• Butterfly Basics


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    • Abstract: Butterfly BasicsClassificationScientists classify all organisms using a system that divides largegroups of organisms into smaller groups of organisms based on physical andfunctional characteristics. The following illustrates the scientific naming of

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Butterfly Basics
Classification
Scientists classify all organisms using a system that divides large
groups of organisms into smaller groups of organisms based on physical and
functional characteristics. The following illustrates the scientific naming of
a Spicebush Swallowtail going from the largest grouping to the smallest
grouping:
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Papilionidae
Genus: Papilio
Species: Papilio troilis
All animals are placed in the kingdom Animalia. The Kingdom Animalia
is subdivided into Phylums. Butterflies are in the phylum Arthropoda. All
Arthropoda have the following characteristics:
• They are invertebrates (no backbone)
• They have an exoskeleton
• They have bodies that are divided into segments
• They have jointed legs
The phylum Arthropoda includes: crustaceans, spiders, centipedes,
millipedes and insects. The phylum Arthropoda is subdivided further into
classes. Included is the class Insecta. The common characteristics of the
class Insecta are:
• They have an exoskeleton
• They have six legs
• They have three main body parts: head, thorax and
• abdomen
• They have one pair of antennae
• They have compound eyes as adults
• They develop through a process called
metamorphosis
The next subdivision is Order. Butterflies are in the Order
Lepidoptera. The word Lepidoptera is derived from two Greek words.
“Lepidos” meaning scales and “Pteron” meaning wing.
The Order Lepidoptera is subdivided into families. Some of the most
common families are papilionidae (Swallowtails), Nymphalidae (Brush-footed
Butterflies), Lycaenidae (Gossamer Wings), Libytheidae (Snout Butterflies),
Pieridae (Sulphers and Whites).
Every organism has a species name that is created from the genus and
a specific epithet or descriptive word. For example: Papilio troilis is the
scientific name (species name) of the Spicebush Swallowtail. Scientific
names are italicized or underlined. The genus is capitalized and the specific
epithet is written in lowercase.
Most organisms also have a common name. The common name of
Papilio troilis is the Spicebush Swallowtail. The problem with common names
is that a single organism can have several different common names depending
on where it is found.
Butterfly Anatomy
Butterfly bodies are divided into three regions: the head, thorax and
abdomen. The important features on the head are the eyes, antennae and
the proboscis. As an adult, butterflies have two large compound eyes. Each
eye is made up of facets. Butterflies can see into the ultraviolet range of
the light spectrum. Antennae are sensory organs that can be used for taste,
smell, feel and navigation. The proboscis is a long slender tube. The
butterfly uses its proboscis to sip nectar from plants. When not in use the
proboscis is kept tightly coiled underneath the head.
The thorax contains the wings and legs. The wings are located on the
thorax and are covered with millions of scales. The front pair of wings are
called the forewings and the rear wings are called the hindwings. The scales
create the colors on the wings. There are two types of coloration: pigment
and structural. Scales that have pigments appear red, orange, black, yellow
and earth tone colors. Structural coloration produces iridescent blues,
greens, purples and silvers. Wing coloration has many different functions.
Temperature regulation is an important function. A butterfly’s metabolism
is dependent upon environmental conditions. If it is warm outside a
butterfly will be more active, if it is cold it will be less active. Darkly
colored wings help absorb heat and warn up the butterfly faster. Warning
colors can provide protection against predators. This lets predators know
that the butterfly is toxic. Butterfly wing coloration is also important in
mate selection. Patterns are created that are recognizable to the opposite
sex. Finally, butterflies that have full, mottled patterns use these colors to
blend in with their surroundings.
Butterflies have 3 pairs of jointed legs that are attached to the
thorax. At the end of the legs are tarsi (feet). Butterflies have sensory
organs on their tarsi that are sued to taste. This helps them select the
right plant to lay their eggs on. Also the tarsi have tiny claws that help
them cling to substrates.
Located on the sides of the thorax and abdomen are breathing holes
called spiracles. Air enters through the spiracles and flows directly to the
cells through an internal tube system called tracheoles. Butterflies do not
have lungs.
Butterfly, Moth or Skipper?
