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A spring carnival of a different kind is about to brighten your backyard.
The butterflies of south-eastern Australia are getting ready to burst forth in their annual race to reproduce.
But there are worrying signs the carnival may soon be over for several species, according to Nature Glenelg Trust senior ecologist Bryan Haywood, who co-authored the report Butterflies on the Brink.
“Butterflies on the Brink came out of a national workshop last year on 26 species we were concerned may go extinct within 20 years,” Mr Haywood said.
“In western Victoria and eastern South Australia, which is where I work, they include the bright-eyed brown, banks’ brown, and the eastern bronze azure.
“Climate change potentially has an influence but it’s primarily disturbance of habitat and loss of habitat. It can be a decline in remnant bush and wetland, changing their environment by clearing it or draining it for other uses, or the increasing frequency of fires.
“The report estimated that five butterflies could be lost to extinction by 2040 unless management improves.”
There is cause for optimism.
Nature Glenelg Trust has successfully translocated the silver xenica butterfly from Victoria, where it is still abundant, into South Australia, where it has declined.
“We thought [the silver xenica] may be in danger of extinction in South Australia, so we prepared a plan of how and when to gather females from a population that was secure and in large numbers, and release them where we thought suitable,” Mr Haywood said.
“It may be a model we could use for other endangered butterflies.”
The other spring carnival
Butterflies can hatch at any time of the year in the tropics but in south-eastern Australia most emerge from their chrysalis in spring.
Life as a butterfly is often spectacularly short. The male common brown, for example, lives just a few months.
“For us in the wetter and colder parts of Australia, we have several months of the year where we don’t have butterflies,” Mr Haywood said.
“We wouldn’t get new emergences between May and August. They will be in a caterpillar form and then pupating into a chrysalis from [effectively a cocoon].
“Within hours of emerging as an adult butterfly, males and females are interacting with each other.
“Males develop small areas that we call territories, that they will defend. They will shoo other males away.
“Males and females generally emerge at the same time but in the case of the common brown, the male tends to emerge a few weeks earlier. After they mate, the males tend to die off in December and January.
“But even the females, over the hottest part of summer, tend not to be very active. They tend to hang out in the leaf litter so numbers can tend to appear low even when they are not.
“After the males have died off and we get into autumn, that’s when you can see clouds of females, and people have spoken of fond memories of walking along a forest track and having clouds of butterflies come up off the ground.
“They are just wandering around looking for suitable plants to lay their eggs, which eventually hatch into caterpillars over autumn into winter, and the cycle begins again.”
Among the native species, there are two common introduced species. The white cabbage butterfly is a horticultural pest, the caterpillars attacking cabbages, cauliflower, Brussels sprouts, broccoli and other vegetable crops.
The monarch butterfly caterpillars, meanwhile, feed on milkweed, making them in the eyes of farmers at least more friend than foe.
A spotter’s guide
Butterflies, quite conveniently, are divided into colour groups for the most part.
The groupings are whites, blues (and coppers), browns and another two groups: swallowtails and skippers.
The spectacular swallowtails (generally the largest and most colourful butterflies) are generally tropical, but south-eastern Australia has a large variety of blues and browns, along with skippers, which are something of a halfway house between butterflies and moths.
Mr Haywood said butterfly watchers are asked not to catch and remove specimens from the wild but collecting photos of them is encouraged.
Hesperiidae – skippers (usually fly with a skipping motion)
- White-banded grass dart (Taractrocera papyria) — tiny butterfly, characteristic white stripe on the underside of the hind wing.
- Varied sedge skipper (Hesperilla donnysa) – medium size butterfly, fast flyer, underwing spots differentiate from other Hesperilla species.
- Southern grass dart (Ocybadistes walker) – tiny to small butterfly, fast flyer, has a more orange appearance compared with white-banded grass dart.
- Splendid ochre (Trapezites symmomus) — very large skipper, with large silver spots on the underside of hind wing.
- Orange ochre (Trapezites eleina) – medium-size skipper, with prominent spots on the underside of the hind wing.
Nymphalidae – browns (generally fly with a fluttering motion)
- Australian painted lady (Vanessa kershawi) – medium size, males and females are the same. Fast flying and one of the three species that glide with wings out flat.
- Australian admiral (Vanessa itea) — medium size, males and females look the same. Fast flying and one of the three species that glide with wings out flat. Characteristic yellow spot on the forewing.
- Common brown (Heteronympha merope) – medium to large, males and females are different. Male smaller than female. Female has yellow and black on the forewing. Typical fluttering flight.
- Marbled xenica (Geitoneura klugii) – small to medium, males and females are different. Male smaller than female. Female has yellow and black on forewing. Typical fluttering flight.
- Monarch (Danaus plexippus) – large butterfly. Males and females similar, but males have sex marks on hind wing. Slow fluttering/meandering flight. Also known as wanderer butterfly.
- Silver Xenica (Oreixenica lathoniella) – small. Males and females are similar, generally a slow to medium-paced fluttering flight. Similar to striped xenica, but silver markings on the underside of hind wing are scalloped shaped instead of straight
- Bright-eyed brown (Heteronympha cordace wilsoni) – small to medium. Males and females appear similar, generally a slow to medium-paced fluttering flight. Similar to male common brown but with prominent eye spots on both wings.
Lycanidae – blues
- Long-tailed pea blue (Lampides boeticus) – small to medium size. Can be fast flying, at head height and has short tail-like scales on hind wing with a blue eye spot.
- Saltbush blue (Theclinesthes serpentata) – very small in size. Rapid flight close to the ground but not always travelling far. Very mottled underside of hind wing.
- Grassland copper (Lucia limbaria) – very small in size. Prominent copper patch on forewing in males with mottled underside of hind wing. Overall brown in colour.
- Common grass blue (Zizina labradus) – very small in size. Fast fluttering flight close to the ground in open areas. Can be bright blue on top side of wings and grey underneath with no prominent markings unlike other blues.
Pieridae – whites
- Cabbage white (Pieris rapae) – medium in size, and an introduced horticultural pest. Meandering flight over open areas, all white with black markings at apex of forewing plus black spots on forewing and top of hind wing.
Papilionidae – swallowtails
- Dainty swallowtail (Papilio anactus) — large. Sometimes fast flying but generally meandering with some gliding/sailing-like behaviours. Common in citrus growing areas and gardens, and has established colonies outside of the natural range of its host plants.
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