Blog - Butterfly Gear

The Lepidoptera Log - by Steve Woodhall

The Fascinating Life Cycle of Butterflies and Moths:

Mating and Beyond

Butterflies and moths undergo an incredible transformation throughout their life cycle, beginning with the crucial process of mating. Each species has its own unique courtship behaviours and postures, ensuring the continuation of their lineage. Let’s take a closer look at how some South African butterfly and moth species engage in this essential stage of their life cycle.

The Mating Rituals of Butterflies and Moths

Before eggs can be laid and the next generation can begin, male and female butterflies or moths must first mate. This process can vary between species, often involving specific postures or behaviours. ‘Nuptial flights’ are common but here are some examples of the stage where they sit still:

In this photo the male is hanging from the female as they remain coupled. This often happens in butterflies; the females sometimes can be seen flying with the male ‘hanging on’.

Like many butterflies and moths, these are mating in a characteristic tail-to-tail posture. In this image the female is on the left.

These fast-flying moths, known for their hovering flight, are shown here in a tail-to-tail position.

This striking butterfly species follows a mating process in which the male and female fly close together before coupling as shown here.

Some butterflies locate their mates by male territorial behaviour.

Males like this Paradise Skipper are territorial and perch high up on vantage points from which they chase away rivals. Females are seen and pursued. A nuptial flight follows with the pair circling each other high into the sky. The female then lands and the male couples with her.

Male Swallowtails adopt broad territories and patrol them by flying around a circular route, searching for females and nectar sources (flowers). If he spots a female he will pursue her into a shady spot and mate with her.

Males like this Charaxes choose high perches in the forest canopy. Females approach the high point. A nuptial flight follows. The female then lands and the male couples with her. Mating proceeds under cover of the foliage.

A male Acraea will sit or fly high watching for females. When he spots one he will dive onto her, knocking her to the ground. They couple then fly off with the male dangling from the female, then rest on vegetation to complete the process.

Mating is just the first step in the life cycle of these remarkable insects. Once fertilisation occurs, females search for the perfect location to lay their eggs—usually selecting specific host plants that will provide food for their caterpillars once they hatch.

Tiny Beginnings: The Fascinating World of Butterfly and Moth Eggs

The journey of a butterfly or moth begins with an egg—scientifically known as an ovum. These eggs are typically laid on a host plant, the specific plant species that the caterpillars will feed on after hatching. Though often tiny and easily overlooked, butterfly and moth eggs vary greatly in shape, size, and placement. Some are laid individually, while others are deposited in clusters to improve the chances of survival.
Here’s a closer look at the diversity of butterfly and moth eggs and where they can be found:

The female has inserted her eggs into the tiny growing shoots of the Creeping Foxglove (Asystasia gangetica), one of the caterpillar’s host plants. These eggs are barrel-shaped with distinct ribs, a common characteristic of butterflies in the Nymphalinae subfamily, which includes Pansies and Commodores.

These butterflies lay tiny, spherical green eggs, usually on the young leaves of citrus plants. The smooth, round shape is typical of swallowtail butterfly eggs.

Like the Citrus Swallowtail, this species also lays small green eggs, but they are slightly flattened in shape. The female carefully deposits them on the underside of a mature leaf of the host plant, Indian Madder (Rubia cordifolia), ensuring protection from predators and environmental elements.

This Skipper butterfly lays its dome-shaped eggs on blades of grass, the host plant that will provide food for the emerging caterpillars. The domed shape of the egg is characteristic of Skipper species.

Some butterflies in the Acraea group, like the Dark Wanderer, lay their eggs in large batches or ‘rafts’. The baby caterpillars are gregarious and form a phalanx, eating the surface of the leaf in unison and ‘skeletonizing’ it rapidly.

Like most ‘Emperor’ moths this large moth lays its eggs in batches. In captivity, females may lay eggs on cardboard, but in the wild, they attach them to the twigs of their host plant, the Ziziphus mucronata (commonly known as the Wait-a-bit Tree).

Each of these eggs, no matter how small, holds the potential for a remarkable transformation. From these delicate beginnings, tiny caterpillars will soon emerge, ready to embark on the next stage of their metamorphic journey.

The Hungry Caterpillar: A Rapid Growth Phase

Once a butterfly or moth egg hatches, a tiny caterpillar (or larva, in scientific terms) emerges, ready to start feeding. At first, the caterpillar is minuscule—often just a few millimetres long—but its primary goal is to eat and grow as quickly as possible. Over several weeks, it will shed its skin multiple times in a process called ecdysis (or moulting), much like a snake shedding its skin. Each stage between moults is called an instar, and with every moult, the caterpillar grows larger and often changes in appearance.