Butterflies, moths and skippers all belong to the same Order
Lepidoptera. There are several differences but the key-defining
characteristic is the antennae. Some Lepidopterists consider skippers to be
their own grouping, some lump them in with butterflies.
Butterflies Moths Skippers
Antennae clubbed Antennae not clubbed Antennae clubbed with
hooked ends
Typically wings held Typically wings held Typically wings held
closed when at rest closed when at rest open when at rest
Most are diurnal Most are nocturnal Most are diurnal
Most are brightly Most are dull colored Most are dull colored
colored
Body slender and Body thick Body thick and hairy
smooth
Key Ideas
• Butterflies are scientifically classifies.
• Butterflies, moths and skippers form the Order Lepidoptera.
• Butterfly wings are covered with scales.
• Butterfly wings serve several purposes: Camouflage, warning to
predators, temperature regulation and mate selection.
• The most important distinguishing characteristic between butterflies,
moths and skippers are their antennae.
LIFE CYCLE BASICS
The Life Cycle of Butterflies
The word metamorphosis means, “ to change form”. Butterflies go
through complete metamorphosis. This means that there are 4 distinct
stages: egg, larva, pupa and adult. The duration of each one of these stages
is dependent on the species of butterfly, the geographic location of the
butterfly and time of the year. It can take a butterfly a couple of weeks or
over a year to comp lete its life cycle. Generally, under ideal conditions the
egg stage lasts from 3-6 days, the larval stage 2-4 weeks, the pupae 2 to 4
weeks and the adult 1- 4 weeks.
Egg Stage
The life cycle begins when the female lays an egg. Females seek out
specific kinds of plants (host plants) that their larvae can feed on. They
locate the correct plant by sight and smell. A female butterfly will often
scratch the leaves of a plant that she has located by sight. Then by smelling
the plant with sensory organs on her tarsi she can determine whether or not
she has located the right hostplant for her young. If she detects the
correct smell she will then lay an egg and attach it to the plant with a fast-
drying glue-like chemical that she secretes. Some examples of butterflies
and their host plants are: Monarchs lay their eggs on milkweeds; Spicebush
Swallowtails lay on stinging nettle.
Butterfly eggs are about the size of a pinhead and vary in color and
shape. Many butterflies will lay their eggs single but others will deposit
them in clusters. For example the Monarch butterfly lays her eggs single
but the Morning Cloak will lay her eggs in clusters. Most species of
butterflies will lay hundreds of eggs, but there are a few exceptions that lay
over a thousand in a lifetime.
Larval or Caterpillar Stage
The second stage of a butterfly’s life is the larval or caterpillar stage.
Once a caterpillar has hatched from its egg, it eats the eggshell and then
begins eating the leaf it was laid on. Caterpillars are very picky about what
they eat and will only feed on the correct host plant. If you are rearing
caterpillars at home or in the classroom it is very important to know what
kind of plant they eat. If a caterpillar is given the wrong kind food it will
stop eating and starve to death.
As the caterpillar feeds it grows. This presents a problem to
organisms that have an exoskeleton. So, in order for the caterpillar to get
bigger it has to shed its exoskeleton. The shedding of the exoskeleton is
called molting. As the caterpillar matures it molts or sheds its old, small
skin. Each molt reveals a new, larger skin, which accommodates the growing
caterpillar.
Anatomically speaking all caterpillars are similar. A caterpillar’s head
capsule is armed with chewing mouthparts, simple eyes and spinnerets, which
produce silk. Most caterpillars have 13 body segments. From head to tail
they bear three pairs of jointed walking legs, 4 pairs of prolegs and a pair of
claspers. Spiracles on several body segments allow caterpillars to breath.
Pupa or Chrysalis Stage
The word chrysalis comes from the Greek word “cyrsos” meaning
golden. Chrysalis can take on many forms. Some are leaf mimics, while
others are covered with gold flecks.
This is where the transformation from a caterpillar to a butterfly
takes place. Inside the chrysalis the caterpillar’s tissues are broken down
into a “cellular soup”, reorganized and gradually rebuilt into the adult
butterfly. Some butterflies pass the winter as a chrysalis while others are
in this stage for only a few weeks.
