The Hesperiids or Skippers and Darts are distinctive small to medium sized butterflies that are often confused with moths. This is because they are often coloured in fairly sombre tones of brown, orange, grey or black, with white, cream or yellowish markings. Despite this, when closely observed they prove to be some of the most interesting butterflies. The males are full of pluck and will vigorously defend a small territory, seeing off much larger insects with a determined and rapid flight.
They are identifiable because of several distinct features. They have relatively small, triangular wings in relation to the their stocky little bodies. Their antennae terminate in clubs that are abruptly hooked, unlike those of most butterflies that are straight. Some of the smaller Dart species have a distinctive way of opening their wings while sunning. They open the forewings just a little, so they are basically held together over their backs, while the hindwings are spread at right angles to the forewings on a horizontal plane.
The caterpillars of Skippers are long and cylindrical with a large head. All of the South Australian Skippers caterpillars feed on sedges and grasses. While doing this they have an unusual method of protecting themselves by making tubular shelters from the grass or sedge leaves. The caterpillar can make silk with it’s mouth parts and uses this silk to either bind the two edges of a single blade of the foodplant together to form a tube, or gathers several grass or sedge blades together, which it also fastens by the edges to create a tubular shelter. This shelter is then silk lined and it usually only is open from one direction. The caterpillar hides in the shelter during the day, emerging at night to feed upon the plant. The caterpillar turns into a chrysalis hidden inside the shelter.
Lycaenids or Blues are a diverse and fascinating group of butterflies. While the common name of “Blues” is apt in the majority of cases, it is quite misleading in others. Some species are a uniform brown or bronze colour, others are purple, coppery-orange or yellow. One Australian species is hot orange-red! They are small butterflies mostly and in fact the smallest butterfly in the world is a Blue. South Australia also has some of local species that are relatively large.
They often have what is known as an “eyespot” near the bottom outer edge of the hindwing, with a tail on the margin of the wing close to it. When the butterflies settle, they tend to do so with their wings closed and they turn their heads towards the ground. This makes the “eyespot” and tail look like a false head. This illusion is further strengthened by the hindwings being rubbed together. This causes the “eye” to move a little and the tails to appear like moving antennae. The effect of this is to cause predatory birds, lizards and insects to target the tail of the butterfly instead of its body, leaving a torn wing, but allowing the insect to fly away. The effectiveness of this measure is shown by the large number of Blue butterflies seen with the tail and the corner of their wings missing.
The caterpillars of many blue butterflies are often quite curiously shaped, they have relatively large, flattened bodies, with the small head hidden away at the front of the body mass. Often these caterpillars are likened to the common Slater or Wood-louse in shape.
Another fascinating aspect of the life history of many Blue butterflies is the way that their caterpillars and even their chrysalises interact with various ants. The ants are attracted to the caterpillar by its ability to secrete a sweet substance from glands at its tail end. In the groups where these interactions occur, sometimes they take the form of various species of ants being casually interested in the caterpillar, milling around it, “milking” it of its honeydew and sometime also showing interest in the chrysalis. In other cases, a single family of ant species closely attends the caterpillar. The ants not only attend the caterpillar and fiercely defend it, but they shepherd it down into the ant nest and lets it form its chrysalis there. Sometime the association goes the full circle, with the caterpillars of some Blue butterflies having adapted from eating plants and living instead as parasites in the ant nests, eating the baby ants!
In South Australia, we have many species of a group of Blue butterflies called Azures. These are of the genus Ogyris and many of them have life histories intimately associated with ants. Most of these species are Mistletoe feeders and in some cases the ants allow the caterpillars to live in their nests at the base of the tree on which the Mistletoe grows, herding the caterpillars up the trunk to feed each evening.
The family NYMPHALIDAE is represented by five subfamilies, of which four of which may be found in the Adelaide region. These contain some of the largest, brightest butterflies to be found in South Australia. Nymphalids are also some of the easiest butterflies to attract to an urban garden setting. Many are highly adaptable in the plants their caterpillars will feed on and can use common garden ornamentals for this purpose. The four families that are likely to occur in Adelaide gardens are:
The Satyrs are butterflies that generally prefer cooler, moister areas that support their grass or sedge caterpillar foodplants, such as woodlands and swamps. They are coloured in browns, oranges, blacks and yellows. Most species have a slow, erratic flight, though most species can fly more rapidly when disturbed. While several species are found in areas east and south of Adelaide, at the present only one species occurs on the plains.
Danaids are large, robust butterflies that contain some of the longest-lived butterflies in the world. The Australian species fall into two groups, one of which are deep blacks or black-browns, often with a purplish sheen and white markings. Only one species of this group has been found in South Australia, where it is extremely rare. The second group has two local representatives. These species are orange or tan with a black border and white markings. One of them is the Wanderer or Monarch, possibly the best-recognised butterfly in the world. Danaids are notable for their highly visible caterpillars, which tend to be ornamented with bright colour schemes and pronounced tendrils. The plants they feed on often contain poisonous substances that render the caterpillars and adult butterflies distasteful to predatory birds and reptiles.
Mostly tropical butterflies, the Swordtails are represented in the Adelaide by one species. This is a relatively late arrival, having first being noted in 1973-`74. The Adult butterflies are large and high-flying. They are called “Swordtails” because of the four sharp tails at the base of the hindwings. The caterpillars are notable for being almost as spectacular as the adult butterfly. Not only are the caterpillars brightly coloured, they have a spectacular head featuring horned projections.
The Nymphs are brightly coloured, fast flying insects. They are also called Brushfoots, as the male butterflies have reduced, brush-like front legs. They include several species that not only look attractive but also are keen feeders from nectar flowers. This, combined with there ability to fly long distances, makes them an ideal group for the butterfly gardener to focus on.
The Papilios or Swallowtails are a group of large, graceful butterflies. In fact the female of one species, the Princes Alexandra Birdwing, has the largest wingspan of any butterfly. While our local South Australian Swallowtails are not nearly this big, they are among some of the larger and more spectacular species that are likely to be seen by the butterfly gardener.
The name “Swallowtail” is derived from the long pair of tails some species have protruding from the base of the hindwings, however this feature is absent in all the South Australian members of the group. When landed and feeding from a flower, the adult butterfly will often rapidly beat their wings, which are held high over their back.
The caterpillars of the Swallowtails often have a thickening or “hump” just behind their heads. This can range from being barely noticeable in some species, to quite pronounced in others.
One of the interesting features of the swallowtail butterflies is the ability of their caterpillars to protrude a forked organ called an “osmeterium” from behind their head. These are extruded quickly and tend to be brightly coloured. They concentrate chemicals from the food plants they eat and these are emitted from this organ. It provides a protective function.
The Pierids or Whites and Yellows are an interesting group of butterflies. Some of the tropical species have separate “Wet-season” and “Dry-season” forms. These two forms can be so dissimilar that it is hard to guess that they are actually colour variations of the same species.
Many Whites and Yellows engage in mass migrations on a sporadic basis, the cause of which is still unexplained and open to several different interpretations.
One species found in Adelaide, the Cabbage (or Small) White, is an agricultural pest that has spread to most corners of the globe in the last hundred years. Having first been found in South Australia in 1941, it has now become so firmly established that it ranks as one of our most common butterflies.
A point of interest is that research into the colouring compounds in the scales of one species of Pierid uncovered a powerful chemotherapy agent!
Their caterpillars tend to be long and cylindrical and are so well camouflaged that they can be very hard to see on the foodplant, even when present in numbers.