Butterfly Mating

Butterfly mating happens with every butterfly species.
When selecting a partner the goal for the female is to find
the best male to continue a strong genetic line.

Photo: Lawrence Wee

From the moment the female butterfly emerges from her pupa, the imago is ready to mate. Most male butterflies are ready after one hour.

With some species, the male will wait for female to emerge from her butterfly pupa, sometimes even helping her. The male will mate with her before her wings have even filled with hemolymph which enables the female to fly. Other male butterfly species will patrol or perch while using their odor and wing colors to attract females.

Patrolling is when the male flies through their habitat seeking a receptive and suitable female to mate with. He flies in a linear pattern - flying straight in open fields or through trails. The male is able to identify the female through her pheromones and wing colors, including any ability to see ultraviolet patterns on wings with their compound eyes.

Pheromones are scent secretions by butterflies emitted to cause a specific reaction. These can be patches found on their wings.

Antennae also house sensilla, or sensory hairs, that respond to butterfly mating signals.

Perching is when a male not from a specific butterfly habitat sits on top of a leaf or twig, usually upon a hill, waiting for a receptive and suitable female to pass by. If other insects pass by, the male will fly to investigate, ultimately returning to the perch. This method usually works best for the male that is rare to the environment. In this case males usually move from different sites, or environments, throughout their life.

If another male passes by, the already perched male and the intruding male will become engaged in an upward spiraling flight. It is not uncommon for other males to join in. Originally it was thought this was their method of fighting but it is not.

While males can appear to be territorial this is usually not the case, only a rare few are aggressive. While engaged in upward flight, the males are actually looking around to see if a female passes by allowing one male to gain an edge to pursue her.

Many patrolling, perched and other males roost, or rest, instinctively to certain area seeking butterfly mating opportunities at specific times for their species. The same is true for females. Instinctively they roost to these same areas seeking mates. This is a strategy and those butterflies that have perfected it mate regularly. These highly instinctive male and female butterflies are key in extreme climates because their instincts help prevent extinction.

Butterflies also adhere to a daily schedule which consists of feeding and pursuing mates. Trap Lining is the daily route a butterfly adheres to for finding food. The same for patrolling or perching, these are done at certain times of morning, midday or all day depending on the species. Females also instinctively adhere to these schedules and after butterfly mating she deposits her eggs routinely.

Photo: Janice Mccafferty

When the male finds a potential mate he flies closer to her releasing pheromones. His flutter may also be different in this mating dance then his usual flight patterns. It is believed that pheromones are more important in the role of mate recognition than the initial visual cues. If the female is receptive she and the male check scents and colors to verify they are of the same species. During this time the female may accept or reject the males mating offer.

Butterfly behaviors prior to copulation can differ slightly between species. For example, most butterfly species court by having their mating dance which spirals in an upward motion, many times to mate in high places. Other species will do the same while seeking lower areas to mate. Finally, other species fly close to their preferred host plant so the female can deposit her eggs soon after mating occurs.

As with patrolling or perching, butterfly mating usually occurs about the same time of day for all butterfly species. This is the same for ovipositon. For example, Sulphlurs usually lay eggs about midday.

Once the two butterflies determine there is a match, any courting it is quick. The female then instinctively falls to the ground or is forced to the ground by the male and butterfly mating will begin.

Butterfly mating for most butterflies averages anywhere from minutes up to three hours, rarely beyond this but it does happen. During mating the male and female attach abdomens and each are facing opposite directions. Many males grasp the females abdomen with claspers, also called valvae.

Interestingly, it has been discovered that the male butterfly has a light receptor at the end of the sexual organs in his abdomen. When this receptor starts to go from light to dark, it is then the sperm packet is transferred to the female. Female's also have a light receptor but they are not used for mating. Still uncertain as to their purpose, it is believed that the receptors may play a role in her depositing butterfly eggs.

While abdomens are attached some butterfly species can fly, carrying their mates if they are startled or feel threatened. This is not the case with all butterfly species. Of those that can fly some are the males, others are the females.

Some females can mate multiple times are capable of mating immediately after copulation. Males, on the other hand, have to wait about eight hours to produce spermatophore. Spermatophore is the sperm and nutrition package transferred to the female in order for her to produce and deposit her eggs.

Some males will place a copulatory in the female's abdomen
to prevent her from mating again.

A copulatory, also known as a sphragis, is a waxy secretion produced during butterfly mating which contains sperm and other nutrients. Clouded and Small Apollos are known to do this.

A copulatory increases the chance that one male successfully produces offspring by preventing the female from being inseminated by another male.

Photo: Vasiliy Vishnevskiy

Some females refuse a copulatory so she can be more desirable for butterfly mating again. Other female species, such as C. Cressida Swallowtail, developed genitalia that makes it difficult for the sphragis to stay in place. Other females can digest the sphragis and mate again.

The female isn't always receptive to mating with the male and may reject him. Whether they are emerging from their pupa or a flying imago, different species of female butterflies reject males differently.

If a female rejects the male during the courting dance she will start flying in a straight line up and down. The male will become discouraged and eventually fly away.
Some females will mimic a male to discourage him pursuing her.

Some females crawl or fly away.

Some females place their legs around their own abdomen in a manner to close herself so the male can not enter.

Some females have stick clubs, or glands, that produce a smell to repel the male.

Females can also indicate rejection with a different flutter than the flutter they normally use in flight.

Rejection is instinctive in a female, nothing conscious. Reasons why a female will reject a male for mating are:

Female may not need to mate again.
Testing the male. Seeking out the aggressive males to mate with for a preferred gene pool.

Some females never mate in their life time. If she doesn't mate right away it's unlikely she ever will. This is common. Other females will only mate once and others mate multiple times.

FYI

The female produces pheromones which are found in wing scales.
The male can smell female pheromones up to one mile away to find female.
After mating the male flies off, some die soon after.
Mating may never occur for some butterflies up to several times in their lifetime. Smaller butterflies have a short mating span larger butterflies have a longer mating span.
Should you come upon mating butterflies the female can be identified because she usually has a larger abdomen.