Adult Stage
When the butterfly emerges from the chrysalis, it is unable to fly. It
hangs upside down from the empty chrysalis shell or from a nearby branch
or leaf. When it emerges its wings are wrinkled and damp. The butterfly
has to pump blood from its swollen abdomen into its wings to inflate them.
This can take up to an hour.
The butterfly also has to fuse its proboscis together. The proboscis
of a newly emerged butterfly is separated into two halves. As the butterfly
coils and uncoils the proboscis it zips them together forming the straw like
feeding tube. Once the wings are inflated and hardened and the proboscis is
zipped the butterfly will fly away in search of food and a mate.
Key Ideas
Butterflies have 4 life stages: egg, larva, pupa and adult. Butterflies
require specific host plants on which to lay their eggs for their caterpillars
to eat.
BUTTERFLY BEHAVIOR
Basking
The temperature of its environment dictates a butterfly’s body
temperature. When the environment is cool a butterfly is cool and its
metabolism works at a slower rate. When it is warm the butterfly’s
metabolic rate is higher, creating sufficient energy for flight and other
activities. One way to raise its body temperature is to bask. A butterfly
that wants to bask will find a sunny and safe place to sit where it can spread
open it’s wings and catch the sun’s warming rays. In order to fly, a
butterfly’s body temperature must be between 82 and 100 degrees
fahrenheit.
Flight
Flying allows a butterfly to locate food and mates, escape predators,
and in some cases migrate. Muscles in the thorax control the wings. These
muscles contract and relax to produce the wing-flapping movement. This in
turn creates lift.
There are several different kinds of flight: darting, gliding,
zigzagging, fluttering, etc. Different butterflies display different types of
flight. A lepidopterist can use patterns of fight to help in the identification
of a butterfly.
Roosting
Most butterflies are diurnal. So where do they go at night? At night
they roost underneath the foliage of trees, plants, shrubs or grasses.
Butterflies will even roost on overcast days, because they can’t raise their
body temperature high enough, without the help of the sun, to fly. Some
butterflies, like the Zebra Longwing, roost in-group, while other roost singly.
A butterfly that is roosting will hang upside down with its wings
closed. This position allows it to display the usually full colored underside of
its wings. Displaying the full colored underside of wings helps camouflage it
from predators.
Feeding
A butterfly spends most of its time searching for food. Once it
locates a food source it extends its proboscis and probes for nectar.
Nectar is the most common food source for butterflies but some also feed
from the juices of overripe fruit, carrion, manure and tree sap in addition to
nectar.
Puddling
You will frequently observe butterflies clustered around a puddle, a
muddy spot or near a stream. This is referred to as puddling. Males most
commonly display puddling behavior. Scientist believes that puddling
provides important nutrients like salts and minerals that the butterflies
can’t get from nectar alone. Swallowtails, blues and sulphers commonly
puddle.
Courtship and Mating
Typically the male will seek out the female. To find females the males
will engage in two basic types of mate-seeking behavior: perching and
searching. Some males will pick a high spot in their environment and watch
for passing females. If an object of the correct size, shape and coloration
of a female passes by the male will leave his perch and investigate. If it is a
female and she is receptive courtship will begin. If the male finds an
unreceptive female, male, or a butterfly of another species, he will return to
his perch.
Other males will display searching or patrolling behavior. Males will
fly a route and possibly release pheromones that attract females. If the
male encounters a receptive female along his patrol (route) courtship will
begin.
Every species of butterfly has a unique courtship ritual. Butterflies
mate on the ground or in the air. The actual mating act can last from 20
minutes to several hours. Some butterflies mate only once, some will mate
several times. During mating the male passes a spermatophore, a “package”
of sperm and protein, to the female.
Key Ideas
• A butterfly’s metabolism is dependent upon the environmental
temperature. They are “cold blooded”.
• Butterflies bask in the sun to raise their body temperatures.
• Flight allows butterflies to locate food, mates and host plants.
• Flight allows butterflies to escape predators.
• Butterflies roost at night.
• Butterflies display puddling behavior to obtain salts and minerals.
• Butterflies feed on a variety of liquids, including nectar and the juices
from overripe fruit, carrion and manure.
• The courtship behavior of butterflies is unique to each species.
Special thanks to John Mugg of Michigan State University for the use of his butterfly
information.


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