The butterfly lifecycle
1 - Egg
- anatomy, oviposition
2 - Caterpillar
- hatching, feeding and development
- cannibals, carnivores and myrmecophiles
- survival mechanisms,
armature, camouflage / disguise
co-evolution with plants
- pupation, metamorphosis
- emergence, feeding
- mate location and courtship
10 - Adult
- daily routine, roosting, hibernation, lifespan
Butterflies tend to have short lives. Females of most species often
have less than a week to find a mate, copulate, search for
oviposition sites, and lay their eggs. Rapid mate location and
recognition are therefore vital - butterflies can't afford to waste
time on fruitless encounters with species other than their own.
Orange tip Anthocharis cardamines,
male, Dunsfold, Surrey, England ©
Butterflies can see all the colours of the
visible spectrum, plus ultra violet. Brightly coloured species such
as the Orange tip
are able to detect others of their own kind
from several meters away. Experiments with bright blue
species show that waving blue foil in the air is very effective at
attracting them towards observers.
Several researchers have attempted to unravel the mysteries of
visual communication / recognition in butterflies. Magnus found that
males of Argynnis paphia used "paper
butterflies" attached to a rotor arm to test the reaction of male
Argynnis paphia to numerous variations
of colours, shapes, sizes and patterns in paper females. A normal
paphia female is dull orange in colour,
spotted with black, and has a gentle fluttering flight.
Magnus found however that the "ideal" female, i.e. the paper variant
most attractive to the male, was plain orange, up to 4 times the
size of the male, and had a very rapid wing flutter-frequency of
about 120 Hz. This poses the question - why didn't female
paphia evolve to have huge bright
orange wings ?
The answer is
probably that the normal spotted female has
orange content to attract the male, while a plain orange female
would be too conspicuous to predatory birds. A spotted pattern is an
effective camouflage, given that the female spends the most
important part of her life i.e. the oviposition stage, fluttering
around in the dappled sunlight of mature woodlands. A plain orange
female would attract males more easily, but would quickly be found
by birds, and would not live long enough to lay her eggs.
- a species
with an instantly recognisable pattern ©
While wing colour is
important in the initial stages of mate location, pattern
recognition is a different matter, and only comes into play when the
butterflies are in close proximity. Conspicuous patterns such as the
black and yellow pattern of
or the black, red and white of
may be recognised at close distances, but it is obvious that subtle
patterns cannot be.
To illustrate this
point, simply imagine an alpine meadow with a mixed population of
species. All are very drab brown insects of similar size and shape,
differing only in minute details that could not possible be seen
with the poor resolution of a butterfly's eyes.
The same argument
applies to the
Fritillaries and the numerous Polyommatine blues, where many very
similarly patterned and closely related species share the same
butterflies relied solely on visual stimuli for mate recognition
they would waste almost all of their short lives chasing after the
wrong species, and reproduction success would be very low indeed.
During the initial "approach" phase of mate location males will
chase after almost any small moving object including falling leaves,
bees, and butterflies of any species and either sex. After this
initial contact, follow up behaviour depends on the response of the
chased object. Birds are avoided but other butterflies are always
investigated, using a combination of visual and chemical cues.
Ultra-violet patterns on the wings often enable butterflies to
recognise their own species. When butterflies get close to each
other they use chemical messaging, in the form of pheromones, which
provides additional confirmation of species, and tells them whether
they are of the same or opposite sex.
If the pheromones indicate that the object being pursued is a
conspecific male, the butterflies are often stimulated into aerial
dogfights in which they battle for ownership of good vantage points
from which to intercept passing females. These territorial battles
can last for several minutes, after which one male is ousted from
Alternatively, if the pheromones indicate that the object being
pursued is a conspecific female, the male is stimulated into
initiating courtship. In many species exposing a female to male
pheromones is enough to initiate instant copulation, but in other
species a complex courtship ritual involving a protracted series of
visual, tactile or olfactory stimuli and responses is necessary
before copulation can take place.
Flowchart : behavioural cycle of a typical butterfly
In the genus Heliconius most species
rely entirely on airborne chemicals to locate mates. Males of
hecale, ismenius and
are attracted by pheromones to
the pupae of conspecific females. The day before emergence a female
pupa will usually have several males in close attendance. A frantic
battle takes place the instant she hatches, as the males all
struggle to copulate with her, not even allowing her time to expand
and dry her wings. In some other Heliconius
species such as
sara the males don't even wait until the female emerges.
Instead they physically break open her pupa and copulate as soon as
her genitalia are accessible.
Males of Satyrinae, Hesperiinae, Pyrginae and Theclinae have
specialised scales on their forewings called androconia. These have
sacs at their bases containing pheromones which they disseminate
into the atmosphere via tiny hairs or plumes on the edges of the
scales. The pheromones are used to attract females and entice them
In Danainae the androconia are on the hindwings. The males have
tufts of hair-pencils at the tips of their abdomens which they brush
against the androconial scales to collect pheromones. These are
later disseminated by expanding the tufts when in the presence of
Males of several Ithomiine species gather at "leks", where they
release pheromones from hair-like androconial scales on the upperside
hindwings. These attract more males, which release further pheromones.
After a few days a lek may include a dozen or more different Ithomiine
species. Passing females are attracted by the complex fragrances, and
their presence stimulates the males to open their wings and release
further pheromones that entice the females into copulation.
