Queen (butterfly)

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. There are as many as eleven subspecies recognized. It is a native of the Nearctic and Neotropical realms. The conservation status of this species is secure, with no reported management needs. ==Life cycle and morphology==

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 five 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. The eggs are usually pale green, ovate to conical in shape, with Compared to that of the monarch butterfly, the egg of the queen butterfly is taller relative to its width. Caterpillar The mature queen caterpillar is darker and not as brightly colored as the monarch caterpillar. It is nearly identical to the caterpillar of Danaus chrysippus. In the larval stage, the queen is bluish-white dorsally, with a reddish-brown underside. The pupa has very few projections; most notably, it is suspended by a long cremaster from a button of silk. The queen bears a closer resemblance to the soldier (Danaus eresimus). The positions and structures of androconia are used to identify different genera. The male also has an extensible hair-pencil on each side of its abdomen, which exudes sex pheromones. ==Distribution and habitat==

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. 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, New Mexico, Arizona, and California. Occasionally, the subspecies of the queen can be found somewhat north, in Kansas, Colorado, and Utah. Periodically, a stray may be found in the Midwest, such as in Missouri. The berenice subspecies is found largely in the Southeast and the strigosus in the Southwest. The queen is also found in Cuba. It is more common in southern Central America, with numbers beginning to rise in Mexico. The queen can be found as far south as Argentina. 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. 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. In the southern US, the queen prefers open woodland, fields, and desert. ==Food sources and host plants==

Larval host plants and food sources The queen larvae feed on Apocynaceae (milkweeds and dogbanes). Other reported host genera include Apocynum, Cynanchum (former Sarcostemma species), Gonolobus, and Stapelia. Adult food sources and host plants 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). However, the butterfly is also attracted to the Nerium, Funastrum, Vincetoxicum, Philabertia, Stapelia. 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. Pheromone precursors are predominantly obtained from Boraginaceae, Asteraceae, and Fabaceae. ==Defense==

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. Mimicry in cardenolide-derived defense For quite some time, the queen had been regarded as highly unpalatable to its vertebrate (mainly avian) predators. This is due to the fact that the queen, like its cousin the monarch, feeds largely on Asclepiads. As the queen and the monarch are closely related, it was assumed that the queen also possesses the ability to effectively sequester and store cardenolides present in milkweeds. As such, the queen and the Florida viceroy was long regarded a classic model-mimic example of Batesian mimicry, similar to the relationship exhibited by the monarch and the viceroy. However, the unexpected failure of birds to reject successive queens in an experimental setting Furthermore, evidence from this study led to the hypothesis that the queen actually enjoys an asymmetric mimicry relationship, gaining an advantage from flying in the company of the relatively more unpalatable viceroy. Spatiotemporal variation throughout different areas lead to large differences in unpalatability of queens separated by only a few kilometers. This extensive variation supports the idea that automimicy occurs at the intrapopulation level – palatable queens mimic individuals that have higher cardenolide content. By extension, interspecific mimicry is also highly variable. At hydric inland sites, which contain large numbers of A. curassavica, queens and viceroys are distasteful Müllerian mimics of one another, while at coastal sites queens probably serve as the palatable Batesian mimics of viceroys. Noncardenolide-derived defense Queen unpalatability does not directly mirror either food plant or butterfly cardenolide content. Evidence suggests that the interaction of cardenolides and noncardenolides are utilized for chemical defenses in milkweed butterflies. Wild queens that fed upon S. clausum as larvae but had access to adult-obtained compounds, such as the pyrrolizidine alkaloids (PAs) used for pheromone production, were observed to be significantly less palatable to avian predators than butterflies without chemical defenses. As such, these alkaloids, which are known to deter spider predators, may make a substantial contribution to queen distastefulness. ==Mating==

Males patrol all day to seek females. Females can mate up to 15 times, a significantly higher number than other members of Lepidoptera. When the female comes to rest, the male hovers closely above her and subjects her to further "hair-pencilling" before alighting next to the female and copulating with her. Afterwards, the two engage in a postnuptial flight - the male flies with the female dangling beneath him. Two of the chemicals that comprise this secretion have been identified – a crystalline pyrrolizidinone (ketone) and a viscous terpenoid alcohol (diol). The diol imparts a stickiness that allows the secretion to stay on the dust, and the dust on antennae. The ketone is a releaser pheromone, inducing females to mate. Although insufficient levels of ketone present in the dust particle correlates to lower seductive capacity in the male, In addition, adult female queens whose antennae have been blocked are not receptive to advances from competent male queens. However, physical contact between the male's hair-pencil and the female's antennae does not affect a male's mating success. Males without hair-pencils are no less fertile than males with hair-pencils. That actively hair-pencilling males emit a very definite odor that can even be perceived by humans also supports the idea that it is not the hair-pencil itself that is important in courtship, but rather, the pheromone which the hair-pencil transports. ==Gallery==

Danaus gilippus-egg.jpeg|Egg Queen Caterpillar (36591905866).jpg|Fifth instar caterpillar Queen caterpiller on milkweed cropped.jpg|Caterpillar with black stripes Danaus gilippus-caterpillar red.JPG|Caterpillar with red stripes Danaus gilippus-caterpillar dark.jpg|Dark caterpillar Danaus_gilippus-chrysalis.jpg|Day-old chrysalis Twining milkweed vine.jpg|Adult feeding on Funastrum cynanchoides Danaus_gilippus_at_Asclepias_curassavica03.JPG|Adult feeding on milkweed ==References==