Life Process of a Butterfly (Citrous swallowtail butterfly).

Biological classification

Phylum Arthropoda.

Reasons:

• Undergo moulting or ecdysis.
• They are haemocilic (have open circulation).
• Bilaterally symmetrical.
• Possess metameric segmentation.
• Butterflies have a chitinous exoskeleton.
• Presence of jointed appendages attached to each segment.
• They are also triploblastic coelomates.

Class Insecta:

Reason:

• Possess a pair of compound eyes.
• The body is divided into three (head, thorax, and abdomen).
• They also possess a pair of antennae (feelers).
• Presence of three pairs of thoracic legs.
• Also possesses two pairs of wings.

Order Lepidoptera:

Reason;

• Mouthparts are modified as a coiled proboscis for sucking.
• Wings and body are covered with scales.
• They also exhibit complete metamorphosis.

The Structure of a Butterfly.

The body structure of a butterfly is divided into three.

• the head,
• the thorax,
• and the abdomen.

The Head:

• The head bears a pair of compound eyes.
• A pair of club-shaped antennae is found on the head.
• The head also has a mandible, labium, and labrum (mouthparts).
• A pair of maxillae is modified into a long, hollow, flexible, coiled tube called a proboscis.

The Thorax:

• The thorax is divided into three segments. (Prothorax, Mesothorax, and Metathorax).
• Each segment bears a pair of jointed legs.
• The mesothorax and mesothorax bear a large membranous wing, which is covered with scales.
• Each hind wing has two eye spots for protection against predation.

The abdomen:

• The abdomen is made up of segments.
• The segments are covered with hair.

Life cycle.

• A butterfly undergoes a complete metamorphosis during its life cycle. (Eggs, larva (caterpillar), pupa, and imago)
• The male and female butterflies are attracted to each other by the colour patterns and chemicals.
• The male then deposits sperm into the genitalia of the female.
• The eggs are fertilized internally.
• The eggs are laid on the undersurface of leaves after which each egg hatches into a larva called a caterpillar.

The Larva Stage of The Life Cycle of the Butterfly (The Caterpillar)

• It has a head, thorax, and abdomen
• It has a small head that bears the mouthparts for chewing.
• Has no compound eyes but six ocelli
• A pair of short antennae
• It also has nine pairs of spiracles, one pair on the prothorax, and eight pairs on the first eight abdominal segments.
• The thorax bears three pairs of walking legs
• The 3d, 4h, 5h, and 6″ abdominal segments bear cushion feet called prolegs
• The tenth abdominal segment is modified into a pair of claspers
• The functions of the legs, prolegs, and claspers are for walking and holding firmly to the plant.
• Has a structure called the osmeterium.
• Osmeterium has a foul smell, which provides defense.
• Pairs of spiracles on the thorax and abdomen for gaseous exchange.
• It feeds actively and grows actively, and also moults several times.
• The caterpillar stops feeding and produces a silk pad called the cremaster on the plant
• Silk girdle (cocoon) around its thorax.
• After this, the caterpillar larva moults the last time and changes to a pupa called a chrysalis
• The silk girdle (cocoon) protects the larva against drying up and predators

The Pupa (Chrysalis)

• It possesses brown and green colours, making it camouflaged, thereby protecting itself from enemies.
• At the pupal stage, the body parts such as compound eyes, antennae, wings, proboscis, and reproductive organs are formed.
• At the end of the pupal stage, the pupa case splits open and the young adult climbs out and rests for 2 hours for its wings to expand and harden before flying away.

Economic importance of the butterfly

(The larva and adult are both pests of citrus)

• The larva destroys citrus leaves
• The adult destroys citrus fruits
• The adult also pollinates flowers
• Some caterpillars produce silk
• Used as ornaments

Explain how butterfly affects crop production.

Butterflies affect crops as pollinators and pests.

As pollinators,

• when they visit a flower to suck nectar with their proboscis
• Pollen grains adhere to the underside of the insect.
• As it visits another flower to obtain more nectar,
• Pollen from its body gets dusted on the stigma of the flower, thereby bringing about pollination.
• And increasing crop yield and fruit production

As a pest,

• They feed on fruits using their proboscis to pierce the fruit to suck the juice.
• This leads to the destruction of the fruit and brings loss to the farmer.

State similarities between the imago and caterpillar.

• Presence eyes
• Both possess eyespots.
• Three pairs of thoracic legs.
• Three body divisions.
• Spiracles
• Possession of a segmented body.

Differences between the imago and the caterpillar

State the adaptive features of a caterpillar to escape danger.

• Possess colour which provides camouflage and blends with the leaves.
• Osmeterium produces a foul smell temporarily to scare predators.
• Presence of eyespot frightens predators.

Importance of the caterpillar in agriculture.

• They feed on the leaves of plants (crops).
• Caterpillar pierces and sucks citrus fruits, causing premature fruit fall and reducing yield.
• They also pollinate the flowers of crops, leading to fertilization and fruit formation.

Revision Questions.

• State five observable features of the butterfly.
• List five observable features of the caterpillar.
• Give five economic importance of the butterfly.
• State four differences between a caterpillar and a butterfly.
• State three differences and similarities between moth and butterfly.

References:

• Adams, B. J., & Crawley, J. L. (2013). Van De Graaff’s photographic atlas for the biology laboratory (7th ed.). Morton Publishing Company.
• Freeman, S., Quillin, K., Allison, L., Black, M., Taylor, E., Podgorski, G., & Carmichael, J. (2017). Biological Science (6th ed.). Pearson; A student centered approach to the study of biology.

Source: Galmeek.com

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