Long-Wing Butterflies Heliconiidae
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Long-wing Butterflies Heliconiidae This is a neotropical family, sometimes Gulf Fritillary treated as a subfamily of Nymphalidae. Heliconiids are brightly coloured butter Agraulis vanillae (Unnaeus, 1758) flies with a distinctive wing-shape, the Plate lil (1,2) forewing being long and narrow with its apex extended much further beyond the outer margin of the hindwing than in other families of butterflies. The larvae of Heliconiidae feed on Pas sion Flower vines (Passifloraceae). Alka loids from these plants are sequestered by the larvae so that they, and ensuing stages, are unpalatable to predators. But terflies which adopt distastefulness as a protection, rather than concealment (crypsis), must advertise that they are to be avoided. They must evolve an appearance, a warning (aposematic) pattern, which predators will remember. An inexperi enced or naive predator will then rapidly learn, after just a few encounters, to asso Male Gulf Fritillary, GC (18.i.2008), RRA ciate an unpleasant experience with this warning pattern. The memorability of a Recognition warning pattern is enhanced if it is sim FWL 30-38 mm. (specimens from Grand ple, and in contrasting bold colours which Cayman have FWL usually in excess of are repeated on upper and under wing 34 mm., those from the Sister Islands are surfaces. Aposematic butterflies often fly on average smaller). The upper surface slowly or glide, and they may aggregate, of the Gulf Fritillary is orange, brighter in so as to enhance the visual impact of their the male, with black markings. At a dis warning colouration. Heliconiids are resi tance it could be mistaken for Euptoieta lient butterflies with a capacity to tolerate hegesia (above) or Dryas iulia (below}, some physical damage incurred when but the silver markings on the under sur 'sampled' by a would-be predator. They face of the hindwings readily distinguish are also exceptionally long-lived butter Agraulis vanillae (which is often placed flies. The three Caymanian representa in the genus Dione HUbner, 1819) from tives of Heliconiidae together display all both of these species. The underside of of these characteristics. the forewing also has some apical silver spots, and there is a pink basal flush in the freshly emerged insect. 60 Gulf Fritillary GC (9.ii.2006), MLA Female Gulf Fritillary captured by a white crab spider on Rabbit Thistle (fridax procumbens), CB (26.i.2008), RRA Subspecies insularis ranges from the Bahamas south Agraulis vanillae insularis Maynard, to about Dominica (above), and the nomi 1889 flies in the Bahamas and more nate subspecies (A v. vanillae) extends northerly West Indies, from Cuba to Domi the range of the species from St Lucia, nica and including the Cayman Islands. It and perhaps Martinique, into South is characterised by a well-developed black America as far as Argentina. spot mid-way between base and outer margin in the space between the two Cayman Islands distribution hindmost veins of the forewing. This spot Grand Cayman, Little Cayman, Cayman is reduced or absent in most individuals Brae belonging to the other subspecies, but butterflies at the indefinite southern ex Habitat tent of the range of A. v. insularis, in the The Gulf Fritillary is a common Cayman Lesser Antilles, intergrade with the nomi ian butterfly which may be seen almost nate subspecies. anywhere in the islands except in man groves and thick woodland. It is plen Species' range tiful on beach ridges and in pastures, Agraulis vanillae occurs in the Gulf of but perhaps has a preference for scrub, Mexico area and Florida (as A. v. nigrior wood edges, hedgerows and uncultivated Michener), migrating north in the United ground verging paths and roads. It is a States but not breeding beyond the nor familiar garden insect. thern limit of Passiflora survival. A. v. 61 .