Libellula deplanata bzw. Ladona deplanata ist eine Libellenart der Gattung Libellula aus der Unterfamilie Libellulinae. Ihr Verbreitungsgebiet erstreckt sich über den Osten der USA und reicht von Maine bis Texas.[1]
Das Tier erreicht eine Länge von 31 bis 35 Millimeter, wobei 19 bis 24 Millimeter davon auf das Abdomen entfallen. Die Hinterflügel sind zwischen 22 Millimeter und 26 Millimeter lang.
Das junge Tier ist überwiegend bräunlich, wobei das Braun im Gesicht einen Einschlag ins gelbe hat. Auf dem braunen Thorax befinden sich zwei auffällige braune Streifen. Auch die Beine sind braun. Die Flügel sind durchsichtig bis auf einen Schatten und ein braunes Pterostigma. Durch den Schatten am Flügelansatz läuft ein auffälliger brauner Streifen. Der Scheitel ist schwarz und leicht ausgebuchtet. Das stark abgeflachte Abdomen ist braun mit einem Streifen in der Mitte des Rückens. Mit dem Alterungsprozess werden die Männchen blau.[1]
Die Larven besitzen zentral im Gesicht sitzende Augen und haben ein langes sich zum Ende hin verjüngendes Abdomen. Der Rand des unpaaren Vorderteils des Labium, das sogenannte Prämentum ist eingekerbt. Des Weiteren befindet sich auf Segment acht ein hackenförmiger Vorsatz.[2]
Es besteht zwar eine gewisse Ähnlichkeit zu Erythrodiplax miniscula, diese ist jedoch wesentlich kleiner und hat keinen ausgeprägten Schatten am Flügelansatz. Auch fehlen ihr die Streifen an der Thoraxunterseite. Auch Erythemis simplicicollis fehlen die Streifen, noch dazu ist ihr Gesicht grünlich.[1]
Die Libellula deplanata hat weltweit den Schutzstatus G5, womit sie als in hohen Zahlen vorkommende, sehr weit verbreitete und ungefährdete Art eingestuft wird. Diesen Status erhielt sie am 30. Dezember 1985. In den USA hat sie den national äquivalenten Schutzstatus N5. Auch die östlichen Bundesstaaten der USA haben auf Staatsebene Einstufungen vergeben. Diese sind in der Grafik rechts dargestellt.[3]
Libellula deplanata bzw. Ladona deplanata ist eine Libellenart der Gattung Libellula aus der Unterfamilie Libellulinae. Ihr Verbreitungsgebiet erstreckt sich über den Osten der USA und reicht von Maine bis Texas.
The blue corporal (Ladona deplanata), also known as little corporal,[3] is a dragonfly in the Libellulidae, or skimmer family. First described as Libellula deplanata by Jules Pierre Rambur in 1842, it is common across much of the eastern United States.
When Jules Pierre Rambur first described the blue corporal in 1842, he assigned it to the large skimmer genus Libellula. There it remained until 1897, when James George Needham established the genus Ladona, and transferred the blue corporal (and several other species) to it.[4] Taxonomists have disagreed since as to which genus the dragonfly should be assigned to, with some subsuming members of the genus Ladona into Libellula, and others maintaining the two genera.[4] However, recent molecular DNA studies strongly suggest that Ladona is a monophyletic group which is a sister taxon to Libellula.[5] The blue corporal has, in the past, been considered to be a subspecies of the closely related white corporal.[6]
The etymology of the genus name Ladona is unknown, but the specific name deplanata, meaning "flattened" or "expanded", probably refers to the shape of the blue corporal's abdomen. The word "blue" in its common name refers to the male's coloration, while the word "corporal" refers to two lines on the dragonfly's thorax; in the US military, those with the rank of corporal wear two stripes on their uniforms.[7]
The blue corporal is a small, thickset dragonfly, measuring 29–40 mm (1.1–1.6 in) in length.[8] The male has a dark brown thorax with two wide, bluish, pruinose stripes on the front and a pruinose blue abdomen. His face is black, and his eyes dark brown. The female is brown, with a narrow, pale stripe and an equally narrow black strip on each side of the thorax, and a black dorsal stripe down the center of her abdomen, broadening toward the posterior. Her face and eyes are brown.[9] Both sexes have clear wings with short black streaks at the base, often with a smaller amber streak between them.[8]
The chalk-fronted corporal is larger, and shows a basal spot on the hindwing, rather than the streaks shown by the blue corporal; the adult male chalk-fronted corporal has a white (rather than black) face.[10] The male eastern pondhawk has completely clear wings (with no basal streaks) and green eyes, while the male blue dasher is slimmer, with green eyes and a white face.[11] The male little blue dragonlet is smaller, with clear wings and white cerci.[8]
The blue corporal is common and widespread throughout the eastern United States.[10] Its range extends from Oklahoma to New Hampshire in the north, south to Texas and Florida.[7] It favors the still, infertile waters of sandy-bottomed ponds, lakes and pits, and breeds less frequently in streams than its close relatives do.[10]
Unlike most skimmers—and indeed most dragonflies—the blue corporal typically perches on the ground, though it will sometimes cling vertically to sunlit trees during the late afternoon. Males spend much of their time patrolling the edges of ponds and lakes, resting on banks, low vegetation or floating debris between flights. Unless they are mating or laying eggs, females spend little time near the water. The blue corporal's flight is low and fluttering, occasionally interrupted by hovering.[11]
Like all odonates, the blue corporal is predatory.[12] As larval instars, they prey primarily on midge and mayfly larvae; they are also known to take ostracods and cladocerans, though these make up only a very small percentage of their diet.[13] As adults, they hunt flying insects, taking primarily small flies, beetles and leafhoppers. They are "sally hunters", making quick, short flights after prey from a perch on or near the ground.[12]
The blue corporal has a single brood per year.[14] It mates on the wing. The female, guarded by the male, who hovers above her,[15] deposits her eggs immediately after mating, dipping her abdomen into the water to do so.[11] She spreads her eggs out, spacing them several meters apart around the perimeter of a pond; overall, she lays few eggs in any one site. The young develop synchronously, which increases the amount of intraspecific competition between them.[15] The blue corporal overwinters as a final instar nymph,[11] and the entire population of an area emerges over a one-month period in early spring.[15] The flight period varies with latitude. For example, it flies from November to May in Florida, while in Louisiana it flies from February to May.[16] Further north, it emerges later. In South Carolina, it flies from late March until early May, while in Kansas it flies from April to May.[17] In Ohio and Kentucky, it flies from April to June, and in New Jersey, it flies from April to July.[16]
The International Union for Conservation of Nature has not officially assessed the blue corporal's status, but the dragonfly is said to be common across its range.[11] Like all dragonflies, it faces a variety of threats. As instars, blue corporals are preyed upon by fish; studies have shown that, in response, they tend to use cover more.[14] Larval mortality ranges from 90–97% annually.[13]
The blue corporal (Ladona deplanata), also known as little corporal, is a dragonfly in the Libellulidae, or skimmer family. First described as Libellula deplanata by Jules Pierre Rambur in 1842, it is common across much of the eastern United States.
