The queen butterfly (Danaus gilippus) is a North and South American butterfly in the family Nymphalidae with a wingspan of 70–88 mm (2.8–3.5 in).[3] It is orange or brown with black wing borders and small white forewing spots on its dorsal wing surface, and reddish ventral wing surface fairly similar to the dorsal surface. The ventral hindwings have black veins and small white spots in a black border. The male has a black androconial scent patch on its dorsal hindwings.[4] It is found throughout the tropics and into the temperate regions of the Americas, Asia and Africa. It can be found in meadows, fields, marshes, deserts, and at the edges of forests
The queen is a member of the genus Danaus, which includes D. plexippus (monarch) and D. eresimus (soldier). It is of the family Nymphalidae of the order Lepidoptera.[13] There are seven subspecies. It is a native of the Nearctic and Neotropical realms.[6] The conservation status of this species is secure, with no reported management needs.[14] Life cycle and morphology Edit Females lay small white eggs one at a time on larval host plants, usually members of the milkweed subfamily Asclepiadoideae. The egg hatches into a black caterpillar with transverse white stripes and yellow spots, and three pairs of long, black filaments. The caterpillar feeds on the host plant and sequesters chemicals that make it distasteful to some predators. It then goes through six instars, after which the larva finds a suitable spot to pupate. The adult emerges 7 to 10 days afterwards. The queen butterfly has multiple generations per year.[4] Egg Edit The queen butterfly oviposits one egg at a time. Each individual egg can be found on leaves, stems, and flower buds of the host.[3] The eggs are usually pale green, but may also be white.[3] It has an ovate conical in shape, a flattened base and slightly truncated top, and is ribbed perpendicularly with raised cross-lines between the ridges.[5][15] Compared to that of the monarch butterfly, the egg of the queen butterfly is taller relative to its width.[7] Caterpillar Edit Comparatively, the mature queen caterpillar is darker and not as brightly colored as the monarch.[4] A queen caterpillar In the larval stage, the queen is a bluish white, with a reddish-brown underside.[3] It has three pairs of black, fleshy tentacles—one is on the head, one is on the second thoracic segment and one is on the eighth abdominal segment[15][16]—but lack spines.[3] When mature, the caterpillar is brown with purplish prolegs. The caterpillar has been observed in the following transverse stripes: blue, green, yellow, white, and blackish brown.[4] The head is black with white rings.[7] There is no hair on the body of the caterpillar.[15] Pupa Edit The pupa is relatively short and thick, tapering rapidly at the end of the abdomen.[5][15] It is pale green, rarely pale pink, and is frequently ornamented with golden spots.[15] A black transverse band edged with gold is on the abdomen.[3] Below this black abdominal band lies another one in blue.[17] The pupa has very few projections; most notably, it is suspended by a long cremaster from a button of silk.[15] As such, the pupa resembles a pendant.[17] In general, the pupa of the queen is smaller and more slender than that of the monarch.[7] Butterfly Edit As an adult, the queen has two cousins to which it bears a striking resemblance: the more common monarch (Danaus plexippus) and the soldier (Danaus eresimus). The queen is a moderately large butterfly. It has an average wingspan of 3.1 inches (7.9 cm) to 3.3 inches (8.4 cm). It is easily distinguishable from its cousin, the monarch, by its darker brown ground color.[5][18] The queen bears a closer resemblance to its other cousin, the soldier (Danaus eresimus).[17] It boasts a very tough and flexible chitinous exoskeleton, unlike most other butterflies.[4] Wing color varies from bright, fulvous brown to rich chocolate, with black marginal bands that are dotted with white or yellow. The underside of the wing is designed much like the upper wing, except it is more pale.[4] The queen has less prominent veins on its wings and lacks the darker, apical shading found in monarchs.[5] The forewing is generally much larger than the rounded hindwing.