Butterflies

Butterflies are fascinating insects. There are over 20,000 species worldwide. The species vary from each other in a number of ways, including size, wing colouring, flight patterns, mating rituals, overwintering habits, and preferred food sources. Some species are widely distributed while others are quite localized. And while a few different species migrate, some fly only short distances while monarch butterflies undertake an astounding annual migration across North America.  

Butterfly Life Cycle 

The butterfly life cycle begins when a female butterfly lays a fertilized egg (or eggs) on a plant. The larvae (caterpillars) that hatch from those eggs usually have very specific food needs. Larvae tend to stick close to the plant they hatched on. For this reason, adult female butterflies carefully choose which plants to lay their eggs on. 

Each species varies a little, but butterfly larvae typically do very little except eat their host plant and grow. As they grow, they shed (molt) their exoskeletons, which become too small and constricting. After a successive number of molts, they are ready to move onto the next stage of their lives: metamorphosis. 

When butterflies metamorphose (or pupate), they go through an intense chemical process that breaks down their existing body and changes it to a winged adult butterfly. To pupate, a larva creates a chrysalis, which it usually attaches to the underside of plant leaves or stems.  As explained at the Gardens with Wings website, its body is basically liquefied and then restructured into the form of an adult butterfly. 

Soon after emerging from its chrysalis, a butterfly will begin to take part in mating rituals so that its life cycle continues. 

Butterfly Mating Rituals 

Although scientists have only studied the mating rituals of a few different butterfly species, some general patterns are noticeable. 

Most female butterflies are ready to mate shortly after emerging from their chrysalides. Most male butterflies, however, become sexually mature 4-5 days after they emerge. And it’s most often the males that initiate mating. 

Joseph Castro explain at livescience.com, that male butterflies are either perchers or patrollers. Perchers bide their time and wait for a suitable female to fly by. Patrollers flutter around, searching for a mate. It’s a butterfly’s wing colours and patterns that help them locate mates of the same species.  

Once a male spots a potential mate, he will fly close by her or even perform a courtship dance. The flight has a purpose: it helps to spread the pheromones the male releases in a bid to attract the female.  

In most cases, it’s up to the female to decide how to proceed. She may engage in the courtship dance as well, she may just go ahead and mate with the male, or she may decide that the male is not a good match for her and simply fly away. 

But some species have different rituals, where the female butterfly doesn’t have as much choice. Male monarchs for instance, engage in “aerial takedown,” where they simply grab suitable mates and carry them to the ground where mating takes place. 

Whatever rituals they engage in to initiate mating, the male uses his clasper to hold tightly to the female while their abdomens are touching. And as they hold tightly together, the male passes sperm to the female’s reproductive tract. 

Butterfly Food Sources 

Most species of adult butterflies subsist on flower nectar. Often butterflies will feed on any nectar that’s available. However, some plants produce rich nectar that is highly attractive to the insects. And, some species of butterflies prefer certain flowers over others. Monarch butterflies, for example, feed almost exclusively on milkweed. Interestingly, milkweed can be toxic to other living beings. However, monarchs have adapted to that toxicity. Their bodies absorb the toxins, making them poisonous and thus unappealing to natural butterfly predators.  

A few species prefer different food sources, though. Some choose to feed on overripe or rotting fruit. 

Overwintering Habits 

According to the North American Butterfly Association, most butterflies that spend the winter in freezing climates are able to resist the cold in one stage of their lifecycle. Many species overwinter as caterpillars or as pupas (caterpillars in their chrysalises). A few species overwinter as adults, hibernating in crevices. A few overwinter as eggs. And one notable exception, the Monarch, undertakes a massive migration south each fall.  

Monarch Migration 

Monarch butterflies are unique in that they undertake a massive annual migration. Monarchs that emerge from their chrysalises in late summer and fall are physically different from that year’s earlier generations of butterflies. As the Espace pour la vie website explains, this generation of butterflies doesn’t have fully formed reproductive organs. Instead of using their energy to reproduce, these butterflies fly from eastern Canada and the United States to the the Sierra Madre Mountains in Mexico. (Monarchs from west of the Rocky Mountains have a shorter journey, as they flock instead to California.) 

Scientists aren’t sure why monarch butterflies, among all the species, migrate. It is true that they can’t withstand harsh winter temperatures but other species hibernate in their local areas through the winter months. According to National Geographic, scientists speculate that the insects may be choosing to leave environments where parasites have accumulated over the summer. And, as for the return migration the next spring, its most likely that for the journey north, butterflies follow the emerging blooms of the milkweed plant.  

Butterflies are unique in the insect world, for their size and beauty. But with more than 20,000 different species, several types of butterflies have unique features that set them apart from other butterflies as well. It can be extremely educational and rewarding to watch the different species live out their life cycles as they frequent your butterfly garden.