Caterpillars have developed fascinating strategies to avoid predators, from clever camouflage to secretive behaviours. Here’s a look at the caterpillars of some South African butterflies and moths:

Butterfly Caterpillars

Newly hatched caterpillars of this species, as well as those of closely related species, are tiny, measuring just 2-3mm in length. They start feeding immediately, nibbling on their host plants as they grow.
This caterpillar grows to about 40mm long over 4-5 moults. It takes about a month to six weeks to reach its full size, depending on the season.

A relative of the Dark Blue Pansy, this species has a similar but significantly larger caterpillar. Like its cousin, it feeds on host plants and undergoes multiple moults before pupating.

This tiny Skipper butterfly caterpillar has an unusual trick for staying hidden.

When young, it uses silk to stitch together the sides of a grass blade. As the silk dries and tightens, the leaf closes, forming a secret shelter.

It makes its shelter bigger as it grows.

Once fully grown, the caterpillar will pupate inside its shelter.

This caterpillar has one of the most fascinating camouflage strategies.

When newly hatched, it looks like a bird dropping, helping it avoid being eaten.

Even at the half-grown stage, it still maintains this disguise.

Once fully grown, it adopts a different strategy—it resembles a curled leaf with dead patches, allowing it to blend into its surroundings.

Moth Caterpillars

Like many Hawkmoth species, this caterpillar has a characteristic tail spike, which is already noticeable when it’s very young.

Fully grown Hawkmoth caterpillars come in multiple colour forms, including a brown morph and a green morph. This variation likely helps improve their chances of survival by making them harder for predators to detect.

A truly giant caterpillar!
Young larvae start small but rapidly grow into enormous caterpillars, reaching lengths of over 80mm.
Like other large moth species, these caterpillars consume vast amounts of leaves to fuel their rapid growth before pupating.

Spot the caterpillar!
Many moths in the Geometridae (inchworms) lack the middle ‘prolegs’ you can see on the other caterpillars here.

This allows them to adopt this erect posture, making them look like a leaf petiole.

Caterpillars are one of the most crucial yet vulnerable stages in a butterfly or moth’s life. They have evolved extraordinary adaptations to survive in the wild, from looking like bird droppings to building silk retreats or changing colour to match their environment. After reaching their final size, they prepare for the next stage of their journey: pupation, where they will transform into beautiful butterflies or moths.

The Transformation Begins: The Chrysalis Stage

Once a caterpillar has grown to its full size, it undergoes one of the most dramatic transformations in the natural world. This is the pupal stage, where the caterpillar metamorphoses into a butterfly or moth. During this period, the insect’s body completely reorganises itself, breaking down its larval form and rebuilding it into an adult.

Butterflies and moths have different strategies for this phase. Butterflies typically form an exposed chrysalis (or pupa), relying on camouflage to avoid predators. Some species hang upside down from a surface, attached by a silk pad, while others create a silk harness, known as a girdle, that holds them in place.

Moths, on the other hand, often take a more secretive approach. Many species pupate underground, beneath leaf litter, or tucked under bark. Others spin protective cocoons, which shield them from environmental threats.

Let’s explore some fascinating examples of how butterflies and moths enter this mysterious phase of their life cycle:

Butterfly Pupae (Chrysalides)

This species hangs from its tail, resembling a dried-up leaf. Its camouflage helps it blend into its surroundings, making it harder for predators to spot.

The pupa of this species looks remarkably similar to that of the Dark Blue Pansy, using the same dried-leaf disguise for protection. Because it’s a bigger butterfly the pupa is bigger.

Instead of hanging freely, this butterfly uses a girdle—a fine silk band that holds it in position. The pupa closely resembles a broken twig, making it nearly invisible to predators.

This Skipper butterfly’s caterpillar, like many in its group, constructs a shelter by rolling up a blade of grass and securing it with silk. The pupa remains hidden inside until the adult emerges.

Moth Pupae and Cocoons

Unlike most butterflies, moths like this hawkmoth bury themselves in leaf litter to pupate, hiding away from prying eyes.

Some moths, like this Storm Wave, have very ‘butterfly-like’ pupae that are formed out in the open. They rely on camouflage for protection.

This moth’s pupa is enclosed in a tough cocoon, offering extra protection during this vulnerable stage. In this they are like the popular ‘silkworm’ to which they are related.

When carefully opened (without harming the developing moth), the pupa inside can be seen.

In the wild, the cocoon is typically nestled among the leaves of the host plant, providing natural camouflage.

This stage of the life cycle is a waiting game. Inside the pupa, the caterpillar is dissolving and reforming, preparing to emerge as a fully developed adult.