The courtship behaviour of
butterflies in general is inadequately studied, but it is clear that
in most species the female will not permit the male to copulate until
he has completed an often complex ritual. This typically begins with
the male releasing airborne pheromones, which leads to the female
settling on foliage. The male might then begin a "courtship dance"
around the female, whirring his wings to waft his pheromones across
If the female
accepts his advances ( she may instead give him a rejection signal ),
there is often a
confirmation ritual in which contact pheromones ( cuticular
hydrocarbons ) come into play.
A well known example is the Grayling Hipparchia
semele, in which the male clasps the females antennae between
his wings to bring them into direct contact with his androconial
scales. The Orange Sulfur Colias eurytheme
behaves in exactly the same way.
example is the Wood White
in which the male and female sit on a leaf, facing each other,
exchanging chemical messages with their antennae. The male repeatedly
flicks out his long proboscis, whipping the female alternately on the
underside of her left and right wings. Both sexes periodically flick
open their wings. The butterflies are clearly communicating something
but the ritual does not appear to instigate copulation, so the nature
of the "messages" is unclear.
engaged in courtship ritual ©
protracted courtship which can last for several hours. The male
follows the female as she flies from place to place. When she settles
and opens her wings, he walks onto her hindwings, tapping them with
his antennae. The process is repeated numerous times over several
hours, during which the male will drive off any other intruding males.
Eventually the female leads him to a sheltered spot, typically beneath
a small bush, where copulation takes place.
males are also commonly seen
"wing-walking" on females, but this is invariably followed by the
female inverting her wings and raising her abdomen - a signal to the
male that she is rejecting his advances, and a sign
that she has already mated ( females of most butterflies only mate
female raises abdomen to signal rejection to male ©
are receptive, copulation takes place almost instantly, without any
observable pre-nuptial ritual. Most butterflies remain copulated
only for an hour or so, but the Brimstone is quite remarkable in
this respect - I once found a pair of Brimstones which remained
copulated beneath a bramble leaf for an amazing 17 days before
finally parting company !
usually mate with several females in the course of their lives.
Females of certain long-lived species such as the Monarch
will mate with several males, but in the
majority of species females normally only mate once. After mating,
the genital opening on the females of
and some other species becomes sealed, physically preventing them
from mating with other males. Males of the Apollo butterfly
female genital opening with a structure called a sphragis to prevent
other males from copulating.
In the case of species
which hibernate as adults, copulation occurs in the spring.
Brimstones for example
emerge in July, feed for a few weeks, and then go into hibernation
for several months. After awakening the following April, they are
mated, and then the females fly many miles, often across
inhospitable terrain, stopping to lay their eggs on any buckthorn
plants that they encounter on their travels. The butterflies thus
spread throughout the countryside, interbreeding with other
Brimstones that may have originated a considerable distance away.
The resulting high genetic diversity is probably a major factor in
the remarkable success of the species, which is able to exploit an
enormous range of habitats and climatic extremes, being found at
altitudes from sea level to 2800m, and having a range that
encompasses north Africa, the whole of Europe, and extends across
temperate Asia to Siberia and Mongolia.
Perching, patrolling, and territories
have traditionally divided the pre-nuptial behaviour of butterflies
into two groups - those that "patrol" and those that "perch".
species are those where the male actively patrols a regular or random
route through it's habitat in order to locate a female. Perching
species are those where the male spends long periods sitting on a
prominent projecting leaf, or on a particular rock or patch of ground,
which it uses as a vantage point from which to intercept passing
females. These vantage points form the bases of territories, which the
males will vigorously defend against other intruding males.
If two males meet, they twist and turn around each other in the air,
and end up spiralling upwards to a great height until the "intruding"
male ( usually a newly emerged individual which has not yet found it's
own perch ) is ousted from the territory.
A perch is simply a vantage point from which
males can get a good view of all passing insects. Each species has
it's own preferred type of perch however -
Apatura iris will perch at the top of a
prominent tree, usually on a hilltop, while the Duke of Burgundy
Hamearis lucina will perch on the leaf of
a bush, typically in a small glade or at the sunny intersection of
In both cases the butterflies
have homed in on a spot where they have a good view in all directions,
and can survey and intercept passing females.
In practice, any male, of either a patrolling or
perching species, will intercept any other flying insect of similar
size and colour, to investigate it and determine whether it is a
female of it's own species. Most males will try to fly over or around
a female in a particular direction. A
Silver-washed Fritillary male
for example will loop over and under a female as
she flies along a track, showering her with pheromones. A
Silver-spotted Skipper male on the other hand will perform a figure of
eight dance around a settled female, whirring his wings to waft
pheromones over her antennae.
pair ( female on left ) ©
In South American rainforests and cloudforests male Glasswings and
Tigers ( Ithomiinae ) often gather at ephemeral "leks". It usually
takes about 3-7 days for a lek to form, and it may exist for up to 3
months, during which time numerous individual males will come and
At the leks males
release pheromones from hair-like androconial scales on the
uppersides of their hindwings. These pheromones attract more males,
which release further pheromones. After a few days the lek may
contain between a dozen and several hundred individuals, comprised
of up to 20 or 30 different Ithomiine species.
Passing females are attracted to the leks by the complex fragrances.
Their presence stimulates the males to open their wings and release
other pheromones that entice the females into copulation.