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The butterfly
lifecycle
1 - Egg
- anatomy, oviposition
2 - Caterpillar
- anatomy
3 - Caterpillar
- hatching, feeding and development
4 - Caterpillar
- cannibals, carnivores and myrmecophiles
5
- Caterpillar
- survival mechanisms,
armature, camouflage / disguise
6
- Caterpillar
-
co-evolution with plants
7
- Chrysalis
- pupation, metamorphosis
8 - Adult
- emergence, feeding
9 - Adult
- mate location and courtship
10 - Adult
- daily routine, roosting, hibernation, lifespan
Adult
: daily routine, roosting, hibernation, lifespan
The
daily routine
Male and female butterflies of any given species usually behave very
differently. In most species the males are highly active, and their
behaviour follows a predictable cycle of feeding, basking, and
patrolling in search of females. Males of other species are often
highly territorial, and will defend their territories against other
insects including wasps, flies, and flying beetles. If another male
of the same species enters their territory, they engage in an aerial
sortie, spiralling high above the trees until the intruding
butterfly is ousted.
Female
butterflies live entirely different lives. Prior to mating they are
often sedentary, remaining very close to the spot where they emerged
from the pupa. After mating they seek places to lay their eggs, but
usually fly only short distances between bouts of egg laying.
These
differences in behaviour are reflected in their appearance - males
need to be noticed, so are generally more colourful than females.
The Adonis Blue
Lysandra bellargus is a good
example : the males are a brilliant iridescent blue colour, but the
females are drab dark brown creatures - they spend most of their
time crawling about on the ground amongst short grasses, looking for
places to lay their eggs, but need to bask periodically so they can
maintain their body temperatures. When basking on the ground, their
drab colouration helps to camouflage them so they escape predation.
Adonis
Blue
Lysandra bellargus, male, Ballard
Down, Dorset ©
Adrian Hoskins
Adonis Blue
Lysandra bellargus, female, Ballard Down, Dorset ©
Adrian Hoskins
Roosting behaviour
In cool or rainy weather butterflies are
inactive, and thus particularly vulnerable to attack by birds and
small mammals.
In tropical areas many species hide away
beneath leaves, even when sunny, and only come into the open to
undertake specific tasks such as feeding or reproducing. This
behaviour is very widespread amongst the metalmarks ( Riodinidae )
and Spreadwing skippers ( Pyrginae ).
Eurybia
molochina, ( Riodinidae ) hiding
beneath a leaf in the Peruvian rainforest ©
Adrian Hoskins
In temperate zones, during periods of inclement
weather, members of the Papilionidae
and Pieridae normally roost beneath the leaves of herbaceous
plants.
Pyrgines such as
the Grizzled Skipper
Pyrgus
malvae usually roost at the top of dead flower-heads. The Dingy
Skipper Erynnis tages behaves similarly, but takes things a stage
further by wrapping it's wings tightly around dead knapweed
flowers, where it is almost impossible to see
( unless you are a
very determined entomologist ! ).
Erynnis tages,
( Pyrginae ) roosting on a dead knapweed flower, Hampshire ©
Adrian Hoskins
Polyommatine Blues and Satyrines such as Small
Heath, Marbled White and Meadow Brown tend to roost in a head-downwards posture at the
top of grass heads. Pearl-bordered Fritillaries
Clossiana euphrosyne and other
Melitaeines adopt a similar tactic, often
roosting on bracken fronds or on the flowers of rushes. Such strategies may at first seem a little
difficult to understand, as the butterflies are easily spotted. The probable
explanation is that they are selecting sites where they are out of reach of
nocturnal predators such as voles or shrews.
Clossiana selene,
( Nymphalinae : Melitaeini ) seed-head, Wiltshire, Kent ©
Adrian Hoskins
Hibernation
Hibernation is a process that depresses
metabolism and energy consumption during the cold winter months. It
ensures that energy is not wasted on fruitless searches for nectar
and foliage in winter, and synchronises the spring reawakening with
the time when flowers and fresh foliage reappear.
In temperate
regions of the world most
butterfly species overwinter as larvae. Others hibernate as
eggs or pupae. A small number, including
Inachis io,
Polygonia c-album and Gonepteryx rhamni
overwinter instead as adult butterflies.
To successfully overwinter they need to find
a place to hide where they are protected from the worst of the
wind, rain and snow. They may be in diapause for several months,
and throughout this period they must remain undetected by birds.
Accordingly they have evolved cryptic colours, patterns and
unusual wing shapes that combine to provide them with effective
camouflage. The Brimstone
Gonepteryx rhamni for example
hibernates under bramble or ivy leaves and has wings coloured to match winter foliage. Its wings are also leaf-like
in shape
and have raised venation to simulate the veins of real leaves.
Gonepteryx rhamni,
( Pieridae ) hibernating beneath a bramble leaf, West Sussex ©
Adrian Hoskins
Many overwintering species such as the Peacock
Inachis io,
Camberwell Beauty
Nymphalis antiopa and Large Tortoiseshell
Nymphalis polychloros hibernate
beneath logs or in hollow tree trunks; or in other dark places
such as caves or animal burrows. These species have evolved very
dark ventral wing patterns which make it difficult for foraging
birds to locate them in their gloomy surroundings.
A few species such as the Comma
Polygonia c-album hibernate openly,
hanging from tree branches or amongst piles of leaf litter on the
forest floor. Their dark marbled patterns and strange angular wing
shape provides them with an extremely effective dead-leaf
disguise.
Polygonia c-album,
( Nymphalidae ) hibernating beneath a branch, West Sussex ©
Adrian Hoskins
Lifespan
The whole
lifecycle from egg to adult can take just 3 weeks to complete in
many tropical species. In temperate regions the lifecycle
of the summer generation may be complete within 6 weeks, but
many species only produce a single generation in a year. In
sub-arctic zones some species such as
Parnassius eversmanni,
Boloria natazhati
and
Oeneis alpina
take 2 years to complete the lifecycle.
The lifespan of butterflies varies
considerably from one species to another. Captive butterflies, if fed regularly can live for
several weeks.
Wild butterflies are subject to predation and the extremes of
climate, so while some may have the potential to live longer, in practice the average lifespan is just 7 or 8 days.
There
are however several notable exceptions to this general rule. Some
butterflies, e.g. Monarchs, Commas and Tortoiseshells, hibernate as
adults, and these species often live for several months. The longest
lived European species are the Brimstone and
Peacock - both emerge
in early July, and often survive until the following June.
Certain tropical species are also capable of surviving for equally
long periods.
In Central & South America female
Heliconius butterflies sequester pollen from
Psiguria,
Anguria and Gurania flowers in the
rainforest.
The pollen collected
from the flowers is processed by the females to extract amino
acids which increase longevity and enable them to produce eggs
for up to 9 months. Other tropical species e.g. the Satyrine
Taygetis mermeria and certain Ithomiines, Heliconiines
and Danaines
are able to extend their lives by
aestivating during the dry season, and can
live for up to 11 months.
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