[15] Both sexes are morphologically similar. The male's and the female's forewing lengths range from 3.7 centimetres (1.5 in) to 4.6 centimetres (1.8 in), with the mean length equaling 4.2 centimetres (1.7 in).[17] The antennae lack scales.[3] Although all danaids have two pairs of walking legs, the forelegs, the first pair located on the prothoracic segment of the abdomen, is stunted and of little use.[4] The forelegs are more atrophied in the male than in the female.[15] The female uses its short forelegs to scratch the surfaces of leaves to determine which ones are suitable hosts for its eggs.[4] On both sexes, only the atrophied forelegs lack claws.[15] However, the male queen has a specialized patch of androconia, or a scent-pouch covered in scales, located on its dorsal hindwing.[4][15][17][19] The position and structure of androconia is used to identify different genera. The male also has one reversibly extensible hair-pencil on each side of its abdomen.[7] Hair-pencils, when in contact with these scales, disseminate pheromones near the female at integral stages of successful courtship.[7]
Distribution and habitat Edit The queen belongs to a family (Danaidae) that is common to both New and Old Worlds, specifically found throughout the tropics and into the temperate regions of the Americas, Asia, and Africa. Stray specimens are found in Europe.[4] The queen is chiefly a tropical species. In the US, it is usually confined to the southern portion of the country. It can be found regularly in peninsular Florida and southern Georgia, as well as in the southern portions of Texas, California, and other states bordering on Mexico.[17] Occasionally, the subspecies of the queen can be found somewhat north, in Kansas, Colorado, and Utah.[4] Periodically, a stray may be found in the Midwest, such as in Missouri.[16] The berenice subspecies is found largely in the Southeast and the strigosus in the Southwest.[3] The queen is also found in Cuba.[5] It is more common in southern Central America, with numbers beginning to rise in Mexico.[4] The queen can be found as far south as Argentina.[7] Although the queen does not undertake dramatic migrations like the monarch, most undertake short-distance travel at tropical latitudes in areas that have a distinct dry season. During those periods, the queen will fly from lowlands to high elevations.[17] Throughout its distribution, the queen can be found on open land, in meadows, fields, and marshes. It displays a more xeric preference in Hispaniola and will fly to the edge of, but seldom penetrate, hammocks and forests.[7] In the southern US, the queen prefers open woodland, fields, and desert.[3] Most likely they are found wherever milkweeds grow.[4] Food sources and host plants Edit Adult feeding on milkweed plant Larval host plants and food sources Edit The queen larvae feed on Apocynaceae (milkweeds and dogbanes).[5] It can survive on a number of hosts. Common plants include butterflyweed (Asclepias tuberosa) and bloodflower (Asclepias curassavica). In the West Indies, blunt-leaved milkweed (Asclepias amplexicaulis) and honey vine (Cynanchum laeve) is favored. The caterpillar has also been observed on Asclepias nivea, Calotropis procea, and Apocynaceae nerium.[7][17] Other reported host genera include the Apocynum, Gonolobus, Sarcostemma, and Stapelia.[17] Adult food sources and host plants Edit As an adult, its feeding habits are less specific. The butterfly feeds predominantly on nectar from flowers and dead foliage, but can also feed on rotting fruit, sweat, and dry or wet dung, among other substances. Even as an adult, the queen is drawn to milkweeds (Apocynaceae).[5] However, the butterfly is also attracted to the Nerium, Funastrum, Vincetoxicum, Philabertia, Stapelia.[4] In addition to the above food sources, males are attracted to Heliotropium, Eupatorium, Senecio, and Crotalaria, plants known to contain the alkaloid lycopsamine. The alkaloid and other precursor compounds from these plants are used to create pheromones used to attract mates.[3] Pheromone precursors are predominantly obtained from Boraginaceae, Asteraceae, and Fabaceae.[19] Defense Edit The queen is one of many insects that derives chemical defenses against its predators from its food plant. Most of the toxic cardenolides that make queens so unpalatable to its predators are sequestered from larval host plants.[20] 