, Arkansas, Missouri, s. Iowa west into the Central Plains States - ne. & e. TX, OK, KS and NE). Northern and western reports of "T. davisi" in the adjacent plains states have thus far proven to be Tibicen auriferus (Say 1825), "Plains Dog-day Cicada" and those in w. TN and e. AR are "T. davisi ssp. harnedi" (NOTE: the latter of which appears to be more closely allied with auriferus and may belong to that species).
This species is most certainly associated with pines, particularly the southern "long-leaf" pine varieties (Loblolly, Slash, etc.)
Late summer to fall.
July/August-October (North Carolina)
July/August-November (coastal/s. Georgia, s. Alabama, s. Mississippi & n. Florida)
(pers. comm./observ. some years may be active into early January in central/south Florida!)
All stages seem to prefer Pines
In captivity, adults will feed from other plants, but prefer and do best on Pines.
This species is a relatively long lived species in captivity - relative to other members of the Genus - and adults have been kept for more than 2 weeks.
eggs usually laid in dead twigs, wood or bark
(occasionally eggs may be laid in living stems and twigs)
eggs hatch and nymphs burrow into the soil
nymphs feed on the sap in roots for several years (prefer Pines)
Final instar nymphs emerge and develop into winged adults (emergence for this species usu. occurs at night - between 9:00PM & Mid-night)
Very common across the southeast
Most often confused with the following:
"Southern Dog-day Cicadas"
Loosely & informally referred to as the "Southern Dog-day Cicadas" ("coined", Bill Reynolds
), the following taxa are mostly "southern" in distribution and appear to be closely related. These cicadas share several traits, incl. elongated opercula in the males, rapid trill and/or clicking calls, and unusually wide heads relative to body dimension (head widths usu. exceed thoracic widths).
(*appears to be the most divergent member within this group - ??)
"Green Tibicen Species"
Collectively, yet informally, referred to as the "Green Tibicen species" (per. comm.), the following cicadas are often difficult to differentiate and all appear to be very closely related. Genitalic analysis of the males suggest these species are very closely related and morphological differences between and among the species are slight. It is also thought (based on observations) that several of these may be involved in complex hybrid zones; however, more work is needed to substantiate and better understand these observations.
Tibicen pruinosus pruinosus var. fulvus Beamer 1924 [syn. T. pruinosa var. fulva], "Pale Scissor(s) Grinder Cicada"