The Small Postman (Longwing), also confusingly called the Red
Postman, is one of the Heliconian family native from Mexico to northern South America. It has a greater range to both the north and the south than the similar Common Postman. It has many forms and subspecies over its range; most of the forms are mimicked by the Common Postman as well as other Heliconians.
The "standard" form, mimicked by the Common Postman, is a black
background with one red vertical bar on each forewing and a
horizontal white bar on the hindwing, shown at the top.
Immediately above and below is a variation with no white bar
on the hind wing, broader, pinker bar on the forewing, blue
iridescence on the background and "piano key" edging.
Although there is no white hind wing bar on the topside in this variation, there is the usual white bar on the underside.
Since the Small Postman is not much smaller than the Common, both having a wingspan around 70-75mm (wingspan of the Small Postman can vary from 55 to 80mm), there are two other ways to differentiate their "standard" form from the underside (not infallible): the Common has three red spots near the body on the hind wing compared to four spots for the Small, although the spots sometimes merge, as shown above centre and right, or can be indistinct; and the white bar on the wing usually, but not always, goes nearly to the outside edge on the Small.
Above centre and right, a further variation with an elongated pink bar on the forewing and an extra red bar on the underside hind wing. This may be another mimic or subspecies?
Like other Heliconians, adults not only drink nectar but also eat pollen (shown on tongue above right) which improves their lifespan from several days to 2-3 months.
Caterpillars eat Passion Flower vines which makes them and the adult butterflies unpalatable to predators.