The Final Transformation: Emerging as an Adult Butterfly or Moth

After spending days—or even weeks—inside the pupa, the butterfly’s transformation is finally complete. But before it can take to the skies, there’s one last crucial step: expanding and hardening its wings.

When the time is right, the adult butterfly breaks free from the pupa, carefully pushing its way out. At this stage, its wings are still crumpled and soft, making it temporarily unable to fly. The butterfly hangs downward, allowing gravity to help stretch out its delicate wings while it pumps fluid from its body into the veins of the wings. This process expands and strengthens the wings, preparing them for flight.

Let’s look at an example of this incredible moment:

These images capture the precise moment when the butterfly emerges, unfolding its new body for the first time.

As the wings begin to take shape, the butterfly remains still, ensuring they fully extend.

With its wings now expanded and hardened, the butterfly is ready for its first flight.

What do the other adults look like?

This is a female of this relative of the Acraeas, laying a batch of eggs on her host plant, the toxic Mamba Greenstem Adenia gummifera. Her pied, black-and-white pattern is a warning to predators that she’s carrying poisons absorbed from the plant when she was a caterpillar!

Geometridae adults – that come from ‘inchworms’ – look just like butterflies to many people! This one looks brightly coloured but when resting on the bark of a tree it would be well camouflaged.

This ‘Emperor’ moth is huge – with a wingspan of more than 120mm. It’s related to the Giant Atlas moths of south-east Asia, that can be almost twice as big. It can be found along the eastern side of Africa.

This final step is a delicate and vulnerable time. If the wings don’t expand correctly or harden properly, the butterfly may never be able to fly. But once everything is set, the butterfly takes off into the world, searching for nectar, mates, and a new generation to begin the cycle once again.

The Incredible Journey of Butterflies and Moths

From a tiny egg to a magnificent adult, the life cycle of butterflies and moths is a story of resilience, transformation, and survival. Each stage—mating, egg-laying, hatching, caterpillar growth, pupation, and emergence—plays a crucial role in ensuring the next generation continues. Along the way, these insects have evolved remarkable adaptations to protect themselves, from camouflage and mimicry to unique feeding strategies and survival tactics. They vary enormously in shape, colour, and form, at all their life stages. We’ve only scratched the surface here.

But their journey doesn’t end at flight. As adults, butterflies and moths contribute to ecosystems as pollinators, food sources for other species, and indicators of environmental health. By understanding and appreciating their life cycle, we can take steps to support them—whether by planting host plants, reducing pesticide use, or simply observing and learning from these fascinating creatures.

Next time you spot a butterfly fluttering past, take a moment to wonder: What incredible journey has it taken to reach this moment?

Category: Blog

The Mating Rituals of Butterflies and Moths

Citrus Swallowtails

Long Horned Swifts

African Hummingbird Hawkmoths

Dark Blue Pansy

African Paradise Skipper

Mocker Swallowtail

Blue-spotted Charaxes

Garden Acraeas

Tiny Beginnings: The Fascinating World of Butterfly and Moth Eggs

Dark Blue Pansy eggs

Citrus Swallowtail egg on young Citrus leaf

African Hummingbird Hawkmoth eggs

Long Horned Swift egg

Dark Wanderer eggs

White-ringed Atlas Moth eggs

The Hungry Caterpillar: A Rapid Growth Phase

Butterfly Caterpillars

Dark Blue Pansy very young caterpillar

Dark Blue Pansy fully grown caterpillar

Common Diadem Fully Grown Caterpillar

Long Horned Swift very young caterpillar

Long Horned Swift fully grown caterpillar

Citrus Swallowtail very young caterpillar

Citrus Swallowtail half grown caterpillar

Citrus Swallowtail fully grown caterpillar

Moth Caterpillars

African Hummingbird Hawkmoth very young caterpillar

African Hummingbird Hawkmoth grown caterpillar green morph

White-ringed Atlas Moth fully grown larva

Storm Wave moth fully grown larva

The Transformation Begins: The Chrysalis Stage

Butterfly Pupae (Chrysalides)

Dark Blue Pansy pupa

Common Diadem pupa

Citrus Swallowtail pupa

Long Horned Swift pupa

Moth Pupae and Cocoons

African Hummingbird Hawkmoth pupa

Storm Wave moth pupa

White-ringed Atlas Moth pupa

The Final Transformation: Emerging as an Adult Butterfly or Moth

Common Diadem emerging

Common Diadem emerged

Common Diadem

What do the other adults look like?

Dark Wanderer adult

Storm Wave adult

White-ringed Atlas Moth

The Incredible Journey of Butterflies and Moths